JP3577245B2 - Motor start control device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a motor start control device, and more particularly to a motor start control device capable of surely starting a synchronous motor used in a compressor of an air conditioner without detecting the position of the synchronous motor.
[0002]
[Prior art]
BACKGROUND ART Conventionally, there is a motor start control device for starting a motor. Among conventional motor start-up control devices, a motor start-up control device that does not use a motor position detector and starts a motor by so-called senseless driving usually suspends energization of a drive voltage waveform supplied to a plurality of coils constituting the motor. There is a period.
[0003]
This type of motor start control device generates a rotating magnetic field at a motor coil terminal at a predetermined frequency and a predetermined PWM duty (drive voltage) regardless of the positional relationship between the motor rotor and the stator, and generates a frequency or a duty of the PWM duty. By gradually increasing the reference value, a so-called forced excitation operation (or synchronous operation) for synchronizing the rotation of the motor with the rotating magnetic field is performed.
[0004]
Then, the back electromotive voltage generated at each motor coil terminal due to the rotation of the motor is detected during the above-described power supply suspension period, and the startup is completed after confirming the detection. After the start-up is completed, switching to motor driving based on the back electromotive voltage (hereinafter referred to as back electromotive operation) is performed, and normal motor driving is performed.
[0005]
On the other hand, a "brushless motor control method and apparatus (Japanese Patent Application Laid-Open No. 7-87783)" (referred to as Document 1) detects a motor position when starting a motor, and outputs a motor position detection signal and a motor drive signal. A method and an apparatus for controlling a motor by comparing a phase difference with a voltage and reducing the phase difference are disclosed.
[0006]
[Problems to be solved by the invention]
By the way, as described above, the conventional senseless drive motor start control device needs to detect the back electromotive voltage generated at each motor coil terminal, and therefore, the drive waveform supplied to each motor coil terminal has a non-operating period. Is provided. The driving waveform at this time is generally a so-called 120 ° rectangular wave in many cases. This 120 ° rectangular wave is one in which energization is performed at a constant PWM duty during the energization period, and an energization suspension period and a constant energization period (PWM duty) are alternately repeated.
[0007]
However, in such a conventional motor start control device, there is a problem that a large noise or vibration is generated because the motor torque generated between the power supply suspension period and the power supply period fluctuates. Since these are particularly large at the time of starting when the rotation speed of the motor is small, it is difficult to start the motor itself.
[0008]
In addition, since the power supply suspension period exists, the magnet magnetic flux of the motor rotor cannot be used effectively, and the motor efficiency is reduced.
[0009]
In addition, since the motor rotation speed is low at the time of the electromotive force and immediately after the electromotive force, the back electromotive voltage has a low amplitude (0 volt at the time of starting) in proportion thereto. For this reason, in order to accurately detect the back electromotive voltage, it is necessary to increase the motor speed. However, if the rotation speed is increased to a high speed only by the forced excitation operation, the motor energization timing is not known, which may lead to a stop of the motor (step-out), and the reliability is low. If the motor stops suddenly due to step-out, a large load is applied to the internal elements.
[0010]
Normally, the motor drive system and the control system are insulated for noise removal to obtain signals. Similarly, in order to accurately detect the back electromotive voltage, the back electromotive voltage signal also needs insulation for noise removal. However, in order to insulate the back electromotive force signal, a high-performance filter is required, which leads to an increase in circuit cost.
[0011]
In addition, since the transition from the start to the normal operation is switched after a certain period of time regardless of the state of the motor, the start may not be performed depending on the state of the motor load.
[0012]
In the case of using the device of the above-mentioned document 1, a means for detecting the motor position is required, which leads to an increase in cost. In addition, when the motor position is detected from the back electromotive voltage, an unstable phase difference is detected because the motor itself vibrates during the electromotive force, in addition to the various problems related to the detection of the back electromotive voltage described above. There's a problem. Therefore, controlling the drive signal by this causes a false detection.
[0013]
As described above, in the conventional motor start control device, since the back electromotive force is used, the vibration and noise are large, the efficiency is low, and the state of the motor during the electromotive force is unknown. Sex was low.
[0014]
The present invention has been made in order to solve such a problem, and provides a motor start control device capable of reliably starting with low vibration, low noise, and high efficiency.
[0015]
[Means for Solving the Problems]
this A motor start control device according to the present invention is a motor start control device that controls a synchronous motor, a motor current detection unit that detects a motor current flowing through a coil of the synchronous motor, a motor current and a drive voltage supplied to the coil. Detect phase difference information Phase difference Detection means and phase difference information Variation Based on synchronous motor Means for determining whether or not is in a stable startup completion state, based on the determination result of the determination means And control means for controlling the drive voltage applied to the terminals of the coil and the energizing frequency to the terminals of the coil.
[0016]
Therefore, this According to the motor start control device, the phase difference between the motor drive voltage and the motor current Variation , The rotation state of the motor can be detected, and the motor can be started and driven. And the phase difference information Variation , The synchronous motor is in a stable startup completed state Determine whether or not I do. Therefore, the start-up can be reliably completed by the sensorless system without the motor position detector, and stable start-up without failure is realized. Since the sensorless method is adopted, a position detector is not required, and cost reduction is realized.
[0017]
Preferably The phase difference information is the area of the motor current waveform during a predetermined phase period of the drive voltage waveform.
[0018]
in this case By calculating the area of the motor current waveform, the phase difference can be easily calculated. In addition, since the phase difference information is detected according to the area of the motor current, it is superior in noise resistance compared to the edge detection method such as zero cross detection, and the phase difference information is reliably detected without being affected by the fluctuation of the motor current. It is possible to do. Therefore, a malfunction is avoided and a stable start is realized.
[0019]
Also preferably The phase difference information is a ratio between a first area of the motor current waveform in a first predetermined phase period of the drive voltage waveform and a second area of the motor current waveform in a second predetermined phase period of the drive voltage waveform.
[0020]
in this case By calculating the area ratio of the motor current waveform, the phase difference can be accurately and easily calculated. In addition, since the phase difference information is detected according to the area of the motor current, it is superior in noise resistance compared to the edge detection method such as zero cross detection, and the phase difference information is reliably detected without being affected by the fluctuation of the motor current. It is possible to do. Therefore, a malfunction is avoided and a stable start is realized.
