Continuous-Control-Set Model Predictive Control-based Energy Routing with Over/Under Voltage Protection

Multi-active-bridge (MAB) converters are highly promising as energy routers in renewable energy applications. Their multiple-input multiple-output (MIMO) control challenges can be effectively addressed by a model predictive control (MPC) approach, which minimizes the interference between different ports and simplifies the controller design. However, during the optimization process, the input and output constraints are usually ignored to simplify the implementation, which may degrade the control performance and lead to large voltage overshoot/undershoot when the constraints are violated. Meanwhile, solving the constrained MPC problem within a short sampling time poses a huge computational challenge. To address these issues, in this article a continuous-control-set model predictive control (CCS-MPC) scheme is developed for the MAB converters, which incorporates input and output constraints to achieve over/under voltage protection. A MPC problem with multiple constraints is formulated and converted into a quadratic programming (QP) problem. Its real-time implementation on a low-cost microcontroller unit (MCU) is further discussed including QP solver deployment, real-time certification, and delay compensation. Finally, the developed CCS-MPC scheme is experimentally verified by a four-port 500 W energy router prototype and well demonstrates the over/under voltage protection capability.