Voltage stability in DC micro grid by controlling two battery units with hybrid network systems

Abstract

In DC network systems micro grid battery storage units are used to assist the main source of renewable energy (PV array) in providing stable voltage on the DC bus. Micro grid storage systems play an important role in providing services on demand. The lithium-ion batteries are used in this design, because these batteries have high energy density. In the micro-grid design is used three units of PV arrays and each unit consists of two PV arrays and two batteries. Battery units are used for storage of PV array sources and single phase gird AC. The PV array unit provides 22.8 V output voltage and the battery unit provides 22.78 V output voltage. Boost converter increases the voltage of the PV array and battery unit to a DC bus of 48 V. The PID controller is effectively used boost converter in raising or lowering the voltage. The advantage of using two battery storage systems is that if one unit is not sufficient to provide a voltage to the DC bus, then the battery unit on the AC grid side will also rapidly provide a voltage to the DC bus.