[0021]
Also preferably The area is obtained by integrating values obtained by A / D sampling the motor current at predetermined intervals within a predetermined phase period.
[0022]
in this case The area can be calculated by sampling using a simple circuit configuration. Thereby, the configuration of the control system can be simplified and the cost can be reduced.
[0023]
Also preferably , The first area is obtained by integrating values obtained by performing A / D sampling of the motor current at predetermined intervals during a first predetermined phase period, and the second area is obtained by: The value obtained by A / D sampling the motor current at predetermined intervals is integrated.
[0024]
in this case With a simple circuit configuration, the area can be calculated by sampling, and further the area ratio can be calculated. Thereby, the configuration of the control system can be simplified and the cost can be reduced.
[0027]
Also preferably, the judgment The means is such that the synchronous motor is in an unstable rotation state based on the dispersion of the phase difference information. Determine whether or not And unstable rotation Is determined to be The synchronous motor is in a stable start completion state based on the dispersion of the phase difference information Determine whether or not I do.
[0028]
in this case Since the startup completion state (stable rotation) after unstable rotation can be detected more reliably, failure to start the motor can be avoided, and the reliability of the startup determination is further increased. That is, high reliability can be realized.
[0029]
Also preferably, the judgment Means for comparing the variation of the phase difference information with a predetermined value, But Stable startup completed Determine whether or not I do.
[0030]
in this case In addition, it is possible to accurately detect the startup completion state in which the variation in the phase difference is small.
[0031]
Also preferably determined Means for comparing the variation of the phase difference information with the first predetermined value, But Unstable rotation state Determine whether or not By comparing the variation of the phase difference information with the second predetermined value, the synchronous motor But Stable startup completed Determine whether or not I do.
[0032]
in this case After accurately detecting an unstable rotation state having a large phase difference variation, a stable rotation state (startup completed state) having a small phase difference variation can be accurately detected.
[0033]
Also preferably The control means sets the energizing frequency to a predetermined value and changes the duty reference value of the drive voltage with time from the start of the synchronous motor to the completion of the stable start.
[0034]
in this case By changing the duty reference value, it is possible to quickly shift to the startup completed state (stable rotation state) and shorten the time until the startup is completed. In addition, since the start completion state (stable rotation) can be detected after detecting the unstable rotation state, failure of starting the motor can be avoided.
[0035]
Also preferably The control means sets the drive voltage to a predetermined value and changes the energizing frequency with time from the start of the synchronous motor to the stable start completion state.
[0036]
in this case By changing the energizing frequency, it is possible to quickly shift to the start-up completed state (stable rotation state) and shorten the time until the start-up is completed. In addition, since the start completion state (stable rotation) can be detected after detecting the unstable rotation state, failure of starting the motor can be avoided.
[0037]
Also preferably The control means sets each of the energizing frequency and the drive voltage to the value at the time of stable start of the synchronous motor from the start of start of the synchronous motor to the stable start completion state.
[0038]
in this case Thus, the state quickly shifts to the start-up completed state (stable rotation state), and the time until the start-up is completed can be shortened. In addition, since the start completion state (stable rotation) can be detected after detecting the unstable rotation state, failure of starting the motor can be avoided.
[0039]
Also preferably The control means sets the amount of change in the duty reference value of the drive voltage according to the variation in the phase difference information when the synchronous motor is started.
[0040]
in this case By changing the duty reference value in accordance with the variation in the phase difference information, it is possible to quickly shift to the start-up completed state (stable rotation state) and shorten the time until the start-up is completed. Further, by setting the amount of change according to the variation of the phase difference, a state in which there are many vibrations or step-outs can be quickly passed, and the life of the motor can be extended, and the peripheral devices can be highly reliable.
[0041]
Also preferably When the synchronous motor is started, the control means sets the amount of change in the duty reference value of the drive voltage according to the state of the synchronous motor.
[0042]
in this case By changing the duty reference value according to the state of the synchronous motor, it is possible to quickly shift to the start-up completed state (stable rotation state) and to shorten the time until the start-up is completed. In addition, by setting the amount of change according to the state of the synchronous motor, it is possible to quickly pass through a state where there are many vibrations or loss of synchronism, and a longer life of the motor and high reliability of peripheral devices can be realized.
[0043]
Also preferably The control means has a limit value for the duty reference value of the drive voltage.
[0044]
in this case , The duty of the PWM is limited, so that it is possible to prevent the current from being too large, causing an overcurrent to flow into the inverter or the motor and damaging them. Therefore, the reliability of the device is improved.
[0045]
Also preferably When the synchronous motor is started, the control means sets the amount of change in the energizing frequency according to the variation in the phase difference information.
[0046]
in this case By changing the energizing frequency in accordance with the variation in the phase difference information, it is possible to quickly shift to the start-up completed state (stable rotation state) and shorten the time until the start-up is completed. Further, by setting the amount of change according to the variation of the phase difference, a state in which there are many vibrations or step-outs can be quickly passed, and the life of the motor can be extended, and the peripheral devices can be highly reliable.
[0047]
Also preferably When the synchronous motor is started, the control means sets the amount of change in the energizing frequency according to the state of the synchronous motor.
[0048]
in this case By changing the energizing frequency in accordance with the state of the synchronous motor, it is possible to quickly shift to the start-up completed state (stable rotation state) and to shorten the time until the start-up is completed. In addition, by setting the amount of change according to the state of the synchronous motor, it is possible to quickly pass through a state where there are many vibrations or loss of synchronism, and a longer life of the motor and high reliability of peripheral devices can be realized.
[0049]
Also preferably , The control means By the judgment means Synchronous motor But Stable startup completed Is determined to be After that, the synchronous motor is driven so that the phase difference information becomes a predetermined value.
[0050]
in this case Since the motor drive by the phase difference control during the normal operation can be realized without changing the method of detecting the phase difference information, the operation method is switched from the conventional synchronous operation at the start-up to the normal back-up operation. Is no longer needed. Therefore, a smooth transition from startup to normal operation can be realized, and torque fluctuation, noise and vibration can be reduced, and motor stoppage due to poor switching can be avoided. Further, since there is no need to switch the phase difference information detection method, the load on the control system can be reduced, and the cost can be reduced.
[0051]
Also preferably , The control means By the judgment means Synchronous motor But Stable startup completed Is determined to be After that, the synchronous motor is driven by increasing the rotational speed of the synchronous motor to a rotational speed at which the back electromotive voltage in the coil can be detected, and performing energization switching based on the back electromotive voltage.
