Control of a Three Phase Inverter Mimicking Synchronous Machine with Fault Ridethrough Capability

Due to high penetration of renewable energy systems in the distribution grid, it has become an extreme challenge to maintain synchronous stability of the grid. During asymmetrical faults the major challenge is to limit the inverter current and keep it within limits so that the inverter relay does not trip. Such a control methodology ensures seamless power to the consumers without damaging the inverter. In this paper a second order generalized integrator based inverter control operating like a virtual synchronous machine is proposed. The calculations for the inverter control states are performed on a per phase basis and the control algorithm is developed. The dynamic equations describing the proposed control algorithm with its analyses is presented in this paper. Numerical simulations based on MATLAB/Simulink are performed to verify the efficacy of the proposed control technique on a three phase grid connected inverter.