CN104283478A - System and method for controlling current of permanent magnet synchronous motor for electric vehicle - Google Patents

Abstract

The invention discloses a system and method for controlling the current of a permanent magnet synchronous motor for an electric vehicle. The system comprises a rotating speed/position detection module used for detecting the rotating speed value omega and the position angle theta of the permanent magnet synchronous motor, a current sensor, a first coordinate transformation module, a second coordinate transformation module, a PI speed ring controller used for conducting PI operation on the motor rotating speed value omega obtained through the rotating speed/position detection module and a given motor rotating speed value omega r to obtain a q-axis current reference value, a current ring prediction control module, a sliding formwork disturbance observation module, a third coordinate transformation module and a space vector pulse width duration modulation module, wherein the space vector pulse width duration modulation module is used for calculating u alpha and u beta to obtain six-path PWM signal output, PWM signals are used for controlling an inverter, and thus three-phase output voltage is obtained to drive the motor to operate. An advanced continuous time generalized prediction control method is adopted for the tracking and controlling of the current of the permanent magnet synchronous motor for the electric vehicle, and the system and method have the advantages of being small in calculated amount, good in control effect and the like.

Description

A kind of Over Electric Motor with PMSM current control system and control method

Technical field

The present invention relates to Over Electric Motor with PMSM (PMSM) curren tracing control method, particularly relate to a kind of PMSM current control system used for electric vehicle with strong tracking and robustness based on generalized predictive control (GPC) and sliding formwork disturbance observer and control method.

Background technology

Along with the aggravation of energy shortage and problem of environmental pollution, electric automobile becomes the main development direction of 21 century auto industry.Efficiency is high, specific power is large, power factor is high, reliability is high and be convenient to safeguard because having for permagnetic synchronous motor, has been considered to have the great potential of competing mutually with asynchronous motor in applications such as electric automobiles.Although PMSM has above-mentioned advantage, but road conditions are complicated when electric automobile runs, operational environment is complicated and changeable, very harsh to the performance requirement of its drive motors system, that adds that motor itself has is non-linear, multivariable, the characteristics such as close coupling, traditional vector control method based on PI can not meet to the high performance requirement of motor.Therefore, the control theory of some advanced persons, as: modified feedback linearization control, sliding formwork controls, adaptive control, the methods such as Reverse Step Control, are applied to this domain variability and achieve many achievements in research, but the dependence of these methods to the parameter of electric machine are strong, for the Parameters variation of motor, load disturbance etc., the method for design disturbance observer is widely used in Electric Machine Control, by estimating disturbed value, and in the Compensation Design of controller, suppress Parameters variation, the motor speed that load disturbance etc. cause, the fluctuation of torque.In recent years, Model Predictive Control as a kind of new control strategy, because it has that control effects is good, strong robustness, to the optimization such as model exactness is less demanding, more and more to be paid attention to.Model Predictive Control utilizes the output of the inputoutput data prediction future time instance of system, then by optimizing the cost function containing output variable and reference locus, obtaining Predictive control law, and being applied in robot, motor, the control fields such as power inverter.Equally, model predictive control method also demonstrates its validity in PMSM controls, but at present for the control of permagnetic synchronous motor, being adopt the PREDICTIVE CONTROL based on system discrete time model mostly, and considering system constraints, realizing on-line optimization by solving quadratic programming problem, although improve PMSM control performance, there is the problem that amount of calculation is large simultaneously, higher to the configuration requirement of control system, limit its application in the contour dynamic non linear system of power drive system.

Summary of the invention

For solving the deficiency that prior art exists, the invention discloses a kind of Over Electric Motor with PMSM current control system and control method, the method is based on the Over Electric Motor with PMSM current control method of continuous-time generalised predictive control and sliding formwork disturbance observer, the fast and stable realizing electric current is followed the tracks of, and is a kind of new method using advanced algorithm to realize current of electric control.

For achieving the above object, concrete scheme of the present invention is as follows:

A kind of Over Electric Motor with PMSM current control method, comprises the following steps:

Step one: utilize rotating speed/position detecting module to obtain rotational speed omega and the angular position theta of permagnetic synchronous motor, angular position theta value be input in the second coordinate transformation module and three-dimensional conversion module, by the rotational speed omega value of motor and given motor speed value ω _rbe input in PI control module, obtain q shaft current reference value through PI computing

Step 2: utilize current sensor to collect the two-phase output current i of permagnetic synchronous motor _aand i _band by output current i _aand i _bbe input in the first coordinate transformation module, first export the null principle of three-phase current sum according to motor, try to achieve third phase current i _c, then utilize motor three-phase current i _a, i _band i _c, through coordinate transform, obtain the current i under two-phase rest frame _αand i _β, the i finally will tried to achieve in the first coordinate transformation module _α, i _βand angular position theta is input to the second coordinate transformation module and obtains i _dand i _q.

