JP2000201494A - Motor driving device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To drive a motor with a sine wave current without using any magnetic pole position sensor and, at the same time, to smoothly start the motor. SOLUTION: A motor driving device is provided with a magnetic pole position detecting means 38 that outputs a signal indicating the position of a rotor based on the voltage difference between the neutral points of a Y-connected resistance circuit 36 and a motor 30, an inverter 32 that supplies driving signals to the motor 30, and an inverter control means 40 that converts the driving signals into sine wave signals which change in the phase corresponding to that of the rotor. The control means 40 makes synchronous operation by advancing the conducting phase of the driving signals by a prescribed amount as compared with a reference phase, until the number of revolutions of the motor 30 exceeds a second prescribed value after the motor 30 is started and the number of revolutions reaches a first prescribed value. When the number of revolutions of the motor 3 exceeds the second prescribed number, the conducting phase of the driving signals is returned to the reference phase.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor driving apparatus for driving a motor without using an element for detecting a magnetic pole position of the motor, and more particularly to driving a motor with a sine wave current without using a magnetic pole position sensor. To a method for a motor drive device.

[0002]

2. Description of the Related Art FIG. 17 shows a DC brushless motor driving device disclosed in Japanese Patent Application Laid-Open No. 9-238493. 17, reference numeral 10 denotes a DC brushless motor 11
Is a rotor, 12 is a stator, 14 is a three-phase Y-connected resistance circuit, 16 is a rotational position detector, 18 is a microcomputer (hereinafter referred to as a “microcomputer”), 20 is a base drive circuit, and 22 is a level. The detector 24 is an inverter for operating the DC brushless motor.

The operation of the driving device shown in FIG. 17 will be described below. The DC brushless motor 10 includes a Y-connected stator 12. The neutral point potential of the stator 12 is
It is grounded to a GND potential equal to the reference potential of the rotational position detector 16. The neutral point output of the Y-connected resistor circuit 14 is input to an amplifier 26 included in the rotational position detector 16. The amplifier 26 obtains a potential difference signal between the neutral point of the stator 12 and the neutral point of the resistance circuit 14 based on the difference between the reference potential (GND potential) and the input signal. The rotation position detector 16 is
A position signal is generated based on the potential difference signal, and the position signal is input to the microcomputer 18.

[0004] The rotational position detector 16 has an integrator 28 for integrating the potential difference signal output from the amplifier 26. The output signal of the integrator 28 is input to the level detector 22. The level detector generates a signal indicating the level of the potential difference signal between the neutral points described above, and outputs the signal to the microcomputer 18.
Output to When the level of the potential difference signal is higher than a threshold value (smooth level of the PWM signal) generated inside the level detector 22, the microcomputer 18 changes the phase of the output voltage of the inverter 24 to reduce the level. Correct in the delay direction. On the other hand, when the level of the potential difference signal is smaller than the threshold value (smooth level of the PWM signal), the inverter 24 is increased to increase the level of the potential difference signal.
Is corrected in the leading direction.

[0005] The motor driving device shown in FIG. 17 is provided with the level detector 22 as described above, and controls the potential difference level between the neutral point of the stator 12 and the resistance circuit 14 to an appropriate level, thereby obtaining a DC drive. This controls the brushless motor to perform the maximum efficiency operation.

[0006]

Problems to be Solved by the Invention Japanese Patent Application Laid-Open No. 9-23849
In the motor drive device disclosed in Japanese Patent Publication No. 3 (1993) -1991, a potential difference signal between neutral points detected by the rotational position detector 16 is a third harmonic of an induced voltage generated in a coil of the stator 12 by rotation of the motor 10. Wave components, ie
This signal is caused by a harmonic component generated at a frequency three times the electric rotation angle of the motor 10. In the conventional motor driving device, the rotational position of the motor 10 is detected using the third harmonic component.

The DC brushless motor 10 is a synchronous machine that enables stable and efficient operation by synchronizing the rotation phase of the motor and the phase of a drive signal. Such a driving device for the motor 10 is required to bring the motor 10 into the synchronous operation after the motor 10 is started. In order to bring the motor 10 into synchronous operation, it is necessary to accurately detect the rotational position of the motor 10. According to the method of detecting the rotation position using the induced voltage of the motor 10, accurate position detection can be performed without any problem during the steady rotation of the motor 10.

However, the induced voltage of the motor 10 is
It has a characteristic that increases in proportion to the rotation speed of the motor 10. For this reason, the induced voltage has an extremely small value until the number of revolutions of the motor 10 is sufficiently increased after the motor 10 is started. Therefore, during that time, the potential difference signal level between the neutral point of the stator 12 and the resistance circuit 14 also has a very small value. Therefore, the technology disclosed in Japanese Patent Application Laid-Open No. 9-238493 cannot be applied to control at the time of starting the motor 10.

In recent years, a motor having an embedded magnet type rotor has been developed and commercialized. In a magnet-built-in type DC brushless motor, when the phase of a drive signal supplied from an inverter is advanced, distortion occurs in the induced voltage of the motor, and the harmonic component of the induced voltage increases. Since the potential difference signal between the neutral points uses the third harmonic component, when the phase is corrected in the leading direction, 3
The second harmonic increases, and as a result, the level of the potential difference signal increases. Conversely, when the phase of the drive signal supplied to the motor is corrected in the delay direction, the level of the potential difference signal decreases.

For this reason, when driving a magnet-embedded motor, if the phase of the drive signal is corrected in a direction that advances at all, the level of the potential difference signal increases significantly, while the phase of the drive signal is corrected in the direction that is slightly delayed. Then, the level of the potential difference signal is greatly reduced. Therefore, when driving the magnet-embedded motor, very complicated and delicate control is required to adjust the phase of the drive signal.

[0011] Further, in a 120-degree conduction method, which is a generally well-known DC brushless motor driving method,
A driving method is used in which a driving signal corresponding to an electrical angle having a pulse width of 120 degrees is stepwise supplied from an inverter to each phase of a motor. In the case of the 120-degree energization method, the phase of the output voltage of the inverter has a large phase margin, and the motor does not lose synchronism even if the energization phase slightly deviates from the optimal phase.

By the way, in order to suppress the pulsation of the torque of the DC brushless motor and reduce the noise level of the motor, the 180-degree energizing method (driving with a pulse width of 180 degrees for each phase) is required as compared with the 120-degree energizing method. It is generally known that the method of supplying a signal is excellent. However, the phase margin that can be secured by the 180-degree conduction method is 120
It is narrower than the phase tolerance that can be secured by the power distribution method.
Here, in the driving device disclosed in Japanese Patent Application Laid-Open No. 9-238493, a 180-degree energization method is applied. In the case of applying this method, the level detection of the potential difference signal between the neutral points is performed based on the rotation speed and load. If you do not change it stepwise according to the amount,
If the motor cannot be driven at the highest efficiency, and if the above is realized by a circuit, highly accurate level detection is required, resulting in an increase in the cost of the device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and a noise caused by torque pulsation of a motor is provided by driving an inverter so that a drive signal supplied to the motor has a sine wave shape. And achieves excellent quietness and smooth transition from motor start-up to steady-state rotation.Furthermore, the motor can be operated with the highest efficiency after the transition to steady-state rotation. An object of the present invention is to provide a DC brushless motor driving device.

[0014]

According to the first aspect of the present invention,
A motor drive device for driving a motor having a stator having a plurality of Y-connected armature windings and a rotor forming a plurality of poles with permanent magnets, wherein the motor driving device is in parallel with each of the armature windings. A resistor circuit having a plurality of resistors Y-connected so as to be connected to a first neutral point formed at the connection center of the plurality of resistors; and a connection center of the plurality of armature windings Magnetic pole position detecting means for outputting a position signal corresponding to the magnetic pole position of the rotor based on a voltage difference from a second neutral point formed in the motor; and supplying a drive signal to an armature winding of the motor. The inverter and the drive signal supplied to the armature winding are based on the detection result of the magnetic pole position detection means so that the drive signal becomes a sine wave signal having a predetermined phase relationship with the rotation phase of the rotor. Inverter control means for controlling the inverter; Wherein the inverter control means,
After starting the motor with a predetermined drive signal, a first synchronous operation control unit that issues a synchronous operation start command after the motor rotational speed reaches a first predetermined rotational speed, and issues a synchronous operation start instruction. After that, until the motor rotation speed exceeds the second predetermined rotation speed, a phase compensation calculation unit that advances the energizing phase of the drive signal by a predetermined amount in comparison with the reference phase, and the motor rotation speed becomes the second rotation speed. And a second synchronous operation control unit for returning the energizing phase of the drive signal to the reference phase after exceeding a predetermined number of rotations.

According to a second aspect of the present invention, there is provided the motor driving device according to the first aspect, wherein the phase compensation calculation unit is configured to perform a transition from the asynchronous operation to the synchronous operation after the motor is started. Prior to advancing the energizing phase of the drive signal by a predetermined amount relative to the reference phase, the energizing phase is delayed from the phase in the asynchronous operation by a predetermined time.

The third aspect of the present invention is the first or second aspect.
The motor drive device according to claim 1, wherein the second predetermined rotation speed is a rotation speed that is equal to or higher than a lower limit value of a normal rotation region of the motor.

According to a fourth aspect of the present invention, in the motor driving apparatus according to any one of the first to third aspects, the inverter control means changes an energizing phase of a drive signal in accordance with a load amount of the motor. It is characterized by including a load amount detecting unit for increasing or decreasing.

