阅读说明：本技术 无刷直流电机高精度换相控制的方法及系统 (Brshless DC motor high-precision changes facies-controlled method and system ) 是由 尤钱亮 魏海峰 张懿 李震 李可礼 李垣江 刘维亭 王浩陈 于 2019-08-27 设计创作，主要内容包括：本发明公开了一种无刷直流电机高精度换相控制的方法及系统,包括：以预设采样周期获取三相定子绕组的反电动势数值,并记录三相定子绕组的反电动势数值；当时三相定子绕组的反电动势数值产生过零现象时,通过判断产生过零现象的一相定子绕组反电动势的上一次采样周期数值与0、第一对比值以及第二对比值的关系,确定是否为假过零点；如果是假过零点则执行弱化消磁,否则执行换相。本发明可准确判断无刷直流电机换相点,缓解无刷直流电机换相期间非切换相续流产生端电压脉冲而引发转矩脉动的影响,提高无刷直流电机换相控制性能。(The invention discloses a kind of brshless DC motor high-precisions to change facies-controlled method and system, comprising: obtains the counter electromotive force numerical value of threephase stator winding to preset the sampling period, and records the counter electromotive force numerical value of threephase stator winding；When the counter electromotive force numerical value of threephase stator winding generates zero passage phenomenon at that time, the last sampling period numerical value of a phase stator winding counter electromotive force of zero passage phenomenon and the relationship of the 0, first reduced value and the second reduced value are generated by judgement, it is determined whether be false zero crossing；Reduction demagnetization is then executed if it is false zero crossing, otherwise executes commutation.The present invention can accurate judgement brshless DC motor commutation point, non-switching sequentially miscarriage causes trouble voltage pulse and causes the influence of torque pulsation during alleviating brshless DC motor commutation, improves brshless DC motor commutation control performance.)

1. a kind of brshless DC motor high-precision changes facies-controlled method, which comprises the steps of:

Step 1: setting the first reduced value, the second reduced value, to preset the counter electromotive force that the sampling period obtains threephase stator winding Numerical value, and record the counter electromotive force numerical value of threephase stator winding；

Step 2: the counter electromotive force numerical value for judging whether there is a phase stator winding generates zero passage phenomenon and holds when there is zero passage phenomenon Row step 3；When there is no zero passage phenomenon, step 1 is executed；

Step 3: judge what the phase stator winding that zero passage phenomenon is generated in the step 2 obtained in upper one default sampling period Whether counter electromotive force numerical value is greater than 0；

When being greater than 0, judge that the phase stator winding that zero passage phenomenon is generated in the step 2 obtains in upper one default sampling period Whether the counter electromotive force numerical value taken is greater than the first reduced value, when being greater than the first reduced value, executes reduction demagnetization and acts and return Step 1；When being not more than the first reduced value, commutation movement is executed；

When less than 0, judge that the phase stator winding that zero passage phenomenon is generated in the step 2 obtains in upper one default sampling period Whether the counter electromotive force numerical value taken is less than the second reduced value, when less than the second reduced value, executes reduction demagnetization and acts and return Step 1；When being not more than the second reduced value, commutation movement is executed.

2. brshless DC motor high-precision according to claim 1 changes facies-controlled method, which is characterized in that the three-phase The counter electromotive force of stator winding is obtained by the end voltage of real-time detection threephase stator winding.

3. brshless DC motor high-precision according to claim 1 changes facies-controlled method, which is characterized in that described default Sampling period is 10 μ s to 20 μ s.

4. brshless DC motor high-precision according to claim 1 changes facies-controlled method, which is characterized in that described first The value range of reduced value is the 10%~20% of brshless DC motor voltage rating, and the value range of second reduced value is - 10%~-the 20% of brshless DC motor voltage rating.

5. brshless DC motor high-precision according to claim 1 changes facies-controlled method, which is characterized in that the step The specific method is as follows for reduction demagnetization movement in three:

It sets the PWM duty cycle of the non-switching corresponding upper bridge arm power device of the inverter in a upper commutation process to Duty ratio is reverted into D after 100%, t seconds.

6. brshless DC motor high-precision according to claim 5 changes facies-controlled method, which is characterized in that the t= 1/ ω, wherein ω is motor speed, and the unit of unit r/min, t are s.

