阅读说明：本技术 马达控制方法与装置 (Motor control method and device ) 是由 陈锦豪 李正中 孟育民 于 2019-01-08 设计创作，主要内容包括：一种马达控制方法与装置,该马达控制方法适用于无传感器的直流无刷马达的启动程序。此马达控制方法包括下列步骤。依据具有第一预设值的启动电流信号及相电流信号,产生相电压信号与驱动电压信号。依据驱动电压信号产生驱动电流信号,以驱动变频器控制直流无刷马达进行运转,其中第一预设值用于至少使直流无刷马达维持正常运转。感测驱动电流信号,以产生对应的相电流信号。依据随对应的相电流信号变化的相电压信号与启动电流,确定直流无刷马达的轴端负载状态。依据负载状态及/或依据直流无刷马达的电气旋转角速度与扭力需求,适应性调整启动电流信号的大小。(A motor control method and device are provided, which are suitable for the starting procedure of a sensorless DC brushless motor. The motor control method includes the following steps. And generating a phase voltage signal and a driving voltage signal according to the starting current signal and the phase current signal with the first preset value. And generating a driving current signal according to the driving voltage signal to drive the frequency converter to control the DC brushless motor to operate, wherein the first preset value is used for at least keeping the DC brushless motor to operate normally. The driving current signal is sensed to generate a corresponding phase current signal. And determining the shaft end load state of the direct current brushless motor according to the phase voltage signal and the starting current which are changed along with the corresponding phase current signal. The magnitude of the starting current signal is adaptively adjusted according to the load state and/or according to the electrical rotation angular velocity and the torque force requirement of the DC brushless motor.)

1. A motor control method is suitable for a starting program of a direct current brushless motor, and is characterized by comprising the following steps:

(a) generating a phase voltage signal and a driving voltage signal according to a starting current signal and a phase current signal with a first preset value;

(b) generating a driving current signal according to the driving voltage signal to drive a DC brushless motor to operate, wherein the first preset value is used for at least keeping the DC brushless motor to operate normally;

(c) sensing the driving current signal to generate a corresponding phase current signal;

(d) determining a load state of an axial end of the direct current brushless motor according to the phase voltage signal and the starting current signal which are changed along with the corresponding phase current signal; and

(e) and adaptively adjusting the magnitude of the starting current signal according to the shaft end load state and/or according to an electrical rotation angular velocity and a torque requirement of the direct current brushless motor.

2. The motor control method of claim 1, wherein the phase voltage signals include at least one of d-axis voltage signals and q-axis voltage signals.

3. The motor control method according to claim 1, wherein the step (e) includes:

according to the load state, the starting current signal is adjusted from the first preset value to a second preset value.

4. The motor control method of claim 3, wherein the step (e) further comprises:

when the electrical rotation angular velocity of the dc brushless motor reaches a preset angular velocity and is maintained at the preset angular velocity, the start current signal is adjusted from the second preset value to a third preset value according to the torque requirement of the dc brushless motor.

5. The motor control method according to claim 1, wherein the step (e) includes:

when the electrical rotation angular velocity of the dc brushless motor reaches a preset angular velocity and is maintained at the preset angular velocity, the start current signal is adjusted from the first preset value to a second preset value according to the torque requirement of the dc brushless motor.

6. The motor control method of claim 5, wherein the step (e) further comprises:

and regulating the starting current signal from the second preset value to a third preset value according to the load state.

7. The motor control method according to claim 1, wherein the step (e) includes:

when the load state is a locked-rotor state, the starting current signal is increased from the first preset value to a second preset value, wherein the maximum value of the second preset value is a maximum current allowed by the DC brushless motor.

8. The motor control method according to claim 1, wherein the step (d) includes:

carrying out low-pass filtering and integral amplification processing on the phase voltage signal to generate a processed phase voltage signal; and

and determining the load state of the DC brushless motor according to the processed phase voltage signal and the processed starting current signal.

9. The method of claim 1, wherein the first predetermined value is set according to the phase voltage signal obtained by the DC brushless motor during a previous start-up procedure.

10. A motor control device adapted to a starting process of a dc brushless motor, the motor control device comprising:

the driving unit generates a phase voltage signal and a driving voltage signal according to a starting current signal and a phase current signal with a first preset value;

a frequency converter, generating a driving current signal according to the driving voltage signal to drive a DC brushless motor to operate, wherein the first preset value is used for at least keeping the DC brushless motor operating normally;

a sensing unit for sensing the driving current signal of the frequency converter to generate a corresponding phase current signal; and

and the control unit is used for providing the starting current signal, determining the shaft end load state of the direct current brushless motor according to the phase voltage signal and the starting current signal which are changed along with the corresponding phase current signal, and adaptively adjusting the size of the starting current signal according to the shaft end load state and/or according to an electrical rotation angular velocity and a torque requirement of the direct current brushless motor.

11. The motor control apparatus of claim 10 wherein the phase voltage signals comprise at least one of d-axis voltage signals and q-axis voltage signals.

12. The apparatus of claim 10, wherein the control unit further adjusts the start-up current signal from the first predetermined value to a second predetermined value according to the load condition.

13. The apparatus of claim 12, wherein the control unit decreases the start current signal from the second predetermined value to a third predetermined value according to the torque requirement of the dc brushless motor when the electrical angular velocity of the dc brushless motor reaches and is maintained at a predetermined angular velocity.

