JPH07256149A - Centrifuge motor controller - Google Patents

Abstract

(57) [Summary] [PROBLEMS] The present invention relates to a motor control device that rotationally drives a centrifuge rotor. An object of the present invention is to exchange electric power with an AC power supply during power running / regenerative operation of the motor, A bidirectional power converter for a power supply which operates so as to reduce the wave current content, in which the characteristics of a low speed rotation region of power running start and regenerative deceleration of a motor are improved. [Configuration] A bidirectional power converter 22 for a power supply, which operates so as to reduce a harmonic current content with respect to an AC power supply 21, and a P
A DC power converter 159 is provided between the inverter converters 26 for the WM control motor, and the DC power converter 159 is used by the controller 100.
Controls the operation of two transducers.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device for driving a centrifuge rotor, and in particular, suppresses harmonic components of a current passing through an AC power supply in all operating states of the motor, The present invention relates to a control device with improved waveform distortion and power factor.

[0002]

2. Description of the Related Art A conventional motor control device for a centrifuge in which harmonic components of a current passing through an AC power supply is suppressed is such that conversion of electric power between an AC source and a DC source is not converted from an AC source to a DC source. A bidirectional power converter for power supply that acts as a step-up converter and acts as a step-down converter for conversion from a DC source to an AC source, and an inverter for a motor that uses a DC source as a power source to power and regenerate a motor that rotationally drives a rotor. When the motor is equipped with a converter to increase the rotation speed of the rotor, the motor is controlled by PWM control and positive slip control via the inverter converter for the motor by the DC power source boosted by the bidirectional power converter for the power source. When the motor is driven and the motor is regeneratively braked to lower the rotation speed of the rotor, the motor is controlled by PWM and minus slip control via the motor inverter converter. The electric energy regenerated to drive and DC power boosted by the bidirectional power converter power supply was then returned to the AC power source.

[0003]

In such a conventional motor control device for a centrifuge, when the motor is powered, the bidirectional power converter for the power supply functions as a boost converter, so that the motor is stopped. When the motor is started from, the voltage applied to the motor is insufficiently suppressed by PWM control by the motor inverter converter, and it is difficult to smoothly start up the rotation speed. The operation of the power converter as the boost converter is stopped, and the PAM control for adjusting the DC voltage output by the phase control by the AC phase control element is activated in combination. Therefore, when the harmonic current component cannot be reduced during phase control, and the power supply voltage waveform is significantly distorted, an appropriate firing signal cannot be temporarily obtained and phase control becomes impossible and an excessive current flows to the switching element to start. It had the drawback of leading to failure. On the other hand, when the motor is regeneratively braked, the power supply bidirectional power converter acts as a step-down converter, so when the motor is decelerated to a low speed range, the regenerative voltage from the motor inverter converter exceeds the power supply voltage. There was a problem that power did not occur and power was not converted to the power supply.

The present invention has been made in order to eliminate the above-mentioned drawbacks of the prior art, and its purpose is to perform phase control while the bidirectional power converter for power supply is operating in the power running of the motor. Therefore, it is an object of the present invention to provide a centrifuge motor control device capable of smoothly starting a motor from a stopped state and regenerating electric power to a power source in a low speed rotation region in regenerative braking of the motor.

[0005]

SUMMARY OF THE INVENTION The above-mentioned object is to systematically link an AC power supply, operate so as to reduce the content of harmonic components of the current passing through the power supply, and perform a forward conversion from an AC source to a DC source. It becomes a step-up converter, and on the other hand, it operates as a step-down converter when converting from a DC source back to an AC source, and a bidirectional power converter for the power supply and a motor inverter that inputs and outputs electric power to and from the DC source, and runs the motor in a regenerative operation. When a converter is provided, the output of the bidirectional power converter for the power supply is stepped down between the bidirectional power converter for the power supply and the inverter converter for the motor when it is supplied to the inverter converter for the motor. It functions as a converter, and conversely, when supplying the output of the motor inverter converter to the bidirectional power converter for power supply, it controls the DC power converter that operates as a boost converter and these three converters. It is achieved by providing a control device.

[0006]

In the centrifuge motor controller configured as described above, the DC power converter converts the DC output of the bidirectional power converter for power supply into a step-down converter when the motor is started from a stopped state during power running. It is reduced by the action, and the voltage applied to the motor is adjusted in cooperation with the PWM control of the inverter converter for the motor to smoothly accelerate. During the acceleration, the DC power converter outputs the DC output of the bidirectional power converter for the power supply. Is gradually increased, and at the time of settling, the control device operates so that the DC output of the bidirectional power converter for power supply is directly output to the inverter converter for motor.

Further, when the motor during high speed rotation is decelerated and stopped by regenerative braking, the DC converter boosts the DC power output from the motor inverter converter slightly when the motor is in the high speed rotation range. And outputs it to the bidirectional power converter for the power supply, and when the motor reaches the low speed rotation range as the motor decelerates, the AC converter acts as a boost converter on the low voltage regenerative DC power output from the inverter converter for the motor. Thus, the voltage is greatly boosted and output to the bidirectional power converter for power supply.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described in detail below with reference to the drawings. In the block diagram shown in FIG. 1, which is a specific embodiment of the present invention, 21 is an AC power source, 22 is an AC side connected to an AC power source 21 via a reactor 23, and a DC side is connected to a smoothing capacitor 24. A bidirectional power converter for a power supply in which a switching element such as a transistor, iGBT, FET, or GTO is connected in reverse parallel to each of the rectifying elements constituting the reflux rectifying circuit.
Reference numeral 6 denotes a return rectifier circuit connected to a motor 28 for driving a centrifugal rotor 27 such as an induction motor on the AC side and connected to a smoothing capacitor 151 on the DC side, and to respective rectifying elements constituting the return rectifier circuit. Bidirectional power converter for power supply 22
159 is a motor inverter converter to which switching elements of the same type as those of FIG.
And 151 is a DC power converter for performing bidirectional voltage conversion of DC power, and is a bidirectional power supply that is connected in series to the positive line 24a and the negative line 24b of the smoothing capacitor 24 and has a reflux rectifier. A switching element composed of switching elements of the same type as the power converter 22 is connected in parallel, and a choke coil 150 is provided between the connection point of the series connection and the positive line 151a of the smoothing capacitor 151.

