JP2836664B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner provided with a control device for controlling a compressor by inverter control by vector control.

[0002]

2. Description of the Related Art In recent years, an air conditioner that controls the capacity by increasing or decreasing the number of revolutions of a compressor using an inverter device that varies the frequency of a power supply has been used.

As an inverter control method for a general-purpose inverter, vector control is often employed because excellent responsiveness and power saving can be obtained. Therefore, in recent years, vector control has also been applied to a variable speed control method for a compressor of an air conditioner.

The vector control method includes a magnetic flux detection type vector control method for detecting a secondary magnetic flux as a vector quantity and using the control signal for a primary current, and a slip frequency type vector for calculating and controlling a magnetic flux vector based on a motor constant. Control schemes are known.

As a conventional technique, for example, Japanese Patent Laid-Open No.
There is one disclosed in Japanese Patent No. 202387.

An example of the operation of the prior art will be described below with reference to the drawings with reference to FIGS. 15, 16, 17, 18, and 19. FIG.

FIG. 15 is a configuration diagram of a conventional air conditioner. FIG. 16 is a block diagram of a slip frequency type vector control device which is an inverter device of a conventional air conditioner.

FIG. 17 is a block diagram showing the configuration of the torque current calculator 27 shown in FIG. FIG. 18 is a block diagram showing the configuration of the slip frequency calculator 35 of FIG.

FIG. 19 is a block diagram of a magnetic flux detection type vector control device which is an inverter device of a conventional air conditioner.

[0010] In Fig. 15, 1 is a compressor, 2 is a four-way valve, 3 is an indoor heat exchanger, 4 is a decompression device, and 5 is an outdoor heat exchanger. ing.

Reference numeral 6 denotes an indoor fan, and 7 denotes an outdoor fan.
Reference numeral 8 denotes an inverter control device for controlling the rotation speed of the compressor 1, and reference numeral 9 denotes a three-phase AC power supply. That is, 10 is an indoor unit, and 11 is an outdoor unit.

Hereinafter, two types of inverter control devices will be described with reference to FIGS. 16, 17, 18 and 19. FIG.

FIG. 16 shows a conventional slip frequency type vector control device. The compressor 1 is supplied with AC power of a variable frequency by the power converter 13, and receives a primary current ia of the compressor 1.
1, ib1 and ic1 are detected by the current detectors 39, 40 and 41, and the rotation frequency ωR is picked up by the speed detector 14 for calculating the speed.

The secondary magnetic flux command φ2 * is supplied to the exciting current calculator 26.
, The torque command τ * is converted into a torque current command iq1 * by the torque current calculator 27 and the secondary resistance R2 * of the motor input thereto.
The excitation current command id1 * and the torque current command iq1 * are converted by the vector rotator 28 into a current value i1 * and a phase angle θ * on the rotating magnetic flux coordinate axes (d, q axes).

On the other hand, using the torque current command iq1 *, the secondary magnetic flux command φ2 *, and the secondary resistance R2 * of the motor, the slip frequency calculator 35 generates a slip frequency command ωs *, and generates a rotation frequency ωR and a slip frequency command ωs. *, That is, a primary frequency ω1 is created. Further, the primary frequency ω1 is integrated by the integrator 36 to obtain the phase angle φ1 * of the rotating coordinate axis, and the adder 34 calculates the sum θ1 * with the phase angle θ * on the dq axis.

Here, the adder 34 performs an operation according to (Equation 1).

[0017]

(Equation 1)

[0018] θ1 * obtained by (Equation 1) is the position of the current as viewed on the stationary axis. The absolute value i1 * of the primary current is a combined current of the exciting current component and the torque current component, and the phase angle θ
1 * indicates the position on the two stationary axes. Therefore, 2 phase-3
The phase converter 29 converts the absolute value i1 * of the primary current and the phase angle θ1 * of the primary current into two-phase and three-phase, and three-phase current command ia
1 *, ib1 *, ic1 *, and comparators 30, 31, 3
2, the output currents ia1, ib1, ic of the power converter
Compare with 1.

