CN102710207A - Self-setting method in vector control system of asynchronous motor - Google Patents

Abstract

The invention relates to a self-setting method in a vector control system of an asynchronous motor, which mainly adopts rotor time constant self testing under the magnetic circuit saturation. The self-setting method aims to achieve the effect of controlling the performance in a speed control system of the vector control asynchronous motor through the rotor time constant self testing under the magnetic circuit saturation. The rotor time constant self testing is carried out through a voltage type inverter. When direct current voltage is excited and added, the current of a rotor circuit of the asynchronous motor is zero, and the current of a stator is a steady-state current value Id. If a transient process occurs in the current of the stator, the current initial value of the rotor circuit is not zero. Therefore, the zero current of a rotor can be determined through the characteristic, so that a rotor time constant is obtained by adopting a least square method. The self-tested rotor time constant particularly considers the measurement and the acquisition of the rotor time constant under the magnetic circuit saturation and the dead-time compensation, so that the performance of the vector control system of the asynchronous motor is improved.

Description

Automatic setting method in a kind of Vector Control for Asynchronous Motor system

Technical field

The present invention relates to electric machines control technology, relate to the automatic setting method in the Vector Control for Asynchronous Motor system.

Background technology

The speed governing of AC asynchronous motor and control technology are with after system controlled by computer and power electronic technology combine; Very big development has been arranged; That past is difficult for measuring or control electromagnetic process; Through on-line measurement, computational analysis and control, can realize the adjusting control of multiple requirement, multiple principle and technical scheme now.Technology such as ac-dc-ac inverter, AC/AC (alternating current) variable-frequency, pulse width modulation, many level provide many new possibilities for the speed governing and the control of alternating current motor.The proposition of the control method that vector control and direct torque control etc. are new and realization are for the asynchronous motor high performance control is laid a good foundation.The performance of Induction Motor Control System depends on the Mathematical Modeling of motor to a great extent, and the precision of the Mathematical Modeling of motor depends on the parameter of motor.Therefore motor parameter confirms it is very important.

Vector control

The electromagnetic relationship of asynchronous motor has the characteristics of multivariable, non-linear, close coupling, makes the control very difficulty that becomes.1971, F.Blaschke proposed asynchronous motor rotor field orientation vector control method, and basic thought comes from the strictness simulation to direct current machine, and the final purpose of vector control is to improve the torque control performance of motor.Vector control is decomposed into excitation component and torque component through the motor field orientation with stator current, controls respectively.

Field oriented induction motor control strategy (vector control) is when realizing the motor torque high performance control, and is very strong to the dependence of motor parameter.General vector control system can't adapt to motor parameter with variations that working conditions change took place such as motor temperature and excitations; The variation of stator and rotor winding resistance Yin Wendu and kelvin effect and changing, and induction reactance receives the influence of the magnetic circuit saturated conditions of main flux and leakage flux.Almost occur from vector control technology one, people just hope to seek a kind of method that can solve the motor parameter variation and guarantee systematic function.

The d-q coordinate system is fixed on the synchronous rotating magnetic field, and the d axle is overlapped with the rotor field direction.Rotor flux ψ _rQ axle component ψ _Rq=0, rotor voltage u _rD, q axle component u _Rd=0, u _Rq=0.Can push away to such an extent that asynchronous motor rotor field orientation vector control equation is following:

$u_{\mathrm{sd}}=R_s{i}_{\mathrm{sd}}+\mathrm{\σ}{L}_s{\mathrm{pi}}_{\mathrm{sd}}+\frac{L_m}{L_r}{\mathrm{p\ψ}}_{\mathrm{rd}}-{\mathrm{\ω}}_s\mathrm{\σ}{L}_s{i}_{\mathrm{sq}}---\left(A\right)$

$u_{\mathrm{sq}}=R_s{i}_{\mathrm{sq}}+\mathrm{\σ}{L}_s{\mathrm{pi}}_{\mathrm{sq}}+{\mathrm{\ω}}_s\frac{L_m}{L_r}{\mathrm{\ψ}}_{\mathrm{rd}}+{\mathrm{\ω}}_s\mathrm{\σ}{L}_s{i}_{\mathrm{sd}}---\left(B\right)$

${\mathrm{\ψ}}_{\mathrm{rd}}=\frac{L_m}{1+{\mathrm{\τ}}_{r}p}{i}_{\mathrm{sd}}---\left(C\right)$

${\mathrm{\ω}}_{\mathrm{sl}}=\frac{L_m}{{\mathrm{\τ}}_r}\frac{i_{\mathrm{sq}}}{{\mathrm{\ψ}}_{\mathrm{rd}}}---\left(D\right)$

$T_e=n_p\frac{L_m}{L_r}{i}_{\mathrm{sq}}{\mathrm{\ψ}}_{\mathrm{rd}}=\frac{n_p}{R_r}{\mathrm{\ψ}}_{\mathrm{rd}}^2{\mathrm{\ω}}_{\mathrm{sl}}---\left(E\right)$