14. The apparatus of claim 10, wherein the control unit further adjusts the start current signal from the first predetermined value to a second predetermined value according to the torque requirement of the DC brushless motor when the electrical angular velocity of the DC brushless motor reaches a predetermined angular velocity and is maintained at the predetermined angular velocity.

15. The apparatus of claim 14, wherein the control unit further adjusts the start-up current signal from the second predetermined value to a third predetermined value according to the load condition.

16. The apparatus of claim 10, wherein the control unit further increases the start current signal from the first predetermined value to a second predetermined value when the load condition is a locked-rotor condition, wherein a maximum value of the second predetermined value is a maximum current allowed by the dc brushless motor.

17. The apparatus of claim 10, wherein the control unit further performs a low pass filtering and integral amplification process on the phase voltage signal, and determines the load status of the dc brushless motor according to the processed phase voltage signal and the start current signal.

18. The apparatus of claim 10, wherein the first predetermined value is set according to the phase voltage signal obtained by the dc brushless motor during a previous start-up procedure.

Technical Field

The present invention relates to a control method and device, and more particularly, to a motor control method and device suitable for a starting procedure of a sensorless dc brushless motor.

Background

The current methods for obtaining the rotor position of a brushless DC motor are mainly divided into two methods, i.e., a sensor (encoder) method and a sensorless (electrical estimation) method, and in the case of applications with lower requirements on speed and position control performance or poor environmental conditions, a sensorless driving technique is mostly used as a method for controlling the rotor position obtained by the brushless DC motor.

The conventional sensorless driving technique generally requires that the motor is controlled to a certain rotation speed by an open-loop current or voltage, and then enters a closed-loop control after the sensorless algorithm detects the position information of the motor rotor. However, since the rotor load condition cannot be estimated in the open-loop current or voltage control, a large current is mostly applied to drive the motor to prevent the motor from failing to start. Such a large current will cause excessive power loss under light load conditions. Therefore, there is still room for improvement in the design of the start control of the motor.

Disclosure of Invention

The present invention provides a motor control method and device, so as to effectively reduce the electric quantity loss of the motor during the start control.

The invention provides a motor control method, which is suitable for a starting program of a sensorless direct current brushless motor. The motor control method includes the following steps. And generating a phase voltage signal and a driving voltage signal according to the starting current signal and the phase current signal with the first preset value. And generating a driving current signal according to the driving voltage signal to drive the DC brushless motor to operate, wherein the first preset value is used for at least keeping the DC brushless motor to operate normally. The driving current signal is sensed to generate a corresponding phase current signal. And determining the shaft end load state of the direct current brushless motor according to the phase voltage signal and the starting current signal which are changed along with the corresponding phase current signal. And the magnitude of the starting current signal is adaptively adjusted according to the load state of the shaft end and/or according to the electric rotation angular velocity and the torque force requirement of the direct current brushless motor.

The invention also provides a motor control device, which comprises a driving unit, a frequency converter, a sensing unit and a control unit. The driving unit generates a phase voltage signal and a driving voltage signal according to a starting current signal and a phase current signal with a first preset value. The frequency converter generates a driving current signal according to the driving voltage signal to drive the DC brushless motor to operate, wherein the first preset value is used for at least keeping the DC brushless motor to operate normally. The sensing unit senses a driving current signal of the frequency converter to generate a corresponding phase current signal. The control unit provides a starting current signal, determines the shaft end load state of the direct current brushless motor according to the phase voltage signal and the starting current signal which change along with the corresponding phase current signal, and adaptively adjusts the size of the starting current signal according to the shaft end load state and/or the electric rotation angular velocity and the torque force requirement of the direct current brushless motor.

The motor control method and device disclosed by the invention can adaptively adjust the magnitude of the starting current signal according to the shaft end load state and/or according to the electric rotation angular velocity and the torque force requirement of the direct current brushless motor. Therefore, the situation that the electric quantity loss is increased because the DC brushless motor is driven to operate by the continuous large starting current can be avoided, and the electric quantity loss of the DC brushless motor in the starting procedure can be effectively reduced.

Drawings

Fig. 1A is a schematic diagram of a motor control apparatus according to an embodiment of the invention.

Fig. 1B is a single-phase equivalent circuit of a dc brushless motor according to an embodiment of the invention.

Fig. 1C is a vector analysis of a single-phase equivalent circuit of a dc brushless motor according to an embodiment of the invention.

Fig. 1D is a vector analysis of a single-phase equivalent circuit of a dc brushless motor according to another embodiment of the present invention.

FIG. 1E is a vector analysis of the output voltage of the frequency converter in the d-q axis according to one embodiment of the present invention.

FIG. 1F is a vector analysis of the output voltage of a frequency converter according to another embodiment of the present invention on the d-q axis.

FIG. 1G is a vector analysis of the output voltage of a frequency converter according to another embodiment of the present invention on the d-q axis.

FIG. 1H is a vector analysis of the output voltage of a frequency converter according to another embodiment of the present invention on the d-q axis.

Fig. 2 is a timing diagram illustrating the operation of the motor control apparatus according to an embodiment of the present invention.

Fig. 3 is a timing chart illustrating the operation of a motor control apparatus according to another embodiment of the present invention.

