CN103872951A - Permanent magnet synchronous motor torque control method based on sliding mode flux linkage observer - Google Patents

Abstract

The invention discloses a permanent synchronization motor torque control method based on a sliding mode flux linkage observer. Direct torque control is performed on a permanent synchronization motor through a 3/2 coordinate conversion module, the sliding mode flux linkage observer, an electromagnetic torque calculation module, a rotating speed PI adjustor, a torque PI adjustor, a flux linkage self-adaptation module, an expected voltage calculation module, an SVPWM module and an inverter. The sliding mode flux linkage observer is adopted for estimating the size, phase and rotator speed of stator flux linkage, and set torque is processed through the flux linkage self-adaptation module to obtain a set value of the stator flux linkage. Expected voltage calculation is performed on size and phase estimation values and the set value of the stator flux linkage and the output quantity of the torque PI adjustor, so that two-phase alternating-current voltage reference values on a two-phase static coordinate system are obtained, and then through SVPWM conversion, a switching signal is obtained to drive the voltage source inverter to achieve direct torque control over the permanent synchronization motor.

Description

Permagnetic synchronous motor method for controlling torque based on Sliding-Mode Flux Observer of AC

Technical field

The invention belongs to magneto control field, relate in particular to a kind of torsion control system of synchronization generator with everlasting magnetic based on Sliding-Mode Flux Observer of AC.

Background technology

Permagnetic synchronous motor has that volume is little, efficiency is high, is convenient to safeguard and to advantages such as environmental suitability are strong, in many high-grade drives field, be widely used.Direct torque control has that torque response is fast, system configuration is simple and parameter is changed to the advantages such as strong robustness and extremely people's concern.In permagnetic synchronous motor direct torque control, need to obtain stator magnetic linkage, and the whether accurate certainly control performance of fixing system of magnetic linkage signal.Therefore,, for high performance permagnetic synchronous motor Direct Torque Control Speed Regulating System, how accurately to observe stator magnetic linkage particularly important.In traditional direct torque control, generally adopt voltage model or current model to calculate stator magnetic linkage.But in voltage model, owing to being integration to stator winding back-emf, in the time of motor low cruise, stator flux estimation precision degradation, even causes system not work; In current model, need to know rotor-position, increase extra position transducer, this will increase the cost of control system, reduces the reliability of system, also can limit the use occasion of permagnetic synchronous motor simultaneously.In addition, in the direct control of the stagnant chain rate of tradition, also exist the pulsation of torque and magnetic linkage large, the shortcoming such as switching frequency is fixing, and, when motor runs on zero load, introduce reactive current, thereby caused motor power factor to decline.Therefore, for addressing the above problem, be necessary, under the prerequisite of direct-axis current in the time improving switching frequency and reduce zero load, to propose a kind of new Flux Observation Method, to improve dynamic and static state performance, reliability, robustness and the antijamming capability of Direct Torque Control System for Permanent Magnet Synchronous Motor.

Summary of the invention

Technical problem: the deficiency existing for above-mentioned prior art, a kind of permagnetic synchronous motor method for controlling torque based on Sliding-Mode Flux Observer of AC is provided, in the time improving switching frequency and reduce zero load, under the prerequisite of direct-axis current, improve permagnetic synchronous motor direct torque control robustness and antijamming capability.

Technical scheme: the permagnetic synchronous motor method for controlling torque based on Sliding-Mode Flux Observer of AC, by 3/2 coordinate transformation module, Sliding-Mode Flux Observer of AC, electromagnetic torque computing module, rotating speed pi regulator, PI torque controller, magnetic linkage adaptation module, expection voltage computing module, SVPWM module and inverter, permagnetic synchronous motor is carried out to direct torque control, comprises following concrete steps:

Step 1), the three-phase current i of detection permagnetic synchronous motor _a, i _b, i _cwith three-phase voltage u _a, u _b, u _c, after 3/2 coordinate transform, obtain the current component i under the static interchange coordinate of two-phase _α, i _βwith component of voltage u _α, u _β, then by described current component i _α, i _βwith component of voltage u _α, u _βdeliver to Sliding-Mode Flux Observer of AC, and by current component i _α, i _βdeliver to electromagnetic torque computing module;

