Loss Modulated Deadbeat Control for Grid Connected Inverter System

Abstract

Deadbeat controllers are commonly employed in grid connected inverter systems for their fast transient response. In this paper, a loss modulated deadbeat current control (DCC) is proposed for a grid connected inverter system. This control calculates the required modulation signal by considering the losses in the system at every switching cycle. The proposed method tracks the reference current with negligible error. The loss component used in the control method eliminates the effect of sensing and computational time delay and adapts to variation in system parameter. The proposed DCC is extended for deadbeat based direct power control (DDPC) without employing inner current control loop. Further, a modified DDPC is presented to eliminate the delay of one switching cycle which is inherently present for the grid current in DCC. The proposed control concepts are realized on a multi-source fed switched capacitor based multilevel inverter. The topology considered features more number of voltage levels with less component count, high gain, self capacitor charge balancing and increased source utilization. The steady-state and transient behaviour of the control methods are verified in simulation and experimental studies for a power rating of 500 W under various system conditions. The proposed algorithms are able to track the reference signals with fast transient response and negligible steady-state error.