Fig. 4 is a timing chart illustrating the operation of a motor control apparatus according to another embodiment of the present invention.

Fig. 5 is a flowchart of a motor control method according to an embodiment of the invention.

Fig. 6 is a flowchart of a motor control method according to another embodiment of the invention.

Fig. 7 is a flowchart of a motor control method according to another embodiment of the invention.

Fig. 8 is a flowchart of a motor control method according to another embodiment of the present invention.

Fig. 9 is a flowchart of a motor control method according to another embodiment of the invention.

Wherein the reference numerals are:

100: motor control device

110: drive unit

111: speed generator

112: subtracter

113: speed controller

114. 122, 123: limiting device

115: speed and position estimator

116: counter electromotive force estimator

117. 118: switching device

119: three-phase to two-phase converter

120. 121: current controller

124: two-phase to three-phase converter

125: modulation unit

130: frequency converter

140: sensing unit

150: control unit

160: DC brushless motor

i_qs: starting current signal

v_ds、v_qs: phase voltage signal

W_set: angular velocity

_ω: error of angular velocity

v_{emf_α}、v_{emf_β}: back electromotive force voltage

θ_r: electrical angle

v_α、v_β: static shaft voltage

i_α、i_β: current of static shaft

Current signal

i′_as、i′_bs、i′_cs: phase current signal

i′_ds、i′_qs: current of synchronous shaft

Electric current

v_u、v_v、v_w: three-phase voltage

T: during a start-up procedure

W1: electrical angular velocity of rotation

S1: rotational speed

T1, T2, T3, T4: period of time

S11, S12: curve line

i 1: first preset value

i 2: second preset value

i 3: third preset value

500. 600, 700, 800, 900: motor control method

S502 to S510, S608, S610, S710, S712, S810, S812, S910: step (ii) of

Detailed Description

In each of the embodiments listed below, the same or similar components or elements will be denoted by the same reference numerals.

Fig. 1A is a schematic diagram of a motor control apparatus according to an embodiment of the invention. Referring to fig. 1A, the motor control apparatus 100 of the present embodiment is suitable for a start-up procedure of the sensorless dc brushless motor 160. In other words, the motor control device 100 does not include a position sensor-related line. In the control circuit of the motor with the sensor, the position sensor is mounted on the motor. In some embodiments, the dc brushless motor 160 may be applied to home appliances, such as a drum washing machine, a vertical washing machine, a dryer/dryer, and the like, but is not limited thereto. In the present embodiment, the motor control apparatus 100 includes a driving unit 110, a frequency converter 130, a sensing unit 140 and a control unit 150.

The driving unit 110 generates a d-axis voltage signal v according to the starting current signal iqs and the phase current signal_dsAnd q-axis voltage signal v_qsAnd according to the d-axis voltage signal v_dsAnd q-axis voltage signal v_qsAnd generating a driving voltage signal.

Specifically, at the initial stage of driving the dc brushless motor 160 (when t is 0), the driving unit 110 receives a start current signal i given a first preset value (which may be adjusted according to actual conditions)_qsD-axis current signal with zero sum current valueTo generate a d-axis voltage signal v_dsAnd q-axis voltage signal v_qsAnd further generates an initial driving voltage signal.

In some embodiments, the first preset value is used to at least maintain the dc brushless motor 160 in normal operation, and the effective value (root-mean-square) of the first preset value is, for example, 4A (amperes). In the present embodiment, the starting current signal iqs is, for example, a q-axis current for driving the dc brushless motor 160.

The inverter 130 generates driving current signals (i.e., three-phase current signals ias, ibs, ics) according to the driving voltage signal to drive the dc brushless motor 160 to operate. Since the starting current signal iqs has the first predetermined value at the initial stage to enable the inverter 130 to generate a sufficient driving current signal, the motor 160 can start to operate at the initial stage.

The sensing unit 140 is coupled to the output terminal of the frequency converter 130, and is used for sensing the driving current signals (e.g. at least two of the three-phase current signals ias, ibs, ics) of the frequency converter 130 to generate phase current signals (i'_as、i′_bs、i′_cs) And feeds back the generated phase current signal to the driving unit 110, so that the driving unit 100 generates a d-axis voltage signal v that changes in response to the phase current signal_dsAnd q-axis voltage signal v_qs。

The control unit 150 is coupled to the driving unit 110, and is used for providing a starting current signal iqs to the driving unit 110, and according to a d-axis voltage signal v varying with the phase current signal generated by the sensing unit_dsAnd the starting current signal iqs, the shaft end load state of the dc brushless motor 160 is judged. Then, the control unit 150 adaptively adjusts the magnitude of the starting current signal iqs provided to the driving unit 110 according to the shaft end load state and/or according to the electrical rotation angular velocity and torque requirement of the dc brushless motor 160. The shaft end load conditions include, but are not limited to, light load (light load), medium load (middle load), and Heavy load (Heavy load). In addition, the electrical rotation angular velocity of the dc brushless motor 160 can be known from the internal digital information of the controller 150.