In the formula: u _Sd, u _SqThe d of-stator voltage, q axle component;

i _Sd, i _SqThe d of-stator current, q axle component;

R _sThe every phase resistance of-stator winding;

L _sEach phase self-induction of-stator;

L _rEach phase self-induction of-rotor;

L _mMutual inductance between-stator and rotor;

ω _s-synchronous angular velocity of rotation;

ω _Sl-slip angular velocity;

ψ _Rd-d axle rotor flux;

n _p-number of pole-pairs;

τ _r-rotor time constant, wherein:

T _e-electromagnetic torque;

σ-magnetic leakage factor, wherein:

The p-operator, wherein:

The parameter self-test

The parameter self-test of asynchronous motor: utilize system's its other resources to reach the purpose of parameter of electric machine test through software.Mainly contain dynamic model method and steady-state model method at present.The dynamic model method is under certain assumed condition, derives the motor major parameter by the dynamic mathematical models of asynchronous motor, and real standard, impulse current or the voltage signal that must consider stator voltage, stator current are to measuring the influence that is caused.The steady-state model method is to ask for the parameter of motor stable state equivalent circuit, and M.Depenbrock has provided the whole CALCULATION OF PARAMETERS formula of induction machine.No matter be steady-state model method or dynamic model method, be based on all that some conditions propose, the error of existence is difficult to compensation or proofreaies and correct.

Summary of the invention

For overcoming the above-mentioned defective of prior art, the present invention has designed the automatic setting method in a kind of Vector Control for Asynchronous Motor system.Rotor time constant self-test when this method mainly adopts magnetic circuit saturated.The objective of the invention is to, in vector control induction motor drive system, the rotor time constant self-test through magnetic circuit when saturated is to reach the improvement control performance.

According to an aspect of the present invention, the automatic setting method in the Vector Control for Asynchronous Motor system of the present invention's design, the rotor time constant self-test when adopting magnetic circuit saturated, the rotor time constant self-test when wherein magnetic circuit is saturated can be divided into following two steps:

The 1st step, enforcement principle

Squirrel cage asynchronous motor, rotor are short circuits; Wound rotor asynchronous motor is used in the frequency control, and its rotor also is short circuit; So u _{R α}=u _{R β}=0; Then when stationary rotor, ω _r=0, then the Mathematical Modeling in the asynchronous motor alpha-beta rest frame is:

$\left[\begin{array}{c}{\mathrm{pi}}_{\mathrm{s\α}}\\ {\mathrm{pi}}_{\mathrm{s\β}}\\ {\mathrm{p\ψ}}_{\mathrm{r\α}}^{\′}\\ {\mathrm{p\ψ}}_{\mathrm{r\β}}^{\′}\end{array}\right]=\left[\begin{array}{cccc}\frac{-(R_s+R_r^{\′})}{L_{\mathrm{\σ}}}& 0& \frac{1}{L_{\mathrm{\σ}}{\mathrm{\τ}}_r}& 0\\ 0& \frac{-(R_s+R_r^{\′})}{L_{\mathrm{\σ}}}& 0& \frac{1}{L_{\mathrm{\σ}}{\mathrm{\τ}}_r}\\ R_r^{\′}& 0& -\frac{1}{{\mathrm{\τ}}_r^{\′}}& 0\\ 0& R_r^{\′}& 0& -\frac{1}{{\mathrm{\τ}}_r^{\′}}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{s\α}}\\ i_{\mathrm{s\β}}\\ {\mathrm{\ψ}}_{\mathrm{r\α}}^{\′}\\ {\mathrm{\ψ}}_{\mathrm{r\β}}^{\′}\end{array}\right]+\left[\begin{array}{cc}\frac{1}{L_{\mathrm{\σ}}}& 0\\ 0& \frac{1}{L_{\mathrm{\σ}}}\\ 0& 0\\ 0& 0\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{s\α}}\\ u_{\mathrm{s\β}}\end{array}\right]---\left(1\right)$

In the formula: L _σ-stator leakage inductance, L _σ=σ L _s

i _{S α}, i _{S β}The α of-stator current, beta-axis component;

u _{S α}, u _{S β}The α of-stator voltage, beta-axis component;

- converted to the stator side rotor flux α, β-axis component;

-convert every phase resistance of rotor of stator side,

-convert rotor flux of stator side,

-convert rotor time constant of stator side.

