JP6477705B2 - DC motor driving apparatus and DC motor driving method - Google Patents

Description

  The present invention relates to a DC motor driving apparatus that drives a motor, and more particularly to a DC motor driving apparatus and a DC motor driving method that can be sinusoidally driven from the time of startup.

  Patent Documents 1 and 2 are known as conventional DC motor driving devices. The DC motor driving device described in Patent Document 1 instructs an address counter on a frequency value that gradually increases as time passes, and an AC command value for each phase of the motor based on data on an address output by the address counter. And the motor is driven by exciting with a sine wave drive system.

  The DC motor driving device described in Patent Document 2 estimates the rotor position by analyzing the output of the magnetic sensor in an analog manner using an A / D converter, and excites the motor by exciting it using a sine wave driving method. To drive.

JP-A-10-225164 JP 2013-66324 A

  Patent Document 2 describes that a motor can be easily driven by an A / D converter. However, since a one-chip microcomputer generally has only one A / D converter, a multiplexer is used. Switch between the three magnetic sensors. Considerable time is required to measure the outputs of the three magnetic sensors.

  Furthermore, when it is necessary to calculate an inverse trigonometric function, it takes a long time to determine an actually required excitation pattern. The above calculation can be performed at the start of motor start-up, but as the motor rotation speed increases, the confirmation of the excitation pattern is delayed and the motor rotation breaks down. In addition, even when the motor is started, a start failure may occur. For example, it is impossible to start forward rotation of a fan blade rotating in the reverse direction by being blown by the wind. This is because when the excitation pattern is confirmed, the rotor has moved to a position different from the already measured rotor position.

  In Japanese Patent Laid-Open No. 2004-260688, only by performing excitation that gradually increases the frequency by the sine wave drive method, a start failure occurs when the load is large or the rotor position at the start is unexpected.

  Therefore, in order to start the motor reliably without starting failure, the conventional sine wave driving device drives the motor with a rectangular wave at the time of starting, and when the rotational speed reaches a predetermined rotational speed, We switched to wave drive.

  FIG. 8 is a timing chart showing a three-phase Hall sensor output waveform and a three-phase duty waveform in rectangular wave driving of a conventional DC motor driving device. FIG. 8 shows changes in the Hall sensor output and the corresponding PWM duty when rotating at a constant speed during rectangular wave driving.

A conventional DC brushless motor with a magnetic sensor has three Hall sensors corresponding to the UVW phase, and the output of the Hall sensor is 2 ³ by a combination of high (H) and low (L). -2 = 6. This is because there are no HHH and LLL. For this reason, it is possible to determine in which electrical angle 360 ° / 6 = 60 ° (the range of the electrical angle 60 ° is called a sector). If it is known in which sector the rotor is located, rectangular wave driving is possible, that is, rectangular wave driving is possible only by sector information.

  However, in order to drive the sine wave, more detailed rotor position information is required. If the rotational speed exceeds a certain level, the detailed position of the rotor can be estimated on the assumption that the next sector advances in the same manner at the current rotational speed. However, this estimation method cannot be used when starting from a state where the rotor is stopped.

  In addition, when a conventional sine wave driving device is used for a DC brushless motor fan or the like that has recently been commercialized and attracts attention, there is a problem in that noise is generated during rectangular wave driving at the time of start-up and the quietness is impaired.

  An object of the present invention is to provide a DC motor driving apparatus and a DC motor driving method capable of starting a motor while maintaining quietness without causing a starting failure by sine wave driving.

In order to solve the above problems, a DC motor driving apparatus according to the present invention includes a magnetic flux detection unit that detects magnetic flux of a rotor of a motor and outputs a magnetic flux detection signal, and a rotor that detects a sector of the rotor based on the magnetic flux detection signal. A position detection circuit, and a control circuit that outputs an angle signal from a start point to an end point of the rotor sector and restarts output of the angle signal of the same sector when there is no movement of the rotor sector based on the magnetic flux detection signal; A sine wave generating circuit for generating a sine wave signal for driving the motor in a sine wave based on the angle signal, a drive duty is created based on the sine wave signal, and a switching element is turned on / off by the drive duty to and a motor driving unit for driving the motor, and the rotational speed detecting circuit for detecting the rotational speed of the rotor based on the magnetic flux detection signal, An automatic control circuit that performs an operation based on the rotational speed and speed command of the rotor detected by the rotational speed detection circuit and outputs a control output to the control circuit, and the control circuit includes the automatic control circuit The amplitude of the angle signal is determined in accordance with the control output from the controller, and when there is no movement of the sector of the rotor, the amplitude of the angle signal of the same sector is made larger than the amplitude of the previous angle signal.