According to a fifth aspect of the present invention, there is provided the motor driving device according to any one of the first to fourth aspects, wherein the first neutral point and the second neutral point are connected in series. A series circuit connected via a connected resistor and a capacitor, wherein the magnetic pole position detecting means detects a voltage generated at both ends of the capacitor as a voltage difference between neutral points. It is.

According to a sixth aspect of the present invention, in the motor driving device of the fifth aspect, the magnetic pole position detecting means includes a voltage follower having a voltage at one end of the capacitor as an input signal, and an output of the voltage follower. Signal, a differential amplifier having the other end of the capacitor as an input signal, and a voltage at the other end of the capacitor as a reference voltage, and according to a magnitude comparison between the output of the differential amplifier and the reference voltage. A zero-cross comparator that outputs a binarized signal, wherein the binarized signal output from the zero-cross comparator is output as a position signal.

According to a seventh aspect of the present invention, in the motor driving device according to the fifth aspect, the magnetic pole position detecting means includes a voltage follower having a voltage at one end of the capacitor as an input signal, and an output of the voltage follower. A differential amplifier that receives a signal and a voltage at the other end of the capacitor as input signals, and outputs an analog signal output from the differential amplifier as a position detection signal.

According to an eighth aspect of the present invention, in the motor driving device according to any one of the first to seventh aspects, the inverter control means includes: a delay time associated with processing of the magnetic pole position detection means; A rotation phase of the motor corresponding to a total time with a delay time generated when a signal for controlling the inverter is generated based on the position signal output from the magnetic pole position detection means is calculated based on the rotation speed of the motor. A delay phase calculation unit for performing the operation, and advancing the energization phase of the drive signal by the rotation phase obtained by the delay phase calculation unit.

According to a ninth aspect of the present invention, there is provided the motor driving device according to any one of the first to eighth aspects, wherein the PWM carrier frequency controlled by the inverter control means is a frequency higher than an audible range. It is characterized by the following.

The invention according to claim 10 is the invention according to claims 1 to 9
The motor drive device according to any one of the preceding claims, wherein the inverter control means is configured to control the motor speed higher than a maximum rotation speed determined according to a DC voltage value input to the inverter and a predetermined energization phase. When a rotation speed is required, a high-speed rotation control unit is provided to advance the energization phase from the predetermined energization phase.

The eleventh aspect of the present invention is the first aspect of the present invention.
0, the motor drive device according to any one of claims 1 to 3, further comprising polarity detection means for detecting the polarity of a phase current flowing through the motor,
The inverter control means includes a current polarity correction unit that adds or subtracts a correction value set in advance corresponding to the polarity of a phase current to a command voltage of a drive signal supplied to a motor. .

The twelfth aspect of the present invention is the first aspect of the present invention.
2. The motor drive device according to claim 1, wherein the inverter control device generates a waveform of a drive signal to be supplied to the motor by PWM control using a three-phase modulation method.

The invention according to claim 13 is the invention according to claims 1 to 1
3. The motor drive device according to claim 2, wherein the inverter control unit includes an output voltage correction unit configured to increase or decrease an output voltage to the motor in synchronization with a rotation speed of the motor. is there.

The invention according to claim 14 is the invention as set forth in claims 1 to 1
4. The motor driving device according to claim 3, wherein the motor drives a motor having a permanent magnet disposed inside the rotor.

[0028] The invention according to claim 15 is the invention according to claims 1 to 1.
5. The motor drive device according to claim 4, wherein the stator drives a motor configured by concentrated winding.

The invention according to claim 16 is the invention according to claims 1 to 1
6. The motor drive device according to claim 5, wherein the motor drive device drives a motor of the compressor.

[0030]

Embodiments of the present invention will be described below with reference to the drawings. Elements common to the drawings are denoted by the same reference numerals, and redundant description will be omitted.

Embodiment 1 FIG. 1 is a circuit block diagram of the motor driving device according to the first embodiment of the present invention. In FIG. 1, reference numeral 30 denotes a three-phase DC having a Y-connected stator.
A brushless motor; 32, an inverter for operating the DC brushless motor 30; 34, a DC power supply connected to the inverter 32;
Are connected in parallel with the stator of FIG. 38 is a magnetic pole position detecting means, 40 is an inverter controlling means constituted by a microcomputer or the like, 42 is a phase compensation calculating section,
44 is a synchronous operation control unit, 46 is a PWM generation unit, and 48 is a gate drive unit.

The magnetic pole position detecting means 38 detects the position of the rotor of the DC brushless motor 30 from the potential difference between the neutral point of the DC brushless motor 30 and the neutral point of the resistance circuit 36, and determines the position corresponding to the detected position. Generate a signal. The position signal emitted from the magnetic pole position detecting means 38 is supplied to the phase compensation calculating section 42 of the inverter control means 40. The phase compensation calculation unit 42 calculates the amount of phase compensation to be reflected on the drive signal output from the inverter 32 for the position of the rotor represented by the position signal. The phase compensation amount calculated by the phase compensation calculation unit 42 is supplied to the synchronous operation control unit 44.

The synchronous operation control unit 44 discriminates between the start of the motor 30 and the synchronous operation.
To start synchronous control,
During the synchronous operation, the rotation speed of the motor 30 is controlled based on a rotation speed command supplied from the outside. The PWM generator 46 generates a predetermined PWM signal based on a control signal output from the synchronous operation controller 44. Gate drive unit 4
8 operates the inverter 32 using the PWM signal generated by the PWM generation unit 46.

The inverter 32 includes first and second transistors 50 and 52 and first and second diodes 54 and 56 corresponding to the U phase of the motor 30. The inverter 32 includes first and second transistors 58 and 60 and first and second diodes 62 and 64 corresponding to the V phase of the motor 30. Further, the inverter 32 includes first and second transistors 66 and 68 and first and second diodes 70 and 72 corresponding to the W phase of the motor 30. The first transistors 50, 58, and 66 are disposed between the positive electrode of the DC power supply 34 and each phase coil, while the second transistors 52, 60, 68 are disposed between the negative electrode of the DC power supply 34 and each phase coil. Have been.

The PWM generator 46 and the gate driver 48
Are the six transistors 50 of the inverter 32,
A PWM signal corresponding to each of 52, 58, 60, 66 and 68 is generated. These PWM signals are supplied to a set of transistors (50 and 52, 58 and 6) corresponding to each phase.
0 and a set of 66 and 68) are not simultaneously turned on.

The voltage of the drive signal supplied to the U-phase of the motor 30 is determined by the duty ratio Duty1 of the PWM signal supplied to the first transistor 50 and the duty ratio Duty2 of the PWM signal supplied to the second transistor 52. Ratio Duty1 /
Determined by Duty2. More specifically, the voltage of the drive signal supplied to the U-phase is a multiplication value V * Duty1 / Duty2 of the output voltage V of the DC power supply 34 and the above ratio Duty1 / Duty2.
It becomes the value represented by. Similarly, the voltages of the drive signals supplied to the V-phase and W-phase of the motor 30 correspond to the duty ratios of the PWM signals supplied to the first and second transistors 58 and 60, and the first and second voltages, respectively. The value is in accordance with the duty ratio of the PWM signal supplied to the two transistors 66 and 68.

Therefore, the voltage of the drive signal supplied to each phase of the motor 30 is supplied from the gate drive unit 48 to the inverter 32.
, The output voltage V of the DC power supply 34 can be set to any value up to the upper limit. In the present embodiment, the PWM generator 46 changes the value of the PWM signal such that the voltages of the drive signals applied to the respective phases change sinusoidally with a phase difference of 120 degrees from each other.

In FIG. 1, a resistor circuit 36 has a resistance Y-connected. Therefore, from the neutral point of the resistor circuit 36 (neutral point of the Y connection), a combined voltage of the drive signals output from the inverter 32 toward each phase is output. Therefore, the neutral point of the resistance circuit 36 can be regarded as the potential of the virtual neutral point of the inverter 32.

Hereinafter, a method of detecting the magnetic pole position of the rotor of the DC brushless motor 30 will be described with reference to FIG. Assuming that the inverter 32 outputs a three-phase AC sine wave voltage, the inverter 32 can be replaced with a model of a three-phase AC power supply as shown in FIG.
In this case, the voltage at the neutral point of the inverter 32 can be expressed by the following equation. Vn = sin (αt) + sin (αt + 2 / 3π) + sin (αt + 4 / 3π)

The DC brushless motor 30 has an inductance component and a resistance component. In addition, while the DC brushless motor 30 is rotating, the induced voltage is generated in the coils of each phase by repeating the approach and separation between the coils of each phase and the permanent magnets arranged on the rotor. Therefore, each phase coil of the motor 30 can be a voltage source that generates an induced voltage. The induced voltage generated in each phase of the motor 30 has a main component that fluctuates in a cycle corresponding to the rotation cycle of the motor 30. In addition, the induced voltage generally includes
Many harmonic components including the third harmonic component which fluctuates at three times the frequency of the main component are included. Therefore,
The DC brushless motor 30 can be a model as shown in FIG. In this case, the voltage at the neutral point of the motor 30 can be expressed by the following equation. Vm = sin (wt + ζ) + sin (wt + 2 / 3π + ζ) + sin (wt + 4 / 3π + ζ) + si
n (3wt + ζ) + sin (3 (wt + 2 / 3π) + ζ) + sin (3 (wt + 4 / 3π) + ζ)

From the above two equations, the neutral point voltage Vm of the DC brushless motor 30 and the neutral point voltage of the inverter 32 are calculated.
The difference from Vn, that is, the potential difference signal can be expressed by the following equation. Vmn = Vm-Vn = 3sin (3wt + ζ)

As described above, α related to the phase of the neutral point voltage Vn of the inverter 32 does not remain in the voltage difference signal Vmn. In other words, when the third harmonic is included in the induced voltage of the motor 30, the influence of the phase of the inverter 32 is the third.
It is far below the second harmonic. Therefore, in such a motor 30, the position of the magnetic pole of the rotor is determined based on the third harmonic component of the induced voltage, that is, the potential difference signal Vmn.
Can be accurately detected based on the

The induced voltage generated inside the motor 30 includes:
A harmonic component other than the third harmonic component may be included. Even in such a case, the third harmonic can be accurately detected for the following reason.
That is, a signal including a plurality of harmonics having different orders usually contains more low-order harmonic components. In addition, the third harmonic of the harmonic component is generated by the motor 30 as described above.
The intensity is tripled at the neutral point, but the harmonic signal is not tripled at odd orders other than the tripled order. Therefore, inside the motor 30, only the third harmonic, which is included in the induced voltage, is further amplified by a factor of three, and the fifth and seventh components, which are included next to the third harmonic, are not amplified. For this reason, the third harmonic can be easily detected even when the induced component includes a plurality of harmonic components having different orders.