In the subsequent current control, the controller is controlled by a normal proportional-type controller or a controller that uses both proportional and integral functions so that the actual current matches the command current.

Vector control becomes possible by the above method. The slip frequency command ωs * is calculated by the slip frequency calculator according to (Equation 2).

[0021]

(Equation 2)

In equation (2), R2 * is a secondary resistance, L
2 * indicates a secondary inductance, and M * indicates a mutual inductance.

FIG. 17 shows the configuration of the torque current calculator 27. A signal output from the torque command τ * through the coefficient units 15 and 16 and the differentiator 19 and a signal output only through the coefficient unit 15 are generated, and these signals are added by the adder 20 to generate the torque current command iq1 *. Is output.

FIG. 18 shows the configuration of the slip frequency calculator 35. The torque current command iq1 * is converted into coefficient units 15 ', 16'
Is output by the divider 17 to the secondary magnetic flux command φ.
It is divided by 2 *, passes through the coefficient unit 21, and receives the slip frequency command ω
s * is output.

When the torque current command iq1 * and the slip frequency command ωs * are calculated as described above, the secondary resistance R2 * is directly involved, but in the conventional vector control method, the secondary resistance R2 * is fixed. Control was performed as.

FIG. 19 shows an example of the vector control system of the magnetic flux detection type.
1, vc1 and the primary currents ia1, ib1, ic1 detected by the current detectors 39, 40, 41, respectively, are obtained by calculation in the magnetic flux calculator 24.

The outputs of the magnetic flux calculator 24 are the stationary two-axis components φα1 and φβ1 of the secondary magnetic flux vector, and the vector analyzer 25 outputs the absolute value component | φ2 |
are converted to φ and cos φ.

On the other hand, the secondary magnetic flux command φ2 * and the generated torque command τ * are processed by the exciting current calculator 26 and the torque current calculator 27, and the exciting current command id1 in the rotating coordinate system considering the rotating magnetic flux on the d axis. *, The torque current command iq1 *, and the vector rotator 28 processes the excitation current command id1.
*, Converts the torque current command iq1 * into current commands iα1 *, iβ1 * in the stator coordinate system based on the phase angle φ.

That is, the output iα1 of the vector rotator 28
*, Iβ1 * are currents for producing the secondary magnetic flux components φα1, φβ1, and are converted by the two-phase to three-phase converter 29 to perform primary current commands ia1 *, ib1 *, ic1 * of the power converter 13.
And the comparison is performed by the comparators 30, 31, and 32, and the output current of the power converter 13 is controlled.

In the magnetic flux detection type vector control system, since the magnetic flux is directly controlled by giving a current command, there is no need for the secondary side inductance or resistance which has the most uncertain elements in the motor constant.

Therefore, even if the constants of the primary circuit and the secondary circuit of the motor inside the compressor 1 change, the input primary voltages va1, vb1, vc1 of the magnetic flux calculator 24 and the input primary current ia
1, ib1, ic1, and the calculation result of the magnetic flux changes accordingly. Therefore, the deterioration of the vector control characteristics due to the change of the parameter is small.

However, estimating the magnetic flux with the magnetic flux calculator 24 and the vector analyzer 25 has many problems in the accuracy and resolution of the sensor, and in particular, there is a problem in the calculation accuracy due to the voltage distortion at low speed, and cannot be performed. Is the actual situation.

[0033]

In the slip frequency type vector control configured as described above, if the secondary resistance changes with temperature, a large error occurs in the calculation of the slip frequency command ωs *, and the original vector control is performed. Cannot be maintained, and the characteristics deteriorate.

Therefore, the means for detecting or estimating that the secondary resistance has changed due to temperature is detected or estimated by some means, and is reflected in the process of calculating the torque current command iq1 * and the slip frequency command ωs *, so that the vector control characteristic is changed. Need to compensate.

