阅读说明：本技术 高速无刷直流电机的换相系统及换相方法 (Phase commutation system and method of high-speed brushless direct current motor ) 是由 刘刚 金浩 郑世强 陈宝栋 张海峰 于 2020-12-22 设计创作，主要内容包括：本发明实施例公开了一种高速无刷直流电机的换相系统及换相方法。换相系统包括使能信号发生电路、窗口发生电路、反馈量获取电路和控制电路；反馈量获取电路的输入端分别与电机的三相绕组和中性点电连接,反馈量获取电路的使能端与使能信号发生电路的输出端电连接,反馈量获取电路的控制端与窗口发生电路的输出端电连接；反馈量获取电路用于根据使能信号、窗口信号、三相端电压和中性点电压形成重构悬空相反电动势,并获取反馈量；控制电路的反馈输入端与反馈量获取电路的输出端电连接,控制电路的信号输入端与虚拟霍尔信号电连接,控制电路的输出端与窗口发生电路的输入端电连接；控制电路,用于根据反馈量和虚拟霍尔信号产生换相信号。(The embodiment of the invention discloses a phase commutation system and a phase commutation method of a high-speed brushless direct current motor. The commutation system comprises an enabling signal generating circuit, a window generating circuit, a feedback quantity acquiring circuit and a control circuit; the input end of the feedback quantity acquisition circuit is electrically connected with a three-phase winding and a neutral point of the motor respectively, the enabling end of the feedback quantity acquisition circuit is electrically connected with the output end of the enabling signal generation circuit, and the control end of the feedback quantity acquisition circuit is electrically connected with the output end of the window generation circuit; the feedback quantity acquisition circuit is used for forming a reconstructed suspended counter electromotive force according to the enable signal, the window signal, the three-phase end voltage and the neutral point voltage and acquiring feedback quantity; the feedback input end of the control circuit is electrically connected with the output end of the feedback quantity acquisition circuit, the signal input end of the control circuit is electrically connected with the virtual Hall signal, and the output end of the control circuit is electrically connected with the input end of the window generation circuit; and the control circuit is used for generating a phase change signal according to the feedback quantity and the virtual Hall signal.)

1. A commutation system of a high-speed brushless direct current motor is characterized by comprising an enabling signal generating circuit, a window generating circuit, a feedback quantity acquiring circuit and a control circuit;

the input end of the feedback quantity acquisition circuit is respectively and electrically connected with a three-phase winding and a neutral point of the motor, the enabling end of the feedback quantity acquisition circuit is electrically connected with the output end of the enabling signal generation circuit, and the control end of the feedback quantity acquisition circuit is electrically connected with the output end of the window generation circuit; the feedback quantity acquisition circuit is used for forming a reconstructed suspended counter electromotive force according to the enable signal, the window signal, the three-phase end voltage and the neutral point voltage, and integrating the reconstructed suspended counter electromotive force in one period to acquire the feedback quantity;

the feedback input end of the control circuit is electrically connected with the output end of the feedback quantity acquisition circuit, and the signal input end of the control circuit is electrically connected with the collected virtual Hall signal; and the control circuit is used for generating a phase change signal according to the feedback quantity and the virtual Hall signal.

2. The commutation system of claim 1, wherein the feedback amount acquisition circuit comprises a back electromotive force acquisition circuit, an inverter circuit, a multiplexing circuit, and a low-pass filter circuit;

the three-phase voltage input end of the counter electromotive force acquisition circuit is electrically connected with the three-phase windings in a one-to-one correspondence manner, and the neutral point voltage input end of the counter electromotive force acquisition circuit is electrically connected with the neutral point; the back electromotive force acquisition circuit is used for acquiring a three-phase back electromotive force according to the three-phase terminal voltage and the neutral point voltage;

the back electromotive force input end of the phase inverting circuit is electrically connected with the back electromotive force output end of the back electromotive force acquisition circuit in a one-to-one correspondence manner; the phase inversion circuit is used for acquiring three-phase reverse electromotive force according to the three-phase reverse electromotive force;

a plurality of input ends of the multiplexing circuit are respectively and correspondingly electrically connected with the back electromotive force output end and the inverted back electromotive force output end of the inverter circuit, an enabling end of the multiplexing circuit is electrically connected with the output end of the enabling signal generating circuit, and a control end of the multiplexing circuit is electrically connected with the output end of the window generating circuit; the multiplexing circuit is used for generating the reconstructed suspended counter electromotive force according to the enabling signal, the window signal, the three-phase counter electromotive force and the three-phase reverse-phase counter electromotive force;

the input end of the low-pass filter is electrically connected with the output end of the multiplexing circuit, and the low-pass filter is used for integrating the reconstructed suspended counter electromotive force in one period to obtain the feedback quantity.

3. The commutation system of claim 1 or 2, wherein the control circuit comprises a comparator, a controller and a phase shifter;

a first input end of the comparator is electrically connected with an output end of the feedback quantity acquisition circuit, and a second input end of the comparator is grounded; the comparator is used for converting the feedback analog quantity into a feedback digital quantity;

the input end of the controller is electrically connected with the output end of the comparator, and the controller is used for determining a compensation phase according to the feedback digital quantity;

a first input end of the phase shifter is electrically connected with the virtual Hall signal, and a second input end of the phase shifter is electrically connected with an output end of the controller; the phase shifter is used for compensating the virtual Hall signal according to the compensation phase to generate the phase change signal.

4. The commutation system of claim 1 or 2, further comprising a freewheeling pulse angle capture circuit;

the control end of the follow current pulse angle capturing circuit is electrically connected with the output end of the control circuit through a phase change logic control circuit, and the input end of the follow current pulse angle capturing circuit is electrically connected with the pulse generator; the commutation logic control circuit is used for generating a control signal according to the commutation signal; and the follow current pulse angle capturing circuit is used for generating a corresponding driving signal according to the control signal so as to drive the motor, and is also used for acquiring a pulse corresponding to follow current time.

5. The commutation system of claim 4, wherein the enable signal generation circuit comprises an OR gate, a phase shifter, and a logic processor;

the input end of the OR gate is electrically connected with the output end of the follow current pulse angle capturing circuit, and the OR gate generates a pulse signal according to the pulse corresponding to the follow current time;

the input end of the phase shifter is electrically connected with the output end of the OR gate and is used for delaying the pulse signal by 60 degrees to form a delayed pulse signal;

and two input ends of the logic processor are respectively electrically connected with the output end of the OR gate and the output end of the phase shifter, and the logic processor is used for setting the rising edge of the delay pulse signal to 1 and setting the falling edge of the pulse signal to 0 so as to form the enable signal.