Then: $\left\{\begin{array}{c}{L}_{\mathrm{\σ}}{\mathrm{Pi}}_{\mathrm{S\α}}=-(R_s+R_r^{\′})i_{\mathrm{S\α}}+\frac{1}{{\mathrm{\τ}}_r}{\mathrm{\ψ}}_{\mathrm{R\α}}^{\′}+u_{\mathrm{S\α}}\\ L_{\mathrm{\σ}}{\mathrm{Pi}}_{\mathrm{S\β}}=-(R_s+R_r^{\′})i_{\mathrm{S\β}}+\frac{1}{{\mathrm{\τ}}_r}{\mathrm{\ψ}}_{\mathrm{R\β}}^{\′}+u_{\mathrm{S\β}}\\ {\mathrm{P\ψ}}_{\mathrm{R\α}}^{\′}=R_r^{\′}{i}_{\mathrm{S\α}}-\frac{1}{{\mathrm{\τ}}_r^{\′}}{\mathrm{\ψ}}_{\mathrm{R\α}}^{\′}\\ {\mathrm{P\ψ}}_{\mathrm{R\β}}^{\′}=R_r^{\′}{i}_{\mathrm{S\β}}-\frac{1}{{\mathrm{\τ}}_r^{\′}}{\mathrm{\ψ}}_{\mathrm{R\β}}^{\′}\end{array}\right.---\left(2\right)$

The relation of stator voltage component, stator current component is in stator voltage, stator current and the alpha-beta rest frame:

$\left[\begin{array}{c}{u}_A\\ u_B\\ u_C\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{cc}1& 0\\ -\frac{1}{2}& \frac{\sqrt{3}}{2}\\ -\frac{1}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{s\α}}\\ u_{\mathrm{s\β}}\end{array}\right],$ $\left[\begin{array}{c}{i}_A\\ i_B\\ i_C\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{cc}1& 0\\ -\frac{1}{2}& \frac{\sqrt{3}}{2}\\ -\frac{1}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{s\α}}\\ i_{\mathrm{s\β}}\end{array}\right]---\left(3\right)$

In the formula: u _A, u _B, u _C-A, B, C threephase stator voltage;

i _A, i _B, i _C-A, B, C threephase stator electric current.

According to (3) Shi Kede: $\left\{\begin{array}{c}{u}_{\mathrm{S\α}}=\sqrt{\frac{3}{2}}{u}_A\\ i_{\mathrm{S\α}}=\sqrt{\frac{3}{2}}{i}_A\end{array}\right.---\left(4\right)$

Having only a phase input voltage when asynchronous motor stator voltage input mode is direct current, like u _A=u _dAnd u (t), _B=u _C=0; Can know in the alpha-beta rest frame this moment stator voltage component (u according to coordinate transform _{S α}, u _{S β}) be:

$\left\{\begin{array}{c}{u}_{\mathrm{s\α}}\left(t\right)=\sqrt{\frac{2}{3}}{u}_d\left(t\right)\\ u_{\mathrm{s\β}}\left(t\right)=0\end{array}\right.---\left(5\right)$

In the formula: u _d(t)-direct voltage.

At this moment, if asynchronous motor is static, ω _r=0, in the alpha-beta rest frame, β shaft current i _β(t)=0.

The 2nd step, rotor time constant self-test when magnetic circuit is saturated

(1) the DC test signal chooses

Asynchronous motor stator current i behind the adding d. c. voltage signal _{S α}Steady-state value be the asynchronous motor rated current

Confirm that through the output voltage of regulation voltage type inverter stator current is stable at I _d

(2) the sinusoidal voltage test signal chooses

The output of regulation voltage type inverter produces the sinusoidal low-frequency current signal of adjustable amplitude value, fixed-frequency in the asynchronous motor stator winding; The magnitude scope of electric current is 0.5-4 a times of its rated value, and frequency is 5-10Hz;

(3) loop test

Apply sinusoidal current excitation i to the asynchronous motor stator loop _{S α}=I _SiSin ω t, record I _SiValue; The decline of stator current positive half period equals steady-state value I in the district _dThe time, encourage moment to switch to the direct voltage excitation sinusoidal current; Real-time sampling stator current i under the direct voltage excitation _{S α}, and write down itself and steady-state value I _dMaximum deviation Δ I _SiAbove process repeats repeatedly, thereby can obtain one group of test data, i.e. I _Si, Δ I _Si

(4) dead-time compensation

In order to reduce the stator voltage distortion that Dead Time causes, adopted the dead area compensation algorithm; As stator current i _A＞0 o'clock, because the existence of Dead Time causes the output voltage of voltage source inverter to reduce; For compensated voltage drop, need the bucking voltage value suc as formula (6):

$\mathrm{\Δu}=2\frac{T_d}{T}{V}_{\mathrm{dc}}---\left(6\right)$

In the formula: T _d-Dead Time;

T-modulates wave period;

-1≤V _dc≤1。

Therefore, the inverter output voltage offset is 2 Δ u.

(5) magnetic circuit is saturated

After magnetic circuit is saturated, continue to strengthen exciting current, test;

(6) least square method

The electric current of switching instant does

I _d＝I _sisinωt＝I _si?sin(π-θ _i)(7)

Through analyzing, formula (8) can get:

y _i＝a?cosθ _i-bsinθ _i (8)

In the formula: y _i=Δ I _Si/ I _Si

a＝Ksinθ ₀；

b＝Kcosθ ₀；

θ ₀-i _{S α}With

Phase difference.