In view of the above problems, it is an object of the present invention to provide an air conditioner that corrects a temperature change of a secondary resistance of a motor and compensates for a decrease in vector control characteristics due to the temperature change in slip frequency type vector control. And

[0036]

In order to achieve the above object, an air conditioner according to the present invention comprises a compressor whose rotation speed is controlled by a power converter, and a current detector for detecting a primary current of the compressor. A speed detector for detecting the number of revolutions of the compressor based on an output signal of the current detector, an output signal of a shell discharge pressure detector for detecting a shell discharge pressure of the compressor, and a shell suction pressure of the compressor. A discharge end temperature / motor temperature estimating circuit for estimating a discharge end temperature and a motor temperature inside the compressor from an output signal of a shell suction pressure detector to perform compression; and A secondary resistance estimating circuit for estimating a secondary resistance of a motor inside the machine, and a vector control command for driving the power converter from an output signal of the speed detector and an output signal of the secondary resistance estimating circuit. The vector control command calculation circuit corrects the temperature change of the secondary resistance of the motor, which is the calculation element of the vector control command, by the output signal of the secondary resistance estimation circuit. It compensates for the degradation of the vector control characteristics.

A discharge end inside the compressor is obtained from an output signal of a shell discharge temperature detector for detecting a shell discharge temperature of the compressor and an output signal of a shell suction pressure detector for detecting a shell suction pressure of the compressor. A discharge end temperature / motor temperature estimation circuit for estimating a temperature and a motor temperature, and a secondary resistance estimation circuit for estimating a secondary resistance of a motor inside the compressor from an output signal of the discharge end temperature / motor temperature estimation circuit, A vector control command calculation circuit for driving the power converter from the output signal of the speed detector and the output signal of the secondary resistance estimation circuit, wherein the vector control command calculation circuit is The output signal of the estimating circuit corrects the temperature change of the secondary resistance of the motor, which is the operation element of the vector control command, and compensates for the deterioration of the vector control characteristic due to the temperature change It is.

Further, a discharge end inside the compressor is obtained from an output signal of a shell discharge pressure detector for detecting a shell discharge pressure of the compressor and an output signal of a shell suction pressure detector for detecting a shell suction pressure of the compressor. A discharge end temperature / motor temperature estimating circuit for estimating a temperature and estimating a motor temperature inside the compressor from an output signal of the shell discharge temperature detector for detecting the discharge end temperature and a shell discharge temperature of the compressor, A secondary resistance estimating circuit for estimating a secondary resistance of the motor inside the compressor from an output signal of the discharge end temperature / motor temperature estimating circuit; an output signal of the speed detector; and an output of the secondary resistance estimating circuit. And a vector control command calculation circuit for driving the power converter from the signals. It corrects the temperature variation of the secondary resistance of the motor is an operation element of the vector control command, characterized in that to compensate for the reduction of the vector control characteristics due to a temperature change.

[0039]

According to the present invention, the above-described configuration compensates for the secondary resistance R2 * that changes with temperature to prevent a decrease in control accuracy due to a change in the secondary resistance, thereby realizing an efficient air conditioner.

[0040]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An air conditioner according to an embodiment of the present invention will be described below with reference to the drawings. Components having the same configuration as the conventional example are denoted by the same reference numerals, and description thereof is omitted.

FIG. 1, FIG. 2, FIG. 3, FIG. 4, FIG.
1 shows a first embodiment of the present invention. In FIG. 1, reference numeral 5a denotes an accumulator for feeding the gas discharged from the compressor 1 in a completely gaseous state. Reference numeral 37 denotes a shell discharge pressure detector for detecting the shell discharge pressure of the compressor 1, and 44 denotes a shell suction pressure detector for detecting the pressure in the shell suction pipe of the compressor 1, and the shell discharge pressure detector 37 and the shell discharge pressure detector. The suction pressure detector 44 is connected to the shell discharge temperature / motor temperature estimation circuit 43 shown in FIG. 4, and the shell discharge temperature / motor temperature estimation circuit 43 is connected to the secondary resistance estimation circuit 34.

