A DC-Link Voltage Control Scheme for 4-Level Inverter at Low Modulation Index

4-레벨 인버터를 위한 저변조지수 영역의 DC-링크 전압 제어기법

An effective Carrier-Based PWM scheme that enables the instantaneous quality of each branch point voltage of a diode clamped 4-level inverter to be reduced at a low modulation index is described. This scheme presents a computed zero sequence voltage of PWM by the feedback of both DC-link voltages and load currents. The proposed PWM scheme enables to increase the controllable region of DC-link voltage and makes it possible to operate with small DC-link capacitors. The validity of the proposed PWM scheme is verified by simulation results.