Pulse area modulation control implementation for single-phase current source-fed inverter for solar photovoltaic power conditioner

Single-phase current-fed PWM inverter using IGBTs has some unique advantages for small scale distributed utility-interactive power supply system as compared with voltage-fed PWM inverter. In particular, this is more suitable and acceptable for a nonisolated type utility-interactive power conditioner, which is going to be widely used for residential solar photovoltaic power generation (PVG) system in Japan. In practice, this current-fed PWM inverter has a significant disadvantage. The output current of this inverter includes large harmonic contents when the inductance of smoothing reactor in its DC side is not large enough to eliminate its current ripple components of this inverter. In order to overcome this problem, a new conceptual pulse area modulation scheme of this inverter is introduced as an alternative scheme of conventional PWM. This paper presents a new effective control implementation of used as a novel PVG conditioner using current-fed inverter which is able to reduce the harmonic contents in the output current produced by the single-phase current-fed pulse area modulated inverter even when the ripple current in its smoothing DC reactor is sufficiently downsizing. The basic operating principle of the proposed control strategy for this inverter type PV conditioner system is described, and its simulation results to confirm this operation are discussed and evaluated herein.