6. A commutation method of a high-speed brushless DC motor is characterized in that the commutation method is suitable for a commutation system of the high-speed brushless DC motor, and the commutation system comprises an enabling signal generating circuit, a window generating circuit, a feedback quantity obtaining circuit and a control circuit;

the input end of the feedback quantity acquisition circuit is respectively and electrically connected with a three-phase winding and a neutral point of the motor, the enabling end of the feedback quantity acquisition circuit is electrically connected with the output end of the enabling signal generation circuit, and the control end of the feedback quantity acquisition circuit is electrically connected with the output end of the window generation circuit; the feedback input end of the control circuit is electrically connected with the output end of the feedback quantity acquisition circuit, and the signal input end of the control circuit is electrically connected with the collected virtual Hall signal;

the phase commutation method comprises the following steps:

forming a reconstructed suspended counter electromotive force according to the enabling signal, the window signal, the three-phase terminal voltage and the neutral point voltage;

integrating the reconstructed suspended counter electromotive force in a period to obtain a feedback quantity;

and generating a commutation signal according to the feedback quantity and the collected virtual Hall signal.

7. The commutation method of claim 6, wherein the forming a reconstructed hanging back emf from the enable signal, the window signal, and the three phase voltages comprises:

acquiring three-phase back electromotive force according to the three-phase terminal voltage and the neutral point voltage;

acquiring three-phase reverse-phase counter electromotive force according to the three counter electromotive force;

and generating the reconstructed suspended counter electromotive force according to the enable signal, the window signal, the three-phase counter electromotive force and the three-phase reverse counter electromotive force.

8. The commutation method of claim 7, wherein the integrating the reconstructed floating back emf over a period to obtain a feedback quantity comprises:

calculating the feedback quantity u 'according to the following formula'_r：

Wherein u is_rFor the reconstruction of the suspended counter electromotive force, T is the period of the reconstructed suspended counter electromotive force, and T is time.

9. The commutation method of any one of claims 6-8, wherein generating a commutation signal based on the feedback quantity and the collected virtual hall signal comprises:

converting the feedback analog quantity into a feedback digital quantity;

determining a compensation phase according to the feedback digital quantity;

and compensating the virtual Hall signal according to the compensation phase to generate the commutation signal.

10. The commutation method of any one of claims 6 to 8, wherein before the forming the reconstructed floating back emf from the enable signal, the window signal, and the three-phase terminal and neutral voltages, further comprising:

acquiring a pulse corresponding to the follow current time and generating a pulse signal;

delaying the pulse signal by 60 ° to form a delayed pulse signal;

setting a rising edge of the delayed pulse signal to 1 and a falling edge of the pulse signal to 0 to form the enable signal.

Technical Field

The invention belongs to the technical field of motors, and particularly relates to a phase commutation system and a phase commutation method of a high-speed brushless direct current motor.

Background

The brushless direct current motor commutation method can adopt three paths of Hall signals or encoders to form six paths of commutation signals through level high-low combination, but the installation of the position sensor not only increases the power consumption of the system, but also reduces the reliability of the system, so the commutation method without the position sensor becomes a research hotspot in recent years. The back electromotive force zero crossing point method is widely applied to industry as a phase change method without a position sensor due to simplicity and reliability, but the phase change precision is influenced and the working performance of a motor is reduced due to the fact that a processing circuit causes the lag of a detection signal, so that the phase change method of an area integration method is provided.

In the prior art, the phase change of the area integration method generally needs to carry out high-frequency sampling on signals, a sampling circuit is realized on the basis of software, and because the electric cycle of a motor is very small when the motor runs at a high speed, the sampling density of the integrated signals is low, the sampling precision is reduced, the area is calculated incorrectly, and the phase change error is caused.

Disclosure of Invention

In order to solve the technical problem or at least partially solve the technical problem, the present disclosure provides a commutation system and a commutation method for a high-speed brushless dc motor, which can reduce commutation errors.

In a first aspect, an embodiment of the present invention provides a phase commutation system for a high-speed brushless dc motor, including an enable signal generating circuit, a window generating circuit, a feedback quantity obtaining circuit, and a control circuit;

the input end of the feedback quantity acquisition circuit is respectively and electrically connected with a three-phase winding and a neutral point of the motor, the enabling end of the feedback quantity acquisition circuit is electrically connected with the output end of the enabling signal generation circuit, and the control end of the feedback quantity acquisition circuit is electrically connected with the output end of the window generation circuit; the feedback quantity acquisition circuit is used for forming a reconstructed suspended counter electromotive force according to the enable signal, the window signal, the three-phase end voltage and the neutral point voltage, and integrating the reconstructed suspended counter electromotive force in one period to acquire the feedback quantity;

the feedback input end of the control circuit is electrically connected with the output end of the feedback quantity acquisition circuit, and the signal input end of the control circuit is electrically connected with the collected virtual Hall signal; and the control circuit is used for generating a phase change signal according to the feedback quantity and the virtual Hall signal.

Optionally, the feedback quantity acquiring circuit includes a back electromotive force acquiring circuit, an inverting circuit, a multiplexing circuit, and a low-pass filter circuit;

the three-phase voltage input end of the counter electromotive force acquisition circuit is electrically connected with the three-phase windings in a one-to-one correspondence manner, and the neutral point voltage input end of the counter electromotive force acquisition circuit is electrically connected with the neutral point; the back electromotive force acquisition circuit is used for acquiring a three-phase back electromotive force according to the three-phase terminal voltage and the neutral point voltage;

the back electromotive force input end of the phase inverting circuit is electrically connected with the back electromotive force output end of the back electromotive force acquisition circuit in a one-to-one correspondence manner; the phase inversion circuit is used for acquiring three-phase reverse electromotive force according to the three-phase reverse electromotive force;

a plurality of input ends of the multiplexing circuit are respectively and correspondingly electrically connected with the back electromotive force output end and the inverted back electromotive force output end of the inverter circuit, an enabling end of the multiplexing circuit is electrically connected with the output end of the enabling signal generating circuit, and a control end of the multiplexing circuit is electrically connected with the output end of the window generating circuit; the multiplexing circuit is used for generating the reconstructed suspended counter electromotive force according to the enabling signal, the window signal, the three-phase counter electromotive force and the three-phase reverse-phase counter electromotive force;

the input end of the low-pass filter is electrically connected with the output end of the multiplexing circuit, and the low-pass filter is used for integrating the reconstructed suspended counter electromotive force in one period to obtain the feedback quantity.

