JP2006115575A - Inverter device, compressor drive device and refrigeration / air-conditioning device - Google Patents

Abstract

An inverter device that enables stable operation of a synchronous motor or the like with simple control is realized.
In a microcomputer 7 that controls an inverter circuit 2 that converts DC power into AC power, a phase difference between an AC voltage and an AC current is detected, and the detected AC voltage / current phase difference information and a target are detected. A duty reference value corresponding to an error from the phase difference information is calculated. Further, the vibration component of the phase difference between the AC voltage and the AC current is detected, and the correction amount of the rotational speed of the synchronous motor 1 is calculated based on this vibration component. Based on the calculated duty reference value and sine wave data corresponding to the corrected rotation speed command value, a PWM waveform signal is generated and output to the inverter circuit 2.
[Selection] Figure 1

Description

  The present invention relates to an inverter device for driving a motor. Further, the present invention relates to a compressor driving device driven by the inverter device, a refrigeration device equipped with the inverter device, and an air conditioner (collectively referred to as refrigeration Air conditioner).

  Permanent magnet synchronous motors are widely used because they have excellent maintainability, controllability, and environmental resistance, and can be operated with high efficiency and high output. Synchronous reluctance motors that do not use permanent magnets are also actively studied as inexpensive and easy-to-recycle motors.

  In order to perform high-performance control of a synchronous motor such as a permanent magnet synchronous motor or a synchronous reluctance motor, it is important to flow a sine wave current according to the position of the rotor. Therefore, in general, a position sensor that detects the position of a rotor such as a Hall element, an encoder, or a resolver is used in the motor control device. Further, in place of the position sensor, Patent Literature 1 and Patent Literature 2 disclose a method for indirectly obtaining the rotor position by calculation based on information on the voltage and current of the motor.

  However, in the case of a position sensor, not only is it a major factor that hinders downsizing of the equipment, but it also requires multiple wires and receiving circuits to transmit the position sensor signal, so reliability, workability, cost, etc. There was a problem. In addition, in the method of indirectly calculating the position of the rotor based on information on the voltage and current of the motor, there is a problem that the control device becomes expensive because complicated and high-speed calculation processing is required.

  In view of the above problems, a control is disclosed that is controlled by the phase difference between the voltage and current of the synchronous motor. Here, the synchronous motor drive device controlled by the phase difference between the voltage and current of the synchronous motor will be described. FIG. 7 is a control block diagram of a conventional synchronous motor driving apparatus.

  As shown in FIG. 7, the synchronous motor driving device includes an AC power supply 4 for supplying electric power, AC power and DC power to drive a synchronous motor 1 having a three-phase coil in a stator and a permanent magnet in a rotor. An inverter circuit 2 and a converter circuit 3 that convert the motor current, a current sensor 5 that detects a motor current, a motor current detection amplifier unit 6 that amplifies the detected motor current and adds an offset, and a microcomputer 7 that controls them It is composed of

  According to the above configuration, the power supplied from the AC power source 4 is converted into AC power via the inverter circuit 2 and the converter circuit 3, and the converted AC power is supplied to the synchronous motor 1 to drive the motor.

  The current sensor 5 detects a motor current flowing in a specific phase (hereinafter referred to as a U phase) among the phases of the coil terminals U, V, and W of the synchronous motor 1. The motor current detected by the current sensor 5 is given to the motor current detection amplifier unit 6, and a predetermined amount of amplification and offset are added, and a motor current signal is given to the control unit 7.

  The microcomputer 7 includes a phase difference detection unit 8, a target phase difference information storage unit 9, an adder 10, a PI calculation unit 11, a rotation speed setting unit 12, a sine wave data table 13, and sine wave data creation. Unit 14 and PWM creation unit 15, and each process is performed in software according to each program.

  The phase difference detection unit 8 takes in a motor current signal supplied from the motor current detection amplifier unit 6 by A / D conversion at a predetermined timing, and samples the drive voltage phases of the two synchronous motors 1 for each period. The motor sampling area is calculated by integrating the current sampling data. The calculated area ratio between the two motor current signal areas is output as phase difference information.