As described above, according to the magnetic pole position detecting means 38 for detecting the potential difference between the neutral point of the DC brushless motor 30 and the neutral point of the resistance circuit 36, the magnetic pole position detecting means 38 is constituted by the third harmonic component of the induced voltage. The detected potential difference signal can be detected. Therefore, according to the motor driving device of the present embodiment, the magnetic pole position detecting means 38 can accurately detect the magnetic pole position of the rotor of the DC brushless motor 30 based on the potential difference signal.

FIG. 3 is a timing chart for explaining a 120-degree energization method generally used as an energization method for a DC brushless motor. In FIG. 3, U
p, Vp, and Wp indicate the timing at which the drive current flows in the U-, V-, and W-phase coils in the positive direction, respectively. Also,
Un, Vn, and Wn indicate the timing at which the drive current flows through the U-, V-, and W-phase coils in opposite directions, respectively.

In a general driving method of a DC brushless motor, as shown in FIG. 3, a driving current having a pulse width of 120 degrees is sequentially supplied to each phase. In this case, a 60-degree pause section is secured between the time when the forward current flows through the coils of each phase and the time when the reverse current flows. In a DC brushless motor used in such a driving method, an induced voltage generated in each phase coil is detected by measuring a terminal voltage of each coil, and based on the resulting induced voltage, the rotor of the rotor is detected. A technique for detecting a magnetic pole position is widely used.

The period during which the induced voltage can be detected from the terminal voltage of the coil of each phase is limited to the period during which the drive signal is not supplied from the inverter to each phase, ie, the 60-degree pause period. In other words, in the above-described general driving method, it is impossible to detect the magnetic pole position of the rotor unless there is a pause.

As shown in FIG. 3, in the drive method of 120-degree conduction, the waveform of the drive current flowing through the motor is a rectangle of 120 degrees. The torque generated by the motor depends on the value of the current flowing through each phase of the motor. Therefore, if the waveform of the drive current is rectangular, the torque generated by the motor becomes step-like, and large pulsation is likely to occur in the output torque. The torque pulsation causes noise of the motor. Therefore, 120
In the case of using a current-carrying drive system, the motor tends to generate loud noise.

The noise of the motor can be suppressed by smoothing the switching of energization for each phase, that is, by smoothing the fluctuation of the drive current and reducing the torque pulsation. Therefore, in suppressing the noise of the motor, it is more advantageous that the section where the supply of the driving current to each phase is short, that is, the pause section is narrower.

As described above, according to the driving apparatus of this embodiment, even if the motor 30 is energized with a 180-degree sine wave by eliminating the pause period of the driving current, the magnetic pole position detecting means 38 can be used.
, The magnetic pole position of the rotor can be detected. That is, according to the driving device of the present embodiment, the magnetic pole position of the rotor can be detected without using a sensor for detecting the magnetic pole position of the rotor and while supplying a sine wave current to the motor 30. Can be.

If the magnetic pole position of the rotor of the motor 30 can be detected, the phase of the drive signal supplied to each phase of the motor 30 is
In accordance with the rotation phase of the rotor,
0 can be operated synchronously. Therefore, according to the present embodiment, it is possible to realize a driving device capable of synchronously operating the motor 30 with low noise with a simple structure.

By the way, in the DC motor, a sine wave current can flow in an energizing section shorter than 180 degrees, and when the inverter 32 outputs not a sine wave voltage but a trapezoidal voltage, for example. Also, there is a motor that can flow a sinusoidal drive current through each phase. However, such motors are limited to those having a large inductance component. According to the drive device of the present embodiment, the waveform of the current flowing inside the motor can always be sinusoidal regardless of the specifications of the motor. Therefore,
According to the drive device of the present embodiment, noise caused by torque pulsation can be effectively reduced even when any motor is used.

Next, referring to FIGS. 1, 4 and 5,
An operation in which the motor drive device of the present embodiment smoothly pulls the motor 30 into the synchronous operation after starting the motor 30 will be described.

FIG. 4A shows a DC brushless motor 30.
5 shows the potential difference between the neutral point of the resistor circuit 36 and the neutral point of the resistor circuit 36, that is, the waveform of the potential difference signal Vmn. The potential difference signal Vmn includes
A PWM high-frequency component accompanying the on / off of a transistor included in the inverter 32 is included. Magnetic pole position detecting means 3
Reference numeral 8 denotes a voltage waveform whose main component is the third harmonic component included in the induced voltage of the DC brushless motor 30 by removing its high-frequency component by a built-in filter (FIG. 4B).
Is output.

FIG. 5 is a circuit diagram showing an example of the magnetic pole position detecting means 38. As shown in FIG.
Includes a potential difference detection filter 74. The potential difference detection filter 74 is supplied with the potential of the neutral point of the motor 30 and the potential of the neutral point of the resistance circuit. The potential difference detection filter 74 has a function of a filter that removes a PWM high-frequency component from those signals, and an amplification function of inverting and amplifying the potential difference between the signals, that is, the potential difference signal Vmn. The potential difference signal Vmn is processed by the potential difference detection filter 74, so that the potential difference signal Vmn is larger in amplitude and opposite in phase to the signal shown in FIG. 4B, that is, the potential difference signal Vmn shown in FIG. Is converted to a signal having

In this embodiment, the magnetic pole position detecting means 3
Reference numeral 8 has a function of converting the analog signal generated as described above into a digital signal and supplying the digital signal to the phase compensation calculation unit 42 of the inverter control unit 40. The method of transmitting and receiving signals between the magnetic pole position detection means 38 and the inverter control means 40 is not limited to this, and an analog signal is supplied from the magnetic pole position detection means 38 to the inverter control means 40 to control the inverter control. The analog signal may be converted to a digital signal using an A / D conversion port provided in the means 40.

Inside the magnetic pole position detecting means 38, the inverted amplified signal (FIG. 4) generated by the voltage difference detecting filter 74.
(B) is supplied to the zero cross comparator 76. The zero-cross comparator 74 generates a digital signal (FIG. 4 (c)) that changes values before and after the inverted amplified signal crosses the zero position of the signal. The digital signal generated by the zero cross comparator 76 is supplied to an insulating circuit 78 composed of a photo coupler. The insulation circuit 78 transfers the digital signal generated by the zero-cross comparator 76 to the inverter control means 40 while electrically insulating the magnetic pole position detection means 38 from the inverter control means 40 (FIG. 4D).

The inverter control means 40 receives the digital signal supplied from the magnetic pole position detecting means 38 as described above as a position signal representing the magnetic pole position of the rotor. In the present embodiment, the magnetic pole position detecting means 38 includes the resistance circuit 36
The potential difference signal Vmn is detected using the potential at the neutral point as the reference potential. On the other hand, in the inverter control means 40, the negative potential of the DC power supply 34 is used as a reference potential. When the magnetic pole position detecting means 38 and the inverter control means 40 are insulated by the insulating circuit 78 as described above, a circuit can be easily formed even if the two circuits have different reference potentials.

The phase compensation calculator 42 of the inverter control means 40 measures the time between the rising edge and the falling edge of the position signal (FIG. 4D) supplied from the magnetic pole position detecting means 38. The inverter control means 40 has a built-in timer (not shown) for counting the time. The inverter control means 40 can detect the magnetic pole position of the rotor based on the count value of the timer, as described later. The inverter control means 40 calculates an energization phase corresponding to the rotation phase of the motor 30 based on the magnetic pole position detected as described above.

The position signal supplied to the inverter control means 40 is a pulse signal which fluctuates in a cycle corresponding to three times the rotation cycle of the electric angle of the motor 30. Therefore, the rising and falling edges of the signal are 60 electrical degrees.
It can be detected every degree. For this reason, the inverter control means 40 can calculate the time required for the change per 1 electrical angle by dividing the occurrence interval of two adjacent edges by 60.

During operation of the motor 30, a drive signal having a sine waveform is supplied from the inverter 32 to each phase of the motor 30. The rotor of the motor 30 rotates while maintaining a phase substantially corresponding to the phase of the drive signal regardless of whether the rotor is synchronous or asynchronous. Therefore, when the phase of the drive signal supplied from the inverter 32 to the motor 30 is also taken into consideration, one of the position signals supplied for each electrical angle of 60 degrees corresponds to the electrical angle of the rotor of zero degree. To be specified.