Step 3: obtain q shaft current reference value through PI computing by step one given d shaft current reference value and second i that obtain of coordinate transformation module _d, i _qbe input to predictive current control module and obtain output voltage values; By i _d, i _qand permagnetic synchronous motor tachometer value ω is input to sliding formwork disturbance observer module, obtain the estimated value of permagnetic synchronous motor disturbance through sliding formwork disturbance observer module with

Step 4: output voltage values step 3 obtained deducts the estimated value of permagnetic synchronous motor disturbance with obtain control voltage signal u _d, u _q, by u _d, u _qand θ is input to three-dimensional conversion module and obtains u _αand u _β;

Step 5: by u _αand u _βbe input to space vector pulse width modulation module, obtain six road pwm signals and export, and by pwm signal control inverter, the three-phase output voltage obtained by inverter be to drive the operation of permagnetic synchronous motor.

The Mathematical Modeling of described permagnetic synchronous motor under d-q synchronous rotating frame is expressed as:

u _d＝L _ddi _d/dt+R _si _d-n _pωL _qi _q-f _d

(1)

u _q＝L _qdi _q/dt+R _si _q+n _pωL _di _d+n _pωΦ-f _q

In formula, L _dand L _qfor the stator inductance under d-q synchronous rotating frame, i _d, i _q, u _d, u _qbe respectively the stator current under d-q coordinate system and voltage, R _sfor stator resistance, n _pfor number of pole-pairs, ω is rotor mechanical angular speed, and Φ is the magnetic linkage that permanent magnet produces, f _d, f _qfor the disturbance quantity caused by Parameters variation.

The Mathematical Modeling of described permagnetic synchronous motor is expressed as non linear system, writ state variable x=[L _di _dl _qi _q] ^t, input variable u=[u _du _q] ^t, disturbance quantity d=[f _df _q] ^t, output variable y=h (x)=[i _di _q] ^t, obtain non linear system:

$\left\{\begin{array}{c}\stackrel{\·}{x}=f\left(x\right)+g_1\left(x\right)u+d\\ y=h\left(x\right)=g_2\left(x\right)x\end{array}\right.---\left(2\right)$

Wherein, $g_1\left(x\right)=\left[\begin{array}{cc}1& 0\\ 0& 1\end{array}\right],g_2\left(x\right)=\left[\begin{array}{cc}\frac{1}{L_d}& 0\\ 0& \frac{1}{L_q}\end{array}\right],f\left(x\right)=\left[\begin{array}{c}-R_s{i}_d+n_p{\mathrm{\ωL}}_q{i}_q\\ -R_s{i}_q-n_p{\mathrm{\ωL}}_d{i}_d-n_p\mathrm{\ω\Φ}\end{array}\right]$

Definition cost function $J=\frac{1}{2}{\∫}_0^T{(\hat{y}(t+\mathrm{\τ})-y_r(t+\mathrm{\τ}))}^T(\hat{y}(t+\mathrm{\τ})-y_r(t+\mathrm{\τ}))\mathrm{d\τ},$ Wherein, T is prediction time domain, y _r(t+ τ) is respectively prediction output current and the reference current of system.

In described step 3, for the nominal system not considering disturbance d, system exports i _d, i _qbe ρ=1 to the Relative order of input, get the control rank r=0 of system input, and will to export ρ differentiate is arrived to 0 of the time, prediction is exported in t by Taylor series expansion, until ρ+r time:

$\hat{y}(t+\mathrm{\τ})=\left[\begin{array}{cccc}1& 0& \mathrm{\τ}& 0\\ 0& 1& 0& \mathrm{\τ}\end{array}\right]\left[\begin{array}{c}\hat{y}\left(t\right)\\ \stackrel{\·}{\hat{y}}\left(t\right)\end{array}\right]---\left(3\right)$

Then above formula (3) is expressed as form, in like manner, with reference to export obtained by Taylor series expansion $y_r(t+\mathrm{\τ})=\mathrm{\Γ}\left(\mathrm{\τ}\right){\stackrel{\‾}{Y}}_r\left(t\right),$ Wherein, ${\stackrel{\‾}{Y}}_r\left(t\right)={\left[\begin{array}{cc}{y}_r{\left(t\right)}^T& {\stackrel{\·}{y}}_r{\left(t\right)}^T\end{array}\right]}^T;$

Order $\stackrel{\‾}{\mathrm{\Γ}}\left(T\right)={\∫}_0^T{\mathrm{\Γ}}^T\left(\mathrm{\τ}\right)\mathrm{\Γ}\left(\mathrm{\τ}\right)\mathrm{d\τ},$ Then cost function can be expressed as $J=\frac{1}{2}{[\stackrel{\‾}{Y}\left(t\right)-{\stackrel{\‾}{Y}}_r\left(t\right)]}^T\stackrel{\‾}{\mathrm{\Γ}}\left(T\right)[\stackrel{\‾}{Y}\left(t\right)-{\stackrel{\‾}{Y}}_r\left(t\right)]$

For making cost function reach minimum, obtain the predictive current control rule of nominal system thus:

$u=-G^{-1}\left(x\right)({\mathrm{KM}}_{\mathrm{\ρ}}+L_{f}h\left(x\right)-{\stackrel{\·}{y}}_r)---\left(4\right)$