Six switching elements of the motor inverter converter 26, 26u, 26v, 26w, 26x, 2
In 6y, 26z PWM inverter control,
Reference numeral 29 is a ROM that stores the ON / OFF pulse pattern of the switching element, and the logical values of “1” and “0” of the output data of the data output line of the ROM 29 are the pulse patterns. The data is sequentially read by the output of the counter 30 connected to the address line, and the clock of the counter 30 is applied by the clock output of the PLL pulse generator 31, and the timer LSI 32 causes the PLL pulse generator 31 to output data. The clock output frequency is controlled. Three
Reference numeral 3 is a latch for preventing time irregularity of data read from the ROM 29 and synchronizing it. Reference numeral 34 is a gate driver for driving the photocoupler 35 in accordance with the output logic of the latch 33. ON / OFF of the six switching elements of the bidirectional power converter 26 is controlled.

In controlling the four switching elements 22U, 22V, 22X, 22Y of the bidirectional power converter 22 for power supply, 36 is an iC for power factor correction control, and the pulse width control output of this iC is It is amplified by the gate driver 38 via the pattern switch 37 and drives the photocoupler 39. The signal output of the photocoupler 39 controls ON / OFF of the four switching elements of the bidirectional power converter 22 for power supply. IC36 for power factor correction control is
The bidirectional power converter for power supply 22 cooperates with the reactor 23 to smooth the smoothing capacitor 24 while the motor 28 is in the power running mode with a current having a low harmonic current content similar to the voltage waveform of the AC power supply 21.
Is operated as a step-up converter for charging the constant voltage to a constant voltage, and reverse operation is performed as a step-down converter for discharging the charge stored in the smoothing capacitor 24 to keep the voltage at a constant voltage during regeneration of the motor. Therefore, V due to insulation transformer
Charging the smoothing capacitor 24 by the CV1 sensor 42 by the combination of the VF and FV converters in which the power supply voltage waveform is obtained by the sensor 40, the power supply current waveform is obtained by the i sensor 41 such as a hall count sensor, and the VF and FV converters are insulated by a photocoupler. A voltage signal is provided as the sensor input signal. Reference numeral 43 is an analog switch, and the signal output of the i sensor 41 is an attenuator so that the above-described forward operation and reverse operation of the bidirectional power converter 22 for power supply can be performed by the same control action of the iC for power factor correction control. The signal output of the CV1 sensor 42 is provided so as to be switched and selected by the switch 44 and the subtraction signal based on the reference voltage source 46 can be switched and selected by the differential amplifier 45. I /
Switching is performed in cooperation with the pattern switch 37 by the signal output of the OLSI 47.

Reference numeral 48 is a positive / negative cycle detector of the power source which detects the positive / negative cycle state of the AC power source 21 and outputs a logic signal to the pattern switch 37, and 51 outputs the signal output to the timer LSI 32. It is an oscillator that serves as a reference clock source for the PLL pulse generator 31 and the like.

In controlling the two switching elements 159A and 159B of the DC power converter 159, 15
7 is a step-up converter iC for controlling on / off of the switching element 159B, and 156 is a switching element 159.
A step-down converter iC that controls ON / OFF of A,
Reference numeral 152 denotes a CV2 sensor that measures the charging voltage of the smoothing capacitor 151 by the same means as the CV1 sensor 42. The signal outputs of the CV1 sensor 42 and the CV2 sensor 152 are the boost converter iC157 and the step-down converter i, respectively.
A D having a D-A conversion function and an A-D conversion function as well as being input as a DC voltage control feedback signal to the C156.
-A / A-D is input to the AD conversion terminal of the LSI 158, while the boost converter iC157 and the step-down converter iC15 are input from the DA conversion terminal of the LSI 158, respectively.
6 is output as a DC voltage control reference signal, and the centrifuge control CPU 55 can perform step-up control of the smoothing capacitor 24 and step-down control of the smoothing capacitor 151 via the step-up converter iC157 and step-down converter iC156. . The pulse width control outputs of the step-up converter iC157 and the step-down converter iC156 are output to the step-up / down switch 155, which selects the step-up / step-down operation, is sent to the gate driver 154, and is output to the gate driver 154 to output two signals. Switching elements 159A, 15
When 9B is selected and ON / OFF is controlled and the DC voltage of the smoothing capacitor 24 is reduced to charge the smoothing capacitor 151, the switching element 159A operates to boost the DC voltage of the smoothing capacitor 151 to smooth the smoothing capacitor. When charging to 24, the switching element 159B operates.

The power supply control circuit 52 is a circuit for supplying drive power to the gate drivers 34, 38, 154, and constitutes the motor inverter converter 26, the DC power converter 159, and the power supply bidirectional power converter 22. When abnormalities such as switching element overcurrent or arm short circuit occur,
Alternatively, it is provided in order to prevent an ON signal from being applied to the switching element constituting the converter after the AC power supply 21 is turned on until the preparation for the operation of the entire control device is completed, and at the time of switching the control state during other operation. There is.
53 is a rotation sensor for detecting the rotation of the rotor 27, 54 is a counter circuit for measuring the number of rotations of the rotor 27, 55 is a timer LSI 32, I / O LSI 47, D-.
This is a centrifuge control CPU that controls the A / A-D LSI 158 and the counter circuit 54. Reference numeral 100 denotes a control device that performs on / off control of the switching elements of the motor inverter converter 26, the DC power converter 159, and the power supply bidirectional power converter 22.

As described above, the V-sensor 40, i-sensor 41, CV1 sensor 42, CV2 sensor 152, and the photo-couplers 35, 39, and 153, which are signal isolation means, serve as an electric power circuit for the motor inverter converter 2.
6, DC power converter 159, bidirectional power converter for power supply 2
The reference potential is insulated between the control unit 100 and the control unit 100, which is a signal circuit, and the control device 100 may be affected by malfunctions or the like due to noise generated by the high-speed switching operation of the switching element in the converter. It prevents you from receiving it. Further, in order to prevent the other devices connected to the AC power source 21 from being adversely affected, in FIG. 2 showing a part of another embodiment of the present invention, parts having the same functions as those in FIG. In order to prevent these noises from being transmitted to the AC power supply 21, the reactors 23 are provided on both lines of the AC power supply 21, and the low-frequency filter 56 of the common mode choke coil is also provided. Common-mode noise bypass capacitors 58a and 58b whose common connection ends are connected to the ground 60 and normal-mode bypass capacitors 59a and 59b are used.

