JPH03230759A - Power supply device and improving method for power factor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a power supply device that rectifies alternating current power and converts it into direct current, and particularly relates to a power supply device suitable for improving the power factor.

[Prior Art] In a power supply device that uses a rectifier to convert AC power into DC power, the power factor is improved to some extent by using a reactor, but the power supply current contains large harmonics. Therefore, there is a problem that voltage distortion occurs, which adversely affects the power supply system. Therefore, in this type of power supply circuit, it is necessary to suppress harmonics of the power supply current.

In contrast, conventionally, a rectifier circuit that rectifies AC power and converts it into DC power, and is equipped with a circuit that suppresses harmonics of the power supply current, is described in Japanese Patent Application Laid-open No. 198873/1983. There is something.

This is done by connecting a switching element to the output end of the rectifier circuit, and comparing the synchronization error signal, which is the difference between the DC output voltage and the set voltage multiplied by the voltage signal of the AC power supply, with the current waveform, and depending on the polarity of the difference. The above-mentioned switching element is turned on and off.

[Problems to be Solved by the Invention] However, the above-mentioned conventional technology has the following problems, which are problems to be solved in order to obtain a power supply device with improved power factor.

In the above-mentioned conventional technology, an AC current command waveform for power factor improvement is created from an AC voltage waveform. Therefore, a device for detecting the AC voltage waveform is required, which causes problems in that the circuit becomes complicated and large.

Further, in the conventional technique described above, when voltage fluctuation or noise occurs in the AC voltage, the influence directly appears on the current command waveform, so there is a problem in terms of reliability.

The purpose of the present invention is to improve the power factor with a simple circuit configuration without using an AC current command waveform, and to provide a highly reliable power source that is less susceptible to AC voltage fluctuations and noise. The goal is to provide equipment.

[Means for Solving the Problems] In order to achieve the above object, the present invention improves the power factor by using a rectifier circuit that converts alternating current into direct current, a switching operation by a switching element, and an energy storage effect by inductance. In a power supply device equipped with a power factor correction circuit, a power supply current information creation means that generates power supply current information indicating a current flowing through the power supply, and a coefficient is set in accordance with load state information indicating the operating state of the load, and the coefficient is set in accordance with the load state information indicating the operating state of the load. conduction ratio creation means for calculating the product of the current information and the power supply current information, and creating a conduction ratio that defines the operation of the switching element based on the product; It is characterized by operating the element.

Examples of the power supply current information generation means include a power supply current detection circuit. With this, the absolute value of the current flowing through the power supply is detected and the detected value is used. Also,
Another example is a method of estimating the power supply current assuming that it is a sine wave.

Used to set the above coefficients. Information indicating the state of the load includes, for example, the magnitude of the power supply current, the input voltage, the input power from the power supply, the DC output voltage, the required power of the load, and the like.

In the present invention, in order to control the boost ratio to be constant, the coefficient may be determined to be a value that is the reciprocal of the product of the boost ratio and the power supply current.

Further, in the present invention, preferably, a power supply current calculation circuit for calculating the magnitude of the power supply current is provided, and the coefficient is determined to be a value related to the magnitude of the power supply current that is the output of the power supply current calculation circuit.

Furthermore, in the present invention, a configuration may be adopted in which a power supply voltage detection circuit is provided and the coefficient is determined to be a value related to the output of the power supply voltage detection circuit.

Further, according to the present invention, by determining the coefficient to a value related to the switching limit value of the power supply current, it is possible to control the waveform so that no switching operation is performed in the central portion of the half cycle of the power supply current.

In addition, in the present invention, the conduction ratio is calculated by multiplying the coefficient obtained as described above by the information indicating the instantaneous value of the power supply current, and then converting the obtained product into a periodic waveform (for example, a triangular waveform).
It can be created by comparing. Here, a configuration may be adopted in which the triangular waveform is distorted and the magnitude of the conduction ratio is arbitrarily changed.

(The following is a blank space) [Operation] The operation of the present invention will be explained below using the power supply current is and the coefficient K.

First, the OFF conduction ratio x opp of the switching element is created using the following equation.

Xapr": K Hi5 -...
(1) Also, is is the DC voltage E4 and the power supply voltage Vs
is” / (Vll X0FF” EJd
t...It can be expressed as (2). Substituting equation (1) into equation (2) and rearranging it as ■5=V, sinωt, we get 1, ω ・V, 1 − at1
B=L1102+α2(e-CO5ωt+sinωt
)+1°・e−1 ω (3).

here, ■. = initial value of 15, α= to −E4/L be.

Therefore, by inserting the condition that α is sufficiently large and rearranging by setting α)ω and e′″11=0, we get 1, v′ ・si
nωt 1s K-Ed (4).

