Finite Control Set Model Predictive Current Control (FCS-MPCC) of Three-Port Converter for Fuel Cell Hybrid Electric Vehicles

Abstract

Fuel cell hybrid electric vehicles (FCEVs) are considered an appealing option for heavy-duty and long-distance vehicles. However, they require the use of multiple power converters to manage power distribution among the fuel cell, battery or ultracapacitor, and AC motor, leading to increased power losses and a more complex system. To overcome this challenge, multi-port power converters have been proposed to combine two power sources and the AC motor into one conversion stage, boosting overall efficiency and power density in hybrid powertrains. However, these converters still rely on a high number of semiconductors and involve complex control systems. This paper introduces a three-port converter (TPC) for FCHEVs, using only one power stage with 6 semiconductors, achieving high performance control of an ac motor, a fuel cell and a battery. A multivariable optimal control (Finite-Control-Set Model Predictive Current Control) manages the power flows between the energy sources and drives the motor simultaneously. Additionally, the performance of the multiport converter is improved by replacing its three inductors with a custom coupled inductor designed to reduce circulating AC currents. This innovation contributes to improved efficiency and overall functionality of the FCHEV system. The proposed system was validated through an 0.5 kW experimental test bench and simulations of an urban driving cycle. The system controlled the multiple variables of the hybrid system with proper operation and fast dynamics, meanwhile the coupled inductor decreases the current magnitude in 20% compared to the non-coupled configuration.