Model Predictive Current Control Of Permanent Magnet Synchronous Motor Based On Sliding Mode Observer

Permanent magnet synchronous motor(PMSM)has been widely used in various industrial applications due to its high reliability,high power density and high efficiency.At the same time,various advanced control strategies have been used to drive permanent magnet synchronous motors.Model predictive control has been widely used in AC motor control systems due to its simple principle,multi-variable control and easy consideration of nonlinear constraints.Model predictive current control(MPCC)is an important branch of model predictive control.MPCC takes current as the control object and does not need to design weight coefficients.Therefore,MPCC is more suitable for PMSM drive field.Although the MPCC has good control performance,its essence based on the mathematical model of the controlled object still exists,making it very sensitive to change in motor parameters.Meanwhile,the MPCC is composed of a current loop and a speed loop.The controller used in the speed loop usually is a linear PI controller,PMSM is a high-order,nonlinear,and strongly coupled system,and the linear PI controllers in a nonlinear system inevitably cannot control the motor accurately.Aiming at the problem that MPCC is sensitive to changes in motor parameters and the use of PI controllers in model predictive current control restricts the further improvement of control performance,this paper takes PMSM as the research object and studies a model predictive current control based on sliding mode observer.Firstly,the influence of parameter changes on the current prediction error is analyzed.On this basis,a sliding mode disturbance observer is designed to observe the lumped disturbance including the disturbance caused by the parameter mismatch and the uncertain disturbance,and the lumped disturbance is compensated into the prediction model to reduce the sensitivity of the control system to the motor parameter.In addition,the mechanical motion equation of the PMSM is processed,the deadbeat predictive controller is designed to replace the PI controller in the MPCC,and a sliding mode load torque observer is constructed to observe the load torque,so that the control system has good anti-load disturbance and dynamic response performance.This paper uses MATLAB simulation software to establish a simulation model of the model predictive current control of permanent magnet synchronous motor based on sliding mode observer,and the simulation research is carried out.At the same time,experimental research is carried out on the permanent magnet synchronous motor control system driven by a two-level voltage source inverter.Simulation and experimental results show that,compared with model predictive current control,the model predictive current control of permanent magnet synchronous motor based on sliding mode observer has stronger anti-load disturbance ability and faster dynamic response performance.Moreover,when the motor parameters are mismatched,the model predictive current control based on the sliding mode observer still has good current tracking performance,which reduces the dependence on the motor parameters.