CN102969968A - Permanent magnet synchronous motor control method - Google Patents

Abstract

The invention discloses a permanent magnet synchronous motor control method in which a vector control system is used. The vector control system comprises an outer speed ring and an inner current ring, and a PI (proportional-integral) controller of a rotating speed ring is replaced with a two-DOF (degree of freedom) higher-order nonsingular terminal sliding mode controller; the input of the two-DOF higher-order nonsingular terminal sliding mode controller is the difference between the given rotating speed w* of a motor and the actual feedback rotating speed w* of the motor; the error between the given rotating speed and the feedback rotating speed is judged, when the error of the rotating speed is less than Xi, an output exciting current iq* is calculated by a simple higher-order nonsingular terminal sliding mode controller; when the error of the rotating speed is greater than Xi, the output of the two-DOF higher-order nonsingular terminal sliding mode controller is an output iq* controlled by a higher-order nonsingular terminal sliding mode and the sum of the output and compensation gain of the higher-order nonsingular terminal sliding mode; and the size of Xi can be set according to actual situations and needs. According to the method, the system control accuracy is improved and the rapid convergence of the rotating speed of the motor is realized; and the method has strong robustness on load disturbances.

Description

A kind of method for controlling permanent magnet synchronous motor

Technical field

The present invention relates to a kind of method for controlling permanent magnet synchronous motor.

Background technology

Permagnetic synchronous motor (Permanent Magnet Synchronous Motor is abbreviated as PMSM) has the advantages such as low inertia, fast-response, high power density, low-loss, high efficiency.And along with increasing substantially of permanent magnetic material performance, its application in the industrial production automation field will be more and more extensive.But because permagnetic synchronous motor is the multivariable system of a high-order, non-linear, close coupling, also exist the uncertainties such as Parameter Perturbation, load disturbance simultaneously, therefore will carry out difficulty of high performance control ratio to it.Have much for the control method of PMSM at present to be suggested, such as adaptive control, fuzzy control, neural net, Active Disturbance Rejection Control etc.But these are applied in because the algorithm more complicated seldom has in the actual engineering.

Sliding moding structure has good consistency because of it to system parameters uncertainty and external disturbance, begun to be widely used in the electric machine speed regulation field, Sliding mode variable structure control has strong robustness, realizes simple advantage, when the parameter of electric machine changes and disturbance occurs, still the performance of satisfaction guaranted, thereby be subject to the attention of increasing Chinese scholars.But because the discontinuity of its control action is easy to make system to produce and buffets, greatly affected the application in the working control.The high frequency switching controls can cause chattering phenomenon under the effect of disturbance and model parameter perturbation.And the proportional relation of amplitude of the amplitude of buffeting and disturbance and model parameter perturbation.In electric machine control system, buffet and can produce pulsation thrust, affect stationarity and the positioning accuracy of system, increase energy loss.The nonsingular terminal sliding mode that proposed in recent years can make system mode arrive balance point in finite time, and steady-state tracking precision is high, buffets but still exist.Use saturation function and replace switch function, emulation shows that it has weakened buffeting to a certain extent, but has also weakened the robustness of system simultaneously.Using observer observation load disturbance is also compensated, the method is by reducing nonlinear terms, can reduce preferably to buffet, but increase the complexity of system because having increased observer, and the existence of system chatter affects accuracy of observation, the actual effect of improving that reaches desirable of being difficult to.

Summary of the invention

The object of the present invention is to provide a kind of method for controlling permanent magnet synchronous motor, to improve robustness and the dynamic responding speed of electric machine control system.

The object of the present invention is achieved like this, a kind of method for controlling permanent magnet synchronous motor, adopt vector control system, vector control system comprises speed outer shroud and current inner loop two parts, and the PI controller of der Geschwindigkeitkreis adopts the nonsingular terminal sliding mode controller of two degrees of freedom high-order to replace; The given rotating speed w that is input as motor of the nonsingular terminal sliding mode controller of two degrees of freedom high-order ^*Poor with the actual feedback rotating speed w of motor judged the error size of given rotating speed and feedback rotating speed, when speed error during less than ξ, and the exciting current i of output _q ^*To calculate by the nonsingular terminal control unit of simple High-Order Sliding Mode to realize; When speed error during greater than ξ the nonsingular terminal sliding mode control of two degrees of freedom high-order be output as the output i of the nonsingular terminal sliding mode control of high-order _q ^*Output and compensating gain sum for the nonsingular terminal sliding mode of high-order; Wherein the large I of ξ is according to actual conditions and requirements set.

