CN103647491A - Stator field orientation vector control device and angle compensation method thereof - Google Patents

Abstract

The invention relates to a stator field orientation vector control device and an angle compensation method thereof. An angle compensation step is added in magnetic flow observation; and after compensation, the branch quantities of stator flux linkage in Alpha and beta axis are displayed in the specification. Therefore, the problem that stator magnetic flux phase cannot be obtained accurately during digital realization is solved, and accuracy of stator field orientation is guaranteed, and precision and dynamic-state and steady-state performances of stator field orientation vector control are greatly improved.

Description

Stator flux orientation vector control apparatus and angle compensation process thereof

Technical field

The invention belongs to motor-driven technical field, relate to a kind of stator flux orientation vector control apparatus and angle compensation process thereof.

Background technology

The sensitiveness to the parameter of electric machine is smaller is more and more applied due to it for asynchronous machine stator flux orientation vector control technology.This vector control technology is decomposed into exciting current and torque current by rotating coordinate transformation by stator current, and then realizes the decoupling zero control of magnetic flux and torque.Flux observer is the core of this control technology, and the accuracy of stator magnetic flux angle has directly determined the dynamic and steady-state behaviour of motor.The existing flux observer based on voltage model as shown in Figure 1.In the Digital Implementation of stator flux orientation vector control, rotation of coordinate angle used is all to calculate gained angle a upper interrupt cycle, because stator field rotates with synchronous speed, therefore can there is an error △ θ in angle and the current angle in a upper cycle, and then cause the inaccurate of stator flux orientation, as shown in Figure 2.

Rising along with rotating speed, △ θ will constantly increase, cause stator voltage to increase at the component of d axle, the component of q axle reduces, under identical magnetic flux amplitude, the electric current of q axle also can reduce a lot, even can not trace command, had a strong impact on the output of motor torque, therefore need to compensate angular error △ θ.

Summary of the invention

The object of this invention is to provide a kind of stator flux orientation vector control apparatus and angle compensation process thereof, to realize the accurate observation of stator magnetic flux angle, improve the dynamic and steady-state behaviour of stator flux orientation vector control.

For achieving the above object, stator flux orientation vector control apparatus of the present invention comprises magnetic flux observation module, and described magnetic flux observation module comprises angle compensation unit, and after compensation, stator magnetic linkage at the component of α, β axle is $\left\{\begin{array}{c}{{\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}}^{\′}={\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}\cos \left(\mathrm{\Δ\θ}\right)-{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}\sin \left(\mathrm{\Δ\θ}\right)\\ {{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}}^{\′}={\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}\sin \left(\mathrm{\Δ\θ}\right)+{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}\cos \left(\mathrm{\Δ\θ}\right)\end{array}\right.;$

In formula, △ θ is angular error amount,

represent respectively stator magnetic linkage after compensation at the component of α, β axle and the stator magnetic linkage before compensation the component at α, β axle.

The angle compensation process of stator flux orientation vector control apparatus of the present invention, includes magnetic flux observation procedure, increases angle compensation link in described magnetic flux observation procedure: after compensation, stator magnetic linkage at the component of α, β axle is $\left\{\begin{array}{c}{{\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}}^{\′}={\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}\cos \left(\mathrm{\Δ\θ}\right)-{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}\sin \left(\mathrm{\Δ\θ}\right)\\ {{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}}^{\′}={\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}\sin \left(\mathrm{\Δ\θ}\right)+{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}\cos \left(\mathrm{\Δ\θ}\right)\end{array}\right.;$ In formula, △ θ is angular error amount,

represent respectively stator magnetic linkage after compensation at the component of α, β axle and the stator magnetic linkage before compensation the component at α, β axle.

Described angular error calculates by the switching frequency of frequency converter and the rotating speed of motor actual motion

wherein n is motor speed, n _pfor motor number of pole-pairs, f _sswitching frequency for frequency converter.

Stator flux orientation vector control apparatus of the present invention and angle compensation process thereof, angle to magnetic flux observation compensates, the problem that while having solved Digital Implementation, stator magnetic flux phase place can not accurately obtain, guarantee the accuracy of stator flux orientation, greatly improved precision and its dynamic, the steady-state behaviour of stator flux orientation vector control.

Accompanying drawing explanation

Fig. 1 is existing flux observer control block diagram;

Fig. 2 is that stator flux orientation is controlled polar plot;

Fig. 3 is the control block diagram of flux observer embodiment of the present invention.