Wherein,

$G\left(x\right)=\left[\begin{array}{cc}{L}_{g11}h\left(x\right)& L_{g12}h\left(x\right)\end{array}\right]=\left[\begin{array}{cc}\frac{1}{L_d}& 0\\ 0& \frac{1}{L_q}\end{array}\right],M_{\mathrm{\ρ}}=[h\left(x\right)-y_r\left(t\right)]=\left[\begin{array}{c}{i}_d-i_d^{*}\\ i_q-i_q^{*}\end{array}\right],$

$L_{f}h\left(x\right)=\left[\begin{array}{cc}\frac{1}{L_d}& 0\\ 0& \frac{1}{L_q}\end{array}\right]f\left(x\right),$ for reference current, g ₁₁and g ₁₂for g ₁the column vector of (x), K ∈ R ^{2 × 2}be by front two row composition matrix, and $\stackrel{\‾}{\mathrm{\Γ}}\left(T\right)=\left[\begin{array}{cc}{\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{\ρ\ρ}}& {\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{\ρr}}\\ {\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{\ρr}}^T& {\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{rr}}\end{array}\right],$ Wherein, ${\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{\ρ\ρ}}\∈R^{2\×2},{\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{\ρr}}\∈R^{2\×2},{\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{rr}}\∈R^{2\×2}.$

In described step 3, when considering actual disturbance quantity d, the generalized predictive control rule of system is expressed as $u=-G^{-1}\left(x\right)({\mathrm{KM}}_{\mathrm{\ρ}}+L_{f}h\left(x\right)-{\stackrel{\·}{y}}_r+G_1\·\hat{d})---\left(5\right)$

Wherein, $G_1=\frac{\∂h\left(x\right)}{\∂x}=\left[\begin{array}{cc}\frac{1}{L_d}& 0\\ 0& \frac{1}{L_d}\end{array}\right],$ for the measured value of compound disturbance.

The detailed process of asking for of described compound disturbance observation value is:

First sliding formwork disturbance observer is constructed $\left\{\begin{array}{c}s=x-z\\ \stackrel{\·}{z}=g_{1}u-v\\ \hat{d}=-(v+f)\end{array}\right.---\left(6\right)$

In formula, s=[s ₁s ₂] ^t, namely i=1,2

Obtained by formula (6) $\stackrel{\·}{s}=\stackrel{\·}{x}-\stackrel{\·}{z}=f+g_{1}u+d-g_{1}u+v=f+d+v---\left(7\right)$

Get the Lyapunov function of sliding formwork disturbance observer make ξ=f+d=[ξ ₁ξ ₂] ^t, then definition if choose then ${\stackrel{\·}{V}}_i\≤0,$ Thus so sliding formwork disturbance observation value

A kind of Over Electric Motor with PMSM current control system, comprising:

Rotating speed/position detecting module, for detecting tachometer value ω and the angular position theta of permagnetic synchronous motor;

Current sensor, for gathering permagnetic synchronous motor two-phase output current i _aand i _band be input to the first coordinate transformation module;

First coordinate transformation module, for by two-phase output current i _aand i _bthe current i under two-phase rest frame is obtained through coordinate transform _αand i _β;

Second coordinate transformation module, for by i _α, i _βand angular position theta obtains i through the static coordinate transform rotated to two-phase of two-phase _dand i _q;

PI speed ring controller, for the motor speed value ω that rotating speed/position detecting module obtained and given motor speed value ω _rq shaft current reference value is obtained through PI computing

Electric current loop PREDICTIVE CONTROL module, for by q shaft current reference value given d shaft current reference value and second i that obtain of coordinate transformation module _d, i _qcarry out prediction computing and obtain output voltage values;

Sliding formwork disturbance observation module, for just i _d, i _qand motor speed value ω is as input, obtain the estimated value of permagnetic synchronous motor disturbance through observer with

Three-dimensional conversion module, the output voltage values for electric current loop PREDICTIVE CONTROL module being obtained deducts the estimated value of disturbance respectively with the control voltage signal u obtained _d, u _q, and the coordinate transform that θ rotates to two-phase static through two-phase obtains u _αand u _β;

Space vector pulse width modulation module, for by u _αand u _βcalculate six road pwm signals to export, and by pwm signal control inverter, obtain the operation that three-phase output voltage carrys out drive motors thus.

Beneficial effect of the present invention:

The present invention adopts the generalized forecast control method based on sliding formwork disturbance observer to substitute the PI control method of electric current loop in conventional vector control, the controller regulating parameter obtained is few, control more easily to regulate than PI, and the present invention adopts the forecast Control Algorithm based on continuous time model, with consider retrain based on discrete model forecast Control Algorithm compared with, there is amount of calculation little, low to the configuration requirement of controller, the more easily advantage such as realization, the introducing of sliding formwork disturbance observer adds the performance of noiseproof of system, when system parameter variations, the disturbed value of the effective estimating system of energy, and for the Front feedback control of controller, system is made to have stronger robust performance.

1, advanced continuous-time generalised predictive control method is adopted to be used for, in the current follow-up control of Over Electric Motor with PMSM, having Controller gain variations simple, the advantages such as amount of calculation is little, and control effects is good.

