A comparison of discrete-time complex vector current regulators at low frequency ratio

This paper focuses on the performance and stability of discrete-time domain complex vector PI (CVPI) current regulator operating at low carrier-wave frequency ratio. A novel and accurate discrete-time induction motor model using Pole-zero Matching method is proposed with consideration of control delay and PWM delay. On the foundation of this, an explicit comparison of discrete-time CVPI using Front-Euler method, Back-Euler method, Tustin method and Direct Design method is made to investigate the limit frequency ratio for different discrete-time CVPI topologies. The simulation results are provided with the same conditions except the adapted current regulator for a relatively objective comparison.