Specifically, in the initial stage, the driving unit 110 receives the d-axis current command signal having a current value of zero (i.e., the d-axis current command signal)) And the control unit 150 provides the starting current signal iqs with a first preset value, and generates a starting current signal iqs according to the starting current signal iqsd-axis voltage signal v_dsAnd q-axis voltage signal v_qsTo generate corresponding driving current signals to drive the dc brushless motor 160. Then, the sensing unit 160 senses a driving current signal required by the initial operation of the dc brushless motor 160 to generate a corresponding phase current signal, and feeds the phase current signal back to the driving unit 110. The driving unit 110 correspondingly adjusts the d-axis voltage signal v according to the phase current signal generated by the sensing unit 140_dsAnd q-axis voltage signal v_qsAt this time, the control unit 150 may adjust the d-axis voltage signal v according to the adjusted d-axis voltage signal_dsThe shaft end load status of the dc brushless motor 160 is determined (i.e., the motor 160 is determined to be under light load, under medium load, or under heavy load). Then, the control unit 150 can adaptively adjust the magnitude of the starting current signal iqs provided to the driving unit 110 according to the shaft end load state and/or according to the electrical rotation angular velocity and torque requirement of the dc brushless motor 160. Further, if the motor 160 is determined to be under light load, the control unit 150 may reduce the provided starting current signal iqs without continuously providing the starting current signal iqs with the first initial value, so as to reduce power consumption required for initially driving the motor.

In some embodiments, as shown in fig. 1A, the driving unit 110 includes a speed command generator 111, a subtractor 112, a speed controller 113, a limiter 114, a speed and position estimator 115, a back electromotive force estimator 116, a switch 117, a switch 118, a three-to-two phase converter 119, a current controller 120, a current controller 121, a limiter 122, a limiter 123, a two-to-three phase converter 124, and a modulation unit 125, which is not limited thereto.

The speed command generator 111 is used to generate an angular speed command. The subtractor 112 is for subtracting the angular velocity from the angular velocity command of the velocity command generator 111To obtain the angular velocity error_ω. The speed controller 113 is connected to the subtractor 112, receives the angular speed error and adjusts the angular speed according to the received angular speed error_ωTo generate a current signal. The limiter 114 is connected to the speed controller 113, and receives and limits the current signal generated by the speed controller 113. Speed andthe position estimator 115 is connected to the subtractor 112 and receives the back electromotive voltage v_{emf_α}、v_{emf_β}To produce angular velocityAt an electrical angleThe back EMF estimator 116 is coupled to the speed and position estimator 115 and receives the stationary shaft voltage v_α、v_βAnd stationary shaft current i_α、i_βTo generate a back electromotive voltage v_{emf_α}、v_{emf_β}。

The switch 117 is connected to the limiter 114 and the control unit 120, receives the current signal generated by the speed controller 113 and the start current signal iqs generated by the control unit 150, and selects the current signal generated by the speed controller 113 or the start current signal iqs generated by the control unit 150 to output a current signalIn the present embodiment, in the open-loop control mode, the switch 117 selects the starting current signal iqs generated by the control unit 150 to output a current signalIn the closed-loop control mode, the switch 117 selects the current signal generated by the speed controller 113 to output the current signal

The switch 118 connects the speed and position estimator 115 with the control unit 150, receives the electrical angle generated by the speed and position estimator 115And the electrical angle generated by the control unit 150To transportElectrical angle theta_r. In the present embodiment, in the open-loop control mode, the switch 118 selects the electrical angle generated by the control unit 150To output an electrical angle theta_r. In the closed loop control mode, the switch 118 selects the speed and position estimator 115 electrical angleTo output an electrical angle theta_r。

A three-to-two phase converter 119 connected to the sensing unit 140, the back electromotive force estimator 116 and the switch 118 receives the phase current signal i'_as、i′_bs、i′_csAt an electrical angle theta_rFirstly, the phase current signal i'_as、i′_bs、i′_csStatic shaft current i converted into two phases_α、i_βThen the two-phase static shaft current i is applied_α、i_βSynchronous shaft current i 'converted into two phases'_ds、i′_qs. Current controller 120 is coupled to three-to-two phase converter 119 and receives synchronous shaft current i'_dsAnd currentTo generate a synchronous shaft voltage. Current controller 121 is connected to three-to-two phase converter 119 and receives synchronous shaft current i'_qsAnd currentTo generate a synchronous shaft voltage. The current controllers 120 and 121 are proportional-integral (PI) controllers, respectively.

The limiter 122 is connected to the current controller 120, and limits the synchronous shaft voltage generated by the current controller 120 to generate a synchronous shaft d-axis voltage signal v_ds. The limiter 123 is connected to the current controller 121 for limiting the synchronous shaft voltage generated by the current controller 121 to generate a synchronous shaft q-axis voltage signal v_qs。

Two-phase to three-phase converter 124 are connected to the limiters 122, 123, the bemf estimator 116 and the switch 118, and receive the synchronization axis d-axis voltage signal v_dsQ-axis voltage signal v of synchronous axis_qsAt an electrical angle theta_rFirstly, a d-axis voltage signal v of the synchronous shaft is obtained_dsWith the q-axis voltage signal v of the synchronisation axis_qsInto a stationary shaft voltage v_αAnd stationary shaft voltage v_βThen the static shaft voltage v is applied_αAnd stationary shaft voltage v_βConversion to three-phase voltage v_u、v_v、v_w. The modulation unit 125 is connected to the two-phase to three-phase converter for receiving the three-phase voltage v_u、v_v、v_wAnd for three-phase voltage v_u、v_v、v_wPerforms pulse width modulation to generate a driving voltage signal of pulse width modulation voltage to the frequency converter 130.