The slip frequency command ωs * is calculated by (Equation 2). Therefore, if R2 * changes with temperature, the torque current command iq1 * and the slip frequency command ωs * include an error. As a result, the primary frequency ω1 also includes an error, and the phase angle θ1 * of the primary current also includes an error. Therefore, the orthogonal relationship between the exciting current and the torque current cannot be maintained, and the vector control characteristics deteriorate.

In this embodiment, a shell discharge pressure detector 37 for detecting the shell discharge pressure of the compressor 1 and a char suction pressure detector 44 for detecting the suction temperature of the suction pipe of the compressor 1 are provided.
A discharge end temperature / motor temperature estimation circuit A43 for estimating the discharge end temperature and the motor temperature inside the compressor 1 and a secondary resistance estimation circuit 34 for estimating the secondary resistance of the motor inside the compressor 1 from the motor temperature are added. The result is to be reflected in the calculation of the torque current and the calculation of the slip frequency.

Hereinafter, the flow of the method of correcting the secondary resistance will be described.
This will be described with reference to FIGS. 3, 4, 5, and 6.

FIG. 3 is a Mollier diagram, in which the vertical axis represents pressure and the horizontal axis represents enthalpy. In FIG. 1, the degree of superheat is 0 ° C. due to the presence of the accumulator 5a, and the Mollier diagram shown in FIG. 3 is obtained. From the Mollier diagram of FIG.
If the shell discharge pressure P2 and the shell suction pressure G are known,
It can be seen that the discharge end temperature T2 can be estimated, and the motor temperature Mo can be estimated therefrom.

The shell discharge pressure P 2 of the compressor 1 detected by the shell discharge pressure detector 37 and the shell suction pressure detector 44
The shell suction pressure G <b> 1 detected at (1) is input to the discharge end temperature / motor temperature estimation circuit 43.

In the discharge end temperature / motor temperature estimating circuit 43, the shell discharge pressure and discharge end set for each of the shell suction pressures G0, G1, and G2 of the compressor 1 set in the design stage as shown in FIG. The discharge end temperature T2 is estimated from the characteristic indicating the temperature relationship, and the discharge end temperature set for each of the suction pressures G0, G1, and G2 of the compressor 1 set at the design stage shown in FIG. The motor temperature Mo is estimated from a characteristic indicating the relationship between the motor temperatures. This result is input to the secondary resistance estimation circuit 34.

The secondary resistance estimating circuit 34 calculates the secondary resistance R2 * from the characteristic indicating the relationship between the secondary resistance and the motor temperature set at the design stage as shown in FIG. The torque current calculator 27 and the slip frequency calculator 35 correct the temperature of the secondary resistance with respect to the temperature.

As described above, according to the present embodiment, the sensors required for correcting the secondary resistance need only be of two types that detect the shell discharge pressure of the compressor 1 and the shell suction pressure of the suction pipe. Both types are easy to install, and the secondary resistance is corrected using the correlation between the shell suction pressure, the shell discharge pressure, and the discharge end temperature and the correlation between the motor temperature inside the compressor 1 and the motor secondary resistance. The calculation of the torque current command and the slip frequency command can be performed more accurately than in the conventional case where the calculation is performed with the secondary resistance R2 * being a constant value.

Next, a second embodiment of the present invention will be described with reference to FIGS. 7, 8, 9 and 10.

In FIG. 7, reference numeral 33 denotes a shell discharge pressure detector for detecting the discharge pressure of the compressor 1, and reference numeral 44 denotes a shell suction pressure detector for detecting the suction pressure of the compressor 1. The shell suction pressure detector 44 and the shell discharge temperature detector 33 are connected to the discharge end temperature / motor temperature estimation circuit B46 in FIG. It is connected to the.

In this embodiment, a shell suction pressure detector 44 for detecting the suction pressure of the compressor 1, a shell discharge temperature detector 33 for detecting the discharge temperature, and a discharge end temperature and a motor temperature inside the compressor 1 are estimated. In addition, a discharge end temperature / motor temperature estimating circuit 46 and a secondary resistance estimating circuit 34 for estimating the secondary resistance from the motor temperature are added, and the results are reflected in the torque current calculation and the slip frequency calculation.

