阅读说明：本技术 马达驱动电路及方法 (Motor driving circuit and method ) 是由 蔡明融 于 2019-09-24 设计创作，主要内容包括：本申请涉及马达驱动电路及方法。该马达驱动电路包括多个反相器电路、驱动信号查表模块、驱动信号产生部、工作周期命令侦测器及保护控制电路。多个反相器电路,各包括上桥开关及下桥开关。驱动信号查表模块对输入驱动信号进行查表,以产生驱动波形图样信号,同时输出正周期指示信号。驱动信号产生部响应于驱动波形图样信号以于每一相产生经脉冲调变的控制脉冲信号,以控制反相器电路的导通状态。工作周期命令侦测器在输入驱动信号对应的工作周期变化超过预定变化量时,产生第一保护启动信号。保护控制电路接收正周期指示信号,且在接收到第一保护启动信号时,于正周期区间输出强制关断信号以控制该些反相器电路的其中一相的下桥开关关断。(The present application relates to motor drive circuits and methods. The motor driving circuit comprises a plurality of inverter circuits, a driving signal look-up table module, a driving signal generating part, a duty cycle command detector and a protection control circuit. And a plurality of inverter circuits each including an upper bridge switch and a lower bridge switch. The driving signal table look-up module is used for looking up the input driving signal to generate a driving waveform pattern signal and outputting a positive period indicating signal. The driving signal generating section generates a pulse-modulated control pulse signal for each phase in response to the driving waveform pattern signal to control the on state of the inverter circuit. The duty command detector generates a first protection enable signal when a duty change corresponding to the input driving signal exceeds a predetermined variation. The protection control circuit receives the positive period indication signal, and outputs a forced turn-off signal in a positive period interval to control the turn-off of the lower bridge switch of one phase of the inverter circuits when receiving the first protection starting signal.)

1. A motor driver circuit, said motor driver circuit for driving a motor, said motor driver circuit comprising:

a plurality of inverter circuits respectively connected to the plurality of phase circuits of the motor, each of the inverter circuits including an upper bridge switch and a lower bridge switch;

a driving signal table look-up module for looking up a table of an input driving signal to generate a driving waveform pattern signal and outputting a positive period indicating signal which is used for indicating a positive period interval with the input driving signal;

a driving signal generating section configured to generate a pulse-modulated control pulse signal for each phase in response to the driving waveform pattern signal to control conduction states of the plurality of inverter circuits;

a duty cycle command detector configured to generate a first protection enable signal when a duty cycle variation corresponding to the input driving signal exceeds a predetermined variation; and

a protection control circuit configured to receive the positive period indication signal and output a forced turn-off signal in the positive period interval to control the lower bridge switch of one phase of the plurality of inverter circuits to turn off when receiving the first protection start signal.

2. The motor driving circuit of claim 1, further comprising a reverse current detection circuit disposed between the plurality of inverters and the plurality of phase circuits of the motor, the reverse current detection circuit being configured to output a second protection enable signal when detecting generation of a reverse current, wherein the protection control circuit is further configured to output the forced turn-off signal during the positive period to control turn-off of the lower bridge switch of one of the plurality of phase circuits when receiving the second protection enable signal.

3. The motor driving circuit as claimed in claim 2, wherein the reverse current detection circuit further comprises a first comparator configured to compare the reverse current with a reference current, and output the second protection enable signal if the reverse current is greater than the reference current.

4. The motor driving circuit of claim 1, wherein the protection control circuit comprises a counter configured to start timing when the forced turn-off signal is generated and stop outputting the forced turn-off signal after a predetermined time.

5. The motor drive circuit according to claim 1, wherein the drive signal generating section includes:

a sine wave modulator for receiving the driving waveform pattern signal to generate a sine wave modulation signal;

a triangular wave generator for generating a triangular wave signal; and

and the second comparator is used for receiving the sine wave modulation signal and the triangular wave signal and performing comparison operation to generate the control pulse signal.

