CN102969968B - 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 industrial production automation field will be more and more extensive.But because of the multivariable system that permagnetic synchronous motor is a high-order, non-linear, close coupling, also there is the uncertainty such as Parameter Perturbation, load disturbance simultaneously, therefore will carry out high performance control to it more difficult.Have for the control method of PMSM at present and be much suggested, as adaptive control, fuzzy control, neural net, Active Disturbance Rejection Control etc.But these are applied in actual engineering because method comparison complexity seldom has.

Sliding moding structure has good consistency because of it to system parameters uncertainty and external disturbance, start to be widely used in electric machine speed regulation field, Sliding mode variable structure control has strong robustness, realizes simple advantage, in parameter of electric machine change and when there is disturbance, still the performance of satisfaction guaranted, is thus subject to the attention of increasing Chinese scholars.But due to the discontinuity of its control action, be easy to that system is produced and buffet, greatly have impact on the application in working control.Chattering phenomenon is caused under the effect that high frequency switching controls can perturb in disturbance and model parameter.And the amplitude scaled versions relation that the amplitude of buffeting and disturbance and model parameter perturb.In electric machine control system, buffeting can produce pulsation thrust, the stationarity of influential system and positioning precision, increases energy loss.The non-singular terminal sliding formwork proposed in recent years can make system mode arrive balance point in finite time, and steady-state tracking precision is high, but still there is buffeting.Application saturation function replaces switch function, and emulation shows that it weakens buffeting to a certain extent, but also reduces the robustness of system simultaneously.Application observer observation load disturbance is also compensated, the method, by reducing nonlinear terms, can reduce preferably to buffet, but add the complexity of system because adding observer, and the existence of system chatter affects accuracy of observation, be actually difficult to reach desirable improvement effect.

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 two degrees of freedom high-order non-singular terminal sliding mode controller to replace; The given rotating speed w being input as motor of two degrees of freedom high-order non-singular terminal sliding mode controller ^*with the difference of the actual feedback rotating speed w of motor, judge given rotating speed and the error size feeding back rotating speed, when speed error is less than ξ, the exciting current i of output _q ^*calculated by simple High-Order Sliding Mode non-singular terminal controller to realize; The output that two degrees of freedom high-order non-singular terminal sliding formwork controls when speed error is greater than ξ is the output i that high-order non-singular terminal sliding formwork controls _q ^*for output and the compensating gain sum of high-order non-singular terminal sliding formwork; Wherein the large I of ξ is according to actual conditions and requirements set.

The present invention has following beneficial effect:

1, the two degrees of freedom High-Order Sliding Mode non-singular terminal of the PI controller in der Geschwindigkeitkreis controls to replace by adopting by the present invention, switching item in traditional sliding-mode control is added on the derivative of TSM control method, therefore, effectively reduce the buffeting problem of sliding moding structure in system control process, thus also improve Systematical control precision, make rotating speed be able to effectively be converged near balance point.

2, the present invention proposes the permagnetic synchronous motor method for controlling number of revolution based on two degrees of freedom High-Order Sliding Mode non-singular terminal, while elimination controlled quentity controlled variable is buffeted, achieves the Fast Convergent of motor speed, and has stronger robustness to load disturbance.

Accompanying drawing explanation

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

Fig. 2 is two degrees of freedom High-Order Sliding Mode non-singular terminal control block diagram 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.

In Fig. 1,1. inverter, 2.PMSM module, 3. signal deteching circuit, 4.Clark converts, and 5.Park converts, 6. speed measuring coder, and 7. two degrees of freedom High-Order Sliding Mode non-singular terminal controls outer ring controller, 8. anti-Park conversion, 9.SVPWM module.

Embodiment

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, mainly contains main circuit, current signal detection circuit 3 and control circuit; See 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 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 system _α, i _β, at speed ring, given rotating speed w ^*compared with the feedback speed w recorded with encoder 6, control after the adjustment of outer ring controller 7 through two degrees of freedom High-Order Sliding Mode non-singular terminal, the q shaft current i under output rotor rotating coordinate system _q ^*, the current value i under static two phase coordinate systems _α, i _βand rotor angle of electric machine θ is through Park conversion 5, the two-phase feedback be converted under rotor rotating coordinate system calculates exciting current current i _dwith torque current i _q, given exciting current i _d ^*exciting current i is calculated with feedback _dcompare, after current PI regulates, obtain the d axle output voltage u of two cordic phase rotators _d; Torque current i _q ^*with feedback calculating torque current i _qafter comparing, after current PI regulates, obtain the q axle output voltage u of two cordic phase rotators _q; This moment, two phase voltage u under rotating coordinate system _qwith u _dtwo phase voltage u after Park inverse transformation 8 under convert to static two phase coordinate system _α, u _β, through the adjustment of SVPWM module 9, produce PWM ripple, after three-phase inverter, drive motors work.