Next, the operation of the present invention will be further described with reference to FIG.
~ It demonstrates with reference to FIG. 3 to 15, parts having the same functions as those in FIG. 1 are designated by the same reference numerals.

FIG. 5 shows the number of revolutions of the rotor 27, that is, the motor 28, which is suitable for the control device for the centrifuge motor according to the present invention.
Is a graph showing the elapsed time of the rotation speed of the
Is a process of gradually accelerating the rotor 27 from a stationary state by a slow accelerator. To cope with this slow accelerator, the bidirectional power converter 22 for power source is operated in the forward direction to charge the AC power source 21 with a boosted voltage. Even if the charging voltage of the smoothing capacitor 24 is input to the motor inverter converter 26 as it is and the voltage applied to the motor 28 is adjusted by the PWM control of the converter 26, the voltage is not squeezed and a smooth start is performed. DC power converter 1
By the step-down converter action of 59, the smoothing capacitor 2
The voltage of No. 4 is reduced to charge the smoothing capacitor 151, and the charging voltage of the smoothing capacitor 151 is increased in accordance with the increase in the rotation speed of the motor 28.

The operation of the bidirectional power converter 22 for the power supply will be explained. In this mode I, the converter is system-linked to the AC power supply 21 and contains a harmonic current component similar to the voltage waveform of the power supply. It operates as a boost converter in which a current flows so as to decrease the amount, and performs a forward operation in which the smoothing capacitor 24 is charged to a constant voltage. The operation of the control device 100 relating to the above operation will be described with reference to the detailed block diagram of FIG. 4. A PWM control signal 88 for operating as a step-up converter from the O terminal of the power factor correction control IC 36 is sent to the pattern switch 37. Output, the signal 88
And the power supply positive / negative cycle detector 48 has a P terminal which becomes a logic "1" in the positive cycle and an N which becomes a logic "1" in the negative cycle.
The signal output from the terminals is connected to AND gates 89, 90, 91, 92.
The signal obtained by ANDing is output to the data selector 93 such as 74HC158, and the select signal line 94 of the I / OLSI 47 is kept at "0" level in this case, so that the signal of the input terminal A group is output from the Y group terminal. The inverted logic is output, and the gate driver 38 drives the photocoupler 39 via the drive current limiting resistor 95. FIG. 9 shows ON / OFF pulse patterns output from the pattern switch 37 to the switching elements 22U, 22V, 22X, 22Y of the bidirectional power converter 22 for power supply. The photocoupler 39 and the drive circuit for the switching elements are shown in FIG. The same as FIG. 8 which will be described later in detail. The positive cycle refers to the case where the a-terminal of the AC power supply has a high potential and the b-terminal has a low potential in FIG.

Next, the generation of the PWM control signal 88 will be described. The control iC of the power factor correction control iC 36
96 shows an example of using FA5331 manufactured by Fuji Electric Co., Ltd., and as shown in the functional block diagram of FIG.
1 and 4, the same numbers are assigned to the parts having the same functions, and the output of the V sensor 40 is passed through the full-wave rectifier circuit 97 to the V terminal and the voltage of the positive polarity AC power supply 21 serving as a reference. A waveform 177 is given, while the i sensor 41 passes through the full-wave rectifier circuit 98, and the current feedback signal divided by the voltage divider 102 which becomes the divided output of the resistors 99 and 101 is an analog switch 43 such as 74HC4053.
Of the CV1 sensor 42 is input to the YA terminal of the analog switch 43 as a feedback signal and output from the Y terminal. The CV1 sensor 42 converts the voltage-divided output of the smoothing capacitor 24 by the resistors 103 and 123 into a pulse output having a frequency proportional to the voltage by the V / F converter 104, and this signal is output by the photocoupler 1
In 05, the ground level of the signal is insulated, the F / V converter 106 restores the voltage signal proportional to the frequency, and the voltage of the smoothing capacitor 24 is output to the YA terminal of the analog switch 43 while maintaining the insulation. Since the analog switch 43 has the logic level "0" of the select signal line 94 as described above, the XA signal input is transmitted to the X terminal and the YA signal input is transmitted to the Y terminal. The charging voltage of the smoothing capacitor 24 is the resistors 160 and 107, the filter capacitor 1
08 and the operational amplifier 109 compare and amplify the reference voltage 110, and the charging voltage of the smoothing capacitor 24 is, for example, when the voltage of the AC power supply 21 is 100 V, its peak value 1
The voltage is boosted to 170 to 180V which is several tens of volts higher than 41V and kept constant, and the power supply current at that time becomes similar to the power supply voltage waveform. That is, the error signal output VFB from the operational amplifier 109 is multiplied by the power supply voltage V by the multiplier MUL111, and the power supply current i whose polarity is inverted after full-wave rectification indicated by 178 is equal to this multiplication calculation power IiN.
2, 113, capacitors 114, 115 and operational amplifier 1
The output iFB 179 is compared with the sawtooth wave signal 180 of the oscillator 119 composed of the resistor 117 and the capacitor 118 by the PWM comparator 120 by the amplifying action of 16, and is output as a PWM signal from the O terminal. Therefore, for example, when the AC power supply 21 is in a positive cycle, the switching element 22X of the power supply bidirectional power converter 22 is turned on / off in response to the PWM control signal 88 output from the O terminal, so that the reactor 23 and the smoothing device are smoothed. A boost converter is formed in the circuit including the capacitor 24, the charging voltage of the smoothing capacitor 24 is kept constant regardless of the magnitude of the power supply voltage and the load driving the motor 26, and the power supply current is the AC power supply 21. The current waveform is similar to the sinusoidal voltage waveform of and the current flows with almost no harmonic content. FIG. 9 shows ON / OFF patterns of the switching elements 22U, 22V, 22X, 22Y when the bidirectional power converter 22 for power supply is operating in the forward direction. The voltage output of the i-sensor 41 is divided by the voltage divider 102 because the regenerative power is smaller than the power running power due to the loss of the motor 28. Therefore, the i input of the control IC 96 is made large during regeneration to generate a minute regenerative current. On the other hand, this is to reduce the distortion of the power supply current waveform. Reference numeral 121 is a knot gate, and the I / O LSI 47
The output of the data selector and the operation of the control iC96 are enabled by the logical output "0" of the control signal line 122 of.

