CN102857159A - Excitation-varied synchronous motor MTPA (Maximum Torque Per Ampere) control method based on fitting of binary quadratic function - Google Patents

Abstract

The invention relates to an excitation-varied synchronous motor MTPA control method based on fitting of a binary quadratic function, and provides a method for carrying out rectangular axis current function fitting by the binary quadratic function aiming at a rectangular axis current calculating module in a control structure graph (3), and the method comprises the following steps of: respectively fitting the rectangular axis current functions into the binary quadratic functions about Te and psi f, and finally finishing controlling of maximum torque per ampere of the excitation-varied synchronous motor. The excitation-varied synchronous motor MTPA control method based on fitting of the binary quadratic function has the following beneficial effects: (1), the problem that the rectangular axis current function is difficultly acquired in the MTPA controlling of the excitation-varied synchronous motor is solved by carrying out rectangular axis current function fitting through a fitting method of the binary quadratic function; and (2), the method of the binary quadratic function in the method adopted by the invention is simple and effective, and compared with the other two-dimensional look-up table methods, the method has the superiorities of good fitting degree and small occupied memory.

Description

Change excitation magnetic synchronization motor MTPA control method based on the Binary quadratic functions match

Technical field

The present invention relates to a kind of change excitation magnetic synchronization motor maximum torque per ampere control method, be that a kind of synchronous machine that changes for exciting current utilizes multi-thread (dihydric phenol) approximating method to carry out the method for breakdown torque current ratio (MTPA) control, belong to alternating current machine drive technology field.

Background technology

The starting/generating integrated be an important development direction of following aviation AC power supply system.At present China's aircraft AC power supply system mostly adopts three grades of formula brushless synchronous machines (theory diagram is seen Fig. 1) as generator, and such generator is without the function of starting aero-engine, and engine is started by starter independently.Such engine-power-supply system comprises two cover motors, so that its volume and weight is larger, and system complex, reliability reduces.If can on the basis of original three grades of formula no-brush synchronous generators, make it operate in the starting that motoring condition is finished engine by control, namely realize starting/generating integrated, just can save special starter, alleviate airborne weight and system bulk.But this motor is mainly and satisfies electricity generate function design, and there are the following problems when motoring condition: 1) during static and lower-speed state, the exciter output voltage is lower, the main generator excitation electric current is less, has a strong impact on the loaded starting ability of main generator; 2) along with the rising of motor speed, the exciter output voltage increases gradually, and the main generator excitation electric current also increases gradually, and namely the main generator excitation electric current is among the variation in motor starting process always.

From electric machine structure, main generator is the electric field excitation salient pole synchronous machine.In order to improve the load capacity of main generator when the static and low speed, should select the maximum torque per ampere control strategy.For permagnetic synchronous motor or the constant electric excitation synchronous motor of exciting current, its excitation flux linkage or exciting current remain unchanged, i.e. electromagnetic torque equation T _e=n _p(Ψ _di _q-Ψ _qi _d)=n _p[Ψ _fi _q+ (L _d-L _q) i _di _q] in ψ _fBe constant, so control is exactly the nonlinear programming problem as follows of finishing of wanting real-time for the MTPA of this type of motor, in the hope of the reference value of rectangular axis electric current:

$\left\{\begin{array}{c}\min ={{\mathrm{<figure-callout\; id="2"\; label="i\; d"\; filenames="HDA00002164399600031.png"\; state="\{\{state\}\}">i</figure-callout>}}_d}^2+{i_q}^2\\ T_e=n_p[{\mathrm{\&Psi;}}_f{i}_q+(L_d-L_q)i_d{i}_q]\end{array}\right.---\left(1\right)$

By to the finding the solution of following formula, can obtain to satisfy the i of MTPA control _d, i _qWith T _eRelation:

$\left\{\begin{array}{c}{i}_d=f_1\left(T_e\right)\\ i_q=f_2\left(T_e\right)\end{array}\right.---\left(2\right)$

Function f in the formula (2) ₁And f ₂The exact analytic expression all be difficult to determine, so generally adopt secondary or cubic polynomial to carry out match, utilize polynomial fitting to build the rectangular axis electric current and resolve module, finish the MTPA control of motor.

