Efficiency optimization of IPMSM for urban rail traction based on switching frequency optimization control

Harmonic voltage and harmonic current will produce core loss and copper loss to reduce the operation efficiency in the direct torque control system of interior permanent magnet synchronous motor (IPMSM-DTC) for urban rail traction. Efficiency optimization control strategy, which is based on switching frequency optimization, is presented for the problem. The adaptive hysteresis band value and optimized null vector distribution method are adopted to utilize the switching frequency of power device and optimize null vector to PWM. Efficiency optimization control system is implemented using a STM32F103 embedded microcontroller. Experimental results prove that the harmonic waveform of inverter is restrained, the switching times and switching current are decreased, the core loss and copper loss are reduced to increase the efficiency of IPMSM and the dynamic and static performances of the system are improved.