The present invention has following beneficial effect:

1, the present invention replaces the PI controller in the der Geschwindigkeitkreis by adopting with the nonsingular terminal control of two degrees of freedom High-Order Sliding Mode, switching item in traditional sliding-mode control is added on the derivative of terminal sliding mode control method, therefore, effectively reduce the buffeting problem of sliding moding structure in system's control procedure, thereby also improved system's control precision, so that rotating speed can be able to effectively be converged near the balance point.

2, the present invention proposes the permagnetic synchronous motor method for controlling number of revolution based on the nonsingular terminal of two degrees of freedom High-Order Sliding Mode, when eliminating the controlled quentity controlled variable buffeting, has realized the Fast Convergent of motor speed, and load disturbance is had stronger robustness.

Description of drawings

Fig. 1 is permagnetic synchronous motor control vector method block diagram;

Fig. 2 is the nonsingular terminal control block diagram of two degrees of freedom High-Order Sliding Mode of the present invention;

Fig. 3 is the Emulation of Electrical Machinery speed waveform curve of two degrees of freedom High-Order Sliding Mode control of the present invention;

Fig. 4 is the Emulation of Electrical Machinery speed waveform curve of conventional PI control.

Among Fig. 1,1. inverter, 2.PMSM module, 3. signal deteching circuit, 4.Clark conversion, 5.Park conversion, 6. speed measuring coder, the 7. outer ring controller of the nonsingular terminal control of two degrees of freedom High-Order Sliding Mode, 8. anti-Park conversion, 9.SVPWM module.

Embodiment

A kind of method for controlling permanent magnet synchronous motor adopts vector control system, and vector control system comprises speed outer shroud and current inner loop two parts, mainly contains main circuit, current signal detection circuit 3 and control circuit; Referring to Fig. 1, main circuit comprises inverter 1 and PMSM module 2, and current signal detection circuit 3 detects the three-phase current of motor under the three phase static coordinate system by Hall element, gets two-phase output current i wherein _A, i _B, through Clarke conversion 4, the current value i under convert to static two phase coordinate systems _α, i _β, at speed ring, given rotating speed w ^*Compare with the feedback speed w that encoder 6 records, after regulating through the outer ring controller 7 of the nonsingular terminal control of two degrees of freedom High-Order Sliding Mode, the q shaft current i under the output rotor rotating coordinate system _q ^*,, the current value i under static two phase coordinate systems _α, i _βAnd rotor angle θ is converted to the two-phase feedback calculating exciting current current i under the rotor coordinate system through Park conversion 5 _dWith torque current i _q, given exciting current i _d ^*Calculate exciting current i with feedback _dCompare, after regulating through current PI, obtain the d axle output voltage u of two cordic phase rotators _dTorque current i _q ^*With feedback calculating torque current i _qAfter comparing, after the current PI adjusting, obtain the q axle output voltage u of two cordic phase rotators _qThis moment, two phase voltage u under the rotating coordinate system _qWith u _dThrough two phase voltage u under convert to static two phase coordinate systems after the Park inverse transformation 8 _α, u _β, through the adjusting of SVPWM module 9, produce the PWM ripple, through after the three-phase inverter, drive motors work.

Main feature of the present invention is, with the nonsingular terminal sliding mode controller replacement of PI controller employing two degrees of freedom high-order of original vector control system der Geschwindigkeitkreis.The given rotating speed w that is input as motor of the nonsingular terminal sliding mode controller of two degrees of freedom high-order ^*Then poor with the actual feedback rotating speed w of motor judge the error size of given rotating speed and feedback rotating speed.When speed error hour, the exciting current i of output _q ^*To calculate by the nonsingular terminal control unit of simple High-Order Sliding Mode to realize; The nonsingular terminal sliding mode control of two degrees of freedom high-order is output as the output i of the nonsingular terminal sliding mode control of high-order when speed error is larger _q ^*Output and compensating gain sum for the nonsingular terminal sliding mode of high-order.Wherein the compensating gain here is that the coefficient that multiply by with speed error obtains, the change that the torque current of output also can be real-time in the time of the speed error real time altering like this, so can be more effective regulating system, so that motor speed is more steady, thereby reduced the fluctuation of rotating speed, reached and control preferably effect.

Fig. 2 medium speed deviation be judge rotating speed error size, if when the rotating speed deviation is larger, the output sum that the nonsingular terminal sliding mode of compensating gain and high-order is controlled is i _q ^*If speed error hour, then compensating gain is zero, i.e. torque current i _q ^*Output for the nonsingular terminal sliding mode control of simple high-order.Wherein the nonsingular terminal sliding mode controller's design of high-order is as follows:

The control target of der Geschwindigkeitkreis controller is motor actual speed energy accurate tracking speed preset, and the Parameter Perturbation such as load disturbance and frictional resistance has complete robustness to external world, the given signal i of the friendship shaft current of output smoothing _q ^*Order; Given signal is ω ^*, suppose ω ^*Enough level and smooth, almost everywhere has 2 rank continuous derivatives, the definition error state:

e _ω=ω ^*-ω

（1）

According to the permanent magnet synchronous motor state equation, can get the speed error system state equation and be:

${\stackrel{\·}{e}}_{\mathrm{\ω}}={\stackrel{\·}{\mathrm{\ω}}}^{*}-\stackrel{\·}{\mathrm{\ω}}={\stackrel{\·}{\mathrm{\ω}}}^{*}-\frac{{\mathrm{p\ψ}}_f}{J}{i}_q^{*}+\frac{B}{J}\mathrm{\ω}+\frac{T_L}{J}---\left(2\right)$

Error system state equation (2) is 1 to the relative rank of error state (1), therefore can by 2 rank or 2 rank above sliding formwork control realization system without buffeting, namely smoothly buffet without high frequency.Here der Geschwindigkeitkreis adopts 2 rank sliding formwork controls, makes error state e _ωHave the Second Order Sliding Mode motion state:

For realizing error state e _ωThe motion of 2 rank sliding formworks, design following nonsingular terminal sliding mode face:

$l_{\mathrm{\ω}}=e_{\mathrm{\ω}}+r{{\stackrel{\·}{e}}_{\mathrm{\ω}}}^{p/q}---\left(3\right)$

In the formula, γ〉0, p, q are odd number, and 1＜p/q＜2.According to nonsingular terminal sliding mode convergence property, design appropriate sliding formwork control law so that nonsingular terminal sliding mode face (3) converges to zero in finite time, i.e. l _ω=0.Systematic error state e _ωEnter the terminal sliding mode motion state, will in finite time, arrive 2 rank sliding formwork motions.

Select nonsingular terminal sliding mode face (3) and design control law as follows:

$\left\{\begin{array}{c}{u}_q=u_{\mathrm{qeq}}+u_{\mathrm{qn}}\\ u_{\mathrm{qeq}}={{\stackrel{\·}{\mathrm{Li}}}_q}^{*}+{\mathrm{Lp\ωi}}_d+R_s{i}_q+{\mathrm{p\ψ}}_f\mathrm{\ω}\\ u_{\mathrm{qn}}=L{\∫}_0^t[\frac{1}{\mathrm{\γ}}\frac{q}{p}{{\stackrel{\·}{e}}_q}^{2-p/q}+k_1\mathrm{sgn}\left(s_q\right)+k_2{s}_q]\mathrm{dt}\end{array}\right.---\left(4\right)$

Wherein, k ₁, k ₂Be parameter.

If select Liapunov function to be: v _ω(t)=0.5l _ω ²(t)

To v _w(t) the time differentiate gets:

${\stackrel{\·}{v}}_{\mathrm{\ω}}\left(t\right)=l_{\mathrm{\ω}}\left(t\right)l_{\mathrm{\ω}}\left(t\right)$

$=\frac{l_{\mathrm{\ω}}{\mathrm{\γ}}_1{p}_1}{q_1}{{\stackrel{\·}{e}}_{\mathrm{\ω}}}^{p_1/q_1-1}[{\stackrel{\·\·}{e}}_{\mathrm{\ω}}+\frac{q_1}{{\mathrm{\γ}}_1{p}_1}{{\stackrel{\·}{e}}_{\mathrm{\ω}}}^{2-p_1/q_1}]$

$=\frac{l_{\mathrm{\ω}}{\mathrm{\γ}}_1{p}_1}{q_1}{{\stackrel{\·}{e}}_{\mathrm{\ω}}}^{p_1/q_1-1}[-(k_1+{\mathrm{\η}}_1)\mathrm{sgn}{l}_{\mathrm{\ω}}+\frac{T_L}{J}-{\mathrm{\η}}_2{l}_{\mathrm{\ω}}]$

$\≤{-\mathrm{\γ}}_1(p_1/q_1){{\stackrel{\·}{e}}_{\mathrm{\ω}}}^{p_1/q_1-1}\left({\mathrm{\η}}_1\right|l_{\mathrm{\ω}}|+{\mathrm{\η}}_2{l_{\mathrm{\ω}}}^2)$

As can be seen from the above equation, work as l _ω≠ 0 o'clock, because

Then

And if only if

The time,

And work as e _ω≠ 0 can prove not to be a stable state, namely

Can not keep always.So system is in finite time arrival and keep nonsingular terminal sliding mode l _ω=0, e then _ωTo in finite time, restrain.By regulating parameter p ₂, q ₂, k ₁, k ₂Error e that can adjusting rotary speed _ωConvergence rate.If provable selecting type (3) can be restrained for the nonsingular terminal sliding mode plane system that is thus.