[0052]
in this case The motor can be driven based on the back electromotive voltage at the time of starting and the motor driving based on the back electromotive voltage at the time of normal operation. Thus, a control system can be realized.
[0053]
Also preferably The control means drives the synchronous motor by 180 ° at least when the synchronous motor is started.
[0054]
in this case At the time of startup, there is no need to detect the back electromotive voltage by providing an energization suspension period in the motor drive waveform such as 120 ° square wave energization, etc., which can reduce torque fluctuations, noise, vibration, etc., and realize a smooth startup Is done. Further, since the magnetic flux of the magnet can be used effectively, high efficiency can be realized.
[0055]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the same or corresponding portions have the same reference characters allotted, and description thereof will not be repeated.
[0056]
A motor start control device according to an embodiment of the present invention will be described with reference to FIG. The motor start control device shown in FIG. 1 includes a motor coil of a plurality of phases (three phases) for a stator, an inverter unit 2 for driving a synchronous motor 1 having a permanent magnet for a rotor, an AC power supply 4, and an AC power supply 4 for DC. The AD / DC converter circuit 3 that converts and supplies DC power to the inverter unit 2 flows into a specific phase (the U phase in FIG. 1) among the motor coil terminals U, V, and W of the synchronous motor 1. It includes a current sensor 5 for detecting a motor current a, a motor current detection amplifier 6, and a control unit 7.
[0057]
The motor current detection amplifier 6 amplifies the motor current a detected by the current sensor 5 by a predetermined amount and adds an offset so that the motor current a falls within a voltage range that can be taken in by an A / D converter (not shown) included in the control unit 7. The current signal b is output.
[0058]
The control unit 7 includes a phase difference detection unit 8 that detects information (phase difference information) relating to a phase difference between the motor drive voltage and the motor current signal b output from a sine wave data creation unit 14 described below, and a target phase difference. A target phase difference information storage unit 9 for storing information (target phase difference information); an adder 10 for calculating error data between the target phase difference information and the detected phase difference information; a proportional error with respect to the calculated error data It includes a PI calculation unit 11 that calculates data and integrated error data and outputs a duty reference value of a PWM duty in a normal operation, and a rotation speed setting unit 12 that sets a rotation speed command of the synchronous motor 1.
[0059]
The rotation speed setting unit 12 is controlled by a start control unit 16 described later when the motor is started, and is controlled by a preset value or an external command during normal operation.
[0060]
The control unit 7 further converts the sine wave data table 13 for each phase of the motor coil terminals U, V, and W from the sine wave data table 13 in accordance with the rotation speed command and the time lapse in the rotation speed setting unit 12 for storing the sine wave data. A sine wave data generator 14 for reading out the corresponding sine wave data and outputting a U-phase motor drive voltage based on the U-phase sine wave data as a specific phase, and a sine wave output from the sine wave data generator 14 Based on the data and a duty reference value received via a switch 17 described later, a PWM generation / output unit 15 for each phase outputs a PWM waveform to each drive element of the inverter unit 2, and the synchronous motor 1 is started stably. Control unit 16 for starting the motor, a start control (start control unit 16) used at the time of starting the motor, and a PI control (PI calculation unit 11) used at the time of the normal operation. Including the changing switch 17.
[0061]
The start control unit 16 detects a stable start and outputs a command to prohibit a change in the rotation speed in the rotation speed setting unit 12 or a command to forcibly change the rotation speed based on the detection result. The activation control unit 16 further has a function of controlling the switch 17 so that the PI control cannot be performed during the activation control. Therefore, the switch 17 inputs the duty reference value from the start control unit 16 when the motor is started and the duty reference value output from the PI calculation unit 11 to the PWM generation / phase distribution unit 15 during normal operation.
[0062]
The control unit 7 is configured by a microcomputer. At this time, the processing in each of the units 8 to 17 is performed by software. However, the present invention is not limited to this, and the units 8 to 17 may be configured in hardware so as to perform the same processing.
[0063]
Note that examples of the current sensor 5 include a so-called current sensor including a coil element and a Hall element, and a current transformer. In the embodiment of the present invention, the motor current is detected only for a specific phase among a plurality of phases. However, the present invention is not limited to this, and the motor current for each phase may be detected. In this case, it is possible to perform a more accurate stable start.
[0064]
The sine wave data may not be created based on the sine wave data table 13 stored in advance, but may be created by calculation. Further, the drive waveform is not limited to a sine wave.
[0065]
The operation of the motor start control device shown in FIG. 1 will be briefly described. During start-up of the synchronous motor 1, the start-up control unit 16 performs the rotation speed setting control or the creation of the duty reference value. The switch 17 turns on the activation side (the side connected to the output node of the activation control unit 16). When switching between the phase difference information detection method during start-up control and the phase difference information detection method during normal operation, a start-up phase difference detection command is output from the start-up control unit 16 to the phase difference detection unit 8. Is done.
[0066]
When the start control unit 16 detects that the synchronous motor 1 has started to rotate stably and the start has been completed, the start control unit 16 prohibits the rotation speed setting command and the switch 17. Is The normal side (the side connected to the output of the PI calculation unit 11) is turned on. Thereby, the creation of the duty reference value by the PI calculation unit 11 is permitted.
[0067]
The PI calculation unit 11 is feedback-controlled so that the phase difference between the motor drive voltage and the motor current is constant, thereby enabling the synchronous motor 1 to rotate with a desired phase difference during normal operation. .
[0068]
At this time, the sine wave data creation unit 14 controls the motor rotation speed based on the rotation speed setting unit 12 and the information stored in the sine wave data table 13, and an appropriate sine wave data is selected and created each time. You. As a result, a desired rotating magnetic field is output. The PWM generation / phase distribution unit 15 outputs a PWM signal corresponding to each drive element from the sine wave data and the duty reference value. Therefore, the rotation frequency of the synchronous motor 1 and the rotating magnetic field generated by the conduction are synchronized. That is, synchronous operation is realized.
[0069]
As described above, according to the above-described configuration, it is not necessary to detect the back electromotive voltage of the synchronous motor 1 and it is not necessary to provide an energization suspension period during the energization of the synchronous motor 1, so that efficient motor driving is realized. You.
