JP2009254191A - Motor controller, compressor, refrigerating apparatus, and air conditioner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor controller capable of detecting the motor startup defect in a simple configuration for the motor controller that performs a position-sensorless sine wave drive startup method. <P>SOLUTION: The motor controller determines when the startup defect decision timing is (step S1). In the event of the startup defect decision timing, the motor controller detects the information on a phase difference between a motor current signal and a motor drive voltage (step S2), and determines whether the information on the phase difference is within a normal range (step S3). The motor controller shifts to the phase difference control after a phase difference control shift timing when the detected information on the phase difference is determined to be within a normal range (step 5), while stops a motor when the detected information on the phase difference is determined to be out of a normal range (step S6). <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a motor control device for driving a motor, and a compression device, a refrigeration device, and an air conditioner equipped with the motor control device.

  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, the motor control device includes a self-limiting operation (speed feedback operation) method using a position sensor that detects the position of a rotor such as a hall element, an encoder, or a resolver.

  Moreover, it replaces with a position sensor and the method of calculating | requiring the position of a rotor indirectly by calculation based on the information of the voltage and electric current of a motor is disclosed.

  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 Patent Document 1, a high-performance sine wave drive is performed by controlling the phase difference between the motor drive voltage and the motor current signal by performing other control operation (speed open loop operation) based only on the speed command, not based on the position information. A method for realizing the above is disclosed.

  FIG. 10 is a diagram for explaining a conventional synchronous motor driving device that is controlled by the phase difference between the voltage and current of the synchronous motor.

  Referring to FIG. 10, the synchronous motor driving device uses electric power to drive a motor 1 that is a synchronous motor having a stator having three-phase (U-phase, V-phase, and W-phase) coils and a rotor having permanent magnets. AC power source 4 for supplying AC power, inverter circuit 2 and converter circuit 3 for converting AC power and DC power, current sensor 5 for detecting motor current, and motor current detection for amplifying the detected motor current and adding an offset The amplifier unit 6 includes a control unit 1000B that controls them.

  The AC power supply 4 that supplies this power, and the inverter circuit 2 and the converter circuit 3 that convert AC power and DC power constitute an inverter unit 100A.

  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 motor 1 to drive the motor 1.

  The current sensor 5 detects a motor current flowing in a specific phase (hereinafter referred to as U phase) among the phases of the coil terminals U, V, and W of the 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 1000B.

  The control unit 1000B 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.

  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 each current obtained by sampling the drive voltage phases of two motors for each period. The area of the motor current signal is calculated by integrating the 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 (target phase difference information).

  Error data between the target phase difference information and the detected phase difference information is calculated by the adder 10.

  The PI calculation unit 11 calculates proportional error data and integral error data for 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.

The rotation speed setting unit 12 sets a rotation speed command for the motor 1.
The sine wave data table 13 stores sine wave data corresponding to a predetermined rotational speed of the motor 1.

  The sine wave data creation unit 14 reads out sine wave data corresponding to the phases 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 motor 1 and the passage of time. Based on the phase sine wave data, U-phase motor drive voltage phase information is output.

  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.

  Generally, in order to execute the above phase difference control, it is necessary to start the synchronous motor normally.

  FIG. 11 is a waveform diagram of the U-phase motor current when the synchronous motor is forcibly started with a preset modulation factor and rotation speed.

  Referring to FIG. 11, when the load torque of the synchronous motor is small at the time of start-up, the synchronous motor rotates smoothly after a predetermined rotation has elapsed, and shifts to the phase difference control in a stable state.

  FIG. 12 is a waveform diagram of another U-phase motor current when the synchronous motor is forcibly started with a preset modulation factor and rotation speed.

  Referring to FIG. 12, when the load torque of the synchronous motor is too large at the time of startup, the synchronous motor performs unstable rotation even after a predetermined period of time, generates large vibrations and noises, and eventually becomes excessive. Motor current is generated. Therefore, the motor drive is stopped by the overcurrent protection device of the inverter circuit 2.

