Permanent Magnet Brushless Dc Motor Constant Power Field Weakening Control

Permanent Magnet Blushless Direct Current Motor(PMBLDCM) has been paid more attention in the past two decades by researchers in the motor and control system fields because of its excellent performance, for example, small cubage, great power density and high efficiency. We can foresee the further development about PMBLDCM and its control system with the price debased of permanent magnet material and manufacture of rotor. PMBLDCM may have a wonderful foreground in many fields.To achieve the flux-weakening control for a PMBLDCM on the base of hybrid rotor structure, the paper proposes an effective control strategy-"twain mode control": adopting PWM method to achieve constant torque operation blow the base-speed, and regulating the phase angle of current leading EMF to gain the equivalent demagnitigation of armature reaction and to achieve constant power operation above the base-speed. The control system composed by DSP+IPM realized this control strategy successfully and achieved nearly three-time flux-weakening operation speed region with constant power.