Hereinafter, the flow of the method of correcting the secondary resistance will be described.
This will be described with reference to FIGS. FIG. 9 is a Mollier diagram, in which the vertical axis is pressure and the horizontal axis is enthalpy. Compressor 1
It can be understood that in order to accurately detect the motor temperature inside the compressor 1 with respect to the load fluctuation, the motor temperature Mo can be estimated if two points of the shell discharge temperature T1 and the discharge end temperature T2 of the compressor 1 can be detected.

Therefore, the suction pressure P1 of the compressor 1 detected by the shell suction pressure detector 44 and the shell discharge temperature detector 33
The shell discharge temperature T1 of the compressor 1 detected in the step (1) is input to the discharge end temperature / motor temperature estimation circuit 46, and the discharge end temperature / motor temperature estimation circuit 46 reduces the degree of superheat in the Mollier diagram of FIG. Since the adiabatic compression is ideally performed at 0 ° C., the discharge end temperature T2 is estimated, and an estimated value Mo of the motor temperature is obtained by (Equation 3).
The obtained estimated value Mo of the motor temperature is used as the secondary resistance estimation circuit 3.
4 is input.

[0055]

(Equation 3)

In equation (3), Mo is the motor temperature, T
2 is the discharge end temperature, and ΔT is a correction coefficient set at the design stage.

The secondary resistance estimating circuit 34 calculates the secondary resistance R2 * from the characteristic indicating the relationship between the secondary resistance and the motor temperature set at the design stage as shown in FIG. 27 and the slip frequency calculator 35, and the torque current calculator 27 and the slip frequency calculator 35 correct the temperature of the secondary resistance.

As described above, according to the present embodiment, two types of sensors, one for detecting the suction pressure of the compressor 1 and the other for detecting the discharge temperature, are used to correct the secondary resistance. By estimating the temperature, the correction of the secondary resistance can be accurately detected with respect to the load fluctuation. Can be calculated more accurately.

Next, a third embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIGS. 1, 12, 13, and 14.

In FIG. 11, reference numeral 44 denotes a shell suction pressure detector for detecting the suction pressure of the compressor 1, 33 a shell discharge temperature detector for detecting the discharge temperature, and 37 a shell discharge pressure detector for detecting the discharge pressure. It is.

The shell suction pressure detector 44, the shell discharge temperature detector 33, and the shell discharge pressure detector 37 are connected to a discharge end temperature / motor temperature estimation circuit 49 shown in FIG. The temperature estimating circuit 49 is connected to the secondary resistance estimating circuit 34.

In this embodiment, a shell suction pressure detector 44 for detecting the suction pressure of the compressor 1, a shell discharge temperature detector 33 for detecting the discharge temperature, a shell discharge pressure detector 37 for detecting the discharge pressure, Discharge end temperature / motor temperature estimation circuit 49 for estimating the discharge end temperature and the motor temperature inside the compressor 1
And a secondary resistance estimating circuit 34 for estimating the secondary resistance of the motor inside the compressor 1 from the motor temperature is added, and the result is reflected in the torque current calculation and the slip frequency calculation.

Hereinafter, the flow of the method of correcting the secondary resistance will be described.
This will be described with reference to FIGS. FIG. 13 is a Mollier diagram, in which the vertical axis is pressure and the horizontal axis is enthalpy. In order to accurately detect the temperature of the motor inside the compressor 1 with respect to the load variation, the shell discharge temperature T1 and the discharge end temperature inside the compressor 1 with respect to the discharge pressure P2 of the compressor 1 are used. By detecting two points at a certain T2, the motor temperature M
It can be seen that o can be accurately estimated.