2, for adapt to electric automobile run in the parameter perturbation that brings to electric machine control system of severe working condition, estimate disturbance quantity in conjunction with sliding formwork disturbance observer method, and for the compensatory control of electric current, make system have stronger robust performance.

Accompanying drawing explanation

Accompanying drawing explanation

Fig. 1 the present invention carry the overall structure block diagram of control method;

Fig. 2 a load torque and the parameter of electric machine constant time d shaft current aircraft pursuit course;

Fig. 2 b load torque and the parameter of electric machine constant time q shaft current aircraft pursuit course;

Fig. 2 c load torque and the parameter of electric machine constant time dq shaft current tracking error curve;

D shaft current aircraft pursuit course during the change of Fig. 3 a load torque;

Q shaft current aircraft pursuit course during the change of Fig. 3 b load torque;

Dq shaft current tracking error curve during the change of Fig. 3 c load torque;

Phase current curve during the change of Fig. 3 d load torque;

D shaft current aircraft pursuit course during the change of Fig. 4 a parameter of electric machine;

Q shaft current aircraft pursuit course during the change of Fig. 4 b parameter of electric machine;

Dq shaft current tracking error curve figure during the change of Fig. 4 c parameter of electric machine;

In figure, 1, current sensor, the 2, first coordinate transformation module, the 3, second coordinate transformation module, 4, rotating speed/position detecting module, 5, PI speed ring controller, 6, electric current loop PREDICTIVE CONTROL module, 7, sliding formwork disturbance observation module, 8, three-dimensional conversion module, 9, space vector pulse width modulation module, 10, inverter, 11, permagnetic synchronous motor.

Embodiment:

Below in conjunction with accompanying drawing, the present invention is described in detail:

As shown in Figure 1, a kind of Over Electric Motor with PMSM current control method, comprises the following steps:

1) in PMSM running, rotational speed omega and the angular position theta of permagnetic synchronous motor is obtained through rotating speed/position detecting module 4, and θ value is input in the second coordinate transformation module 3 and three-dimensional conversion module 8, by the permagnetic synchronous motor tachometer value ω that obtains and given motor speed value ω _rbe input in PI speed ring controller 5, obtain q shaft current reference value through PI computing

2) the motor two-phase output current i that will collect of current sensor 1 _aand i _bbe input to for first coordinate transformation module 2 of three phase static to the static coordinate transform of two-phase, first equal zero according to three-phase current sum, try to achieve third phase current i _c, and through coordinate transform, obtain the current i under two-phase rest frame _αand i _β, then i _α, i _βand angular position theta is input to the second coordinate transformation module 3, carries out the static coordinate transform rotated to two-phase of two-phase and obtain i _dand i _q.

3) q shaft current reference value PI speed ring controller 5 obtained given d shaft current reference value and second i that obtain of coordinate transformation module 3 _d, i _qbe input to predictive current control module 6, through the predictive current control device introduced, obtain output voltage values below.By i _d, i _qand motor speed value ω is input to sliding formwork disturbance observer module 7, obtains the estimated value of motor disturbance through observer with

4) by the 3rd) the control voltage signal u that obtains of the output voltage values that obtains in the step disturbed value that deducts estimation _d, u _q, and θ is input to the three-dimensional conversion module 8 rotating to the static coordinate transform of two-phase for two-phase and obtains u _αand u _β.

5) by u _αand u _βbe input to space vector pulse width modulation module 9 i.e. SVPWM module, the six road pwm signals obtaining controller export, and by pwm signal control inverter 10, obtain the operation that three-phase output voltage carrys out drive motors thus.

In test, der Geschwindigkeitkreis adopts PI to control, and electric current loop adopts generalized forecast control method, and adopts sliding formwork disturbance observer to estimate the compensatory control of disturbed value for electric current loop.The present invention adopts i at electric current loop _dthe control method of=0, result of the test as in Figure 2-4.

Fig. 2 is given motor speed 800rmp, load torque is 0.5Nm, the parameter of electric machine and load constant when, motor dq shaft current aircraft pursuit course, Fig. 2 a is d shaft current aircraft pursuit course, and Fig. 2 b is q shaft current aircraft pursuit course, and Fig. 2 c is dq shaft current tracking error curve, as seen from the figure, motor output current can be good at tracing preset dq shaft current curve.

Fig. 3 is given motor speed 800rmp, load torque is 0.5Nm, when t=1s, current curve when load torque becomes 1Nm from 0.5Nm, Fig. 3 a is d shaft current aircraft pursuit course, Fig. 3 b is q shaft current aircraft pursuit course, Fig. 3 c is dq shaft current tracking error curve, and phase current curve when Fig. 3 is load torque change, goes out from the experimental results, during load torque change, dq shaft current has good tracking performance.

In order to verify that current control method that the present invention proposes not to mate the robust performance of Time Controller at motor actual parameter and controller parameter, the parameter of electric machine set is become: R in controller _st=0.5*R _s, L _dt=0.75*L _d, L _qt=0.75*L _q, Φ _t=1.2* Φ, Fig. 4 is the current tracking curve after corresponding parameter of electric machine change, wherein, Fig. 4 a is d shaft current aircraft pursuit course, and Fig. 4 b is q shaft current aircraft pursuit course, Fig. 4 c is dq shaft current tracking error curve, as seen from the figure, when after the parameter of electric machine change in controller, electric current still can tracing preset current curve fast, experimental result shows, the curren tracing control method in the present invention has good robust control performance.