Therefore, the inverter control device 40 calculates the position signal supplied from the magnetic pole position detecting means 38 and the count value of the timer (time after the occurrence of an edge) based on the position signal supplied from the magnetic pole position detecting means 38.
The magnetic pole position of the rotor of the motor 30 can be continuously detected from 0 to 360 degrees. For this reason, as shown in FIG. 4E, the inverter control device 40 can generate an energization phase angle that linearly changes from 0 degrees to 360 degrees according to the magnetic pole position of the stator. . Furthermore, the inverter control device 40 can generate the energized phase (FIG. 4 (f)) by advancing the phase with respect to the reference energized phase (FIG. 4 (e)) in the phase compensation calculating unit 42. .

During the operation of the DC brushless motor 30, a position signal is output from the position detecting means 38 as described above.
However, before the motor 30 is started, the rotor is stopped and no induced voltage is generated, so that no position signal is output. Therefore, immediately after the start of the motor 30, it is not possible to generate an energization phase synchronized with the operation of the motor 30 inside the inverter control means 40.

In this embodiment, when the start of the motor 30 is requested, a start command signal is supplied from the synchronous operation control unit 44 to the phase compensation calculation unit 42. Upon receiving the start command signal, the phase compensation calculation unit 42 generates a predetermined phase irrelevant to the position signal from the magnetic pole position detection unit 38, and supplies the phase to the synchronous operation control unit 44. The synchronous operation control unit 44 generates a three-phase AC sine wave signal based on the input phase, and outputs the signal to the PWM generation unit 46. The PWM generation unit 46 determines whether the inverter 32 has a PWM signal based on a signal supplied from the synchronous operation control unit 44.
And generate a PWM signal for the
The inverter 32 is operated by driving the gate driver 48 according to the WM signal.

When the motor 30 is started, the phase corresponding to the position of the rotor is not energized, but the motor 30 operates in a form in which the rotor is attracted to the rotating magnetic field generated in the stator. When the rotation speed of the motor 30 rises to some extent and the magnetic pole position detecting means 38 can output a stable position signal, switching to synchronous operation using the position signal is performed by a conventionally generally used method. Done.

The DC brushless motor 30 is
Has a characteristic that, when a driving voltage whose phase is advanced compared to the most efficient phase for driving (hereinafter, referred to as “optimal phase”) is applied, the induced voltage is distorted. . When the induced voltage is distorted, the third harmonic component increases, and the difference between the neutral point of the motor 30 and the neutral point of the resistance circuit 36, that is, the potential difference signal Vmn increases.

The drive device of the present embodiment utilizes the above-described characteristics of the DC brushless motor 30 to obtain the maximum amount that the motor 30 can follow until the rotation speed of the motor 30 reaches a predetermined rotation speed after the motor 30 is started. Asynchronous operation, that is, operation without using a position signal, is continued in a state where it is predicted that the advance phase will occur. Therefore, according to the driving device of the present embodiment, the potential difference signal Vmn shown in FIG. 4A can be made to have a large amplitude immediately after the motor is started. The magnetic pole position detecting means 38 can output a more accurate position signal more stably as Vmn has a larger amplitude. Therefore, the magnetic pole position detecting means 38 starts to output a stable position signal before the rotation speed of the motor 30 is sufficiently increased.

According to the driving device of this embodiment, the motor 3
0, the synchronization signal using the position signal can be started early after the start. The drive device of the present embodiment drives the motor 30 in a state where the phase is advanced with respect to the above-described optimum phase. If the phase of the drive signal is set to the optimum phase at the same time as the start of the synchronous operation, the harmonic component of the induced voltage decreases, and the magnetic pole position detecting means 38 may not output the position signal properly. According to the drive device of the present embodiment,
Such a malfunction can be prevented by performing the synchronous operation by advancing the phase until the rotation speed sufficiently increases.

When the rotation speed of the motor 30 reaches the lower limit of the normal rotation speed, a signal for notifying the situation is supplied from the synchronous operation control unit 44 to the phase compensation calculation unit 42. Upon receiving the above signal, the phase compensation calculation unit 42 performs processing for delaying the phase of the accelerated drive signal in order to optimize the phase of the drive signal supplied to the motor 30. Specifically, an energization phase is generated that shortens the arrow (advance phase amount) shown in FIG.
After the above processing is performed, the phase of the rotor catches up with the phase of the drive signal, and the optimum phase is realized.

The above starting method is particularly effective when the inverter 32 outputs a sine wave voltage to the motor 30 as in the driving device of the present embodiment. That is, when the voltage output from the inverter 32 is not a sine wave but a distorted voltage, the induced voltage of the motor 30 is distorted. In this case, the potential difference signal Vmn between the motor 30 and the resistance circuit 36 can be easily obtained, so that the position signal can be easily obtained from a region where the rotational speed is relatively low. On the other hand, when the voltage output from the inverter 32 is a sine wave voltage,
The distortion superimposed on the induced voltage is only the distortion due to the arrangement of the permanent magnet in the rotor. Therefore, in this case,
It is difficult to obtain a stable position signal in a region where the motor speed is low.

As in the driving device of the present embodiment, the motor 3
By supplying a sine-wave-like drive signal to 0 and consciously performing the drive signal with the phase of the drive signal immediately after the start of the motor 30, regardless of the specifications of the motor 30,
A sine wave current can be circulated inside the motor, and the motor 30 can be drawn into the synchronous operation relatively early. Therefore, according to the drive device of the present embodiment, regardless of the specification of the motor 30, the motor 30 can be started smoothly while achieving excellent quietness.

Further, according to the driving device of the present embodiment, after the rotation speed of the motor reaches the normal rotation region, the synchronous operation of the motor 30 with the optimum phase is started. Therefore, according to the drive device of the present embodiment, in the normal rotation region,
The motor 30 can be driven with the highest efficiency.

Embodiment 2 FIG. 6 is a time chart for explaining the operation of the motor drive device according to the second embodiment of the present invention. The motor drive device of the present embodiment can be realized by the circuit configuration shown in FIG.

FIG. 6A shows a change in the number of revolutions of the motor 30, and FIG. 6B shows a state of the energizing phase. FIG.
In (b), the direction of the arrow on the vertical axis is the leading direction of the phase. According to the drive device of the present embodiment, as in the case of the first embodiment, the drive signal of the advanced phase is used until the rotation speed of the motor 30 exceeds a predetermined rotation speed (synchronization pull-in rotation speed). Asynchronous operation is performed.

When the rotational speed of the motor 30 exceeds the synchronous pull-in rotational speed, as shown in FIG.
4 outputs a signal requesting the start of the synchronous operation to the phase compensation calculation unit 42. Thereafter, the drive system of the present embodiment changes the operation mode of the motor 30 from the asynchronous operation to the synchronous operation, that is, the phase of the drive signal in accordance with the position of the rotor of the motor 30 detected by the magnetic pole position detection means 38. Switch to the operation that controls.

When switching from the asynchronous operation to the synchronous operation, processing for adjusting the phase of the advanced drive signal to the rotational phase of the motor, that is, processing for delaying the phase of the drive signal is performed. Therefore, when switching from the asynchronous operation to the synchronous operation is performed, a state in which the power supply to the motor 30 is temporarily stopped is realized. As a result, at the time of the above switching, the rotation speed of the motor 30 is temporarily reduced.

The drive device according to the present embodiment, after the rotation speed reaches the synchronous pull-in rotation speed in accordance with the deceleration of the motor rotor accompanying the switching of the operation mode, is performed in a predetermined minute section as shown in FIG. It operates so as to reduce the advance of the phase of the drive signal. Since the minute section differs depending on the specification of the motor 30, it is appropriate to set an appropriate time for each motor 30. In the present embodiment, the phase compensation calculation unit 42 and the synchronous operation control unit 44 operate to accelerate the motor 30 by greatly increasing the energization phase after the lapse of the minute section.

When the rotation speed of the motor 30 reaches the acceleration completion rotation speed, the synchronous operation control unit 44
For requesting the realization of the optimal phase toward (Fig. 6 (d))
Is output. Upon receiving this signal, the phase compensation calculation unit 42 returns the phase of the advanced drive signal to the optimal phase as shown in FIG. Thereafter, the motor 30 with the optimal phase
Is performed. Thereafter, even if the motor 30 is further accelerated, decelerated, or the rotational speed is stabilized,
There is no problem with this activation method.

In FIG. 6, the phase used during execution of the synchronous operation based on the leading phase is shown on the leading side compared to the phase used during the asynchronous operation. It is not limited to this. That is, the phase used during the execution of the synchronous operation by the advance phase is used during the asynchronous operation if it is on the leading side compared to the phase used in the minute section after the motor rotation speed reaches the synchronization pull-in rotation speed. It may be on the lag side compared to the phase to be obtained.

According to the above-described synchronization pull-in method,
Stable start-up of the motor 30 can be guaranteed, and smooth switching from the low-speed state to the synchronous operation can be performed. According to the synchronous operation, the resistance of the motor 30 to a load change or the like can be secured to be larger than that of the asynchronous operation. Therefore, according to the driving device of the present embodiment, the rotation speed of the motor 30 can be increased with a large acceleration from the low rotation region. For this reason, according to the drive device of the present embodiment, the problem of noise and resonance at low speed rotation is solved by instantaneously exceeding the motor rotation speed that coincides with the resonance point of the housing on the low speed side. Can be. As described above, according to the drive device of the present embodiment, not only the quietness of the motor 30 itself can be improved, but also noise and vibration due to resonance of the housing fixed to the motor 30 can be suppressed.

In this embodiment, the motor rotation speed at which the synchronous operation based on the leading phase is switched to the synchronous operation based on the optimum phase, that is, the acceleration completion rotation speed,
When the rotation speed is set to be larger than the lower limit value of the normal rotation region of the motor 30, it is ensured that the magnetic pole position detecting means 38 can easily detect the third harmonic voltage until the motor rotation speed reaches the normal rotation region. Can be. According to such a setting, step-out during acceleration of the motor 30 can be prevented, and the reliability of the motor drive device can be further improved.