  The target phase difference information storage unit 9 stores target phase difference information. Error data between the target phase difference information and the phase difference information is calculated by the adder 10. The PI calculation unit 11 calculates proportional error data and integral error data with respect to the calculated error data, and outputs a duty reference value. The addition unit 10 and the PI calculation unit 11 constitute a phase difference control unit 27.

  The rotation speed setting unit 12 sets a rotation speed command for the synchronous motor 1. The sine wave data table 13 stores sine wave data corresponding to a predetermined rotational speed of the synchronous motor. The sine wave data creation unit 14 reads out sine wave data corresponding to each phase of the coil terminals U, V, and W of the synchronous motor from the sine wave data table 13 according to the rotational speed command of the synchronous motor 1 and the passage of time. U-phase motor drive voltage phase information is output based on the U-phase sine wave data. The PWM creation unit 15 creates a PWM waveform based on the sine wave data and the duty reference value, and outputs the created PWM waveform to the drive elements of the synchronous motor terminals U, V, and W of the inverter circuit 2.

Patent Document 3 discloses a method for realizing sinusoidal driving by controlling the phase difference between the motor voltage and the motor current, such as the above-described synchronous motor driving device. Patent Document 4 discloses a method for improving the stability of synchronous motor driving by preventing torque and current vibrations and step-out at the time of sudden load change in a synchronous motor driving apparatus using V / f constant control.
Japanese Unexamined Patent Publication No. 07-177799 (paragraphs 0005 to 0007, FIG. 1) JP 07-245981 A (paragraphs 0005 to 0013, FIG. 1) JP 2001-112287 A (paragraph 0021 to paragraph 0042, FIG. 1) JP 2000-236694 A (paragraphs 0007 to 0013, FIG. 1)

  In Patent Document 3, the control device can be made inexpensive because the control of the synchronous motor is simple. However, when a large fluctuation occurs in the load, turbulence occurs. When the amplitude of this turbulence is large, there is a problem in stability such that recovery is impossible and operation is impossible due to step-out.

  Patent Document 4 is more stable than Patent Document 3, but requires a current sensor that detects a two-phase current, and there are problems in cost reduction and miniaturization. In addition, calculation processing such as coordinate conversion from the three-phase coordinate system to the two-phase coordinate system is required, so that the calculation amount of the microcomputer increases and the calculation takes too much time. For example, as the synchronous motor is driven at a higher speed, the time required for the calculation becomes longer, and there is a problem that the calculation is not completed within a predetermined time corresponding to the number of rotations and the driving becomes impossible.

  Therefore, an object of the present invention is to provide an inexpensive and high-performance inverter device that enables stable synchronous motor operation with a simple configuration and control.

  In order to achieve the object, the present invention includes an inverter circuit that converts DC power into AC power, and a control device that controls the inverter circuit by a phase difference control method, and the control device flows through the inverter circuit. The current reference means for detecting current, the phase difference detection means for detecting the phase difference between the AC voltage and the AC current, and the duty reference value is adjusted according to the error between the detected phase difference and the target phase difference Adjusting means for detecting, phase difference vibration detecting means for detecting the detected vibration component of the phase difference, frequency correction amount calculating means for calculating a frequency correction amount based on the vibration component of the phase difference, and the calculated Frequency correction means for correcting the frequency command value based on the frequency correction amount, output waveform data corresponding to the corrected frequency command value, and the adjusted duty reference value Zui has a PWM signal generating means for calculating a PWM signal, the controller, and outputs the PWM signal to the inverter circuit.

  The current detection means is provided with a current detection resistor in a DC circuit connecting the inverter circuit and the converter circuit, and detects a DC current flowing through the inverter circuit based on a voltage generated at both ends of the current detection resistor. The phase difference detection means detects the phase difference between the AC voltage and the AC current based on the detected DC current, and uses this as AC voltage / current phase difference information. The adjustment unit compares the detected AC voltage / current phase difference information with the target phase difference information, and calculates a duty reference value corresponding to the error.