Embodiment

Stator flux orientation vector control apparatus of the present invention and angle compensation process are the improvement that the flux observer of existing stator flux orientation vector control is carried out, at flux observer, increase angle compensation unit, in magnetic flux observation procedure, increase angle compensation link, stator magnetic linkage under α β coordinate system is compensated by angle compensation unit, obtain the component of current time stator magnetic linkage under α β coordinate system.

The amplitude of stator magnetic linkage can think and remain unchanged in former and later two interrupt cycles, and before can being compensated according to Fig. 2, the component of stator magnetic linkage under α β coordinate system is

$\left\{\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{s\α}}={\mathrm{\ψ}}_s\cos \left(\mathrm{\θ}\right)\\ {\mathrm{\ψ}}_{\mathrm{s\β}}={\mathrm{\ψ}}_s\sin \left(\mathrm{\θ}\right)\end{array}\right.---\left(1\right)$

The component of actual stator magnetic linkage under α β coordinate system is

$\left\{\begin{array}{c}{{\mathrm{\ψ}}_{\mathrm{s\α}}}^{\′}={\mathrm{\ψ}}_s\cos (\mathrm{\θ}+\mathrm{\Δ\θ})\\ {{\mathrm{\ψ}}_{\mathrm{s\β}}}^{\′}={\mathrm{\ψ}}_s\sin (\mathrm{\θ}+\mathrm{\Δ\θ})\end{array}\right.---\left(2\right)$

ψ wherein _sfor stator magnetic linkage amplitude, θ is the phase place of last interrupt cycle of stator magnetic linkage, ψ _{s α}for last interrupt cycle stator magnetic linkage at the component of α axle, ψ _{s β}for last interrupt cycle stator magnetic linkage at the component of β axle, △ θ is angular error, ψ _{s α}' be that current time stator magnetic linkage is at the component of α axle, ψ _{s β}' be that current time stator magnetic linkage is at the component of β axle.

According to formula (1) and (2), can draw, in flux observer, the measured value after the measured value of stator magnetic linkage before α β coordinate system compensation and compensation meets formula (3).

$\left\{\begin{array}{c}{{\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}}^{\′}={\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}\cos \left(\mathrm{\Δ\θ}\right)-{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}\sin \left(\mathrm{\Δ\θ}\right)\\ {{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}}^{\′}={\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}\sin \left(\mathrm{\Δ\θ}\right)+{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}\cos \left(\mathrm{\Δ\θ}\right)\end{array}\right.---\left(3\right)$

In formula, △ θ is angular error amount,

represent respectively stator magnetic linkage after compensation at the component of α, β axle and the stator magnetic linkage before compensation the component at α, β axle.

Stator flux device be take the existing stator flux device based on voltage model as basis, and specific implementation process comprises four aspects, and the first, compensation front stator magnetic linkage is in the calculating of α, beta-axis component; The second, the calculating of stator magnetic flux offset angle tolerance; The 3rd, according to compensation front stator magnetic linkage, in α, beta-axis component and stator magnetic flux offset angle tolerance, calculate the rear stator magnetic linkage of compensation in the calculating of α, beta-axis component; The 4th, according to stator magnetic linkage after compensation, at α, beta-axis component, calculate amplitude and the phase place of stator magnetic flux.Stator flux device after improvement as shown in Figure 3.

1) compensation front stator magnetic linkage is in the calculating of α, beta-axis component

Compensation front stator magnetic linkage is calculated as follows shown in formula α, beta-axis component, according to the voltage model of magnetic flux observation as the formula (4):

$\left\{\begin{array}{c}{\mathrm{\ψ}}_{\mathrm{s\α}}=\∫(u_{\mathrm{s\α}}-R_s{i}_{\mathrm{s\α}})\mathrm{dt}\\ {\mathrm{\ψ}}_{\mathrm{s\β}}=\∫(u_{\mathrm{s\β}}-R_s{i}_{\mathrm{s\β}})\mathrm{dt}\end{array}\right.---\left(4\right)$

U in formula _{s α}, u _{s β}---alpha-beta axle stator voltage; i _{s α}, i _{s β}---alpha-beta axle stator current; R _s---stator resistance.

