基于半桥谐振拓扑的高效高密度兆赫兹RDCX变换器研究

Research on MHz RDCX Converter with High Efficiency and High Power Density Based on Half-bridge Resonant Topology

谐振变换器因其软开关特性,很容易实现MHz的开关频率,满足高密度供电模块的效率和密度要求。但是MHz高频谐振拓扑采用调频控制方式存在软开关范围受限的问题。当谐振变换器工作在直流变压器DCX(DC transformer)时才能充分发挥其高效率高功率密度的优势,但是失去了电压调控能力。因此通过在DCX中串联可控电压源的方式实现可调直流变压器RDCX(regulated DCX)。绝大部分输入功率直接通过DCX处理,仅通过小部分输入功率的两级处理实现输出电压调节,保证了电路的高效率和高功率密度优势。详细设计了输入电压为360~400 V,输出电压为12 V,满载功率为750 W的RDCX样机参数,通过实验验证了该RDCX方案的优越性。

A resonant converter can easily operate at MHz frequency owing to its soft-switching characteristics,which can meet the requirements of efficiency and density for a high-density power supply module.However,the soft-switching range of the resonant topology will be limited if the frequency modulation methods are adopted in the MHz condition.The resonant converter can give full play to its advantages of high efficiency and high power density only when it operates as a DC transformer(DCX),which is nevertheless at the cost of losing its voltage regulation capability.As a result,a regulated DCX(RDCX)is achieved in this paper by a controllable voltage source cascading in the DCX.Most of the input power is directly processed by the DCX,while only a small part is processed by a two-stage structure to achieve output voltage regulation,thereby ensuring the circuit’s high efficiency and high power density.An RDCX prototype with input voltage of 360~400 V,output voltage of 12 V and full-load power of 750 W was designed in detail,and experimental results verified its advantages.