Next, the operation of the motor inverter converter 26 will be described. The PWM control in the motor inverter converter 26 uses the triangular carrier wave 64 as shown in the example of the waveform of the three-phase PWM inverter shown in FIG. Sine wave signal wave 6
The ON / OFF patterns of the six switching elements 26u, 26v, 26w, 26x, 26y, and 26z that form the inverter are obtained in advance from 5, and the contents thereof are stored in the ROM 29. Eun66, Evn67, Ewn
Reference numeral 68 denotes ON signals of the switching elements 26u, 26v, and 26w, respectively, and conversely, switching elements 26 corresponding to the upper and lower sides
x, 26y, 26z are turned off signals, and euv69, e
vw70 and ewl71 are u of the lines connected to the motor, respectively.
The voltage waveforms output during the v phase, vw phase, and wv phase are shown. FIG. 7 exemplifies the case of 21 carrier duty 50% in the combination of the triangular carrier wave 64 and the sine wave signal wave 65. When changing the number of carriers, use the triangular carrier wave 6
4, which is one cycle of the illustrated sine wave signal wave, from 0 degree to 360 degrees.
It is well known that the amplitude of the sine wave signal wave 65 is changed when the number of cycles to be changed is changed and the duty is changed. The operation of the control device 100 for PWM control will be described with reference to the detailed block diagram of FIG.
The data stored in the OM 29 has the functions of the latch gate drivers 33 and 34, for example, 74HC.
The switching signal 26u, 26v of the bidirectional power converter 26 is driven by the D-type flip-flop such as 374, which is synchronously latched at the CK terminal by the inverted signal 72 of the output signal of the PLL pulse generator 31 to drive the photocoupler 35.
26w, 26x, 26y and 26z are turned on / off. 1
Reference numeral 82 is a knot gate. The data output terminals O1 to O6 of the ROM 29 correspond to 1D to 6D of the latch gate drivers 33 and 34 as shown, and further 1Q to 6Q.
On the other hand, they correspond to u, v, w, x, y, and z, respectively. For example, when the O1 terminal of the ROM 29 becomes the logic "0" level, the latch gate drivers 33, 34 are set to 1 respectively.
Q terminal also becomes logic “0” and LED is turned on through resistor 80.
35 turns on, and the switching element 26u turns on. The OC terminals of the latch gate drivers 33 and 34 switch the output of the Q terminal to high impedance, and the output control line 85 of the I / O LSI 47 has a logic "1".
In the case of, the impedance becomes high and all the photocouplers 35 are turned off. As an example, the drive circuit between the switching element 26u and the photocoupler 35u of the switching element is, as shown in FIG. 8, an appropriate power supply VCCU in which the emitter E of the switching element 26u is set to the reference potential GNDU.
When a current flows through the light emitting diode of the photocoupler 35u, the opposing phototransistor is turned on, the bias of the resistor 74 disappears in the knot gate 75, the output becomes “Hi” level, and the transistor 76 passes through the resistor 76. When a base current flows through 77, a voltage bias is applied to the gate G of the switching element 26u through the braking resistor 78 to turn on the element, and conversely the current of the light emitting diode 35u disappears, the output of the knot gate 75 is similarly output. Turns to the “Lo” level, the electric charge of the gate G is discharged through the transistor 79, and the switching element 26u is turned off. The drive circuit portion is shown at 132. For reading the data from the ROM 29, for example, the counter 30 in which three 74HC193 are connected in three cascades counts up at the rising edge of the pulse output signal 73 of the PLL pulse generator 31, and the signal output from the count terminals Q0 to Q10 is read from A0 to A10 of the ROM 29. In this case, 11 address lines are used to drive the ON / OFF pattern for 360 degrees divided into, for example, 2048 in FIG. 7, and in this case, the latch gate. It is ROM 29 that the drivers 33 and 34 add the latch operation at the rising edge of the inverted signal 72 of the pulse signal 73 of the PLL pulse generator 31.
In the ON / OFF pattern, there is a time lag due to a slight timing shift of the data read output that is read in synchronization with the rising portion of the pulse signal 73 of the PLL pulse generator 31 from O1 to O6 of FIG. This is to prevent a so-called arm short circuit phenomenon in which 26 switching elements in the same arm, for example, 26u and 26x are simultaneously turned on. The CLR terminal of the counter 30 transfers the data of the ROM 29 to the address 0
Is a count clear terminal for reading from the I / O
It is cleared when the control line 86 of the LSI 47 is "Hi". Pulse output signal 7 of PLL pulse generator 31
3 is VC by the PLL element 69 such as 74HC4046.
The timer LSI 32 such as the uPD8253, which is output from the OOUT terminal, divides the oscillation output of the oscillator 51 by the frequency dividing function 32a to obtain the SIN of the PLL element 69 as the reference signal 70.
The pulse output signal 73 of the PLL pulse generator 31 is output to the terminal and the timer LSI 32 divides the pulse output signal 73.
And the CI of the PLL element 69 as the comparison signal 71.
It is output to the N terminal, the error signal is output from the PC terminal by the phase comparator, and the VCO is passed through the low pass filter 81 including a combination of a resistor and a capacitor.
A voltage bypass is given to the IN terminal and is obtained as an oscillation output by the voltage control oscillator VCO 82. An oscillation output having a frequency obtained by multiplying the frequency of the reference signal 70 by the reciprocal of the frequency division ratio of the frequency dividing function 32b is obtained. . The oscillation output of the VCO 82 is 0 to 20 in the case of the ultracentrifuge.
It is necessary to rotate the motor within the range of 0kmin- ¹
Desirably, it is necessary to cover a wide oscillation frequency range of 10 KHZ to 6.9 MHZ, and several kinds of external capacitor capacities of the PLL element 69 are switched and used. One of the capacitors C1, C2, C3, C4 and C5, each of which has one end connected to, is selected from the X terminal and connected to the PLL element 69. Note that the capacitor C0 is always connected so that the oscillation output of the PLL element 69 does not fluctuate greatly while switching the connection of the capacitor. In the mode I, since the rotation speed of the motor 28 is low, the frequency of the pulse output signal of the pulse generator 31 is also low, and the selection signal is sent from the I / O LSI 47 to the CSEL terminal of the analog multiplexer 83 via the capacitor connection switching line signal 84. Is given, and in this case, the capacitor C1 having the largest capacitance is selected.