7. brshless DC motor high-precision according to claim 5 or 6 changes facies-controlled method, which is characterized in that the D For when PID controller is input with the error of the setting value of rotor speed and the actual value of rotor speed the duty ratio that exports it is defeated It is worth out.

8. a kind of brshless DC motor high-precision changes facies-controlled system characterized by comprising

Detection module, comparison module, pid control module, reduction demagnetization module, commutation module, inverter；

The detection module is connected with the threephase stator winding and the comparison module respectively, for detecting A phase, B phase and C The end voltage of phase stator winding obtains the counter electromotive force of A phase, B phase and C phase stator winding, and will test result be transmitted to it is described Comparison module；

The comparison module respectively with the reduction demagnetization module and the commutation module, for the one of zero passage phenomenon will to be generated Phase stator winding last time preset the sampling period obtain counter electromotive force numerical value and 0 and first reduced value or with 0 and second pair Ratio compares, and executes speak demagnetization or commutation according to comparison result；

The pid control module is connected with the reduction demagnetization module, for the setting value of rotor speed and rotor speed The error of actual value is that input carrys out output duty cycle D；

The reduction demagnetization module is connected with the inverter, for the output signal and pid control module according to comparison module Output signal, control the PWM duty cycle of the non-switching corresponding upper bridge arm metal-oxide-semiconductor of inverter, shortening is when being not turned on phase afterflow Between；

The commutation module is connected with the inverter, for commutation needed for being executed according to the output signal of comparison module；

The inverter is connected with the threephase stator winding, for driving the A phase, B phase and C phase stator winding.

Technical field

The present invention relates to brshless DC motor technical fields, and in particular to a kind of brshless DC motor high-precision commutation control Method and system.

Background technique

Brshless DC motor is widely used in scientific instrument, industrial equipment and electric vehicle, has structure simple, efficiency High advantage.Hall sensor, photoelectric encoder and rotary transformer are typically used to provide brshless DC motor commutation information, but Its precision is easy to be influenced by external environment and installation accuracy.Therefore, the research pair of brshless DC motor sensorless drive It is of great significance in industrial application and scientific research.

Counter electromotive force method is the most frequently used, simplest method in position-sensor-free technology, passes through sampling end voltage or line The zero crossing of voltage difference generates the commutation position signal of brshless DC motor, realizes the normal operation of brshless DC motor.But Be, when brshless DC motor revolving speed be greater than rated speed 80% or, person load be greater than nominal load 20% when, do not led during commutation Logical phase afterflow can generate end voltage pulse, and causing vacation to cross null event influences the normal driving of motor so that commutation point shifts to an earlier date.Together When, commutation current overlong time can cause biggish torque pulsation.

It is that false zero crossing is avoided by the detection that is delayed mostly in existing method, torque pulsation is reduced by complicated algorithm, Such algorithm is generally computationally intensive, higher to processing unit performance requirement.The present invention can accurate judgement brshless DC motor commutation Time, shortening are not turned on phase time of afterflow, improve system stability, and algorithm is simple and reliable, require processing unit low, easy behaviour Make.

Summary of the invention

The present invention provides a kind of brshless DC motor high-precisions to change facies-controlled method and system, to solve brushless direct-current Voltage pulse of causing trouble of sequentially miscarrying is not turned on during motor commutation, causing vacation to cross null event influences motor so that commutation point shifts to an earlier date Normal driving and be not turned on the problem of phase afterflow overlong time causes larger torque pulsation.

The present invention provides a kind of brshless DC motor high-precisions to change facies-controlled method, comprising:

Step 1: setting the first reduced value, the second reduced value, to preset the anti-electricity that the sampling period obtains threephase stator winding Kinetic potential numerical value, and record the counter electromotive force numerical value of threephase stator winding；

Step 2: the counter electromotive force numerical value for judging whether there is a phase stator winding generates zero passage phenomenon, when there is zero passage phenomenon When, execute step 3；When there is no zero passage phenomenon, step 1 is executed；

Step 3: judge that the phase stator winding that zero passage phenomenon is generated in the step 2 obtains in upper one default sampling period Whether the counter electromotive force numerical value taken is greater than 0；

When being greater than 0, judge the phase stator winding for generating zero passage phenomenon in the step 2 in upper one default sampling week Whether the counter electromotive force numerical value that the phase obtains is greater than the first reduced value, when being greater than the first reduced value, executes reduction demagnetization movement simultaneously Return step one；When being not more than the first reduced value, commutation movement is executed；

When less than 0, judge the phase stator winding for generating zero passage phenomenon in the step 2 in upper one default sampling week Whether the counter electromotive force numerical value that the phase obtains is less than the second reduced value, when less than the second reduced value, executes reduction demagnetization movement simultaneously Return step one；When being not more than the second reduced value, commutation movement is executed.

