Variables decoupling and multi-objective optimization of all-SiC interleaved boost converters for fuel cell electrical vehicles

Interleaved boost converters (IBCs) are widely used in fuel cell electric vehicles (FCEV) due to the harsh requirement in inner space and the driving mileage. However, the optimal balance between efficiency and power density in IBCs remains elusive. Therefore, a strategy that involves decoupling variables and employs multi-objective optimization techniques is proposed in this paper to tackle this challenge. With variable decoupling, the efficiency and power density are evaluated simultaneously in a comprehensive model composing of three design variables, including the interleaved phase number N, the switching frequency fs, and the magnetic core radius r. Subsequently, iterative calculations are performed within the defined range of the design variables to minimize the weight and volume while adhering to efficiency criteria. During the optimization, to meet the strict ripple requirements in FCEVs, a mathematical model of the inductance and capacitance is deduced from a multi-phase IBC. Finally, a 60 kW all-SiC IBC is multi-objective optimized and constructed. The input current ripple is basically consistent with the theoretical calculation, thereby satisfying the specified design criteria. The power density of the converter can reach 10.78 kW/L and 5.36 kW/kg. The peak efficiency is 98.5%, which is achieved at 22 kW, and the efficiency at 60 kW reaches 97.9%.