A super-twisting enhanced double integral sliding mode direct power control strategy for dual active bridge converters

Abstract

This paper proposes a novel Double-Integral Super-Twisting Direct Power Control (ST-DISMC-DPC) scheme for Dual Active Bridge (DAB) converters. The controller is designed to enhance output voltage regulation under varying load conditions, offering improved robustness and reference tracking compared to conventional PID and standard Double-Integral Sliding Mode Control (DISMC) benchmarks. With a straightforward design that avoids complex modeling and linearization, the ST-DISMC-DPC scheme generates a reference power for direct power control (DPC), computes the phase shift ratio, and achieves fast transient response alongside stable steady-state performance. A rigorous stability analysis of the proposed controller is included to substantiate its theoretical foundation. By incorporating the integral of the voltage error, the controller significantly enhances tracking accuracy and transient mitigation. Quantitative evaluations reveal that the proposed strategy reduces overshoot/undershoot by 56–74% compared to conventional PID and by 6–9% compared to standard DISMC. Furthermore, it achieves substantial reductions in Integral Square Error (ISE) by up to 90% versus PID and up to 13% versus DISMC, while maintaining the fast-settling times characteristic of sliding mode control. Although a marginal increase in steady-state error is observed under extreme load shedding, the absolute deviation remains a negligible 0.05 V (i.e., 0.1% of the 50 V DC bus), underscoring the controller’s excellent practicality. The effectiveness of the approach is validated through its implementation with single-phase-shift (SPS) modulation, initially under fixed-source conditions and subsequently in a PV-battery charging scenario with step irradiance variations. Future work will extend the scheme to address practical challenges such as dead-time effects and DC bias currents in high-frequency transformers, alongside a comprehensive quantitative evaluation of efficiency-related metrics.