Further, the counter electromotive force of the threephase stator winding is obtained by the end voltage of real-time detection threephase stator winding It arrives.

Further, the default sampling period is 10 μ s to 20 μ s.

Further, the value range of first reduced value is the 10%~20% of brshless DC motor voltage rating, The value range of second reduced value is -10%~- the 20% of brshless DC motor voltage rating.

Further, the specific method is as follows for the reduction demagnetization movement in the step 3:

It sets the PWM duty cycle of the non-switching corresponding upper bridge arm power device of the inverter in a upper commutation process to Duty ratio is reverted into D after 100%, t seconds.

Further, the t=1/ ω, wherein ω is motor speed, and the unit of unit r/min, t are s.

Further, the D is when PID controller is with the error of the setting value of rotor speed and the actual value of rotor speed Duty ratio output valve when to input.

A kind of brshless DC motor high-precision changes facies-controlled system characterized by comprising

Detection module, comparison module, pid control module, reduction demagnetization module, commutation module, inverter；

The detection module is connected with the threephase stator winding and the comparison module respectively, for detecting A phase, B Mutually with the end voltage of C phase stator winding, the counter electromotive force of A phase, B phase and C phase stator winding is obtained, and will test result and be transmitted to The comparison module；

The comparison module with the reduction demagnetization module and the commutation module, is used to that zero passage phenomenon will to be generated respectively A phase stator winding last time preset counter electromotive force numerical value and 0 and the first reduced value that the sampling period obtains or with 0 and the Two reduced values compare, and execute speak demagnetization or commutation according to comparison result；

The pid control module is connected with the reduction demagnetization module, for being turned with the setting value of rotor speed and rotor The error of the actual value of speed is that input carrys out output duty cycle D；

The reduction demagnetization module is connected with the inverter, for the output signal and PID control according to comparison module The output signal of module, controls the PWM duty cycle of the non-switching corresponding upper bridge arm metal-oxide-semiconductor of inverter, and shortening is not turned on sequentially Flow the time；

The commutation module is connected with the inverter, for commutation needed for being executed according to the output signal of comparison module；

The inverter is connected with the threephase stator winding, for driving the A phase, B phase and C phase stator winding.

Beneficial effects of the present invention:

1, since false zero passage phenomenon is impulse waveform, high level is mutated by low level or low electricity is mutated by high level It is flat, it will not continue under low level and high level state, be a kind of instantaneous state；And true zero passage phenomenon, to undergo low electricity High level or high level are put down to low level progressive formation, is a kind of process status.According to above-mentioned characteristic, by occurring The comparison of the numerical value and default fiducial value of one Xiang Shangyi collection period of zero phenomenon, judges the validity of zero crossing, to avoid Influence of the false zero passage phenomenon to commutation, completes the accurate commutation of brshless DC motor.

2, by being eliminated the dump energy of non-switching phase using power device afterflow, to reduce brshless DC motor commutation Period is not turned on phase afterflow and the width of end voltage pulse that generates, shortens time of afterflow, alleviates the too long initiation of time of afterflow The influence that torque pulsation drives brshless DC motor improves system stability.

Detailed description of the invention

The features and advantages of the present invention will be more clearly understood by referring to the accompanying drawings, and attached drawing is schematically without that should manage Solution is carries out any restrictions to the present invention, in the accompanying drawings:

Fig. 1 changes facies-controlled method flow diagram for brshless DC motor high-precision a kind of in the embodiment of the present invention；

Fig. 2 is a kind of main circuit diagram of BLDCM Drive System in the embodiment of the present invention；

Fig. 3 is brshless DC motor equivalent circuit diagram in the embodiment of the present invention；

Fig. 4 is three-phase stator winding back emf waveform figure in the embodiment of the present invention；

Fig. 5 is a kind of brshless DC motor high-precision commutation control system architecture figure in the embodiment of the present invention.