Patent Document 2 discloses a method for detecting a state where the motor does not start normally when the load torque is too large.
Japanese Patent Laid-Open No. 2001-112287 Japanese National Patent Publication No. 10-501057

  However, in the method disclosed in Patent Document 2, as a method for detecting an abnormality at the time of starting the motor, a method is disclosed in which the number of revolutions is detected and the lock state is determined when the number of revolutions is lower than a predetermined number. However, in the starting method of the position sensorless sine wave drive as shown in Patent Document 1, 180-degree sine wave energization is used, and in this drive method, there is no energization pause period, so that the induced voltage cannot be detected, and the rotational position Cannot be detected, and it is not possible to detect a motor start error by detecting a current error at startup.

  The present invention has been made to solve the above-described problems, and a motor control apparatus that executes a position sensorless sine wave drive start method can detect a motor start abnormality with a simple configuration. It is an object of the present invention to provide a motor control device, and a compression device, a refrigeration device, and an air conditioner equipped with the motor control device.

  A motor control device according to the present invention is a motor control device that drives and controls a synchronous motor including a plurality of phase motor coils, and detects a motor current of at least one phase of the plurality of phases to detect a motor current signal. A motor current detection unit for outputting a phase difference detection unit for detecting a phase difference between a motor current signal output from the motor current detection unit and a corresponding motor drive voltage among a plurality of phases and outputting phase difference information; And an inverter unit for energizing each phase of the motor coil, and an activation abnormality determining unit for detecting the occurrence of the activation abnormality of the synchronous motor based on the phase difference information in a predetermined period for forcibly starting the synchronous motor.

  Another motor control device according to the present invention is a motor control device that drives and controls a synchronous motor having a plurality of phase motor coils, and includes an inverter unit for energizing each phase motor coil, and an inverter from the synchronous motor A direct current detection unit that detects a direct current flowing through the motor, a motor current detection unit that outputs a motor current signal based on the direct current detected by the direct current detection unit, and a motor current output from the motor current detection unit Based on the phase difference information in a predetermined period for forcibly starting the synchronous motor, and a phase difference detector that detects the phase difference between the signal and the corresponding motor drive voltage of the plurality of phases and outputs the phase difference information A startup abnormality determining unit that detects occurrence of a startup abnormality of the synchronous motor.

  Still another motor control device according to the present invention is a motor control device that drives and controls a synchronous motor including a plurality of phase motor coils, and is configured to control at least one phase of the plurality of phase motor currents. A motor current polarity detection unit that detects a polarity and outputs a motor current polarity signal based on the detection result; a motor current polarity signal output from the motor current polarity detection unit; and a corresponding motor drive voltage of a plurality of phases The phase difference detection unit that detects the phase difference and outputs the phase difference information, the inverter unit that energizes the motor coil of each phase, and the synchronization based on the phase difference information in a predetermined period for forcibly starting the synchronous motor A start-up abnormality determining unit that detects occurrence of a start-up abnormality of the motor.

  Preferably, the supply of power to the synchronous motor is stopped based on the detection of the start abnormality by the start abnormality determining unit.

  The compression apparatus which concerns on this invention is provided in the compression part which compresses a refrigerant | coolant about the said synchronous motor, and is provided with said motor control apparatus which drives and controls a synchronous motor.

A refrigeration apparatus according to the present invention includes the above-described compression apparatus, a condenser, and a cooler.
An air conditioner according to the present invention includes the above-described compression device, a condenser, and a cooler.

  A motor control device according to the present invention includes a start abnormality determination unit that detects occurrence of a start abnormality of a synchronous motor based on phase difference information between a motor current signal and a motor drive voltage in a predetermined period for forcibly starting the synchronous motor. With.

  This configuration makes it easy to start abnormalities when starting a synchronous motor without using a sensor that detects the rotor position in motor drive with 180 ° energization, including low noise, low vibration, and high efficiency sinusoidal energization. Can be detected by simple configuration and control. Further, even when the load torque at the time of startup is too large, it is possible to prevent application of excessive current and generation of large vibration and noise.

