TWI748906B - Driving device and control method of motor - Google Patents

Abstract

A driving device and a control method for a motor are provided. The control method includes: after a power up sequence of the motor, driving the motor according to a bipolar current driving scheme by a driver; detecting a black electro-motive force (BEMF) of the motor by a controller, and calculating rotating speed information and position information according to the BEMF; generating a judge result according to the rotating speed information and position information by the controller; and deciding whether to switch to drive the motor by a single current driving scheme.

Description

Motor drive device and control method thereof

The present invention relates to a motor driving device and a control method thereof, and more particularly to a motor driving device and a control method thereof that can improve the efficiency of electric energy use.

In the technical field of electric motors, there is a so-called sensorless permanent magnet brushless DC motor. Among them, when a sensorless permanent magnet brushless DC motor is performing a control action, it can calculate the motor's back electromotive force (Black ElectroMotive Force, BEMF) to know the motor's speed, position and other information, and it does not need to be set for detection. Detector for measuring speed and position.

In the conventional technology, in the control mechanism using the back electromotive force, an open-loop architecture is often used to perform control actions. Such an approach is prone to failure of the starting action, for example, the motor speed cannot be increased, and the phenomenon of lock-up occurs. The prior art also has a control mechanism that uses a closed-loop architecture to execute back-EMF. This method also consumes a large amount of electric energy during the start-up action, and even causes the motor speed to be unable to increase, and the phenomenon of lock-up occurs.

The invention provides a motor driving device and a control method thereof, which can improve the use efficiency of electric energy.

The control method of the motor of the present invention includes: after the power of the motor is started, the driver drives the motor according to the bipolar current driving mechanism; the controller detects the back electromotive force of the motor, and calculates the speed information of the motor based on the back electromotive force, and Position information; enable the controller to generate a judgment result based on the rotational speed information and the position information; and, according to the judgment result, determine whether to switch the driver to drive the motor according to a unipolar current drive mechanism.

The driving device of the motor of the present invention includes a driver and a controller. The driver has a plurality of switch groups, which respectively generate a plurality of driving voltages with different phases according to the plurality of control signals. The controller is coupled to the motor to enable the driver to drive the motor according to the bipolar current driving mechanism after the power of the motor is started; to calculate the back electromotive force of the motor according to a plurality of electrical parameters of the motor, and to calculate it according to the back electromotive force Output the speed information and position information of the motor; generate a judgment result based on the speed information and position information; and, according to the judgment result, determine whether to switch the driver to a unipolar current drive mechanism to drive the motor.

Based on the above, the motor driving device of the present invention sequentially drives the motor according to the bipolar current driving mechanism and the unipolar current driving mechanism, which effectively improves the electric energy use efficiency of the motor.

Please refer to FIG. 1. FIG. 1 is a schematic diagram of a motor driving device according to an embodiment of the present invention. The driving device 100 is used to drive the motor MT. The driving device 100 includes a controller 110 and a driver 120. The driver 120 has a plurality of switch groups formed by a plurality of transistors T11 to T32. Among them, the transistors T11 and T12 form a first switch group, and respectively generate a driving voltage U according to the control signals UGH and UGL; the transistors T21 and T22 form a second switch group, and are respectively controlled by the control signals VGH and VGL. A driving voltage V is generated; the transistors T31 and T32 form a third switch group, and the driving voltage W is generated according to the control signals WGH and WGL, respectively. The driving voltages U, V, and W may have different phases, for example, the phase difference of any two of the driving voltages U, V, and W is 120 ⁰ .