Parameter a and b can obtain rotor time constant τ through least square method _rCan draw by formula (9):

${\mathrm{\τ}}_r=\frac{1}{\mathrm{\ω}\tan {\mathrm{\θ}}_0}---\left(9\right)$

In the formula: $\mathrm{Tan}{\mathrm{\θ}}_0=\frac{a}{b}=\frac{\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i\mathrm{Cos}{\mathrm{\θ}}_i\right)\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{Sin}}^2{\mathrm{\θ}}_i\right)-\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i\mathrm{Sin}{\mathrm{\θ}}_i\right)\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\mathrm{Sin}{\mathrm{\θ}}_i\mathrm{Cos}{\mathrm{\θ}}_i\right)}{\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i\mathrm{Cos}{\mathrm{\θ}}_i\right)\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\mathrm{Sin}{\mathrm{\θ}}_i\mathrm{Cos}{\mathrm{\θ}}_i\right)-\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i\mathrm{Sin}{\mathrm{\θ}}_i\right)\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\mathrm{Cos}}^2{\mathrm{\θ}}_i\right)}.$

The present invention carries out the rotor time constant self-test through voltage source inverter.The self-test rotor time constant, the measuring of the rotor time constant of especially saturated and dead area compensation at magnetic circuit, thus improve the control performance of system.

Can obtain following beneficial effect through this technology:

When 1, magnetic circuit is saturated, carry out rotor time constant τ through this method _rTest is according to the τ that records _rTry to achieve rotor resistance R _r, test error is less than 5%.

2, use the rotor time constant record, run on magnetic circuit Vector Control for Asynchronous Motor when saturated, compare with traditional Vector Control for Asynchronous Motor, phase current reduces when identical load, so loss is corresponding reduces, and efficient improves.

Description of drawings

Fig. 1 is an asynchronous motor stator voltage input mode sketch map;

Fig. 2 is an asynchronous motor model α subsystem schematic diagram;

Fig. 3 is an asynchronous motor rotor field orientation vector control hardware system sketch map;

Fig. 4 is the rotor time constant test flow chart;

Fig. 5 is the response curve of stator current test signal.

Symbol and variable declaration are following among the figure:

IM: asynchronous motor;

Δ I _Si: stator current transient changing maximum;

u _{S α}, i _{S α}: asynchronous motor α subsystem stator voltage and stator current.

All the other symbols and variable are referring to the explanation in the text.

As shown in the figure; In order clearly to realize the structure of embodiments of the invention, marked specific structure and device in the drawings, but this is merely the signal needs; Be not that intention is limited to the present invention in this ad hoc structure, device and the environment; According to concrete needs, those of ordinary skill in the art can adjust these devices and environment or revise, and adjustment of being carried out or modification still are included in the scope of accompanying Claim.

Embodiment

Protect verification method and demo plant thereof to be described in detail below in conjunction with accompanying drawing and specific embodiment to a kind of chip electrostatic that is used for provided by the invention.Here do simultaneously is that more detailed in order to make embodiment, following embodiment be the best, preferred embodiment, also can adopt other alternative and implements for some known technology those skilled in the art with explanation; And accompanying drawing part only is in order to describe embodiment more specifically, and is not intended to the present invention is carried out concrete qualification.

The present invention contain any on marrow of the present invention and scope, make substitute, modification, equivalent method and scheme.Understand for the public is had completely the present invention, in the following preferred embodiment of the present invention, specified concrete details, and do not had the description of these details also can understand the present invention fully for a person skilled in the art.In addition, for fear of essence of the present invention is caused unnecessary obscuring, do not specify well-known method, process, flow process, element and circuit etc.

Rotor time constant self-test when the automatic setting method in the Vector Control for Asynchronous Motor of the present invention system mainly adopts magnetic circuit saturated, wherein Fig. 3 is a hardware system structure block diagram of the present invention.Experiment hardware using voltage source inverter of the present invention wherein adopts the C Programming with Pascal Language.This system hardware part is mainly by AC power, rectification unit, filter unit, and voltage source inverter, the electric current and voltage detecting unit, the DSP control unit is formed.

