Research On Current Optimal Control Strategy Of Hybrid Excitation Synchronous Motor Speed Control System

Hybrid excitation synchronous motor is a new type of composite structure motor,which has the advantages of wide speed range,strong load capacity,high operating efficiency,etc.It is especially suitable for high-precision and high-reliability AC speed regulation systems.However,the hybrid excitation synchronous motor speed control system is high-order,non-linear,and strongly coupled.The electromagnetic torque has a nonlinear relationship with the axis component,the axis component,and the excitation current of the armature current,and the currents are coupled with each other.Therefore,it is very important to study how to optimize the configuration of armature current and excitation current and realize the decoupling of current to improve the control performance of hybrid excitation synchronous motor speed control system.First,a comparative study of several current distribution algorithms using the rated speed as the weak magnetic base speed,it is concluded that the current distribution algorithm is controlled by the id=0-copper consumption minimum control algorithm in the low speed region and the copper field weakening control algorithm in the high speed region It is simple and can achieve the conclusion of minimum copper consumption in the full speed range.Aiming at the problem that the current distribution algorithm with the rated speed as the weak magnetic base speed cannot make full use of the inverter output voltage,a minimum current distribution algorithm for copper consumption based on voltage closed-loop feedback is proposed.Simulation experiments show that the system using the minimum current distribution algorithm of copper consumption based on voltage closed-loop feedback can achieve accurate tracking of speed and current in the full speed range,and widen the speed regulation range of the motor and improve the inverter output voltage utilization rate.Secondly,for the nonlinear coupling between the current components and the speed in the hybrid excitation synchronous motor speed control system,a voltage feedforward controller and an input-output feedback linearization controller are designed.Simulation experiments show that,compared with the traditional PI control algorithm,the voltage feedforward control algorithm and the input and output feedback linearization control algorithm both achieve current decoupling,which improves the control performance of the system,and the voltage feedforward control algorithm improves the ability of the system to respond to speed.It is better than the feedback linearization control algorithm,but the torque ripple and current ripple at steady state are not as obvious as the feedback linearization control algorithmFinally,to further improve the dynamic response performance of the input-output feedback linearization controller,a sliding mode controller is used to redesign the decoupled linear subsystem.Aiming at the problem that the traditional exponential approach law has a switching function that will bring about high-frequency chattering,a hybrid approach law that introduces terminal attractors into the exponential approach law is proposed,and a sliding mode controller is designed based on the hybrid approach law.Simulation experiments show that the feedback linearization decoupling sliding mode controller designed further improves the dynamic response performance of the system and verifies that the proposed control algorithm is correct and effective.