Next, the operation of the DC power converter 159 will be described. As shown in the functional block diagram of FIG.
In FIG. 1, the parts having the same functions as those in FIG. 1 are designated by the same reference numerals, and the step-down converter IC 156 is Hitachi HA17524.
This is an example of using a well-known DC-DC converter IC such as the above. In order to adjust the charging voltage of 151 by a smoothing capacitor, the feedback signal from the CV2 sensor 152 and the DA / A-DLSI 158 are used. The output charging voltage setting signal 161 is differentially amplified by the error amplifier 162, and the signal output is an oscillator 1 that outputs a sawtooth wave.
The signal output of 63 is compared with the comparator 164, and as a result, the ON / OFF control signal 165 of the switching element 159A of the DC power converter 159 is output from the comparator 164, for example, 74
Step-up / down switch 1 including a data selector such as HC158
It is output to the 1A terminal of 55. Therefore, the above-described step-down converter circuit configured as described above is used in the centrifuge control CPU.
55, I / O LSI 47, DA / A-DLSI 15
8. Control line 166 including bidirectional address / data / control signal line connecting timer LSI 32
The D-A according to the command of the centrifuge control CPU 55.
/ A-DLSI 158 controls the charging voltage of the smoothing capacitor 151 by the analog signal output of the charging voltage setting signal 161, and when the output voltage of the charging voltage setting signal 161 increases, the charging voltage of the smoothing capacitor 151 also increases,
The smoothing capacitor 24 charged to a constant voltage by the forward operation of the power supply bidirectional power converter 22 is used as a power supply, and the voltage of the smoothing capacitor 151 is smoothly started by the motor inverter converter 26 from the stopped state of the motor 28. The voltage can be arbitrarily controlled within a range from the lowest possible voltage to almost the original charging voltage of the smoothing capacitor 24. On the other hand, the step-up converter IC 157 similarly has the same type and the same configuration as the step-down converter IC 156, and in order to boost-adjust the charging voltage of the smoothing capacitor 24, the feedback signal from the CV1 sensor 42 and D- The charging voltage setting signal 167 output from the A / A-DLSI 158 is differentially amplified by the error amplifier 168, and the signal output is compared with the signal output of the oscillator 172 that outputs a sawtooth wave by the comparator 173, and as a result, An on / off control signal 174 for the switching element 159B of the DC power converter 159 is output from the comparator 173 to the 2B terminal of the step-up / down switch 155. Therefore, in the boost converter circuit configured as described above, the charging voltage of the smoothing capacitor 24 is controlled by the analog signal output of the charging voltage setting signal 167 according to the instruction of the centrifuge control CPU 55, and the output voltage of the charging voltage setting signal 167 is controlled. Is increased, the charging voltage of the smoothing capacitor 24 also increases,
As will be described later, in regenerative braking when the motor inverter converter 26 decelerates the motor 28 during reverse operation of the bidirectional power converter 22 for power supply, the DC power regenerated by the motor in the low-speed rotation range. Even if the smoothing capacitor 151 is charged to a low voltage due to, the smoothing capacitor 24 is charged to a sufficiently high voltage by the step-up operation of the DC power converter, and the power regenerated by the power supply bidirectional power converter 22 is It is returned to the AC power supply 21. The analog outputs of the CV1 sensor 42 and the CV2 sensor 152 are supplied to the DA / A-DLSI 158 so that the centrifuge control CPU 55 can monitor the respective voltages of the smoothing capacitors 24 and 151 while performing these controls. Has also been entered.
In the buck-boost switch 155, the DC power converter 1 of FIG.
As shown in the ON / OFF control pattern of the switching elements 159A and 159B in the step-down converter 59 and step-up converter mode, the control output of the I / O LSI 47 causes the select S terminal “1” of the step-up / down switch 155 to change,
The logic of "0" is controlled and the above mode is selected. That is, when the S terminal is "0", 1A, 2A
Since the output of the input terminal of is inverted and output to the 1Y and 2Y terminals, the switching element 159A is controlled by the ON / OFF PWM control signal 165, the switching element 159B maintains the OFF state, and the step-down converter mode is set. When the S terminal is "1", the outputs of the input terminals of 1B and 2B are inverted and output to the 1Y and 2Y terminals, and the switching element 159A is kept in the off state.
9B is controlled by the on / off PWM control signal 174 to enter the boost converter mode. 175 and 176 are resistors for limiting the photocoupler current.

As described above, in the mode I, the power supply bidirectional power converter 22 is system-linked to the AC power supply 21 so that the content of the harmonic current component similar to the voltage waveform of the power supply is reduced. The smoothing capacitor 24 is charged to a constant voltage higher than the peak value of the AC power supply 21, while the DC power converter 159 operates as a step-up converter through which a current flows.
The centrifuge control CPU 55 operates as a voltage variable step-down converter, the charging voltage of the smoothing capacitor 151 is controlled, and the voltage applied to the motor 28 is adjusted by PWM control according to the pulse pattern stored in the ROM 29 of the motor inverter converter 26. And the voltage V of the V / f control is cooperatively performed, and in controlling the frequency f, an appropriate slip frequency f ₁ is given to the motor 28 by the PLL pulse generator, The rotor 27 is gradually accelerated by the slow accelerator along the curve of FIG. In this mode I, the control method for adjusting the actual rotation speed of the motor 28 to the elapsed rotation speed of the rotor 27 shown in FIG.
5 is the step-down voltage V ₁ of the DC power converter 159, the slip frequency f ₁ by the PLL pulse generator 31, and the motor by the PID calculation or the like from the difference between the predetermined number of revolutions of the motor and the current number of revolutions of the motor 28. For the PWM control duty D ₁ of the inverter converter 26 for V / V
It is based on a well-known control method of feedback control for f control.