[0070]
During normal operation, the synchronous motor 1 is driven based on the detected phase difference as in the case of starting the motor. That is, the same phase difference information as during motor startup is used in normal times. As a result, there is no need to shift from synchronous operation during startup, which has been performed conventionally, to counter-electromotive operation. Therefore, the processing is simplified, and the transition from startup to normal operation can be performed smoothly. Accordingly, torque fluctuation and speed fluctuation at the time of switching are eliminated. Therefore, highly accurate motor driving is realized.
[0071]
During normal operation, 120-degree rectangular wave driving may be performed. An example of the configuration in this case will be described with reference to FIG. The control unit 7 shown in FIG. 2 includes switches 17a and 17b. The switches 17a and 17b are switches for switching between the start of the motor and the normal operation, similarly to the switch 17.
[0072]
The activation control unit 16 has a function of controlling the switches 17a and 17b so that the PI control cannot be performed during the activation control. By the switch 17a, the output of the start control unit 16 is input to the PWM generation / phase distribution unit 15 when the motor is started and the output of the PI calculation unit 11 is input to the PWM distribution unit 15 during the normal operation. By the switch 17b, the sine wave data output from the sine wave data generator 14 when the motor is started, and the energization switching signal output from the position detector 18 during normal operation are input to the PWM generator / phase distribution unit 15.
[0073]
The position detecting unit 18 shown in FIG. 2 detects the position of the motor rotor from the back electromotive force during the power supply suspension period in each of the phases U, V, and W. The position detection unit 18 outputs an energization switching signal (pulse corresponding to the rotation position of the motor) and speed information (information corresponding to the rotation speed of the motor) as detection results.
[0074]
The adder 10 illustrated in FIG. 2 includes target speed information output from a target speed information storage unit 19 that stores a target motor rotation speed (target speed information) and speed information output from a position detection unit 18. , And outputs the calculation result to the PI calculation unit 11. The PI operation unit 11 is controlled based on the error data.
[0075]
During normal operation, feedback control is performed in which the energization state is switched in accordance with the energization switching signal output from the position detection unit 18 and the duty reference value is set so that the speed information approaches the target speed information. Thus, the synchronous motor 1 is driven so as to achieve the target speed. At this time, since the energization is switched according to the back electromotive force signal, the drive system can be configured very easily.
[0076]
Note that, after setting the rotation speed so that the back electromotive voltage can be accurately detected, switching to the normal operation realizes more reliable switching of the state.
[0077]
As described above, the present invention does not depend on the energization method during the normal operation, and can be applied to any energization method. In addition, the conduction waveform during the start-up control is a sine wave. This is because the motor current flows smoothly to the motor coil, a rotating magnetic field with little ripple is generated, and the effect of smoothly starting the motor rotation is exerted. . However, the present invention is not limited to this, and the object of the present invention is achieved with any conduction waveform.
[0078]
For reference, FIG. 3 shows a drive voltage waveform of each phase in the 180-degree sine wave energization as an example of a drive waveform having no energization suspension period, and a 120-degree rectangular shape as an example of a drive waveform having an energization suspension period. FIG. 4 shows the drive voltage waveforms of the respective phases in the wave energization. 3 and 4, the vertical axis corresponds to voltage and the horizontal axis corresponds to time.
[0079]
As shown in FIG. 3, in 180-degree sine wave energization, the voltage of each phase U, V, and W has a sine waveform. On the other hand, in the 120-degree rectangular wave energization shown in FIG. 4, the phases U, V, and W are energized by the rectangular wave during the 120-degree period, and are energization suspension periods during the 60-degree period.
[0080]
Next, the operations of the phase difference detection unit 8 and the activation control unit 16 according to the embodiment of the present invention will be described with reference to FIGS.
[0081]
5 to 7 are timing charts showing the relationship between the motor drive voltage waveform and the motor current signal waveform. Note that the actual motor drive voltage waveform is a PWM type waveform, and only the phase information of the motor drive voltage is input to the phase difference detection unit 8, but the motor drive voltage waveform is used instead of the phase information for explanation. Will be explained. Note that the symbols θA, θB1, θB2, θB3, and θC in the figure represent phase differences.
[0082]
FIG. 5 shows a state where the duty reference value is very small with respect to the energizing frequency to the motor coil terminals, that is, the generated rotating magnetic field frequency and the load torque, and the synchronous motor 1 does not rotate nor vibrate (state A). It corresponds to.
[0083]
FIG. 6 shows that the duty reference value is small with respect to the energizing frequency to the motor coil terminals, that is, the generated rotating magnetic field frequency and the load torque, and the synchronous motor 1 does not rotate normally and vibrates or loses synchronism. This corresponds to the state (state B).
[0084]
FIG. 7 shows that the duty reference value is set to an appropriate value with respect to the energizing frequency to the motor coil terminal, that is, the rotating magnetic field frequency and the load torque being generated, and the synchronous motor 1 is rotating normally. This corresponds to the state (state C).
[0085]
Referring to FIGS. 5 to 7, in state A where synchronous motor 1 is not rotating at all and state C where synchronous motor 1 is rotating normally, the phase difference between motor drive voltage and motor current signal b is It is constant (θA, θC) and stable.
[0086]
On the other hand, in the state B in which the synchronous motor 1 is vibrating or out of synchronization, the phase difference between the motor drive voltage and the motor current signal b is not constant and fluctuates (θB1, θB2, θB3,...). .
[0087]
In the state A, since the synchronous motor 1 is not moving at all, the motor current when the motor drive voltage is directly applied to the coil is detected, so that the phase difference θA is stable. In state B, since the PWM duty (motor drive voltage) is small, a torque that can overcome the motor load cannot be generated, and the synchronous motor 1 vibrates. Since the back electromotive voltage fluctuates due to the vibration or step-out of the synchronous motor 1, the motor current flowing according to the difference voltage between the motor drive voltage and the back electromotive voltage vibrates, and the phase differences θB1, θB2, and θB3 change in amplitude. Or it swings in phase. That is, the motor rotor is not energized with the same positional relationship. In the state C, the startup is performed normally, the synchronous motor 1 is rotating normally and normally, and the back electromotive voltage waveform and the rotating magnetic field waveform are synchronized. Therefore, the motor current signal b flows in synchronization with the motor drive voltage, so that the phase difference θC is stabilized.
