High‐efficiency design method of LLC resonant converter for PHEV battery chargers (based on time‐domain model)

Abstract

High efficiency, high power density and wide output voltage are required for on-board charger (OBC) applications. LLC resonant converter has the advantage of achieving zero-voltage switching for variable frequency and different load conditions. Compared with conventional fundamental harmonic approximation method, operation-mode analysis based on the time domain model provides an accurate description of resonant current, voltage and DC gain. In this study, the efficiencyoriented modified method is proposed based on the operation-mode analysis. The converter inductance ratio, characteristic impedance and transformer turns ratio are optimised and both-side soft switching can be achieved in the high output voltage region. Conduction loss can be minimised by optimising resonant parameters. Finally, a high-efficiency design method is proposed and validated through experiments on a 3.3 kW prototype applied in OBC. The prototype of the LLC resonant converter has been tested for dynamic charging voltage (230-430 V) with a peak efficiency value of 98.5%.

Design of Combined Stationary and Mobile Battery Energy Storage Systems

“…ℎ Efficiency of the Charger (%) -used when calculating the power absorbed from RES into BESS 95 [39] Efficiency of the Inverter (%) -used when calculating the power provided into AC applications 95 [39] Weighted Annual Cost of Capital (%) 5.25 [26] The price for energy provided to EVCSs ($/MWh) [Assumed] 100…”

A new detailed loss model and design approach for LLC resonant converter with phase shift control to overall optimization of converter loss at whole battery charging process

“…Many researchers have worked in the field of resonant converter design. In earlier research, [10][11][12][13] LLC resonant converter has been designed based on the various operation modes. In this method, the operation modes boundaries are obtained from the precise time domain model.…”