Voltage rise suppression and load balancing by PV-PCS with constant dc-capacitor voltage control based strategy on single-phase three-wire distribution feeders

This paper proposes a novel and simple reactive power control strategy and source-side current balancing for photovoltaic (PV) power conditioning system (PCS) to suppress the voltage rise at the point of common coupling (PCC) on single-phase three-wire distribution feeders. The proposed reactive power control and load current balancing use only a constant dc-capacitor voltage control, which is commonly used in the grid-connected inverters. Any calculation blocks of the reactive and unbalanced active components of the load currents are not necessary. Thus, the authors provide the simplest algorithm to suppress the voltage rise at the PCC, balancing the source-side currents. The basic principle of the constant dc-capacitor voltage control based strategy is discussed in detail. A computer simulation is implemented to confirm the validity and high practicability of the proposed control algorithm for PV-PCS using a typical single-phase three-wire distribution feeder model in Japan. Simulation results demonstrate that controlling reactive power on the source side by PV-PCS with the proposed control method suppresses the voltage rise at the PCC, balancing the source-side currents.