Fig. 1B is a single-phase equivalent circuit of a dc brushless motor according to an embodiment of the invention. Fig. 1C is a vector analysis of a single-phase equivalent circuit of a dc brushless motor according to an embodiment of the invention. Fig. 1D is a vector analysis of a single-phase equivalent circuit of a dc brushless motor according to another embodiment of the present invention. Please refer to FIG. 1B, FIG. 1C and FIG. 1D, v_unIs a phase voltage i_unFor phase current, v_rsIs the voltage, v, of the internal resistor rs of the DC brushless motor 160_LIs the voltage, v, of the internal inductor L of the DC brushless motor 160_{un_EMF}Is a back electromotive voltage, v_{z_un}Is the impedance voltage v of the DC brushless motor 160_rsAnd v_LThe vector sum of (1).

The output mechanical power of the dc brushless motor 160 is expressed by the following equation (1):

P_m＝ω_m·T_e， (1)

wherein, P_mIs the output mechanical power of the DC brushless motor 160, omega_mIs angular velocity, T_eIs the output torque of the dc brushless motor 160, which is dependent on the load conditions experienced by the rotor shaft ends of the dc brushless motor 160 while the speed of the dc brushless motor 160 is maintained. When the shaft end load of the dc brushless motor 160 increases, the torque T of the dc brushless motor 160_eWill also increaseAdditionally, the mechanical power of the dc brushless motor 160 is increased by the requirement of maintaining the constant speed of the dc brushless motor 160.

In addition, the electrical input power of the dc brushless motor 160 can be expressed by the following equation (2):

wherein, P_eProportional to the mechanical output power of the rotor shaft end of the DC brushless motor 160, with "3" being three-phase, v_{un_EMF}Is a back electromotive voltage i_unFor phase current, θ₁Is a back electromotive force voltage v_{un_EMF}Phase current i_unAngle between v and v_unIs a phase voltage of θ₂Is a phase voltage v_unPhase current i_unThe included angle therebetween. Further, the relationship between the mechanical output power and the electrical input power of the dc brushless motor 160 is as shown in the following equation (3):

P_m＝P_e·η， (3)

wherein η represents the efficiency of the DC brushless motor 160, in addition, the relative relationship between the voltage and the current component of the equation (2) under the condition of light load and heavy load of the DC brushless motor 160 can be respectively shown in FIG. 1C and FIG. 1D, wherein FIG. 1C corresponds to the corresponding relationship between the voltage and the current component under the condition of heavy load of the DC brushless motor 160, and FIG. 1D corresponds to the corresponding relationship between the voltage and the current component under the condition of light load of the DC brushless motor 160, that is, it can be known from FIG. 1C and FIG. 1D that, when the phase current i is_unPhase voltage v while maintaining a fixed value_unThe magnitude and phase of the phase change with the increase of the output mechanical power (i.e. the axial end load value of the motor) of the dc brushless motor 160, especially the phase current i_unAnd phase voltage v_unThe included angle of (a) clearly reflects the shaft end load characteristic of the dc brushless motor 160, that is, the mechanical output power of the dc brushless motor 160 increases due to the increase of the shaft end load, and the shaft end load characteristic of the dc brushless motor 160 can also be observed from the electrical input power of the dc brushless motor 160.

In short, when starting upThe stage of the motor 160 is to provide a constant driving current (e.g., constant i)_un) To start the motor 160, the characteristics of the shaft end load of the motor 160 (e.g., heavy load or light load) can be reversed by sensing the mechanical power of the motor 160. After the characteristics of the load are known, the driving current provided can be correspondingly adjusted according to the characteristics of the load.

FIG. 1E is a vector analysis of the output voltage of the frequency converter in the d-q axis according to one embodiment of the present invention. FIG. 1F is a vector analysis of the output voltage of a frequency converter according to another embodiment of the present invention on the d-q axis. FIG. 1G is a vector analysis of the output voltage of a frequency converter according to another embodiment of the present invention on the d-q axis. FIG. 1H is a vector analysis of the output voltage of a frequency converter according to another embodiment of the present invention on the d-q axis. Wherein FIG. 1E corresponds to FIG. 1F and FIG. 1G corresponds to FIG. 1H. In some embodiments, the output voltage of the frequency converter 130 can be obtained through a hardware detection circuit or by a digital control command of software).

In FIGS. 1E, 1F, 1G and 1H, v_sAs a three-phase voltage vector v_un、v_vn、v_wnSum, v_dsIs a voltage signal of d-axis, v_qsIs the q-axis voltage signal. Fig. 1E and 1F correspond to the correspondence relationship between the voltage and the current component when the dc brushless motor 160 is heavily loaded, and fig. 1G and 1H correspond to the correspondence relationship between the voltage and the current component when the dc brushless motor 160 is lightly loaded. As can be seen from fig. 1E, 1F, 1G and 1H, when the load at the shaft end of the dc brushless motor 160 increases, the d-axis voltage signal v_ds(|v_ds|＝|v_s·sinθ₂I) will decrease (as shown in fig. 1E and 1F), and when the load at the shaft end of the dc brushless motor 160 decreases, the d-axis voltage signal v_dsWill rise (as shown in fig. 1G, 1H). That is, by observing the d-axis voltage signal v_dsThe shaft end load condition of the dc brushless motor 160 can be known.