Specific embodiment

In order to make the object, technical scheme and advantages of the embodiment of the invention clearer, below in conjunction with the embodiment of the present invention In attached drawing, technical scheme in the embodiment of the invention is clearly and completely described, it is clear that described embodiment is A part of the embodiment of the present invention, instead of all the embodiments.Based on the embodiments of the present invention, those skilled in the art are not having Every other embodiment obtained under the premise of creative work is made, shall fall within the protection scope of the present invention.

The embodiment of the invention provides a kind of brshless DC motor high-precisions to change facies-controlled method, as shown in Figure 1, packet It includes:

Step S1: to preset the counter electromotive force numerical value that the sampling period obtains threephase stator winding.

Step S2: the counter electromotive force numerical value of threephase stator winding is recorded.

Since stator winding pressure drop is smaller, so ignore the resistance value of stator winding, the counter electromotive force of threephase stator winding It is approximately equal to the end voltage of each phase stator winding.The anti-of threephase stator winding is obtained by the end voltage of the sub- winding of real-time detection three-phase Electromotive force, and record.

Step S3: whether judge has the counter electromotive force numerical value of a phase stator winding to generate zero passage in threephase stator winding shows As executing step S4 when there is zero passage phenomenon；When there is no zero passage phenomenon, executes step S1 and continue to supervise zero passage phenomenon Depending on；

Step S4: judge generate zero passage phenomenon a phase stator winding counter electromotive force last sampling period numerical value whether Greater than 0, when last sampling period numerical value is greater than 0, step S5 is executed；When last sampling period numerical value is no more than 0 When, execute step S6.

Step S5: judge generate zero passage phenomenon a phase stator winding counter electromotive force last sampling period numerical value whether Greater than the first reduced value, when last sampling period numerical value is greater than the first reduced value, then reduction demagnetization movement is executed；When upper one When secondary sampling period numerical value is not more than the first reduced value, then commutation is executed.

Step S6: judge generate zero passage phenomenon a phase stator winding counter electromotive force last sampling period numerical value whether Less than the second reduced value, when last sampling period numerical value is less than the second reduced value, reduction demagnetization movement is executed；Work as the last time When sampling period numerical value is not less than the second reduced value, commutation is executed.

Since false zero passage phenomenon is impulse waveform, high level is mutated by low level or low electricity is mutated by high level It is flat, it will not continue under low level and high level state, be a kind of instantaneous state；And true zero passage phenomenon, to undergo low electricity High level or high level are put down to low level progressive formation, is a kind of process status.So false zero passage phenomenon and true mistake Numerical value of both zero phenomenons in the previous sampling period that zero passage generates has apparent difference, is passed through according to this characteristic pre- If reduced value, it can be determined that whether effective go out zero crossing.

As shown in Fig. 2, being the circuit structure diagram of inverter, and the connection relationship of inverter and threephase stator winding is shown.

Stator winding is periodically powered on the power-up sequence of table 1, the forward direction that brshless DC motor may be implemented is changed Mutually drive.Table 1 also shows corresponding energized state and metal-oxide-semiconductor conducting situation under each power-up sequence.

Table 1

The movement of reduction demagnetization at this time is exactly that the PWM duty cycle of the non-switching corresponding upper bridge arm metal-oxide-semiconductor of inverter is arranged Duty ratio is reverted into D after being 100%, 1/ ω seconds.

If stator winding will be conducted from A phase, B, commutation is conducted to A phase, C, and the non-switching phase of inverter is A phase, corresponding Upper bridge arm metal-oxide-semiconductor be T1；If stator winding will be conducted from A phase, C, commutation is conducted to B phase, C, the non-switching phase of inverter For C phase, corresponding upper bridge arm metal-oxide-semiconductor is T5；If stator winding will be conducted from B phase, C, commutation is conducted to A phase, B, inversion The non-switching phase of device is B phase, and corresponding upper bridge arm metal-oxide-semiconductor is T3.