Predictive current control module 6 and sliding formwork disturbance observer module 7 as follows:

First adopt continuous time model generalized forecast control method, according to system continuous time model, the system in finite time-domain exports to utilize Taylor series expansion to predict, is tried to achieve the generalized predictive control rate of system by the cost function of definition.

By rotor field-oriented theory, the Mathematical Modeling of PMSM under d-q synchronous rotating frame can be expressed as

u _d＝L _ddi _d/dt+R _si _d-n _pωL _qi _q-f _d

(1)

u _q＝L _qdi _q/dt+R _si _q+n _pωL _di _d+n _pωΦ-f _q

In formula, L _dand L _qfor the stator inductance under d-q synchronous rotating frame, i _d, i _q, u _d, u _qbe respectively the stator current under d-q coordinate system and voltage, R _sfor stator resistance, n _pfor number of pole-pairs, ω is rotor mechanical angular speed, and Φ is the magnetic linkage that permanent magnet produces, f _d, f _qfor the disturbance quantity caused by Parameters variation.The object of order invention asks the current tracing controller of control system for permanent-magnet synchronous motor, makes x=[L _di _dl _qi _q] ^t, u=[u _du _q] ^t, d=[f _df _q] ^t, y=h (x)=[i _di _q] ^t, the form that the Mathematical Modeling of permagnetic synchronous motor is expressed as non linear system is obtained

$\left\{\begin{array}{c}\stackrel{\·}{x}=f\left(x\right)+g_1\left(x\right)u+d\\ y=h\left(x\right)=g_2\left(x\right)x\end{array}\right.---\left(2\right)$

Wherein, $g_1\left(x\right)=\left[\begin{array}{cc}1& 0\\ 0& 1\end{array}\right],g_2\left(x\right)=\left[\begin{array}{cc}\frac{1}{L_d}& 0\\ 0& \frac{1}{L_q}\end{array}\right],f\left(x\right)=\left[\begin{array}{c}-R_s{i}_d+n_p{\mathrm{\ωL}}_q{i}_q\\ -R_s{i}_q-n_p{\mathrm{\ωL}}_d{i}_d-n_p\mathrm{\ω\Φ}\end{array}\right]$

Definition cost function $J=\frac{1}{2}{\∫}_0^T{(\hat{y}(t+\mathrm{\τ})-y_r(t+\mathrm{\τ}))}^T(\hat{y}(t+\mathrm{\τ})-y_r(t+\mathrm{\τ}))\mathrm{d\τ},$ Wherein, T is prediction time domain, y _r(t+ τ) is respectively prediction output current and the reference current of system.

For the nominal system not considering disturbance d, system exports i _d, i _qbe ρ=1 to the Relative order of input, get the control rank r=0 of system input, and will to export ρ differentiate is arrived to 0 of the time, prediction is exported in t by Taylor series expansion, until ρ+r time

$\hat{y}(t+\mathrm{\τ})=\left[\begin{array}{cccc}1& 0& \mathrm{\τ}& 0\\ 0& 1& 0& \mathrm{\τ}\end{array}\right]\left[\begin{array}{c}\hat{y}\left(t\right)\\ \stackrel{\·}{\hat{y}}\left(t\right)\end{array}\right]---\left(3\right)$

Then above formula is expressed as form, in like manner, with reference to export obtained by Taylor series expansion $y_r(t+\mathrm{\τ})=\mathrm{\Γ}\left(\mathrm{\τ}\right){\stackrel{\‾}{Y}}_r\left(t\right),$ Wherein, ${\stackrel{\‾}{Y}}_r\left(t\right)={\left[\begin{array}{cc}{y}_r{\left(t\right)}^T& {\stackrel{\·}{y}}_r{\left(t\right)}^T\end{array}\right]}^T$

Order $\stackrel{\‾}{\mathrm{\Γ}}\left(T\right)={\∫}_0^T{\mathrm{\Γ}}^T\left(\mathrm{\τ}\right)\mathrm{\Γ}\left(\mathrm{\τ}\right)\mathrm{d\τ},$ Then cost function can be expressed as again $J=\frac{1}{2}{[\stackrel{\‾}{Y}\left(t\right)-{\stackrel{\‾}{Y}}_r\left(t\right)]}^T\stackrel{\‾}{\mathrm{\Γ}}\left(T\right)[\stackrel{\‾}{Y}\left(t\right)-{\stackrel{\‾}{Y}}_r\left(t\right)]$

For making cost function reach minimum, the predictive current control rule of nominal system can be obtained thus:

$u=-G^{-1}\left(x\right)({\mathrm{KM}}_{\mathrm{\ρ}}+L_{f}h\left(x\right)-{\stackrel{\·}{y}}_r)---\left(4\right)$

