Adaptive Predictive-DPC for a Grid Connected Low-Cost PV Generator

Abstract

Pulse-width modulated (PWM) voltage source converters (VSCs) with various control strategies are used as PV inverters. Recently, methods based on predictive control have become of great interest due to various advantages they offer, the main being superior dynamic behavior, simple structure and concepts and ease of implementation and accordance to inherent discrete nature of power electronic converters. In this study, an augmented discrete model for the VSC is derived, based on which, an improved deadbeat-DPC scheme for the grid connected PWM-VSC which utilizes the adaptive observer in its structure is proposed. States and input disturbances are estimated by using full order adaptive observer in next sampling period and then by using the system model, the converter reference voltage is selected so that the power errors become zero in the end of the two next sampling periods. It provides the sensorless operation of the converter by eliminating the filter current sensor, that reduces the inverter cost and helps compensate for uncertainties by one step ahead estimation of parameters and un-modeled dynamics.