  Embodiments of the present invention will be described below with reference to the drawings. In the following description, the same parts and components are denoted by the same reference numerals. Their names and functions are also the same.

(Embodiment 1)
FIG. 1 is a schematic block diagram illustrating a synchronous motor drive device according to Embodiment 1 of the present invention.

  Referring to FIG. 1, a synchronous motor driving apparatus includes an inverter unit 100A that drives a motor 1 that is a synchronous motor having a stator having three-phase (U-phase, V-phase, and W-phase) coils and a rotor having permanent magnets. A current sensor 5 for detecting a motor current, a motor current detection amplifier unit 6 for amplifying the detected motor current and adding an offset, and a control unit 100B are provided. The functional block of the control unit 100B can be realized by loading a software program into a CPU (Central Processing Unit), or can be realized by hardware.

  Inverter unit 100A includes an AC power supply 4 that supplies power, and an inverter circuit 2 and a converter circuit 3 that convert AC power and DC power.

  As described above, 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 motor 1 to drive the motor 1.

  The current sensor 5 detects a motor current flowing in a specific phase (hereinafter referred to as U phase) among the phases of the coil terminals U, V, and W of the motor 1. In this example, a case where a motor current flowing in one specific phase is detected will be described.

  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 100B.

  The control unit 100B 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, PWM creation unit 15, and startup abnormality determination unit 16.

  Similar to the method described in Japanese Patent Laid-Open No. 2001-112287 described above, the phase difference detection unit 8 performs A / D conversion on the motor current signal provided from the motor current detection amplifier unit 6 at a predetermined timing. The area of the motor current signal is calculated by integrating the current sampling data obtained by sampling the drive voltage phases of the two motors for each period. The calculated area ratio of the areas of the two motor current signals is output as phase difference information that is a phase difference between the motor drive voltage and the motor current signal.

  The target phase difference information storage unit 9 stores target phase difference information (target phase difference information).

  Error data between the target phase difference information and the detected phase difference information is calculated by the adder 10.

  The PI calculation unit 11 calculates proportional error data and integral error data for 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.

The rotation speed setting unit 12 sets a rotation speed command for the motor 1.
The sine wave data table 13 stores sine wave data corresponding to a predetermined rotational speed of the motor 1.

  The sine wave data creation unit 14 reads out sine wave data corresponding to the phases 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 motor 1 and the passage of time. Based on the phase sine wave data, U-phase motor drive voltage phase information is output. Although the motor drive waveform is a sine wave configuration, the sine waveform enables smooth motor current supply, thereby suppressing vibration and noise.

  The PWM generation unit 15 generates a PWM waveform based on the sine wave data and the duty reference value, and outputs the generated PWM waveform to the drive elements of the synchronous motor terminals U, V, and W of the inverter circuit 2. To do.

  The current sensor 5 may be a so-called current sensor constituted by a coil and a Hall element, or may be a current transformer. Further, by detecting the motor current of each phase as well as one phase, detection with higher accuracy is possible.

  The phase difference detection unit 8 calculates the area ratio of the two motor current signals detected during the phase period of the two motor drive voltages, and the result is a phase difference that is the phase difference between the motor drive voltage and the motor current signal. Information. The PI calculation unit 11 performs PI calculation on the error amount between the phase difference information and the target phase difference information, and the PWM generation unit 15 calculates the error from the duty reference value that is the output and the sine wave data that is separately obtained from the rotation command. The synchronous motor 1 is driven by calculating the output duty ratio every time, creating a PWM signal, and applying it to the motor coil via the inverter circuit 2.

  That is, the magnitude of the drive voltage (duty width of the PWM duty) is determined by a phase difference control feedback loop for controlling the motor current phase difference with respect to the motor drive voltage (output duty) to be constant, and the synchronous motor 1 is rotated in a desired rotation. It is possible to drive and control the motor with a desired phase difference and a desired number of rotations in order to rotate the number.

Next, a method for detecting a start abnormality when starting the synchronous motor 1 will be described.
In this example, the control unit 100B is further provided with a startup abnormality determination unit 16.