  Further, as the current detection means for detecting the current, an alternating current polarity detection means for detecting the polarity of the alternating current flowing through the inverter circuit may be used. In this case, the phase difference detection means detects the phase difference between the AC voltage and the AC current when the AC current polarity is reversed.

  The phase difference vibration detection unit detects a vibration component of the phase difference from the AC voltage / current phase difference information detected by the phase difference detection unit, and corrects the frequency based on the detected vibration component.

  Further, the frequency correction amount calculation means adjusts the magnitude of the frequency correction amount according to the magnitude of the phase difference vibration component. For example, when the vibration component detected by the phase difference vibration detection means is large, the frequency correction amount is increased. When the vibration component is small, the frequency correction amount is reduced. The adjustment of the frequency correction amount is not only detected from the alternating current oscillation component, but may be performed according to the magnitude of the alternating voltage frequency or the duty reference value, for example.

  Moreover, it is good also as a motor drive inverter apparatus by providing a synchronous motor in the output side of an inverter circuit. In this case, since the rotational speed of the motor and the frequency are in a proportional relationship, the control device includes a current detection unit that detects a current flowing through the inverter circuit, and a phase difference detection unit that detects a phase difference between the AC voltage and the AC current. And an adjustment means for adjusting a duty reference value according to an error between the detected phase difference and a target phase difference, and removing the DC component of the phase difference detected by the phase difference detection means. Phase difference vibration detection means for detecting a vibration component of phase difference, rotation speed correction amount calculation means for calculating a rotation speed correction amount of the motor based on the vibration component of phase difference, and the calculated rotation speed correction amount Based on the motor rotation speed correction means for correcting the motor rotation speed command value based on the output waveform data corresponding to the corrected motor rotation speed command value and the adjusted duty reference value. Has a PWM signal generating means for calculating, said control device outputs the PWM signal to the inverter circuit.

  The current detection means is provided with a current detection resistor in a DC circuit connecting the inverter circuit and the converter circuit, and detects a DC current flowing through the inverter circuit based on a voltage generated at both ends of the current detection resistor, or Alternatively, AC current polarity detection means for detecting the polarity of the AC current flowing through the inverter circuit may be used. In the case of alternating current polarity detection means, the phase difference detection means detects the phase difference between the alternating voltage and the alternating current at the time when the alternating current polarity is reversed.

  According to the present invention, 180-degree energization driving including sinusoidal driving can be performed without providing a rotor position sensor or motor current sensor, and motor efficiency can be improved, and noise and vibration can be realized. Further, the amount of calculation of the microcomputer is reduced, and the processing speed of the A / D converter, the microcomputer, etc. can be lowered. Therefore, it is possible to obtain a highly reliable inverter device that can control motor torque and current vibration with a simple configuration and control, prevent step-out and perform stable control, and is small and highly reliable. A compressor driving device and a refrigeration / air conditioning device can be provided.

[First Embodiment]
Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 is a block diagram showing a schematic configuration of an inverter device according to a first embodiment of the present invention, FIG. 2 is a waveform diagram of U-phase voltage / current and phase difference / phase difference oscillation components of the inverter circuit, and FIG. 3 is current oscillation. FIG. 4 is a block diagram illustrating a schematic configuration of the rotation speed correction amount calculation unit, and FIG. 5 is a block diagram illustrating a schematic configuration of the rotation speed correction amount calculation unit. It is.

  In the inverter apparatus for driving a motor according to the present invention, as shown in FIG. 1, a motor 1 which is a three-phase synchronous motor is connected to the output side of an inverter circuit 2, and is driven by inverter control. The inverter circuit 2 is supplied with the AC voltage from the AC power source 4 converted into a DC voltage by the converter circuit 3.

  A current detection resistor 21 is provided on the negative side of the DC circuit connecting the converter circuit 3 and the inverter circuit 2. Based on the voltage generated at both ends of the current detection resistor 21, the DC current detection amplifier unit 22 detects the DC current flowing through the inverter circuit 2. The direct current detection amplifier unit 22 is connected to the microcomputer 7 as a control device, amplifies the detected direct current, and outputs it to the microcomputer 7 as a direct current signal. The DC current detection amplifier unit 6 serves as DC current detection means for detecting a DC current flowing through the inverter circuit 2.