Rotor time constant self-test when wherein magnetic circuit is saturated can be divided into following two steps:

The 1st step, enforcement principle

Squirrel cage asynchronous motor, rotor are short circuits.Wound rotor asynchronous motor is used in the frequency control, and its rotor also is short circuit.So u _{R α}=u _{R β}=0.Then when stationary rotor, ω _r=0, then the Mathematical Modeling in the asynchronous motor alpha-beta rest frame is:

$\left[\begin{array}{c}{\mathrm{pi}}_{\mathrm{s\α}}\\ {\mathrm{pi}}_{\mathrm{s\β}}\\ {\mathrm{p\ψ}}_{\mathrm{r\α}}^{\′}\\ {\mathrm{p\ψ}}_{\mathrm{r\β}}^{\′}\end{array}\right]=\left[\begin{array}{cccc}\frac{-(R_s+R_r^{\′})}{L_{\mathrm{\σ}}}& 0& \frac{1}{L_{\mathrm{\σ}}{\mathrm{\τ}}_r}& 0\\ 0& \frac{-(R_s+R_r^{\′})}{L_{\mathrm{\σ}}}& 0& \frac{1}{L_{\mathrm{\σ}}{\mathrm{\τ}}_r}\\ R_r^{\′}& 0& -\frac{1}{{\mathrm{\τ}}_r^{\′}}& 0\\ 0& R_r^{\′}& 0& -\frac{1}{{\mathrm{\τ}}_r^{\′}}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{s\α}}\\ i_{\mathrm{s\β}}\\ {\mathrm{\ψ}}_{\mathrm{r\α}}^{\′}\\ {\mathrm{\ψ}}_{\mathrm{r\β}}^{\′}\end{array}\right]+\left[\begin{array}{cc}\frac{1}{L_{\mathrm{\σ}}}& 0\\ 0& \frac{1}{L_{\mathrm{\σ}}}\\ 0& 0\\ 0& 0\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{s\α}}\\ u_{\mathrm{s\β}}\end{array}\right]---\left(1\right)$

In the formula: L _σ-stator leakage inductance, L _σ=σ L _s

i _{S α}, i _{S β}The α of-stator current, beta-axis component;

u _{S α}, u _{S β}The α of-stator voltage, beta-axis component;

-convert α, beta-axis component of the rotor flux of stator side;

R _sThe every phase resistance of-stator;

-convert every phase resistance of rotor of stator side,

-convert rotor flux of stator side,

τ _r-rotor time constant,

-convert rotor time constant of stator side.

Then: $\left\{\begin{array}{c}{L}_{\mathrm{\σ}}{\mathrm{Pi}}_{\mathrm{S\α}}=-(R_s+R_r^{\′})i_{\mathrm{S\α}}+\frac{1}{{\mathrm{\τ}}_r}{\mathrm{\ψ}}_{\mathrm{R\α}}^{\′}+u_{\mathrm{S\α}}\\ L_{\mathrm{\σ}}{\mathrm{Pi}}_{\mathrm{S\β}}=-(R_s+R_r^{\′})i_{\mathrm{S\β}}+\frac{1}{{\mathrm{\τ}}_r}{\mathrm{\ψ}}_{\mathrm{R\β}}^{\′}+u_{\mathrm{S\β}}\\ {\mathrm{P\ψ}}_{\mathrm{R\α}}^{\′}=R_r^{\′}{i}_{\mathrm{S\α}}-\frac{1}{{\mathrm{\τ}}_r^{\′}}{\mathrm{\ψ}}_{\mathrm{R\α}}^{\′}\\ {\mathrm{P\ψ}}_{\mathrm{R\β}}^{\′}=R_r^{\′}{i}_{\mathrm{S\β}}-\frac{1}{{\mathrm{\τ}}_r^{\′}}{\mathrm{\ψ}}_{\mathrm{R\β}}^{\′}\end{array}\right.---\left(2\right)$

Stator voltage (u _A, u _B, u _C), stator current (i _A, i _B, i _C) with the alpha-beta rest frame in stator voltage component (u _{S α}, u _{S β}), stator current component (i _{S α}, i _{S β}) relation be:

$\left[\begin{array}{c}{u}_A\\ u_B\\ u_C\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{cc}1& 0\\ -\frac{1}{2}& \frac{\sqrt{3}}{2}\\ -\frac{1}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{s\α}}\\ u_{\mathrm{s\β}}\end{array}\right],$ $\left[\begin{array}{c}{i}_A\\ i_B\\ i_C\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{cc}1& 0\\ -\frac{1}{2}& \frac{\sqrt{3}}{2}\\ -\frac{1}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{s\α}}\\ i_{\mathrm{s\β}}\end{array}\right]---\left(3\right)$

In the formula: u _A, u _B, u _C-A, B, C threephase stator voltage;

i _A, i _B, i _C-A, B, C threephase stator electric current.

According to (3) Shi Kede: $\left\{\begin{array}{c}{u}_{\mathrm{S\α}}=\sqrt{\frac{3}{2}}{u}_A\\ i_{\mathrm{S\α}}=\sqrt{\frac{3}{2}}{i}_A\end{array}\right.---\left(4\right)$

When asynchronous motor stator voltage input mode was as shown in Figure 1, promptly having only a phase input voltage was direct current, like u _A=u _dAnd u (t), _B=u _C=0.Can know in the alpha-beta rest frame this moment stator voltage component (u according to coordinate transform _{S α}, u _{S β}) be:

$\left\{\begin{array}{c}{u}_{\mathrm{s\α}}\left(t\right)=\sqrt{\frac{2}{3}}{u}_d\left(t\right)\\ u_{\mathrm{s\β}}\left(t\right)=0\end{array}\right.---\left(5\right)$

In the formula: u _d(t)-direct voltage.

