阅读说明：本技术 一种基于非对称脉宽调制的方波电压注入方法 (A kind of square-wave voltage method for implanting based on asymmetric pulse widths modulation ) 是由 陈哲 张航 王逸衍 刘卫国 于 2019-08-23 设计创作，主要内容包括：本发明涉及一种基于非对称脉宽调制的方波电压注入方法,针对低开关频率下传统正弦电压注入法存在的高频响应电流畸变、载波次谐波倍频和边带谐波低次化等问题,提出一种基于非对称空间矢量脉宽调制来实现方波电压注入的无位置传感器控制方法：选择方波电压作为注入谐波,免除位置估计环节大量滤波器的使用,简化高频信号处理过程；采用非对称空间矢量脉宽调制(ASVM)方法,消除低阶边带谐波和基带谐波,减少高频响应电流信号重叠。实验结果表明,基于ASVM的方波电压注入法在低开关频率下有效降低了高频响应电流中的无效谐波成分干扰,提高了转子位置估计性能。(The present invention relates to a kind of square-wave voltage method for implanting based on asymmetric pulse widths modulation, the problems such as high frequency response current distortion existing for conventional sinusoidal voltage injection method under low switching frequency, carrier wave subharmonic frequency multiplication and sideband harmonic wave low order, it proposes a kind of method for controlling position-less sensor for realizing square-wave voltage injection based on asymmetric space vector pulse width modulation: selecting square-wave voltage as harmonic, exempt the use of a large amount of filters of location estimation link, simplifies high frequency signals process；Using asymmetric space vector pulse width modulation (ASVM) method, low order sideband harmonic wave and base-band harmonics are eliminated, reduce the overlapping of high frequency response current signal.The experimental results showed that the square-wave voltage injection method based on ASVM effectively reduces the interference of the invalid harmonic components in high frequency response electric current under low switching frequency, rotor position estimate performance is improved.)

1. a kind of square-wave voltage method for implanting based on asymmetric pulse widths modulation, it is characterised in that steps are as follows:

Step 1: injecting square wave voltage signal to estimation d axis when motor is static, ac-dc axis electricity is exported by PI current regulator Press U_dAnd U_q；

The square wave voltage signal are as follows:

In formula, symbol " ∧ " represents the estimated value of corresponding amount, U_hFor the amplitude for injecting square-wave voltage, injected frequency ω_hIt is set on Close the half of frequency；

Step 2: after electric motor starting, α, β axis high frequency response electric current are obtained by BPF filtering:

In formula, i_α、i_βFor actual α, β shaft current,For filtered α, β axis high frequency response electric current；

Step 3: calculating the envelope I of α, β axis high frequency response electric current_cos、I_sin:

In formula,θ_rFor true rotor-position,Go out for position detection unit estimation Rotor-position, Δ i_αhWith Δ i_βhFor the high frequency response current differential of two neighboring sampled point；L_dhAnd L_qhFor motor d under high frequency, Q axle inductance；

Step 4: obtain estimated location and estimation revolving speed:

Rotor position estimation value

Turn count value

In formula,As the input of position detection unit, K_p、K_iAnd K_dThe respectively design parameter of position detection unit；

It is describedWherein:

It is describedWherein: a < 0, J are motor rotary inertia；

Step 5: the rotor-position of estimation participates in coordinate transform, obtains α, β shaft voltage:

In formula, with u_α、u_βThe input that link is generated as pulse, obtains three-phase modulations wave by space vector pulse width modulation mode Signal u_A,u_B,u_C:

Wherein:

Step 6: in a carrier cycle T_s1/4 and 3/4 to superposition square-wave signal after three-phase modulations wave u_A,u_B,u_CRespectively Double sampling is carried out, remembers that the sampled value of forward and backward half period is respectively u_A1,u_B1,u_C1,u_A2,u_B2,u_C2；

Step 7: calculating equivalent modulated signal u_AM,u_BM,u_CM:

In first half cycle are as follows:

In the later half period are as follows:

Step 8: calculate each bridge arm switch state of IGBT:

u_AM>u_c,S_A=0

u_AM≤u_c,S_A=1

u_BM>u_c,S_B=0

u_BM≤u_c,S_B=1

u_BM>u_c,S_B=0

u_BM≤u_c,S_B=1

In formula, S_A,S_B,S_CFor the switch motion of each phase bridge arm, indicate that bridge arm IGBT is open-minded on corresponding bridge arm when being 1, lower bridge arm IGBT shutdown, 0 indicates its shutdown, and corresponding lower bridge arm is open-minded, u_cFor carrier wave.