Main feature of the present invention is, is adopted by the PI controller of original vector control system der Geschwindigkeitkreis two degrees of freedom high-order non-singular terminal sliding mode controller to replace.The given rotating speed w being input as motor of two degrees of freedom high-order non-singular terminal sliding mode controller ^*with the difference of the actual feedback rotating speed w of motor, then judge given rotating speed and the error size feeding back rotating speed.When speed error is less, the exciting current i of output _q ^*calculated by simple High-Order Sliding Mode non-singular terminal controller to realize; The output that two degrees of freedom high-order non-singular terminal sliding formwork controls when speed error is larger is the output i that high-order non-singular terminal sliding formwork controls _q ^*for output and the compensating gain sum of high-order non-singular terminal sliding formwork.Wherein compensating gain is here obtained by the coefficient that is multiplied by of speed error, the change that the torque current of output also can be real-time when speed error changes in real time time like this, so can more effective regulating system, make motor speed more steady, thus reduce the fluctuation of rotating speed, reach good control effects.

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

The control objectives 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 quadrature axis current Setting signal i of output smoothing _q ^*.Order; Setting signal is ω ^*, suppose ω ^*enough level and smooth, almost everywhere has 2 rank continuous derivatives, definition error state:

e _ω=ω ^*-ω

（1）

According to permanent magnet synchronous motor state equation, can obtain speed error system state equation is:

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

The Relative order of error system state equation (2) to error state (1) is 1, therefore by 2 rank or 2 rank above sliding formwork control realization system without buffeting, namely smoothly can buffet without high frequency.Here der Geschwindigkeitkreis adopts 2 rank sliding formworks to control, and makes error state e _ωthere is Second Order Sliding Mode motion state: for realizing error state e _ω2 rank sliding formworks motions, design following non-singular terminal sliding-mode surface:

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

In formula, γ >0, p, q are odd number, and 1 < p/q < 2.According to non-singular terminal sliding formwork convergence property, design appropriate sliding formwork control law and make non-singular terminal sliding-mode surface (3) be zero at Finite-time convergence, be i.e. l _ω=0.Systematic error state e _ωenter terminal sliding mode motion state, 2 rank sliding formwork motions will be arrived in finite time.

Select non-singular terminal sliding-mode surface (3) design control law is as follows:

$\left\{\begin{array}{c}{u}_q=u_{\mathrm{qeq}}+u_{\mathrm{qn}}\\ u_{\mathrm{qeq}}={{\stackrel{\&CenterDot;}{\mathrm{Li}}}_q}^{*}+{\mathrm{Lp\&omega;i}}_d+R_s{i}_q+{\mathrm{p\&psi;}}_f\mathrm{\&omega;}\\ u_{\mathrm{qn}}=L{\&Integral;}_0^t[\frac{1}{\mathrm{\&gamma;}}\frac{q}{p}{{\stackrel{\&CenterDot;}{e}}_q}^{2-p/q}+k_1\mathrm{sgn}\left(s_q\right)+k_2{s}_q]\mathrm{dt}\end{array}\right.---\left(4\right)$

Wherein, k ₁, k ₂for parameter.

If selection Liapunov function is: v _ω(t)=0.5l _ω ²(t)

To v _wt the differentiate of () time obtains:

${\stackrel{\&CenterDot;}{v}}_{\mathrm{\&omega;}}\left(t\right)=l_{\mathrm{\&omega;}}\left(t\right)l_{\mathrm{\&omega;}}\left(t\right)$

$=\frac{l_{\mathrm{\&omega;}}{\mathrm{\&gamma;}}_1{p}_1}{q_1}{{\stackrel{\&CenterDot;}{e}}_{\mathrm{\&omega;}}}^{p_1/q_1-1}[{\stackrel{\&CenterDot;\&CenterDot;}{e}}_{\mathrm{\&omega;}}+\frac{q_1}{{\mathrm{\&gamma;}}_1{p}_1}{{\stackrel{\&CenterDot;}{e}}_{\mathrm{\&omega;}}}^{2-p_1/q_1}]$

$=\frac{l_{\mathrm{\&omega;}}{\mathrm{\&gamma;}}_1{p}_1}{q_1}{{\stackrel{\&CenterDot;}{e}}_{\mathrm{\&omega;}}}^{p_1/q_1-1}[-(k_1+{\mathrm{\&eta;}}_1)\mathrm{sgn}{l}_{\mathrm{\&omega;}}+\frac{T_L}{J}-{\mathrm{\&eta;}}_2{l}_{\mathrm{\&omega;}}]$

$\&le;{-\mathrm{\&gamma;}}_1(p_1/q_1){{\stackrel{\&CenterDot;}{e}}_{\mathrm{\&omega;}}}^{p_1/q_1-1}\left({\mathrm{\&eta;}}_1\right|l_{\mathrm{\&omega;}}|+{\mathrm{\&eta;}}_2{l_{\mathrm{\&omega;}}}^2)$

As can be seen from the above equation, l is worked as _ωwhen ≠ 0, due to then and if only if time, and work as e _ω≠ 0 can prove not to be a stable state, namely can not keep always.So system arrives at finite time and keeps non-singular terminal sliding formwork l _ω=0, then e _ωwill at Finite-time convergence.By regulating parameter p ₂, q ₂, k ₁, k ₂can the error e of adjusting rotary speed _ωconvergence rate.If provable selecting type (3) can be restrained for the non-singular terminal sliding-mode surface system being thus.

