大功率直流系统六相磁耦合非隔离型双向DC-DC变流器研究

针对大功率电力电子系统对高效率、高功率密度、高可靠性双向变流器的需求,采用交错并联磁集成技术,深入研究了适用于大功率系统的六相交错型非隔离全耦合双向功率变换器,同时研究了适用于该变换器的、具备多自由度可变耦合度的阵列式对称化六相耦合电感器。首次提出了可实现六通道变换器主电感之间对称化全耦合的磁集成理论;通过对主电感全耦合理论和变换器的工作模态的详述分析,推导了不同占空比区间下静态及动态等效电感,采用归一化的处理方法,给出最佳耦合系数设计准则,并同时给出了通用扩展型阵列式耦合磁件的设计方法;最后通过仿真和实验,对采用非耦合与全耦合电感的变换器进行性能对比测试,证明了理论分析的正确性。六相非隔离磁耦合技术能够降低每个通道的电流应力、增大功率输出容量、降低总电压电流纹波,并同时改善变换器每相电流纹波和动态响应特性,进一步提高功率密度,更适用于大功率直流变换系统。

Research on Six-phase Magnetic Integrated Bidirectional DC-DC Converter for High Power Direct Current System

According to the demand of high efficiency, high power density and high reliability of the bidirectional converter of high power DC power converter system,the interleaving magnetics expansion theory is adopted in this paper to study in-depth the six interleaved typen on isolated full coupled bi-directional power converterusing for large power system. At the same time,an arrayed symmetric six-phase coupled inductor with multiple degrees of freedom and variable coupling is proposed for the converter. For the first time, the magnetic integration theory is proposed to realize the symmetric full coupling among the main inductors of the six-channel converter. Based on the detailed analysis of the theory of the main inductor full coupling and the working mode of the converter, the static and dynamic equivalent inductances under different duty cycle are deduced, and then, the optimal coupling coefficient design criteria is set by using the normalized processing method, and the design method of the universal extended array type coupling magnet is given. Finally, the performance comparison of the inverter with uncoupled and fully coupled inductance is given to prove the correctness of the theoretical analysis by simulation and experiment. The results show that the six-phase non-isolated magnetic coupling technology can reduce the current stress of each channel, increase the power output capacity, reduce the total voltage and current ripple, at the same time, improve the converter current ripple and dynamic response characteristics, and further improve the power density, which is more suitable for high-power DC conversion system.