Next, the mode II of FIG. 5 is a process of rapidly accelerating the rotor 27 to the target settling speed N0, and the bidirectional power converter 22 for the power source operates as a boost converter similar to the mode I and smooths. AC condenser 2 is for AC power supply 2
The DC power converter 159 operates as a step-down converter by being charged to a constant voltage higher than the peak value of 1, and charges the smoothing capacitor 151 to a voltage substantially equal to the original charging voltage of the smoothing capacitor 24. Therefore, in this mode, the V / f control for the motor 28 changes the amplitude of the sine wave signal wave 65, that is, the duty of the voltage applied to the motor stepwise as shown in the example of the waveform of the three-phase PWM inverter in FIG. , V / f is controlled by changing the pattern reading block stored in the ROM 29 for each block, and f is controlled by the frequency dividing function 3 of the timer LSI 32.
The dividing ratio of 2b is successively increased and the capacitors C1 to C5 connected to the PLL element 69 are selected and switched as shown by 181 to give the motor 28 an appropriate positive slip frequency corresponding to the number of rotations thereof, thereby achieving the target settling rotation. Accelerate to a number N0.

FIG. 11 shows the contents of the blocks stored in the ROM 29. The small block n0PWM
This is an example of performing 32-step V control in which 0 is the minimum duty and n0PWM 31 is the maximum duty. On the other hand, the difference between the middle blocks n0PWM and n1PWM is the difference in the number of carriers of the triangular carrier wave 64 in FIG.
The number of switching elements 26u, 26v, 26w, 26 of the motor inverter converter 26 increases as the rotation speed of the motor increases.
Since the switching times of x, 26y, and 26z become improperly too large, it is necessary to properly manage the temperature rise of the element due to the switching loss, and as the rotation speed of the motor 28 increases, the triangular carrier wave 64 The number of carriers is reduced so that the number of carriers in n3 is set smaller than that in n0. Since n3 is used in the high-speed rotation range with respect to n0, the division range of the duty PWM0 to PWM31 is also high. The change of the read block of the small block is selected by the control line 124 connected to the A _{11 to} A ₁₅ line VSEL of the address line of the ROM 29 from the I / OLSI 47 of FIG. Is the I / OLSI4 of FIG.
7 to the control line 125 connected to the A _{16 to} A ₁₈ lines FSEL of the address line of the ROM 29.

FIG. 12 shows VICOOUT7 with respect to the voltage bias VCOIN of the linear scale with C1 to C5 of the capacitor 181 connected to the PLL element 69 in the PLL pulse generator 31 as a parameter regarding the control of f.
The frequency output from 3 is shown on a logarithmic scale. To accelerate and settle the motor from the stationary state to the maximum rotation speed, the capacitors C1 to C2, C3, C
4 and C5 are selected and switched to increase the oscillation frequency of the PLL pulse generator 31. Further, in this case, the oscillation frequency ranges of the capacitors are overlapped with each other, and for example, when accelerating and settling to the above-described maximum rotation speed, it is possible to select and switch between the capacitors C1 to C3 to C5. For example, if the control rotation speed of the motor 28 is between Na and Nb, it shows that the capacitor C2 is selected and the frequency required for f control is output, and if the control settling rotation speed is just Nb. Considering that the target rotational speed is settled with some overshoot of the rotational speed during the acceleration settling, Na to N rather than the actual rotational speed range Na 'to Nb' of the condenser C2 can be covered.
The range of use is limited so that b is on the inside, and in order to suppress the change of VCOIN as much as possible so that an oscillation output with a stable frequency can be promptly obtained when switching the connection of the selected capacitors, the rotational speed range that can cover each other's capacitors. Are sufficiently overlapped. The capacitor is selected by the capacitor connection switching signal 84 of the I / O LSI 47.
Is performed as described above.

In this mode II, the V control of the V / f control is not performed by the PWM based on the pattern data stored in the ROMN 29, but by the voltage output adjusting function of the step-down converter of the DC power converter 159, the smoothing capacitor is used. 15
It is also possible to adjust the charging voltage of unity.

Next, mode IV in FIG. 5 is a process of maintaining the rotor 27 at the target settling speed N0 at a constant level.
Similarly to, the bidirectional power converter 22 for power supply operates as a step-up converter, the smoothing capacitor is charged to a constant voltage, the DC power converter 159 operates as a step-down converter, and is substantially equal to the charging voltage of the smoothing capacitor 24. The smoothing capacitor 151 is charged to the voltage. Then, for example, if the target settling speed N0 is the maximum operating speed of the centrifuge, the small block in the ROM selects n3PWM31 of the maximum duty with the minimum number of carriers, and the PLL element 69.
C5 is selected as the capacitor connected to and a high frequency f is output. The control for keeping the rotation speed of the motor 28 constant at the target settling rotation speed N0 is performed by the centrifuge control CPU 55 performing PID calculation on the difference between the target rotation speed N0 and the current rotation speed of the motor 28. Frequency f
₁ is determined, and the frequency division function 32b of the timer LSI 32 corresponding thereto is instructed to control the frequency division ratio.

Next, mode IV in FIG. 5 is a process in which the rotor 27 is rapidly decelerated by regenerative braking, and the bidirectional power converter 22 for power supply shown in FIG. It operates as a step-down converter so that a current similar to the voltage waveform returns to the power supply, performs reverse operation in which the rise of the charging voltage of the smoothing capacitor 24 is suppressed and the voltage is maintained at a constant voltage. The mechanical energy of the motor 28 is regeneratively converted into electric energy by V / f control of slip frequency control and PWM control,
The smoothing capacitor 151 is charged and the DC power converter 15 is charged.
9 operates as a boost converter, and smoothing capacitor 1
The DC power of 51 is boosted and the smoothing capacitor 24 is charged.

Therefore, even if the rotation speed of the motor 28 decreases and the charging voltage of the smoothing capacitor 151 decreases due to the regenerative braking of the motor 28, the step-up action of the DC power converter 159 causes the smoothing capacitor 24 to operate as a power source. Directional power converter 2
2 is constantly boosted and charged to the voltage capable of regenerating electric power in the AC power supply 21, so regenerative braking can be performed until the motor 28 falls to an extremely low speed rotation region, and mechanical energy of the motor 28 is efficiently regenerated as electric power. It becomes possible.

A bidirectional power converter 2 for a power source will be described with reference to FIG.
The operation of the control device 100 relating to the reverse operation of No. 2 and the above control will be described. Since the select signal line 94 of the I / O LSI 47 is kept at logic "1" in this case, the signal at the input terminal B of the data selector 93 is The signal is logically inverted and output from the Y terminal, and the switching elements 22U, 22V, 22X, 2 of the bidirectional power converter 22 for the power supply are output from the pattern switching converter 37.
The signal of the pattern shown in FIG. 13 is output to 2Y.