Optionally, the control circuit comprises a comparator, a controller and a phase shifter;

a first input end of the comparator is electrically connected with an output end of the feedback quantity acquisition circuit, and a second input end of the comparator is grounded; the comparator is used for converting the feedback analog quantity into a feedback digital quantity;

the input end of the controller is electrically connected with the output end of the comparator, and the controller is used for determining a compensation phase according to the feedback digital quantity;

a first input end of the phase shifter is electrically connected with the virtual Hall signal, and a second input end of the phase shifter is electrically connected with an output end of the controller; the phase shifter is used for compensating the virtual Hall signal according to the compensation phase to generate the phase change signal.

Optionally, a freewheeling pulse angle capture circuit is also included;

the control end of the follow current pulse angle capturing circuit is electrically connected with the output end of the control circuit through a phase change logic control circuit, and the input end of the follow current pulse angle capturing circuit is electrically connected with the pulse generator; the commutation logic control circuit is used for generating a control signal according to the commutation signal; and the follow current pulse angle capturing circuit is used for generating a corresponding driving signal according to the control signal so as to drive the motor, and is also used for acquiring a pulse corresponding to follow current time.

Optionally, the enable signal generating circuit comprises an or gate, a phase shifter and a logic processor;

the input end of the OR gate is electrically connected with the output end of the follow current pulse angle capturing circuit, and the OR gate generates a pulse signal according to the pulse corresponding to the follow current time;

the input end of the phase shifter is electrically connected with the output end of the OR gate and is used for delaying the pulse signal by 60 degrees to form a delayed pulse signal;

and two input ends of the logic processor are respectively electrically connected with the output end of the OR gate and the output end of the phase shifter, and the logic processor is used for setting the rising edge of the delay pulse signal to 1 and setting the falling edge of the pulse signal to 0 so as to form the enable signal.

In a second aspect, an embodiment of the present invention provides a phase commutation method for a high-speed brushless dc motor, which is applicable to a phase commutation system of a high-speed brushless dc motor, where the phase commutation system includes an enable signal generating circuit, a window generating circuit, a feedback quantity obtaining circuit, and a control circuit;

the input end of the feedback quantity acquisition circuit is respectively and electrically connected with a three-phase winding and a neutral point of the motor, the enabling end of the feedback quantity acquisition circuit is electrically connected with the output end of the enabling signal generation circuit, and the control end of the feedback quantity acquisition circuit is electrically connected with the output end of the window generation circuit; the feedback input end of the control circuit is electrically connected with the output end of the feedback quantity acquisition circuit, and the signal input end of the control circuit is electrically connected with the collected virtual Hall signal;

the phase commutation method comprises the following steps:

forming a reconstructed suspended counter electromotive force according to the enabling signal, the window signal, the three-phase terminal voltage and the neutral point voltage;

integrating the reconstructed suspended counter electromotive force in a period to obtain a feedback quantity;

and generating a commutation signal according to the feedback quantity and the collected virtual Hall signal.

Optionally, the forming of the reconstructed suspended counter electromotive force according to the enable signal, the window signal and the three-phase voltage includes:

acquiring three-phase back electromotive force according to the three-phase terminal voltage and the neutral point voltage;

acquiring three-phase reverse-phase counter electromotive force according to the three counter electromotive force;

and generating the reconstructed suspended counter electromotive force according to the enable signal, the window signal, the three-phase counter electromotive force and the three-phase reverse counter electromotive force.

Optionally, the integrating the reconstructed floating back electromotive force in one period to obtain a feedback quantity includes:

calculating the feedback quantity u 'according to the following formula'_r：

Wherein u is_rFor the reconstruction of the suspended counter electromotive force, T is the period of the reconstructed suspended counter electromotive force, and T is time.

Optionally, the generating a commutation signal according to the feedback quantity and the collected virtual hall signal includes:

converting the feedback analog quantity into a feedback digital quantity;

determining a compensation phase according to the feedback digital quantity;

and compensating the virtual Hall signal according to the compensation phase to generate the commutation signal.

Optionally, before the forming of the reconstructed floating back electromotive force according to the enable signal, the window signal, the three-phase terminal voltage and the neutral-point voltage, the method further includes:

acquiring a pulse corresponding to the follow current time and generating a pulse signal;

delaying the pulse signal by 60 ° to form a delayed pulse signal;

setting a rising edge of the delayed pulse signal to 1 and a falling edge of the pulse signal to 0 to form the enable signal.

Compared with the prior art, the technical scheme provided by the embodiment of the invention has the following advantages:

in the technical scheme provided by the embodiment of the invention, the input end of the feedback quantity acquisition circuit is respectively and electrically connected with the three-phase winding and the neutral point of the motor, the enable end of the feedback quantity acquisition circuit is electrically connected with the output end of the enable signal generation circuit, the control end of the feedback quantity acquisition circuit is electrically connected with the output end of the window generation circuit, the feedback quantity acquisition circuit can acquire the enable signal output by the output end of the enable signal generation circuit, the window signal output by the window generation circuit, the terminal voltage of the three-phase winding and the voltage of the neutral point, reconstructed suspended counter electromotive force is formed according to the enable signal, the window signal, the terminal voltage of the three-phase winding and the voltage of the neutral point, and the feedback quantity can be acquired by integrating the reconstructed suspended counter electromotive force in one. The feedback input end of the control circuit is electrically connected with the output end of the feedback quantity acquisition circuit, the signal input end of the control circuit is electrically connected with the collected virtual Hall signal, and the control circuit can adjust the virtual Hall signal according to the feedback quantity to generate a phase change signal. Therefore, the technical scheme provided by the embodiment of the invention can acquire the feedback quantity through the hardware circuit, improve the acquisition speed of the feedback quantity, and improve the sampling frequency, thereby improving the precision of the integral quantity, reducing the commutation error and realizing the high-precision commutation of the motor. In addition, the hardware circuit can save interrupt resources, analog-to-digital conversion resources and calculation resources of the commutation system.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the invention and together with the description, serve to explain the principles of the invention.

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without inventive exercise.