Embodiment 3 FIG. 7 is a block diagram of a motor drive device according to Embodiment 3 of the present invention. In FIG. 7, reference numeral 80 denotes a load amount detection unit that detects the load amount of the motor 30. The load amount of the motor 30 is, for example, (1) a combination of the motor current flowing from the inverter 32 to the DC power supply 34 and the output voltage V of the DC power supply 34, and (2) the rotation speed of the motor 30 and the output voltage of the inverter 32. A combination of
(3) a combination of the rotation speed of the motor 30 and the above-described motor current, or (4) when the DC power supply 34 is connected to an AC power supply via an AC / DC converter (not shown),
It can be calculated based on a combination of the input current and the input voltage of the AC power supply and the like.

The load detecting section 80 calculates the load of the motor 30 based on any of the input signals described above. The load amount detection unit 80 outputs a conduction phase angle corresponding to the calculated load amount to the phase compensation calculation unit 42. Phase compensation calculation unit 42
Determines the energization phase of the motor 30 based on the command,
A command is transmitted to the synchronous operation control unit 44. Here, the energization phase angle according to the load amount may be expressed by a mathematical formula,
A configuration in which the data table is provided inside the inverter control means 40 may be adopted.

Although the induced voltage of the motor 30 is generated in proportion to the rotation speed, the output of the motor 30 is determined by multiplying the rotation speed by the torque. When a large generated torque is required, a large drive current flows inside the motor 30. When a large drive current flows inside the motor 30, the motor 30
, The relationship between the rotational position of the motor 30 and the phase of the potential difference signal Vmn changes. The amount by which the relationship between the rotational position and the phase of the potential difference signal Vmn changes is almost uniquely determined according to the load on the motor 30.

For this reason, in the drive device of the present embodiment, the energization phase angle for compensating for the change in the relationship between the rotational position of the motor 30 and the phase of the potential difference signal Vmn is determined based on the load amount of the motor 30 (equation). Alternatively, the calculated value is reflected on the phase of the drive signal. As described above, by changing the energization phase according to the load amount of the motor 30, the motor 30 can always be driven with an appropriate phase according to the load amount. Therefore, according to the driving device of the present embodiment, the motor 30 can always be efficiently driven irrespective of a change in the load amount, while ensuring excellent quietness by sine wave current driving.

Embodiment 4 FIG. 8 is a block diagram of a main part of a motor drive device according to a fourth embodiment of the present invention. In the motor drive device of the present embodiment, the neutral point of the motor 30 and the neutral point of the resistance circuit 36 are connected via a series circuit including a capacitor 82 and a resistor 84. The magnetic pole position detection circuit 38 detects a voltage between both ends of the capacitor 82 as a potential difference signal Vmn. Hereinafter, motor 3
A neutral point between the neutral point of the resistor 82 and the neutral point of the resistor circuit 36
The purpose of connection via the resistor 84 will be described.

When the potentials of the motor 30 and the neutral point of the resistance circuit 36 are directly connected to the voltage difference detecting filter 74 inside the magnetic pole position detecting means 38 without connecting the neutral points, particularly, the potential difference between the two is small. Under the circumstances, the inverter 32
Malfunctions due to switching noise such as The situation where the potential difference between them is small is a phenomenon that occurs mainly when the motor rotation speed is low. In such a case, if a malfunction occurs in the magnetic pole position detecting means 38, it becomes difficult to appropriately pull the motor 30 into the synchronous operation, and the motor 3
0 startup failure is likely to occur. For this reason, in order to obtain stable start-up performance, it is desirable that both neutral points be connected.

When the neutral point between the motor 30 and the resistance circuit 36 is connected via only the resistor 84,
And the potential at the neutral point of the resistor circuit 36 is balanced, and the third harmonic component of the induced voltage of the motor 30 disappears. Therefore, depending on the structure in which the two neutral points are connected via only the resistor 84, the function of accurately detecting the potential difference signal Vmn cannot be satisfied.

On the other hand, the motor 30 and the resistance circuit 36
When the neutral point is connected via the capacitor 82, a connecting portion that exhibits a small impedance with respect to the high frequency component and a large impedance with respect to the low frequency component is provided between the two neutral points. Can be formed. In this case, since the harmonic component of the induced voltage having a frequency three times the rotation cycle of the motor 30 does not disappear, the magnetic pole position detecting means 38 detects the potential difference signal with the same accuracy as when the neutral points are not connected. Vmn can be detected.

Further, according to the capacitor 82, the switching noise of the inverter 32 having a high frequency can be circulated from the resistance circuit 36 to the inverter 32 via the capacitor 82 and the motor 30. Further, by connecting the resistor 84 in series with the capacitor 82 as in the structure of the present embodiment, the high-frequency component flowing between the neutral points can be effectively attenuated. Therefore, by connecting the motor 30 and the neutral point of the resistance circuit 36 via the capacitor 82 and the resistance circuit 84, high frequency components such as switching noise of the inverter 32 flow into the magnetic pole position detecting means 38. It can be effectively prevented.

When the inflow of the high-frequency component into the magnetic pole position detecting means 38 can be prevented, the magnetic pole position detecting means 38 can secure a large noise immunity and detect the potential difference signal Vmn accurately regardless of the presence or absence of high-frequency noise. become. Therefore, according to the motor driving device of the present embodiment, the potential difference signal
A malfunction of the magnetic pole position detecting means 38 in a situation where Vmn is small can be prevented, and stable starting characteristics can be given to the motor 30.

When the neutral point between the motor 30 and the resistor circuit 36 is connected via a capacitor 82 and a resistor 84, and when both ends of the capacitor 24 and a voltage difference detection filter 74 are connected, the motor 30 36, condenser 82,
R by the resistor 84 and the voltage difference detection filter 74
An LC circuit is formed. Depending on the specifications of the motor 30,
For example, due to the resonance phenomenon of the RLC circuit or the like, the impedance of the voltage difference detection filter 74 changes the potential difference between the neutral points,
That is, a state that affects the potential difference signal Vmn may be formed.

FIG. 9 is a block diagram of the magnetic pole position detecting means 38 having a function of eliminating the above-mentioned effects. FIG.
In the magnetic pole position detecting means 38 shown in FIG.
2 is supplied to the voltage difference detection filter 74 as a reference potential, and the potential of the other end of the capacitor 82 is supplied to the potential difference detection filter 74 as a comparison voltage via the voltage follower 26. .

According to the above structure, the magnetic pole position detecting means 3
8 can be prevented from affecting the potential difference between the neutral points. Therefore, the magnetic pole position detecting means 38 shown in FIG. 9 can determine the capacity of the capacitor 82 and the resistor 84 regardless of the specification of the motor 30. That is, the capacitance of the capacitor 82 and the resistor 84 can be set to a value suitable for attenuating a signal component oscillating around the carrier frequency used in the inverter 32 without being limited by the specification of the motor 30.

Further, by eliminating the influence of the impedance of the voltage difference detection filter 74 by using the voltage follower 86, it is possible to detect the voltage difference detection filter 74 and the detection caused by the variation of the components of the circuit connected to the subsequent stage. Errors can be suppressed. Therefore, according to the magnetic pole position detecting means 38 shown in FIG. 9, stable characteristics can be realized together with high noise immunity, and as a result, the reliability of the detection system can be improved.

The magnetic pole position detecting means 38 shown in FIGS. 8 and 9 processes the output of the voltage difference detecting filter 74 by the zero cross comparator 76 and the insulating circuit 78, similarly to the magnetic pole position detecting means 38 shown in FIG. Thus, a digital signal is generated. However, the output signal of the magnetic pole position detecting means 38 is not limited to a digital signal, and an analog signal may be used as an output signal of the magnetic pole position detecting means 38. In this case, the inverter control means 4
It is necessary to pay attention to the reference potential between 0 and the magnetic pole position detecting means 38, and make the reference potential of the inverter control means 38 the same as that of the magnetic pole position detecting means 38, or insulate it with a component such as a transformer. Need to transmit analog signal.

The potential difference between the neutral point of the motor 30 and the resistance circuit 36, that is, the potential difference signal Vmn is shown in FIGS.
Alternatively, the detection may be directly performed by a transformer or the like without using the magnetic pole position detection unit 38 as shown in FIG. Further, the potential difference signal Vmn is a photocoupler between the neutral point of the motor 30 and the resistance circuit 36 (a photocoupler that issues a signal when one of the neutral point potentials is higher than the other neutral point potential). Only the arrangement may be performed to detect.

As described above, by connecting the neutral point between the motor 30 and the resistor circuit 36 with the series circuit composed of the capacitor 82 and the resistor 84, the potential difference signal Vmn can be accurately detected. Thus, a detection circuit having high noise resistance can be configured. Therefore, according to the above structure, there is provided a motor drive device which can easily draw the motor 30 into the synchronous operation from a low rotation speed region, and can realize a position sensorless drive even at a low speed while ensuring excellent quietness. be able to.

Embodiment 5 FIG. FIG. 10 is a block diagram of a motor drive device according to the fifth embodiment of the present invention. In FIG. 10, reference numeral 88 denotes a delay of the energization phase generated by the delay time of the detection circuit of the magnetic pole position detection means 38 and the delay time of the calculation inside the inverter control means 38, and the phase of the drive signal is changed by the delay. It is a lag phase operation unit that operates to advance.

