Control of parallel operated inverters

A Distributed Power System (DPS) which consists of two Uninterruptible Power Supplies (UPS) system is investigated. The focus of work is on the inverter control stages. A key feature of the control scheme is that it uses only those variables which are locally measured at the inverter. So there is no need of communication between the inverters. Real and reactive power sharing between the inverters is achieved by controlling two independent parameters at the inverter- the power angle and the fundamental inverter voltage magnitude. The control algorithm makes sure that the total load is shared between the supplies in accordance with their rated power levels and the frequency of the supplies are restored to the rated values after the transition. Simulations are performed in MATLAB SIMULINK environment with Sine PWM control and Space Vector PWM control.