  According to the DC motor driving device of the present invention, the control circuit outputs the angle signal of the same sector again when there is no movement of the rotor sector based on the magnetic flux detection signal.

  That is, excitation corresponding to a sine wave is performed from the start point to the end point of the current sector, and when the magnetic flux detection signal does not change in that sector, that is, when the rotor does not rotate, the angle signal of the same sector is again obtained by the angle signal of the same sector. By resuming excitation, sinusoidal wave driving can be performed.

Therefore, it is possible to provide a DC motor driving device that can start a motor while maintaining quietness without causing a starting failure by sine wave driving. Further, the control circuit determines the amplitude of the angle signal in accordance with the control output from the automatic control circuit, and when there is no movement of the rotor sector, the amplitude of the angle signal of the same sector is made larger than the amplitude of the previous angle signal. Therefore, a PWM duty that generates a larger torque can be obtained, and the motor can be sine-wave driven more smoothly.

FIG. 1 is a circuit configuration diagram of the DC motor driving apparatus according to the first embodiment. FIG. 2 is a timing chart showing a three-phase hall sensor output waveform and a three-phase duty waveform when the motor is rotating at a constant speed in the DC motor driving apparatus of the first embodiment. FIG. 3 is a timing chart showing a three-phase hall sensor output waveform and a three-phase duty waveform when the DC motor driving apparatus according to the first embodiment is started. FIG. 4 is a circuit configuration diagram of the DC motor driving apparatus according to the second embodiment. FIG. 5 is a timing chart showing a three-phase hall sensor output waveform and a three-phase duty waveform when the DC motor driving apparatus according to the second embodiment is started. FIG. 6 is a timing chart showing a three-phase Hall sensor output waveform and a three-phase duty waveform when the DC motor driving apparatus of Example 3 is started. FIG. 7 is a timing chart showing a three-phase Hall sensor output waveform and a three-phase duty waveform when the DC motor driving apparatus of Example 4 is started. FIG. 8 is a timing chart showing a three-phase Hall sensor output waveform and a three-phase duty waveform in rectangular wave driving of a conventional DC motor driving device.

  Hereinafter, embodiments of a DC motor driving apparatus and a DC motor driving method of the present invention will be described in detail with reference to the drawings.

Example 1
FIG. 1 is a circuit configuration diagram of the DC motor driving apparatus according to the first embodiment. FIG. 2 is a timing chart showing a three-phase hall sensor output waveform and a three-phase duty waveform when the motor is rotating at a constant speed in the DC motor driving apparatus of the first embodiment. As shown in FIG. 2, in order to drive the motor in a sine wave, various duties are required even in the same sector, and sector information alone is insufficient, and more detailed rotor position information is required.

  The DC motor driving apparatus shown in FIG. 1 includes Hall sensors 1, 2, 3, a rotor position detection circuit 13, a controller 14, a sine wave generation circuit 15, a PWM circuit 16, and an output circuit 17.

  The motor 11 includes a DC brushless motor having a permanent magnet in the rotor and a U-phase motor coil 4, a V-phase motor coil 5, and a W-phase motor coil 6 in the stator. In the motor 11, the rotor is driven to rotate when current flows through the U-phase motor coil 4, the V-phase motor coil 5, and the W-phase motor coil 6 according to the output of the output circuit 17.

  The three Hall sensors 1 to 3 correspond to the magnetic flux detection unit of the present invention, are provided corresponding to the permanent magnets of the rotor, and detect three-phase magnetic fluxes having a phase difference of about 120 ° with respect to each other. Each Hall sensor 1 to 3 outputs an H level or L level magnetic flux detection signal as shown in FIG. 2 (shown as Hall 1, Hall 2, and Hall 3 in FIG. 2).

  The rotor position detection circuit 13 detects the current sector of the rotor by a combination of H level or L level magnetic flux detection signals detected by the three Hall sensors 1 to 3. The current sector of the rotor means the sector in which the rotor is currently located among six sectors (one sector is an electrical angle of 60 °).

  The controller 14 corresponds to the control circuit of the present invention, and sequentially outputs an angle signal from the start point to the end point of the current sector of the rotor detected by the rotor position detection circuit 13 to the sine wave generation circuit 15 based on the rotation command. To do. The angle signal is a signal indicating a detailed angle included in the current sector. The start point and the end point are angles included in the current sector, and are arbitrarily set, for example, a minimum angle and a maximum angle included in the current sector. The rotation command is a signal for switching the rotation permission and the rotation prohibition of the motor 11.