  The microcomputer 7 includes a phase difference detection unit 8, a target phase difference information storage unit 9, an adder 10, a PI calculation unit 11, a rotation speed setting unit 12, a sine wave data table 13, a sine wave data creation unit 14, and a PWM creation unit. 15, a motor current estimation unit 16, a phase difference vibration detection unit 17, a rotation speed correction amount calculation unit 18, and a rotation speed correction unit 19, and each process is performed in software according to a program.

  The motor current estimation unit 16 obtains a change in the DC current from the input DC current signal by the current change calculation means, and estimates and calculates the motor current signal by the distribution calculation means for the change in the DC current signal. Here, the current change calculation means and the distribution calculation means are described in Japanese Patent Application Laid-Open No. 8-19263.

  The phase difference detecting unit 8 detects motor voltage / current phase difference information (see FIG. 2C) using the motor current signal estimated by the motor current estimating unit 16 (see FIG. 2B).

  The target phase difference information storage unit 9 stores target phase difference information, and the adder 10 calculates error data between the target phase difference information and the phase difference information output from the phase difference detection unit 8, The calculation result is output to the PI calculation unit 11. The PI calculation unit 11 calculates proportional error data (P) and integration error data (I) with respect to the calculated error data, and outputs a duty reference value to the PWM generation unit 15.

  The phase difference vibration detection unit 17 detects the vibration component of the motor voltage / current phase difference information based on the motor voltage / current phase difference information detected by the phase difference detection unit 8. The rotation speed correction amount calculation unit 18 calculates the rotation speed correction amount based on the vibration component detected by the current vibration detection unit 17. The rotation speed setting unit 12 stores a target rotation speed command value, and the rotation speed correction unit 19 stores error data between the rotation speed command value and the rotation speed correction amount output from the rotation speed correction amount calculation unit 18. And the calculation result is output to the sine wave data creation unit 14.

  The sine wave data table 13 stores in advance sine wave data composed of a predetermined number of data, and outputs the sine wave data to the sine wave data creation unit 14. The sine wave data creation unit 14 reads out sine wave data corresponding to each phase of the motor winding terminals U, V, and W from the error data that is the calculation result of the rotation speed correction unit 19 and the sine wave data table 13. , And outputs the U-phase motor drive voltage phase information to the phase difference detector 8 from the U-phase sine wave data.

  The PWM generator 15 outputs a PWM waveform signal, which is a motor drive voltage, to each drive element of the inverter circuit 2 for each phase from the sine wave data and the duty reference value. Note that the sine wave data may be created by calculation instead of being created based on the sine wave data table 13.

  The adder 10 obtains an error amount between the motor voltage / current phase difference information detected by the phase difference detection unit 8 and the target phase difference information, and the PI calculation unit 11 performs a predetermined amplification on the error amount by P control. To calculate the proportional error amount, integrate the error amount by I control, amplify the value to calculate the integral error amount, and add both to calculate the duty reference value. The PWM generator 15 calculates the output duty each time based on this duty reference value and sine wave data separately obtained from the rotational speed command value, and applies it to the motor winding via the inverter 2 to allow the motor 1 to Driven.

  That is, the magnitude of the drive voltage (duty width of the PWM duty) is determined by the phase difference control feedback loop for controlling the motor winding current phase difference with respect to the motor drive voltage (output duty) to be constant. Further, in order to rotate the motor 1 at a desired rotational speed, the rotational speed is determined by sine wave data output at a desired frequency. As a result, the motor 1 can be driven and controlled with a desired phase difference and a desired rotational speed.

  Next, setting of the rotation speed and PWM output will be described. The phase difference control method according to the present invention is different from the method in which a speed control is performed by detecting a counter electromotive voltage pulse or the like. That is, the rotation speed of the motor 1 is so-called forced excitation drive that is determined by the frequency of a sine wave voltage composed of a PWM wave that is energized to the motor winding.