Technical field

The invention belongs to permanent magnet synchronous motor method for controlling position-less sensor, are related to a kind of based on asymmetric pulse widths modulation Square-wave voltage method for implanting, be a kind of to realize that square wave is electric based on asymmetric space vector pulse width modulation under low switching frequency The rotor position estimate method that pressure injection enters, belongs to variable frequency ac drive technical field.

Background technique

Permanent magnet synchronous motor is because of the advantages that high-efficient, power density are big and wide speed regulating range, in recent years by rail traffic The close attention of industry.Due to being integrated with traction electric machine, rugged environment causes the failure rate of position sensor higher always, Cause the safety problems such as broken, the reduction of speed traveling of machine.Position Sensorless Control is to solve the problems, such as this key technology.However, with Other industrial applications are compared, and the switching device of bullet train inverter is limited by switching loss and heat dissipation, highest switching frequency It is usually no more than 1kHz.To make electric current have better harmonic performance and symmetrical feature, traction invertor is in low switch frequency at present Mixing pulsewidth modulation is generallyd use under rate: low speed segment uses asynchronous modulation method, and high regime uses particular harmonic elimination approach (SHEPWM), more than specified fast section square-wave frequency modulation method is used.Wherein, the switching frequency in asynchronous modulation area is typically not greater than 500Hz will appear carrier wave subharmonic frequency multiplication using Traditional Space Vector Modulation (SVM) method and sideband be humorous in this case The problem of wave low order.At the same time, low-order harmonic cannot be filtered completely by bandpass filter (BPF) in high frequency signals It removes, filtering signal is caused to be overlapped, impact position estimated accuracy.Due to the above reasons, based on high frequency electrocardiography without sensor Control program is restricted in the extensive use of field of track traffic.On the other hand, traditional sinusoidal voltage injection method is in high frequency It needs use compared with multi-filter when signal demodulation location estimation, can greatly limit the bandwidth of electric current loop and speed ring, and switch Since sampling number is less when frequency is lower, serious distortion can occur for sine voltage signal, and response current is caused to distort.And The form of square wave voltage signal determines its harmonic injection being more applicable under low switching frequency.

Currently, both at home and abroad about the research of permanent magnet synchronous motor position Sensorless Control be concentrated mainly on switching frequency compared with In the case where height, and tradition SVM asynchronous modulation method is still applied under low switching frequency, there is no analyze and solve tradition SVM The problem of method bring low-order harmonic aggravates.

Traditional method for controlling position-less sensor can have following two specific question under low switching frequency: 1) sinusoidal letter It number will appear serious distortion since sampled point is very few under low sample frequency, high frequency response signal caused Severe distortion occur.2) The problem of carrier wave subharmonic frequency multiplication and sideband harmonic wave low order will appear using Traditional Space Vector Modulation (SVM) method.

Summary of the invention

Technical problems to be solved

In order to avoid the shortcomings of the prior art, the present invention proposes a kind of square-wave voltage based on asymmetric pulse widths modulation On the one hand method for implanting selects square-wave voltage as harmonic, simplifies high frequency signals process.On the other hand using non- Symmetric space Vector Pulse Width Modulation (ASVM) method eliminates low order sideband harmonic wave and base-band harmonics, reduces high-frequency current signal weight It is folded.

Technical solution

A kind of square-wave voltage method for implanting based on asymmetric pulse widths modulation, it is characterised in that steps are as follows:

Step 1: injecting square wave voltage signal to estimation d axis when motor is static, handed over by the output of PI current regulator straight Shaft voltage U_dAnd U_q；

The square wave voltage signal are as follows:

In formula, symbol " ∧ " represents the estimated value of corresponding amount, U_hFor the amplitude for injecting square-wave voltage, injected frequency ω_hSetting For the half of switching frequency；

Step 2: after electric motor starting, α, β axis high frequency response electric current are obtained by BPF filtering:

In formula, i_α、i_βFor actual α, β shaft current,For filtered α, β axis high frequency response electric current；

Step 3: calculating the envelope I of α, β axis high frequency response electric current_cos、I_sin:

In formula,θ_rFor true rotor-position,Estimate for position detection unit The rotor-position counted out, Δ i_αhWith Δ i_βhFor the high frequency response current differential of two neighboring sampled point；L_dhAnd L_qhIt is electric under high frequency Machine d, q axle inductance；

Step 4: obtain estimated location and estimation revolving speed:

Rotor position estimation value

Turn count value

In formula,As the input of position detection unit, K_p、K_iAnd K_dThe respectively design parameter of position detection unit；

It is describedWherein:

It is describedWherein: a < 0, J are motor rotary inertia；

Step 5: the rotor-position of estimation participates in coordinate transform, obtains α, β shaft voltage:

In formula, with u_α、u_βThe input that link is generated as pulse, obtains three-phase tune by space vector pulse width modulation mode Wave signal u processed_A,u_B,u_C:

Wherein:

Step 6: in a carrier cycle T_s1/4 and 3/4 to superposition square-wave signal after three-phase modulations wave u_A,u_B,u_C Double sampling is carried out respectively, remembers that the sampled value of forward and backward half period is respectively u_A1,u_B1,u_C1,u_A2,u_B2,u_C2；

Step 7: calculating equivalent modulated signal u_AM,u_BM,u_CM:

In first half cycle are as follows:

In the later half period are as follows:

Step 8: calculate each bridge arm switch state of IGBT:

u_AM>u_c,S_A=0

u_AM≤u_c,S_A=1

u_BM>u_c,S_B=0

u_BM≤u_c,S_B=1

u_BM>u_c,S_B=0

u_BM≤u_c,S_B=1

In formula, S_A,S_B,S_CFor the switch motion of each phase bridge arm, indicate that bridge arm IGBT is open-minded on corresponding bridge arm when being 1, under Bridge arm IGBT shutdown, 0 indicates its shutdown, and corresponding lower bridge arm is open-minded, u_cFor carrier wave.

Beneficial effect

A kind of square-wave voltage method for implanting based on asymmetric pulse widths modulation proposed by the present invention, when motor is static to estimating It counts d axis and injects square wave voltage signal, ac-dc axis voltage U is exported by PI current regulator_dAnd U_q.And after completing initial alignment The pole N is set to converge to true d axis.After electric motor starting, α β axis high frequency response electric current is obtained by BPF filtering, passes through position detection Unit estimates that rotor-position participates in coordinate transform using the rotor-position of estimation, generates link in pulse and passes through asymmetrical space Vector Modulation mode output voltage pulse.

The position Sensorless Control strategy for realizing permanent magnet synchronous motor location estimation is injected by square-wave voltage, it is contemplated that Rotor position estimate error caused by low switching frequency bring low-order harmonic aggravates, by being used not under analysis low switching frequency Influence with the harmonic wave composition of the high-frequency current signal extracted when pulse modulation method and to rotor position estimate precision, proposes A kind of asymmetric Vector Pulse Width Modulation method, it is intended to realize and reduce high-frequency current signal overlapping, eliminate low order sideband harmonic wave and base Band harmonic wave, improves position estimation accuracy.

The present invention is directed to high frequency response current distortion existing for conventional sinusoidal voltage injection method, carrier wave time under low switching frequency The problems such as harmonic wave frequency multiplication and sideband harmonic wave low order, proposes that one kind realizes square wave electricity based on asymmetric space vector pulse width modulation The method for controlling position-less sensor that pressure injection enters: it selects square-wave voltage as harmonic, exempts location estimation link and largely filter The use of wave device simplifies high frequency signals process；Using asymmetric space vector pulse width modulation (ASVM) method, low order is eliminated Sideband harmonic wave and base-band harmonics reduce the overlapping of high frequency response current signal.The experimental results showed that the square-wave voltage based on ASVM is infused Enter the invalid harmonic components that method is effectively reduced under low switching frequency in high frequency response electric current to interfere, improves rotor-position and estimate Count performance.

1) permanent magnet synchronous motor position Sensorless Control of the present invention, which has the advantage that, selects square-wave voltage to make For harmonic, the use of a large amount of filters of location estimation link is eliminated, improves control system bandwidth；2) using ASVM into Row impulse modulation significantly reduces the sideband harmonic wave and base-band harmonics of high-frequency signal, reduces high-frequency signal overlapping, significantly improves Location estimation effect；3) consider influence of the load current component to position estimation accuracy, extract link in high-frequency signal and pass through BPF filters out load high fdrequency component, further improves location estimation effect.

Detailed description of the invention

Fig. 1: the method for the present invention functional block diagram

Fig. 2: different sample mode comparison diagrams

Fig. 3: traditional SVM modulation principle figure

Fig. 4: ASVM modulation principle figure

Fig. 5: high-frequency current harmonic component composition figure under different modulating mode

Fig. 6: injection square-wave voltage and its high-frequency electrical flow graph of inducting

Fig. 7: high-frequency current envelope line drawing functional block diagram

Fig. 8: normalized and position detection device

Fig. 9: system hardware circuit structure block diagram

Figure 10: asynchronous modulation area output current harmonics component composition figure

Figure 11: position-sensorless control performance of the revolving speed in 200r/min based on traditional SVM modulation under the conditions of semi-load

