A Direct Modularization Method for Multi-cell to Multi-cell Equalizer With Large Cell Count

A modular voltage equalizer can be used in a wide variety of applications without changing the module design. However, the modularization of an equalizer topology often involves slow intermodule equalization, additional energy loss, and cost. A study on available modularization techniques shows that transformer-based equalizers offer simple and low-cost modularization methods. Conversely, the transformer-less equalizers can offer a more compact design, but their modularization methods suffer from either high complexity and loss, or slow intermodule equalization speed. In this work, one two-winding transformer is introduced into a transformer-less equalizer module to leverage the modularization benefits of transformer isolation while still achieving a more compact design than transformer-based equalizers. The proposed direct modularization method achieves fast intermodule equalization and fixed design for a variety of applications with a small increase in cost and size. The proposed method is implemented on a transformer-less equalizer and its effectiveness is validated experimentally with a three-module prototype.