When the synchronous machinery excitation electric current changes with motor speed, when namely excitation flux linkage is non-constant, because the ψ in the formula (1) _fBe variable, therefore the i that is solved by formula (1) _d, i _qExpression formula will become:

$\left\{\begin{array}{c}{i}_d=f_1(T_e,{\mathrm{\&Psi;}}_f)\\ i_q=f_2(T_e,{\mathrm{\&Psi;}}_f)\end{array}\right.---\left(3\right)$

For formula (3), function f ₁And f ₂The exact analytic expression more be difficult to determine, and can not adopt simple secondary or cubic polynomial to carry out match.

Summary of the invention

The technical problem that solves

For fear of the deficiencies in the prior art part, the present invention proposes a kind of change excitation magnetic synchronization motor MTPA control method based on the Binary quadratic functions match, compare with the permanent excitation magnetic synchronization motor MTPA control of tradition, the maximum difference that becomes excitation magnetic synchronization motor MTPA control is that the MTPA of rectangular axis electric current resolves module.

Thought of the present invention is: in becoming excitation magnetic synchronization motor MTPA control, the MTPA of rectangular axis electric current resolves module and need to make amendment, final control structure figure wherein is the MTPA control structure figure of synchronous machine under traditional permanent excitation by the part of dotted line as shown in Figure 2.

Technical scheme

A kind of change excitation magnetic synchronization motor MTPA control method based on the Binary quadratic functions match, it is characterized in that: resolve the problem that rectangular axis current function expression formula is difficult to determine in the module for rectangular axis electric current MTPA, adopt the Binary quadratic functions approximating method to carry out the current function match, in take fitting function as the Foundation maximum torque per ampere control rectangular axis electric current resolve module, concrete steps are as follows:

Step 1: MTPA resolves in the module at the rectangular axis electric current, to torque specified rate T _eWith excitation flux linkage Ψ _fCarrying out equidistant discretization processes;

Step 2: find the solution all torque specified rate T _eWith excitation flux linkage Ψ _fThe nonlinear programming problem of the rectangular axis electric current that combination is corresponding $\left\{\begin{array}{c}\min ={{\mathrm{<figure-callout\; id="2"\; label="i\; d"\; filenames="HDA00002164399600031.png"\; state="\{\{state\}\}">i</figure-callout>}}_d}^2+{i_q}^2\\ T_e=n_p[{\mathrm{\&Psi;}}_f{i}_q+(L_d-L_q)i_d{i}_q]\end{array}\right.,$ Result of calculation is expressed as the binary discrete function $\left\{\begin{array}{c}{i}_d=f_1(T_e,{\mathrm{\&Psi;}}_f)\\ i_q=f_2\left(T_e{,\mathrm{\&Psi;}}_f\right)\end{array}\right.,$ Wherein: i _dBe direct-axis current, i _qFor handing over shaft current, n _pBe motor number of pole-pairs, L _dBe d-axis inductance, L _qFor handing over axle inductance, f ₁, f ₂For about T _eAnd Ψ _fBinary discrete function formula;

Step 3: for the binary discrete function $\left\{\begin{array}{c}{i}_d=f_1(T_e,{\mathrm{\&Psi;}}_f)\\ i_q=f_2\left(T_e{,\mathrm{\&Psi;}}_f\right)\end{array}\right.,$ Adopting the Binary quadratic functions approximating method to carry out Function Fitting gets $\left\{\begin{array}{c}{i}_d=S_d(T_e,{\mathrm{\&Psi;}}_f)\\ i_q=S_q(T_e,{\mathrm{\&Psi;}}_f)\end{array}\right.,$ S wherein _d, S _qFor about T _eAnd Ψ _fDihydric phenol continuous function formula;

Step 4: with Binary quadratic functions $\left\{\begin{array}{c}{i}_d=S_d(T_e,{\mathrm{\&Psi;}}_f)\\ i_q=S_q(T_e,{\mathrm{\&Psi;}}_f)\end{array}\right.$ Resolve module for Foundation becomes excitation magnetic synchronization motor MTPA control rectangular axis electric current, obtain the d shaft current i that control becomes excitation magnetic synchronization motor _dWith q shaft current i _q

Beneficial effect

A kind of change excitation magnetic synchronization motor MTPA control method based on the Binary quadratic functions match that the present invention proposes, resolve module for the rectangular axis electric current among the control structure figure, propose a kind of method that adopts Binary quadratic functions to carry out the match of rectangular axis current function, the rectangular axis current function that is about in the formula (3) fits to about T respectively _eAnd Ψ _fBinary quadratic functions, finally finish the maximum torque per ampere control that becomes excitation magnetic synchronization motor.