Therefore, the shell suction pressure P1 and the shell discharge temperature T of the compressor 1 detected by the shell suction pressure detector 44, the shell discharge temperature detector 33, and the shell discharge pressure detector 37 are detected.
2 and the shell discharge pressure P2 are input to a discharge end temperature / motor temperature estimation circuit C49. In the discharge end temperature / motor temperature estimating circuit C49, the superheat degree in the Mollier diagram of FIG. 3 is 0 ° C. and the adiabatic compression is ideally performed by the effect of the accumulator 5a from the shell suction pressure P1 and the shell discharge pressure P2. Therefore, in addition to estimating the discharge end temperature T2, the calculation shown in (Equation 4) is performed to estimate the motor temperature.

[0065]

(Equation 4)

In equation (4), T1 is the shell discharge temperature, T2 is the discharge end temperature K inside the compressor 1, and is a constant set at the design stage.

Then, the discharge end temperature / motor temperature estimation circuit 4
9, the motor temperature Mo is output from the secondary resistance estimating circuit 3.
4 is input.

The secondary resistance estimating circuit 34 calculates the secondary resistance R2 * from the characteristic set at the design stage and shows the relationship between the secondary resistance and the motor temperature as shown in FIG. Input to the slip frequency calculator 35,
The torque current calculator 27 and the slip frequency calculator 35 correct the temperature of the secondary resistance.

As described above, according to the present embodiment, three types of sensors for detecting the suction pressure of the compressor 1, detecting the discharge temperature, and detecting the discharge pressure are required for correcting the secondary resistance. In addition to being able to accurately detect the correction of the secondary resistance with respect to load fluctuations and reacting sensitively and accurately to fine system load fluctuations, the temperature of the motor inside the compressor 1 is determined by the shell discharge temperature. Since the estimated temperature range can be narrowed by estimating from the discharge end temperature inside the compressor 1 obtained from the shell discharge pressure, the estimated value of the secondary resistance itself becomes more accurate, and the calculation of the torque current command and the slip frequency command is performed. It can be performed with high accuracy.

The shell suction temperature, shell suction pressure, shell discharge temperature, and shell discharge pressure in the first, second, and third embodiments are used for system control of the air conditioner.
The present invention can also be used for the secondary resistance correction control of the present invention, and can be easily realized.

[0071]

As described above, the present invention provides a compressor whose rotation speed is controlled by a power converter, a current detector for detecting a primary current of the compressor, and a current detection for detecting the rotation speed of the compressor. From the output signal of the speed detector, which is detected by the output signal of the compressor, the output signal of the shell discharge pressure detector, which detects the shell discharge pressure of the compressor, and the output signal of the shell suction pressure detector, which detects the shell suction pressure of the compressor. A discharge end temperature / motor temperature estimation circuit for estimating a discharge end temperature and a motor temperature inside the compressor, and a secondary resistance of a motor inside the compressor is estimated from an output signal of the discharge end temperature / motor temperature estimation circuit. A secondary resistance estimating circuit, by including a vector control command operation circuit that drives the power converter from the output signal of the speed detector and the output signal of the secondary resistance estimating circuit,
The sensors required to correct the secondary resistance are only two types that detect the discharge pressure of the compressor and the shell suction pressure of the suction pipe, and both types are easy to install, and the shell suction pressure and the shell discharge pressure The secondary resistance is corrected by using the correlation between the motor and the shell discharge temperature and the correlation between the motor temperature inside the compressor and the motor secondary resistance. It can be performed accurately, unlike the conventional case where the calculation is performed as

The output signal of the shell discharge temperature detector for detecting the shell discharge temperature of the compressor and the output signal of the shell suction pressure detector for detecting the shell suction pressure of the compressor are obtained from the discharge end inside the compressor. A discharge end temperature / motor temperature estimation circuit for estimating a temperature and a motor temperature, and a secondary resistance estimation circuit for estimating a secondary resistance of a motor inside the compressor from an output signal of the discharge end temperature / motor temperature estimation circuit, By providing a vector control command operation circuit that drives the power converter from the output signal of the speed detector and the output signal of the secondary resistance estimating circuit, correction of the secondary resistance can reduce the shell discharge temperature of the compressor 1. Two types of sensors, detection and shell suction pressure detection, are required.However, by estimating the motor temperature from the discharge end temperature inside the compressor, the secondary resistance correction can be accurately detected with respect to load fluctuations. Can therefore sensitively system may react to load fluctuations in the detailed system than conventional, the calculation of the torque current command and the slip frequency command can be performed more accurately to the fine load fluctuation.

