Control of PM Synchronous Motor with Hybrid Speed Controller with Gain Scheduling for Electric Propulsion

Abstract

Due to the increased operating efficiency and reduced carbon emissions, the number of battery driven electric vehicles (EVs) plying on the roads is gradually increasing. It is estimated that in the future, the electric vehicles will phase out the internal combustion engine-based vehicles, and the automobile sector will be dominated by EVs. In order to increase the distance travelled by EV per full charge of the battery, it is important to increase the efficiency of the propulsion system. Hence, permanent magnet synchronous motors (PMSMs), which have higher operating efficiency, as compared to the induction motors, are largely preferred for electric propulsion. The PMSM drive generally employs field-oriented control (FOC). In FOC, the operation of speed controller is critical as it decides the reference torque for the inner control loop. As the proportional–integral (PI) speed controllers with constant gains suffer from performance degradation under disturbances, gain scheduling is employed. To further improve the dynamic performance of the speed controller, this paper reports electric propulsion with hybrid gain-scheduled PI speed controller for the FOC controlled PMSM. The weights for the gain-scheduled PI controller and the fuzzy equivalent proportional controller are determined by the hyperbolic tangent function. The output of the reported speed controller is the weighted average of the two controller outputs. This results in computational simplicity and improved dynamic performance. The EV performance with this hybrid speed controller is analysed for acceleration, deceleration and cruising conditions.