At this moment, if asynchronous motor is static, ω _r=0, at alpha-beta rest frame, i _β(t)=0.

Therefore it is as shown in Figure 2 to get asynchronous motor model α subsystem, and system equation is a second order differential equation, and steady-state component I is arranged the time response of stator current _dAnd transient component.After transient process finished, transient component approached zero with unlimited, and stator current will be stable at steady-state component.When the initial value of stator current equals steady-state value I _dSituation under apply direct voltage excitation, then can eliminate initial value and steady-state value I by stator current _dThe transient component that causes, then the stator current expression formula is made up of the transient component that steady-state value and rotor loop initial value cause.When the direct voltage excitation adds fashionable rotor loop electric current is zero, does not then have transient component in the stator current, and promptly stator current maintains steady-state current value I when the direct voltage excitation drops into _dIf transient process has appearred in stator current, then rotor loop electric current initial value is non-vanishing.Therefore can utilize these characteristics to confirm the rotor current zero crossing, thereby obtain rotor time constant according to least square method.

The 2nd step, rotor time constant self-test (test flow chart is as shown in Figure 4) when magnetic circuit is saturated

(1) the DC test signal chooses

Asynchronous motor stator current i behind the adding d. c. voltage signal _{S α}Steady-state value, generally elect the asynchronous motor rated current as

Confirm that through the output voltage of suitable regulation voltage type inverter stator current is stable at I _d

(2) the sinusoidal voltage test signal chooses

The output of regulation voltage type inverter produces the sinusoidal low-frequency current signal of adjustable amplitude value, fixed-frequency in the asynchronous motor stator winding.The magnitude scope of electric current is 0.5-4 a times of its rated value, and frequency is (5-10) Hz.

(3) loop test

Apply sinusoidal current excitation i to the asynchronous motor stator loop _{S α}=I _SiSin ω t, record I _SiValue; The decline of stator current positive half period equals steady-state value I in the district _dThe time, encourage (sinusoidal input voltage) moment to switch to the direct voltage excitation sinusoidal current; Real-time sampling stator current i under the direct voltage excitation _{S α}, and write down itself and steady-state value I _dMaximum deviation Δ I _SiAbove process repeats repeatedly, thereby can obtain one group of test data (I _Si, Δ I _Si).

(4) dead-time compensation

In order to reduce the stator voltage distortion that Dead Time causes, adopted the dead area compensation algorithm.As stator current i _A＞0 o'clock, because the existence of Dead Time causes the output voltage of voltage source inverter to reduce.For compensated voltage drop, need the bucking voltage value suc as formula (6):

$\mathrm{\Δu}=2\frac{T_d}{T}{V}_{\mathrm{dc}}---\left(6\right)$

In the formula: T _d-Dead Time;

T-modulates wave period;

-1≤V _dc≤1。

Therefore, the inverter output voltage offset is 2 Δ u.

(5) magnetic circuit is saturated

After magnetic circuit is saturated, continue to strengthen exciting current, test.

(6) least square method

The phase place of the stator current of switching instant is seen Fig. 5, and the electric current of switching instant does

I _d＝I _sisinωt＝I _sisin(π-θ _i)(7)

Through analyzing, formula (8) can get:

y _i＝acosθ _i-bsinθ _i (8)

In the formula: y _i=Δ I _Si/ I _Si

a＝K?sinθ ₀；

b＝K?cosθ ₀；

θ ₀-i _{S α}With Phase difference.

Parameter a and b can obtain rotor time constant τ through least square method _rCan get by (9):

${\mathrm{\τ}}_r=\frac{1}{\mathrm{\ω}\tan {\mathrm{\θ}}_0}---\left(9\right)$

In the formula: θ _i-phase angle;

$\tan {\mathrm{\θ}}_0=\frac{a}{b}=\frac{\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i\cos {\mathrm{\θ}}_i\right)\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\sin }^2{\mathrm{\θ}}_i\right)-\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i\sin {\mathrm{\θ}}_i\right)\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\sin {\mathrm{\θ}}_i\cos {\mathrm{\θ}}_i\right)}{\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i\cos {\mathrm{\θ}}_i\right)\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\sin {\mathrm{\θ}}_i\cos {\mathrm{\θ}}_i\right)-\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i\sin {\mathrm{\θ}}_i\right)\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\cos }^2{\mathrm{\θ}}_i\right)}.$

Above rotor time constant test process is on the control system that voltage source inverter constitutes, to accomplish, and is applied to the induction motor drive system of the vector control of and dead area compensation strategy saturated based on magnetic circuit.

