A space vector PWM scheme for five-phase current-source converters

Abstract

The most recent literature on multiphase machine drives is based on voltage-source converter (VSC) systems utilizing different modulation techniques. Very little attention is given to the multiphase current-source converters (CSCs). Applying CSCs in high-power multiphase drive systems is promising and can effectively solve many technical problems associated with conventional VSC-based systems. This paper proposes a space vector pulsewidth-modulation (SVPWM) scheme suitable for a five-phase CSC. Generally, in SVPWM-CSCs, a current path should be provided for the dc-link current by ensuring that one pair of upper and lower switches is always on . Applying this constraint yields 25 different space vectors, which are mapped into two concentric decagons with ten equal sectors in the αβ and xy sequence planes. Each sector has two active-large vectors, two active-small vectors, and a null vector. Moreover, the active-large vectors in the αβ plane are active-small vectors in the xy plane, and vice versa. In the proposed scheme, the ampere-second concept is utilized to determine the ratio between the dwelling times of the large and small vectors such that the xy current components are nullified, the utilization of the input dc-current is maximized, and the switching transitions are minimized, which, in turn, minimizes the CSC switching losses. The proposed scheme can effectively provide sinusoidal converter currents, which is suitable for motor drives and energy conversion applications. The proposed scheme is verified using a 1-kW prototype five-phase induction motor fed by a five-phase CSC.