Further, a discharge end inside the compressor is obtained from an output signal of a shell discharge pressure detector for detecting a shell discharge pressure of the compressor and an output signal of a shell suction pressure detector for detecting a shell suction pressure of the compressor. A discharge end temperature / motor temperature estimating circuit for estimating a temperature and estimating a motor temperature inside the compressor from an output signal of the shell discharge temperature detector for detecting the discharge end temperature and a shell discharge temperature of the compressor, A secondary resistance estimating circuit for estimating a secondary resistance of the motor inside the compressor from an output signal of the discharge end temperature / motor temperature estimating circuit; an output signal of the speed detector; and an output of the secondary resistance estimating circuit. And a vector control command calculation circuit for driving the power converter from the signals, the detection of the shell suction pressure of the compressor, the detection of the shell discharge temperature and the shell Three types of sensors are required to detect the output pressure, but in addition to being able to accurately detect the secondary resistance correction for load fluctuations, and responding sensitively and precisely to fine system load fluctuations, By estimating the motor temperature inside the compressor from the shell discharge temperature and the discharge end temperature inside the compressor, the estimated temperature range can be narrowed, so that the estimated value of the secondary resistance itself can be more accurately estimated, and the torque current command And the calculation of the slip frequency command can be performed with high accuracy.

With these configurations, the secondary resistance that changes with temperature is compensated to prevent the control accuracy from being reduced due to the change in the secondary resistance, and an efficient air conditioner can be realized. There is a great thing.

Since the suction pressure, discharge temperature and discharge pressure of the compressor are used for system control of the air conditioner,
The present invention can also be used for the secondary resistance compensation control of the present invention, and can be easily realized.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of an air conditioner according to a first embodiment of the present invention.

FIG. 2 is a block diagram of an inverter control device of the air conditioner according to the first embodiment of the present invention.

FIG. 3 is a Mollier diagram of the air conditioner according to the first embodiment of the present invention.

FIG. 4 shows the shell discharge temperature and temperature in the first embodiment of the present invention.
Characteristic diagram showing the relationship between shell discharge pressure, shell discharge temperature, and refrigerant flow rate set in the motor temperature estimation circuit

FIG. 5 shows the shell discharge temperature and temperature in the first embodiment of the present invention.
Characteristic diagram showing the relationship between the shell discharge temperature set in the motor temperature estimation circuit, the motor temperature, and the refrigerant flow rate

FIG. 6 is a characteristic diagram showing a relationship between a motor temperature and a secondary resistance set in a secondary resistance estimation circuit.

FIG. 7 is a schematic configuration diagram of an air conditioner according to a second embodiment of the present invention.

FIG. 8 is a block diagram of an inverter control device of an air conditioner according to a second embodiment of the present invention.

FIG. 9 is a Mollier diagram of an air conditioner according to a second embodiment of the present invention.

FIG. 10 is a characteristic diagram showing a relationship between a motor temperature and a secondary resistance set in a secondary resistance estimation circuit.

FIG. 11 is a schematic configuration diagram of an air conditioner according to a third embodiment of the present invention.

FIG. 12 is a block diagram of an inverter control device of an air conditioner according to a third embodiment of the present invention.

FIG. 13 is a Mollier diagram of an air conditioner according to a third embodiment of the present invention.

FIG. 14 is a characteristic diagram showing a relationship between a motor temperature and a secondary resistance set in a secondary resistance estimation circuit.

FIG. 15 is a schematic configuration diagram of an air conditioner in a conventional example.