[0088]
FIGS. 8 and 9 are diagrams for explaining the state of the synchronous motor 1 when the motor drive voltage or the energizing frequency is changed. In addition, each of the states A, B, and C in FIGS. 8 and 9 corresponds to the states A, B, and C in FIGS.
[0089]
FIG. 8 shows the correspondence between the state of the motor and the phase difference when the energizing frequency for generating the rotating magnetic field is fixed and the duty reference value is increased with time. In order to keep the energization frequency constant, the start control unit 16 outputs a rotation speed change prohibition command to the rotation speed setting unit 12 shown in FIG. As the duty reference value increases, the state of the motor changes to states A, B, and C.
[0090]
FIG. 9 shows the correspondence between the state of the synchronous motor 1 and the phase difference when the duty reference value is fixed and the energizing frequency is reduced with time. In order to gradually lower the energizing frequency, a command to reduce the rotational speed is output from the activation control unit 16 to the rotational speed setting unit 12 shown in FIG. As the energizing frequency is lowered, the state of the motor changes to states A, B and C.
[0091]
The conventional motor start control device does not include a mechanism for detecting the stable rotation state in the state C. For this reason, the start-up has been completed at the time of the state A or B before reaching the state C, and switching to the normal operation mode based on the back electromotive voltage reference or the like has caused the start-up failure.
[0092]
By the way, in the state B, as shown in FIG. 6, the phase difference information fluctuates every time and is detected. U In some cases, or when a back electromotive voltage is used, the back electromotive voltage is also detected by fluctuating with the vibration of the synchronous motor. Therefore, the phase difference information or the back electromotive voltage at the time of vibration in state B may be detected as if the synchronous motor is rotating stably depending on the state of vibration. Further, information in the opposite direction may be detected at the time of detection before and after due to vibration. That is, erroneous detection is induced. Therefore, if the motor drive by the phase difference control or the motor drive by the back electromotive voltage detection is performed in the state B, not only cannot the synchronous motor be driven stably but also the synchronous motor loses synchronism.
[0093]
Therefore, in order to realize stable startup, it is necessary to accurately detect stable rotation (state C), that is, to detect that the phase difference between the motor drive voltage and the motor current signal has reached state C in FIG. There is a need.
[0094]
Therefore, the motor start control device according to the present invention detects completion of the start by detecting that the stable phase difference shown in FIG. 7 has been obtained a predetermined number of times. Thereby, stable startup is realized. For this reason, the activation control unit 16 according to the embodiment of the present invention calculates an average value by averaging the phase difference information of a predetermined number of times, and the variation of each phase difference information with respect to this average value is within a predetermined range. It is determined whether or not the state C belongs by determining whether or not the state C exists.
[0095]
What is important here is that the driving voltage is controlled by the phase difference information itself because there is a state B in which the phase difference oscillates because the synchronous motor 1 is vibrating or out of synchronization during the start-up process as described above. A stable start cannot be realized by control using phase difference information itself, such as judging a start state or performing a phase difference control which is an effective control method during normal operation. Therefore, at the time of startup, it is detected whether the fluctuation of the phase difference is large or small (that is, whether the variation of the phase difference information is large or small), and based on the detection result, the motor state at startup is determined and the startup control is performed. It is necessary.
[0096]
By the way, according to FIGS. 5 to 7 and FIGS. 8 to 9, the phase difference is stably detected in each of the states A and C. Therefore, it is necessary to surely detect the state C when the activation is completed.
[0097]
For this reason, as one method of the embodiment of the present invention, a fixed rotation frequency and a fixed duty reference value are used, and these fixed values are set to values for the motor state to be in the stable rotation of the state C. . Then, the start of stable rotation is detected, and a stable start state is detected.
[0098]
Alternatively, as another method, the transition from the state B to the state C is detected by changing the energizing frequency or the duty reference value. When changing the duty reference value, the duty reference value set at the beginning of startup is set to a value lower than the duty reference value in the state C in which the motor rotates stably (within the range of the initial duty reference value shown in FIG. 8). After the start-up, while gradually increasing the duty reference value, it is first detected that each phase difference varies (that is, state B), and then it is determined that each phase difference has stabilized (that is, state C). To detect. As a result, stable startup is reliably detected.
[0099]
Note that the initial value of the duty reference value is a duty value that generates a torque lower than the load torque with respect to a possible load torque at the time of starting the motor.
[0100]
If the rotational speed command (rotating magnetic field frequency) or the initial rotating magnetic field frequency to be fixed is too high, the vibration or step-out of the motor in the state B becomes large, There is a possibility of rotating. Therefore, depending on the synchronous motor to be used, a low speed of about 500 rpm or less is appropriate.
[0101]
The process of the startup control unit 16 when detecting a stable startup while changing the duty reference value will be described with reference to FIG. Referring to FIG. 10, in step S1, if there is a motor start command, the rotational speed command is fixed to a predetermined value, the duty reference value is initialized, switch 17 is selected on the start side, and each variable is set. initialize. The initial value of the duty reference value is set to a low value such that the synchronous motor 1 does not rapidly and stably rotate. If the duty reference value is not changed in the following operation, the duty reference value is set to a value such that the synchronous motor 1 enters the state C described above.
[0102]
In step S2, it is determined whether or not the phase difference detection unit 8 has detected the phase difference information. If not, the process proceeds to step S21, and the loop processing is repeated until new phase difference information is detected.
[0103]
In step S3, when the phase difference information is detected, the detected phase difference information is stored in the array P (n). In the following step S4, the number n of phase difference information detections is updated (n = n + 1). In step S5, it is determined whether or not the number n of phase difference information detections is equal to or greater than a predetermined number. If the number is less than the predetermined number, the process proceeds to step S21, and the loop processing is repeated toward detection of new phase difference information. If the phase difference information detection number n is equal to or more than the predetermined number in step S5, the process proceeds to step S6, and the phase difference information detected for the predetermined number of times is averaged.
[0104]
In the following step S7, it is determined whether the state of the synchronous motor 1 is the state A or the state B. It is assumed that the initial state of the synchronous motor 1 is the state A, and the current state is determined by the following processing. If the current state of the synchronous motor 1 is the state A, the process proceeds to step S8 (（S13), and if the current state is the state B, the process proceeds to step S14 (〜S19).