The magnetic pole position detecting means 38 outputs the potential difference signal Vmn
Is detected, and a predetermined delay time occurs until a position signal corresponding to the signal Vmn is output. Similarly, a delay time is generated between the time when the inverter control means 40 receives the position signal issued from the magnetic pole position detection means 38 and the time when the predetermined calculation is completed. These two delay times are always constant. Further, the delay generated in the phase of the drive signal corresponding to the delay time is a value uniquely determined with respect to the rotation speed of the motor.

The delay phase calculating section 88 detects the rotation speed of the motor 30 based on the position signal (FIG. 4D) supplied from the magnetic pole position detection means 38, and determines a predetermined delay in accordance with the rotation speed. Calculate the phase angle corresponding to time. The phase angle calculated by the delay phase calculator 88 is supplied to the phase compensation calculator 42. The phase compensation calculation unit 42 operates to further advance the phase of the drive signal by a delay phase corresponding to a delay time generated by the processing of the magnetic pole position detection means 38 and the inverter control means 40.

As described above, the motor driving device of the present embodiment detects the position of the magnetic pole of the rotor of the motor 30 using the third harmonic component of the induced voltage. That is, the magnetic pole position of the rotor is detected using an induced voltage that oscillates at a frequency three times the frequency of the motor 30. In a general method of detecting the position of the rotor of the motor based on the induced voltage, a three-phase motor can generate three position signals based on the induced voltages obtained in each phase. On the other hand, in the driving device of the present embodiment, only one position signal is obtained. Therefore, the drive device of the present embodiment is required to set an accurate phase based on one position signal.

As described above, in the present embodiment, the phase angle corresponding to the delay time associated with the signal processing is calculated accurately and in a very short time, and the result is converted to the phase of the drive signal output from the inverter 32. Can be reflected.
For this reason, according to the driving device of the present embodiment, reliability such as step-out due to positional deviation is improved as compared with the case where the phase deviation due to the delay time is not compensated, and the motor 3
0 can be driven with higher efficiency.

Embodiment 6 FIG. FIG. 11 is a block diagram of a motor drive device according to Embodiment 6 of the present invention. In FIG. 11, reference numeral 90 denotes a phase compensation calculation unit 4 which, when an instruction for high-speed operation is output from the synchronous operation control unit 44, advances the energization phase until the motor rotation speed reaches the rotation command value.
2 is a high-speed rotation control unit that outputs a command to the control unit 2.

In the DC brushless motor 30, a motor rotation speed proportional to the voltage applied to the motor 30 occurs. Therefore, the maximum rotation speed of the motor 30 is
4 is determined by the maximum DC voltage that can be output.

The stator of the DC brushless motor 30 generates a rotating magnetic field when driving currents having different phases flow through the coils of each phase. The stator of the motor 30 rotates by receiving the rotating magnetic field. When the rotor rotates, an induced voltage corresponding to the number of rotations of the motor is generated in each phase of the motor 30. As a result, the difference voltage between the externally applied voltage and the induced voltage to the motor 30 and the motor 30
Drive current flows according to the impedance of each phase. As the motor speed increases, the induced voltage increases, and it becomes impossible to secure a current for increasing the torque. For this reason, the maximum rotation speed of the motor 30 is limited to a value according to the externally applied voltage.

The maximum rotation speed of the motor 30 can be increased by reducing the induced voltage generated inside the motor. The magnitude of the induced voltage generated inside the motor is determined by the flux linkage generated by the permanent magnet of the rotor and the angular velocity of the rotor. In the motor 30, when the phase of the drive signal is advanced, the excitation component of the drive current flowing through the motor 30 increases, and a magnetic flux component that weakens the linkage magnetic flux caused by the permanent magnet is generated on the stator side. become. As a result, when the phase of the drive signal is advanced, the flux linkage caused by the permanent magnet is apparently reduced,
The induced voltage generated inside the motor is reduced. Therefore,
By advancing the phase of the drive signal, it is possible to increase the maximum number of revolutions of the motor 30 as compared with a case where a drive signal having an optimal phase is used.

In a general method for detecting the position of the stator without using a position sensor, an induced voltage is detected on the basis of the terminal voltage of each phase during an energization suspension period in which energization to each phase of the motor is stopped. Is performed. In such a position sensorless system, the presence of a pause section is required, so there is a limit to the phase that can be advanced, and if the amount of phase advance exceeds that limit, the position of the stator cannot be detected. There were drawbacks. In contrast, according to the sensorless method used in the present embodiment,
Since there is no need to provide an energization pause section, there is no limit on the amount by which the phase is advanced, and it is possible to weaken the linkage flux of the permanent magnet as much as possible. Therefore, according to the motor drive device of the present embodiment, the maximum rotation speed of the motor 30 can be sufficiently increased.

As described above, the maximum rotation speed of the motor 30 is:
By increasing the phase of the drive signal beyond the optimum phase, it can be increased. However, if the phase of the drive signal is advanced beyond the optimum phase, there is a problem that the efficiency of the motor 30 is reduced.

By the way, the induced voltage generated in each phase of the motor 30 has a larger value as the inductance of the coil of each phase is larger, that is, as the number of windings of each phase coil is larger. The larger the number of permanent magnets, the larger the value. Therefore, when the maximum number of revolutions of the motor 30 is limited by the externally applied voltage, the number of turns of the coil is also limited to ensure the maximum number of revolutions. In contrast, as in the present embodiment,
If the limitation on the maximum number of rotations by the externally applied voltage can be released, the specification of the motor 30 can be changed to increase the number of windings of the coil and the amount of permanent magnets used in the rotor.

If the number of windings of the coil provided in the motor 30 is increased to increase their inductance, the impedance of each phase with respect to high frequency can be increased. When the high-frequency impedance of each phase is improved, high-frequency iron loss inside the motor due to a signal near the carrier frequency used by the inverter 32 is suppressed. Therefore, when the number of turns of the coil increases, the efficiency of the motor 30 in the low speed / medium speed region can be increased. Further, since the number of permanent magnets can be increased, the motor torque can be generated with a small current, and the efficiency of the motor 30 can be increased.

Therefore, by driving the motor 30 having a coil having a large number of windings or the motor 30 having an increased amount of magnets by the motor driving device of the present embodiment, the efficiency near the maximum speed region is somewhat reduced. However, a sufficiently high efficiency can be ensured in the normal use region of the actual product, that is, in the rotation speed region where the ratio used in the actual product is high. For this reason, according to the motor drive device of the present embodiment, it is possible to reduce the power consumption of the product in a daily use environment, and as a result, to improve the energy saving performance of the product.

Embodiment 7 FIG. FIG. 12 is a block diagram of a motor drive device according to Embodiment 7 of the present invention. In FIG. 12, reference numeral 92 denotes a polarity detection unit for detecting the polarity of the current flowing through each phase of the motor 30, and 94 denotes a current polarity correction unit that corrects the output voltage of the inverter 32 according to the polarity of the current flowing through each phase. . In the present embodiment, the polarity detector 94 is configured as circuit hardware, and the current polarity corrector 9
Reference numeral 4 denotes software inside the inverter control means 40.

The inverter 32 has a motor 3 by appropriately controlling six transistors 50, 52, 58, 60, 66 and 68 provided therein.
A sine wave voltage is output for each phase of 0. At this time, the PWM control of these transistors is performed so that a set of transistors connected in series does not fire at the same time so as to prevent a short circuit in the circuit. It is performed so as to be simultaneously turned off for a very short time.

A pair of transistors 50 corresponding to the U-phase
When the switches 52 are turned off at the same time, a circulating current due to the inductance component of the motor 30 flows through one of the diodes 54 and 56 connected in parallel with the components. When the above circulating current flows through the diode 54,
After the two transistors 50 and 52 are turned off at the same time, the positive voltage of the DC power supply 34 is supplied to the U phase for a very short time. On the other hand, when the above-mentioned circulating current flows through the diode 56, the negative voltage of the DC power supply 34 is supplied to the U phase for a very short time after the two transistors 50 and 52 are turned off simultaneously.

The PWM control of the transistors 50 and 52 is as follows.
The time during which the positive voltage of the DC power supply 34 is applied to the U phase coincides with the on-time of the transistor 50.
The time during which the negative electrode voltage is applied to the U phase
This is performed on the assumption that the on-time matches the on-time. Therefore, the two transistors 5
If a positive voltage or a negative voltage is applied to the U phase while 0 and 52 are off, an error occurs in the drive voltage of the U phase by the amount of application. The drive voltage error described above also occurs in the V phase and the W phase as in the U phase.

For this reason, the waveform of the drive voltage output from the inverter 32 toward each phase is obtained by slightly distorting the sine waveform originally intended for the PWM control. When such a distortion is included in the drive voltage output from the inverter 32, the assumption of the model shown in FIG. 2, that is, the assumption that the inverter 32 outputs a sine wave with three-phase alternating current is broken. Therefore, in this case, it is necessary to consider that the voltage distortion generated inside the inverter 32 is input to the magnetic pole position detecting means 38 as a harmonic component.

When the harmonic component generated inside the inverter 32 is small, the component does not give a problem to the driving characteristics of the motor 30. However, when the harmonic component increases, a situation occurs in which the magnetic pole position detecting means 38 detects not the harmonic component of the motor 30 but the harmonic component of the inverter 32 as the potential difference signal Vmn. In this case, since the motor driving device attempts to drive the motor 30 based on the harmonic component generated by the inverter 32, step-out easily occurs particularly in a high-speed region.

When the motor 30 is driven by a sinusoidal current, the noise accompanying the driving tends to concentrate near the carrier frequency of the PWM control. For this reason, when the motor 30 is driven by using the sine wave current, if the carrier frequency of the PWM control is set to be equal to or higher than the audible frequency of a human, the electromagnetic noise from the motor 30 is completely inaudible to humans, and thus is closer to noiseless. Become. However, the harmonic component output from the inverter 32 increases as the carrier frequency used by the inverter 32 for PWM control increases. Therefore, PWM
If a carrier frequency exceeding the audible frequency is used in the control, a large harmonic component is likely to be output from the inverter 32.