On the other hand, 1 conduction ratio is ON and the conduction ratio is X. Considering as N, the above equations (1) and (2) can be expressed as follows.

xoN=IK-xs-
(5), 1 x s= / (vs (1xoN)・Ei)
d t - (6) Substituting equation (5) into equation (6), v5
=Vvsinωt, then rearranged to form equation (3), and rearranged by incorporating the same conditions as above, to form equation (4).

From the above, assuming that K and E4 are constant, a sinusoidal waveform synchronized with the power supply voltage can be obtained by giving a 1 conduction ratio according to equation (1) or (5). , the power factor can be controlled to unity.

Further, as shown in equation (4), the power supply current changes depending on the value of K. That is, the input power changes depending on the value of K. The output power (DC voltage x DC current) also changes accordingly. By changing K using this relationship, it becomes possible to control input power and further control output power.

Furthermore, if we transform equation (4), we get vf.

K 0x s = −sxnωt −(
7) It becomes 4. The left side of equation (7) is the OFF conduction ratio shown in equation (1), and the right side is the reciprocal of the instantaneous boost ratio.

Here, if we consider the step-up ratio a on an effective value basis, assuming that the effective value of the power supply current is Is, then K ・Is = 1/ a - (8
), and if K-Is is controlled constant, the DC voltage E,
can be controlled to be a times the power supply voltage.

From the above, by changing the coefficient K, it becomes possible to control the boost ratio a.

Also, the proportionality coefficient K is set to =8. □8 K. is a constant...(9)
If selected as follows, the OFF conduction ratio is xoFr=8. s+is...(10), where 0≦X OFF≦1, and 18≧Ka・I
During the period when s is satisfied, X0FF=1 and the switching operation stops.

From the above, in a region where the power supply current is large, switching can be stopped to reduce switching loss occurring in the switching element and improve efficiency.

The effect described above is for the case where the coefficient K is set based on the magnitude of the power supply current 1s, but it can be considered similarly when it is based on the input voltage, DC high power power, required load power, etc. .

As is clear from the above explanation of the effects, in the present invention,
Power factor improvement can be performed without the need for a sinusoidal current (alternating current) command waveform, which simplifies the circuit configuration and makes it less susceptible to disturbances such as voltage fluctuations and noise. Therefore, a highly reliable power supply device can be obtained.

Further, the present invention is not limited to this, and can also solve various problems as described below.

First, the conventional technology is a device that detects DC voltage and performs DC voltage control.
It indirectly controls the load power.

For this reason, in conventional technology, when attempting to control the power required by a load, a DC voltage command value must be created and current control must be performed using a current command value based on this command value, which requires a circuit configuration. and control becomes complicated. There is also the problem that fluctuations in power supply voltage affect the power factor.

In contrast, the present invention can supply the power required by the load by changing the conduction ratio and changing the size of the input terminal by setting the coefficient K based on the information. ,Wear. Therefore, load power control can be realized without complicating the circuit configuration or control. Furthermore, since the magnitude of the DC voltage changes in accordance with fluctuations in the power supply voltage, load power control can be performed stably without affecting the power factor.

Second, the conventional technology is a system that only considers power factor improvement and ensures a high power factor, but there is a problem of low efficiency.

However, when considering actual power supply circuits, improving efficiency is also an important issue.

On the other hand, there is a method of controlling the DC voltage command value by setting it to a value equal to or lower than the rectified voltage value. This method does not require any additional circuit configuration and can be controlled. But when the power supply voltage fluctuates.

There is a problem that the current waveform changes and the power factor or efficiency decreases.

For example, when the power supply voltage is 100V, the rectified voltage becomes 140V, so the command value is set to 130V.

In this state, when the power supply voltage changes from 100V to 115V, the rectified voltage becomes about 160V, and although the efficiency increases, the current changes from (a) to (b) as shown in Figure 10. A problem arises in that the waveform deteriorates and the power factor decreases.

On the other hand, when the power supply voltage changes to 85V, the rectified voltage increases to 12V.
Since it becomes 0V, which is lower than the command voltage, switching is performed on the entire current waveform, and the waveform changes from the waveform shown in FIG.

As described above, the conventional technology has a problem in that the power factor and efficiency change due to fluctuations in the power supply voltage.

On the other hand, a method can be considered in which a circuit for stopping switching depending on the current value is added to the above-described conventional technique. According to this method, the current waveform can be controlled to be constant, and it is thought that the power factor and efficiency can be controlled stably. However, there is a problem in that a signal generating means for stopping switching is required, making the circuit configuration and control complicated.