  The sine wave generation circuit 15 is based on the angle signal output from the controller 14 and the H level or L level magnetic flux detection signals detected by the three Hall sensors 1, 2, 3 for each phase of the UVW phase. Then, a sine wave signal for driving the motor 11 in a sine wave is generated. As shown in FIG. 2, this sine wave signal is a sine wave duty signal U, duty V, and duty W each having a phase difference of approximately 120 °. In the example shown in FIG. 2, each signal of duty U, duty V, and duty W is on-duty.

  For each duty U, duty V, and duty W generated by the sine wave generation circuit 15, the PWM circuit 16 compares the duty with a triangular wave signal if it is an analog circuit, and compares it with a numerical value of an up / down counter if it is a digital circuit. Then, the PWM duty signal for the upper arm and the PWM duty signal for the lower arm are created.

  The output circuit 17 is configured by switching an upper arm power transistor (corresponding to the switching element of the present invention) and a lower arm power transistor (corresponding to the switching element of the present invention) in series for each phase of the UVW phase. A circuit (not shown). The PWM duty signal for the upper arm created by the PWM circuit 16 is applied to the base of the power transistor of the upper arm, and the created PWM duty for the lower arm is applied to the base of the power transistor of the lower arm. Thus, the upper arm power transistor and the lower arm power transistor are alternately turned on / off. In other words, the output circuit 17 corresponds to the motor drive unit of the present invention, performs PWM processing on the duty U, duty V, and duty W generated by the sine wave generation circuit 15, and drives the motor 11 by controlling power output. Let In the description, a power transistor is used, but a switching element such as an FET or IGBT may be used.

  When the transmission of the angle signal from the start point to the end point of the sector to the sine wave generation circuit 15 is completed, the controller 14 determines that the rotor is currently based on the magnetic flux detection signals of the Hall sensors 1 to 3 from the rotor position detection circuit 13. It is determined whether or not the sector has moved to the next sector.

  When it is determined that the controller 14 has not moved from the current sector to the next sector, the controller 14 again outputs an angle signal from the start point to the end point of the same sector to the sine wave generation circuit 15.

  When it is determined that the controller 14 has moved from the current sector to the next sector, the controller 14 outputs an angle signal corresponding to the next sector to the sine wave generation circuit 15.

  Next, the operation of the DC motor driving apparatus of the first embodiment configured as described above will be described in detail with reference to FIG. In the example shown in FIG. 3, the starting mechanism of the first embodiment when the outputs of the Hall sensors 1 to 3 have rotors at H, H, and L (sector (1) in FIG. 2) is shown.

  First, the rotor position detection circuit 13 detects the presence of a rotor in the sector (1) in FIG. 2 by combining the H level or L level magnetic flux detection signals detected by the three Hall sensors 1 to 3. .

  The controller 14 sequentially outputs an angle signal from the start point to the end point of the sector (1) in FIG. 2 to the sine wave generation circuit 15. Based on the angle signal from the controller 14, the sine wave generating circuit 15 generates the same waveform as the duty U in the sector of (1) in FIG. 2 at times t0 to t11. Similarly to the duty U, the waveforms of the duty V and the duty W are the same as the waveforms of (1) in FIG. Time t0 is the time when the duty corresponding to the start point of the sector is generated, and time t11 is the time when the duty corresponding to the end point of the sector is generated.

  However, at time t11, the output of the hall sensor 1 does not change from H to L. That is, the rotor has not moved from the current sector to the next sector. At this time, if the controller 14 determines that the rotor has not moved from the current sector to the next sector based on the magnetic flux detection signal from the rotor position detection circuit 13, the angle from the start point to the end point of the same sector again. The signal is output to the sine wave generation circuit 15.

  That is, the duty U is increased linearly at times t11 to t12 (time for one sector). Next, since the output of the Hall sensor 1 does not change from H to L also at time t12, the same waveform duty as that at times t0 to t11 is also generated from time t12 to t13.

  Furthermore, since the output of the Hall sensor 1 does not change from H to L at time t13, the same waveform duty as that at times t0 to t11 is generated at time t13.

  At time t1, the output of the hall sensor 1 changes from H to L. In other words, the sector of the rotor is switched by four retries, and the rotation of the motor 11 is detected. The controller 14 outputs an angle signal from the start point to the end point corresponding to the next sector to the sine wave generation circuit 15.