6. The motor driving circuit as claimed in claim 5, wherein the driving signal generating portion further comprises a switching circuit and a square wave driving circuit, the switching circuit is configured to switch the output terminal of the driving signal generating portion from the output terminal of the second comparator to the square wave driving circuit when receiving the first protection signal, and the square wave driving circuit generates a plurality of square wave driving signals corresponding to a plurality of phase circuits of the motor according to the input driving signal to control the conducting states of the plurality of phase circuits.

7. A motor driving method, characterized by comprising the steps of:

configuring a driving signal table look-up module, performing table look-up on an input driving signal to generate a driving waveform pattern signal, and simultaneously outputting a positive period indicating signal for indicating a positive period interval with the input driving signal;

configuring a driving signal generating part for generating a pulse-modulated control pulse signal at each phase in response to an input driving signal to control the conduction states of a plurality of inverter circuits, wherein the plurality of inverter circuits are respectively connected to a plurality of phase circuits of a motor, and each inverter circuit comprises an upper bridge switch and a lower bridge switch;

configuring a duty cycle command detector to generate a first protection start signal when the duty cycle variation corresponding to the input driving signal exceeds a predetermined variation; and

and configuring a protection control circuit to receive the positive period indication signal, and when receiving the first protection starting signal, outputting a forced turn-off signal in the positive period interval to control the lower bridge switch of one phase of the inverter circuits to turn off.

8. The motor driving method as claimed in claim 7, further comprising configuring a reverse current detection circuit to output a second protection start signal when detecting reverse currents generated between the plurality of inverters and the plurality of phase circuits of the motor; and

the protection control circuit is configured to output the forced turn-off signal in the positive period interval to control the lower bridge switch of one phase of the inverter circuits to turn off when receiving the second protection starting signal.

9. The motor driving method as claimed in claim 8, further comprising configuring a first comparator of the reverse current detection circuit to compare the reverse current with a reference current, and outputting the second protection enable signal if the reverse current is greater than the reference current.

10. The motor driving method as claimed in claim 7, further comprising configuring a counter of the protection control circuit to start timing when the forced turn-off signal is generated and to stop outputting the forced turn-off signal after a predetermined time.

11. The motor driving method according to claim 7, further comprising:

a sine wave modulator of the driving signal generating part is configured to receive the driving waveform pattern signal and generate a sine wave modulation signal;

a triangular wave generator of the driving signal generating part is configured to generate a triangular wave signal; and

and configuring a second comparator to receive the sine wave modulation signal and the triangular wave signal and perform comparison operation to generate the control pulse signal.

12. The motor driving method as claimed in claim 11, further comprising a square wave driving circuit configuring a switching circuit of the driving signal generating section to switch an output terminal of the driving signal generating section from an output terminal of the second comparator to the driving signal generating section upon receiving the first protection signal; and

the square wave drive circuit is configured to generate a plurality of square wave drive signals corresponding to a plurality of phase circuits of the motor according to the input drive signal so as to control the conduction states of the phase circuits.

Technical Field

The present invention relates to a motor driving circuit and method, and more particularly, to a motor driving circuit and method for preventing reverse current from being generated when an output period is rapidly changed.

Background

In a motor such as a brushless dc motor which does not have a commutation mechanism formed of brushes, it is necessary to switch the direction of current supplied to the coils depending on the position of the rotor. The driving method of the brushless dc motor is roughly classified into the following two methods: a manner of using position information of the rotor obtained from the hall element; and a sensorless system for estimating the position of the rotor based on a zero-cross point of the back electromotive force (induced voltage) generated in the coil without using a hall element.