Step 2), according to described current component i _α, i _βwith component of voltage u _α, u _β, described Sliding-Mode Flux Observer of AC module estimation stator magnetic linkage magnitude estimation value

with stator magnetic linkage phase estimation value

and spinner velocity estimated value

Step 3), by given rotating speed ω ^*with described spinner velocity estimated value

do, after difference, after rotating speed pi regulator, to obtain given torque Te ^*;

Step 4), according to described stator magnetic linkage magnitude estimation value

and described current component i _α, i _β, described electromagnetic torque computing module obtains actual motor torque Te;

Step 5), described given torque Te ^*obtain stator flux linkage set value ψ through magnetic linkage adaptation module _sref;

Step 6), by described given torque Te ^*do, after difference, after PI torque controller, to obtain output variable Δ δ with described actual motor torque Te;

Step 7), described output variable Δ δ, stator flux linkage set value ψ _s.ref, stator magnetic linkage magnitude estimation value

and stator magnetic linkage phase estimation value through expection voltage computing module, obtain the two-phase alternating current pressure reference value that two-phase static coordinate is fastened

Step 8), press reference value according to stator magnetic linkage vector position and described two-phase alternating current

from on off state table, select after corresponding space voltage vector, to inverter, realize the direct torque control of permagnetic synchronous motor through described SVPWM module output modulation signal by described inverter.

As preferred version of the present invention, described step 2) comprise following concrete steps:

Step 2.1), according to described current component i _α, i _βwith component of voltage u _α, u _β, structure sliding mode observer obtains the back electromotive force e of motor _α, e _β;

Step 2.2), according to described back electromotive force e _α, e _β, obtain rotor estimated position by rotor-position computing module

Step 2.3), according to described rotor estimated position

obtain current stator magnetic linkage vector ψ by stator flux estimation module _α, ψ _β;

Step 2.4), according to described current stator magnetic linkage vector ψ _α, ψ _β, obtain stator magnetic linkage magnitude estimation value by flux observer

and spinner velocity estimated value

Step 2.5), according to described stator magnetic linkage magnitude estimation value

obtain stator magnetic linkage phase estimation value by magnetic linkage position computation module

As improvement of the present invention, step 2.1) described in the change structure function of sliding mode observer be sigmoid function.

Beneficial effect: the present invention uses sliding mode control algorithm estimation stator magnetic linkage and rotor-position, can accurately control in real time stator magnetic linkage, and realize the permagnetic synchronous motor direct torque control based on position Sensorless Control, has following beneficial effect:

(1) this method is in conjunction with SVPWM technology and magnetic linkage adaptive method, therefore can reduce torque and magnetic linkage pulsation in direct torque control, greatly improve switching frequency, to improve current waveform, also direct-axis current component simultaneously while having reduced empty load of motor or shock load, thereby can reduce the loss of electric machine, improve electric efficiency;

(2) structure Sliding-Mode Flux Observer of AC estimation stator magnetic linkage and spinner velocity, the estimation precision of stator magnetic linkage while having improved low speed, thereby improve system low-speed performance, saved position transducer simultaneously, thereby reduce the cost of control system, improve the reliability of system, simplified system configuration;

(3) this method applies to magnetic linkage adaptive method, Sliding-Mode Flux Observer of AC and SVPWM triplicity in Direct Torque Control System for Permanent Magnet Synchronous Motor first, make control system not only retain good dynamic and static state performance, antijamming capability and the robustness in sliding formwork control, also widened the range of operation of system;

(4) method therefor amount of calculation is little, is easy to realize, and is conducive to the through engineering approaches of new theory and practical.

Brief description of the drawings

Fig. 1 is the structured flowchart that the present invention is based on the torsion control system of synchronization generator with everlasting magnetic of Sliding-Mode Flux Observer of AC;

Fig. 2 is Sliding-Mode Flux Observer of AC theory structure block diagram.

Embodiment

Below in conjunction with Fig. 1, Fig. 2, technical scheme of the present invention is described in further detail.

As shown in Figure 1, the torsion control system of synchronization generator with everlasting magnetic that the present invention is based on Sliding-Mode Flux Observer of AC comprises that permagnetic synchronous motor, 3/2 coordinate transform, Sliding-Mode Flux Observer of AC, electromagnetic torque calculating, rotating speed pi regulator, PI torque controller, magnetic linkage self adaptation, expection voltage calculate, SVPWM module and inverter.