Wherein,

$G\left(x\right)=\left[\begin{array}{cc}{L}_{g11}h\left(x\right)& L_{g12}h\left(x\right)\end{array}\right]=\left[\begin{array}{cc}\frac{1}{L_d}& 0\\ 0& \frac{1}{L_q}\end{array}\right],M_{\mathrm{\ρ}}=[h\left(x\right)-y_r\left(t\right)]=\left[\begin{array}{c}{i}_d-i_d^{*}\\ i_q-i_q^{*}\end{array}\right],$

$L_{f}h\left(x\right)=\left[\begin{array}{cc}\frac{1}{L_d}& 0\\ 0& \frac{1}{L_q}\end{array}\right]f\left(x\right),$ for reference current, g ₁₁and g ₁₂for g ₁the column vector of (x), K ∈ R ^{2 × 2}be by front two row composition matrix, and $\stackrel{\‾}{\mathrm{\Γ}}\left(T\right)=\left[\begin{array}{cc}{\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{\ρ\ρ}}& {\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{\ρr}}\\ {\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{\ρr}}^T& {\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{rr}}\end{array}\right],$ Wherein, ${\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{\ρ\ρ}}\∈R^{2\×2},{\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{\ρr}}\∈R^{2\×2},{\stackrel{\‾}{\mathrm{\Γ}}}_{\mathrm{rr}}\∈R^{2\×2}.$

Formula (4) adopts the Current Control of generalized predictive control theory to restrain under having tried to achieve and not considered disturbance situation, but in the Motor for Electric Automobile drive system of reality, the disturbance of system is inevitable, as operational environment, to change the parameter of electric machine change modeling caused inaccurate etc., when considering actual disturbance d, the generalized predictive control rule of system is expressed as:

$u=-G^{-1}\left(x\right)({\mathrm{KM}}_{\mathrm{\ρ}}+L_{f}h\left(x\right)-{\stackrel{\·}{y}}_r+G_1\·\hat{d})---\left(5\right)$

Wherein, $G_1=\frac{\∂h\left(x\right)}{\∂x}=\left[\begin{array}{cc}\frac{1}{L_d}& 0\\ 0& \frac{1}{L_d}\end{array}\right],$ for compound disturbance observation value.

In formula (5), there is unknown disturbance quantity, in order to try to achieve control law, first need obtain the value of disturbance quantity, for this reason, the present invention devises a kind of novel disturbance observer based on sliding-mode method for the disturbance variable in estimating system.

First sliding formwork disturbance observer is constructed $\left\{\begin{array}{c}s=x-z\\ \stackrel{\·}{z}=g_{1}u-v\\ \hat{d}=-(v+f)\end{array}\right.---\left(6\right)$

In formula, s=[s ₁s ₂] ^t, namely i=1,2

Obtained by formula (6) $\stackrel{\·}{s}=\stackrel{\·}{x}-\stackrel{\·}{z}=f+g_{1}u+d-g_{1}u+v=f+d+v---\left(7\right)$

Get the Lyapunov function of sliding formwork disturbance observer make ξ=f+d=[ξ ₁ξ ₂] ^t, then definition if choose then thus $\stackrel{\&CenterDot;}{V}<0.$

Sliding formwork disturbance observer according to the provable structure of Liapunov stability law is asymptotically stable, sliding formwork disturbance observation value the robustness of system is improve by the design of sliding formwork disturbance observer.Although above-mentioned research demonstrates the stability of sliding formwork disturbance observer, do not prove the stability of whole hybrid system under generalized predictive control rule and the effect of sliding formwork disturbance observer.Prove the stability of hybrid system under generalized predictive control rule (5) effect below.

Obtained by formula (2) make e=y (t)-y _r, and then can obtain

$\stackrel{\&CenterDot;}{e}=\stackrel{\&CenterDot;}{y}\left(t\right)-{\stackrel{\&CenterDot;}{y}}_r=-{\mathrm{KM}}_{\mathrm{\&rho;}}+G_1(d-\hat{d})=-\mathrm{Ke}+G_1(d-\hat{d})$

The error equation of closed-loop system can be expressed as wherein, A=-K, B=G ₁, the observation error of definition sliding formwork disturbance observer is e _d=s=x-z, is expressed as the error vector of closed-loop system $E={\left[\begin{array}{cc}{e}^T& e_d^T\end{array}\right]}^T$ The Lyapunov function getting system is $V_1=\frac{1}{2}{E}^T\stackrel{\&OverBar;}{P}E,\stackrel{\&OverBar;}{P}=\left[\begin{array}{cc}P& 0\\ 0& I_d\end{array}\right],$ Wherein P=diag{P ₁p ₂, P _ifor symmetric positive definite matrix and meet i=1,2, and then can release therefore hybrid system is asymptotically stable.Finally build the test platform of control system, demonstrated the validity of institute of the present invention extracting method by test.