Fig. 1 is a schematic structural diagram of a phase commutation system of a high-speed brushless dc motor according to an embodiment of the present invention;

fig. 2 is a waveform diagram of reconstructed floating back emf when commutation is accurate according to an embodiment of the present invention;

FIG. 3 is a waveform diagram of a reconstructed floating bemf during phase-commutation lag according to an embodiment of the present invention;

FIG. 4 is a waveform diagram of a reconstructed floating EMF during phase-change advancing according to an embodiment of the present invention;

fig. 5 is a schematic waveform diagram of signals related to a high-speed brushless dc motor according to an embodiment of the present invention;

fig. 6 is a schematic diagram of waveforms of floating bemf according to an embodiment of the present invention;

fig. 7 is a schematic flowchart of a phase-changing method of a high-speed brushless dc motor according to an embodiment of the present invention;

fig. 8 is a schematic flowchart of a phase-changing method for a high-speed brushless dc motor according to another embodiment of the present invention;

fig. 9 is a schematic flowchart of a phase-changing method for a high-speed brushless dc motor according to another embodiment of the present invention;

fig. 10 is a schematic flowchart of a phase-changing method of a high-speed brushless dc motor according to another embodiment of the present invention.

Detailed Description

In order that the above objects, features and advantages of the present invention may be more clearly understood, a solution of the present invention will be further described below. It should be noted that the embodiments of the present invention and features of the embodiments may be combined with each other without conflict.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention, but the present invention may be practiced in other ways than those described herein; it is to be understood that the embodiments described in this specification are only some embodiments of the invention, and not all embodiments.

Fig. 1 is a schematic structural diagram of a phase commutation system of a high-speed brushless dc motor according to an embodiment of the present invention, and as shown in fig. 1, the phase commutation system 100 of the high-speed brushless dc motor includes an enable signal generating circuit 110, a window generating circuit 120, a feedback quantity obtaining circuit 130, and a control circuit 140.

Wherein, the input end of the feedback quantity obtaining circuit 130 is electrically connected to the three-phase winding and the neutral point N of the motor 150, the enable end of the feedback quantity obtaining circuit 130 is electrically connected to the output end of the enable signal generating circuit 110, and the control end of the feedback quantity obtaining circuit 130 is electrically connected to the output end of the window generating circuit 120. And the feedback quantity acquisition circuit is used for forming reconstructed suspended counter electromotive force according to the enable signal, the window signal, the three-phase end voltage and the neutral point voltage, and integrating the reconstructed suspended counter electromotive force in one period to acquire the feedback quantity.

A feedback input end of the control circuit 140 is electrically connected with an output end of the feedback quantity acquisition circuit 130, and a signal input end of the control circuit 140 is electrically connected with the collected virtual hall signal; and the control circuit 140 is used for adjusting the virtual Hall signal according to the feedback quantity to generate a phase change signal.

Illustratively, as shown in fig. 1, the motor 150 includes an a-phase winding, a B-phase winding, and a C-phase winding, and four input terminals of the feedback amount acquisition circuit 130 are electrically connected to the a-phase winding, the B-phase winding, the C-phase winding, and the neutral point N, respectively, i.e., the feedback amount acquisition circuit 130 is capable of receiving an a-phase terminal voltage, a B-phase terminal voltage, a C-phase terminal voltage, and a neutral point voltage. The enable terminal of the feedback quantity obtaining circuit 130 is electrically connected to the output terminal of the enable signal generating circuit 110, the feedback quantity obtaining circuit 130 can receive the enable signal output by the enable signal generating circuit 110, and the feedback quantity obtaining circuit 130 operates under the effect of the enable signal. For example, the enable signal may be a low level signal, and the feedback amount acquisition circuit 130 operates by the low level signal. In other embodiments, the enable signal may also be a high level signal.

The control terminal of the feedback quantity obtaining circuit 130 is electrically connected to the output terminal of the window generating circuit 120, the feedback quantity obtaining circuit 130 can receive the window signal output by the window generating circuit 120, and the window signal can select a specific window for the input signal and output a signal of the window area. Therefore, the feedback quantity obtaining circuit 130 can determine the reconstructed floating counter electromotive force according to the a-phase terminal voltage, the B-phase terminal voltage, the C-phase terminal voltage, the neutral point voltage and the window signal under the effect of the enable signal. The feedback amount acquisition circuit 130 integrates the reconstructed floating counter electromotive force in one period thereof according to the reconstructed floating counter electromotive force, thereby acquiring a feedback amount.

Fig. 2 is a waveform diagram of reconstructed floating bemf during accurate commutation according to an embodiment of the present invention, fig. 3 is a waveform diagram of reconstructed floating bemf during lagging commutation according to an embodiment of the present invention, and fig. 4 is a waveform diagram of reconstructed floating bemf during leading commutation according to an embodiment of the present invention. With reference to fig. 2-4, the suspended opposite electromotive force is reconstructedThe integration of the potential over one period results in the area S after the zero point time within the period₂Area S before zero point time₁Area difference value DeltaS, feedback quantity u'_rIs positively correlated with the area difference value Delta S, so that the feedback quantity u 'can be obtained'_r。

A feedback input terminal of the control circuit 140 is electrically connected to an output terminal of the feedback quantity acquiring circuit 130, and the control circuit 140 can receive the feedback quantity u'_r. Three input ends of the zero detection circuit 160 are correspondingly and electrically connected with the phase A winding, the phase B winding and the phase C winding, three output ends of the zero detection circuit 160 are correspondingly and electrically connected with three signal input ends of the control circuit 140, and the zero detection circuit 160 can generate a phase A virtual Hall signal Ha, a phase B virtual Hall signal Hb and a phase C virtual Hall line number Hc according to the phase A end voltage, the phase B end voltage and the phase C end voltage respectively. Three signal input ends of the control circuit 140 are correspondingly and electrically connected with three output ends of the zero point detection circuit 160, and the control circuit 140 can receive the a-phase virtual hall signal Ha, the B-phase virtual hall signal Hb, and the C-phase virtual hall line number Hc.

Illustratively, as in fig. 2-4, when commutation is accurate, Δ S ═ 0, feedback quantity u'_r0; at delayed commutation, Δ S>0, feedback quantity u'_r>0; when phase change is advanced, Δ S<0, feedback quantity u'_r<0. When commutation phase is advanced or retarded, the feedback quantity u'_rIs inputted to the control circuit 140, and the control circuit 140 can be operated in accordance with the feedback amount u'_rDetermining whether the phase change is accurate, lagged or advanced, and adjusting the A-phase virtual Hall signal Ha, the B-phase virtual Hall signal Hb and the C-phase virtual Hall line number Hc according to the determination to generate the A-phase commutation signal Sa, the B-phase commutation signal Sb and the C-phase commutation signal Sc so as to enable the feedback quantity u'_rTending to 0 and thereby reducing commutation errors.