The concrete implementation step of permagnetic synchronous motor method for controlling torque that the present invention is based on Sliding-Mode Flux Observer of AC is as follows:

Step 1), the three-phase current i of detection permagnetic synchronous motor _a, i _b, i _cwith three-phase voltage u _a, u _b, u _c, after 3/2 coordinate transform, obtain the current component i under the static interchange coordinate of two-phase _α, i _βwith component of voltage u _α, u _β, then by current component i _α, i _βwith component of voltage u _α, u _βdeliver to Sliding-Mode Flux Observer of AC, and by current component i _α, i _βdeliver to electromagnetic torque computing module;

Step 2), according to current component i _α, i _βwith component of voltage u _α, u _β, use Sliding-Mode Flux Observer of AC module estimation stator magnetic linkage magnitude estimation value

with stator magnetic linkage phase estimation value

and spinner velocity estimated value

as shown in Figure 2, specific algorithm is as follows for its theory diagram:

Step 2.1), according to current component i _α, i _βwith component of voltage u _α, u _β, structure sliding mode observer obtains the back electromotive force e of motor _α, e _β; Wherein, structure sliding formwork current observer, specific as follows:

Permagnetic synchronous motor Mathematical Modeling is expressed as under α β coordinate system:

$\left\{\begin{array}{c}{L}_s\frac{{\mathrm{di}}_{\mathrm{\α}}}{\mathrm{dt}}=-R_s{i}_{\mathrm{\α}}-e_{\mathrm{\α}}+u_{\mathrm{\α}}\\ L_s\frac{{\mathrm{di}}_{\mathrm{\β}}}{\mathrm{dt}}=-R_s{i}_{\mathrm{\β}}-e_{\mathrm{\β}}+u_{\mathrm{\β}}\\ e_{\mathrm{\α}}=-{\mathrm{\ψ}}_f\mathrm{\ω}\sin \mathrm{\θ}\\ e_{\mathrm{\β}}={\mathrm{\ψ}}_f\mathrm{\ω}\cos \mathrm{\θ}\end{array}\right.---\left(1\right)$

Wherein, L _sfor the synchronous inductance of motor; ψ _ffor permanent magnetism magnetic linkage; ω is rotor electric angle speed; R _sfor stator resistance; e _αand e _βfor α, the beta-axis component of winding back emf;

According to sliding mode control theory, in the time that system is slided on sliding-mode surface, have:

$S\left(X\right)={\hat{i}}_s-i_s=0---\left(2\right)$

Wherein,

for electric current estimated value; i _s=[i _αi _β] ^tfor current actual value;

For reducing system chatter, employing sigmoid function replaces the switch function of traditional sliding moding structure, as sliding moding structure function:

$\left\{\begin{array}{c}{L}_s\left(\frac{d{\hat{i}}_{\mathrm{\α}}}{\mathrm{dt}}\right)=-R_s{\hat{i}}_{\mathrm{\α}}+u_{\mathrm{\α}}-\mathrm{kH}({\hat{i}}_{\mathrm{\α}}-i_{\mathrm{\α}})\\ L_s\left(\frac{d{\hat{i}}_{\mathrm{\β}}}{\mathrm{dt}}\right)=-R_s{\hat{i}}_{\mathrm{\β}}+u_{\mathrm{\β}}-\mathrm{kH}({\hat{i}}_{\mathrm{\β}}-i_{\mathrm{\β}})\end{array}\right.---\left(3\right)$

Wherein, k is sliding formwork coefficient; H is sigmoid function;

with

for α, the beta-axis component of estimation stator current;

It is as follows that definition becomes structure function:

$H\left(x\right)=\mathrm{sigmoid}\left(S\right)=\left[\frac{2}{1+e^{-\mathrm{ax}}}\right]-1---\left(4\right)$

Wherein, S is the difference of estimation electric current and actual current; A is greater than zero real number, can regulate according to actual conditions;

Formula (3) and formula (1) are subtracted each other, can obtain the dynamical equation of sliding mode observer:

$\left\{\begin{array}{c}{L}_s\left(\frac{{\mathrm{dS}}_{\mathrm{\α}}}{\mathrm{dt}}\right)=-R_s{S}_{\mathrm{\α}}\left(X\right)+e_{\mathrm{\α}}-\mathrm{kH}({\hat{i}}_{\mathrm{\α}}-i_{\mathrm{\α}})\\ L_s\left(\frac{{\mathrm{dS}}_{\mathrm{\β}}}{\mathrm{dt}}\right)=-R_s{S}_{\mathrm{\β}}\left(X\right)+e_{\mathrm{\β}}-\mathrm{kH}({\hat{i}}_{\mathrm{\β}}-i_{\mathrm{\β}})\end{array}\right.---\left(5\right)$

Wherein, S _αand S (X) _β(X) be α, the beta-axis component of the difference of estimation electric current and actual current;

According to existence and the stability condition of sliding formwork motion, the prerequisite that the rotor-position of motor can be estimated is smoothly to meet:

$\begin{array}{c}\stackrel{\·}{V}=S{\left(X\right)}^T\stackrel{\·}{S}\left(X\right)=S_{\mathrm{\α}}{\stackrel{\·}{S}}_{\mathrm{\α}}+S_{\mathrm{\β}}{\stackrel{\·}{S}}_{\mathrm{\β}}=\frac{1}{L_s}[({\hat{i}}_{\mathrm{\α}}-i_{\mathrm{\α}})e_{\mathrm{\α}}-k({\hat{i}}_{\mathrm{\α}}-i_{\mathrm{\α}})H({\hat{i}}_{\mathrm{\α}}-i_{\mathrm{\α}})]\\ +\frac{1}{L_s}[({\hat{i}}_{\mathrm{\β}}-i_{\mathrm{\β}})e_{\mathrm{\β}}-k({\hat{i}}_{\mathrm{\β}}-i_{\mathrm{\β}})H({\hat{i}}_{\mathrm{\β}}-i_{\mathrm{\β}})]-\frac{R_s}{L_s}[{({\hat{i}}_{\mathrm{\α}}-i_{\mathrm{\α}})}^2+{({\hat{i}}_{\mathrm{\β}}-i_{\mathrm{\β}})}^2]\≤0\end{array}$

:

k＞max(|e _α|，|e _β|) (6)

Therefore, k takes fully enough large, can ensure the asymptotic stability of sliding formwork motion, in the time that system reaches sliding-mode surface, has:

$\stackrel{\·}{S}\left(X\right)=S\left(X\right)=0---\left(7\right)$

Above formula substitution formula (5) can be obtained to the back electromotive force e of motor _α, e _β:

$\left\{\begin{array}{c}{e}_{\mathrm{\α}}=\mathrm{kH}({\hat{i}}_{\mathrm{\α}}-i_{\mathrm{\α}})\\ e_{\mathrm{\β}}=\mathrm{kH}({\hat{i}}_{\mathrm{\β}}-i_{\mathrm{\β}})\end{array}\right.---\left(8\right)$

Step 2.2), according to back electromotive force e _α, e _β, obtain the rotor estimated position of motor by rotor-position computing module

for:

$\widehat{\mathrm{\θ}}=-{\tan }^{-1}\left(\frac{e_{\mathrm{\α}}}{e_{\mathrm{\β}}}\right)---\left(9\right)$

Step 2.3), according to rotor estimated position

and in conjunction with current component i under two-phase rest frame _αand i _β, obtain current stator magnetic linkage vector ψ by stator flux estimation module primary Calculation _α, ψ _β:

$\left\{\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{\α}}=L_s{i}_{\mathrm{\α}}+{\mathrm{\ψ}}_f\cos \widehat{\mathrm{\θ}}\\ {\mathrm{\ψ}}_{\mathrm{\β}}=L_s{i}_{\mathrm{\β}}+{\mathrm{\ψ}}_f\sin \widehat{\mathrm{\θ}}\end{array}\right.---\left(10\right)$

Due to step 2.1) in contain high fdrequency component in the sliding formwork current observer of constructing, therefore the stator magnetic linkage estimating also contains high fdrequency component, need to adopt low pass filter to carry out filtering, but the use of low pass filter can bring phase delay, affect the precision of magnetic linkage estimation, for improving the estimation precision of magnetic linkage, the present invention has constructed a kind of novel flux observer;

Step 2.4), according to current stator magnetic linkage vector ψ _α, ψ _β, obtain stator magnetic linkage magnitude estimation value by flux observer

and spinner velocity estimated value

concrete steps are as follows:

Structure flux observer, to improve the estimation precision of magnetic linkage, and uses the stability of Lyapunov quantitative analysis flux observer, specific as follows:

To formula (10) differentiate, can obtain:

$\left\{\begin{array}{c}\frac{{\mathrm{d\ψ}}_{\mathrm{\α}}}{\mathrm{dt}}=L_s\frac{{\mathrm{di}}_{\mathrm{\α}}}{\mathrm{dt}}-\mathrm{\ω}{\mathrm{\ψ}}_{\mathrm{\β}}+{\mathrm{\ωL}}_s{i}_{\mathrm{\β}}\\ \frac{{\mathrm{d\ψ}}_{\mathrm{\β}}}{\mathrm{dt}}=L_s\frac{{\mathrm{di}}_{\mathrm{\β}}}{\mathrm{dt}}+\mathrm{\ω}{\mathrm{\ψ}}_{\mathrm{\α}}-{\mathrm{\ωL}}_s{i}_{\mathrm{\α}}\end{array}\right.---\left(11\right)$

Wherein, ω is rotor electric angle speed;

According to above formula, can construct flux observer:

$\left\{\begin{array}{c}\frac{d{\widehat{\mathrm{\ψ}}}_{\mathrm{\α}}}{\mathrm{dt}}=L_s\frac{d{\hat{i}}_{\mathrm{\α}}}{\mathrm{dt}}-\widehat{\mathrm{\ω}}{\widehat{\mathrm{\ψ}}}_{\mathrm{\β}}+\widehat{\mathrm{\ω}}{L}_s{\hat{i}}_{\mathrm{\α}}-k({\hat{i}}_{\mathrm{\α}}-i_{\mathrm{\α}})-l({\widehat{\mathrm{\ψ}}}_{\mathrm{\α}}-{\mathrm{\ψ}}_{\mathrm{\α}})\\ \frac{d{\widehat{\mathrm{\ψ}}}_{\mathrm{\β}}}{\mathrm{dt}}=L_s\frac{d{\hat{i}}_{\mathrm{\β}}}{\mathrm{dt}}+\widehat{\mathrm{\ω}}{\widehat{\mathrm{\ψ}}}_{\mathrm{\α}}-\widehat{\mathrm{\ω}}{L}_s{\hat{i}}_{\mathrm{\β}}-k({\hat{i}}_{\mathrm{\β}}-i_{\mathrm{\β}})-l({\widehat{\mathrm{\ψ}}}_{\mathrm{\β}}-{\mathrm{\ψ}}_{\mathrm{\β}})\\ \frac{d\widehat{\mathrm{\ω}}}{\mathrm{dt}}=({\hat{i}}_{\mathrm{\α}}-i_{\mathrm{\α}}){\hat{i}}_{\mathrm{\β}}-({\hat{i}}_{\mathrm{\β}}-i_{\mathrm{\β}}){\hat{i}}_{\mathrm{\α}}+({\widehat{\mathrm{\ψ}}}_{\mathrm{\α}}-{\mathrm{\ψ}}_{\mathrm{\α}}){\widehat{\mathrm{\ψ}}}_{\mathrm{\β}}-({\widehat{\mathrm{\ψ}}}_{\mathrm{\β}}-{\mathrm{\ψ}}_{\mathrm{\β}}){\widehat{\mathrm{\ψ}}}_{\mathrm{\α}}\end{array}\right.---\left(12\right)$

Wherein, l is flux observer gain, and its value is greater than zero;

for the component of estimation magnetic linkage in α β coordinate system;

for rotor estimation electric angle speed;

By in formula (7) substitution formula (12), can obtain:

$\left\{\begin{array}{c}\frac{d{\widehat{\mathrm{\ψ}}}_{\mathrm{\α}}}{\mathrm{dt}}=L_s\frac{d{\hat{i}}_{\mathrm{\α}}}{\mathrm{dt}}-{\widehat{\mathrm{\ω}}\widehat{\mathrm{\ψ}}}_{\mathrm{\β}}+\widehat{\mathrm{\ω}}{L}_s{\hat{i}}_{\mathrm{\α}}-l({\widehat{\mathrm{\ψ}}}_{\mathrm{\α}}-{\mathrm{\ψ}}_{\mathrm{\α}})\\ \frac{d{\widehat{\mathrm{\ψ}}}_{\mathrm{\β}}}{\mathrm{dt}}=L_s\frac{d{\hat{i}}_{\mathrm{\β}}}{\mathrm{dt}}+\widehat{\mathrm{\ω}}{\widehat{\mathrm{\ψ}}}_{\mathrm{\α}}-\widehat{\mathrm{\ω}}{L}_s{\hat{i}}_{\mathrm{\β}}-l({\widehat{\mathrm{\ψ}}}_{\mathrm{\β}}-{\mathrm{\ψ}}_{\mathrm{\β}})\\ \frac{d\widehat{\mathrm{\ω}}}{\mathrm{dt}}=({\widehat{\mathrm{\ψ}}}_{\mathrm{\α}}-{\mathrm{\ψ}}_{\mathrm{\α}}){\widehat{\mathrm{\ψ}}}_{\mathrm{\β}}-({\widehat{\mathrm{\ψ}}}_{\mathrm{\β}}-{\mathrm{\ψ}}_{\mathrm{\β}}){\widehat{\mathrm{\ψ}}}_{\mathrm{\α}}\end{array}\right.---\left(13\right)$

By poor to formula (13) and formula (11), the error equation that obtains flux observer is:

$\left\{\begin{array}{c}\frac{d{\widetilde{\mathrm{\ψ}}}_{\mathrm{\α}}}{\mathrm{dt}}=-\widetilde{\mathrm{\ω}}{\widehat{\mathrm{\ψ}}}_{\mathrm{\β}}+\widehat{\mathrm{\ω}}{\widetilde{\mathrm{\ψ}}}_{\mathrm{\β}}-l{\widetilde{\mathrm{\ψ}}}_{\mathrm{\α}}\\ \frac{d{\widetilde{\mathrm{\ψ}}}_{\mathrm{\β}}}{\mathrm{dt}}=-\widetilde{\mathrm{\ω}}{\widehat{\mathrm{\ψ}}}_{\mathrm{\α}}+\widehat{\mathrm{\ω}}{\widetilde{\mathrm{\ψ}}}_{\mathrm{\α}}-l{\widetilde{\mathrm{\ψ}}}_{\mathrm{\β}}\\ \frac{d\widehat{\mathrm{\ω}}}{\mathrm{dt}}={\widetilde{\mathrm{\ψ}}}_{\mathrm{\α}}{\widehat{\mathrm{\ψ}}}_{\mathrm{\β}}{-\widetilde{\mathrm{\ψ}}}_{\mathrm{\β}}{\widehat{\mathrm{\ψ}}}_{\mathrm{\α}}\end{array}\right.---\left(14\right)$

Wherein, ω is rotor electric angle speed; L is flux observer gain, and its value is greater than zero;

for the component of estimation magnetic linkage in α β coordinate system;

for rotor estimation electric angle speed;

${\widetilde{\mathrm{\ψ}}}_{\mathrm{\β}}={\widehat{\mathrm{\ψ}}}_{\mathrm{\β}}-{\mathrm{\ψ}}_{\mathrm{\β}},\widetilde{\mathrm{\ω}}=\widehat{\mathrm{\ω}}-\mathrm{\ω};$

The stability of utilizing Lyapunov theorem proving flux observer, has:

$V=\frac{1}{2}({{\widetilde{\mathrm{\ψ}}}_{\mathrm{\α}}}^2+{{\widetilde{\mathrm{\ψ}}}_{\mathrm{\β}}}^2+{\widetilde{\mathrm{\ω}}}^2)---\left(15\right)$

To formula (15), differentiate has:

$\stackrel{\·}{V}={\widetilde{\mathrm{\ψ}}}_{\mathrm{\α}}{\stackrel{\·}{\widetilde{\mathrm{\ψ}}}}_{\mathrm{\α}}+{\widetilde{\mathrm{\ψ}}}_{\mathrm{\β}}{\stackrel{\·}{\widetilde{\mathrm{\ψ}}}}_{\mathrm{\β}}+\widetilde{\mathrm{\ω}}\stackrel{\·}{\widetilde{\mathrm{\ω}}}---\left(16\right)$

Formula (14) substitution formula (16) is arranged and can be obtained:

$\stackrel{\·}{V}=-l_1({{\widetilde{\mathrm{\ψ}}}_{\mathrm{\α}}}^2+{{\widetilde{\mathrm{\ψ}}}_{\mathrm{\β}}}^2)\≤0---\left(17\right)$

Can be found out by formula (17), this flux observer is asymptotically stable, therefore, can calculate stator flux estimation value according to formula (14)

with turn count value

Step 2.5), according to stator magnetic linkage magnitude estimation value

obtain stator magnetic linkage phase estimation value by magnetic linkage position computation module

${\widehat{\mathrm{\θ}}}_S=\arctan ({\widehat{\mathrm{\ψ}}}_{\mathrm{\α}}/{\widehat{\mathrm{\ψ}}}_{\mathrm{\β}})---\left(18\right)$

Step 3), by given rotating speed ω ^*with spinner velocity estimated value

do, after difference, after rotating speed pi regulator, to obtain given torque Te ^*;

Step 4), according to stator magnetic linkage magnitude estimation value

and current component i under two-phase static coordinate _α, i _β, obtain actual motor torque Te through electromagnetic torque computing module, specific as follows:

$T_e=\frac{3}{2}{p}_0({\widehat{\mathrm{\ψ}}}_{\mathrm{\α}}{\hat{i}}_{\mathrm{\β}}-{\widehat{\mathrm{\ψ}}}_{\mathrm{\β}}{\hat{i}}_{\mathrm{\α}})---\left(19\right)$

Wherein, p ₀for the number of pole-pairs of motor;

Step 5), given torque Te ^*obtain stator flux linkage set value ψ through magnetic linkage adaptation module _s.ref, specific as follows:

Permanent-magnetic synchronous motor stator magnetic linkage ac-dc axis component ψ _sq, ψ _sdfor:

$\left\{\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{sd}}=L_d{i}_d+{\mathrm{\ψ}}_f\\ {\mathrm{\ψ}}_{\mathrm{sq}}=L_q{i}_q\end{array}\right.---\left(20\right)$

Wherein, L _dand L _qfor the dq axle component of stator inductance, i _dand i _qfor the dq axle component of stator current;

Relation between motor torque and stator magnetic linkage component is as follows:

$T_e=\frac{3}{2}{p}_0{\mathrm{\ψ}}_f{\mathrm{\ψ}}_s\sin \mathrm{\δ}=\frac{3}{2}{p}_0\frac{1}{L_S}{\mathrm{\ψ}}_f{\mathrm{\ψ}}_{\mathrm{sq}}---\left(21\right)$

Wherein, ψ _sfor stator magnetic linkage, δ is power angle;

In formula (20), make i _d=0, then convolution (21), can obtain the reference value ψ of stator flux linkage set _sreffor:

$\left\{\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{sd}}^{*}={\mathrm{\ψ}}_f\\ {\mathrm{\ψ}}_{\mathrm{sq}}^{*}=\frac{2T_e^{*}{L}_s}{3p_0{\mathrm{\ψ}}_f}\\ {\mathrm{\ψ}}_{\mathrm{sref}}=\sqrt{{{\mathrm{\ψ}}_{\mathrm{sd}}^{*}}^2+{{\mathrm{\ψ}}_{\mathrm{sq}}^{*}}^2}\end{array}\right.---\left(22\right)$

Step 6), by given torque Te ^*do, after difference, after PI torque controller, to obtain output variable Δ δ with described actual motor torque Te;

Step 7), output variable Δ δ, stator flux linkage set value ψ _s.ref, stator magnetic linkage magnitude estimation value

and stator magnetic linkage phase estimation value

through expection voltage computing module, obtain the two-phase alternating current pressure reference value that two-phase static coordinate is fastened

Step 8), press reference value according to stator magnetic linkage vector position and described two-phase alternating current

from on off state table, select after corresponding space voltage vector, to inverter, realize the direct torque control of permagnetic synchronous motor through SVPWM module output modulation signal by inverter.

