MPC Design for SPS Modulated DAB Converters: Impact of Nonlinear Models on Reactive Power Minimization

ABSTRACTThis paper presents the design and implementation of a model predictive control (MPC) framework for single phase shift (SPS) modulated dual active bridge (DAB) converters, focused on reactive power minimization and precise reference voltage tracking, under input voltage and load disturbances. To investigate the impact of model selection in MPC design, this study compares two control strategies: one based on a linearized model and the other on a nonlinear model of the DAB converter. The nonlinear model is derived using a Fourier series representation of the converter's switching dynamics, while the linear model is obtained by linearizing the nonlinear formulation around a nominal operating point. The controller employs the SPS‐based modulation and adjusts the phase shift between the switches on the primary and secondary sides to stabilize the output voltage while minimizing the reactive power exchange. Experimental results demonstrate that the nonlinear MPC achieves superior dynamic performance, reducing overshoot from 5.1% to 1.8%, and settling time from 2.3 ms to 1.1 ms even under 25% load disturbance. Motivated by these results, a hybrid control strategy is proposed, in which the controller dynamically switches between the linear and nonlinear models based on the operating conditions. During normal operation, the linear model is employed to reduce computational burden while maintaining acceptable performance. When input or load disturbances occur, the controller transitions to the nonlinear model to exploit its higher accuracy. The results confirm the effectiveness of the proposed control strategy in balancing performance and computational efficiency.