In summary, according to the technical scheme provided by the embodiment of the present invention, the construction of the reconstructed suspended counter electromotive force and the process of generating the feedback quantity by integration are both implemented by a hardware circuit, and since the operation speed of the hardware circuit is fast, the acquisition speed of the feedback quantity is fast, so that the sampling frequency of the commutation system 100 can be increased, the accuracy of the integration quantity can be increased, the commutation error can be reduced, and the high-accuracy commutation of the motor can be realized. In addition, since the hardware circuit performs operations such as sampling and integration, the interrupt resources, analog-to-digital conversion resources, and calculation resources of the commutation system 100 of the high-speed brushless dc motor can be saved.

Alternatively, with continued reference to fig. 1, the feedback amount acquisition circuit 130 includes a counter electromotive force acquisition circuit 131, an inverter circuit 132, a multiplexing circuit 133, and a low-pass filter circuit 134.

The three-phase voltage input end of the counter electromotive force acquisition circuit 131 is electrically connected with the three-phase winding in a one-to-one correspondence manner, and the neutral point voltage input end of the counter electromotive force acquisition circuit 131 is electrically connected with the neutral point N; and a back electromotive force acquisition circuit 131 for acquiring a three-phase back electromotive force from the three-phase terminal voltage and the neutral point voltage.

The counter electromotive force input terminal of the inverter circuit 132 is electrically connected to the counter electromotive force output terminal of the counter electromotive force acquisition circuit 131 in a one-to-one correspondence. And an inverter circuit 132 for obtaining three-phase reverse electromotive force from the three-phase reverse electromotive force.

A plurality of input terminals of the multiplexing circuit 133 are electrically connected to the back electromotive force output terminal and the inverted back electromotive force output terminal of the inverter circuit 132 in a one-to-one correspondence, respectively, an enable terminal of the multiplexing circuit 133 is electrically connected to the output terminal of the enable signal generating circuit 110, and a control terminal of the multiplexing circuit 133 is electrically connected to the output terminal of the window generating circuit 120. And a multiplexing circuit 133 for generating a reconstructed floating back electromotive force according to the enable signal, the window signal, the three-phase back electromotive force, and the three-phase reverse back electromotive force.

The input end of the low-pass filter 134 is electrically connected to the output end of the multiplexing circuit 133, and the low-pass filter 134 is configured to integrate the reconstructed floating back electromotive force in one cycle to obtain a feedback amount.

Illustratively, as shown in fig. 1, the back electromotive force acquiring circuit 131 includes three subtractors, first input terminals of which are electrically connected to the a-phase winding, the B-phase winding, and the C-phase winding, respectively, and second input terminals of which are electrically connected to a neutral point. That is, the first input terminals of the three subtractors are all three-phase voltage input terminals of the back electromotive force acquisition circuit 131, and the second input terminals of the three subtractors are all neutral point voltage input terminals of the back electromotive force acquisition circuit 131.

Three subtractors are respectively based on A phase terminal voltage u_aTo neutral point voltage u_aCalculating phase voltage u of phase A_anAccording to the voltage u of the phase-B terminal_bTo neutral point voltage u_nCalculating the phase voltage u of phase B_bnAccording to the voltage u of the phase C terminal_cTo neutral point voltage u_nCalculating the phase voltage u of C phase_cnTherefore, the counter electromotive force acquisition circuit 131 can obtain the voltage u from the a-phase terminal_aVoltage u at phase B terminal_bC phase terminal voltage u_cAnd neutral point voltage u_nCalculating phase voltage u of phase A_anPhase voltage u of phase B_bnAnd phase voltage u of C_cn。

The balance equation of a brushless dc motor is as follows:

wherein L is the phase inductance of the brushless DC motor, R is the phase resistance of the brushless DC motor, e_aIs A counter electromotive force, e_bIs B counter electromotive force, e_cIs C counter electromotive force, N is neutral point of stator winding in brushless DC motor, i_aFor phase A current, i_bIs phase B current, i_cPhase C current, t is time.

When the A phase winding is suspended, the A phase current i_aIs 0, phase voltage u of A phase_anEqual to A counter electromotive force e_aWhen the phase B winding is suspended, the phase B current i_bIs 0, B phase voltage u_bnEqual to B counter electromotive force e_bWhen the C phase winding is suspended, the C phase current i_cIs 0, C phase voltage u_cnEqual to C counter electromotive force e_c. Therefore, the counter electromotive force acquisition circuit 131 can acquire the voltage u from the a-phase terminal_aVoltage u at phase B terminal_bC phase terminal voltage u_cAnd neutral point voltage u_nCalculating the A counter electromotive force e_aB counter electromotive force e_bAnd C counter electromotive force e_c. A counter electromotive force e_aB counter electromotive force e_bAnd C counter electromotive force e_cThe signal of (2) is shown in fig. 5.

Illustratively, as shown in fig. 1, the inverter circuit 132 includes three inverters, and input terminals of the three inverters are electrically connected to corresponding output terminals of the three subtractors, i.e. the input terminals of the three inverters are all back electromotive force input terminals of the inverter circuit 132. Three inverters respectively output A opposite and opposite electromotive forces-e_aReverse phase counter electromotive force-e of B direction_bAnd C-direction reverse-phase counter electromotive force-e_c. A is counter-electromotive force-e_aReverse phase counter electromotive force-e of B direction_bAnd C-direction reverse-phase counter electromotive force-e_cThe signal of (2) is shown in fig. 5.

Six input terminals of the multiplexing circuit 133 are electrically connected to output terminals of the three subtractors and the three inverters, respectively, and the multiplexing circuit 133 can receive the a-phase electromotive force e_aB phase end counter electromotive force e_bC counter electromotive force e_cAnd A-direction reverse-phase counter electromotive force-e_aReverse phase counter electromotive force-e of B direction_bAnd C-direction reverse-phase counter electromotive force-e_c. The multiplexer circuit 133 starts operating by the enable signal, and for example, when the enable signal is a low level signal, the multiplexer circuit 133 starts operating. The multiplexing circuit 133 gates the switches of the multiplexing circuit 133 according to the window signal, and finally forms a reconstructed floating back emf. The reconstruction of the floating counter electromotive force is explained in detail below:

fig. 6 is a waveform schematic diagram of a floating back emf provided by an embodiment of the present invention, where the acquisition frequency is lower when the motor is running at a high speed, and the acquisition time needs to be increased to acquire more acquired signals in order to obtain a more accurate area, and the longer the acquisition time is, the closer to a period is, as shown in fig. 6, the floating back emf follows an edge e in the period_xAnd the delta S is zero when the suspended opposite electromotive force is integrated in one period no matter the phase change is accurate, the phase change is advanced or the phase change is delayed. Therefore, no matter whether the phase change is accurate or not, the feedback quantity u 'acquired based on the suspended counter electromotive force'_rAre all close to zero, resulting in a feedback quantity u'_rThe error is large.

