Structure-variable sliding mode control of interior permanent magnet synchronous motor in electric vehicles with improved flux-weakening method

A kind of flux-weakening control method based on speed loop structure-variable sliding mode controller is proposed for interior permanent magnet synchronous motor in electric vehicles. The method combines maximum torque per ampere with vector control strategy to control electric vehicle’s interior permanent magnet synchronous motor. During the flux-weakening control phase, the anti-windup integral controller is introduced into the current loop to prevent the current regulator from entering the saturated state. At the same time, in order to further improve the utilization rate of the direct current bus voltage and expand the flux-weakening regulating range, a space vector pulse-width modulation over-modulation unit is employed to contravariant the direct current bus voltage. Comparing with the conventional proportional–integral controller, the proposed sliding mode control algorithm shows that it has more reliable control performance. In addition, more prominent flux-weakening performance of the proposed flux-weakening method is illustrated by numerical simulation comparison.