  The start abnormality determination unit 16 receives the phase difference information from the phase difference detection unit 8, determines whether or not there is a start abnormality, and outputs the result to the PWM creation unit 15.

  The PWM creation unit 15 controls the generation of the PWM waveform based on the determination result from the startup abnormality determination unit 16. Specifically, when it is determined that there is a start abnormality based on the determination result from the start abnormality determination unit 16, the generation of the PWM waveform is stopped. On the other hand, if it is determined that there is no startup abnormality, a PWM waveform is generated as usual.

  FIG. 2 is a flowchart for determining a startup abnormality in control unit 100B according to the first embodiment of the present invention.

  Referring to FIG. 2, first, it is determined whether or not it is a start abnormality determination timing (step S1). As will be described later, in this example, it is determined whether or not the activation is abnormal after a predetermined period of time has elapsed since the activation. It waits until it becomes a starting abnormal timing, and when it becomes a starting abnormal timing, phase difference information is detected (step S2). Specifically, the phase difference information output from the phase difference detection unit 8 is detected by the activation abnormality determination unit 16.

Then, it is determined whether or not the phase difference information is within a normal range (step S3).
In step S3, when the activation abnormality determination unit 16 determines that the detected phase difference information is within the normal range, the process proceeds to step S4.

  On the other hand, when the start abnormality determination unit 16 determines in step S3 that the phase difference information is not within the normal range, the motor is stopped (step S6). Specifically, a determination result indicating a start abnormality is output from the start abnormality determination unit 16 to the PWM creation unit 15. Then, the PWM creating unit 15 receives the input of the determination result signal indicating the start abnormality from the start abnormality determining unit 16 and stops generating the PWM waveform. As a result, the operation of the circuit elements of the inverter circuit 2 of the inverter unit 100A is stopped, and the motor is stopped. And it ends.

  If it is determined in step S3 that the phase difference information is within the normal range, it is determined whether it is the phase difference control transition timing (step S4).

  The process waits in step S4 until the phase difference control shift timing is reached, and shifts to phase difference control when the phase difference control shift timing is reached (step S5). And it ends.

  FIG. 3 is a waveform diagram of a U-phase motor current signal and a U-phase voltage phase signal when the synchronous motor is forcibly started with a preset modulation factor and rotation speed.

Here, a waveform in the case where the load torque of the synchronous motor is small at the time of startup is shown.
Referring to FIG. 3 (a), in this example, the synchronous motor is forcibly started at a preset modulation factor and number of rotations for four cycles of the U-phase voltage as a forced rotation section. And after that, the case where it becomes a phase difference control section is shown. That is, in this example, the phase difference control transition timing is set after four cycles of the U-phase voltage.

  The start abnormality determination timing is set after three cycles of the U-phase voltage in the forced rotation section. In this example, the case where the start abnormality determination timing is set after three cycles of the U-phase voltage will be described as an example. However, the present invention is not limited to this, and forced rotation ends after the first phase difference is detected. It is possible to execute in the meantime.

  The phase difference detection unit 8 detects a phase difference between the motor current signal output from the motor current detection amplifier unit 6 and the motor drive voltage output from the sine wave data generation unit 14 at the start abnormality determination timing. It should be noted that when the motor drive voltage is in the lead phase with respect to the motor current signal, a negative value is assumed. In the case of a delayed phase, a positive value is assumed. 0 for in-phase.

  Then, the phase difference detection unit 8 detects the phase difference, and the activation abnormality determination unit 16 determines whether or not the phase difference is within the normal range. In this example, it is determined whether or not the phase difference in the phase difference detection unit 8 is within a range of 20 degrees to 60 degrees that is within a preset normal range.

  Referring to FIG. 3B, in this example, a case where a part of the motor drive voltage and the motor current signal is enlarged is described.

  According to the flowchart of FIG. 2, the phase difference information is detected when the activation abnormality determination timing is reached. Specifically, as described above, the phase difference (phase difference information) between the motor current signal output from the motor current detection amplifier unit 6 and the motor drive voltage is detected. In this example, it is assumed that the phase difference between the motor drive voltage and the motor current signal is about 40 degrees.