In the embodiment of the present invention, the inverse electromotive force that is in a downward trend in the floating electromotive forces shown in fig. 6 can be inverted with respect to the time axis through the inverting circuit 132 and the multiplexing circuit 133 to form the reconstructed floating electromotive force shown in fig. 2-4, and the reconstructed floating electromotive force breaks the floating electromotive force and breaks the edge e of the floating electromotive force in the period_xDue to the axisymmetric relation, integral miscalculation caused by low sampling frequency is avoided, and the error of the feedback quantity is reduced, so that the commutation error is reduced.

The low-pass filter 134 can filter out the high-frequency component in the reconstructed floating counter electromotive force, output the direct-current component in the reconstructed floating counter electromotive force, and reconstruct the floating counter electromotive force u_rAfter Fourier decomposition, the following results are obtained:

wherein the content of the first and second substances,a₀is the direct current component, ω is the angular velocity, T is the period, and T is the time.

Direct current component a₀Equal to:

therefore, the output signal of the low pass filter 134 is the floating back electromotive force u for the reconstruction in one cycle_rThe product of the result of the integration and the coefficient 2/T, i.e. the product of the area difference Δ S and the coefficient 2/T, is passed through the low pass filter 134 for the DC component a₀Namely the feedback quantity u'_r. In the high-speed brushless DC motor, the period T is far less than 1, so the coefficient 2/T has amplification effect on the area difference value delta S and the feedback quantity u'_rThe phase change error can be more effectively controlled by amplifying the actual phase change error and more prominently displaying the phase change error when the phase change error is smaller. In addition, along with the increase of the rotating speed of the motor, the commutation error control is more accurate.

Optionally, with continued reference to fig. 1, control circuit 140 includes a comparator 141, a controller 142, and a phase shifter 143.

A first input terminal of the comparator 141 is electrically connected to the output terminal of the feedback quantity obtaining circuit 130, and a second input terminal of the comparator 141 is grounded. And a comparator 141 for converting the feedback analog quantity into a feedback digital quantity. An input terminal of the controller 142 is electrically connected to an output terminal of the comparator 141, and the controller 142 is configured to determine the compensation phase according to the feedback digital quantity. A first input terminal of the phase shifter 143 is electrically connected to the virtual hall signal, a second input terminal of the phase shifter 143 is electrically connected to an output terminal of the controller 142, and the phase shifter 143 is configured to compensate the virtual hall signal according to the compensated phase to generate a phase-shifted signal.

Specifically, the feedback amount u 'output from the feedback amount acquisition circuit 130'_rIs an analog quantity, and the comparator 141 receives a feedback quantity u'_rThen, it is compared with 0 if u'_r>0, comparator 141 outputs 1; if u'_r<0, the comparator 141 outputs 0. The output signal of the comparator 141 can only be 0 or 1, and thus the feedback analog quantity can be converted into a feedback digital quantity for the controller 142 to recognize and perform correlation processing. Therefore, the analog-to-digital converter can be avoided, and hardware resources and software resources are saved.

The controller 142 is capable of performing the functions of:

wherein the content of the first and second substances,for phase compensation, k is the gain factor, a is the attenuation factor, t is time, sgn is the step function, u "_rFor commands generated internally by the controller 142, if the controller 142 receives a feedback digital quantity of 1, u "_r1 ═ 1; if the controller 142 receives a feedback digital value of 0, u "_r＝-1。

If the commutation is delayed, the feedback quantity u'_r>0, feedbackNumerical quantity 1, u "_rCompensating for phase +1If the commutation phase is advanced, the feedback quantity u'_r<0, feedback digital quantity is 0, u "_rCompensating for phase 1Thus, respective compensation phases are generated according to the phase change lead or lag.

Illustratively, when the commutation is delayed,so that the phases of the A-phase commutation signal Sa, the B-phase commutation signal Sb and the C-phase commutation signal Sc are shifted forward compared with the phases of the A-phase virtual Hall signal Ha, the B-phase virtual Hall signal Hb and the C-phase virtual Hall signal Hc, thereby making the feedback amount u'_rTending to 0. When the phase-change is advanced, the phase-change is carried out,so that the phases of the a-phase commutation signal Sa, the B-phase commutation signal Sb, and the C-phase commutation signal Sc are shifted backward as compared with the phases of the a-phase virtual hall signal Ha, the B-phase virtual hall signal Hb, and the C-phase virtual hall line signal Hc, thereby making Δ S tend to 0. Therefore, the phase shifter 143 can compensate the phase according to the compensated phaseAdjusting the A-phase virtual Hall signal Ha, the B-phase virtual Hall signal Hb and the C-phase virtual Hall signal Hc to make the feedback quantity u'_rTending to 0.

Optionally, with continued reference to fig. 1, the commutation system 100 for a high speed brushless dc motor further includes a freewheel pulse angle capture circuit 170.

The control end of the freewheeling pulse angle capturing circuit 170 is electrically connected to the output end of the control circuit 140 through the phase-change logic control circuit 180, and the input end of the freewheeling pulse angle capturing circuit 170 is electrically connected to the pulse generator 190. The commutation logic control circuit 180 is configured to generate a control signal according to the commutation signal, and the follow current pulse angle capturing circuit 170 is configured to generate a corresponding driving signal according to the control signal to drive the motor 150, and is further configured to obtain a pulse corresponding to the follow current time.

Illustratively, as shown in fig. 1, the freewheel pulse angle capture circuit 170 includes six transistors T1-T6, and six output terminals of the commutation logic control circuit 180 are electrically connected to control terminals of the six transistors, respectively. The commutation logic control circuit 180 can generate control signals to control the on/off of the six transistors in the freewheel pulse angle capturing circuit 170 according to the a-phase commutation signal Sa, the B-phase commutation signal Sb, and the C-phase commutation signal Sc. The follow current Pulse angle capturing circuit 170 opens some transistors and closes some transistors according to the control signal, and a Pulse Width Modulation (PWM) signal output by the Pulse generator 190 passes through the closed transistors to generate a driving signal to drive the motor 150 to rotate.