In contrast, the present invention aims to improve efficiency by stopping switching at the center of the current waveform.

As a result, although the power factor may decrease slightly, efficiency improves. Therefore, according to the present invention, both power factor and efficiency can be controlled satisfactorily, and the power supply device is highly practical.

Thirdly, in the conventional technology, a current command is created from the DC voltage deviation to control the DC voltage, so there is a problem that the DC voltage cannot be controlled in accordance with the power supply voltage. In contrast, in the present invention, when the power supply voltage fluctuates, the DC voltage changes, and the DC voltage can be controlled in accordance with the power supply voltage.

Further, by determining the coefficient K based on the power supply voltage so as to obtain a desired DC voltage, the DC voltage can also be controlled to a desired constant value.

(The following is a blank space) [Examples] Examples of the present invention will be described below with reference to the drawings.

FIG. 1A is a block diagram showing an example of the configuration of a power supply device according to an embodiment of the present invention.

The power supply device of this embodiment shown in FIG. 1A includes a rectifier circuit 2. It is configured to include a power factor improvement circuit 3 and a smoothing capacitor 4, and a control circuit 30 that controls the power factor improvement and boost ratio to be constant.

The power factor improvement circuit 3 includes a reactor 31, a transistor 33 functioning as a switching element, and a diode 32.
It is composed of:

The output of the AC power supply 1 is converted into a DC voltage Ed via the rectifier circuit 2, reactor 31, transistor 33, diode 32, and smoothing capacitor 4, and supplies power to the load LD.

Control circuit 3 that improves the power factor and controls the step-up ratio at a constant level
0 includes a power supply current detection circuit 5 that detects a power supply current, a conduction ratio creation means 6 that creates a conduction ratio of a switching element,
It is configured to include a low-pass filter 8 that outputs an average value of the power supply current from the output of the power supply current detection circuit 5, and a driver 7.

The power supply current detection circuit 5 is composed of a detection resistor 51 that detects the power supply current, and an absolute value circuit 52 that amplifies the output by a certain factor and takes the absolute value.

The conduction ratio creation means 6 includes a microcomputer 62 that calculates a coefficient K from the output of the low-pass filter 8, a multiplier 61 that multiplies the coefficient by the output of the power supply current detection circuit 5, and a triangular wave A comparator 63 compares the output of the multiplier 61 with the triangular wave to create a conduction ratio for the transistor 33.

Although not shown, the microcomputer 62 includes, for example, a CPU that executes data processing, and a ROM that stores programs executed by this CPtJ and various constants.
, RAM for temporarily storing data, etc., and A/D and D/A for sending and receiving data and signals to the outside.
and an interface that performs various conversions. The ROM stores, for example, a program as shown in FIG. 2A for executing the process of calculating the coefficient K, together with constants such as the boost ratio a. The microcomputer 62 will execute the following processes 1 to 3 according to this program.

In process 1, the magnitude of the power supply current S is input into the microcomputer 62.

In process 2, a coefficient K that makes the boost ratio constant based on the effective value of the power supply current is calculated using the magnitude 1 s of the power supply current and the boost ratio a given in advance. Specifically, it is determined by Is. Here, Ka is a conversion coefficient for calculating the effective value from Is.

In process 3, the coefficient K is output to the multiplier 61.

The microcomputer 62 can improve the power factor and control the boost ratio to be constant by repeatedly executing the above boost ratio constant control process every power cycle.

Next, the operation of this embodiment will be explained with reference to FIG. 1B, FIG. 2A, and FIG. 2B in addition to FIG. 1A.

The control circuit 30 sets the conduction ratio according to a first-order arithmetic expression, and controls the transistor 33 on and off via the driver 7.

The resistance value of the detection resistor 51 is R, the amplification factor of the absolute value circuit 52 is N, the power supply current is J, L, and the OFF conduction ratio command value 11 is V.
If XOFF, VXopp = K- □'R' l s
−(11).

At this time, if the maximum value of the OFF conduction ratio command value is selected to be equal to the maximum output value V8 of the triangular wave oscillator 64, the conduction ratio becomes X.

F, becomes as follows.For the reason mentioned above, the power supply current has a sinusoidal waveform, and the power factor can be controlled to approximately 1.

Furthermore, by changing the coefficient K, the boost ratio can be controlled.

In this control circuit 30, a microcomputer 62
works like this:

First, an alternating current 18 supplied from an alternating current power source 1 is detected via a resistor 51, converted into an absolute value by an absolute value circuit 52, and then passed through a low-pass filter 8 to an average value I.
It is sent to the microcomputer 62 as s. The microcomputer 62 takes in the magnitude Is of Is as digital data (step 201).