  Accordingly, the activation abnormality determination unit 16 determines that the phase difference information is within the normal range, and thus shifts to normal phase difference control when the phase difference control shift timing (step S4) is reached as described above.

  FIG. 4 is a waveform diagram of another U-phase motor current when the synchronous motor is forcibly started with a preset modulation factor and rotation speed.

Here, a waveform when the load torque of the synchronous motor is large at the time of start-up is shown.
With reference to Fig.4 (a), in this example, after the starting abnormality determination timing, the case where the motor is in a stopped state is shown.

  Referring to FIG. 4B, here, a part of the motor drive voltage and the motor current signal which are enlarged is described.

  According to the flowchart of FIG. 2, the phase difference information is detected when the activation abnormality determination timing is reached. Specifically, as described above, the phase difference (phase difference information) between the motor current signal output from the motor current detection amplifier unit 6 and the motor drive voltage is detected. In this example, it is assumed that the phase difference between the motor drive voltage and the motor current signal is about 10 degrees.

  Accordingly, since the activation abnormality determination unit 16 determines that the phase difference information is not within the normal range, that is, the activation abnormality, the activation abnormality determination unit 16 notifies the PWM creation unit to that effect. Then, the generation of the PWM waveform is stopped and the motor is stopped.

  If it is determined by this method that the start is abnormal, the generation of the PWM waveform can be stopped, so that unstable rotation that occurs when the load torque of the synchronous motor is too large at the start is stopped. It is possible to suppress large vibrations and noises.

  Note that the range of the phase difference information that is determined to be normal startup is executed by appropriately performing experiments under various load conditions and measuring values when the synchronous motor 1 is stably started.

  In this example, the area ratio of the two motor current signals detected in the phase period of the two motor drive voltages is calculated in the phase difference control section, and this result is used as the phase difference information to obtain the phase difference. The configuration for executing the control of the synchronous motor based on the error amount between the information and the target phase difference information has been described. However, the configuration is not limited to this method, and the synchronous motor can be controlled according to another method.

(Embodiment 2)
In the first embodiment described above, the method of detecting an abnormality at the start-up by detecting the motor current of each phase of the coil terminals U, V, W of the synchronous motor 1 has been described.

  In the second embodiment of the present invention, a method for estimating the motor current based on the current supplied to the inverter circuit 2 will be described.

Specifically, the current flowing between the converter circuit 3 and the inverter circuit 2 is detected.
FIG. 5 is a schematic block diagram illustrating a synchronous motor driving device according to the second embodiment of the present invention.

  Referring to FIG. 5, the synchronous motor drive device is an inverter unit 100 </ b> A # that drives a motor 1 that is a synchronous motor including a stator having three-phase (U-phase, V-phase, and W-phase) coils and a rotor having permanent magnets. A DC current detection amplifier unit 22 that detects a DC current flowing through the current detection resistor 21 based on an applied voltage applied to the current detection resistor 21 provided between the converter circuit 3 and the inverter circuit 2, and a control unit 100B # With.

  Unlike the inverter unit 100A, the inverter unit 100A # is provided with a current detection resistor 21 between the converter circuit 3 and the inverter circuit 2.

  Control unit 100B # is different from control unit 100B in that motor current estimation unit 23 is further provided. Since the other points are the same, detailed description thereof will not be repeated.

  The direct current detection amplifier unit 22 detects the direct current flowing through the inverter circuit 2 based on the voltage generated at both ends of the current detection resistor 21.

  The direct current detection amplifier unit 22 amplifies the detected direct current and outputs it as a direct current signal to the motor current estimation unit 23 of the control unit 100B #.

  The motor current estimating unit 23 obtains a change in the DC current from the input DC current signal by the current change calculation means according to the method described in JP-A-8-19263, and calculates the change in the DC current signal. The motor current signal is estimated and calculated by the distribution calculation means.

