THREE-PHASE COMPENSATOR FOR LOAD BALANCING AND REACTIVE POWER COMPENSATION IN THREE-PHASE, FOUR-WIRE ELECTRIC POWER DISTRIBUTION SYSTEMS

摘要

This paper deals with a three-phase active power compensator (APC) to compensate reactive power and to balance unbalanced loads in the three-phase four-wire electric power distribution system. An APC is realized employing three single phase IGBT based VSI bridges with a common dc bus capacitor. Reference supply currents are estimated using P-I control over the average dc bus voltage and three-phase supply voltages. APC reference currents are derived from reference supply currents and load currents. A hysteresis rule based carrierless PWM current control is used over compensating currents of the APC and its derived reference currents. Simulated performance of the APC for the single phase, two-phase and three-phase lagging power-factor loads is illustrated to demonstrate the reactive power compensation and load balancing features of the APC.