An adaptive control strategy for power balance and the intermittency mitigation in battery-PV energy system at residential DC microgrid level

Abstract

This paper presents the integration of the battery and photovoltaic (PV) system and the adaptive control strategy for power balance and the intermittency mitigation in residential dc microgrid system. The excessive power leads to the overvoltage in the dc bus when available power from PV arrays is greater than the sum of the load power. While clouds pass over the panels, the dc bus becomes dynamically unstable. This paper is proposing the adaptive control strategy in residential dc microgrid to stabilize the dc bus and prevent over-voltage issues. The circuit topology has been selected as a suitable candidate for dc distribution system in residential applications. The implemented circuit topology provides two main dc bus voltage levels for residential applications, 48 V dc, and 400 V dc, and a 100 V dc intermediary bus for power transfer from one bus level to the other. The circuit topology consists of a boost converter for a PV power generation, a buck-boost converter for both discharging and charging the battery from 100 V dc bus, and a bidirectional half-bridge converter to regulate 400 V dc bus. The proposed adaptive control strategy monitors the PV power generation, dc load power demand and optimizes the state of charge (SOC) of the battery in order to constantly balance power generation and the load power demand accordingly. The simulation and experimental results reported in this paper verify the dynamics and performance of the proposed adaptive control strategy for PV-battery system in residential dc microgrid. This control strategy has been implemented and verified in A 2 kW prototype.