FIG. 16 is a block diagram of a slip frequency type vector control inverter device of an air conditioner in a conventional example.

FIG. 17 is a block diagram of a torque current calculator of a conventional slip frequency type vector control inverter device of an air conditioner.

FIG. 18 is a block diagram of a slip frequency calculator of a slip frequency type vector control inverter device of an air conditioner in a conventional example.

FIG. 19 is a block diagram of a magnetic flux detection type vector control inverter device of a conventional air conditioner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 27 Torque current calculator 33 Shell discharge temperature detector 35 Slip frequency calculator 34 Secondary resistance estimation circuit 37 Shell discharge pressure detector 43 Shell discharge temperature / motor temperature estimation circuit 44 Shell suction pressure detector 46 Discharge end temperature・ Motor temperature estimation circuit 49 Discharge end temperature ・ Motor temperature estimation circuit

Claims (3)

(57) [Claims] 1. A compressor whose rotation speed is controlled by a power converter, a current detector for detecting a primary current of the compressor,
A speed detector for detecting the number of revolutions of the compressor based on an output signal of the current detector, an output signal of a shell discharge pressure detector for detecting a shell discharge pressure of the compressor, and a shell suction pressure of the compressor. A discharge end temperature / motor temperature estimating circuit for estimating a discharge end temperature and a motor temperature inside the compressor from an output signal of the shell suction pressure detector; and A secondary resistance estimating circuit for estimating a secondary resistance of an internal motor, and a vector control command operation circuit for driving the power converter from an output signal of the speed detector and an output signal of the secondary resistance estimating circuit. The vector control command calculation circuit detects the temperature change of the secondary resistance of the motor, which is the calculation element of the vector control command, based on the output signal of the secondary resistance estimation circuit. Correct, air conditioner, characterized in that to compensate for the reduction of the vector control characteristics due to a temperature change. 2. A compressor whose rotation speed is controlled by a power converter, a current detector for detecting a primary current of the compressor,
A speed detector that detects the number of revolutions of the compressor based on an output signal of the current detector, an output signal of a shell discharge temperature detector that detects a shell discharge temperature of the compressor, and a shell suction pressure of the compressor. A discharge end temperature / motor temperature estimating circuit for estimating a discharge end temperature and a motor temperature inside the compressor from an output signal of a shell suction pressure detector, and the compressor based on an output signal of the discharge end temperature / motor temperature estimating circuit. A secondary resistance estimating circuit for estimating a secondary resistance of an internal motor, and a vector control command operation circuit for driving the power converter from an output signal of the speed detector and an output signal of the secondary resistance estimating circuit. The vector control command calculation circuit detects the temperature change of the secondary resistance of the motor, which is the calculation element of the vector control command, based on the output signal of the secondary resistance estimation circuit. Correct, air conditioner, characterized in that to compensate for the reduction of the vector control characteristics due to a temperature change. 3. A compressor whose rotation speed is controlled by a power converter, a current detector for detecting a primary current of the compressor,
A speed detector that detects the number of revolutions of the compressor based on an output signal of the current detector; an output signal of a shell discharge pressure detector that detects a shell discharge pressure of the compressor; and a shell suction pressure of the compressor. The compressor detects a discharge end temperature inside the compressor from an output signal of a shell suction pressure detector to be detected, and detects the discharge end temperature and an output signal of a shell discharge temperature detector for detecting a shell discharge temperature of the compressor. A discharge end temperature / motor temperature estimation circuit for estimating an internal motor temperature, and a secondary resistance estimation circuit for estimating a secondary resistance of a motor inside the compressor from an output signal of the discharge end temperature / motor temperature estimation circuit, An output signal of the speed detector and an output signal of the secondary resistance estimating circuit, a vector control command operation circuit that drives the power converter, and the vector The control command calculation circuit corrects a temperature change of the secondary resistance of the motor, which is a calculation element of the vector control command, by an output signal of the secondary resistance estimation circuit, and compensates for a decrease in vector control characteristics due to the temperature change. Air conditioner.