采用磁电自供能的能量储存和电源管理电路研究

Study on the power storage and management circuit of a magnetoelectric self-powered harvester

普通Fe-Ni/PZT磁电复合结构将电磁能转化为电能时输出低,无法驱动无线传感器工作,本文设计了一种更高磁电电压系数的H型音叉式磁电复合结构。论文详细介绍了该结构的工作原理和磁电输出特性。在强度为0.2Oe的交变磁场激励下,该磁电复合结构能够把容量为1.5F的超级电容充电至0.5V。为有效利用超级电容中的电量,本文提出了一种能够提高超级电容输出功率的电能瞬间放电电路。实验结果表明,当超级电容电压为0.5V左右时,在间隙脉冲串(Burst)触发信号频率为30kHz、占空比为75%的条件下,该电路最大放电功率可达120mW,放电时间持续620ms,能够驱动无线传感器在一个发射周期内正常工作。

Since ordinary Fe-Ni/PZT magnetoelectric composite structure has a low output for converting electromagnetic energy into electric energy and its output power is not sufficient for the power requirement of a wireless sensor, an H-type composite structure with higher magnetoelectric voltage coefficient is proposed. The composite structure principle and its performance are introduced in detail. The voltage across a 1.5 F super capacitor can be charged to 0.5 V under the excitation of an AC magnetic intensity of 0.2 Oe. In order to use the output power from the super capacitor efficiently, an instantaneous discharging circuit is designed. Experimental results show that the discharging power of the proposed circuit reaches 120 mW and the discharge time can last for 620 ms for the triggering signal with a frequency of 30 kHz and a duty cycle of 75%. Thus this circuit can meet the wireless sensor power requirement in a transmission cycle time.