Control Policies to Prevent PMSMs From Losing Control Under Field-weakening Operation

Field-weakening technology is important for permanent magnet synchronous machine（PMSM） control in wide speed range applications.In deep field-weakening operation,saturation of current regulators may lead to losing control and even damages.This paper analyzed the reason why current saturation happens for conventional field-weakening algorithm.It is concluded that precise limitation of d-axis current is necessary to keep the system under control.New control algorithm is proposed to prevent losing control from happening.It is verified by experimental result that the speed range of PMSM is enhanced by the proposed field-weakening algorithm.