Fully masterless control of parallel converter

In this article a fully decentralized modular approach (real masterless) for parallel converter control is presented. A control circuit assigned to each switching cell, communicating with its neighboring circuits, is presented in detail. It is able to provide the computation of the common mode duty cycle, the balancing of the leg currents and the proper phase shift for the interleaved carriers of the converter in a decentralized manner. The identical control circuits are connected together in a daisy-chain configuration. Then, the implementation of a converter using a large number of parallel legs (ten to hundred) becomes easy. It works regardless of the number of legs and provides the ability to add or remove dynamically a leg easily. In order to help the designer, a stability study for the current sharing loop is provided. A test board demonstrates the validity of the solution. Moreover it shows that, using this modular control approach, a leg of the converter can be added or removed dynamically without any additional control consideration.