Flux-Weakening in PMSM Drives: Analysis of Voltage Angle Control and the Single Current Controller Design

Voltage angle control not only can solve the problem that two current regulators of traditional algorithms conflict with each other but also has the advantage of maximum utilization of the dc-link voltage. Based on the basic equations of permanent-magnet synchronous motors (PMSM) in i(d)-i(q) coordinate plane, the principle of voltage angle control is analyzed and a single q-axis current regulator-variable voltage angle control method is proposed as the novel approach for the flux-weakening operation of PMSM over a wide range of speed in motoring and generating mode. The proposed method enables the fast dynamic response of current when current reference changes and eliminates the transition between the motoring and generating operation. The results of simulation and experiment demonstrate the effectiveness of the proposed control method.