Parameter Design of CLLC Converter Based on Resonant Cavity Current Optimization

Abstract

Abstract:

CLLC converters are widely used in new energy power conversion systems because of their wide voltage gain range and easy realization of soft switching. However, the fundamental wave approximation method widely used in its design has the relatively large errors when it is far away from the resonant point. Therefore, a parameter design method of CLLC converter based on the time domain model is proposed from the perspective of resonant cavity current optimization. Firstly, the voltage gain of the converter and the current characteristics of the resonant cavity are analyzed based on the time domain model, and a constraint function of characteristic impedance and resonant current is proposed. Then, the parameter design domain is obtained with the domain using the constraining the gain, mode boundary and zero voltage switching(ZVS)condition, and the optimal design point is obtained with the domain using the constraint function. Finally, a 1 kW prototype is designed to verify the feasibility of the proposed method, and the peak efficiency of the prototype reaches 97.48%.

Key words: CLLC converter, time domain model, resonant current, efficiency optimization

CLC Number:

TM46

LI Shimao, HUANG Xiaosheng, SHEN Kun, LIN Shuyi. Parameter Design of CLLC Converter Based on Resonant Cavity Current Optimization[J]. LOW VOLTAGE APPARATUS, 2025, 0(4): 31-40.

Figures/Tables 20

References 15

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模式边界	约束条件
OPO/PO	u_{mn_P}(0)-u_{2n_P}(0)=M
PO/PON	u_{mn_O}(θ_O)-u_{2n_O}(θ_O)=-M
NP/NOP	u_{mn_N}(θ_N)-u_{2n_N}(θ_N)=M

设计点	参数(k,Z_r/Ω)	L_rp、L_m/μH	I_p、I_s电流有效值/A
优化点a	0.235, 26.50	21.10, 89.74	4.804,3.460
对比点1	0.350, 26.50	21.10, 60.29	6.116,3.510
对比点2	0.350, 80.00	63.60, 181.89	3.387,3.451
基于FHA 设计	0.740, 92.08	73.27, 98.90	4.810,4.020

参数	计算值	实际值
电感比k	0.235	0.239
特征阻抗Z_r/Ω	26.50	26.44
一次侧谐振电感L_p/μH	21.10	21.37
一次侧谐振电容C_p/nF	30.00	30.57
励磁电感L_m/μH	89.80	89.26
二次侧谐振电感L_s/μH	14.70	15.08
二次侧谐振电容C_s/nF	43.06	42.93