Research on the Control of Magnetic Weakening Scheme for the Voltage Utilization Rate of Hybrid Transmission

This paper proposes a field-weakening control method for permanent magnet synchronous motor (PMSM) current regulators based on the ratio of voltage-frequency ratio and voltage utilization rate when the motor speed exceeds the field-weakening speed; that is, the direct-axis offset current id is generated through the action of field-weakening feedforward and field-weakening PI regulator, and the control of field-weakening speed can directly adjust the demagnetization effect of id to achieve field-weakening control of PMSM. The field-weakening control method of PMSM current regulators with the outer loop of voltage utilization rate is adopted. It is proposed to use the phase-locked loop control method to decode the motor position signal in a closed loop and calculate the motor speed. The fluctuation of the position signal is reduced and the signal is more stable. This paper realizes constant power speed regulation based on high voltage utilization rate and field-weakening control method at high-speed operation above the base speed, which greatly improves the dynamic performance and system efficiency of the system.