Flexible Multi-Battery System With Active Balancing and Voltage Regulation

This paper presents a flexible multi-battery system with active balancing and voltage regulation. The presented battery system has two main features: (1) active balancing can be achieved between batteries connected in series/parallel using a balancing converter, and (2) the presented battery system can operate with a smaller number of batteries while still achieving balancing between the operating (existing) batteries and regulating the load voltage using the balancing converter. These features make the presented system suitable for applications where energy supply continuity is highly desired. The operation principle of the flexible battery system is presented in detail. A comprehensive steady-state analysis and voltage balancing control diagrams are presented for different operating scenarios. Moreover, expressions for the balancing converter inductor currents and batteries currents are derived to provide insights on the system’s operation, and to show how the balanced condition is achieved under different operating scenarios. Experimental results obtained from a laboratory prototype are presented to evaluate the features of the battery system.