The generation of the PWM control signal 88 will be described. Since the S input terminal of the analog switch 43 is also at the logic "1" level, the signal directly input from the i sensor 41 to the XB terminal through the full-wave rectifier circuit 98. Is output from the X output terminal, and the smoothing capacitor 2 is output from the CV1 sensor 42.
The charge voltage signal of No. 4 is applied to the reference voltage 12 by the differential amplifier 45.
The signal subtracted from 6 is input to the YB terminal of the analog switch 43, and the power factor correction control IC 36 is fed from the Y terminal as a feedback signal of the charging voltage of the smoothing capacitor 24.
Entered in. Reference numeral 127 is an operational amplifier in the differential amplifier 45, and 128, 129, 130 and 131 are resistors forming a differential amplifier circuit. When the charging voltage of the smoothing capacitor 24 increases, the output voltage of the differential amplifier 45 decreases. Then, in FIG. 10, if the output of the CV1 sensor 42 is replaced with the output of the differential amplifier 45 described above, the operational amplifier 10
9 is compared and amplified with the reference voltage 110, and the charging voltage of the smoothing capacitor 24 is kept constant at 160 to 170 V when the AC power supply 21 is 100 V, and the current returning to the power supply at that time is controlled by the control IC 96 similar to that described above. The PWM control signal 88 is output by the action. Therefore, for example, when the AC power supply 21 has a positive cycle, the switching element 22Y of the bidirectional power converter 22 for power supply is controlled by the control IC.
It turns on / off in response to the PWM control signal 88 output from the O terminal of 96, and the switching element 22U is kept in the on state in the cycle of this polarity, so that the voltage is lowered in the circuit including the reactor 23 and the smoothing capacitor 24. The converter is formed, and the current regenerated in the AC power supply 21 is similar to the voltage waveform of the AC power supply 21, and a current with almost no harmonic current content that is close to a sine wave flows.

Next, the mode V is a process of gradually decelerating and stopping the rotor 27 from the rotating state to the stationary state in the slow dexel after the rapid decelerating process of the rotor 27 in the mode IV.
Since the rotation speed of the motor 28 is low, the motor 28 is controlled by DC braking instead of regenerative braking to apply a deceleration force to smoothly stop the motor 28. Therefore, the power supply bidirectional power converter 22 operates as a step-up converter to perform forward operation, the DC power converter 159 operates as a step-down converter, and switching elements 26u and 26v of the motor inverter converter 26 for DC braking. , 26w, 26x, 26y, 2
FIG. 14 shows an example of the on / off pattern output to 6z. In order to adjust the braking force, the DC power converter 159 steps down the charging voltage of the smoothing capacitor 24 to the arbitrary voltage of the step-down converter to charge the smoothing capacitor 151, and at the same time, the motor inverter converter 2
6, the level of the comparison signal 146 is changed in correspondence with the triangular carrier wave 145 and the comparison signal 146, and an appropriate PWM duty can be arbitrarily selected.
BPWM0 to PPW stored in ROM 29 at
The middle block of M31 corresponds to the DC braking portion, and 32 levels of duty can be selected. FIG. 14 shows an example in which the number of carriers is 16 and the duty is 40%. In the figure, 26x corresponding to 26v divided by the type of hatching
Alternatively, the element of 26z is turned on to generate a braking force. In Mode V, depending on the type of sample to be centrifuged and the separation conditions, deceleration is performed by a deceleration curve as shown by dexel pattern A, which is more gradual than deceleration by natural deceleration as shown in FIG. At this time, the bidirectional power converter 22 for power supply is operated in the forward direction in the same manner as in Mode I described above, instead of the DC braking described above, and the smoothing capacitor 151 is charged by the step-down converter function of the DC power converter 159. A driving method is used in which the motor 28 is driven by the motor inverter converter 26 while adjusting the voltage, and the motor 28 is gradually decelerated smoothly.

In the description of the embodiments of the present invention, the bidirectional power converter 22 for power supply is described as an example in which it is connected to a single-phase alternating current.
Added V sensor 40, i sensor 41, reactor 2
Those skilled in the art can easily understand that the function can be realized by the similar configuration by providing 3 corresponding to each phase. Further, in the embodiment of the present invention, the free-wheeling rectifier circuit of the bidirectional power converter 22 for power supply, the direct-current power converter 159, and the inverter converter 26 for motor is structurally parasitic on the switching element that constitutes the converter. A rectifier that is present or intentionally built in can be used, or it may be externally configured. Further, it is obvious that the switching element does not depart from the concept of the present invention even if it has a self-extinguishing ability such as a transistor, or if it is configured by adding an appropriate turn-off circuit to an element such as a thyristor. .