As described above, the harmonic component output from the inverter 32 is generated by the circulation of the circulating current after the set of transistors provided for each phase of the motor 30 is simultaneously turned off. DC power supply 3 for each phase for a very short time
4 is generated when the potential of 4 is supplied. Therefore, by correcting the on-time of each transistor and canceling the influence of the voltage supply from the DC power supply 34 during the minute time, the waveform of the drive voltage output from the inverter 32 can be made into a sine wave.

The direction of the circulating current generated after a pair of transistors are simultaneously turned on is determined by the polarity of the driving current flowing through each phase. Further, the amount of distortion generated in the drive voltage due to the above-described circulating current flowing through the diode is substantially constant with respect to the carrier frequency of the PWM control. Therefore, if the drive duty of a set of transistors corresponding to each phase is corrected by a predetermined amount according to the polarity of the drive current, the output voltage of the inverter 32 can be corrected to a sine wave.

In the motor driving device of the present embodiment, the polarity of the driving current flowing through each phase of the motor 30 is detected by the polarity detecting means 92. The polarity detection unit 92 outputs the detected polarity to the current polarity correction unit 94. The current polarity correction unit 94 determines the direction of circulation of the circulating current according to the polarity of the drive current flowing through each phase, and outputs a voltage correction amount for canceling the influence to the PWM generation unit 46. The PWM generating unit 46 corrects the PWM signal supplied to each transistor of the inverter 32 by adding the voltage correction amount to the applied voltage instructed by the synchronous operation control unit 44. As a result, the drive voltage supplied from the inverter 32 to the motor 30 is corrected to a sine wave. The voltage correction amount is PWM
If the carrier frequency of the control is constant, a constant value may be used. Therefore, the carrier frequency may be stored in the current polarity correction unit 94 from the beginning.

Since the motor driving device of this embodiment operates as described above, even if the carrier frequency of the PWM control used in the inverter 32 is high, the magnetic pole position means 38 causes the potential difference signal Vmn by the harmonic signal of the motor 30 to be high. Can be detected. Therefore, according to the motor driving device of the present embodiment, in addition to the fact that the noise of the motor 30 can be reduced by using the sine wave current, the frequency component of the noise can be reduced as described above by using the carrier frequency higher than the audible frequency. It is possible to concentrate on the carrier frequency, and the noise of the inverter 32 can be reduced. Therefore, according to the motor drive device of the present embodiment, it is possible to realize even better noise reduction than the other drive devices described above.

Incidentally, in the above embodiment, P
Although no particular reference is made to the method by which the WM generation unit 46 generates a PWM signal, it is effective in the apparatus of the present embodiment to cause the PWM generation unit 46 to execute PWM generation by three-phase modulation. Voltage supply by three-phase modulation is a method of applying a sinusoidal voltage to each phase coil, instead of changing the applied voltage of each phase coil to an apparent sinusoidal shape. Therefore, according to the voltage supply by the three-phase modulation, harmonic components of the voltage output from the inverter 30 can be effectively suppressed, and the detection accuracy of the magnetic pole position can be improved.

Further, in the above-described embodiment, the current polarity correction section 94 performs only the correction in accordance with the polarity of the drive current. However, the present invention is not limited to this. The unit 94 may perform voltage correction in synchronization with the number of rotations of the motor 30 during one rotation. That is, the number of rotations of the motor 30 changes according to the increase and decrease of the load applied to the motor 30 during one rotation. By causing the current polarity correction unit 94 to perform the voltage correction synchronized with the rotation speed, when the rotation speed fluctuates due to the load fluctuation during one rotation of the motor 30, the third order of the induced voltage of the motor 30 is obtained. Variations in harmonic components can be suppressed. Therefore, by executing the above processing, the accuracy of detecting the magnetic pole position can be further improved, and the reliability of the motor drive device can be improved.

In the above embodiment, the PWM
Although the control carrier frequency is set to be higher than the audio frequency, there is no problem if the frequency is lower than the audio frequency. In other words, the term “above the audible frequency” generally means about 16 kHz, but the carrier frequency applied to the driving device of the present embodiment may be about 10 kHz, and there is no problem if it is less than 10 kHz.

FIGS. 12 and 13 are plan views of the rotor of the DC brushless motor, respectively. The rotor 96 shown in FIG. 12 has a permanent magnet 9 embedded inside a magnetic body.
8 is provided. On the other hand, the rotor 100 shown in FIG.
A permanent magnet 102 is provided in the vicinity of the surface in a ring shape. A DC brushless motor using the rotor 96 (hereinafter referred to as an “embedded motor”) has an advantage that a higher operating efficiency can be obtained as compared with a DC brushless motor using the rotor 100, but has a larger torque ripple. There is a problem that noise is easily generated.

In an embedded motor, a ratio determined according to the embedded shape of the permanent magnet 98 (hereinafter referred to as “salient pole ratio”) is defined. The larger the salient pole ratio of the embedded motor, the more effectively the reluctance torque, that is, the torque generated when the rotor 96 is attracted to the electromagnet on the stator side, can be used more effectively. For this reason, the efficiency of the embedded motor increases as the salient pole ratio of the stator increases. On the other hand, in the embedded motor, torque ripple occurs according to the salient pole ratio of the stator. For this reason, the stator of the embedded motor is limited to a salient pole ratio that does not generate a problematic noise.

The motor driving devices according to the first to seventh embodiments drive the DC brushless motor 30 with a sine wave signal. The sine wave signal is a signal effective in suppressing the torque ripple of the motor 30. Therefore, according to those motor driving devices, a high-efficiency motor having a large salient pole ratio can be driven while sufficiently suppressing the noise level.

FIGS. 15 and 16 are plan views of the stator of the DC brushless motor, respectively. The stator 104 shown in FIG. 15 is configured by a winding method called distributed winding. On the other hand, the stator 106 shown in FIG. 16 is configured by a winding method called concentrated winding. According to the stator 106 using the concentrated winding, a higher operating efficiency can be provided to the DC brushless motor than the stator 104 using the distributed winding. However, concentrated winding
There is a problem that a loud noise is easily generated as compared with the distributed winding.

As described above, the motor driving devices of the first to seventh embodiments are devices that can drive the motor with low noise by using the sine wave current as the driving current. Therefore, according to those motor driving devices, the motor including the stator 106 using concentrated winding can be efficiently driven with low noise.

As described above, according to the motor driving devices of the first to seventh embodiments, it is possible to easily apply a motor having high efficiency but having a problem in measures against noise to a product. Also, by applying these technologies,
The compressor can be configured using a high-efficiency motor whose application has been suspended due to noise problems. According to such a compressor, a great effect can be obtained particularly in a refrigerator or a refrigerator where the compressor is disposed indoors.

[0133]

Since the present invention is configured as described above, it has the following effects. Claim 1
According to the described invention, D is provided without providing the magnetic pole position detection sensor.
The reliability of startup in a sensorless motor driving device that drives a C brushless motor can be improved.
Further, by outputting a sine wave voltage from the inverter, excellent quietness can be realized, and the motor can be efficiently driven. Furthermore, at a steady rotation speed, the motor can be driven with the highest efficiency by optimizing the energization phase.

According to the second aspect of the present invention, the motor can be started stably, and the synchronous operation can be started from a relatively low rotation speed region. For this reason, it is possible to instantaneously exceed the resonance point of the housing on the low speed side, and it is possible to solve the problem caused by noise and resonance at low speed rotation. As a result, not only a motor drive device having excellent quietness can be provided, but also noise and vibration due to resonance of a housing to which the motor is attached can be suppressed.

According to the third aspect of the invention, the motor rotation speed for returning the phase of the drive signal to the optimum phase is set higher than the minimum rotation speed under actual use conditions. For this reason, until the motor rotation speed reaches the minimum rotation speed, the state where the magnetic pole position detecting means can easily detect the third harmonic voltage continues. As a result, step-out during acceleration can be prevented, and the reliability of the motor drive device is improved. Further, since the magnetic pole position can be detected without detecting an unstable third harmonic voltage in a low speed region, a stable magnetic pole position detection signal can be output, and the motor can be driven stably.

According to the fourth aspect of the present invention, the motor can be driven at an appropriate phase according to the load by changing the energization phase according to the load of the motor. Therefore, according to the present invention, it is possible to effectively prevent the motor efficiency from deteriorating due to the change in the load amount, while ensuring excellent quietness by driving the sine wave current.

According to the fifth aspect of the present invention, by connecting the neutral point with the series circuit of the capacitor and the resistor, a detection circuit which is strong against noise is configured while ensuring the performance of detecting the potential difference signal. be able to. Therefore, according to the present invention, the motor can be drawn into the synchronous operation from a low rotational speed region, and the position sensorless drive can be realized even at a low speed while ensuring excellent quietness by driving the sine wave current.

According to the invention of claim 6, since the influence of the impedance is eliminated by the voltage follower, the capacity of the capacitor or the resistor can be determined regardless of the specification of the motor. Therefore, high-frequency components around the carrier frequency used in the inverter can be easily attenuated, and the noise immunity is improved. In addition, since there is no variation in detection accuracy due to variations in components constituting the magnetic pole position detecting means, the reliability of the detection system can be improved.

According to the seventh aspect of the present invention, since the analog signal is transmitted from the position detecting means, malfunction due to noise can be prevented, and the reliability of the motor driving device can be improved.