The inventive method has following beneficial effect:

1) adopts the Binary quadratic functions approximating method to carry out the match of rectangular axis current function, solved the problem that the rectangular axis current function is difficult to obtain in the change excitation magnetic synchronization motor MTPA control;

2) the Binary quadratic functions approximating method that adopts in the inventive method is simply effective, than additive methods such as two-dimentional look-up tables, has fitting degree good, the advantage that shared internal memory is little.

Description of drawings

Fig. 1: the three grades of brushless synchronous initiation of formula/power generation system structure figure;

Fig. 2: become excitation magnetic synchronization motor maximum torque per ampere control structure chart;

Fig. 3: exciting current is with the motor speed change curve;

Fig. 4: direct-axis current dihydric phenol matched curve diagram of block;

Fig. 5: hand over shaft current dihydric phenol matched curve diagram of block;

Fig. 6: become excitation magnetic synchronization motor maximum torque per ampere control simulation result.

Embodiment

Now in conjunction with the embodiments, the invention will be further described for accompanying drawing:

Be checking the inventive method, adopt Matlab2008b-Simulink6.0 to carry out simulating, verifying.The electric excitation synchronous motor parameter is in the emulation: number of pole-pairs n _P=3; Stator winding resistance R _s=10.3m Ω; The d-axis inductance L _d=0.63mH; Hand over the axle inductance L _q=0.31mH; Mutual inductance L _m=6mH; Given rotating speed n _N=3000 (r/min).Exciting current with the curve of rotation speed change as shown in Figure 3.Concrete simulated conditions is set as: starting duty is 15Nm, is increased to gradually afterwards 45Nm, and when motor torque reached 2200 (r/min), load descended again gradually, and is stable when being 6Nm to load.

The concrete steps that embodiment comprises are as follows:

Step 1: MTPA resolves in the module at the rectangular axis electric current, to torque specified rate T _eWith excitation flux linkage Ψ _fCarrying out equidistant discretization processes;

Excitation flux linkage Ψ _fExcursion be 0.06 ~ 0.144Wb, the excursion of torque specified rate is 5 ~ 100Nm, so with excitation flux linkage Ψ _fDiscrete is 0.06,0.072,0.084,0.096,0.108,0.12,0.132,0.144, and it is 5,10,15,20,25,30,35,40,45,50,55,60,65,70,75,80,85,90,95,100 that the torque specified rate is dispersed.

Step 2: find the solution all torque specified rate T _eWith excitation flux linkage Ψ _fThe nonlinear programming problem of the rectangular axis electric current that combination is corresponding $\left\{\begin{array}{c}\min ={{\mathrm{<figure-callout\; id="2"\; label="i\; d"\; filenames="HDA00002164399600031.png"\; state="\{\{state\}\}">i</figure-callout>}}_d}^2+{i_q}^2\\ T_e=n_p[{\mathrm{\&Psi;}}_f{i}_q+(L_d-L_q)i_d{i}_q]\end{array}\right.,$ Result of calculation is expressed as the binary discrete function $\left\{\begin{array}{c}{i}_d=f_1(T_e,{\mathrm{\&Psi;}}_f)\\ i_q=f_2\left(T_e{,\mathrm{\&Psi;}}_f\right)\end{array}\right.,$ Wherein: i _dBe direct-axis current, i _qFor handing over shaft current, n _pBe motor number of pole-pairs, L _dBe d-axis inductance, L _qFor handing over axle inductance, f ₁, f ₂For about T _eAnd Ψ _fBinary discrete function formula;

Get different excitation flux linkage Ψ _fWith torque specified rate T _eCombination, totally 160 kinds of situations, substitution rectangular axis current non-linear planning problem $\left\{\begin{array}{c}\min ={{\mathrm{<figure-callout\; id="2"\; label="i\; d"\; filenames="HDA00002164399600031.png"\; state="\{\{state\}\}">i</figure-callout>}}_d}^2+{i_q}^2\\ T_e=n_p[{\mathrm{\&Psi;}}_f{i}_q+(L_d-L_q)i_d{i}_q]\end{array}\right.$ In carry out resolving of rectangular axis electric current, with the form record of result of calculation with two-dimentional form.

