PWM Technique for Expanding the Average Current Reconstruction Region in a Three-Phase Inverter Using a Single DC-Link Current Sensor

This paper proposes a PWM technique to expand the recoverable region of the average current in a three-phase inverter system by using a single DC-link current sensor. Voltage injection method is widely used to avoid the non-recoverable current region. However, in low-impedance motors, such as ultra-high-speed motors, significant current ripple can occur, leading to a decrease in control performance because of the error between the recovered and actual current. Although the switching signal split technique has been studied for average current reconstruction, this approach limits the current measurement capability to the low-speed (low-modulation) region of the motor. Therefore, this study aims to improve the conventional switching signal split technique based current reconstruction method and propose a strategy to expand the recoverable average current region.