Reduction of Power Fluctuation for Grid Connected qZSI-Based Solar Photovoltaic System Using Battery Storage Unit Satyajit Saha, Pritam Kumar Gayen, and Indranil Kushary Abstract In recent years, solar energy conversion system is adopting quasi Z-source inverter (qZSI) for connecting solar photovoltaic array to AC grid. But, output power of solar photovoltaic array is always of fluctuating profile. When this fluctuating power is injected into local grid or micro-grid, voltage at point of common coupling (PCC) experiences a flickering effect. This is an undesired impact on the local grid from the local consumer’s point of view as it affects the performance of electrical gadgets as well as it creates irritation to people’s eyes through illuminating devices. Sometimes, voltage flicker violates the permissible limit, which is specified in grid code. Therefore, this paper provides the solution to mitigate objectionable power quality issue in respect of local grid-connected qZSI-based solar energy conver- sion system. Here, fluctuating power at PCC is reduced by the usage of bidirec- tional converter-based battery storage unit. The charging and discharging operation of battery counteracts fluctuating power profile, hence it significantly smoothens out power profile at PCC and thus, the voltage fluctuation problem at the point can be avoided. The whole study of this paper is done using MATLAB-SIMULINK software. Keywords Battery storage unit · Local AC grid · Quasi Z-source inverter · Solar energy conversion system · Power fluctuation 1 Introduction In recent time, quasi Z-source inverter [1–4] is widely used for converting DC power output of solar photovoltaic array into AC power. This inverter has the following various advantages over traditional voltage source inverter: S. Saha · P. K. Gayen · I. Kushary (B ) Kalyani Government Engineering College, Kalyani, Nadia, West Bengal, India I. Kushary JIS College of Engineering, Kalyani, Nadia, West Bengal, India © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2022 S. Dhar et al. (eds.), Advances in Communication, Devices and Networking, Lecture Notes in Electrical Engineering 776, https://doi.org/10.1007/978-981-16-2911-2_37 349