Duty ratio D is adjusted to obtain by PID.The PID controller is with the actual value of the setting value of rotor speed and rotor speed Error be input, be output with duty ratio D, duty ratio D can brushless motor speed reach desired target to turn at this time Speed, specific formula is as follows:

Wherein, k_pFor the proportionality coefficient of PID controller, in order to which system response time is fast, overshoot is smaller, proportionality coefficient selection 0.5；T_iFor the integration time constant of PID controller, in order to which speed convergence speed is shorter, integration time constant selection 0.2；T_dFor The derivative time constant of PID controller, but the introducing of differential will lead to velocity fluctuation, therefore it is set to 0；ω_refFor setting for rotor speed Definite value；ω_eFor the actual value of rotor speed；K is duty ratio transformation ratio, and numerical value is 1/ ω₀, ω₀It is specified for brshless DC motor Revolving speed, because of duty ratio and torque direct proportionality, K is 1/ ω₀。

As shown in figure 3, being brshless DC motor equivalent circuit diagram, it is as follows that stator winding three-phase current can be solved according to Fig. 3

Wherein, i_A、i_B、i_CThe respectively electric current of A, B, C threephase stator winding；I₀For phase current peak value；k_eω_mIt is anti-electronic Potential hump value；H is duty ratio；V_DCFor busbar voltage；R is equivalent phase resistance；L is equivalent phase inductance；e_A、e_B、e_CRespectively A, B, C The counter electromotive force of threephase stator winding.From formula as can be seen that H is bigger, the pace of change of three-phase current is bigger, then when afterflow Between it is shorter.Therefore, since the zero crossing of end voltage pulse for being not turned on phase, by the non-switching corresponding upper bridge arm of inverter The PWM duty cycle of metal-oxide-semiconductor be set as 100% and maintain 1/ ω second, can chopped pulse width, reduce time of afterflow, alleviate do not lead Logical influence of the phase afterflow overlong time to direct torque.ω is motor speed, unit r/min.

In the present embodiment, the counter electromotive force of threephase stator winding is measured in real time.The value model of first reduced value Enclosing is the 10%~20% of brshless DC motor voltage rating, preferably 15%, and the value range of the second reduced value is brushless direct-current - the 10% of Rated motor voltage~-20%, preferably -15%.For adaptability of the reduced value under different rotating speeds, selection 15%, -15% the first reduced value, the second reduced value are used as.

As shown in figure 4, E_A is A phase back-emf figure, E_B is B phase back-emf figure, E_C is C phase back-emf figure, I For the first reduced value, II is the second reduced value.

When passing to positive current from A phase stator winding, the state of negative current, commutation to A phase stator are passed to B phase stator winding Winding leads to positive current, and after the state of negative current is led to C phase stator winding, B phase stator winding may generate afterflow, from table 1 In see the afterflow be possible to from A phase stator winding lead to positive current, to C phase stator winding lead to negative current state, commutation to B False zero passage phenomenon is generated when phase stator winding passes to positive current, C phase stator winding passes to negative current, will appear if not handling Commutation in advance.B phase back-emf figure E_B in Fig. 4 is that the B after being powered with 1 power-up sequence of table to threephase stator winding is electric on the contrary The waveform diagram of kinetic potential, wherein a point is a zero crossing of B phase back-emf, when system detection is to the zero crossing, is temporarily ceased To the real-time detection of counter electromotive force, at this time from figure the last sampling period numerical value of B phase stator winding counter electromotive force less than 0 And less than the second reduced value, be judged as false zero passage phenomenon, the phenomenon may be before commutation cutting B phase stator winding electrifying when B Caused by the afterflow generated in phase stator winding, by the corresponding upper bridge arm metal-oxide-semiconductor of A phase stator winding in inverter, i.e. in Fig. 2 The PWM duty cycle of metal-oxide-semiconductor T1 is set as that duty ratio is reverted to D after 100%, 1/ ω seconds, eliminates B by reduction demagnetization movement Afterflow in phase stator winding, weaken demagnetization after system continue real-time detection threephase stator winding counter electromotive force, when system again The secondary back electromotive force zero-crossing detected on B phase stator winding, i.e. b point in Fig. 4, temporarily ceases the real-time inspection to counter electromotive force Survey, at this time from figure the last sampling period numerical value of B phase stator winding counter electromotive force less than 0 and be greater than the second reduced value, It is judged as true zero passage phenomenon, executes commutation operation, stator winding is led into positive current, C phase stator winding from A phase stator winding Logical negative current commutation to B phase stator winding leads to positive current, C phase stator winding leads to negative current, and anti-electricity is issued after the completion of commutation operation Kinetic potential detects signal, continues the counter electromotive force of real-time detection threephase stator winding.

