Modular-three-level buck converter for electrolyzer applications: current control with capacitors voltage balancing control

This paper presents a DC-DC buck converter topology with multi-output capability for stacks of electrolyzers. The converter operation and its behavior are explained through the derivation of differential equations. A control strategy is proposed to regulate the hydrogen production rate effectively. To alleviate the voltage rating requirements of the utilized devices, a series of input capacitors is employed. This configuration reduces the voltage rating burden on individual capacitors by dividing the overall voltage across multiple capacitors. Additionally, a voltage balancing control scheme is introduced to address any potential imbalance in the input capacitor voltages. The proposed converter topology and its controllers are validated through extensive simulations using the circuit-based Simscape tool in MATLAB/Simulink.