In terms of coupling details, the first terminal of the transistor T11 receives the power supply voltage BP, the second terminal of the transistor T11 is used to provide the driving voltage U, the control terminal of the transistor T11 receives the control signal UGH; the first terminal of the transistor T12 It is coupled to the second end of the transistor T11, the second end of the transistor T12 receives the reference ground voltage GND, and the control end of the transistor T12 receives the control signal UGL. The first terminal of the transistor T21 receives the power supply voltage BP, the second terminal of the transistor T21 is used to provide the driving voltage V, the control terminal of the transistor T21 receives the control signal VGH; the first terminal of the transistor T22 is coupled to the transistor The second end of T21 and the second end of transistor T22 receive the reference ground voltage GND, and the control end of transistor T22 receives the control signal VGL. In addition, the first terminal of the transistor T31 receives the power supply voltage BP, the second terminal of the transistor T31 is used to provide the driving voltage W, the control terminal of the transistor T31 receives the control signal WGH; the first terminal of the transistor T32 is coupled to The second end of the transistor T31 and the second end of the transistor T32 receive the reference ground voltage GND, and the control end of the transistor T32 receives the control signal WGL.

In this embodiment, the two transistors in the same transistor group (taking the transistors T11 and T12 as examples) can be turned on alternately to generate the corresponding driving voltage (for example, the driving voltage U). For example, when the transistor T11 is turned on according to the control signal UGH, the transistor T12 can be turned off according to the control signal UGL, and generates the driving voltage U equal to the power supply voltage BP through the turned on transistor T11. In contrast, when the transistor T11 is turned off according to the control signal UGH, the transistor T12 can be turned on according to the control signal UGL, and through the turned on transistor T12 to generate the driving voltage U equal to the reference ground voltage GND.

The driver 120 is coupled to the motor MT, and can respectively provide driving voltages U, V, and W to a plurality of windings of the stator of the motor MT (for example, composed of inductors L1 to L3), and thereby drive the motor MT.

On the other hand, the controller 110 is coupled to the driver 120 and the motor MT. The controller 110 can detect the driving voltages U, V, and W of the motor MT, and perform calculations based on the driving voltages U, V, and W to obtain the back electromotive force of the motor MT. The controller 110 may further calculate the rotational speed information and position information of the motor MT based on the back electromotive force of the motor MT. Then determine whether the rotation speed of the motor MT is equal to a preset rotation speed according to the rotation speed information of the judging motor MT, and/or determine whether the rotor of the motor MT is equal to a preset position according to the position information of the motor MT, to generate a judgment result.

According to the above judgment result, the controller 110 can generate the control signals UGH, UGL, VGH, VGL, WGH, and WGL so that the driver 120 can drive the motor MT by a bipolar current driving mechanism or a unipolar current driving mechanism.

Regarding the process of switching the driving mechanism performed by the controller 110, please refer to FIG. 1 and FIG. Wherein, in step S210, the power of the motor MT is turned on, and then, in step S220, the controller 110 can apply a bipolar current driving mechanism through the driver 120 to drive the motor MT to move. Here, the so-called bipolar current drive mechanism is to make two of the drive voltages U, V, and W received by the motor MT, in the same time interval, be periodic signals with opposite phases (for example, 18 Kilohertz square wave). Take, for example, that the driving voltages U and V are periodic signals with opposite phases. At this time, the two ends of the inductors L1 and L2 on the motor MT can induce currents in both positive and negative directions, and consume more power to make The motor MT executes the starting action.

During the operation of the motor MT, in step S230, the controller 110 can continuously monitor whether the motor MT and the driver 120 have overcurrent. When an overcurrent phenomenon occurs in one of the motor MT and the driver 120, the controller 110 can drive the driver 120 to perform step S260 to brake the motor to maintain the safety of the system. If neither the motor MT nor the driver 120 generates an overcurrent phenomenon, the controller 110 can continue to perform the operation of the motor MT.