Step 3: for the binary discrete function $\left\{\begin{array}{c}{i}_d=f_1(T_e,{\mathrm{\&Psi;}}_f)\\ i_q=f_2\left(T_e{,\mathrm{\&Psi;}}_f\right)\end{array}\right.,$ Adopting the Binary quadratic functions approximating method to carry out Function Fitting gets $\left\{\begin{array}{c}{i}_d=S_d(T_e,{\mathrm{\&Psi;}}_f)\\ i_q=S_q(T_e,{\mathrm{\&Psi;}}_f)\end{array}\right.,$ S wherein _d, S _qFor about T _eAnd Ψ _fDihydric phenol continuous function formula;

Rectangular axis Current calculation value in the step 2 is carried out the Binary quadratic functions match, and fitting result is:

$\left\{\begin{array}{c}{i}_d=6635.3{{\mathrm{\&psi;}}_{\mathrm{<figure-callout\; id="2"\; label="f"\; filenames="HDA00002164399600031.png"\; state="\{\{state\}\}">f</figure-callout>}}}^2+0.0018{T_e}^2-1440.2{\mathrm{\&psi;}}_f+2.82T_e-15.64{\mathrm{\&psi;}}_f\&times;T_e+65.03\\ i_q=2284.8{{\mathrm{\&psi;}}_f}^2-0.0086{T_e}^2-856.19{\mathrm{\&psi;}}_f+3.85T_e-6.751{\mathrm{\&psi;}}_f\&times;T_e+66.52\end{array}\right.$

Binary quadratic functions after the match at the representation of a surface in the three-dimensional system of coordinate shown in Fig. 4,5.

Step 4: with Binary quadratic functions $\left\{\begin{array}{c}{i}_d=S_d(T_e,{\mathrm{\&Psi;}}_f)\\ i_q=S_q(T_e,{\mathrm{\&Psi;}}_f)\end{array}\right.$ Resolve module for Foundation becomes excitation magnetic synchronization motor MTPA control rectangular axis electric current, obtain the d shaft current i that control becomes excitation magnetic synchronization motor _dWith q shaft current i _qOther parts among the control structure figure all with traditional permanent excitation magnetic synchronization motor MTPA control in consistent.

Claims (1)

1. change excitation magnetic synchronization motor MTPA control method based on the Binary quadratic functions match is characterized in that step is as follows:

Step 1: MTPA resolves in the module at the rectangular axis electric current, to torque specified rate T _eWith excitation flux linkage Ψ _fCarrying out equidistant discretization processes;

Step 2: find the solution all torque specified rate T _eWith excitation flux linkage Ψ _fThe nonlinear programming problem of the rectangular axis electric current that combination is corresponding $\left\{\begin{array}{c}\min ={i_d}^2+{i_q}^2\\ T_e=n_p[{\mathrm{\&Psi;}}_f{i}_q+(L_d-L_q)i_d{i}_q]\end{array}\right.,$ Result of calculation is expressed as the binary discrete function $\left\{\begin{array}{c}{i}_d=f_1(T_e,{\mathrm{\&Psi;}}_f)\\ i_q=f_2\left(T_e{,\mathrm{\&Psi;}}_f\right)\end{array}\right.,$ Wherein: i _dBe direct-axis current, i _qFor handing over shaft current, n _pBe motor number of pole-pairs, L _dBe d-axis inductance, L _qFor handing over axle inductance, f ₁, f ₂For about T _eAnd Ψ _fBinary discrete function formula;

Step 3: for the binary discrete function $\left\{\begin{array}{c}{i}_d=f_1(T_e,{\mathrm{\&Psi;}}_f)\\ i_q=f_2\left(T_e{,\mathrm{\&Psi;}}_f\right)\end{array}\right.,$ Adopting the Binary quadratic functions approximating method to carry out Function Fitting gets $\left\{\begin{array}{c}{i}_d=S_d(T_e,{\mathrm{\&Psi;}}_f)\\ i_q=S_q(T_e,{\mathrm{\&Psi;}}_f)\end{array}\right.,$ S wherein _d, S _qFor about T _eAnd Ψ _fDihydric phenol continuous function formula;

Step 4: with Binary quadratic functions $\left\{\begin{array}{c}{i}_d=S_d(T_e,{\mathrm{\&Psi;}}_f)\\ i_q=S_q(T_e,{\mathrm{\&Psi;}}_f)\end{array}\right.$ Resolve module for Foundation becomes excitation magnetic synchronization motor MTPA control rectangular axis electric current, obtain the d shaft current i that control becomes excitation magnetic synchronization motor _dWith q shaft current i _q

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