Fractional-Order Terminal Sliding Mode Control Based Model Predictive Control of Totem-Pole PFC for EV Charging Applications

This article proposes an advanced control strategy for a totem-pole bridgeless boost power factor correction (TPB-PFC) converter, combining fractional-order terminal sliding mode controller (FOTSMC) in the outer voltage control loop with model predictive control (MPC) in the inner current control loop. Traditional PFC converters use cascaded proportional–integral controllers, which struggle with performance under disturbances due to their linear nature. While sliding mode control (SMC) offers improved robustness, its application in voltage regulation is limited by bandwidth constraints. To address these challenges, a more continuous FOTSMC is proposed that enhances dynamic performance and robustness by introducing fractional-order dynamics and disturbance rejection features. The MPC ensures optimal switching decisions, further improving efficiency and transient response. In addition, expanding the bandwidth of the voltage controller may not sufficiently cancel out the double frequency component contained in the output voltage, causing this component to affect the current reference and ultimately induce third harmonic distortion in the input current. To prevent these issues, a moving average filter is used to remove the double frequency component from the output voltage, thereby suppressing the harmonic distortion in the input current. The combined control framework is validated through experiments under various test cases.