In the present invention, the bidirectional power converter for power supply 2
2 and the switching elements 22U, 22V and 26u, 26v, 26 of the upper arm of the inverter converter 26 for the motor
The power supply for the switching control of w is supplied to the switching elements 22X, 26Y and 2 of the lower arms facing each other.
FIG. 16 shows an embodiment in which the control for 6x, 26y, and 26z switching control and the reference potential are shared. FIG.
Shows the case of the motor inverter converter 26, and the portions having the same functions as those in FIGS. 1 and 8 are denoted by the same reference numerals, and the drive circuit 132 of the switching element 26u will be described as an example. Then, 133 is a common power supply that serves as a common control power supply for the drive circuit 132 having the cathode positive line 24b of the smoothing capacitor 24 as the reference potential and the drive circuits 134, 135, 136, 137, 138 of the other switching elements. , A reverse blocking diode 139 and an electric energy for driving the drive circuit 132 are stored, for example, an aluminum electrolytic capacitor 14
0 is connected in series, the other end of the capacitor 140 is connected to the emitter E of the switching element 26u, and the power supply VCCuGNDu of the drive circuit 132 is connected in parallel to both ends of the capacitor 140. Therefore, when the switching element 26x is turned on, the capacitor 140 is charged from the common power source 133 through the route of the diode 139 and the capacitor 140 switching element 26x,
As the switching element 26x is turned off, the capacitor 140
The cathode side of the switching element 26x is in a floating state where the reference potential is different from that of the common power source 133, and the driving electric energy of the drive circuit 132 of the switching element 26u that operates in a complementary pair with the switching element 26x is the capacitor 1.
Stored in 40. Switching elements 26y and 26v,
The same applies to 26z and 26w, and reverse blocking diodes 141 and 142 and capacitors 143 and 144 are respectively connected and configured as shown. As described above, the upper arm drive circuits 132, 134, 13
Since 5 is driven by the charge charged in the capacitors 140, 143, 144, respectively, it is necessary to frequently repeat the on / off operation of the lower arm switching elements 26x, 26y, 26z without stopping. , FIG. 14
The on / off pattern of the DC braking shown in (4) has been devised so as to satisfy the above constraint conditions. Further, in the present invention, the control of f that gives a slip to the motor 28
When the C1 to C5 of the capacitor 181 connected to the PLL element 69 in the pulse generator 31 are selectively switched, the output frequency of the pulse output signal 73 fluctuates transiently due to the time constant of the low pass filter 81, the frequency response characteristic, or the like. Regarding the on / off of the lower arm switching element 26x facing the upper arm switching element 26u in the bidirectional power converter 26, the dead time set so as not to cause an arm short circuit is insufficient at a normal frequency. Occurs, the switching elements of the upper and lower arms may turn on at the same time, causing an arm short circuit phenomenon.
As shown in FIG. 17, when switching the capacitor, when the frequency of the pulse output signal 73 is stable immediately before switching and immediately after switching for a predetermined time, for example, about 200 mSEC.
Across the upper arm switching elements 26u, 26v,
26w are all turned off, while the lower arm switching elements 26x, 26y, and 26z temporarily drive and control the motor inverter converter 26 in a pattern in which switching operations are frequently repeated without pausing. In addition,
This switching pattern is written in the middle block at the position indicated by the ARMPAT 150 in the explanatory view showing the stored contents of the ROM 29 in FIG. The same applies to the bidirectional power converter 22 for the power supply. As shown in FIGS. 9 and 13, it is the lower arm that applies the PWM signal 88 to the switching elements 22X and 22Y of the lower arm during forward operation and reverse operation. This is because the switching operation is frequently repeated without stopping on / off of the switching element. According to the present embodiment, since it is not necessary to provide power sources for the reference potentials of the drive circuits of the upper arm, which are independent of each other, it is possible to simplify the control unit.
As a result, it is effective in downsizing the equipment.

[0034]

According to the present invention, it operates so as to reduce the content of the harmonic component of the current passing through the power supply, and when it is converted from AC power supply to DC power supply, it becomes a boost converter,
Between the DC power supply and the AC power supply for reverse conversion, the power supply bidirectional power converter operates as a step-down converter, and the motor inverter converter that inputs and outputs electric power to and from the DC power supply to drive and regenerate the motor. Via a DC power converter, which operates as a step-down converter when supplying the output of the bidirectional power converter for the power supply to the inverter converter for the motor, and conversely to the converter converter for the motor. When the output is supplied to the bidirectional power converter for power supply, it operates as a step-up converter, so during power running of the motor, the bidirectional power converter for power supply can be operated smoothly while the motor is stopped. In the regenerative braking of the motor, it is possible to start up, and there is an effect that the power can be regenerated to the AC power source even in the low speed rotation region.

[Brief description of drawings]

FIG. 1 is a block diagram showing a specific embodiment of the present invention.

FIG. 2 is an electric circuit diagram showing another embodiment of part of FIG.

FIG. 3 is a block diagram showing a detailed embodiment of FIG.

FIG. 4 is a block diagram showing a detailed embodiment of FIG.

FIG. 5 is an explanatory diagram showing the elapsed time of the rotation speed of the motor.

FIG. 6 is a functional block diagram of a DC power converter.

FIG. 7 is an explanatory diagram showing an example of a waveform of a three-phase PWM inverter.

FIG. 8 is a drive circuit diagram of a switching element.

FIG. 9 is an explanatory diagram of ON / OFF patterns of the switching elements during the powering operation of the bidirectional power converter for power supply.

FIG. 10 is a functional block diagram of a control IC.

FIG. 11 is an explanatory diagram showing storage contents of a ROM.

FIG. 12: VC with the capacitance of the capacitor as a parameter
It is explanatory drawing which showed the relationship of the output frequency with respect to the input bias voltage of O.

FIG. 13 is an explanatory diagram of ON / OFF patterns of switching elements during a regenerative operation of the bidirectional power converter for power supply.

FIG. 14 shows that the DC braking of the three-phase PWM inverter is turned on.
It is an off pattern explanatory view.

FIG. 15 is an explanatory diagram of a deceleration pattern.

FIG. 16 is an embodiment diagram showing a power supply circuit of a drive circuit.

FIG. 17 is an ON / OFF control pattern diagram at the time of switching capacitors.

FIG. 18 is an ON / OFF control pattern diagram of a switching element of a DC power converter.

[Explanation of symbols]

21 is an AC power supply, 22 is a bidirectional power converter for power supply, 26
Is a motor inverter converter, 159 is a DC power converter, and 100 is a controller.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shinji Watanabe 1060 Takeda, Katsuta-shi, Ibaraki Hitachi Koki Co., Ltd. (72) Inventor Tokuyasu Matsufuji 1060 Takeda, Katsuta-shi, Ibaraki Hitachi Koki Co., Ltd. (72) Inventor Yoshinori Tobita 1060 Takeda, Katsuta City, Ibaraki Hitachi Koki Co., Ltd.

Claims (1)

[Claims] 1. A power converter of an AC power supply and a DC power supply, which is system-linked to an AC power supply and operates so as to reduce the content of a harmonic current component of a current passing through the AC power supply. A bidirectional power converter for the power supply that operates as a step-up converter when converting and a step-down converter when converting from a DC source to an AC source, and an inverter converter for a motor that powers and regenerates a motor that inputs and outputs to and from the DC source. In a control device for a centrifuge motor, the output of the bidirectional power converter for power supply provided between the bidirectional power converter for power supply and the inverter converter for motor is used as an inverter for the motor. When it is supplied to the converter, it acts as a step-down converter, and when it supplies the output of the motor inverter converter to the power supply bidirectional power converter, it operates as a step-up converter. Centrifuge, wherein a converter and a control device for controlling the operations of the bidirectional power converter for the power source, the inverter converter for the motor, and the direct current power converter in accordance with the operating state of the motor are provided. Machine motor control device.