On the other hand, the controller 110 can calculate the back electromotive force of the motor MT in real time, and calculate the rotational speed information and position information of the motor MT based on the back electromotive force. Next, in step S240, the controller 110 determines whether the rotation speed of the motor MT has reached a predetermined rotation speed (predetermined target), and/or determines whether the position of the motor MT has reached a predetermined position (predetermined target) based on the rotation speed information and the position information . When the rotation speed and/or position of the motor MT does not reach the predetermined target, the controller 110 returns to perform step S220 and causes the driver 120 to apply a bipolar current driving mechanism to drive the motor MT. In contrast, in step S240, when the rotation speed and/or position of the motor MT has reached the predetermined target, the controller 110 executes step S220 and causes the driver 120 to apply a unipolar current driving mechanism to drive the motor MT.

In the unipolar current driving mechanism, in the same time interval, the driver 120 can make one of the driving voltages U, V, W received by the motor MT a periodic signal (for example, a square wave of 18 kHz ), and make the other of the drive voltages U, V, W a DC signal. Under such a driving mechanism, taking the driving voltage U as a periodic signal and the driving voltage V as a DC voltage as an example, the two ends of the inductors L1 and L2 on the motor MT can induce a single-polarity current in a single direction, and consume more Less electric energy to keep the motor MT running.

It is worth mentioning that when the motor MT is disturbed by the external force and the rotation is not smooth, the controller 110 can know the state of the rotation of the motor MT according to the calculation of the back electromotive force, and make the driver 120 change according to step S220 , To drive the motor MT by applying a bipolar current drive mechanism.

According to the above description, in the method for controlling the motor MT according to the embodiment of the present invention, the controller 110 alternately applies the bipolar current driving mechanism and the unipolar current driving mechanism to drive the motor MT. Allows the motor MT to apply a bipolar current drive mechanism during the start-up phase (the phase of unstable speed), where the speed and/or position can quickly reach the expected target, and the motor MT is driven by a unipolar current while maintaining the stable rotation of the speed. Mechanism to save power consumption. In this way, the operating efficiency of the motor MT can be further improved.

Please refer to FIG. 1, FIG. 3A and FIG. 3B below. FIG. 3A shows a waveform diagram of the bipolar current driving mechanism of the motor driving device according to an embodiment of the present invention, and FIG. 3B shows the waveform diagram of the motor driving device according to an embodiment of the present invention. Waveform diagram of unipolar current drive mechanism. In FIG. 3A, under the bipolar current driving mechanism, the controller 110 can send control signals UGH, UGL, VGH, VGL, WGH, WGL to the driver 120 to control the transistors T11, T12, T21, T22, T31, and T32, respectively. The on or off state. Among them, in the time interval TP1, the controller 110 sends the control signals UGH and VGL as periodic signals (square wave signals) to make the transistors T11 and T22 periodically switch between the on and off states. Among them, based on the complementary phases of the control signals UGH and VGL, the conduction and cut-off states of the transistors T11 and T22 are opposite.

At the same time, the controller 110 sends control signals VGH, UGL, and WGL that are low voltages (for example, equal to the reference ground voltage GND) to make the transistors T12, T22, and T32 always turn off.

Corresponding to the above-mentioned on-off states of the transistors T11 to T32, the driver 120 can provide driving voltages U and V (see area Z1) as periodic signals during the time interval TP1, wherein the phases of the driving voltages U and V are complementary. Through the phase-complementary driving voltages U and V, the two ends of the inductors L1 and L2 on the motor MT can induce currents in both the positive and negative directions, and the motor MT can start the motor by consuming more power. action.

Incidentally, in the time interval TP1, the driving voltage W is a falling ramp signal.