In the phase-changing process, a voltage peak value can occur in the phase-changing follow current time, in the high-speed brushless direct current motor, the proportion of the follow current time width in a period is large, the follow current time width cannot be ignored, and pulses in the follow current time are not beneficial to accurate calculation of integral of reconstructed suspended counter electromotive force in the period. The freewheel pulse angle capture circuit 170 further includes a freewheel pulse acquisition circuit capable of acquiring a corresponding pulse within the commutation freewheel time so as to subsequently avoid the influence of the pulse within the freewheel time on the integration.

Optionally, with continued reference to fig. 1, the enable signal generation circuit 110 includes an or gate 111, a phase shifter 112, and a logic processor 113.

Wherein, the input end of the or gate 111 is electrically connected with the output end of the follow current pulse angle capturing circuit 170, and the or gate 111 generates the pulse signal P according to the pulse corresponding to the follow current time. An input terminal of the phase shifter 112 is electrically connected to an output terminal of the or gate 111 for delaying the pulse signal P by 60 ° to form a delayed pulse signal P'. Two input terminals of the logic processor 113 are electrically connected to the output terminal of the or gate 111 and the output terminal of the phase shifter 112, respectively, and the logic processor 113 is configured to set a rising edge of the delayed pulse signal P' to a falling edge of the 1 pulse signal P to 0 to form the enable signal EN.

Illustratively, the motor 150 operates in a three-phase six-state, six input terminals of the or gate 111 are electrically connected to six output terminals of the freewheel pulse angle capturing circuit 170, and the or gate 111 can receive pulses generated during each phase change and perform an or operation on the pulses to form a pulse signal P, as shown in fig. 5. The amount of phase shift of the phase shifter 112 is set to 60 °, and the phase shifter 112 can receive the pulse signal P and delay the pulse signal P by 60 ° to form a delayed pulse signal P', as shown in fig. 5. The logic processor 113 can receive the pulse signal P and the delayed pulse signal P ', set the rising edge of the delayed pulse signal P' to 1, and set the falling edge of the pulse signal P to 0, to form the enable signal EN, as shown in fig. 5. The time when the enable signal EN is at a high level signal covers the commutation freewheel time, and the feedback quantity acquisition circuit 130 operates only when the enable signal EN is at a low level, that is, the operating time of the feedback quantity acquisition circuit 130 does not overlap with the commutation freewheel time, so that the influence of the freewheel on the integral can be avoided, and the commutation error can be reduced.

The embodiment of the present invention further provides a phase commutation method for a high-speed brushless dc motor, which is suitable for the phase commutation system 100 for a high-speed brushless dc motor provided in the above embodiment, and has the beneficial effects of the phase commutation system 100 for a high-speed brushless dc motor.

Fig. 7 is a flowchart illustrating a phase commutation method of a high-speed brushless dc motor according to an embodiment of the present invention, which is applied to the phase commutation system 100 of the high-speed brushless dc motor shown in fig. 1. As shown in fig. 7, the specific steps of the commutation method include:

and S110, forming a reconstructed suspended counter electromotive force according to the enable signal, the window signal, the three-phase terminal voltage and the neutral point voltage.

Illustratively, as shown in fig. 1, the enable signal generating circuit 110 outputs an enable signal, the window generating circuit 120 outputs a window signal, and the feedback amount acquiring circuit 130 operates under the effect of the enable signal, for example, the enable signal may be a low level signal, and the feedback amount acquiring circuit 130 operates under the effect of the low level signal. The window signal can select a specific window for the input signal, and output a signal of the window region, and the feedback quantity acquisition circuit 130 can determine to reconstruct the suspended counter electromotive force according to the a-phase terminal voltage, the B-phase terminal voltage, the C-phase terminal voltage, the neutral point voltage, and the window signal under the effect of the enable signal.

And S120, integrating the reconstructed suspended counter electromotive force in a period to obtain a feedback quantity.

Based on the above embodiment, after determining the reconstructed floating back electromotive force, the feedback quantity obtaining circuit 130 integrates the reconstructed floating back electromotive force in one period, and the integration result is the area S after the zero point moment in the period₂Area S before zero point time₁The feedback amount u 'S are shown in FIGS. 2 to 4'_rIs positively correlated with the area difference value Delta S, so that the feedback quantity u 'can be obtained'_r. For example: when the commutation is accurate, delta S is 0 and the feedback quantity u'_r0; at delayed commutation, Δ S>0, feedback quantity u'_r>0; when phase change is advanced, Δ S<0, feedback quantity u'_r<0。

And S130, generating a commutation signal according to the feedback quantity and the collected virtual Hall signal.

Specifically, the control circuit 140 can also be configured to output the feedback amount u'_rDetermining whether the phase change is accurate, lagged or advanced, and adjusting the A-phase virtual Hall signal Ha, the B-phase virtual Hall signal Hb and the C-phase virtual Hall line number Hc according to the determination to generate the A-phase commutation signal Sa, the B-phase commutation signal Sb and the C-phase commutation signal Sc so as to enable the feedback quantity u'_rTending to 0 and thereby reducing commutation errors.

According to the technical scheme provided by the embodiment of the invention, the construction of the reconstructed suspended counter electromotive force and the process of generating the feedback quantity by integration are realized by the hardware circuit, and the operation speed of the hardware circuit is high, so that the acquisition speed of the feedback quantity is high, the sampling frequency of the commutation system 100 can be improved, the accuracy of the integration quantity is improved, the commutation error is reduced, and the high-accuracy commutation of the motor is realized. In addition, since the hardware circuit performs operations such as sampling and integration, interrupt resources, analog-to-digital conversion resources, and calculation resources can be saved.

Optionally, fig. 8 is a flowchart illustrating a phase commutation method of another high-speed brushless dc motor according to an embodiment of the present invention, and when S110 is executed, the implementation manner shown in fig. 8 may be adopted, including:

and S111, acquiring three-phase back electromotive force according to the three-phase terminal voltage and the neutral point voltage.

