Optimal Control for Large Classes of Systems: Bang-Ride Policies and Their Applications

Fast charging lithium-ion batteries are crucial for electric vehicles, but require careful control to avoid overheating and damage. Traditional methods rely on multiple control loops, which can be complex and expensive to implement. In this article, we propose a simpler alternative called selector control systems, which use a single loop with multiple inputs to deliver the required flexibility and performance. By isolating individual control loops, selector systems simplify the overall design and allow for easier tuning.
Selector control systems are commonly used in industrial applications, such as power systems and chemical processes, where safety considerations require limiting variable values within certain limits. Despite their advantages, these systems are often implemented ad-hoc and little is known about their performance in different scenarios. By identifying the problems selector control strategies are best suited for, we can improve their tuning and justify their use in practice.
The article presents a fast-charging problem based on a discretized model of a lithium-ion battery, which maximizes the bulk concentration at the anode while restricting surface concentration and charging current. For this problem, an optimal control problem can be formulated as a linear program, and the solution is shown to be a selector control system. The article also compares the performance of selector control systems with more advanced methods, such as model predictive control, and demonstrates their advantages in terms of ease of implementation and cost-effectiveness.
In conclusion, selector control systems offer a simpler and more efficient alternative to traditional control methods for fast charging lithium-ion batteries. By leveraging the isolation of individual control loops, these systems can improve tuning and reduce complexity, making them an attractive choice for practical applications.