Next, the microcomputer 62 determines whether or not to perform power factor improvement based on an instruction from the outside (step 202). This external instruction is performed using, for example, a switch (not shown), which is turned on by the operator in advance or as needed.

When performing power factor improvement, the microcomputer 62 sets Is to a preset value, for example.

It is determined whether it is equal to or greater than IA (step 203).

If the set value is exceeded, a Ia is calculated using the boost ratio a and conversion coefficient Ka given in advance (step 203). Then, the calculation result K is D/A converted and output to the multiplier 61 (step 205).

Further, the prohibition of switching of the transistor 33 is canceled for the driver 7 (step 206).

On the other hand, if the determinations in steps 202 and 203 are negative, the driver 7 is instructed to prohibit switching of the transistor 33 (switching 0FF) (step 207). Then, the coefficient K is set to the maximum rFFJ and output (step 208). After this, the process returns to step 201.

Note that the processes in steps 207 and 208 are also executed when an overcurrent is detected. This overcurrent is detected by a detection circuit (not shown), and a detection signal is sent to the microcomputer 62 from this circuit. When this detection signal is sent, the microcomputer 62 generates an interrupt and executes steps 207 and 208 described above. In the case of interrupt processing, the process does not return to step 201.

This process ends.

Note that step 208 (step 4 in FIG. 4B, which will be described later)
07), the reason why K is set to the maximum is to ensure safety in the event that switching is not prohibited for some reason. Therefore, this step can also be omitted.

The above calculated K is multiplied by the power supply current detection value 1151 in the multiplier 61, and the product is sent to the comparator 63 as the OFF conduction ratio command value. The comparator 63 compares this product with the output of the triangular wave oscillator 64 to create a duty ratio.

FIG. 1B shows waveforms at various parts of the control circuit 30.

As is clear from comparing (a) and (b) in the same figure, the OFF duty ratio (auty) signal differs depending on the magnitude of WIK, and as a result, the waveform of the power supply current is also changes. I understand.

As described above, according to this embodiment, since an alternating current command waveform for power factor improvement is not required, a current command waveform generating means is not required, and the circuit can be simplified.

Further, since the step-up ratio can be controlled to be constant, the DC voltage can be controlled to a voltage value corresponding to the input voltage without detecting the DC voltage or the like.

Next, a second embodiment of the present invention will be described with reference to FIGS. 3A and 3B.

The embodiment shown in FIG. 3A is different from the embodiment shown in FIG. 1A in that the conduction ratio creating means 6 is configured by hardware instead of using a microcomputer. The configuration is similar to that of the embodiment shown in FIG. Therefore, only the differences will be explained here.

The conduction ratio creating means 6 used in this embodiment is OF
It is configured to include a multiplication/division circuit 65 that creates the F duty ratio command value 11, a triangular wave oscillator 64, and a comparator 63 that compares the OFF duty ratio command value 11 and the triangular wave.

The conduction ratio generating means 6 includes a logarithmic conversion circuit 651 that logarithmically converts the detected power supply current value lis, a logarithmic conversion circuit 652 that logarithmically transforms the magnitude S of the average value of the power supply current, and A logarithmic conversion circuit 653 that logarithmically converts the conversion coefficient Ka to be converted into a value, a conversion coefficient setter 654 that sets the conversion coefficient Ka, and each of the logarithmically converted signals, log I i s I + log Ka - 1 log I
an adder/subtractor 655 that executes the operation ss; and the adder/subtractor 6
Anti-logarithmic conversion circuit 656 that performs anti-logarithmic conversion on the calculation result of step 55.
It is composed of:

Note that the conduction ratio creating means 6 specifically includes, for example, the third
It can be configured using a multiplication/division circuit 65 having a circuit configuration as shown in FIG.

The operation of this embodiment is as follows, except that the OFF conduction ratio command value 11 is calculated by the analog calculation of the multiplication/division circuit 65.
This is similar to the embodiment shown in FIG. 1A above. Therefore, the explanation will not be repeated here.

Note that, according to this embodiment, the conduction ratio creating means 6 can be constructed at low cost.

Next, a third embodiment of the present invention will be described with reference to FIGS. 4A and 4B.

The present embodiment differs from the other embodiments described above in the configuration of the control circuit in that the coefficients are calculated based on the power command value from the load. In addition.

The other configurations are the same as the first embodiment described above, so
Here, only the differences will be explained.

The control circuit 30 of this embodiment includes a power supply current detection circuit 5, a conduction ratio creation means 6, and a driver 7.