What should explain at last is; Above embodiment is only in order to describe technical scheme of the present invention rather than the present technique method is limited; The present invention can extend to other modification, variation, application and embodiment on using, and therefore thinks that all such modifications, variation, application, embodiment are in spirit of the present invention and teachings.

Claims (2)

1. the automatic setting method in the Vector Control for Asynchronous Motor system, the rotor time constant self-test when this method adopts magnetic circuit saturated, the rotor time constant self-test when wherein magnetic circuit is saturated can be divided into following two steps:

The 1st step, enforcement principle

Squirrel cage asynchronous motor, rotor are short circuits; Wound rotor asynchronous motor is used in the frequency control, and its rotor also is short circuit; So u _{R α}=u _{R β}=0; Then when stationary rotor, ω _r=0, then the Mathematical Modeling in the asynchronous motor alpha-beta rest frame is:

$\left[\begin{array}{c}{\mathrm{pi}}_{\mathrm{s\α}}\\ {\mathrm{pi}}_{\mathrm{s\β}}\\ {\mathrm{p\ψ}}_{\mathrm{r\α}}^{\′}\\ {\mathrm{p\ψ}}_{\mathrm{r\β}}^{\′}\end{array}\right]=\left[\begin{array}{cccc}\frac{-(R_s+R_r^{\′})}{L_{\mathrm{\σ}}}& 0& \frac{1}{L_{\mathrm{\σ}}{\mathrm{\τ}}_r}& 0\\ 0& \frac{-(R_s+R_r^{\′})}{L_{\mathrm{\σ}}}& 0& \frac{1}{L_{\mathrm{\σ}}{\mathrm{\τ}}_r}\\ R_r^{\′}& 0& -\frac{1}{{\mathrm{\τ}}_r^{\′}}& 0\\ 0& R_r^{\′}& 0& -\frac{1}{{\mathrm{\τ}}_r^{\′}}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{s\α}}\\ i_{\mathrm{s\β}}\\ {\mathrm{\ψ}}_{\mathrm{r\α}}^{\′}\\ {\mathrm{\ψ}}_{\mathrm{r\β}}^{\′}\end{array}\right]+\left[\begin{array}{cc}\frac{1}{L_{\mathrm{\σ}}}& 0\\ 0& \frac{1}{L_{\mathrm{\σ}}}\\ 0& 0\\ 0& 0\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{s\α}}\\ u_{\mathrm{s\β}}\end{array}\right]---\left(1\right)$

In the formula: L _σ-stator leakage inductance, L _σ=σ L _s

i _{S α}, i _{S β}The α of-stator current, beta-axis component;

u _{S α}, u _{S β}The α of-stator voltage, beta-axis component;

-convert α, beta-axis component of the rotor flux of stator side;

R _sThe every phase resistance of-stator;

-convert every phase resistance of rotor of stator side,

-convert rotor flux of stator side,

τ _r-rotor time constant,

-convert rotor time constant of stator side.

Then: $\left\{\begin{array}{c}{L}_{\mathrm{\σ}}{\mathrm{Pi}}_{\mathrm{S\α}}=-(R_s+R_r^{\′})i_{\mathrm{S\α}}+\frac{1}{{\mathrm{\τ}}_r}{\mathrm{\ψ}}_{\mathrm{R\α}}^{\′}+u_{\mathrm{S\α}}\\ L_{\mathrm{\σ}}{\mathrm{Pi}}_{\mathrm{S\β}}=-(R_s+R_r^{\′})i_{\mathrm{S\β}}+\frac{1}{{\mathrm{\τ}}_r}{\mathrm{\ψ}}_{\mathrm{R\β}}^{\′}+u_{\mathrm{S\β}}\\ {\mathrm{P\ψ}}_{\mathrm{R\α}}^{\′}=R_r^{\′}{i}_{\mathrm{S\α}}-\frac{1}{{\mathrm{\τ}}_r^{\′}}{\mathrm{\ψ}}_{\mathrm{R\α}}^{\′}\\ {\mathrm{P\ψ}}_{\mathrm{R\β}}^{\′}=R_r^{\′}{i}_{\mathrm{S\β}}-\frac{1}{{\mathrm{\τ}}_r^{\′}}{\mathrm{\ψ}}_{\mathrm{R\β}}^{\′}\end{array}\right.---\left(2\right)$

Stator voltage (u _A, u _B, u _C), stator current (i _A, i _B, i _C) with the alpha-beta rest frame in stator voltage component (u _{S α}, u _{S β}), stator current component (i _{S α}, i _{S β}) relation be:

$\left[\begin{array}{c}{u}_A\\ u_B\\ u_C\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{cc}1& 0\\ -\frac{1}{2}& \frac{\sqrt{3}}{2}\\ -\frac{1}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{u}_{\mathrm{s\α}}\\ u_{\mathrm{s\β}}\end{array}\right],$ $\left[\begin{array}{c}{i}_A\\ i_B\\ i_C\end{array}\right]=\sqrt{\frac{2}{3}}\left[\begin{array}{cc}1& 0\\ -\frac{1}{2}& \frac{\sqrt{3}}{2}\\ -\frac{1}{2}& -\frac{\sqrt{3}}{2}\end{array}\right]\left[\begin{array}{c}{i}_{\mathrm{s\α}}\\ i_{\mathrm{s\β}}\end{array}\right]---\left(3\right)$

In the formula: u _A, u _B, u _C-A, B, C threephase stator voltage;

i _A, i _B, i _C-A, B, C threephase stator electric current.