  For example, when the rotation of the motor 11 is detected at a time before reaching the time t11, the controller 14 may be configured to immediately start outputting an angle signal corresponding to the next sector.

  As described above, according to the DC motor driving apparatus of the first embodiment, the controller 14 outputs an angle signal corresponding to the same sector again when there is no movement of the rotor sector based on the magnetic flux detection signal from the rotor position detection circuit 13. To resume.

  That is, when excitation corresponding to a sine wave is performed from the start point to the end point of the current sector and the magnetic flux detection signal does not change in that sector, that is, when rotation of the rotor is not detected, the same sector angle signal is again used. By repeating excitation, sine wave driving can be performed.

  The DC motor driving apparatus according to the first embodiment can drive the motor 11 in a sine wave without using hardware such as an A / D converter for detecting detailed rotor position information. Therefore, it is possible to provide a DC motor driving device that can start a motor while maintaining quietness without causing a start failure due to sine wave driving with a simple configuration.

(Example 2)
FIG. 4 is a circuit configuration diagram of the DC motor driving apparatus according to the second embodiment. The DC motor driving apparatus according to the second embodiment shown in FIG. 4 further includes a rotational speed detection circuit 18, an adder 19, a proportional computing unit 20a, an integration, with respect to the configuration of the DC motor driving apparatus according to the first embodiment shown in FIG. A calculator 20b, a differential calculator 20c, and an adder 21 are provided.

  The rotation speed detection circuit 18 detects the current rotation speed of the rotor based on the H level or L level magnetic flux detection signals detected by the three Hall sensors 1 to 3.

  The adder 19 outputs the difference between the current rotational speed of the rotor detected by the rotational speed detection circuit 18 and the speed command to the proportional calculator 20a, the integral calculator 20b, and the differential calculator 20c.

  The proportional calculator 20a, the integral calculator 20b, and the differential calculator 20c correspond to the automatic control circuit of the present invention. The proportional calculator 20 a performs a proportional calculation (P calculation) on the difference between the rotation speed from the adder 19 and the speed command, and outputs a proportional calculation output to the adder 21. The integral calculator 20 b performs an integral calculation (I calculation) on the difference between the rotation speed from the adder 19 and the speed command, and outputs an integral calculation output to the adder 21. The differential calculator 20 c performs a differential calculation (D calculation) on the difference between the rotation speed from the adder 19 and the speed command, and outputs a differential calculation output to the adder 21. That is, PID calculation is performed.

  The adder 21 adds the proportional calculation output from the proportional calculation unit 20a, the integration calculation output from the integration calculation unit 20b, and the differential calculation output from the differentiation calculation unit 20c, and outputs the result to the controller 14 as a control output. The controller 14 determines the amplitude of the angle signal according to the control output from the adder 21.

  The control output becomes larger than the previous control output by the PID calculation. For this reason, since the amplitude of the angle signal is also larger than the amplitude of the previous angle signal by the PID calculation, the duty of each phase is also larger than the previous duty.

  FIG. 5 is a timing chart showing a three-phase hall sensor output waveform and a three-phase duty waveform when the DC motor driving apparatus according to the second embodiment is started. The start sequence shown in FIG. 5 is the second time that the amplitudes of the duties U, V, and W of the respective phases are larger than those in the first sequence (time t0 to t21) by PID calculation with respect to the start sequence shown in FIG. Sequence (time t21 to t22) is larger, and the third sequence (time t22 to t23) is larger than the second sequence (time t21 to t22).

  Therefore, a PWM duty that generates a larger torque can be obtained, and the motor 11 can be sine-wave driven more smoothly.

  The PID arithmetic circuit in the second embodiment is an example of the automatic control circuit of the present invention. A control operation circuit such as a PI operation circuit or an advanced control circuit for bringing the rotational speed of the rotor closer to the speed command can be applied to the automatic control circuit of the present invention.

(Example 3)
Even if each PWM duty is applied to the motor coil from the start point to the end point of the sector, the output of the Hall sensor may not be switched immediately. This is because the rotor must rotate by a maximum electrical angle of 60 ° in order to switch the output of the Hall sensor. In such a case, a standby operation may be inserted in the middle of waiting for a predetermined time to switch the Hall sensor output. The DC motor driving apparatus according to the third embodiment inserts a standby operation that waits for switching of the output of the Hall sensor on the way.

  FIG. 6 is a timing chart showing a three-phase Hall sensor output waveform and a three-phase duty waveform when the DC motor driving apparatus of Example 3 is started. In the example shown in FIG. 6, the duty U, V, W of each phase at time t0 to time t31 is the same as each duty at time t0 to time t11 in FIG. 3, but the duty of each phase from time t31 to time t32. U, V, and W hold predetermined values.

