一种输出并联型CLTCL多谐振软开关直流变换器

A Parallel-Output CLTCL Multi-Element Resonant Soft-Switching DC-DC Converter

提出一种输出并联型CLTCL多谐振软开关直流变换器拓扑,采用双变压器结构且高频变压器二次侧并联,谐振腔内包含多个电容、电感谐振元件。通过合理参数设计,变换器在额定工况下能够同时传递基波和3次谐波有功功率,提高谐振电流利用率,保证较高效率变换,在狭窄的频率范围内实现直流电压增益宽范围可调。功率开关管具有零电压开通(ZVS),二极管同时实现开通、关断过程的零电流软开关(ZCS)或近似零电流,开关损耗得到抑制。双高频变压器的漏感均被相应串联谐振电感吸收,参与谐振过程,寄生参数给电路带来的不利影响被成功削弱。本文基于一台500W的样机进行实验验证,结果表明变换器能够在较宽的负载范围内获得接近95%的较高效率,最高效率点为95.4%;在额定点附近20%的频率范围内实现电压增益从半额定值至额定值可调的有益效果。

In this paper,a novel parallel-output type CLTCL multi-element resonant softswitching DC-DC converter is proposed.It employs the dual transformers architecture,whose secondary sides are connected in parallel.The resonant tank contains multiple resonant components of capacitors and inductors.Through appropriate parameter design,the converter can transmit the fundamental and 3rd harmonic active power simultaneously,increasing the utilization of the resonant current and ensuring high efficiency conversion.Widely adjustable range of DC voltage gain is also achieved within a narrow frequency range.Besides,all the power switching devices have obtained the turn-on zero-voltage soft-switching(ZVS),and all the diodes realize the turn-on and turn-off zero-current soft-switching(ZCS)or quasi-soft-switching.The leakage inductance of the dual transformers is absorbed by the corresponding series resonant inductor.They also participate in the resonance process,which weakens the adverse effects of the parasitic parameters on the circuit.To verify the feasibility of the circuit design,a 500W prototype is tested.The proposed converter can achieve high efficiency of nearly 95%over a wide load range with a maximum efficiency point of 95.4%.The voltage gain is adjustable from half rating value to the rating value in the frequency range of 20%near the rating point.