Figure 12: position-sensorless control performance of the revolving speed in 200r/min based on ASVM modulation under the conditions of semi-load

Specific embodiment

Now in conjunction with embodiment, attached drawing, the invention will be further described:

The control principle block diagram of the method for the present invention is as shown in Figure 1.Wherein, high-frequency current signal i_αβIt is mentioned by bandpass filter It takes, the high-frequency current signal filtered is demodulated by signal and position detection device completes the estimation of revolving speed and position, is given and is handed over Direct-axis currentWith feedback current i_dqDifference by PI current regulator carry out output voltage U_dqCalculating, and by asymmetric Space vector modulation (Asymmetric Space Vector Modulation, ASVM) method controls three-phase full-bridge inverter Output drives permanent magnet synchronous motor, realizes PMSM starting under low switching frequency without position.

Including following several respects:

1, ASVM changes sample mode of the modulating wave in a carrier cycle.Single-phase PWM wave under different sample modes Shape is as shown in Figure 2, wherein ASVM in a carrier cycle 1/4 and 3/4 at take two sampled points, then this is sampled with two Value calculates separately the pulse of first half cycle and later half period, completes two subpulses and updates, sample frequency is switching frequency Twice.When switching frequency is lower, the forward and backward half period sampled point difference of ASVM is larger, closer to Natural Sampling and avoids Complicated operation.Fig. 3, Fig. 4 show modulation principle figure of the seven segmentation SVM and ASVM in a carrier cycle, in figure, The service time of ASVM switching tube is asymmetric in the forward and backward half period.

2, it is electric to system that different impulse modulation modes under low switching frequency are analyzed by fast Fourier analysis method (FFT) Flow the influence that harmonic component generates.Define carrier wave u_CWith modulating wave u_MTime-domain expression are as follows:

Wherein, ω_cFor carrier angular frequencies, ω₀For fundamental wave frequency, θ_cFor carrier phase angle, θ₀For fundamental wave phase angle.Definition carries Wave frequency rate is f_c, fundamental frequency f₀.Based on double Fourier analysis, output voltage f (x, y) is expressed as with x (t) and y (t) The composition of each harmonic component:

F (x, y)=H₁(y)+H₂(x)+H₃(x,y)+H₄(x,y)

Wherein, H₁Indicate DC component, H₂It indicates fundametal compoment and base-band harmonics, frequency is respectively f₀And nf₀(n≠ 1), H₃Indicate carrier harmonics, frequency mfc, H₄Indicate sideband harmonic wave, frequency is mfc ± nf₀, m, n be respectively carrier wave and The integral multiple (m=1,2,3 ..., n=1,2,3 ...) of fundamental frequency.Each harmonic component is expressed as

By taking A phase voltage as an example, harmonic wave of output voltage composition situation is as shown in table 1 under different sample modes.√ is indicated in table This exists, and quantity indicates the intensity of respective component, × indicate to be not present.FFT result display uses asymmetric sample mode The base-band harmonics and sideband harmonic component for making output signal significantly reduce, and Fig. 5 show the high frequency response under different modulating mode Electric current i_αhHarmonic component composition.

Table 1

3, rotor position estimate is realized by Square wave injection, specifically included that

A) after injecting square wave voltage signal to estimation d axis, rotor position is estimated by carrying out signal processing to α β shaft current It sets.The voltage form of injection are as follows:

Wherein, symbol " ∧ " represents the estimated value of corresponding amount, U_hFor the amplitude for injecting square-wave voltage, injected frequency ω_hSetting For the half of switching frequency.The square-wave voltage of injection and its corresponding relationship of the high-frequency current response signal and carrier wave inducted are as schemed Shown in 6.The square wave voltage signal parameter setting injected under experiment condition depends on motor and inverter parameters, at this time switching frequency For 500Hz, square-wave voltage frequency 250Hz, injecting voltage amplitude 10V.

B) high-frequency current response signal is demodulated, carries out envelope line drawing to by the high frequency response electric current of BPF:

Wherein, I_cos、I_sinFor the envelope of high frequency response electric current,θ_rIt is true Real rotor-position,To estimate rotor-position, Δ i_αhWith Δ i_βhFor the high frequency response current differential of two neighboring sampled point.Solution Tune process is as shown in fig. 7, I_cos、I_sinAfter normalized, rotor position error information is demodulated

C) rotor position errorInput as position detection unit as shown in Figure 8 carries out rotor-position and speed Estimation, calculating process are

Wherein,For turn count value, K_p、K_iAnd K_dThe respectively design parameter of position detection unit.