Claims (7)

1. an Over Electric Motor with PMSM current control method, is characterized in that, comprises the following steps:

Step one: utilize rotating speed/position detecting module to obtain rotational speed omega and the angular position theta of permagnetic synchronous motor, angular position theta value be input in the second coordinate transformation module and three-dimensional conversion module, by the rotational speed omega value of motor and given motor speed value ω _rbe input in PI control module, obtain q shaft current reference value through PI computing

Step 2: utilize current sensor to collect the two-phase output current i of permagnetic synchronous motor _aand i _band by output current i _aand i _bbe input in the first coordinate transformation module, first export the null principle of three-phase current sum according to motor, try to achieve third phase current i _c, then utilize motor three-phase current i _a, i _band i _c, through coordinate transform, obtain the current i under two-phase rest frame _αand i _β, the i finally will tried to achieve in the first coordinate transformation module _α, i _βand angular position theta is input to the second coordinate transformation module and obtains i _dand i _q.Step 3: obtain q shaft current reference value through PI computing by step one given d shaft current reference value and second i that obtain of coordinate transformation module _d, i _qbe input to predictive current control module and obtain output voltage values, by i _d, i _qand permagnetic synchronous motor tachometer value ω is input to sliding formwork disturbance observer module, obtain the estimated value of permagnetic synchronous motor disturbance through sliding formwork disturbance observer module with

Step 4: output voltage values step 3 obtained deducts the estimated value of permagnetic synchronous motor disturbance with obtain control voltage signal u _d, u _q, by u _d, u _qand θ is input to three-dimensional conversion module and obtains u _αand u _β;

Step 5: by u _αand u _βbe input to space vector pulse width modulation module, obtain six road pwm signals and export, and by pwm signal control inverter, the three-phase output voltage obtained by inverter be to drive the operation of permagnetic synchronous motor.

2. a kind of Over Electric Motor with PMSM current control method as claimed in claim 1, is characterized in that, the Mathematical Modeling of described permagnetic synchronous motor under d-q synchronous rotating frame is expressed as:

$\begin{array}{c}{u}_d=L_d{\mathrm{di}}_d/\mathrm{dt}+R_s{i}_d-n_p\mathrm{\&omega;}{L}_q{i}_q-f_d\\ u_q=L_q{\mathrm{di}}_q/\mathrm{dt}+R_s{i}_q+n_p\mathrm{\&omega;}{L}_d{i}_d+n_p\mathrm{\&omega;\&Phi;}-f_q\end{array}---\left(1\right)$

In formula, L _dand L _qfor the stator inductance under d-q synchronous rotating frame, i _d, i _q, u _d, u _qbe respectively the stator current under d-q coordinate system and voltage, R _sfor stator resistance, n _pfor number of pole-pairs, ω is rotor mechanical angular speed, and Φ is the magnetic linkage that permanent magnet produces, f _d, f _qfor the disturbance quantity caused by Parameters variation.

3. a kind of Over Electric Motor with PMSM current control method as claimed in claim 2, it is characterized in that, the Mathematical Modeling of described permagnetic synchronous motor is expressed as non linear system, makes x=[L _di _dl _qi _q] ^t, u=[u _du _q] ^t, d=[f _df _q] ^t, y=h (x)=[i _di _q] ^t, obtain non linear system:

$\left\{\begin{array}{c}\stackrel{\&CenterDot;}{x}=f\left(x\right)+g_1\left(x\right)u+d\\ y=h\left(x\right)=g_2\left(x\right)x\end{array}\right.---\left(2\right).$

4. a kind of Over Electric Motor with PMSM current control method as claimed in claim 1, is characterized in that, in described step 3, for the nominal system not considering disturbance d, system exports i _d, i _qbe ρ=1 to the Relative order of input, get the control rank r=0 of system input, and will to export ρ differentiate is arrived to 0 of the time, prediction is exported in t by Taylor series expansion, until ρ+r time

$\hat{y}(t+\mathrm{\&tau;})=\left[\begin{array}{cccc}1& 0& \mathrm{\&tau;}& 0\\ 0& 1& 0& \mathrm{\&tau;}\end{array}\right]\left[\begin{array}{c}\hat{y}\left(t\right)\\ \stackrel{\stackrel{\&CenterDot;}{^}}{y}\left(t\right)\end{array}\right]---\left(3\right)$

Then above formula (3) is expressed as form, in like manner, with reference to export obtained by Taylor series expansion $y_r(t+\mathrm{\&tau;})=\mathrm{\&Gamma;}\left(\mathrm{\&tau;}\right){\stackrel{\&OverBar;}{Y}}_r\left(t\right),$ Wherein, ${\stackrel{\&OverBar;}{Y}}_r\left(t\right)={\left[\begin{array}{cc}{y}_r{\left(t\right)}^T& {\stackrel{\&CenterDot;}{y}}_r{\left(t\right)}^T\end{array}\right]}^T$

Order $\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}\left(T\right)={\&Integral;}_0^T{\mathrm{\&Gamma;}}^T\left(\mathrm{\&tau;}\right)\mathrm{\&Gamma;}\left(\mathrm{\&tau;}\right)\mathrm{d\&tau;},$ Then cost function is expressed as $J=\frac{1}{2}{[\stackrel{\&OverBar;}{Y}\left(t\right)-{\stackrel{\&OverBar;}{Y}}_r\left(t\right)]}^T\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}\left(T\right)[\stackrel{\&OverBar;}{Y}\left(t\right)-{\stackrel{\&OverBar;}{Y}}_r\left(t\right)]$