  Since the phase difference vibration detection unit 17 has a direct current component in the motor voltage / current phase difference information detected from the phase difference detection unit 8, it is difficult to understand the vibration amount as it is. Therefore, the phase difference vibration detection unit 17 removes the direct current component from the phase difference of any one of the plurality of phases detected by the phase difference detection unit 8, and extracts the phase difference vibration component.

  For example, when the specific phase is the U phase phase difference, the phase difference vibration detection unit 17 includes the U phase phase difference in the motor voltage / current phase difference information output from the phase difference detection unit 8 (see FIG. 2C). Enter. This input data is designated as U-phase phase difference data A, and Table 1 shows the U-phase phase difference data A expressed in each time.

  As shown in FIG. 3, the phase difference vibration detection unit 17 passes the input U phase phase difference data A through a high-pass filter 23 to remove a direct current component and to obtain a pure fluctuation amount of a U phase phase difference vibration component ( 2D) is extracted. The extracted vibration component is passed through a proportional amplifier 24 provided in the rotational speed correction amount calculation unit 18 to calculate the rotational speed correction amount. Note that the DC component of the phase difference is, for example, a value to be subtracted in order to capture the value of the phase difference when the phase of the AC voltage is 90 degrees as a pure fluctuation amount.

  Thereby, the magnitude of the rotational speed correction amount can be adjusted according to the magnitude of the vibration component. That is, when the vibration component detected by the phase difference vibration detector 17 is large, the rotational speed correction amount is increased. When the vibration component is small, the rotational speed correction amount is reduced.

  Further, as shown in FIG. 4, the rotational speed correction amount calculation unit 18 passes the vibration component detected by the phase difference vibration detection unit 17 through the proportional amplifier 24 and then multiplies the motor rotational speed command value by the multiplier 25. And the rotational speed correction amount may be calculated. Thereby, the magnitude of the rotational speed correction amount can be adjusted according to the magnitude of the vibration component and the rotational speed.

  Further, as shown in FIG. 5, after passing the vibration component through the proportional amplifier 24, the multiplier 25 multiplies the duty reference value calculated by the PI calculation unit 11 in the multiplier 25 to calculate the rotation speed correction amount. Good. Thereby, the magnitude of the rotational speed correction amount can be adjusted according to the magnitude of the vibration component and the magnitude of the duty reference value. These methods shown in FIGS. 4 and 5 can cope with changes in the motor speed and load conditions.

  The rotation speed correction amount calculation unit 18 performs correction to increase or decrease the rotation speed command value based on the rotation speed correction amount. The corrected rotational speed command value is input to the sine wave data creation unit 14, and sine wave data corresponding to the corrected rotational speed command value is read from the sine wave data table 13.

  Here, the sine wave data table 13 stores a data string in which a sine wave waveform is output when analog values are continuously output. The reference address of this data string is updated by a predetermined number every PWM carrier cycle. If this predetermined number is large, the rotation speed is high. That is, the motor rotation speed is determined by the update interval between the PWM carrier frequency and the reference data in the sine wave data table 13 except for the structural one of the motor 1. For example, if the number of winding phases is 3, the data of each phase may be referred to sine wave data shifted by 120 degrees in electrical angle. In each case, sine wave data may be generated by performing sine wave calculation.

  In the PWM generator 15 such as a PWM waveform generator, the obtained sine wave data of each phase is multiplied by the duty reference value calculated by the phase difference control, the duty width of the PWM duty is determined, and the PWM waveform signal is obtained. It is output to each drive element of the inverter circuit 2. For example, the PWM waveform generator generates a triangular wave at a PWM carrier cycle, compares the peak value of the triangular wave with the multiplied value, and outputs a High / Low signal based on the comparison result.

