液态金属磁流体发电系统低电压高变比能量收集电路设计

Design of Low-Voltage High-Transformation Ratio Energy Harvesting Circuit of Liquid Metal Magnetohydrodynamic Generation System

液态金属磁流体(Liquid Metal Magnetohydrodynamic,LMMHD)的发电原理为在外力作用下驱使液态金属切割磁场进行发电,具有输出电流大、电压低且输出易受负载特性影响的特点,因此能量收集很困难。为了解决这一问题,分析LMMHD发电系统的电源特性,提出了基于Boost变换器的能量收集方案,并通过状态空间平均法建模分析了Boost变换器的输入及输出阻抗特性,验证了Boost变换器对于LMMHD发电系统的适用性。此外,针对传统锂电池储能电压需求,提出了应用并联交错型Boost变换器和基于二极管-电容组合结构的Boost变换器的电能收集方案。最后,参考具体的LMMHD发电系统设计了对应的能量收集电路,并通过Matlab仿真验证了设计的合理性。仿真结果表明,改进型Boost变换器实现了20倍高变比升压,实现了50 W、4 V的功率输出。

The principle of Liquid Metal Magnetohydrodynamic(LMMHD)power generation is that driving liquid metal cutting magnetic field to generate electricity under external force. Energy harvesting is difficult for LMMHD because of its large output current,low voltage,and output susceptible to load characteristics. To solve this problem,the power characteristics of the LMMHD power generation system are analyzed first,and an energy harvesting scheme based on Boost converters is proposed. The input and output impedance characteristics of the Boost converter were modeled and analyzed by state space averaging method,and the applicability of the Boost converter to the LMMHD power generation system was verified. In addition,in order to meet the energy storage voltage requirements of traditional lithium batteries,an energy collection scheme using a parallel interleaved Boost converter and a boost converter based on a diode-capacitor combination structure is proposed. Finally,the corresponding energy harvesting circuit was designed with reference to the specific LMMHD power generation system,and the rationality of the design was verified by Matlab simulation. Simulation results show that the improved Boost converter achieves a 20-fold high transformation ratio boost,and achieves 50 W,4 V power output.