Single current sensor control for PWM inverter fed AC motor drives under over-modulation mode

In order to lower the cost and expand the working range of PWM inverter fed AC motor drives, the control methods under over-modulation conditions with only a DC link current sensor are investigated. A basic phase current reconstruction algorithm is developed for PWM inverters. Taking the over-modulation into account, the space vector PWM strategy and the switching state distribution for PWM inverter are analyzed in detail. In order to realize the DC link current detection under over-modulation conditions, an adjustment scheme of the switching state distribution is proposed. Based on these works, the over-modulation vector control of PWM inverter fed AC motor drive with only a DC link current sensor is implemented. Simulation and experimental results demonstrate the feasibility and effectiveness of the proposed control algorithm.