In particular, according to the A-phase terminal voltage u_aAnd neutral point voltage u_nThe phase voltage u of phase A can be calculated_anAccording to the voltage u of the phase-B terminal_bAnd neutral point voltage u_nThe phase voltage u of the B phase can be calculated_bnAccording to the voltage u of the phase C terminal_cAnd neutral point voltage u_nThe C-phase voltage u can be calculated_cn. Phase voltage u of phase A_anEqual to A counter electromotive force e_aPhase voltage u of phase B_bnEqual to B counter electromotive force e_bPhase voltage u of C phase_cnEqual to C counter electromotive force e_c。

And S112, acquiring three-phase reverse electromotive force according to the three-phase reverse electromotive force.

In particular, the counter electromotive force e according to A_aCan obtain A opposite counter electromotive force-e_aAccording to B counter electromotive force e_bB opposite electromotive force-e can be obtained_bAccording to C, counter electromotive force e_cCan obtain the reverse electromotive force-e of C_c。

And S113, generating the reconstructed suspended counter electromotive force according to the enable signal, the window signal, the three-phase counter electromotive force and the three-phase reverse-phase counter electromotive force.

In particular, the electromotive force e is reversed by A_aB phase end counter electromotive force e_bC counter electromotive force e_cAnd A-direction reverse-phase counter electromotive force-e_aReverse phase counter electromotive force-e of B direction_bAnd C-direction reverse-phase counter electromotive force-e_cAnd selecting a voltage signal in the window to output in a working state as an object, and finally forming a reconstructed suspended counter electromotive force. The reconstruction of the suspended counter electromotive force breaks the suspended counter electromotive force along the edge e in the period_xDue to the axisymmetric relation, integral miscalculation caused by low sampling frequency is avoided, and the error of the feedback quantity is reduced, so that the commutation error is reduced.

Optionally, executing S120 includes:

calculating the feedback quantity u 'according to the following formula'_r：

Wherein u is_rFor the reconstruction of the suspended counter electromotive force, T is the period of the reconstructed suspended counter electromotive force, and T is time.

Specifically, in the above formula, the integration result of the integral formula is the area difference Δ S, and therefore the feedback amount u'_rIs the product of the area difference deltas and the factor 2/T. In the high-speed brushless DC motor, the period T is far less than 1, so the coefficient 2/T has amplification effect on the area difference value delta S and the feedback quantity u'_rThe phase change error can be more effectively controlled by amplifying the actual phase change error and more prominently displaying the phase change error when the phase change error is smaller. In addition, along with the increase of the rotating speed of the motor, the commutation error control is more accurate.

Optionally, fig. 9 is a schematic flowchart of a phase-changing method of a high-speed brushless dc motor according to another embodiment of the present invention, and when S130 is executed, the specific steps are as shown in fig. 9, and the method includes:

s131, the feedback analog quantity is converted into a feedback digital quantity.

Specifically, feedback quantity u'_rThe analog feedback quantity is an analog quantity, and the analog feedback quantity is required to be converted into a book word feedback quantity, so that a subsequent circuit can conveniently identify a feedback quantity signal, and correlation processing is facilitated.

And S132, determining a compensation phase according to the feedback digital quantity.

Specifically, the compensation phase is generated according to the following function

Where k is the gain factor, a is the attenuation factor, t is time, sgn is the step function, u "_rFor internally generated commands, if a feedback digital quantity of 1, u is received "_r1 ═ 1; if the received feedback digital quantity is 0, u "_r＝-1。

If the commutation is delayed, the feedback quantity u'_r>0, feedback digital quantity 1, u "_rCompensating for phase +1If the commutation phase is advanced, the feedback quantity u'_r<0, feedback digital quantity is 0, u "_rCompensating for phase 1Thus, respective compensation phases are generated according to the phase change lead or lag.

And S133, compensating the virtual Hall signal according to the compensation phase to generate the commutation signal.

Illustratively, when the commutation is delayed,so that the phases of the A-phase commutation signal Sa, the B-phase commutation signal Sb and the C-phase commutation signal Sc are shifted forward compared with the phases of the A-phase virtual Hall signal Ha, the B-phase virtual Hall signal Hb and the C-phase virtual Hall signal Hc, thereby making the feedback amount u'_rTending to 0. When the phase-change is advanced, the phase-change is carried out,so that the phases of the a-phase commutation signal Sa, the B-phase commutation signal Sb, and the C-phase commutation signal Sc are shifted backward as compared with the phases of the a-phase virtual hall signal Ha, the B-phase virtual hall signal Hb, and the C-phase virtual hall line signal Hc, thereby making Δ S tend to 0. Therefore, the phase shifter 143 can compensate the phase according to the compensated phaseAdjusting the A-phase virtual Hall signal Ha, the B-phase virtual Hall signal Hb and the C-phase virtual Hall signal Hc to make the feedback quantity u'_rTending to 0.

Optionally, fig. 10 is a schematic flowchart of a phase commutation method of a high-speed brushless dc motor according to another embodiment of the present invention, and before executing S110, as shown in fig. 10, the method further includes:

and S210, acquiring a pulse corresponding to the free-wheeling time and generating a pulse signal.

Specifically, a voltage peak value appears in the commutation follow current time in the commutation process, in the high-speed brushless direct current motor, the proportion of the follow current time width in a period is large, the follow current time width cannot be ignored, and pulses in the follow current time are not beneficial to accurate calculation of integral of reconstruction of suspended counter electromotive force in the period. And acquiring corresponding pulses in the commutation follow current time during each commutation, and carrying out OR operation on the pulses to form a pulse signal P so as to avoid the influence of the pulses in the follow current time on integration in the follow-up process.

And S220, delaying the pulse signal by 60 degrees to form a delayed pulse signal.

And S230, setting the rising edge of the delay pulse signal to be 1 and the falling edge of the pulse signal to be 0 to form the enable signal.

Specifically, the pulse signal P is delayed by 60 ° to form a delayed pulse signal P ', the rising edge of the delayed pulse signal P' is set to 1, and the falling edge of the pulse signal P is set to 0, to form an enable signal EN, as shown in fig. 5. The time when the enable signal EN is at a high level signal covers the commutation freewheel time, and the feedback quantity acquisition circuit 130 operates only when the enable signal EN is at a low level, that is, the operating time of the feedback quantity acquisition circuit 130 does not overlap with the commutation freewheel time, so that the influence of the freewheel on the integral can be avoided, and the commutation error can be reduced.

It is noted that, in this document, relational terms such as "first" and "second," and the like, may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The foregoing are merely exemplary embodiments of the present disclosure, which enable those skilled in the art to understand or practice the present disclosure. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.