[0105]
Steps S <b> 8 to S <b> 13 are processes for determining whether or not the current synchronous motor 1 is in the state A and has shifted to the state B. Specifically, in step S8, it is determined whether or not the variation of each phase difference information is larger than a certain range with respect to the averaged phase difference information. If the variation is large (that is, the phase difference fluctuates), the variable m is updated in step S9. If the variation is small (the change in the phase difference is small), the variable m is reset to 0 in step S13, and the process proceeds to step S20.
[0106]
After updating the variable m in step S9, it is determined in step S10 whether the variable m has reached a predetermined number of times. That is, it is determined based on the value of the variable m whether or not the state in which the variation is large has continued for a predetermined number of times. As a result, it is possible to reliably detect a change in the phase difference.
[0107]
If the variable m has reached the predetermined number, the variable m is reset in step S11. Then, in step S12, the fact that the current synchronous motor 1 is in state B is stored, and the process proceeds to step S20. In step S20, the variable n is reset for averaging the next phase difference information.
[0108]
If it is determined that the synchronous motor 1 is in the state B at present, the processing of steps S14 to S19 is performed instead of steps S8 to S13. More specifically, in step S14, it is determined whether or not the variation of each phase difference information is smaller than a certain range with respect to the averaged phase difference information. If the variation is small (that is, the phase difference is stable), the variable m is updated in step S15. If the variation is large, the variable m is reset to 0 in step S19, and the process proceeds to step S20.
[0109]
After updating the variable m in step S15, it is determined in step S16 whether the variable m has reached a predetermined number of times. That is, it is determined based on the value of the variable m whether or not the state in which the variation is small has continued for a predetermined number of times. As a result, a stable state of the phase difference is reliably detected.
[0110]
If the variable m has exceeded the predetermined number, the variable m is reset in step S17. Then, it is determined that the synchronous motor 1 has entered the state C in which the synchronous motor 1 is rotating stably, and in step S18, the rotation speed fixing command is released, the switch 17 is set to the normal side, and the startup processing is completed.
[0111]
As described above, in step S20, the variable n is reset, and in subsequent step S21, a process of adding a predetermined addition value to the duty reference value, outputting PWM, and gradually increasing the motor drive voltage is performed. Further, when the duty reference value becomes larger than the limit value, the start stop command, the restart command or the addition of the duty reference value is prohibited. This is to prevent an overcurrent from flowing into the inverter and the synchronous motor 1 due to an increase in the duty reference value, thereby preventing the inverter and the synchronous motor 1 from being damaged.
[0112]
The process in step S21 is not performed when the duty reference value is fixed. The above loop processing from step S2 to S21 is repeated until activation is completed.
[0113]
As an example of a method of setting a reference value for detecting a variation in the phase difference information, a variation when the synchronous motor 1 is rotating stably without vibration or step-out is detected and determined based on the variation. I do. However, the value is set so that the synchronous motor 1 does not stop when switching to the normal operation.
[0114]
As described above, the motor startup control device according to the embodiment of the present invention can reliably detect the completion of stable startup by utilizing the fact that the phase difference information has little variation during stable rotation. In addition, since the state of the synchronous motor 1 is sequentially detected, a stable start is realized without starting failure.
[0115]
Further, the motor drive voltage (PWM duty) applied to the synchronous motor 1 in the initial stage of the start is set to a low voltage value (duty) such that the synchronous motor 1 does not rotate rapidly and stably, and then the voltage is gradually increased. Go. Further, the vibration or step-out (state B) of the synchronous motor 1 is detected based on a large variation in the phase difference, and thereafter, the stable rotation (state C) of the synchronous motor 1 is detected based on a small variation in the phase difference. The phase difference stable state (state A) when the synchronous motor 1 does not rotate at all (state A) and the state C are surely distinguished.
[0116]
As a result, even if a position detector is not added to the synchronous motor 1, stable and reliable starting without failure can be determined and executed. Further, since it is not necessary to detect the back electromotive voltage, it is not necessary to make the conduction waveform including a conduction suspension period such as a 120 ° rectangular wave conduction, and the waveform is largely generated at a low speed such as a startup at a small rotation speed. Torque fluctuation can be suppressed. In addition, a smooth rotation can be realized by using a drive waveform such as 180 ° sine wave energization, and the motor magnet magnetic flux can be effectively used since the energization suspension period is not included, so that highly efficient motor drive is realized.
[0117]
Note that, even when the energizing frequency is changed as shown in FIG. 9, the initial value is set to a value that does not enter the state C, and the start-up is performed while changing it in the same procedure as the processing shown in FIG. By judging the completion, stable and reliable start detection is realized.
[0118]
FIG. 8 shows a case where the duty reference value (motor drive voltage) is increased linearly. For example, the duty reference value is kept constant while the variation of the phase difference is checked, It is also possible to increase the value. In this case, the process of step S21 shown in FIG. 10 is performed immediately before step S20. When the duty reference value is increased stepwise as described above, it is possible to cope with a change in the phase difference due to a change in the duty reference value while checking the variation in the phase difference.
[0119]
Next, an example of setting a duty reference value for performing stable and high-speed startup completion will be described with reference to FIG. FIG. 11 is a timing chart illustrating an example of a method of changing the duty reference value according to the embodiment of the present invention. Each of states A, B, and C shown in FIG. 11 corresponds to states A, B, and C in FIGS.
[0120]
In the embodiment of the present invention, as shown in FIG. 11, the added value of the duty reference value is changed according to the states A, B, and C of the synchronous motor, or the magnitude of the variation of the phase difference.
[0121]
When the synchronous motor 1 is in the state A (a state in which the phase difference is small immediately after startup), it is necessary to greatly change the duty reference value until a state C indicating stable rotation. Therefore, a large added value is taken.
[0122]
In the state B of the synchronous motor 1 (a state in which the phase difference is large and the synchronous motor 1 is vibrating or out of synchronization), the addition value is set according to the magnitude of the variation of the phase difference. That is, in a state where the variation of the phase difference is very large, it is often immediately after the shift to the state B where a lot of vibration or step-out occurs, and thus the addition value is set to be large at this time. In the state B, when the variation in the phase difference is small, the vibration or the step-out is reduced, and the state is often immediately before the transition to the state C. Therefore, in this case, the addition value is set small. That is, in the state B, the addition value is set according to the variation amount of the phase difference.