In some embodiments, the control unit 150 may first couple the d-axis voltage signal v_dsLow pass filtering and integral amplifying to obtain processed productd-axis voltage signal v_dsAnd according to the processed d-axis voltage signal v_dsAnd a starting current signal i_qsThe shaft end load state of the dc brushless motor 160 is determined.

In addition, in the above-described embodiment, the control unit 150 uses the d-axis voltage signal v_dsAnd a starting current signal i_qsThe shaft end load state of the dc brushless motor 160 is determined, but the present invention is not limited thereto, and the control unit 150 may use the q-axis voltage signal v_qsAnd a starting current signal i_qsThe shaft end load state of the dc brushless motor 160 is determined. In some embodiments, the control unit 150 may also use the d-axis voltage signal v at the same time_dsAnd q-axis voltage signal v_qsAnd a starting current signal i_qsThe shaft end load state of the dc brushless motor 160 is determined.

Then, the control unit 150 electrically rotates the angular velocity according to the internal parameterAnd obtains the torque requirement of the dc brushless motor 160 under different angular velocities and angular accelerations according to the formula (4) (as shown below),

T_e＝T_L+J dω/dt+Bω (4)

wherein, T_eTorque output by the motor, i.e. torque requirement to maintain the motor at a specific angular velocity and a specific angular acceleration, T_LThe load torque borne by the shaft end of the dc brushless motor 160 is J, the rotor inertia, ω, the angular velocity, and B, the friction. The control unit 150 obtains the electrical rotation angular velocity of the DC brushless motorAnd calculated T_eAfter the torque demand, the control unit 150 adaptively adjusts the starting current signal i of the driving unit 110 according to the current torque demand state of the dc brushless motor 160_qsE.g. to activate the current signal i_qsThe size of the key is adjusted and reduced. Therefore, during the starting procedure of the dc brushless motor 160, the number of the dc brushless motors can be effectively reducedUp to 160 power loss.

While the components of the motor control apparatus 100 of the present embodiment and the arrangement thereof have been described above, other embodiments will be listed below to describe the operation of the motor control apparatus 100.

Fig. 2 is a timing diagram illustrating the operation of the motor control apparatus according to an embodiment of the present invention. Referring to FIG. 2, the symbol T denotes a start-up procedure period, i.e., an open-loop control phase, and the start-up procedure period T includes periods T1, T2, T3 and T4. The curve S11 represents the phase current for driving the DC brushless motor 160, and the curve S12 represents the predicted shaft end load condition of the DC brushless motor 160 according to the present invention, i_qsTo activate the current signal (corresponding to the peak value of the phase current of the dc brushless motor 160), W1 is the actual value corresponding to the command for the electrical rotational angular velocity supplied to the dc brushless motor 160, and the value is set to T1 to T4 during the period T1 to T4The remaining period is the angular velocity command generated by the velocity command generator 111, and S1 is the actual rotation speed of the dc brushless motor 160.

During the period T1, the control unit 150 provides a start current signal i_qsAnd will start the current signal i_qsIncreasing to the first preset value i 1. In addition, the driving unit 110 is based on the starting current signal i with the first preset value i1_qsThe phase current signal generates a driving voltage signal corresponding to the phase current signal and provides the driving voltage signal to the inverter 130, so that the inverter 130 generates a driving current signal according to the driving voltage signal to drive the dc brushless motor 160 to operate.

During the period T2, analyzing the actual shaft end load status of the dc brushless motor 160 as the above principle would be reflected in the output d-axis voltage signal v of the current controllers 120 and 121_dsAnd q-axis voltage signal v_qsAccordingly, the control unit 150 can apply the d-axis voltage signal v_dsOr q-axis voltage signal v_qsProcessing (e.g., low pass filtering and integral amplification processing) is performed to obtain the classification information (e.g., curve S12 of fig. 2) of the shaft end load status of the dc brushless motor 160, wherein the classification information may be, for example, light load, medium load or heavy load.

In term ofAt time T3, the control unit 150 will start the current signal i according to the shaft end load status of the DC brushless motor (i.e. the shaft end load information provided by the curve S12)_qsThe value is adjusted from the first preset value i1 to the second preset value i2, and the slope of the adjustment is Δ 1, for example. The effective value (root mean square) of the second preset value i2 is, for example, 3A. The effective value (root mean square) of the first preset value is, for example, 4A. The second preset value i2 can be changed according to the different shaft end load conditions. For example, the second default value i2 for the light load is smaller than the second default value i2 for the medium load, and the second default value i2 for the medium load is smaller than the second default value i2 for the heavy load.

During the period T4, when the value W1 corresponding to the electrical angular velocity command supplied to the dc brushless motor 160 reaches and is maintained at the preset angular velocity Wset, and the dc brushless motor 160 rotates synchronously, that is, when the dc brushless motor 160 rotates synchronouslyThe motor speed is also maintained at a constant value. At this time, since the rotation speed of the dc brushless motor 160 is kept constant, J d ω/dt in equation (4) is zeroed, and the friction force B corresponding to the dc brushless motor 160 decreases as the rotation speed of the dc brushless motor 160 increases (the friction force decreases), so the control unit 150 can obtain the torque requirement corresponding to the dc brushless motor 160 through equation (4) or a look-up table, that is, the torque requirement of the dc brushless motor 160 decreases.

