Improving Power Quality in Hybrid PV - Wind Operated Standalone System with Dual Inverters by Using TSK Fuzzy Controllers

Supplying electrical power to consumers through renewable energy sources based hybrid standalone systems is a best choice to reduce global warming instead of using diesel generators in isolated locations worldwide. Moreover, standalone hybrid power supply systems are also becoming popular in many urban areas including hospitals, universities, institutions, small scale industries and agriculture fields due to their features. Generally a storage device is required to achieve power balance between generation and load since both are randomly varying in such kinds of power supply systems. Hence a battery bank is included in the hybrid standalone system which is designed by Photovoltaic (PV) and PMSG based wind power generation system. In order to supply quality power to consumers, effective control coordination is required among all components in the system. Moreover, single generation systems of PV and wind cannot maintain load demand in high power systems. Therefore multiple PV and wind systems are considered in this paper for connecting at common dc-link to meet the load demand. Further an inverter is connected between dc-link and AC loads. Hence, the system can have the facility of both dc and AC microgrids to operate both kinds of loads. Under this scenario, constant voltage at both dc-link and AC load bus should be supplied to maintain the power quality in the system. Hence, a novel control technique is implemented in this paper for supplying quality power to both dc and AC loads. However, conventional PI controllers are unable to produce accurate output under rapid changes in input. Therefore, Takagi Sugeno Kang (TSK) Fuzzy controllers are adopted in proposed control schemes. Two inverters are considered in this paper, one is connected between dc-link and AC loads and another is in between AC load bus and battery system. Moreover a bidirectional dc-dc converter is incorporated between battery bank and inverter to maintain power balance. In this configuration, the inverter between battery system and AC load bus can also acts as inter line power flow controller. In order to present the responses similar to real time, the Hardware-in the-Loop (HIL) is implemented with the help of OPAL-RT modules.