FIG. 6 is a schematic block diagram illustrating the configuration of the motor current estimation unit 23.
Referring to FIG. 6, current id is detected by DC current detection amplifier unit 22. The pair of sample and hold circuits 113 and 114 are sampled and controlled alternately according to the switching pattern based on the PWM waveform, and sample the detected current id from the DC current detection amplifier unit 22 and temporarily store it.

  The timing control circuit 115 obtains the switching timing signal of each phase arm from the PWM waveform signal generated by the PWM generator 15 that controls the on / off of each phase arm of the inverter circuit 2. Based on this signal, the sampling timing signals of the sample hold circuits 113 and 114 are obtained. Then, sampling is performed based on the sampling timing signal.

  Thus, when one of the sample and hold circuits 113 and 114 samples the current id immediately before switching of each phase arm, the other samples the current id immediately after switching.

  The subtraction circuit 116 obtains a difference Δid between the currents id1 and id2 sampled by the sample and hold circuits 113 and 114.

  The distribution calculation circuit 117 distributes the current difference signal Δid for each phase, and obtains a current detection signal for each phase. For this signal distribution, a timing signal for each phase from the timing control circuit 115 is used.

  Then, an estimated motor current signal for each phase can be obtained from the distribution calculation circuit 117.

  By inputting the estimated motor current signal to the phase difference detection unit 8, it is possible to detect an abnormality at the start-up according to the same method as described in the first embodiment.

  Specifically, the phase difference detection unit 8 compares the estimated motor current signal output from the motor current estimation unit 23 and the motor drive voltage output from the sine wave data creation unit 14 at the start abnormality determination timing. Detect phase difference. Then, the activation abnormality determination unit 16 receives the phase difference information from the phase difference detection unit 8, determines whether or not it is an activation abnormality, and outputs the result to the PWM creation unit 15.

  The PWM creation unit 15 controls the generation of the PWM waveform based on the determination result from the startup abnormality determination unit 16. Specifically, when it is determined that there is a start abnormality based on the determination result from the start abnormality determination unit 16, the generation of the PWM waveform is stopped. On the other hand, if it is determined that there is no startup abnormality, a PWM waveform is generated as usual.

  In the configuration of the second embodiment, by providing the motor current estimation unit 23, the motor current can be detected by the estimation calculation without providing the current sensor 5, so that the cost can be reduced.

  The method for estimating the motor current is not limited to the above method, and other methods can be adopted.

(Embodiment 3)
FIG. 7 is a schematic block diagram illustrating a synchronous motor drive device according to the third embodiment of the present invention.

  Referring to FIG. 7, the synchronous motor drive device according to the third embodiment of the present invention is provided with current polarity detection means 37 instead of current sensor 5 as compared with the synchronous motor drive device of the first embodiment. Is different from the motor current detection amplifier unit 6 in that a motor current polarity detection unit 31 is provided. The other points are the same as those in the first embodiment.

The current polarity detection unit 37 detects the polarity of the motor current flowing in the U phase of the motor 1.
The motor current polarity detection unit 31 generates an AC current polarity signal based on the polarity of the U-phase AC current of the motor winding terminal flowing in the inverter circuit 2 detected by the current polarity detection unit 37, and the phase difference detection unit 8 is output.

  The phase difference detection unit 8 detects the phase difference between the AC voltage and the AC current polarity signal when the AC current polarity is inverted based on the AC current polarity signal output from the motor current polarity detection unit 31. Thereby, the phase difference information between the motor drive voltage and the motor current signal can be detected only from the current polarity information.

  FIG. 8 is a waveform diagram of a U-phase motor current signal, a U-phase voltage phase signal, and a U-phase AC current polarity signal when the synchronous motor is forcibly started with a preset modulation factor and rotation speed. It is.

  With reference to Fig.8 (a), here, the waveform in case the load torque of a synchronous motor is small at the time of starting is shown. Here, the U-phase alternating current polarity signal has a waveform corresponding to the polarity of the U-phase current.