The existing direct current motor driving methods can be divided into a six-step square wave driving method and a sine wave pulse width modulation method, and the two different driving methods have advantages and disadvantages respectively. The sine wave pulse width modulation driving method is similar to an alternating current motor, three-phase sine wave current is input at a stator end to generate a set of rotating magnetic field to drive a rotor to rotate, and the brushless direct current motor is driven by the sine wave pulse width modulation driving method to obtain smaller torque ripple, but a position sensor with higher resolution is required to generate correct sine wave signals. The six-step square wave driving method has the advantages of low switching loss, no need of precise rotor position feedback, and the like, but has larger torque ripple.

Secondly, when the motor rotation speed is controlled, the pulse width modulation technology is mainly used, namely, a pulse width modulation signal is generated to control the transistor switch, and the work period of the pulse width modulation signal is in direct proportion to the average voltage given to the motor, so that the rotation speed of the motor can be further controlled. The pwm signal controls the transistor switches in many different ways, such as by alternately or simultaneously controlling the upper bridge transistor switch and the lower bridge transistor switch.

However, when the rotation speed of the motor is controlled to decrease, the back electromotive force generated when the rotor of the motor is still in a high-speed operation state due to inertia will generate a reverse current, and the generated reverse current will flow back to the power source end in a positive period and when the lower bridge transistor switch is turned off, the voltage of the voltage source will be increased, and the component will be damaged.

Therefore, a motor driving circuit and method capable of preventing the generation of a reverse current when the output period is rapidly changed is urgently needed.

Disclosure of Invention

The present invention is directed to a motor driving circuit and a method thereof, which can prevent a reverse current from being generated when an output period is rapidly changed.

In order to solve the above technical problem, one technical solution of the present invention is to provide a motor driving circuit for driving a motor, the motor driving circuit including: a plurality of inverter circuits respectively connected to the plurality of phase circuits of the motor, each of the inverter circuits including an upper bridge switch and a lower bridge switch; a driving signal table look-up module for looking up a table of an input driving signal to generate a driving waveform pattern signal and outputting a positive period indicating signal which is used for indicating a positive period interval with the input driving signal; a driving signal generating section configured to generate a pulse-modulated control pulse signal for each phase in response to the driving waveform pattern signal to control conduction states of the plurality of inverter circuits; a duty cycle command detector configured to generate a first protection enable signal when a duty cycle variation corresponding to the input driving signal exceeds a predetermined variation; and a protection control circuit configured to receive the positive period indication signal and output a forced turn-off signal in the positive period interval to control the lower bridge switch of one phase of the plurality of inverter circuits to turn off when receiving the first protection start signal.

Preferably, the motor driving circuit further includes a reverse current detection circuit disposed between the plurality of inverters and the plurality of phase circuits of the motor, the reverse current detection circuit being configured to output a second protection enable signal when detecting generation of a reverse current, wherein the protection control circuit is further configured to output the forced turn-off signal in the positive period to control turn-off of the lower bridge switch of one of the plurality of phase circuits when receiving the second protection enable signal.

Preferably, the reverse current detection circuit further comprises a first comparator configured to compare the reverse current with a reference current, and output the second protection enable signal if the reverse current is greater than the reference current.

Preferably, the protection control circuit includes a counter configured to start timing when the forced turn-off signal is generated and stop outputting the forced turn-off signal after a predetermined time.

Preferably, the driving signal generating part includes: a sine wave modulator for receiving the driving waveform pattern signal to generate a sine wave modulation signal; a triangular wave generator for generating a triangular wave signal; and a second comparator for receiving the sine wave modulation signal and the triangular wave signal and performing a comparison operation to generate the control pulse signal.

Preferably, the driving signal generating portion further includes a switching circuit and a square wave driving circuit, the switching circuit is configured to switch the output terminal of the driving signal generating portion from the output terminal of the comparator to the square wave driving circuit when receiving the first protection signal, and the square wave driving circuit generates a plurality of square wave driving signals corresponding to a plurality of phase circuits of the motor according to the input driving signal to control the on-state of the plurality of phase circuits.

