A Novel Charging Control for D-EPC with DC Power Sources Connected in Series

Abstract

A new multiple DC-inputs direct electric-power converter (D-EPC) was proposed. It can be applied to motor-drive systems with two direct-current (DC) power sources. The D-EPC can charge a DC power source with motoring by another DC power source. This charging is controlled by the voltage command multiplied by a power distribution ratio of more than 1.0 for the DC power source supplying power to the motor and another DC power source. If charging power is required in the condition of phase voltage saturation, the phase voltage command calculated using the power distribution ratio of more than 1.0 cannot be increased to more than the phase voltage limit. This paper proposes a new charging control for D-EPCs by controlling the switches on the free-wheel current path. The distribution ratio of this proposed control does not exceed 1.0. The simulation results showed that one DC power source can be charged with motoring by another DC power source using the proposed charging control.