According to (3) Shi Kede: $\left\{\begin{array}{c}{u}_{\mathrm{S\α}}=\sqrt{\frac{3}{2}}{u}_A\\ i_{\mathrm{S\α}}=\sqrt{\frac{3}{2}}{i}_A\end{array}\right.---\left(4\right)$

Having only a phase input voltage when asynchronous motor stator voltage input mode is direct current, like u _A=u _dAnd u (t), _B=u _C=0; Can know in the alpha-beta rest frame this moment stator voltage component (u according to coordinate transform _{S α}, u _{S β}) be:

$\left\{\begin{array}{c}{u}_{\mathrm{s\α}}\left(t\right)=\sqrt{\frac{2}{3}}{u}_d\left(t\right)\\ u_{\mathrm{s\β}}\left(t\right)=0\end{array}\right.---\left(5\right)$

In the formula: u _d(t)-direct voltage.

At this moment, if asynchronous motor is static, ω _r=0, at alpha-beta rest frame, i _β(t)=0;

The 2nd step, rotor time constant self-test when magnetic circuit is saturated

(1) the DC test signal chooses

Asynchronous motor stator current i behind the adding d. c. voltage signal _{S α}Steady-state value be the asynchronous motor rated current

Confirm that through the output voltage of regulation voltage type inverter stator current is stable at I _d

(2) the sinusoidal voltage test signal chooses

The output of regulation voltage type inverter produces the sinusoidal low-frequency current signal of adjustable amplitude value, fixed-frequency in the asynchronous motor stator winding; The magnitude scope of electric current is 0.5-4 a times of its rated value, and frequency is 5-10Hz;

(3) loop test

Apply sinusoidal current excitation i to the asynchronous motor stator loop _{S α}=I _SiSin ω t, record I _SiValue; The decline of stator current positive half period equals steady-state value I in the district _dThe time, encourage moment to switch to the direct voltage excitation sinusoidal current; Real-time sampling stator current i under the direct voltage excitation _{S α}, and write down itself and steady-state value I _dMaximum deviation Δ I _SiAbove process repeats repeatedly, thereby can obtain one group of test data, i.e. I _Si, Δ I _Si

(4) dead-time compensation

In order to reduce the stator voltage distortion that Dead Time causes, adopted the dead area compensation algorithm; As stator current i _A＞0 o'clock, because the existence of Dead Time causes the output voltage of voltage source inverter to reduce; For compensated voltage drop, need the bucking voltage value suc as formula (6):

$\mathrm{\Δu}=2\frac{T_d}{T}{V}_{\mathrm{dc}}---\left(6\right)$

In the formula: T _d-Dead Time;

T-modulates wave period;

-1≤V _dc≤1。

Therefore, the inverter output voltage offset is 2 Δ u;

(5) magnetic circuit is saturated

After magnetic circuit is saturated, continue to strengthen exciting current, test;

(6) least square method

The electric current of switching instant does

I _d＝I _sisinωt＝I _sisin(π-θ _i)(7)

Through analyzing, formula (8) can get:

y _i＝acosθ _i-bsinθ _i (8)

In the formula: y _i=Δ I _Si/ I _Si

a＝K?sinθ ₀；

b＝K?cosθ ₀；

θ ₀-i _{S α}With Phase difference.

Parameter a and b can obtain rotor time constant τ through least square method _rCan draw by formula (9):

${\mathrm{\τ}}_r=\frac{1}{\mathrm{\ω}\tan {\mathrm{\θ}}_0}---\left(9\right)$

In the formula: θ _i-phase angle;

$\tan {\mathrm{\θ}}_0=\frac{a}{b}=\frac{\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i\cos {\mathrm{\θ}}_i\right)\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\sin }^2{\mathrm{\θ}}_i\right)-\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i\sin {\mathrm{\θ}}_i\right)\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\sin {\mathrm{\θ}}_i\cos {\mathrm{\θ}}_i\right)}{\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i\cos {\mathrm{\θ}}_i\right)\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}\sin {\mathrm{\θ}}_i\cos {\mathrm{\θ}}_i\right)-\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{y}_i\sin {\mathrm{\θ}}_i\right)\left(\underset{i=1}{\overset{n}{\mathrm{\Σ}}}{\cos }^2{\mathrm{\θ}}_i\right)}.$

2. method according to claim 1 is characterized in that: said sinusoidal current is actuated to sinusoidal input voltage.

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