In order to solve the above technical problem, another technical solution of the present invention is to provide a motor driving method, including the steps of: configuring a driving signal table look-up module, performing table look-up on an input driving signal to generate a driving waveform pattern signal, and simultaneously outputting a positive period indicating signal for indicating a positive period interval with the input driving signal; configuring a driving signal generating part for generating a pulse-modulated control pulse signal at each phase in response to an input driving signal to control the on-state of a plurality of inverter circuits, wherein the plurality of inverter circuits are respectively connected to a plurality of phase circuits of a motor, each of which includes an upper bridge switch and a lower bridge switch; configuring a duty cycle command detector to generate a first protection start signal when the duty cycle variation corresponding to the input driving signal exceeds a predetermined variation; and configuring a protection control circuit to receive the positive period indication signal, and when receiving the first protection starting signal, outputting a forced turn-off signal in the positive period interval to control the lower bridge switch of one phase of the inverter circuits to turn off.

Preferably, the motor driving method further includes configuring a reverse current detection circuit to output a second protection start signal when detecting that reverse currents are generated between the plurality of inverters and the plurality of phase circuits of the motor; and configuring the protection control circuit to output the forced turn-off signal in the positive period interval to control the lower bridge switch of one phase of the inverter circuits to turn off when receiving the second protection starting signal.

Preferably, the motor driving method further includes configuring a first comparator of the reverse current detection circuit to compare the reverse current with a reference current, and outputting the second protection start signal if the reverse current is greater than the reference current.

Preferably, the motor driving method further includes configuring a counter of the protection control circuit to start timing when the forced turn-off signal is generated, and to stop outputting the forced turn-off signal after a predetermined time.

Preferably, the motor driving method further includes: a sine wave modulator of the driving signal generating part is configured to receive the driving waveform pattern signal and generate a sine wave modulation signal; a triangular wave generator of the driving signal generating part is configured to generate a triangular wave signal; and configuring a second comparator to receive the sine wave modulation signal and the triangular wave signal and perform a comparison operation to generate the control pulse signal.

Preferably, the motor driving method further includes a square wave driving circuit configuring a switching circuit of the driving signal generating section to switch an output terminal of the driving signal generating section from an output terminal of the comparator to the driving signal generating section upon receiving the first protection signal; and configuring the square wave drive circuit to generate a plurality of square wave drive signals corresponding to a plurality of phase circuits of the motor according to the input drive signal so as to control the conduction states of the phase circuits.

The motor driving circuit and the motor driving method provided by the invention have the advantages that when the output period or the input command is rapidly switched, the reverse current can be prevented, the triggering condition of the protection mechanism can be adjusted, the triggering condition threshold is reduced in the application with larger back electromotive force, and on the contrary, the threshold can be increased, so that the applicability is increased.

In addition, the motor driving circuit and the method provided by the invention can further adjust the time for continuous protection after triggering, and increase the time for continuous protection triggering in the application with larger back electromotive force by properly selecting the triggering condition, otherwise, the time can be reduced to increase the applicability.

For a better understanding of the features and technical content of the present invention, reference should be made to the following detailed description of the invention and accompanying drawings, which are provided for purposes of illustration and description only and are not intended to limit the invention.

Drawings

Fig. 1 is a circuit architecture diagram of a motor driving circuit according to an embodiment of the present invention.

Fig. 2 is a circuit architecture diagram of the motor and inverter circuits.

Fig. 3 is another circuit architecture diagram of the motor driving circuit according to the embodiment of the invention.

FIG. 4 is a timing diagram of the motor driving circuit according to the embodiment of the present invention.

Fig. 5 is a schematic diagram of six-step square wave control switching.

Fig. 6 is a flowchart of a motor driving method according to an embodiment of the invention.

Detailed Description

The following description is provided for the embodiments of the motor driving circuit and method disclosed in the present application with reference to specific embodiments, and those skilled in the art will understand the advantages and effects of the present application from the disclosure of the present application. The invention is capable of other and different embodiments and its several details are capable of modification and various other changes, which can be made in various details within the specification and without departing from the spirit and scope of the invention. The drawings of the present invention are for illustrative purposes only and are not intended to be drawn to scale. The following embodiments will further explain the related art of the present invention in detail, but the disclosure is not intended to limit the scope of the present invention.