The conduction ratio creation means 6 includes a multiplier 6 that multiplies the power supply current detection value 1i, 1 and a coefficient to output an OFF conduction ratio command value 11.
1, a microcomputer 62 that calculates the coefficient K based on the power command value 13 from the load, and a triangular wave oscillator 64
and a comparator 63 that compares the OFF conduction ratio command value and the triangular wave and outputs the conduction ratio.

The microcomputer 62 has the following hardware:
Although not shown, the structure is substantially similar to that shown in FIG. 1A described above. That is, cpu.

It has ROM, RAM, interface, etc.

This microcomputer 62 operates according to the program stored in the ROM, for example, as shown in FIG. 4B.

First, the power command value P from the load LD! is taken in as a digital value via the interface (step 401
). Then, it is determined whether Pd is greater than or equal to a preset minimum value (step 402).

If it is above the minimum value, perform the calculation (step 403), convert the calculation result K into an analog value, and output it to the multiplier 61 (step 4
04).

If the driver 7 prohibits switching of the transistor 33, this is canceled (step 405).

On the other hand, in step 402, if Pd is not equal to or higher than the minimum value, a signal for prohibiting switching of the transistor 33 is output to the driver 7 (step 40
6). Then, the coefficient K is maximized and output (step 407).

In this way, the present embodiment controls the switching element to change the magnitude of the input current based on the power required by the load. Therefore, according to this embodiment, it is possible to perform load power control that can stably supply the necessary power to the load with a simple circuit configuration without requiring a DC voltage detection circuit, and it is also possible to perform load power control that can stably supply the power necessary for the load. Similarly, the power factor can be improved.

Next, as a fourth embodiment, the present invention is applied to speed control of a synchronous motor whose load is a compressor.
This will be explained with reference to FIGS. 5, 6 and 7.

This embodiment includes a rectifier circuit 2 that rectifies an alternating current from an alternating current power supply 1, a power factor correction circuit 3, a smoothing capacitor 4, and an inverter 15 that supplies driving power to a synchronous motor 21 that drives a compressor 22. , and a control circuit 300.

The AC power supply 1 includes a rectifier circuit 2, a reactor 31, a transistor 33 . It is converted into a DC voltage Ed via the capacitor 4, supplies DC power to the inverter 15, and drives the synchronous motor 21.

Control circuit 300 for controlling the speed of synchronous motor 21
includes a microcomputer 17, a position detection circuit 18 for detecting the magnetic pole position of the synchronous motor 21 from the motor terminal voltage 23, an inverter driver 16 for driving the inverter 15, and a power supply current detection circuit for detecting and amplifying the power supply current. The circuit 5 and the transistor 33 which is a switching element
and a current flow ratio creation means 24 for creating the current flow ratio.

The configuration and operation of the power supply current detection circuit 5 are similar to those of the first embodiment of the present invention shown in FIG.

The conduction ratio generating means 24 includes a D/A converter 241 with a multiplication function, a triangular wave oscillator 243, and a comparator 242.
It is composed of:

Although not shown, the microcomputer 17 includes a CPU, ROM, RAM,
It is configured with an interface etc. Note that in this embodiment, since the D/A converter 241 is provided, the interface of the microcomputer 17 does not need to have a D/A converter function.

The ROM of the microcomputer 17 stores various programs necessary to drive the synchronous motor 21, for example,
Taking in the position detection signal 19 and speed command 20 from the position detection circuit 18, outputting an inverter drive signal to the inverter driver 16, calculating a coefficient, outputting the coefficient to the D/A converter 241 with a multiplication function, etc. Programs related to processing are stored. The CPU executes these processes.

The position detection circuit 18 detects the position of the magnetic pole from the terminal voltage of the motor 21 and outputs a position detection signal shown in FIG. The state of the three-phase signal of this position detection signal changes every 60 degrees.

The microcomputer 17 measures the time t1 to t every 60° with respect to the position detection signal 19, and detects the speed of the synchronous motor 21 by determining the time T of one cycle.

FIG. 7 shows the contents of the speed control process executed by the microcomputer 17, and shows the contents of the speed control process executed by the microcomputer 17.
It shows the procedure for creating coefficients that are output to the A converter 241.

In process 1, the microcomputer calculates the command speed N based on the speed command 20 given from the outside,
In process 2, the time T for one cycle of the position detection signal 19 is determined, and in process 3, the speed N is calculated from the time T for one cycle and the proportionality constant Ky.

In process 4, the microcomputer 17 calculates the deviation speed ΔN=N*- between the speed command N and the detected speed N.
From N, a proportional term P and an integral term I are created, and the DC power command Pd1 is obtained from the sum thereof. Here, the proportional term P is the product of the proportional gain Kp and the deviation speed ΔN, and the integral term I is created by adding the product of the integral gain Ki and the deviation speed ΔN to the integral term at that point.

