Adaptive gain sliding mode control for a totem-pole PFC with EV charger application, meeting the affected grid's power quality constraints

The escalation of power quality issues, driven by the widespread adoption of power electronic devices, mandates compliance with power quality constraints before the grid integration. An inadequately controlled electric vehicle charger system (EVCS) can significantly distort the grid voltage waveform. The controller is responsible for output voltage regulation, power factor correction (PFC), soft zero-crossing, and reducing total harmonic distortion (THD). The totem-pole (TP) PFC converter topology addresses efficiency by eliminating the diode bridge, thereby reducing switching losses. To enhance the PFC control performance, this paper proposes a novel switching function based on the second-order sliding mode control (SSMC). The SSMC offers a superior alternative to the conventional SMC by significantly attenuating the chattering through finite-time convergence via a power rate reaching law. Furthermore, incorporating a hysteresis band around the reference inductor current provides an additional mechanism for the chattering suppression. Simulation results confirm that the proposed switching method complies with the voltage THD of a strong high-inertia grid characterized by a high short circuit ratio (SCR). The validation also verifies a stable PFC operation and a satisfying current THD across various load conditions. • Novel switching function has been defined for precise controlling the slave loop operated as the PFC. • The unity power factor and negligible current THDs were attained due to the controller PFC proper operation. • Chattering was effectively eliminated inasmuch as the reshaped current ripple comply with the hysteresis bounds around the reference current.