Then, the control unit 150 can send the start current signal i according to the torque requirement of the dc brushless motor 160_qsIs adjusted to the third preset value i3 from the second preset value i2, and the slope of the adjustment is Δ 2, for example. The effective value (root mean square) of the third preset value i3 is, for example, 2A. Similarly, the third preset value i3 will also vary with the second preset value i 2.

Fig. 3 is a timing chart illustrating the operation of a motor control apparatus according to another embodiment of the present invention. In FIG. 3, during the T periods T1 and T2 of the start-up procedure period T, the start-up current signal i_qsThe electrical rotational angular velocity W1 of the dc brushless motor 160 is substantially the same as that of fig. 2. The difference between fig. 3 and fig. 2 is that after the period T2When the electrical rotational angular velocity W1 of the dc brushless motor 160 reaches the preset angular velocity Wset and is maintained at the preset angular velocity Wset, the rotational speed of the dc brushless motor 160 is also maintained constant at period T3.

At this time, since the rotation speed of the dc brushless motor 160 is kept constant, J d ω/dt in equation (2) is zero, and the friction force B corresponding to the dc brushless motor 160 decreases as the rotation speed of the dc brushless motor 160 increases (the friction force decreases), so the control unit 150 can obtain the torque requirement corresponding to the dc brushless motor 160 through equation (4) or look-up table, that is, the torque requirement of the dc brushless motor 160 decreases. Then, the control unit 150 can send the start current signal i according to the torque requirement of the dc brushless motor 160_qsThe effective value of the first preset value i1, which is adjusted to the second preset value i2, is, for example, 3A, and the slope of the adjustment is, for example, Δ 2.

Then, during the period T4, the control unit 150 activates the current signal i according to the shaft end load status of the dc brushless motor (e.g., curve S12 of fig. 2)_qsIs adjusted to the third preset value i3 from the second preset value i2, and the slope of the adjustment is Δ 1, for example. . The effective value of the third preset value i3 is, for example, 2A. Similarly, the third preset value i3 will also vary according to the shaft end load condition. For example, the third default value i3 for the light load is smaller than the third default value i3 for the medium load, and the third default value i3 for the medium load is smaller than the third default value i3 for the heavy load.

Fig. 4 is a timing chart illustrating the operation of a motor control apparatus according to another embodiment of the present invention. In FIG. 4, during the T periods T1 and T2 of the start-up procedure period T, the start-up current signal i_qsThe cyclonic rotational angular velocity W1 of the dc brushless motor 160 is substantially the same as that of fig. 2 and 3. The difference between FIG. 4 and FIGS. 2 and 3 is that the control unit 150 does not assert the enable current signal i during a period T3 after the period T2_qsMaking adjustments, i.e. the starting current signal i_qsStill maintained at the first preset value i 1.

Next, during a period T4, when the electrical rotational angular velocity W1 of the dc brushless motor 160 reaches the preset angular velocity Wset and is maintained at the preset angular velocity Wset, the dc brushless motor 160 is operatedThe rotational speed of up to 160 remains fixed. Since the rotation speed of the dc brushless motor 160 is kept constant and the torque requirement of the dc brushless motor 160 calculated by the control unit 150 is decreased, the control unit 150 can send the start current signal i according to the torque requirement of the dc brushless motor 160 and the shaft end load status of the dc brushless motor 160_qsIs adjusted to a second preset value i2 from the first preset value i 1. The effective value of the second preset value i2 is, for example, 2A. The second preset value i2 is also adjusted according to the different shaft end load conditions.

In some embodiments, the control unit 150 generates the d-axis voltage signal v according to the time periods T2-T4 shown in FIG. 2, FIG. 3, and FIG. 4_dsAnd q-axis voltage signal v_qsDetermines the shaft end load state of the dc brushless motor 160, and determines whether the shaft end load state is a locked-rotor state. When the load state of the shaft end is determined to be the locked-rotor state, the control unit 150 further sends a starting current signal i_qsThe first, second and third preset values i1, i2, i3 are adjusted to the fourth preset value i4, so that the dc brushless motor 160 can operate smoothly. The fourth preset value i4 is, for example, the maximum current allowed by the dc brushless motor 160, and the effective value of the maximum current is, for example, 5A. In the present embodiment, the starting current signal i_qsThe adjustment method of (1) is to adjust the first preset value i1 to the fourth preset value i4 according to a rising slope, and the value of the slope is not limited.

As described in the foregoing embodiments, during the starting procedure of the dc brushless motor 160, the motor control apparatus 100 of the present embodiment can adaptively decrease the magnitude of the starting current signal according to the shaft end load condition, the electrical rotation angular velocity and the torque requirement of the dc brushless motor 160. Therefore, the situation that the power loss is increased by driving the dc brushless motor 160 with a continuously large starting current signal can be avoided, so as to effectively reduce the power loss of the dc brushless motor 160 during the starting procedure.