In control procedure, also have certain high dither for the nonsingular terminal of High-Order Sliding Mode, adopt the two degrees of freedom control principle, in the nonsingular terminal of above-mentioned High-Order Sliding Mode, added the two degrees of freedom control algolithm and to reach system has better been controlled.Concrete control method block diagram is done speed preset and speed feedback poorly to obtain the rotating speed deviation as shown in Figure 2, if the rotating speed deviation is in the acceptable scope then can directly obtain i through the nonsingular terminal control of High-Order Sliding Mode _q ^*Same i again _qDo poor after as the input of electric current loop PI controller; If when the rotating speed deviation is larger, i then _q ^*Be the output of the nonsingular terminal control of High-Order Sliding Mode and the compensating gain sum of two degrees of freedom feedback.Adjustment i that so just can be real-time _q ^*Size obtain preferably rotating speed control purpose.

Systematic error size control among Fig. 2 is to adopt piecewise function, carries out two degrees of freedom in the time of larger to speed error and regulates, and does not process when speed error is less.If error state is

Then order:

$\mathrm{\ξ}=\left\{\begin{array}{cc}{\mathrm{\ξ}}_1-e_{\mathrm{\ω}},& e_{\mathrm{\ω}}\≥{\mathrm{\ξ}}_1\\ 0,& {\mathrm{\ξ}}_2\≤e_{\mathrm{\ω}}\≤{\mathrm{\ξ}}_1\\ {\mathrm{\ξ}}_2-e_{\mathrm{\ω}},& e_{\mathrm{\ω}}\≤{\mathrm{\ξ}}_2\end{array}\right.---\left(5\right)$

Wherein, ξ ₁And ξ ₂Be the feedback switching point, and ξ ₁0, ξ ₂＜0, ξ ₁, ξ ₂Be constant.By selecting suitable ξ ₁, ξ ₂Size can the Adjustment System performance.Work as e _ω〉=ξ ₁The time, system is positive feedback; Work as e _ω≤ ξ ₂The time, system is negative feedback; Work as ξ ₁≤ e _ω≤ ξ ₂The time think that acceptable error range do not process this system still for the single-degree-of-freedom control system.Can control dynamically in real time the two degrees of freedom feedback loop thus, thereby reach better system control performance.

Control method of the present invention has the advantage of the nonsingular terminal control of High-Order Sliding Mode and two degrees of freedom control method simultaneously.

The present invention is based on the control of the nonsingular terminal control system of two degrees of freedom High-Order Sliding Mode, has simple in structurely, is easy to realize, robustness is good, have the fast and little advantage of tracking error of speed responsive, improved Systems balanth, effectively improved the dynamic and static runnability of system.

In order to verify the feasibility of two degrees of freedom High-Order Sliding Mode control method, this paper has carried out emulation at the MATLAB platform, and the permagnetic synchronous motor parameter of selection is: R=4.96 Ω, L _d=0.0085mH, L _q=0.0085mH, B=0, number of pole-pairs p=2, ψ=0.375Wb, J=.26 * 10 ^-5Kg.m ², simulation result is as follows:

Fig. 3, Fig. 4 are respectively the Emulation of Electrical Machinery speed waveform curve of the given rotating speed control of two degrees of freedom High-Order Sliding Mode and conventional PI control when being 1500r/min.The load of motor impact 5Nm when 0.2s, as seen from Figure 3 the startup stage speed overshoot only for compare the control of two degrees of freedom High-Order Sliding Mode about 0.035s with PI control very fast dynamic property is arranged less than 10r/min and adjusting time, when 0.2s during system's shock load, the control of two degrees of freedom High-Order Sliding Mode can arrive stable state about 0.202s, and the rotating speed landing that loads rear motor only is about 5r/min, compare with traditional PI and can get back to faster stable state, and fluctuation is less.Illustrate that this control method has preferably robustness to load, and quick performance.

Claims (1)

1. method for controlling permanent magnet synchronous motor is characterized in that: adopt vector control system, vector control system comprises speed outer shroud and current inner loop two parts, and the PI controller of der Geschwindigkeitkreis adopts the nonsingular terminal sliding mode controller of two degrees of freedom high-order to replace; The given rotating speed w that is input as motor of the nonsingular terminal sliding mode controller of two degrees of freedom high-order ^*Poor with the actual feedback rotating speed w of motor judged the error size of given rotating speed and feedback rotating speed, when speed error during less than ξ, and the exciting current i of output _q ^*To calculate by the nonsingular terminal control unit of simple High-Order Sliding Mode to realize; When speed error during greater than ξ the nonsingular terminal sliding mode control of two degrees of freedom high-order be output as the output i of the nonsingular terminal sliding mode control of high-order _q ^*Output and compensating gain sum for the nonsingular terminal sliding mode of high-order; Wherein the large I of ξ is according to actual conditions and requirements set.

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