It will be understood that, although the terms "first," "second," "third," etc. may be used herein to describe various components or signals, these components or signals should not be limited by these terms. These terms are used primarily to distinguish one element from another element or from one signal to another signal. In addition, the term "or" as used herein should be taken to include any one or combination of more of the associated listed items as the case may be.

Fig. 1 is a circuit architecture diagram of a motor driving circuit according to an embodiment of the present invention. Referring to fig. 1, the embodiment of the invention provides a motor driving circuit 1 for driving a motor 11, wherein the motor driving circuit 1 includes a plurality of inverter circuits 10, a driving signal generating portion 12, a driving signal look-up table module 14, a duty command detector 16 and a protection control circuit 18.

Fig. 2 is a circuit architecture diagram of the motor and inverter circuits. Referring to fig. 2, the inverter circuits 10u, 10v and 10w are respectively connected to a plurality of phase circuits U, V, W of the motor, and each of the inverter circuits includes an upper bridge switch M1, M2 and M3, and a lower bridge switch M4, M5 and M6. The drive signal generating unit 12 receives an input drive signal, and outputs control pulse signals UH, UL, VH, VL, WH, and WL to control the on/off states of the respective switching units in the inverter circuit 18.

Generally, the motor 11 has three windings, i.e., a U-coil winding, a V-coil winding, and a W-coil winding. As can be seen from the circuit structure of fig. 2, the inverter circuit 10 includes upper bridge switches M1, M2, M3 and lower bridge switches M4, M5, M6, when the upper bridge switch M1 and the lower bridge switch M5 are turned on, the current for operating the motor flows from the power source terminal to the ground terminal through the transistor M1, the U-coil winding and the V-coil winding of the motor 12, and then through the transistor M5.

In general, normal motor current control is performed in such a manner that a U coil winding flows to a V coil winding, the U coil winding flows to a W coil winding, then commutation flows to the W coil winding from the U coil winding, commutation current flows to the W coil winding from the V coil winding, then the V coil winding flows to the U coil winding, and the V coil winding flows to the W coil winding. Then, the other commutation continues to control the current flow direction of the U-coil winding, the V-coil winding, and the W-coil winding, and further control the direction of rotation of the motor.

The driving signal look-up table module 14 is configured to perform a look-up table on the input driving signal IN to generate a driving waveform pattern signal IN', and output a positive period indication signal for indicating a positive period interval of the input driving signal. The driving signal lut 14 can be a database, a register, a memory or other components with storage functions, which are only exemplary and not limiting.

IN detail, the input signal IN may include a commutation signal obtained from a rotor position detector (e.g., a hall sensor) or by using a back emf detection mechanism. On the other hand, the driving signal lut 14 may be used to query the built driving waveform pattern data for the input signal IN, for example, third-order harmonic waveforms (third-order harmonics) or sinusoidal waves are generally used to generate a driving waveform image signal IN 'for driving the motor, and the driving waveform pattern signal IN' is sequentially sent out corresponding waveform patterns according to the input signal IN, for example, a commutation signal obtained by the rotor position detector or by using a back electromotive force detection mechanism.

Further, the driving signal generating section 12, IN response to the driving waveform pattern signal IN', is configured to generate pulse-modulated control pulse signals UH, UL, VH, VL, WH, WL for each phase to control the on-states of the inverter circuits 10u, 10v, and 10 w.

The duty cycle command detector 16 is configured to generate a first protection enable signal when a duty cycle variation corresponding to the input driving signal exceeds a predetermined variation. For example, when the input driving signal controls the rotation speed of the motor 11 to decrease, and the back electromotive force generated when the rotor of the motor 11 is continuously in the high-speed operation state due to inertia will generate a back current, and the generated back current will flow back to the power source end when the pull-down transistor switch is turned off in the positive period, and will increase the voltage potential of the voltage source, thereby damaging the components.