  According to the flowchart of FIG. 2, the phase difference information is detected when the activation abnormality determination timing is reached. Specifically, as described above, the phase difference (phase difference information) between the U-phase AC current polarity signal output from the motor current polarity detection unit 31 and the motor drive voltage is detected. In this example, it is assumed that the phase difference between the motor drive voltage and the U-phase AC current polarity signal is about 40 degrees.

  Accordingly, the activation abnormality determination unit 16 determines that the phase difference information is within the normal range, and thus shifts to normal phase difference control when the phase difference control shift timing (step S4) is reached as described above.

  Referring to FIG. 8B, here, a waveform is shown when the load torque of the synchronous motor is large at the time of startup.

Here, the U-phase alternating current polarity signal has a waveform corresponding to the polarity of the U-phase current.
According to the flowchart of FIG. 2, the phase difference information is detected when the activation abnormality determination timing is reached. Specifically, as described above, the phase difference (phase difference information) between the U-phase AC current polarity signal output from the motor current polarity detection unit 31 and the motor drive voltage is detected. In this example, it is assumed that the phase difference between the motor drive voltage and the U-phase alternating current polarity signal is about 10 degrees.

  Accordingly, since the activation abnormality determination unit 16 determines that the phase difference information is not within the normal range, that is, the activation abnormality, the activation abnormality determination unit 16 notifies the PWM creation unit to that effect. Then, the generation of the PWM waveform is stopped and the motor is stopped.

  FIG. 9 is a diagram illustrating a case where the synchronous motor according to the embodiment of the present invention is applied to refrigeration cycle apparatus 125.

  With reference to FIG. 9, the refrigeration cycle apparatus 125 includes a condenser 123, a compression apparatus 126, and a cooler 124. The compression device 126 includes a compression unit 127 driven by the synchronous motor 1. The compression device can be applied to either a so-called reciprocating compression device or a rotary compression device.

  The compression unit 127 is driven by the synchronous motor 1, the refrigerant is compressed to a high temperature and a high pressure, and supplied to the condenser 123. In the condenser 123, the refrigerant is liquefied while dissipating heat. The liquefied refrigerant is vaporized by the cooler 124 and takes heat away from the surroundings. Then, the refrigerant again returns to the compression device 126 and is compressed.

  In the present example, the configuration in which the synchronous motor 1 is applied to the compressor and further incorporated into the refrigeration apparatus has been described, but it can also be applied to an air conditioner.

  In the above description, the configuration in which the generation of the PWM waveform is stopped when it is determined that the start is abnormal has been described. However, the present invention is not limited to this, and means capable of stopping the supply of power to the synchronous motor. If it is. For example, a configuration may be provided in which means for stopping the supply from the AC power supply 4 is provided when it is determined that there is a start-up abnormality.

  In the above-described embodiment, the motor current flowing in one specific phase is detected as the phase difference information, and the start abnormality determination based on the phase difference information between the motor drive voltage and the motor current signal has been described. Specifically, the case where the phase difference between the U-phase voltage and the U-phase current is detected has been described. However, the present invention is not limited to this, and the determination can be performed using the V-phase and the W-phase. It is also possible to detect motor currents flowing in a plurality of phases, respectively, and execute a start abnormality determination using phase difference information with motor drive voltages corresponding to the respective phases. In addition, the determination of the activation abnormality is not limited to one, but it is also possible to increase the accuracy of the determination of the activation abnormality by performing a plurality of activation abnormality determinations. Moreover, it is also possible to calculate the average value of the phase difference information of a plurality of phases and execute the start abnormality determination. The same applies to the case where an alternating current polarity signal is used.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