In control procedure, also have certain high dither for High-Order Sliding Mode non-singular terminal, adopt two parameter compensator principle, in above-mentioned High-Order Sliding Mode non-singular terminal, add two parameter compensator algorithm to reach, system is better controlled.Speed preset and velocity feedback as shown in Figure 2, are made difference and are obtained rotating speed deviation by concrete control method block diagram, if rotating speed deviation is within the scope of acceptable, can directly control to obtain i through High-Order Sliding Mode non-singular terminal _q ^*same i again _qas the input of electric current loop PI controller after making difference; If when rotating speed deviation is larger, then i _q ^*the compensating gain sum that the output controlled for High-Order Sliding Mode non-singular terminal and two degrees of freedom are fed back.Adjustment i that so just can be real-time _q ^*size obtain good rotating speed control object.

Systematic error size in Fig. 2 controls to be adopt piecewise function, carries out two degrees of freedom adjustment, do not process when speed error is less time time larger to speed error.If error state is then make:

$\mathrm{\&xi;}=\left\{\begin{array}{cc}{\mathrm{\&xi;}}_1-e_{\mathrm{\&omega;}},& e_{\mathrm{\&omega;}}\&GreaterEqual;{\mathrm{\&xi;}}_1\\ 0,& {\mathrm{\&xi;}}_2\&le;e_{\mathrm{\&omega;}}\&le;{\mathrm{\&xi;}}_1\\ {\mathrm{\&xi;}}_2-e_{\mathrm{\&omega;}},& e_{\mathrm{\&omega;}}\&le;{\mathrm{\&xi;}}_2\end{array}\right.---\left(5\right)$

Wherein, ξ ₁and ξ ₂for feedback switching point, and ξ ₁>0, ξ ₂<0, ξ ₁, ξ ₂for constant.By selecting suitable ξ ₁, ξ ₂size can adjustment System performance.Work as e _ω>=ξ ₁time, system is positive feedback; Work as e _ω≤ ξ ₂time, system is negative feedback; Work as ξ ₁≤ e _ω≤ ξ ₂time to think that acceptable error range does not carry out processing this system be still single-degree-of-freedom control system.Two degrees of freedom feedback loop can be controlled dynamically in real time thus, thus reach better system control performance.

Control method of the present invention has the advantage of the control of High-Order Sliding Mode non-singular terminal and two parameter compensator method simultaneously.

The present invention controls based on two degrees of freedom High-Order Sliding Mode non-singular terminal control system, has structure simple, is easy to realize, robustness is good, there is the advantage that speed responsive is fast and tracking error is little, improve the stability of system, effectively improve the dynamic and static runnability of system.

In order to verify the feasibility of two degrees of freedom high_order sliding mode control method, emulate on MATLAB platform herein, 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 two degrees of freedom high_order sliding mode control and conventional PI control when given rotating speed is 1500r/min.The load of motor impact 5Nm when 0.2s, as seen from Figure 3 startup stage speed overshoot less than 10r/min and regulating time be only about 0.035s to control with PI compared with two degrees of freedom high_order sliding mode control have very fast dynamic property, when 0.2s during system shock load, two degrees of freedom high_order sliding mode control can arrive stable state at about 0.202s, and the motor speed loss loading rear motor is only about 5r/min, can get back to stable state faster compared with traditional PI, and fluctuation is less.Illustrate that this control method has good robustness to load, and quick performance.

Claims (1)

1. a 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 two degrees of freedom high-order non-singular terminal sliding mode controller to replace; The given rotating speed w being input as motor of two degrees of freedom high-order non-singular terminal sliding mode controller ^*with the difference of the actual feedback rotating speed w of motor, judge given rotating speed and the error size feeding back rotating speed, when speed error is less than ξ, the exciting current i of output _q ^*calculated by simple High-Order Sliding Mode non-singular terminal controller to realize; The output i that two degrees of freedom high-order non-singular terminal sliding formwork controls when speed error is greater than ξ _q ^*for output and the compensating gain sum of high-order non-singular terminal sliding formwork; Wherein the large I of ξ is according to actual conditions and requirements set.