The protection control circuit 18 is configured to receive the positive period indication signal and output a forced turn-off signal during the positive period to control the inverter circuit, such as the lower bridge switch M4 of the inverter circuit 10u, to turn off during the positive period when receiving the first protection enable signal, thereby preventing generation of reverse current and preventing component damage.

Fig. 3 is another circuit architecture diagram of the motor driving circuit according to the embodiment of the invention. In detail, the motor driving circuit 1 may include a reverse current detection circuit 13 disposed between the inverter circuit 10 and the phase circuit of the motor 11, configured to output a second protection start signal when detecting generation of a reverse current, wherein the protection control circuit 18 is further configured to output a forced turn-off signal in a positive period interval to control turn-off of the lower bridge switch of one phase of the inverter circuit 10 when receiving the second protection start signal.

In the present embodiment, the reverse current detecting circuit 13 further includes a first comparator CP1 configured to compare the currents Iv, Iu and Iw between the inverter circuit 10 and the phase circuit of the motor 11 with the reference current IREF, and output a second protection enable signal if the currents Iv, Iu and Iw are greater than the reference current IREF.

In the present embodiment, the protection control circuit 18 includes a counter 180 configured to start timing when the forced shutdown signal is generated and stop outputting the forced shutdown signal after a predetermined time T1.

The driving signal generating unit 12 further includes a sine wave modulator 120, a triangular wave generator 122, and a second comparator CP 2. The sine wave modulator 120 is configured to receive the driving waveform pattern signal IN' generated by the driving signal lut 14 to generate the sine wave modulation signal HS, the triangular wave generator 122 is configured to generate the triangular wave signal TS, and the second comparator CP2 is configured to receive the sine wave modulation signal HS and the triangular wave signal TS and perform a comparison operation to generate the control pulse signal Pu/Pv/Pw.

Fig. 4 is a signal timing diagram of a motor driving circuit according to an embodiment of the invention. IN the time interval Ta, the sine wave modulator 120 is configured to receive the driving waveform pattern signal IN' generated by the driving signal look-up table module 14 to generate a sine wave modulation signal HS, the triangular wave generator 122 is configured to generate a triangular wave signal TS, the second comparator CP2 is configured to receive the sine wave modulation signal HS and the triangular wave signal TS and perform a comparison operation to generate a control pulse signal Pu/Pv/Pw, where the control pulse signal Pu/Pv/Pw can be respectively used as a control pulse signal UH, UL, VH, VL, WH, WL, and controls the conduction states of the inverter circuits 10u, 10v, and 10w, and further controls the operation of the motor 11.

When the time interval Tb is entered, the input driving signal IN reduces the rotation speed of the motor 11 from 100% to 60%, for example, and the driving signal look-up table module 14 performs look-up table on the input driving signal IN to output a positive period indication signal for indicating the positive period interval TP of the driving waveform pattern corresponding to the driving waveform pattern signal IN'. The duty command detector 16 generates a first protection enable signal when detecting that the duty cycle variation corresponding to the input driving signal IN exceeds a predetermined variation, and the protection control circuit 18 is configured to receive the positive cycle indication signal and output a forced turn-off signal Soff1 IN the positive cycle interval TP to control the inverter circuit, such as the lower bridge switch M4 of the inverter circuit 10u, to turn off, thereby preventing generation of a reverse current and preventing component damage. In the application with larger back electromotive force, the condition triggered by the protection mechanism can be adjusted, for example, the triggering condition threshold is lowered, and conversely, the threshold can be increased to increase the applicability.