[Second Embodiment]
FIG. 6 is a block diagram showing a schematic configuration of the inverter device of the second embodiment. Note that in the second embodiment, the same elements as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  As shown in FIG. 6, the second embodiment includes a motor current polarity detection unit 26 that detects the polarity of the alternating current flowing through the inverter circuit 2. The motor current polarity detection unit 26 detects the AC current polarity of each phase of the motor winding terminals U, V, and W flowing in the inverter circuit 2, and logically synthesizes them to form an AC current polarity signal, thereby detecting a phase difference. It outputs to the part 8. The phase difference detection unit 8 detects the phase difference between the AC voltage and the AC current when the AC current polarity is inverted based on the AC current polarity signal output from the motor current polarity detection unit 26.

  Thereby, since only the current polarity information can be extracted, the microcomputer 7 having no A / D conversion function can be used, and the cost can be reduced. The second embodiment is the same as the first embodiment except for the phase difference detection means.

  Here, in a compressor used in a refrigeration / air conditioner or the like, the inside is in a high temperature state, and it is difficult to provide a position sensor for detecting the rotor position such as a Hall IC, so the motor 1 is driven without a position sensor. There is a need to. Therefore, the above inverter device is used to drive the motor of the compressor driving device. As a result, a current sensor configured to detect an alternating current such as a current sensor constituted by a coil and a Hall element and a current transformer is not required, and a position sensor is also unnecessary. And the compressor drive device provided with this inverter apparatus is mounted in a refrigerating / air-conditioning apparatus. This makes it possible to operate a refrigeration / air conditioning apparatus such as a refrigerator, a freezer, or an air conditioner.

  In addition, this invention is not limited to the said embodiment, Of course, many corrections and changes can be added to the said embodiment within the scope of the present invention.

  In this embodiment, the U-phase phase difference data detects a phase difference of a specific phase, but is not limited to this, and may be a V-phase or a W-phase.

  Further, in the present embodiment, the inverter device of the present invention is used for driving a motor of a compressor used in a refrigeration / air conditioning device or the like, but is not particularly limited to this. For example, you may use for electric appliances, such as a fluorescent lamp and an induction heating cooking appliance, or electric products, such as a train, an electric vehicle, and an elevator. Thereby, stable driving can be performed.

The block diagram which shows schematic structure of the inverter apparatus of 1st Embodiment which concerns on this invention. Waveform diagram of U-phase voltage / current and phase difference / phase difference oscillation component of inverter circuit A block diagram showing a schematic configuration of a current vibration detection unit and a rotation speed correction amount calculation unit Block diagram showing schematic configuration of rotation speed correction amount calculation unit Block diagram showing schematic configuration of rotation speed correction amount calculation unit The block diagram which shows schematic structure of the inverter apparatus of 2nd Embodiment. Block diagram showing schematic configuration of conventional inverter device

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Synchronous motor 2 Inverter circuit 3 Converter circuit 4 AC power supply 5 Current sensor 6 Motor current detection amplifier part 7 Microcomputer 8 Phase difference detection part 9 Target phase difference information storage part 10 Adder 11 PI calculation part 12 Rotation speed setting part 13 Sine Wave data table 14 Sine wave data creation unit 15 PWM creation unit 16 Motor current estimation unit 17 Phase difference vibration detection unit 18 Speed correction amount calculation unit 19 Speed correction unit 21 Current detection resistor 22 DC current detection amplifier unit 23 High-pass filter 24 Proportional amplifier 25 Multiplier 26 Current polarity detector A U phase difference data

Claims (12)