When passing to positive current from A phase stator winding, the state of negative current, commutation to B phase stator are passed to C phase stator winding Winding leads to positive current, and after the state of negative current is led to C phase stator winding, A phase stator winding may generate afterflow, from table 1 In see the afterflow be possible to from B phase stator winding lead to positive current, to C phase stator winding lead to negative current state, commutation to B False zero passage phenomenon is generated when phase stator winding passes to positive current, A phase stator winding passes to negative current, will appear if not handling Commutation in advance.A phase back-emf figure E_A in Fig. 4 is that the A after being powered with 1 power-up sequence of table to threephase stator winding is electric on the contrary The waveform diagram of kinetic potential, wherein c point is a zero crossing of A phase back-emf, when system detection is to the zero crossing, is temporarily ceased To the real-time detection of counter electromotive force.The last sampling period numerical value of A phase stator winding counter electromotive force is greater than 0 from figure at this time And be greater than the first reduced value, be judged as false zero passage phenomenon, the phenomenon may be before commutation cutting A phase stator winding electrifying when A Caused by the afterflow generated in phase stator winding, by the corresponding upper bridge arm metal-oxide-semiconductor of C phase stator winding in inverter, i.e. in Fig. 2 The PWM duty cycle of metal-oxide-semiconductor T1 is set as that duty ratio is reverted to D after 100%, 1/ ω seconds, and the PWM duty cycle for accounting for metal-oxide-semiconductor T5 is set It is set to after 100%, 1/ ω seconds and duty ratio is reverted into D, the afterflow in A phase stator winding is eliminated by reduction demagnetization movement, System continues the counter electromotive force of real-time detection threephase stator winding after reduction demagnetization, when system detects A phase stator winding again On back electromotive force zero-crossing, i.e. d point in Fig. 4, system temporarily ceases the real-time detection to counter electromotive force.A phase stator winding The last sampling period numerical value of counter electromotive force is greater than 0 and less than the first reduced value, then executes commutation operation, by stator winding from B phase stator winding leads to positive current, C phase stator winding leads to negative current commutation to B phase stator winding and leads to positive current, A phase stator winding Logical negative current issues counter electromotive force after the completion of commutation operation and detects signal, continues the anti-electronic of real-time detection threephase stator winding Gesture.

In Fig. 4 e point to l point manner of execution, with above-mentioned processing method.

As shown in figure 5, the present invention also provides a kind of brshless DC motor high-precisions to change facies-controlled system, comprising:

Detection module, comparison module, pid control module, reduction demagnetization module, commutation module, inverter；

Detection module is connected with threephase stator winding and comparison module respectively, for detect A phase, B phase and C phase stator around The end voltage of group, obtains the counter electromotive force of A phase, B phase and C phase stator winding, and will test result and be transmitted to comparison module；

Comparison module respectively with reduction demagnetization module and commutation module, for will generate a phase stator of zero passage phenomenon around Group last time presets counter electromotive force numerical value that the sampling period obtains and 0 and first reduced value or with 0 and second compared with reduced value, Speak demagnetization or commutation are executed according to comparison result；

Pid control module is connected with reduction demagnetization module, for the reality of the setting value of rotor speed and rotor speed The error of value is that input carrys out output duty cycle D；

Reduction demagnetization module is connected with inverter, for according to the defeated of the output signal of comparison module and pid control module Signal out, controls the PWM duty cycle of the non-switching corresponding upper bridge arm metal-oxide-semiconductor of inverter, and shortening is not turned on phase time of afterflow；

Commutation module is connected with inverter, for commutation needed for being executed according to the output signal of comparison module；

Inverter is connected with threephase stator winding, for driving A phase, B phase and C phase stator winding.

Although being described in conjunction with the accompanying the embodiment of the present invention, those skilled in the art can not depart from the present invention Spirit and scope in the case where various modifications and variations can be made, such modifications and variations are each fallen within by appended claims institute Within the scope of restriction.