In process 5, the DC power command Pd and the proportionality constant Kd
The coefficient K is further determined by . In process 6, the coefficient K is output to the D/A converter with multiplication function 241.

By repeatedly executing the above speed control processing, the coefficients are modified until the speed command N 1 and the detected speed N become equal, and the speed of the synchronous motor 21 can be controlled.

(Left below) Next, a fifth embodiment of the present invention will be described with reference to FIGS. 8 and 9.

The embodiment shown in FIG. 8 includes a rectifier circuit 2 for rectifying alternating current from an alternating current power supply 1, a power factor correction circuit 3, a smoothing capacitor 4, and a control circuit 30. This embodiment has the same configuration as the first embodiment described above, except for the configuration of the control circuit 30.

Therefore, the following explanation will focus on the differences.

The control circuit 30 of this embodiment includes a current detection circuit 9, a zero point detection circuit 10 that detects a zero point as a synchronization signal synchronized with the cycle of the power supply, a conduction ratio creation means 14, and a driver 7. Ru.

The power supply current detection circuit 9 includes a detection resistor 9 that detects the power supply current.
1 and a filter circuit 92 that outputs the magnitude of the power supply current from its output. The zero point detection circuit 10 detects the switching point of the polarity of the power supply from the power supply voltage,
It is a circuit that outputs a pulse at that point.

The conduction ratio creation means 14 is constituted by a microcomputer, and has a CPU, ROM, RAM, interface, etc. A program for creating a conduction ratio based on the magnitude and zero point of the power supply current is input to the ROM, for example.

FIG. 9 shows a process executed by the conduction ratio creation means (hereinafter also referred to as a microcomputer in this embodiment) 14.
The contents of the process for improving the power factor and controlling the boost ratio to be constant at the same time, that is, the procedure for creating the conduction ratio will be shown.

In process 1, the magnitude S of the power supply current is input into the microcomputer 14.

In process 2, a coefficient K is calculated from a Is based on the magnitude Is of the power supply current and the step-up ratio a given in advance. Here, Ka is a conversion coefficient for calculating the effective value from the value S.

In process 3, based on the magnitude Is of the power supply current, the power supply current is assumed to be a sine wave, and an estimated power supply current value Is' is calculated.

In process 4, a conduction ratio sequence for the power supply period is calculated using the estimated power supply current value Is' and the coefficient.

In process 5, the zero point of the power supply is taken into the microcomputer 14 using a detection pulse from the zero point detection circuit 10.

In process 6, the conduction ratio sequence calculated in process 4 is output based on the pulse signal at the zero point.

By repeating the above process every power cycle, it is possible to improve the power factor and control the boost ratio to be constant.

Note that the zero point detection circuit may be a circuit that detects a switching point of the polarity of the power supply from the power supply current and outputs a pulse at that point. In this case, when the power supply current is small, it is not easy to accurately determine the zero point, so until the current reaches a certain value, the function that outputs an appropriate position as the zero point is
It is advisable to provide it in the zero point detection circuit.

Further, the conduction ratio generating means 14 may be configured to output a certain constant value of conduction ratio and operate the switching element until the zero point detection circuit can detect the zero point of the power supply.

The present invention is not limited to the embodiments described above, and can be implemented in various other forms. Some examples are shown below.

Among the above embodiments, in those in which the coefficient K is set using the magnitude Is of the power supply current, DC output power may be used instead of the current.

In this case, for example, a power detector is provided after the smoothing capacitor, and the detected value is inputted to the current conduction ratio generating means as information indicating the state of the load.

The conduction ratio creation means is configured to use the output power value to calculate the coefficient K using an algorithm similar to the above-mentioned algorithm when using the magnitude of the current.

Similarly, the coefficient K may be set using the power supply voltage instead of or in addition to the magnitude of the power supply current as information indicating the state of the load. In this case, for example, a power supply voltage detection circuit is provided, the detected value is input to the current flow ratio creation means, and the coefficient K is calculated using the voltage or the current and the voltage. The configuration is as follows. This provides a power supply device that controls output of a DC voltage at a constant ratio depending on the power supply voltage.

Next, in each of the above embodiments, an example is shown in which the boost ratio is controlled to be constant, but the boost ratio may be changed.

In this case, the step-up ratio that improves the power factor and provides the desired output without reducing efficiency is determined in advance by experiment or simulation according to the power supply current and power supply voltage, and this is stored in ROM, etc. However, the coefficient K is calculated using an appropriate step-up ratio depending on the state of the input current and the like.