In the foregoing embodiment, the motor control device 100 is suitable for driving the dc brushless motor 160, and particularly, the dc brushless motor 160 without a sensor, but the present invention is not limited thereto. The Motor control apparatus 100 of the present embodiment may also be adapted to drive an Interior Permanent Magnet Synchronous Motor (IPMSM), and the operation of the Motor control apparatus 100 can still achieve the same control effect with reference to the description of the above embodiments.

In addition, the first preset value is a preset example, but the invention is not limited thereto. If the difference between the starting loads of the dc brushless motor 160 is not large, the first preset value can be obtained according to the d-axis voltage signal v obtained during the previous starting procedure period T_dsAnd q-axis voltage signal v_qsIs set by the control unit 150.

Fig. 5 is a flowchart of a motor control method 500 according to an embodiment of the invention. The motor control method of the present embodiment is suitable for a start-up procedure of a sensorless dc brushless motor. In step S502, a phase voltage signal and a driving voltage signal are generated according to the starting current signal and the phase current signal having the first preset value. In step S504, a driving current signal is generated according to the driving voltage signal to drive the dc brushless motor to operate, wherein the first preset value is used to at least maintain the dc brushless motor to operate normally. In step S506, the driving current signal is sensed to generate a corresponding phase current signal.

In step S508, a shaft end load state of the dc brushless motor is determined according to the phase voltage signal (e.g., at least one of the d-axis voltage signal and the q-axis voltage signal) and the starting current signal, which vary with the corresponding phase current signal. In step S510, the magnitude of the start current signal is adaptively adjusted according to the shaft end load state and/or according to the electrical rotation angular velocity and the torque requirement of the dc brushless motor. In other words, the starting current can be directly adjusted only according to the confirmed shaft end load state, or the starting current can be directly adjusted only according to the electric rotation angular velocity and the torque requirement of the dc brushless motor, or the starting current can be adjusted according to the shaft end load state and the electric rotation angular velocity and the torque requirement of the dc brushless motor at different stages. In the present embodiment, the torque requirements include load torque, motor inertia and friction.

Fig. 6 is a flow chart of a motor control method 600 according to another embodiment of the invention. The motor control method 600 of the present embodiment is similar to the motor control method 500. In the present embodiment, the motor control method 600 includes steps S608 to S610 in addition to steps S502 to S506 and S510 in the motor control method 500. In step S608, at least one of the d-axis voltage signal and the q-axis voltage signal, which varies according to the phase current signal, is processed, such as low-pass filtering and integral amplification. Next, the shaft end load status of the dc brushless motor is determined according to the processed d-axis voltage signal and/or q-axis voltage signal and the starting current signal (in step S610).

Fig. 7 is a flowchart of a motor control method 700 according to another embodiment of the invention. The motor control method 700 of the present embodiment is similar to the motor control method 500. In the present embodiment, the motor control method 700 includes steps S710 to S712 in addition to steps S502 to S508 in the motor control method 500. In step S710, the start current signal is adjusted from a first preset value to a second preset value according to the shaft end load state. In some embodiments, step S712 may be selectively performed. In step S712, when the electrical rotation angular velocity of the dc brushless motor reaches the predetermined angular velocity and is maintained at the predetermined angular velocity, the start current signal is adjusted from the second predetermined value to a third predetermined value according to the torque requirement of the dc brushless motor.

Fig. 8 is a flow chart of a motor control method 800 according to another embodiment of the invention. The motor control method 800 of the present embodiment is similar to the motor control method 700, except that steps S810 to S812 are different from steps S710 to S712. In step S810, when the shaft end load status of the dc brushless motor is determined and the electrical rotational angular velocity of the dc brushless motor reaches the predetermined angular velocity and is maintained at the predetermined frequency, the start current signal is adjusted from the first predetermined value to the second predetermined value according to the torque requirement of the dc brushless motor. In some embodiments, step S812 may be selectively performed. In step S812, the start current signal is adjusted from the second preset value to a third preset value according to the shaft end load state.

Fig. 9 is a flow chart of a motor control method 900 according to another embodiment of the invention. The motor control method 900 of the present embodiment is similar to the motor control method 500. In the present embodiment, the motor control method 900 includes step S910 in addition to steps S502 to S508 in the motor control method 500. In step S910, when the end-of-shaft load state is a locked-rotor state, the start current signal is increased from the first preset value to a second preset value by a rising slope, wherein a maximum value of the second preset value is a maximum current allowed by the dc brushless motor. In some embodiments, the magnitude of the slope may be adjusted according to actual requirements to adjust the increasing amplitude of the starting current signal.

In summary, the motor control method and apparatus disclosed in the present invention generate phase voltage signals (e.g., d-axis voltage signals and q-axis voltage signals) and driving voltage signals according to the starting current signals and the phase current signals having the first preset values, and generate driving current signals according to the driving voltage signals to drive the dc brushless motor to operate, and determine the shaft end load state of the dc brushless motor according to at least one of the d-axis voltage signals and the q-axis voltage signals, which are changed along with the phase current signals, and the starting current signals, and adaptively adjust the magnitude of the starting current signals according to the shaft end load state and/or according to the electrical rotation angular velocity and the torque requirement of the dc brushless motor. Therefore, the situation that the electric quantity loss is increased due to the fact that the direct current brushless motor is driven to operate by a larger starting current can be avoided, and the electric quantity loss of the direct current brushless motor in the starting procedure period can be effectively reduced.

Although the present invention has been described with reference to particular embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.