According to the eighth aspect of the present invention, it is possible to perform phase compensation for canceling a minute delay time due to detection of a position signal. Therefore, according to the present invention, the driving efficiency of the motor can be improved and the quietness can be improved. Further, the possibility of step-out can be reduced and reliability can be improved.

According to the ninth aspect of the present invention, it is possible to detect the magnetic pole position even when the carrier frequency used in the inverter is high. For this reason, according to the present invention, it is possible to configure a noiseless inverter using a carrier frequency higher than the audio frequency, that is, an inverter whose noise peak frequency (concentrated near the carrier frequency) exceeds the human audio frequency. Therefore, according to the present invention, it is possible to realize the noise reduction of the inverter in addition to the noise reduction accompanying the reduction of the torque ripple due to the sine wave current.

According to the tenth aspect of the present invention, the maximum rotational speed of the motor can be increased by advancing the driving phase. For this reason, according to the present invention, it is possible to form an advantageous state for increasing the driving efficiency of the motor in the actual use area. Therefore, according to the present invention, it is possible to reduce the power consumption when the product is used on a daily basis, and to improve the energy saving performance of the product to which the product is applied.

According to the eleventh aspect of the present invention, a predetermined voltage correction according to the polarity of the phase current of the motor can be applied to the drive signal. According to the above correction, distortion superimposed on the drive signal in accordance with the execution of the PWM control can be corrected, and the waveform thereof can be accurately made into a sine wave. Therefore, according to the present invention, it is possible to effectively reduce the torque ripple of the motor and realize excellent quietness.

According to the twelfth aspect of the present invention, by performing PWM generation by three-phase modulation in the PWM generation unit, harmonic components of the voltage output from the inverter can be reduced, and the accuracy of magnetic pole position detection can be improved. Becomes possible.

According to the thirteenth aspect of the present invention, voltage correction synchronized with the number of rotations of the motor during one rotation is performed.
Variations in the third harmonic component of the induced voltage due to rotation speed fluctuations caused by load fluctuations during one rotation of the motor can be suppressed. Therefore, according to the present invention, the reliability of the motor drive device can be improved by increasing the detection accuracy of the magnetic pole position and detecting the stable third harmonic voltage.

According to the fourteenth aspect of the present invention, it is possible to quietly drive an embedded motor that has high efficiency but has a problem in noise control. Therefore, according to the present invention, a motor drive system that is excellent in silence and excellent in efficiency can be configured.

According to the fifteenth aspect of the present invention, it is possible to quietly drive a concentrated winding motor which has a high efficiency but has a problem in countermeasures against noise. Therefore, according to the present invention, a motor drive system that is excellent in silence and excellent in efficiency can be configured.

According to the sixteenth aspect of the present invention, it is possible to realize a compressor drive system which is excellent in silence and high in efficiency. According to the present invention, in particular, by applying to a refrigerator or a dehumidifier that arranges a compressor indoors,
A great effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a block diagram of a motor drive device according to a first embodiment of the present invention.

FIG. 2 is a diagram showing a model of the motor driving device shown in FIG. 1;

FIG. 3 is a diagram for explaining a general driving method of a DC brushless motor.

FIG. 4 is a timing chart for explaining the operation of the motor drive device shown in FIG.

FIG. 5 is a circuit diagram of magnetic pole position detecting means provided in the motor drive device shown in FIG.

FIG. 6 is a timing chart for explaining an operation of the motor drive device according to the second embodiment of the present invention.

FIG. 7 is a block diagram of a motor drive device according to a third embodiment of the present invention.

FIG. 8 is a circuit diagram illustrating an example of a magnetic pole position detecting unit included in a motor driving device according to a fourth embodiment of the present invention.

FIG. 9 is a circuit diagram of another example of the magnetic pole position detecting means provided in the motor driving device according to the fourth embodiment of the present invention.

FIG. 10 is a block diagram of a motor drive device according to a fifth embodiment of the present invention.

FIG. 11 is a block diagram of a motor drive device according to a sixth embodiment of the present invention.

FIG. 12 is a block diagram of a motor drive device according to a seventh embodiment of the present invention.

FIG. 13 is a plan view of an example of an embedded permanent magnet rotor.

FIG. 14 is a plan view of an example of a surface-positioned permanent magnet rotor.

FIG. 15 is a plan view of an example of a distributed winding type stator.

FIG. 16 is a plan view of an example of a concentrated winding type stator.

FIG. 17 is a block diagram of a conventional motor drive device.

[Explanation of symbols]

Reference Signs List 30 motor, 32 inverter, 34 DC power supply, 36 resistance circuit, 38 magnetic pole position detecting means, 40 inverter control means.

Claims (16)

[Claims] 1. A motor driving device for driving a motor having a stator having a plurality of Y-connected armature windings and a rotor having a plurality of poles formed by permanent magnets, Y to be connected in parallel with each of the lines
A resistor circuit having a plurality of connected resistors; a first neutral point formed at a connection center of the plurality of resistors; and a second neutral point formed at a connection center of the plurality of armature windings.
Magnetic pole position detecting means for outputting a position signal corresponding to the magnetic pole position of the rotor based on a voltage difference from a neutral point; an inverter for supplying a drive signal to an armature winding of the motor; and the armature. Inverter control for controlling the inverter based on the detection result of the magnetic pole position detection means so that the drive signal supplied to the winding becomes a sine wave signal having a predetermined phase relationship with the rotation phase of the rotor. Means for starting the motor with a predetermined drive signal, and then issuing a synchronous operation start command after the motor speed reaches a first predetermined speed. An operation control unit, after a synchronous operation start command is issued, until the motor speed exceeds a second predetermined speed, a phase compensation for advancing the energizing phase of the drive signal by a predetermined amount compared to the reference phase. Arithmetic unit and Motor driving apparatus which the motor speed, characterized in that it comprises a second synchronous operation control unit to return to the reference phase of the power-on phase of the drive signal after exceeding the predetermined rotational speed of the second. 2. The phase compensation calculation section, when a transition from asynchronous operation to synchronous operation is performed after the motor is started, advances the energizing phase of the drive signal by a predetermined amount compared to the reference phase. 2. The motor drive device according to claim 1, wherein prior to the step, the energization phase is delayed from the phase in the asynchronous operation by a predetermined time. 3. The motor drive device according to claim 1, wherein the second predetermined rotation speed is a rotation speed that is equal to or higher than a lower limit value of a normal rotation region of the motor. 4. The inverter control device according to claim 1, wherein the inverter control unit includes a load amount detection unit that increases / decreases a conduction phase of a drive signal according to a load amount of the motor. Motor drive. 5. A series circuit for connecting the first neutral point and the second neutral point via a resistor and a capacitor connected in series, wherein the magnetic pole position detecting means comprises: The motor drive device according to claim 1, wherein a voltage generated between both ends of the capacitor is detected as a voltage difference between neutral points. 6. The magnetic pole position detecting means includes: a voltage follower having a voltage at one end of the capacitor as an input signal; a differential signal having an output signal of the voltage follower and a voltage at the other end of the capacitor as an input signal. An amplifier; and a zero-cross comparator that outputs a binary signal according to a magnitude comparison between the output of the differential amplifier and the reference voltage, using a voltage at the other end of the capacitor as a reference voltage, and an output from the zero-cross comparator. 6. The motor drive device according to claim 5, wherein the binarized signal is output as a position signal. 7. The magnetic pole position detecting means includes: a voltage follower having a voltage at one end of the capacitor as an input signal; a differential signal having an output signal of the voltage follower and a voltage at the other end of the capacitor as an input signal. The motor driving device according to claim 5, further comprising an amplifier, wherein the analog driving unit outputs an analog signal output from the differential amplifier as a position detection signal. 8. The method according to claim 1, wherein the inverter control means generates a signal for controlling the inverter based on a delay time associated with the processing of the magnetic pole position detecting means and a position signal output from the magnetic pole position detecting means. A delay phase calculation unit that calculates a rotation phase of the motor corresponding to a total time with the generated delay time based on the number of rotations of the motor, and the drive signal of the drive signal corresponding to the rotation phase obtained by the delay phase calculation unit. 2. The power supply phase is advanced.
The motor drive device according to any one of claims 1 to 7. 9. The motor drive device according to claim 1, wherein the PWM carrier frequency controlled by the inverter control means is a frequency higher than an audible range. 10. The inverter control means according to claim 1, wherein a high-speed motor rotation speed is required as compared with a maximum rotation speed determined according to a DC voltage value input to the inverter and a predetermined energizing phase. The motor drive device according to any one of claims 1 to 9, further comprising a high-speed rotation control unit that advances an energization phase from the predetermined energization phase. 11. A polarity detecting means for detecting the polarity of a phase current flowing through a motor, wherein the inverter control means sets a command voltage of a drive signal supplied to the motor in advance corresponding to the polarity of the phase current. The motor drive device according to claim 1, further comprising a current polarity correction unit configured to add or subtract the corrected correction value. 12. The motor drive according to claim 1, wherein the inverter control device generates a waveform of a drive signal supplied to the motor by PWM control using a three-phase modulation method. apparatus. 13. The inverter control device according to claim 1, wherein the inverter control unit includes an output voltage correction unit that increases or decreases an output voltage to the motor in synchronization with a rotation speed change during one rotation of the motor. The motor drive device according to claim 1. 14. A motor for driving a motor in which a permanent magnet is arranged inside a rotor.
The motor drive device according to any one of claims 1 to 4. 15. The motor driving device according to claim 1, wherein the stator drives a motor configured by concentrated winding. 16. The motor drive device according to claim 1, wherein a motor of the compressor is driven.