Note that a configuration may be adopted in which a power supply voltage detection circuit is provided and the step-up ratio is set according to the detected voltage so that the output voltage is set to a desired value. That is, the configuration is such that the DC voltage is controlled by determining a coefficient using the output of the power supply voltage detection circuit so as to obtain a desired DC voltage.

In addition, in each of the above embodiments, the value of the coefficient.

When the power supply current or output power exceeds a preset limit value, the conduction ratio can be determined to be a value that turns off the operation of the switching element. For example, the program is set to determine the value of the coefficient so that the on-current ratio becomes 0 when the power supply current exceeds the limit value.

As a result, switching operation is stopped in areas where the power supply current is large, and switching operation is performed in areas where the power supply current is small, controlling the center part of the half cycle of the power supply current to a waveform in which no switching operation is performed, and improving the power factor and efficiency. can be improved.

Furthermore, in each of the above embodiments, the power factor and efficiency are improved by distorting the output of the triangular wave oscillation circuit in the conduction ratio generating means and arbitrarily increasing or decreasing the conduction ratio. It is also possible to adopt a configuration in which control is performed.

Further, other periodic waveforms may be used instead of the triangular wave.

In addition, the present invention can be configured to control the DC voltage to be lower than the power supply voltage by changing the step-up ratio.

The power supply devices of each of the embodiments described above can each be configured as an electrical device by connecting a DC load to its output or connecting an AC load via an inverter or the like.

Examples of the former include computers, communication equipment, measuring instruments,
Examples include electronic devices such as control devices, plating devices, and the like.

Examples of the latter include power generation and substations, industrial equipment, and household electrical equipment such as inverter air conditioners.

[Effects of the Invention] According to the present invention, it is possible to improve the power factor with a simple circuit configuration without using an alternating current command waveform. Further, it is possible to realize a highly reliable power supply device that is less susceptible to voltage fluctuations and noise of the AC power supply.

Furthermore, according to the present invention, the following effects can be expected as additional effects.

Since the step-up ratio can be controlled to be constant, the DC voltage can be controlled to a voltage value corresponding to the input voltage without detecting the DC voltage or the like.

Furthermore, since the step-up ratio can be controlled, the period during which the switching operation is stopped can be set, and efficiency can be improved.

[Brief explanation of drawings]

FIG. 1A is a block diagram showing an example of the configuration of a power supply device according to the first embodiment of the present invention, FIG. 1B is a waveform diagram showing the operation of the above embodiment, and FIG. 2A is a block diagram showing the operation of the above embodiment. FIG. 2B is a block diagram showing an overview of the calculation process, FIG. 2B is a flowchart showing the calculation operation for coefficients in the above embodiment, and FIG. 3A is a block diagram showing an example of the configuration of a power supply device according to the second embodiment of the present invention. , FIG. 3B is a circuit diagram showing an example of the configuration of the multiplication/division circuit 65 suitably used in the second embodiment, and FIG. 4A is a circuit diagram showing an example of the configuration of the power supply device according to the third embodiment of the present invention. The block diagram and FIG. 4B are flowcharts showing the calculation operation for the coefficients in the third embodiment, and the fifth section shows the fourth embodiment of the present invention, which is an embodiment in which the present invention is applied to speed control of a synchronous motor. A block diagram showing an example of the configuration, FIG. 6 is a waveform diagram showing a position detection signal of the position detection circuit used in the fourth embodiment, and FIG. 7 is a processing content of speed control of the microcomputer in the fourth embodiment. FIG. 8 is a block diagram showing an example of the configuration of a power supply device according to the fifth embodiment of the present invention, and FIG. 9 is a block diagram showing an example of the configuration of a power supply device according to the fifth embodiment of the present invention. Block diagram showing the procedure for creating conduction ratio, No. 10
1 and 11 are waveform diagrams showing power supply current waveforms in a conventional power supply device. DESCRIPTION OF SYMBOLS 1... AC power supply, 2... Rectifier circuit, 3... Power factor correction circuit, 4... Smoothing capacitor, 5... Power supply current detection circuit, 6.14... Conductivity ratio creation means, 8... Low pass filter, 9... Power supply current detection circuit, 10... Zero point detection circuit, 15... Inverter, 21... Synchronous motor, 30... Control circuit, 31... Reactor, 3
2...Diode, 33...Transistor, 61...
... Multiplier, 62 ... Microcomputer, 63.
...Comparator, 64...Triangular wave oscillator, 65...
・Multiplication/division circuit. Figure 3B Figure 4B Figure 6 Figure 11 Cycle 7% Figure Process 1 Figure 10 (a) (a) (b) (b)

Claims (1)