In the time interval TP2 after the time interval TP1, the controller 110 generates the control signals UGH and WGL as periodic signals, and generates the control signals VGH, WGH, UGL, and VGL as low voltages (for example, equal to the reference ground voltage GND). In the time interval TP2, the driving voltages U and W are periodic signals with complementary phases, and the driving voltage V is a rising ramp signal. In the time interval TP3 after the time interval TP2, the controller 110 generates the control signals VGH and WGL as periodic signals, and generates the control signals VGL, WGH, UGL, and VGL as low voltages (for example, equal to the reference ground voltage GND). In the time interval TP3, the driving voltages V and W are periodic signals with complementary phases, and the driving voltage U is a falling ramp signal. In the time interval TP4 after the time interval TP3, the controller 110 generates the control signals VGH, UGL as periodic signals, and generates the control signals VGL, WGH, UGH, VGL as low voltages (for example, equal to the reference ground voltage GND). In the time interval TP4, the driving voltages V and U are periodic signals with complementary phases, and the driving voltage W is a rising ramp signal. In the time interval TP5 after the time interval TP4, the controller 110 generates the control signals WGH and UGL as periodic signals, and generates the control signals VGL, WGL, UGH, and VGL as low voltages (for example, equal to the reference ground voltage GND). In the time interval TP5, the driving voltages U and W are periodic signals with complementary phases, and the driving voltage V is a falling ramp signal. In the time interval TP6 after the time interval TP5, the controller 110 generates the control signals WGH and VGL as periodic signals, and generates the control signals VGL, WGL, UGH, and VGH as low voltages (for example, equal to the reference ground voltage GND). In the time interval TP6, the driving voltages V and W are periodic signals with complementary phases, and the driving voltage U is a rising ramp signal.

In the above description, each time interval TP1 ~ TP6, and account for the entire operation of the driver 120 to 1/6 cycle, i.e. a ⁶⁰⁰ phase. The time intervals TP7 and TP8 are the next operation cycle of the driver 120, and the details of the actions are the same as those in the time intervals TP1 and TP2, and will not be described in detail below.

In FIG. 3B, in the unipolar current driving mechanism, the controller 110 may send the control signal UGH as a periodic signal in the time interval TP1 to make the transistor T11 periodically turn on and off. At the same time, the controller 110 provides control signals VGH, WGH, UGL, WGL with low voltage (for example, reference ground voltage GND) in the time interval TP1, and provides control signal VGL with high voltage (for example, power supply voltage BP) to the driver 120, the transistors T12, T21, T31, and T32 are kept off, and the transistor T22 is kept on. In this way, the driver 120 can generate a driving voltage U that is a periodic signal (such as a square wave signal) and a driving voltage V that is maintained at a low voltage (such as the reference ground voltage GND) (such as the zone Z2). At this time, the two ends of the inductances L1 and L2 on the motor MT can induce a single-polarity current in a single direction, and consume less electric energy to keep the motor MT running. Incidentally, in the time interval TP1, the driving voltage W is a falling ramp signal.

In the time interval TP2 after the time interval TP1, the controller 110 provides a periodic signal control signal UGH to periodically turn on and turn off the transistor T11. The controller 110 further provides control signals VGH, WGH, UGL, VGL as low voltage (for example, reference ground voltage GND), and provides control signals WGL as high voltage (for example, the power supply voltage BP) to the driver 120, so that the transistors T12, T21, T31, and T22 are cut off, and the transistor T32 is turned on. In this way, the driver 120 can generate a driving voltage U that is a periodic signal (for example, a square wave signal) and a driving voltage W that is maintained at a low voltage (for example, the reference ground voltage GND). In the time interval TP2, the driving voltage V is a rising ramp signal.

In the time interval TP3 after the time interval TP2, the controller 110 provides a periodic signal control signal VGH to periodically turn on and turn off the transistor T21. The controller 110 provides control signals UGH, WGH, UGL, VGL with low voltage (for example, reference ground voltage GND), and provides control signal WGL with high voltage (for example, power supply voltage BP) to the driver 120 to make the transistors T12 and T21. , T31, T22 are cut off, and the transistor T32 is turned on. In this way, the driver 120 can generate a driving voltage V that is a periodic signal (for example, a square wave signal) and a driving voltage W that is maintained at a low voltage (for example, the reference ground voltage GND). In the time interval TP3, the driving voltage U is a falling ramp signal.