It is a schematic block diagram explaining the synchronous motor drive device according to Embodiment 1 of the present invention. It is a flowchart which determines the starting abnormality in the control part 100B according to Embodiment 1 of this invention. FIG. 6 is a waveform diagram of a U-phase motor current signal and a U-phase voltage phase signal when a synchronous motor is forcibly started with a preset modulation factor and rotation speed. It is a wave form diagram of another U phase motor current at the time of starting a synchronous motor compulsorily with a preset modulation factor and number of rotations. It is a schematic block diagram explaining the synchronous motor drive device according to Embodiment 2 of the present invention. 3 is a schematic block diagram illustrating a configuration of a motor current estimation unit 23. FIG. It is a schematic block diagram explaining the synchronous motor drive device according to Embodiment 3 of the present invention. FIG. 6 is a waveform diagram of a U-phase motor current signal, a U-phase voltage phase signal, and a U-phase AC current polarity signal when a synchronous motor is forcibly started with a preset modulation factor and rotation speed. It is a figure explaining the case where the synchronous motor according to embodiment of this invention is applied to the refrigerating-cycle apparatus 125. FIG. It is a figure explaining the conventional synchronous motor drive device controlled by the phase difference of the voltage and electric current of a synchronous motor. FIG. 6 is a waveform diagram of a U-phase motor current when a synchronous motor is forcibly started with a preset modulation factor and rotation speed. It is a wave form diagram of another U phase motor current at the time of starting a synchronous motor compulsorily with a preset modulation factor and number of rotations.

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, 8 Phase difference detection part, 9 Target phase difference information storage part, 10 Adder part, 11 PI calculating part, 12 rotational speed setting unit, 13 sine wave data table, 14 sine wave data creation unit, 15 PWM creation unit, 16 startup abnormality determination unit, 21 current detection resistor, 22 DC detection amplifier unit, 23 motor current estimation unit, 31 motor current Polarity detection unit, 37 Current polarity detection means, 100A, 100A # inverter unit, 100B, 100B # control unit, 123 condenser, 124 cooler, 125 refrigeration cycle device, 126 compression device, 127 compression unit.

Claims (7)

A motor control device that drives and controls a synchronous motor having a motor coil of a plurality of phases,
A motor current detector that detects a motor current of at least one of the plurality of phases and outputs a motor current signal; and
A phase difference detection unit that detects a phase difference between a motor current signal output from the motor current detection unit and a corresponding motor drive voltage among the plurality of phases and outputs phase difference information;
An inverter for energizing the motor coils of each phase;
A motor control apparatus comprising: a start abnormality determination unit that detects occurrence of a start abnormality of the synchronous motor based on the phase difference information in a predetermined period for forcibly starting the synchronous motor. A motor control device that drives and controls a synchronous motor having a motor coil of a plurality of phases,
An inverter for energizing the motor coils of each phase;
A direct current detection unit for detecting a direct current flowing from the synchronous motor to the inverter unit;
A motor current detector that outputs a motor current signal based on the DC current detected by the DC current detector;
A phase difference detection unit that detects a phase difference between a motor current signal output from the motor current detection unit and a corresponding motor drive voltage among the plurality of phases and outputs phase difference information;
A motor control apparatus comprising: a start abnormality determination unit that detects occurrence of a start abnormality of the synchronous motor based on the phase difference information in a predetermined period for forcibly starting the synchronous motor. A motor control device that drives and controls a synchronous motor having a motor coil of a plurality of phases,
A motor current polarity detector for detecting a polarity of a motor current of at least one phase of the motor currents of the plurality of phases and outputting a motor current polarity signal based on the detection result;
A phase difference detection unit that detects a phase difference between a motor current polarity signal output from the motor current polarity detection unit and a corresponding motor drive voltage among the plurality of phases and outputs phase difference information;
An inverter for energizing the motor coils of each phase;
A motor control apparatus comprising: a start abnormality determination unit that detects occurrence of a start abnormality of the synchronous motor based on the phase difference information in a predetermined period for forcibly starting the synchronous motor.   The motor control device according to any one of claims 1 to 3, wherein supply of electric power to the synchronous motor is stopped based on detection of a start-up abnormality by the start-up abnormality determination unit. The synchronous motor is provided in a compression device that compresses the refrigerant,
The compression apparatus provided with the motor control apparatus as described in any one of Claims 1-4 which drive and control the said synchronous motor.   A refrigeration apparatus comprising the compression apparatus according to claim 5, a condenser, and a cooler.   An air conditioner comprising the compression device according to claim 5, a condenser, and a cooler.

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