Design Space Optimization of a Three-Phase LCL Filter for Electric Vehicle Ultra-Fast Battery Charging

State-of-the-art ultra-fast battery chargers for electric vehicles simultaneously require high efficiency and power density, leading to a challenging converter design. In particular, the grid-side filter, which ensures sinusoidal current absorption with low pulse-width modulation (PWM) harmonic content, can be major contributor overall size losses. Therefore, this paper proposes complete analysis, design optimization procedure of three-phase LCL filter modular DC fast charger. First, an overview basic modeling is provided most significant system transfer functions are identified. Then, optimal ratio between converter-side inductance discussed, aiming maximum filtering performance. A novel methodology, based on graphical representation space, thus proposed. Specifically, several constraints elements enforced, such that all feasible parameter combinations since in low-voltage high-power applications inductive components typically dominate volume, loss cost, viable minimizes total required selected. The proposed applied 30 kW, 20 kHz 3-level unidirectional rectifier, employed performance selected design, featuring equal 175 ??H inductors 15 ??F capacitors, verified experimentally active front-end prototype, both terms attenuation capability control dynamics. distortion (THD) 1.2% achieved at full load generated harmonics comply applicable standard. Moreover, separate tests performed different values grid inner impedance, verifying stability various operating conditions supporting general validity methodology.