In the time interval TP4 after the time interval TP3, the controller 110 provides a periodic signal control signal VGH to turn the transistor T21 on and off periodically. The controller 110 provides the control signals UGH, WGH, WGL, VGL as low voltage (for example, reference ground voltage GND), and provides the control signal UGL as high voltage (for example, the power supply voltage BP) to the driver 120 to make the transistors T32 and T21. , T31, T22 are cut off, and the transistor T12 is turned on. In this way, the driver 120 can generate a driving voltage V that is a periodic signal (for example, a square wave signal) and a driving voltage U that is maintained at a low voltage (for example, the reference ground voltage GND). In the time interval TP4, the driving voltage W is a rising ramp signal.

In the time interval TP5 after the time interval TP4, the controller 110 provides a periodic signal control signal WGH to periodically turn on and turn off the transistor T31. The controller 110 provides the control signals UGH, VGH, WGL, VGL as low voltage (for example, reference ground voltage GND), and provides the control signal UGL as high voltage (for example, the power supply voltage BP) to the driver 120 to make the transistors T32 and T21. , T31, T22 are cut off, and the transistor T12 is turned on. In this way, the driver 120 can generate a driving voltage W that is a periodic signal (for example, a square wave signal) and a driving voltage U that is maintained at a low voltage (for example, the reference ground voltage GND). In the time interval TP5, the driving voltage V is a falling ramp signal.

In the time interval TP6 after the time interval TP5, the controller 110 provides a periodic signal control signal WGH to periodically turn on and turn off the transistor T31. The controller 110 provides control signals UGH, VGH, WGL, UGL with low voltage (for example, reference ground voltage GND), and provides control signal VGL with high voltage (for example, power supply voltage BP) to the driver 120, so that the transistors T32, T21 , T31, T12 are cut off, and the transistor T22 is turned on. In this way, the driver 120 can generate a driving voltage W that is a periodic signal (for example, a square wave signal) and a driving voltage V that is maintained at a low voltage (for example, the reference ground voltage GND). In the time interval TP6, the driving voltage U is a rising ramp signal.

In the embodiment of FIG. 3B, the details of the actions in the time intervals TP7 and TP8 are the same as the details of the actions in the time intervals TP1 and TP2, which will not be described in detail below.

Please refer to FIG. 4. FIG. 4 is a schematic diagram of an implementation of a controller of a motor driving device according to an embodiment of the present invention. The controller 400 includes a back electromotive force detection circuit 410, a protection detection circuit 420, a digital operation circuit 430, a control signal generator 440, and a reference signal generator 450. The back-EMF detection circuit 410 receives the driving voltages U, V, and W from the motor terminal, and performs calculations on the driving voltages U, V, and W to calculate the back-EMF of the motor. The protection detection circuit 420 is used to detect the over-current state of the motor, and perform a protection action when the motor generates an over-circuit state, such as causing the motor to perform a braking action. The protection detection circuit 420 can also be used to detect the over-voltage state, over-temperature state, or any other abnormal working state of the motor, and activate the protection mechanism or the warning mechanism accordingly.

The digital arithmetic circuit 430 can calculate the current rotation state of the motor according to the back electromotive force of the motor, and obtain speed information and/or position information according to it. The digital arithmetic circuit 430 can compare the target rotation speed and the target position based on the rotation speed information and/or the position information, and generate a comparison result. The digital arithmetic circuit 430 further controls the operation process of the motor according to the comparison result, so that the motor can work under the mechanism of bipolar driving current or unipolar driving current. The digital arithmetic circuit 430 can transmit information related to process control to the control signal generator 440, and the control signal generator 440 generates corresponding control signals UGH, UGL, WGH, WGL, VGH, VGL. The reference signal generator 450 is used to generate one or more reference signals to provide the reference values required by the back-EMF detection circuit 410, the protection detection circuit 420, the digital operation circuit 430, and the control signal generator 440 when performing operations. .