In the present invention, the estimation of stator magnetic linkage vector and spinner velocity adopt Sliding-Mode Flux Observer of AC, not only have the advantages such as sliding Mode Algorithm is simple, strong robustness, and, with respect to traditional voltage model, when low speed, the estimation precision of stator magnetic linkage improves greatly, has improved motor low cruise performance; With respect to traditional current model, without extra position transducer, control system cost, the reliability of system improves; Obtain stator flux linkage set value by magnetic linkage adaptive method, its value changes according to the size of load, therefore, has reduced direct-axis current when motor runs on zero load or impact heavy duty, has improved electric efficiency.Energy real-time monitored of the present invention is with control stator magnetic linkage and in conjunction with magnetic linkage adaptive method and SVPWM technology, can effectively reduce torque and magnetic linkage pulsation, improve switching frequency and electric efficiency, widen the range of operation of system, meanwhile, also there is good dynamic and static state performance, reliability, robustness and antijamming capability.

The above is only the preferred embodiment of the present invention; it should be pointed out that for those skilled in the art, under the premise without departing from the principles of the invention; can also make some improvements and modifications, these improvements and modifications also should be considered as protection scope of the present invention.

Claims (3)

1. the permagnetic synchronous motor method for controlling torque based on Sliding-Mode Flux Observer of AC, it is characterized in that: by 3/2 coordinate transformation module, Sliding-Mode Flux Observer of AC, electromagnetic torque computing module, rotating speed pi regulator, PI torque controller, magnetic linkage adaptation module, expection voltage computing module, SVPWM module and inverter, permagnetic synchronous motor is carried out to direct torque control, comprise following concrete steps:

Step 1), the three-phase current i of detection permagnetic synchronous motor _a, i _b, i _cwith three-phase voltage u _a, u _b, u _c, after 3/2 coordinate transform, obtain the current component i under the static interchange coordinate of two-phase _α, i _βwith component of voltage u _a, u _β, then by described current component i _α, i _βwith component of voltage u _α, u _βdeliver to Sliding-Mode Flux Observer of AC, and by current component i _α, i _βdeliver to electromagnetic torque computing module;

Step 2), according to described current component i _α, i _βwith component of voltage u _α, u _β, described Sliding-Mode Flux Observer of AC module estimation stator magnetic linkage magnitude estimation value

with stator magnetic linkage phase estimation value

and spinner velocity estimated value

Step 3), by given rotating speed ω ^*with described spinner velocity estimated value

do, after difference, after rotating speed pi regulator, to obtain given torque Te ^*;

Step 4), according to described stator magnetic linkage magnitude estimation value

and described current component i _α, i _β, described electromagnetic torque computing module obtains actual motor torque Te;

Step 5), described given torque Te ^*obtain stator flux linkage set value ψ through magnetic linkage adaptation module _sref;

Step 6), by described given torque Te ^*do, after difference, after PI torque controller, to obtain output variable Δ δ with described actual motor torque Te;

Step 7), described output variable Δ δ, stator flux linkage set value ψ _s.ref, stator magnetic linkage magnitude estimation value and stator magnetic linkage phase estimation value

through expection voltage computing module, obtain the two-phase alternating current pressure reference value that two-phase static coordinate is fastened

Step 8), press reference value according to stator magnetic linkage vector position and described two-phase alternating current

from on off state table, select after corresponding space voltage vector, to inverter, realize the direct torque control of permagnetic synchronous motor through described SVPWM module output modulation signal by described inverter.

2. the permagnetic synchronous motor method for controlling torque based on Sliding-Mode Flux Observer of AC according to claim 1, is characterized in that: described step 2) comprise following concrete steps:

Step 2.1), according to described current component i _α, i _βwith component of voltage u _α, u _β, structure sliding mode observer obtains the back electromotive force e of motor _α, e _β;

Step 2.2), according to described back electromotive force e _α, e _β, obtain rotor estimated position by rotor-position computing module

Step 2.3), according to described rotor estimated position

obtain current stator magnetic linkage vector ψ by stator flux estimation module _α, ψ _β;

Step 2.4), according to described current stator magnetic linkage vector ψ _α, ψ _β, obtain stator magnetic linkage magnitude estimation value by flux observer

and spinner velocity estimated value

Step 2.5), according to described stator magnetic linkage magnitude estimation value

obtain stator magnetic linkage phase estimation value by magnetic linkage position computation module

3. the permagnetic synchronous motor method for controlling torque based on Sliding-Mode Flux Observer of AC according to claim 2, is characterized in that: step 2.1) described in the change structure function of sliding mode observer be sigmoid function.

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