毫瓦级电磁式振动能量收集中低功耗变换技术

Power Converters With Low-power Consumption for Milliwatt-level Electromagnetic Vibration Energy Harvesting

能量收集是保障分布式传感器持续供电的关键。电磁式能量收集为交流输出,且幅值低,输出阻抗高。为了实现能量高效传输和变换,需要高升压比的低功耗AC/DC变换器,并通过阻抗匹配提高传输效率。然而,现有微能量变换的电路效率仅为60%;且无法实现与输出和输入电压解耦的阻抗匹配,功率传输效率低。为了解决以上问题,这里提出采用临界导通模式(BCM)使变换器输入阻抗仅受导通时间控制,利用固定开通时间的控制方法实现阻抗匹配,并给出了在低压、毫瓦级变换下高效功率器件选型标准。构建了基于氮化镓(GaN)HEMT的双Boost单级AC/DC功率变换器,峰值开环变换效率达74.5%,峰值闭环效率达72.3%。

Energy harvesting is the key to ensuring a continuous power supply for distributed sensors.The output of electromagnetic energy harvesting is low amplitude AC power with a high output impedance.To achieve efficient energy transmission and conversion,low-power AC/DC converters with high boost ratios and improving transmission eficiency through impedance matching are required.However,the efficiency of the existing circuits for micro-energy conversion is only 60%.It is impossible to realize impedance matching with decoupling of output and input voltages,and the power transfer efficiency is low.In order to solve the above problems,the boundary conduction mode(BCM)is proposed to adopt so that the input impedance of the converter is only controlled by the conduction time,the control method is used of constant on-time to achieve impedance matching,and the selection criteria is given of high-efficiency power devices under low-voltage,milliwatt-level conversion.The gallium nitride(GaN)HEMT-based dual Boost single-stage AC/DC power converters are designed with a peak open-loop conversion efficiency of 74.5%and a peak closed-loop efficiency of 72.3%.