The controller 400 of the embodiment of the present invention can be constructed using digital circuits. The back electromotive force detection circuit 410, the protection detection circuit 420, the digital operation circuit 430, the control signal generator 440, and the reference signal generator 450 can all be digital The way of calculation to perform related actions. The hardware architecture of the back-EMF detection circuit 410, the protection detection circuit 420, the digital operation circuit 430, the control signal generator 440, and the reference signal generator 450 can be implemented using digital circuit design methods well known to those skilled in the art , Such as hardware description language, Karnaugh map, truth table and other methods, there is no fixed limit.

It is worth mentioning that the operation details of the back-EMF detection circuit 410 of this embodiment can be implemented by applying any algorithm for calculating the back-EMF of the motor well known to those skilled in the art, and there is no specific limitation.

In summary, the present invention enables the motor to dynamically switch between the bipolar current drive and the unipolar current drive mechanism according to the operating state of the motor, which can effectively improve the working efficiency of the motor.

100: Drive 110, 400: Controller 120: drive 410: Back-EMF detection circuit 420: protection detection circuit 430: Digital Operation Circuit 440: Control signal generator 450: Reference signal generator BP: power supply voltage GND: Reference ground voltage L1~L3: Inductance MT: Motor S210~S240: Control steps T11~T32: Transistor TP1~TP8: Time interval U, V, W: drive voltage UGH, UGL, VGH, VGL, WGH, WGL: control signal

FIG. 1 is a schematic diagram of a driving device of a motor according to an embodiment of the present invention. Fig. 2 shows an action flow chart of a motor control method according to an embodiment of the present invention. 3A is a waveform diagram of the bipolar current driving mechanism of the driving device of the motor according to the embodiment of the present invention. 3B is a waveform diagram of the unipolar current driving mechanism of the driving device of the motor according to the embodiment of the present invention. FIG. 4 is a schematic diagram of the implementation of the controller of the motor driving device according to the embodiment of the present invention.

100: Drive

110: Controller

120: drive

BP: power supply voltage

GND: Reference ground voltage

L1~L3: Inductance

MT: Motor

T11~T32: Transistor

U, V, W: drive voltage

UGH, UGL, VGH, VGL, WGH, WGL: control signal

Claims (15)