An inverter circuit that converts DC power into AC power; and a control device that controls the inverter circuit by a phase difference control method, wherein the control device detects current flowing through the inverter circuit; and AC voltage A phase difference detection means for detecting a phase difference between the AC current and the AC current; an adjustment means for adjusting a duty reference value according to an error between the detected phase difference and a target phase difference; and the detected phase difference A phase difference vibration detecting means for detecting a vibration component of the phase, a frequency correction amount calculating means for calculating a frequency correction amount based on the vibration component of the phase difference, and correcting a frequency command value based on the calculated frequency correction amount PW that calculates a PWM signal based on the frequency correction means that performs, the output waveform data corresponding to the corrected frequency command value, and the adjusted duty reference value It has a signal creation unit, wherein the control device, an inverter device and outputs the PWM signal to the inverter circuit. The inverter device according to claim 1, wherein the current detection means detects a direct current flowing through the inverter circuit. An inverter circuit that converts DC power into AC power; and a control device that controls the inverter circuit by a phase difference control method, the control device including current polarity detection means that detects a polarity of a current flowing through the inverter circuit; , A phase difference detecting means for detecting a phase difference between the AC voltage and the AC current when the current polarity is reversed, and a duty reference value is adjusted according to an error between the detected phase difference and a target phase difference Adjusting means for detecting, phase difference vibration detecting means for detecting the detected vibration component of the phase difference, frequency correction amount calculating means for calculating a frequency correction amount based on the vibration component of the phase difference, and the calculated Frequency correction means for correcting the frequency command value based on the frequency correction amount, output waveform data corresponding to the corrected frequency command value, and the adjusted duty reference DOO has a PWM signal generating means for calculating a PWM signal based on said control device, an inverter device and outputs the PWM signal to the inverter circuit. The inverter apparatus according to claim 3, wherein the current polarity detection means detects the polarity of an alternating current flowing through the inverter circuit. 4. The inverter device according to claim 1, wherein the phase difference vibration detection unit detects the vibration component of the phase difference by removing a direct current component of the phase difference detected by the phase difference detection unit. 5. The frequency correction amount calculation means increases the rotation speed correction amount when the vibration component detected by the phase difference vibration detection means is large, and decreases the rotation speed correction amount when the vibration component is small. The inverter device according to claim 1 or 3. 4. The inverter device according to claim 1, wherein the frequency correction amount calculation means calculates the frequency correction amount based on a vibration component of the phase difference and a frequency command value. The inverter device according to claim 1 or 3, wherein the frequency correction amount calculation means calculates the frequency correction amount based on a vibration component of the phase difference and a duty reference value. A motor drive inverter circuit for converting DC power into AC power and a control device for controlling the inverter circuit by a phase difference control method, wherein the control device detects a DC current flowing through the inverter circuit. Means, a phase difference detecting means for detecting a phase difference between an AC voltage and an AC current, an adjusting means for adjusting a duty reference value according to an error between the detected phase difference and a target phase difference, and A phase difference vibration detecting means for detecting a vibration component of the phase difference by removing a DC component of the phase difference detected by the phase difference detecting means; and a rotational speed correction amount of the motor based on the vibration component of the phase difference. A rotational speed correction amount calculating means for calculating, a motor rotational speed correcting means for correcting a motor rotational speed command value based on the calculated rotational speed correction amount, and the corrected motor speed. PWM signal generating means for calculating a PWM signal based on the output waveform data corresponding to the numerical command value and the adjusted duty reference value, and the control device sends the PWM signal to the inverter circuit. An inverter device characterized by outputting. An inverter circuit for driving a motor that converts DC power into AC power and a control device that controls the inverter circuit by a phase difference control method, wherein the control device detects the polarity of an AC current flowing through the inverter circuit. Depending on the error between the current polarity detection means, the phase difference detection means for detecting the phase difference between the AC voltage and the AC current when the AC current polarity is reversed, and the detected phase difference and the target phase difference Adjusting means for adjusting the duty reference value, phase difference vibration detecting means for removing the DC component of the phase difference detected by the phase difference detecting means to detect the vibration component of the phase difference, and vibration of the phase difference A rotational speed correction amount calculating means for calculating the rotational speed correction amount of the motor based on the components; and a mode for correcting the motor rotational speed command value based on the calculated rotational speed correction amount. A rotation speed correction means; and a PWM signal creation means for calculating a PWM signal based on the output waveform data corresponding to the corrected motor rotation speed command value and the adjusted duty reference value, The control device outputs the PWM signal to the inverter circuit. A compressor driving device comprising the inverter device according to claim 1. A refrigeration / air-conditioning apparatus comprising the compressor driving apparatus according to claim 11.

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