Four wire single-phase to three-phase system for rural distribution network

This work presents the experimental development of a four-wire single-phase to three-phase static converter for rural distribution system. The converter topology is based on a front-end full-controlled PWM rectifier that handles the DC bus voltage regulation as well as improves the input power factor correction. In order to provide the three-phase four-wire system, a four-legged PWM voltage source inverter (VSI) is used at the output. The rectifier-inverter control strategy has been implemented in a digital processor (DSP), where a proposed PLL algorithm performs the rectifier synchronism. Component specification guidelines and control strategies are described. Complete models are implemented in an electromagnetic transient simulation package (PSCAD/EMTDC™), where the converter is connected to a rural distribution network and is supplying three-phase and single-phase loads. Simulation results show that this converter can ride through a typical voltage sag condition that is very often in rural areas. The converter topology is composed of 12 IGBTs and can be implemented by two off-the-shelf three-phase PWM inverters. This availability can offer significant cost reduction. Experimental results are provided.