  That is, the duty U, V, W of each phase is held at a predetermined value for a predetermined time from the end point of the sector, and waits for the Hall sensor output to be switched. For this reason, the controller 14 sets the duty U, V, W of each phase to a predetermined value at the end point of the sector, and generates an angle signal for holding the predetermined value for a predetermined time from the end point of the sector.

  In this way, by maintaining a predetermined value for each duty for a predetermined time from the end point of the sector, when the output of the Hall sensor is switched during the standby operation, the same excitation can be repeated again by the angle signal of the same sector. Disappear.

Example 4
FIG. 7 is a timing chart showing a three-phase Hall sensor output waveform and a three-phase duty waveform when the DC motor driving apparatus of Example 4 is started. The DC motor drive device of the fourth embodiment shown in FIG. 7 combines the PID rotation speed control process shown in FIG. 5 and the process of inserting a standby operation for waiting for the change of the output of the hall sensor as shown in FIG. It is a thing.

  As described above, according to the DC motor driving apparatus of the fourth embodiment, the effects of the DC motor driving apparatus of the second embodiment and the effects of the DC motor driving apparatus of the third embodiment can be obtained.

  Note that the present invention is not limited to the DC motor driving devices of the first to fourth embodiments described above. In the first to fourth embodiments, the sinusoidal wave drive by PWM has been described as an example. However, for example, a linear amplifier system or a sinusoidal wave drive by another system can be realized.

  The present invention is applicable to a DC brushless motor.

1-3 Hall sensor 4 U phase motor coil 5 V phase motor coil 6 W phase motor coil 11 Motor 13 Rotor position detection circuit 14 Controller 15 Sine wave generation circuit 16 PWM circuit 17 Output circuit 18 Rotation speed detection circuit 19 Adder 20a Proportional Operation unit 20b Integration operation unit 20c Differentiation operation unit 21 Adder

Claims (6)

A magnetic flux detector that detects the magnetic flux of the rotor of the motor and outputs a magnetic flux detection signal;
A rotor position detection circuit for detecting a sector of the rotor based on the magnetic flux detection signal;
A control circuit that outputs an angle signal from the start point to the end point of the sector of the rotor and restarts the output of the angle signal of the same sector when there is no movement of the sector of the rotor based on the magnetic flux detection signal;
A sine wave generation circuit for generating a sine wave signal for driving the motor in a sine wave based on the angle signal;
A motor drive unit that creates a drive duty based on the sine wave signal and drives the motor by turning on / off a switching element by the drive duty;
Equipped with a,
A rotational speed detection circuit for detecting the rotational speed of the rotor based on the magnetic flux detection signal;
An automatic control circuit that performs a calculation based on the rotational speed and speed command of the rotor detected by the rotational speed detection circuit and outputs a control output to the control circuit;
The control circuit determines the amplitude of the angle signal according to the control output from the automatic control circuit, and when there is no movement of the sector of the rotor, the amplitude of the angle signal of the same sector is changed to the amplitude of the previous angle signal. DC motor drive device to be larger . 2. The DC motor driving apparatus according to claim 1 , wherein the control circuit generates an angle signal for setting the duty to a predetermined value at the end point of the sector and holding the predetermined value for a predetermined time from the end point of the sector. The rotor sector is in a range of predetermined electrical angles;
The starting point of the sector of the rotor is the smallest angle included in the range of the predetermined electrical angle;
3. The DC motor driving apparatus according to claim 1 , wherein an end point of the sector of the rotor is a maximum angle included in the range of the predetermined electrical angle. Wherein the control circuit, when the movement of the sectors of the rotor is detected, DC motor driving device according to any one of claims 1 to 3 and outputs an angle signal corresponding to the next sector. 5. The DC motor driving apparatus according to claim 4 , wherein when the movement of the sector of the rotor is detected, the control circuit immediately starts outputting an angle signal corresponding to the next sector. Detecting the rotor sector based on the magnetic flux of the rotor of the motor;
Outputting an angle signal from the start point to the end point of the sector of the rotor;
Generating a sinusoidal signal based on the angle signal;
Driving the motor based on the sine wave signal,
After the step of outputting the angle signal, if there is no movement of the sector of the rotor, the output of the angle signal of the same sector is restarted and the amplitude of the angle signal of the same sector is made larger than the amplitude of the previous angle signal. DC motor driving method.

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