[0123]
As described above, by changing the duty reference value (or the energizing frequency) according to the variation of the phase difference information or the state of the synchronous motor, the state quickly shifts to the state C, which is a stable rotation state, and the time until the start is completed is reduced. can do. Furthermore, vibration in state B is not desirable for a device connected to a motor bearing or a synchronous motor. However, by setting the amount of change according to the variation of the phase difference as described above, the state B with a lot of vibration or step-out can be quickly passed, and the life of the motor can be prolonged and the reliability of peripheral devices can be realized. .
[0124]
When the rotation frequency and the duty reference value are set to values at which the synchronous motor 1 is in the stable state C, the synchronous motor 1 vibrates immediately after the start because the energized position is indefinite. In the processing shown in FIG. 10, this is determined as state B. However, since the energized position thereafter starts stable and stable rotation, it is possible to reliably detect the completion of stable startup by detecting this stable rotation state.
[0125]
The phase difference information can be detected by detecting the phase of the motor current signal with respect to the reference phase of the motor drive voltage by detecting a zero-crossing edge or the like. However, if the detection method shown in FIGS. Can be realized. The actual motor drive voltage waveform is of a PWM type, and phase information of the motor drive voltage is input to the phase difference detection unit 8. However, in FIGS. It will be described using FIG.
[0126]
As an example of the phase difference detection method, as shown in FIG. 12, the motor current signal b in a predetermined phase period θ0 (0 to 180 ° in FIG. 12) of the motor drive voltage waveform is integrated to detect the area Is0. , And the area Is0 is used as phase difference information.
[0127]
As a method for obtaining the area Is0, as shown in FIG. 12, a predetermined number of times (FIG. In two Is a simple method of performing A / D sampling of s0 to s9 (total 10 times) and adding the results (Is0 = Σ (I0: I9)). Since the motor drive voltage gradually increases, the increase with respect to the phase difference average is very small. Therefore, the phase difference information can be obtained by calculating the area Is0.
[0128]
That is, a change in the area Is0 indicates a shift in the phase difference. Therefore, the above-described activation determination is performed by detecting whether or not the area Is0 varies. Since this method simply integrates the sampled motor current signal b, it can be realized with a simple circuit configuration or processing.
[0129]
As another example of the phase difference detection method, as shown in FIG. 13, A / D sampling is performed at two predetermined phase periods θ0 and θ1 of the motor drive voltage waveform (0 to 90 ° and 90 to 180 ° in FIG. 13). ) To detect the areas Is0 and Is1 of the motor current signal b (Is0 = Σ (I0: I4), Is1 = Σ (I5: 19)). Then, a ratio (Is0 / Is1) of the area values Is0, Is1 in each phase period θ0, θ1 is calculated, and this ratio is used as phase difference information.
[0130]
By using the area ratio, phase difference information can be accurately detected. Therefore, highly accurate detection of the phase difference information becomes possible. The start-up stability is determined by determining the variation of the phase difference information.
[0131]
Note that, as shown in FIGS. 12 and 13, by setting the current sampling interval of the motor current signal b to a constant interval z, the setting of the capture interval can be easily performed.
[0132]
As described above, according to the motor start control device according to the embodiment of the present invention, since the phase difference information is obtained from the area of the motor current signal, the noise and the motor current signal can be compared with the edge detection method such as zero cross detection. It is possible to detect accurate and accurate phase difference information that is strong against shakes and the like. Therefore, the stability of startup is further improved.
[0133]
During normal operation, the phase difference information obtained as described above is used when the motor is driven by the phase difference control in the configuration of FIG. 1 so that the phase difference information approaches the target phase difference information. Control can be performed. As a result, the transition from startup to normal operation can be performed more smoothly. That is, the same phase difference information is used for the start-up and the normal operation, and a process of checking a variation of the phase difference is performed at the time of the start-up, and a process of controlling the phase difference to a desired value is performed at the time of the normal operation.
[0134]
The embodiments disclosed this time are to be considered in all respects as illustrative 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.
[0135]
【The invention's effect】
As described above, according to the motor start control device of the present invention, the rotation state of the motor is detected according to the phase difference between the motor drive voltage and the motor current, and the start of the motor is determined. Therefore, the start-up can be reliably determined by a sensorless system without a motor position detector, and stable start-up without failure is realized. In addition, since the sensorless system is adopted, a position detector is not required and cost reduction is realized. Further, there is no need to provide an energization suspension period in the motor drive waveform as in the case of 120 ° rectangular wave energization, and it is not necessary to detect a back electromotive voltage. 180 ° sine wave energization can be performed, so that torque fluctuation, noise, vibration, etc. Can be reduced, and a smooth startup can be realized. Further, since the magnetic flux of the magnet can be used effectively, high efficiency can be realized.
[0136]
Further, according to the motor start control device of the present invention, the stable rotation state of the motor can be more reliably detected, so that failure to start the motor can be avoided, and the reliability of the start determination is further increased. That is, high reliability can be realized.
[0137]
Furthermore, according to the motor start control device according to the present invention, since the value of the PWM duty is limited, it is possible to prevent the current from being too large, causing an overcurrent to flow into the inverter or the motor and damaging them. . Therefore, the reliability of the device is improved.
[0138]
According to the motor start control device of the present invention, phase difference information is detected in accordance with the area of the motor current. It is possible to reliably detect the phase difference information without being affected by the fluctuation. Therefore, a malfunction is avoided and a stable start is realized.
[0139]
According to the motor start control device of the present invention, in addition to the above-described effects, the motor drive by the phase difference control during the normal operation can be realized without changing the method of detecting the phase difference information. It is not necessary to switch the operation method from the synchronized operation at the time of startup to the back-emergence operation at the normal time. Therefore, a smooth transition from startup to normal operation can be realized, and torque fluctuation, noise and vibration can be reduced, and motor stoppage due to poor switching can be avoided. Further, since there is no need to switch the phase difference information detection method, the load on the control system can be reduced, and the cost can be reduced.
[0140]
Further, according to the motor start control device of the present invention, the area of the motor current can be easily detected, so that the configuration of the control system can be simplified and the cost can be reduced.
[0141]
Further, according to the motor start control device of the present invention, the time until the start is completed can be shortened, so that the motor can be started up quickly and the control performance can be improved. Furthermore, since it is possible to quickly pass through the vibration or step-out state and shift to the stable rotation state, the life of the motor bearing or the motor device itself is prolonged, and high reliability can be realized.