A method for controlling a motor includes: After the power of the motor is started, a driver is used to drive the motor according to a bipolar current driving mechanism; Enabling a controller to detect a back electromotive force of the motor, and calculate a rotational speed information and a position information of the motor based on the back electromotive force; Enabling the controller to generate a judgment result based on the rotational speed information and the position information; and According to the judgment result, it is determined whether to switch the driver to drive the motor according to a unipolar current driving mechanism. The control method according to claim 1, wherein the step of enabling the driver to drive the motor according to the bipolar current driving mechanism includes: Enabling the driver to provide a first driving voltage, a second driving voltage, and a third driving voltage with different phases to drive the motor, Wherein, in the bipolar current driving mechanism, in a first time interval, the first driving voltage and the second driving voltage have opposite polarities; in a second time interval, the first driving voltage and the second driving voltage The polarities of the three driving voltages are opposite; in a third time interval, the polarities of the second driving voltage and the third driving voltage are opposite. The control method according to claim 2, wherein under the unipolar current driving mechanism, in a fourth time interval, the first driving voltage is a periodic voltage, and the second driving voltage is a DC voltage; In a fifth time interval, the first driving voltage is the periodic voltage, the third driving voltage is the DC voltage; in a sixth time interval, the second driving voltage is the periodic voltage, the third The driving voltage is the DC voltage; in a seventh time interval, the second driving voltage is the periodic voltage, the first driving voltage is the DC voltage; in an eighth time interval, the second driving voltage is For the periodic voltage, the first driving voltage is the direct current voltage; in a ninth time interval, the third driving voltage is the periodic voltage, and the first driving voltage is the direct current voltage; and a tenth time interval Wherein, the third driving voltage is the periodic voltage, and the second driving voltage is the direct current voltage. The control method according to claim 2, wherein the phase difference between the first driving voltage, the second driving voltage, and the third driving voltage is 120 ⁰ . The control method according to claim 1, wherein the step of causing the controller to generate the judgment result according to the rotational speed information and the position information includes: The controller determines whether the rotation speed of the motor is equal to a preset rotation speed according to the rotation speed information, and determines whether the rotor position of the motor is equal to a preset position according to the position information to generate the judgment result. The control method according to claim 5, wherein the step of determining whether to switch the driver to drive the motor according to the unipolar current driving mechanism according to the judgment result includes: When the rotation speed of the motor is equal to the preset rotation speed and the rotor position of the motor is equal to the preset position, the driver is switched to drive the motor according to the unipolar current driving mechanism. The control method according to claim 6, wherein the step of determining whether to switch the driver to drive the motor according to the unipolar current driving mechanism according to the judgment result further comprises: When the rotation speed of the motor is not equal to the preset rotation speed and/or the rotor position of the motor is not equal to the preset position, the driver is maintained to drive the motor according to the bipolar current driving mechanism. The control method as described in claim 1, further including: Make the controller execute an over-current detection mechanism, and make the motor perform a braking procedure when an over-current phenomenon occurs. A driving device for a motor includes: A driver having a plurality of switch groups, respectively generating a plurality of driving voltages with different phases according to the plurality of control signals; and A controller, coupled to the motor, for: After the power of the motor is started, the driver is driven to drive the motor according to a bipolar current driving mechanism; Calculating a back electromotive force of the motor according to a plurality of electrical parameters of the motor, and calculating a rotational speed information and a position information of the motor according to the back electromotive force; Generate a judgment result based on the rotational speed information and the position information; and According to the judgment result, it is determined whether to switch the driver to drive the motor according to a unipolar current driving mechanism. The driving device according to claim 9, wherein the driver provides a first driving voltage, a second driving voltage, and a third driving voltage with different phases to drive the motor, and under the bipolar current driving mechanism, a In the first time interval, the first driving voltage and the second driving voltage have opposite polarities; in a second time interval, the first driving voltage and the third driving voltage have opposite polarities; and in a third time interval Wherein, the second driving voltage and the third driving voltage have opposite polarities. The driving device according to claim 10, wherein under the unipolar current driving mechanism, in a fourth time interval, the first driving voltage is a periodic voltage, and the second driving voltage is a DC voltage; In a fifth time interval, the first driving voltage is the periodic voltage, the third driving voltage is the DC voltage; in a sixth time interval, the second driving voltage is the periodic voltage, the third The driving voltage is the DC voltage; in a seventh time interval, the second driving voltage is the periodic voltage, the first driving voltage is the DC voltage; in an eighth time interval, the second driving voltage is For the periodic voltage, the first driving voltage is the direct current voltage; in a ninth time interval, the third driving voltage is the periodic voltage, and the first driving voltage is the direct current voltage; and a tenth time interval Wherein, the third driving voltage is the periodic voltage, and the second driving voltage is the direct current voltage. The driving device according to claim 9, wherein the controller determines whether the rotation speed of the motor is equal to a preset rotation speed according to the rotation speed information, and determines whether the rotor position of the motor is equal to a preset position according to the position information. The judgment result. The driving device according to claim 12, wherein when the rotation speed of the motor is equal to the preset rotation speed and the rotor position of the motor is equal to the preset position, the controller causes the driver to switch to drive the mechanism according to the unipolar current Drive the motor. The driving device according to claim 13, wherein when the rotation speed of the motor is not equal to the preset rotation speed and/or the rotor position of the motor is not equal to the preset position, the controller maintains the driver according to the bipolar Electric current drive mechanism to drive the motor. The driving device according to claim 9, wherein the controller is further used to implement an overcurrent detection mechanism, and when an overcurrent phenomenon occurs, the motor performs a braking procedure.

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