Controller Design and Modelling of a Single-Switch Fifth-Order High Voltage Gain Converter with Parasitics for Electric Vehicle Charging

High gain charging of electric vehicles (EVs) has become an important research topic in recent years. This paper proposes a fifth-order combination of inductor, capacitor and diode (L-C-D cell) based nonideal quasi-Z-source boost converter (QZSBC) for charging electric vehicles (EVs). It is derived from a conventional Z-source converter, and features a single-switch structure, a shared ground between load and source, low voltage stress on capacitors, and achieves high voltage gains. Detailed examination involving steady-state and small-signal models is formulated, investigating various performance aspects. A fixed frequency indirect integral sliding mode controller (FFIISMC) is employed to design a robust controller to mitigate the disturbances in the presence of uncertainties. The controller design comprises a Duty-Ratio Feedforward Control Unit to reduce controller burden and a sliding function-based feedback unit for stability. A surface includes direct and indirect mode control for better stability and response under FFIISMC. Compared with existing voltage/current mode control, the proposed controller can achieve lower current ripple and better stability for QZSBC when load and line disturbances are significantly high. MATLAB simulations confirm the controller's performance in achieving regulation objectives. TMS320F28379D DSP board is used for controller implementation and 240W QZSBC prototype is developed for experimental verifications.