[Scope of Claims] 1. A power supply device comprising a rectifier circuit that converts alternating current to direct current, and a power factor improvement circuit that improves the power factor by using switching operations by switching elements and energy storage effects by inductance, comprising: A power supply current information generation means that generates power supply current information indicating the current flowing in the a current conduction ratio creating means for creating a current conduction ratio that defines the operation of the switching element based on the product, and the power supply device is configured to operate the switching element based on the current conduction ratio. . 2. In a power supply device equipped with a rectifier circuit that converts alternating current into direct current, and a power factor correction circuit that improves the power factor by utilizing the switching operation of switching elements and the energy storage effect of inductance, the power supply current is detected. A coefficient is set according to the detection circuit and the load state information indicating the operating state of the load, and the product of this coefficient and the above power supply current is calculated, and based on this product, the current flow is determined to regulate the operation of the switching element. What is claimed is: 1. A power supply device comprising: a current conduction ratio creating means for creating a current conduction ratio, and is configured to operate the switching element based on the current conduction ratio. 3. In a power supply device that is equipped with a rectifier circuit that exchanges alternating current into direct current, and a power factor improvement circuit that improves the power factor by using the switching operation of switching elements and the energy storage effect of inductance, synchronization that synchronizes with the cycle of the power supply. A synchronous signal detection means for detecting the signal and a coefficient are set according to the load status information indicating the operating status of the load, and the power supply current is estimated, and the product of this coefficient and the estimated power supply current value is calculated. Based on the product, create a conduction ratio series that defines the operation of the switching element,
and a conduction ratio generating means for outputting the generated conduction ratio series based on the synchronization signal detected by the synchronization signal detection means, and configured to operate the switching element according to the conduction ratio. A power supply device characterized by: 4. The power supply device according to claim 1, 2 or 3, wherein the coefficient is set based on the product of the load state information and the boost ratio. 5. The power supply device according to claim 2, 3 or 4, further comprising a function of determining the magnitude of the power supply current from the output of the power supply current detection circuit and setting a coefficient using the magnitude of the power supply current as load state information. 6. The power supply device according to claim 2, 3 or 4, further comprising means for detecting output power, and a function of setting a coefficient using the detected value as load state information. 7. The power supply device according to claim 2, 3 or 4, further comprising a function of setting a coefficient using a power command value from the load as load state information. 8. Claim 2, further comprising a means for detecting a power supply voltage, and a function of setting a coefficient using the detected value as load state information.
, 3 or 4. The power supply device according to . 9. Claims 3, 4, 5, 6, and 7, wherein the synchronization signal detection means includes a zero point detection circuit for detecting a zero point of the power supply current.
or the power supply device described in 8. 10. The power supply device according to claim 4, 5, 6, 7, 8, or 9, wherein the coefficient is set to keep the boost ratio constant. 11. Claims 1 and 2, further comprising a function of setting the coefficient so that when the power supply current or output power exceeds a preset limit value, the conduction ratio becomes a value that turns off the operation of the switching element. , 3, 4, 5, 6, 7 or 8. 12. The power supply device according to claim 8, wherein the coefficient is set using the detected value of the power supply voltage so as to obtain a desired DC voltage. 13. In a power factor improvement method for a power supply device that improves the power factor by using the switching operation by a switching element and the energy storage effect by inductance after converting alternating current to direct current, load status information indicating the operating status of the load and boosting voltage are provided. Calculate a coefficient based on the product with the ratio, multiply this coefficient by information indicating the instantaneous value of the power supply current, compare the obtained product with the periodic waveform to find the conduction ratio, and calculate the conduction ratio. A method for improving the power factor of a power supply device, comprising controlling the switching operation of the switching element accordingly. 14. In a power supply device comprising a rectifier circuit and a smoothing circuit that convert alternating current to direct current, and a power factor improvement circuit that improves the power factor by using the switching operation of a switching element and the energy storage effect of inductance, the output of the smoothing circuit an inverter is connected to the inverter, an electric motor is connected to the output of the inverter, and means for detecting speed information of the electric motor is provided, and means for setting a coefficient based on the speed information, and a power source for detecting a power supply current. Find the product of the current detection circuit, the above coefficient, and the power supply current, and based on this product,
A power supply device comprising a current conduction ratio creating means for creating a current conduction ratio that defines the operation of the switching element, and is configured to operate the switching element based on the current conduction ratio. 15, Claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 1
13. An electrical device comprising the power supply device according to 0, 11 or 12, and a load driven by the DC output of this power supply device. 16, Claims 1, 2, 3, 4, 5, 6, 7, 8, 9, 1
13. An electrical device comprising: the power supply device according to No. 0, 11 or 12; an inverter that converts DC output of the power supply device into AC; and a load driven by the output of the inverter.