[0142]
Further, according to the motor start control device according to the present invention, at the time of start, the motor drive by the phase difference, at the time of normal operation, the motor can be driven based on the back electromotive voltage, thereby realizing a reliable start, During normal operation, it is possible to realize a control system with a simple configuration by switching the energization by the back electromotive voltage.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an example of a configuration of a motor start control device according to an embodiment of the present invention.
FIG. 2 is a diagram illustrating an example of a configuration of a motor start control device according to an embodiment of the present invention.
FIG. 3 is a diagram showing a drive voltage waveform of each phase when a 180-degree sine wave is applied.
FIG. 4 is a diagram showing a drive voltage waveform of each phase when a 120-degree rectangular wave is applied.
FIG. 5 is a timing chart showing a relationship between a motor drive voltage waveform and a motor current signal waveform according to the embodiment of the present invention.
FIG. 6 is a timing chart showing a relationship between a motor drive voltage waveform and a motor current signal waveform according to the embodiment of the present invention.
FIG. 7 is a timing chart showing a relationship between a motor drive voltage waveform and a motor current signal waveform according to the embodiment of the present invention.
FIG. 8 is a diagram for explaining a state of the synchronous motor 1 when the motor drive voltage or the energizing frequency is changed according to the embodiment of the present invention.
FIG. 9 is a diagram for explaining a state of the synchronous motor 1 when the motor drive voltage or the energizing frequency is changed according to the embodiment of the present invention.
FIG. 10 is a flowchart illustrating a process of a startup control unit 16 when detecting a stable startup while changing a duty reference value.
FIG. 11 is a diagram for describing an example of setting of a duty reference value for performing stable and high-speed startup completion.
FIG. 12 is a diagram for describing an example of detection of phase difference information according to the embodiment of the present invention.
FIG. 13 is a diagram for describing an example of detection of phase difference information according to the embodiment of the present invention.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 synchronous motor, 2 inverter section, 3 AD / DC converter circuit, 4 AC power supply, 5 current sensor, 6 motor current detection amplifier, 7 control section, 8 phase difference detection section, 9 target phase difference information storage section, 10 adder , 11 PI calculation unit, 12 rotation speed setting unit, 13 sine wave data table, 14 sine wave data creation unit, 15 PWM creation / each phase distribution unit, 16 start control unit, 17, 17a, 17b switch, 18 position detection unit, 19 Target speed information storage unit.

Claims (19)

A motor start control device for controlling a synchronous motor,
Motor current detection means for detecting a motor current flowing through the coil of the synchronous motor,
Phase difference detection means for detecting phase difference information between the motor current and the drive voltage supplied to the coil,
Determining means for determining whether or not the synchronous motor is in a stable start completion state, based on a variation in the phase difference information ;
A motor start control device, comprising: control means for controlling the drive voltage applied to the terminal of the coil and the energizing frequency to the terminal of the coil based on a result of the determination by the determination means . The phase difference information,
The motor start control device according to claim 1, wherein the motor start control device is an area of the motor current waveform during a predetermined phase period of the drive voltage waveform. The phase difference information,
The ratio of a first area of the motor current waveform during a first predetermined phase period of the drive voltage waveform to a second area of the motor current waveform during a second predetermined phase period of the drive voltage waveform. Motor start control device. The area is
3. The motor start control device according to claim 2, wherein a value obtained by performing A / D sampling of the motor current at a predetermined interval during the predetermined phase period is integrated. The first area is
A value obtained by A / D sampling the motor current at predetermined intervals during the first predetermined phase period;
The second area is
4. The motor start control device according to claim 3, wherein a value obtained by A / D sampling the motor current at predetermined intervals during the second predetermined phase period is integrated. 5. The determining means includes:
Based on the variation of the phase difference information, the synchronous motor is equal to or unstable rotation state, in response to determining that the unstable rotation state, based on the variation of the phase difference information, the synchronous motor is determined whether the stable activation completion state, the motor start control device according to any one of claims 1 to 5. The determining means includes:
By comparing the variation with a predetermined value of the phase difference information, the synchronous motor is determined whether the stable activation completion state, the motor start control device according to claim 1. The determining means includes:
By comparing the variation of the phase difference information with a first predetermined value, it is determined whether or not the synchronous motor is in an unstable rotation state , and by comparing the variation of the phase difference information with a second predetermined value, synchronous motor is determined whether the stable activation completion state, the motor start control device according to claim 6. The control means,
Up to the stable activation completion state from the synchronous motor activation start, the current frequency is the predetermined value, the causes the duty reference value of the drive voltage is time-varying, motor starting according to any one of claims 1 to 8 Control device. The control means,
The synchronous motor of the activation start up to the stable activation completion state, the drive voltage to a predetermined value, the cause energization frequency temporally changed, the motor start control device according to any one of claims 1 to 8. The control means,
Wherein the synchronous motor activation start up to the stable activation completion state, each of the current frequency and the driving voltage is set to a value in the stable startup of the synchronous motor, according to any one of claims 1 to 8 Motor start control device. The control means,
10. The motor start control device according to claim 9 , wherein when starting the synchronous motor, an amount of change in a duty reference value of the drive voltage is set according to a variation in the phase difference information. The control means,
The motor start control device according to claim 9 , wherein when starting the synchronous motor, a change amount of a duty reference value of the drive voltage is set according to a state of the synchronous motor. The control means,
With the limit value for the duty reference value of the drive voltage, the motor start control device according to claim 1 2 or 1 3. The control means,
At the time of startup of the synchronous motor, according to the variation of the phase difference information, it sets the change amount of the current frequency, the motor start control device according to claim 1 0. The control means,
At the time of startup of the synchronous motor, the synchronous according to the state of the motor, sets the change amount of the current frequency, the motor start control device according to claim 1 0. The control means,
After the synchronous motor is determined to be stable activation completion state by said determining means, said phase difference information to drive the synchronous motor to a predetermined value, according to any one of claims 1 to 1 6 Motor start control device. The control means,
After the synchronous motor is determined to be stable activation completion state by said determining means increases the rotational speed of the synchronous motor until the rotational speed is possible counter electromotive voltage detected in the coil, based on the counter electromotive voltage The motor start control device according to any one of claims 1 to 17 , wherein the synchronous motor is driven by performing energization switching. The control means,
At least in the synchronous motor starts, the synchronous motor, 180 ° energized drive, motor start control device according to any one of claims 1 to 1 8.

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