Research On The Application Of New Reaching Law Sliding Mode Algorithm In PMSM

At present,permanent magnet synchronous motor has been widely used in daily life,production and scientific research,but there are two problems in motor control.First,the motor is a multivariable,nonlinear complex system,the traditional PI controller can not adapt to this nonlinear environment.Problem two,mechanical position sensor cost is high,special occasions can not adapt.Sliding mode is an adaptive algorithm,which can adapt to the nonlinear environment well.Sliding mode controller has better performance than PI controller in speed loop.Although the sliding mode algorithm is simple and easy to design,the inherent chattering in the traditional sliding mode algorithm limits the wide application of the sliding mode controller algorithm and the sliding mode observer algorithm.In the third chapter,a controller without speed overshoot and strong anti-load disturbance ability is designed for problem one.In chapter 4,an observer which can replace mechanical position sensor is designed for problem 2.In addition to these two problems,this paper also needs to improve the chattering of sliding mode algorithm itself.Aiming at the sliding mode jitter caused by the discontinuous switching function at the zero point in the traditional sliding mode controller,the quasi-sliding mode function method is used to improve the sliding mode jitter,and the integral sliding mode surface is used to reduce the high frequency noise.The quasi-sliding mode function method is to replace the traditional sign switching function with the quasi-sliding mode function.If the parameters are selected properly,the quasi-sliding mode function can be smoothly transitioned at zero point.This paper summarizes nine quasi-sliding mode functions.In the traditional reaching law,there is a contradiction between the size of the sliding mode gain and the speed of the moving point in each stage.Improper resolution of this contradiction will lead to slow system response or excessive sliding mode chattering or even break the steady state.In order to solve this contradiction reasonably,several new reaching law controllers are designed in this paper.Divided into exponential reaching law,general reaching law,power reaching law sliding mode controller.Finally,a windup exponential reaching law sliding mode controller is designed for speed overshoot.Compared with the traditional reaching law sliding mode controller,the four controllers designed in this paper have better overshoot suppression effect and stronger anti-interference ability under sensorless vector control.The Windup exponential reaching law sliding mode controller and the exponential reaching law sliding mode controller achieve zero overshoot.The realization of sensorless position control technology depends on the observer deduced by various algorithms.The biggest problem of traditional sliding mode observer is that when the motor reaches steady state,it will fluctuate greatly near the rated speed,that is,the sliding mode inherent chattering phenomenon(20rmp).In order to reduce the steady-state motor speed chattering,improve system robustness.The sliding mode observers of five quasi-sliding mode functions are derived and simulated to verify the chattering reduction effect.To verify that the reaching law can also reduce the inherent chattering of sliding mode system,the traditional reaching law,exponential reaching law and fuzzy super-twisting sliding mode observer are reproduced.At the same time,a new reaching law sliding mode observer(0.8rmp)optimized by hyperbolic tangent function and a new exponential reaching law sliding mode observer(0.34rmp)optimized by sinusoidal composite function are designed.The chattering reduction effect of the latter can be approximated to the fuzzy super-twisting sliding mode observer(0.3rmp).Finally,the windup first-order new reaching law sliding mode controller combined with the new exponential reaching law sliding mode observer improved by the sinusoidal composite quasi-sliding mode function is used for simulation analysis.This combination not only successfully suppresses the speed overshoot phenomenon,but also achieves a good chattering reduction effect and has good robustness.Figure [110] Table [5] Reference [63]...