Design Elements of a Nonlinear Decentralized Control Scheme For Modular Power Conversion

Modularity is an effective way to increase power converter capacity without increasing individual device stress. Its most significant impediment is control. Decentralized control of modular converters is preferable to centralized and distributed approaches because it scales more easily to large numbers of modules and it reduces the opportunity for global system failure. In this paper, we investigate a decentralized control approach wherein the increment or decrement of each module's power at any time instant depends on the currently processing power. We highlight some issues appearing in experiments that are not seen in ideal theoretical analysis/simulation and propose solutions which are verified with experiments. We demonstrate the proposed control in a variety of configurations, including input-parallel-output-parallel, input-series-output-parallel, and a mixed input-series-parallel-output-parallel arrangement.