Because pure integration exists initial phase and the saturated problem of integration, the specific implementation of stator flux often adopts the low pass filter with feedforward compensation to replace pure integration, as shown in Figure 1.

2) calculating of stator magnetic flux offset angle tolerance

Stator magnetic flux angular errors is because current time angle used is that to calculate gained stator magnetic flux angle previous interrupt cycle caused, so angular error amount is determined by the time difference of two interrupt cycles and the rotary speed of stator field.The time difference of two interrupt cycles

the rotary speed of stator field is

therefore flux compensation angular metric is

$\mathrm{\Δ\θ}={\mathrm{\ω}}_s\mathrm{\Δt}=\frac{\mathrm{\π}\×n\×n_p}{30f_s}\mathrm{rad}---\left(5\right)$

F wherein _sfor interruption frequency, n is motor speed, n _pfor motor number of pole-pairs.

3) the rear stator magnetic linkage of compensation is in the calculating of α, beta-axis component

After compensation stator magnetic linkage in the computing formula of α, beta-axis component as the formula (3),

$\left\{\begin{array}{c}{{\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}}^{\′}={\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}\cos \left(\mathrm{\Δ\θ}\right)-{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}\sin \left(\mathrm{\Δ\θ}\right)\\ {{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}}^{\′}={\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}\sin \left(\mathrm{\Δ\θ}\right)+{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}\cos \left(\mathrm{\Δ\θ}\right)\end{array}\right.---\left(3\right)$

In formula, △ θ is angular error amount, represent respectively stator magnetic linkage after compensation at the component of α, β axle and the stator magnetic linkage before compensation the component at α, β axle.

4) amplitude of stator magnetic flux and phase place

Amplitude and the phase place that according to formula (3), can obtain stator magnetic linkage are

$\left\{\begin{array}{c}{\widehat{\mathrm{\ψ}}}_s=\sqrt{{\left({{\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}}^{\′}\right)}^2+{\left({{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}}^{\′}\right)}^2}\\ \widehat{\mathrm{\θ}}a\tan \left(\frac{{{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}}^{\′}}{{{\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}}^{\′}}\right)\end{array}\right.---\left(6\right)$

Wherein

for observing the stator magnetic linkage amplitude obtaining,

stator magnetic linkage phase place for observation.

This patent is subsidized by national high-tech research Development Technology (863 Program) problem, project number: 2012AA050206.

Claims (3)

1. stator flux orientation vector control apparatus, comprises magnetic flux observation module, it is characterized in that: described magnetic flux observation module comprises angle compensation unit, and after compensation, stator magnetic linkage at the component of α, β axle is $\left\{\begin{array}{c}{{\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}}^{\′}={\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}\cos \left(\mathrm{\Δ\θ}\right)-{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}\sin \left(\mathrm{\Δ\θ}\right)\\ {{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}}^{\′}={\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}\sin \left(\mathrm{\Δ\θ}\right)+{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}\cos \left(\mathrm{\Δ\θ}\right)\end{array}\right.;$

In formula, △ θ is angular error amount,

represent respectively stator magnetic linkage after compensation at the component of α, β axle and the stator magnetic linkage before compensation the component at α, β axle.

2. the angle compensation process of stator flux orientation vector control apparatus, includes magnetic flux observation procedure, it is characterized in that, increases angle compensation link in described magnetic flux observation procedure: after compensation, stator magnetic linkage at the component of α, β axle is $\left\{\begin{array}{c}{{\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}}^{\′}={\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}\cos \left(\mathrm{\Δ\θ}\right)-{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}\sin \left(\mathrm{\Δ\θ}\right)\\ {{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}}^{\′}={\widehat{\mathrm{\ψ}}}_{\mathrm{s\α}}\sin \left(\mathrm{\Δ\θ}\right)+{\widehat{\mathrm{\ψ}}}_{\mathrm{s\β}}\cos \left(\mathrm{\Δ\θ}\right)\end{array}\right.;$ In formula, △ θ is angular error amount,

represent respectively stator magnetic linkage after compensation at the component of α, β axle and the stator magnetic linkage before compensation the component at α, β axle.

3. the angle compensation process of stator flux orientation vector control apparatus according to claim 2, is characterized in that, described angular error calculates by the switching frequency of frequency converter and the rotating speed of motor actual motion

wherein n is motor speed, n _pfor motor number of pole-pairs, f _sswitching frequency for frequency converter.

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