Integration of DG Units to Hybrid Microgrid with Power Balancing Control Using CHB Multilevel Inverter under Various Loads

In This Paper proposes a Hybrid H-bridge (CHB) multilevel grid to reduce the processes of multiple dc-ac-dc or ac-dc-ac conversions in an individual ac or dc grid. The H-bridge (CHB) multilevel grid consists of both ac and dc networks connected together by multi-bidirectional CHB multilevel converters. AC sources and loads are connected to the ac network whereas dc sources and loads are tied to the dc network. Energy storage systems can be connected to dc or ac links. The CHB multilevel inverters increase the output voltage level and enhance power quality. The HPS employs fuel cell (FC) and photovoltaic sources as the main and super-capacitors as the complementary power sources. Fast transient response, high performance, high power density, and low FC fuel consumption are the main advantages of the proposed HPS system. The proposed control strategy consists of a power management unit for the HPS system and a voltage controller for the CHB multilevel inverter. Each distributed generation unit employs a multi proportional resonant controller to regulate the buses voltages even when the loads are unbalanced and/or nonlinear. The proposed H-bridge (CHB) multilevel grid can operate in a grid-tied or autonomous mode. The coordination control algorithms are proposed for smooth power transfer between ac and dc links and for stable system operation under various generation and load conditions. This H-bridge (CHB) multilevel grid system operates under normal conditions which include normal room temperature in the case of solar energy and normal PV ,FC, MTG, BES and SC speed at plain area in the case of PV ,FC, MTG, BES and SC energy. The Power Balancing Control simulation results are presented to illustrate the operating principle, feasibility and reliability of H-bridge (CHB) multilevel grid proposed system. Index Terms - Cascaded H-bridge (CHB) multilevel inverter,fuel cell (FC), hybrid power source (HPS), multiproportional resonant (multi-PR), photovoltaic (PV), Fuel cell (FC) ,Micro turbine generator (MTG), Battery (BES) and, super capacitor (SC).