In addition, the counter 180 starts timing when generating the forced turn-off signal Soff1, stops outputting the forced turn-off signal Soff1 after a predetermined time T1, and the user can adjust the time for continuous protection after triggering according to the requirement, and increase the time for triggering continuous protection in the application with large back electromotive force by properly selecting the triggering condition, otherwise, the time can be reduced to increase the applicability.

On the other hand, the currents Iv, Iu and Iw between the inverter circuit 10 and the phase circuit of the motor 11 may also be compared with the reference current IREF by the first comparator CP1 of the reverse current detection circuit 13, if the currents Iv, Iu and Iw are greater than the reference current IREF, a second protection start signal is output, and the protection control circuit 18 may output the forced turn-off signal Soff2 in the positive period TP to control the lower bridge switch of one phase of the inverter circuit 10 to turn off when receiving the second protection start signal. At this time, the counter 180 starts counting when the forced off signal Soff2 is generated, and stops outputting the forced off signal Soff2 after a predetermined time T2.

Referring to fig. 3, the driving signal generating portion 12 further includes a switching circuit 124 and a square wave driving circuit 126. When receiving the first protection signal, the switching circuit 124 switches the output terminal of the driving signal generating unit 12 from the output terminal of the second comparator CP2 to the square wave driving circuit 126, and the square wave driving circuit can generate a plurality of square wave driving signals corresponding to the phase circuit U, V, W of the motor 11 according to the input driving signal IN to control the on state of the phase circuit U, V, W.

Referring to fig. 5, a schematic diagram of six-step square wave control switching can be seen. As shown in the figure, taking the pulse signals UH and UL as an example, since the lower bridge switch M4 is controlled by the pulse signal UL, it can be known that the lower bridge switch M4 is kept in the off state in the positive period TP, and therefore, similarly, the generation of the reverse current can be avoided, and the device damage can be further prevented. Although the switching to the six-step square wave driving method causes a large torque ripple, it also has the advantages of low switching loss and no need of precise rotor position feedback.

Fig. 6 is a flowchart of a motor driving method according to an embodiment of the invention. Referring to fig. 6, an embodiment of the invention provides a motor driving method, which is applied to the motor driving circuit 1 in the foregoing embodiment, and includes at least the following steps:

step S100: and the driving signal table look-up module is configured to look-up the input driving signal to generate a driving waveform pattern signal and output a positive period indication signal. The positive period indication signal indicates a positive period interval of the input driving signal.

Step S102: the driving signal generating part is configured to respond to the driving waveform pattern signal and generate a pulse-modulated control pulse signal in each phase so as to control the conduction state of the plurality of phase circuits. The inverter circuits are respectively connected to a plurality of phase circuits of the motor, and each phase circuit comprises an upper bridge switch and a lower bridge switch.

Step S104: the configuration duty cycle command detector generates a first protection enable signal when a duty cycle variation corresponding to the input driving signal exceeds a predetermined variation.

Step S106: the configuration protection control circuit receives the positive period indication signal and outputs a forced turn-off signal in a positive period interval to control the turn-off of the lower bridge switch of one phase of the inverter circuits when receiving a first protection starting signal.

The motor driving method of the present invention includes the operation of each component of the motor driving circuit in the foregoing embodiments, and therefore, the details are not described herein.

Advantageous effects of the embodiments

The motor driving circuit and the motor driving method provided by the invention have the advantages that when the output period or the input command is rapidly switched, the reverse current can be prevented, the triggering condition of the protection mechanism can be adjusted, the triggering condition threshold is reduced in the application with larger back electromotive force, and on the contrary, the threshold can be increased, so that the applicability is increased.

Furthermore, the motor driving circuit and the method provided by the invention can further adjust the time for continuous protection after triggering, and increase the time for continuous protection triggering in the application with larger back electromotive force by properly selecting the triggering condition, and conversely, can reduce the time to increase the applicability.

The disclosure is only a preferred embodiment of the invention, and is not intended to limit the scope of the claims, so that all technical equivalents and modifications using the contents of the specification and drawings are included in the scope of the claims.