For making cost function reach minimum, obtain the predictive current control rule of nominal system thus:

$u=-G^{-1}\left(x\right)({\mathrm{KM}}_{\mathrm{\&rho;}}+L_{f}h\left(x\right)-{\stackrel{\&CenterDot;}{y}}_r)---\left(4\right)$

Wherein,

$G\left(x\right)=\left[\begin{array}{cc}{L}_{g11}h\left(x\right)& L_{g12}h\left(x\right)\end{array}\right]=\left[\begin{array}{cc}\frac{1}{L_d}& 0\\ 0& \frac{1}{L_q}\end{array}\right],M_{\mathrm{\&rho;}}=[h\left(x\right)-y_r\left(t\right)]=\left[\begin{array}{cc}{i}_d& i_d^{*}\\ i_q& i_q^{*}\end{array}\right],$

$L_{f}h\left(x\right)=\left[\begin{array}{cc}\frac{1}{L_d}& 0\\ 0& \frac{1}{L_q}\end{array}\right]f\left(x\right),$ for reference current, g ₁₁and g ₁₂for g ₁the column vector of (x), K ∈ R ^{2 × 2}be by front two row composition matrix, and $\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}\left(T\right)=\left[\begin{array}{cc}{\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}}_{\mathrm{\&rho;\&rho;}}& {\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}}_{\mathrm{\&rho;r}}\\ {\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}}_{\mathrm{\&rho;r}}^T& {\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}}_{\mathrm{rr}}\end{array}\right],$ Wherein, ${\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}}_{\mathrm{\&rho;\&rho;}}\&Element;R^{2\&times;2},{\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}}_{\mathrm{\&rho;r}}\&Element;R^{2\&times;2},{\stackrel{\&OverBar;}{\mathrm{\&Gamma;}}}_{\mathrm{rr}}\&Element;R^{2\&times;2}.$

5. a kind of Over Electric Motor with PMSM current control method as claimed in claim 4, is characterized in that, in described step 3, when considering actual disturbance d, the generalized predictive control rule of system is expressed as $u=-G^{-1}\left(x\right)({\mathrm{KM}}_{\mathrm{\&rho;}}+L_{f}h\left(x\right)-{\stackrel{\&CenterDot;}{y}}_r+G_1\&CenterDot;\hat{d})---\left(5\right)$

Wherein, $G_1=\frac{\&PartialD;h\left(x\right)}{\&PartialD;x}=\left[\begin{array}{cc}\frac{1}{L_d}& 0\\ 0& \frac{1}{L_q}\end{array}\right],$ for compound disturbance observation value.

6. a kind of Over Electric Motor with PMSM current control method as claimed in claim 5, is characterized in that, the detailed process of asking for of described compound disturbance observation value is:

First sliding formwork disturbance observer is constructed $\left\{\begin{array}{c}s=x-z\\ \stackrel{\&CenterDot;}{z}=g_{1}u-v\\ \hat{d}=-(v+f)\end{array}\right.---\left(6\right)$

In formula, namely i=1,2 are obtained by formula (6) $\stackrel{\&CenterDot;}{s}=\stackrel{\&CenterDot;}{x}-\stackrel{\&CenterDot;}{z}=f+g_{1}u+d-g_{1}u+v=f+d+v---\left(7\right)$

Get the Lyapunov function of sliding formwork disturbance observer make ξ=f+d=[ξ ₁ξ ₂] ^t, then definition if choose then thus so sliding formwork disturbance observation value

7. the control system of a kind of Over Electric Motor with PMSM current control method as claimed in claim 1, is characterized in that, comprising:

Rotating speed/position detecting module, for detecting tachometer value ω and the angular position theta of permagnetic synchronous motor;

Current sensor, for gathering permagnetic synchronous motor two-phase output current i _aand i _band be input to the first coordinate transformation module;

First coordinate transformation module, for by two-phase output current i _aand i _bthe current i under two-phase rest frame is obtained through coordinate transform _αand i _β;

Second coordinate transformation module, for by i _α, i _βand angular position theta obtains i through the static coordinate transform rotated to two-phase of two-phase _dand i _q;

PI speed ring controller, for the motor speed value ω that rotating speed/position detecting module obtained and given motor speed value ω _rq shaft current reference value is obtained through PI computing

Electric current loop PREDICTIVE CONTROL module, for by q shaft current reference value given d shaft current reference value and second i that obtain of coordinate transformation module _d, i _qcarry out prediction computing and obtain output voltage values;

Sliding formwork disturbance observation module, for just i _d, i _qand motor speed value ω is as input, obtain the estimated value of permagnetic synchronous motor disturbance through observer with

Three-dimensional conversion module, the output voltage values for electric current loop PREDICTIVE CONTROL module being obtained deducts the estimated value of disturbance respectively with obtain control voltage signal u _d, u _q, by u _d, u _qand the coordinate transform that θ rotates to two-phase static through two-phase obtains u _αand u _β;

Space vector pulse width modulation module, for by u _αand u _βcalculate six road pwm signals to export, and by pwm signal control inverter, obtain the operation that three-phase output voltage carrys out drive motors thus.