用于低能量密度换能器的电源管理电路

Power management circuit for the low energy density transducer

为无线微传感器供能的低能量密度压电换能器,其采集能量少、输出功率低。使用传统的电源管理电路向储能电容充电时,低功率地能量传输使得采集能量大多耗散在整流电路中,而最终能够传递给储能电容的较少,导致电路充电功率低下。为解决低能量密度条件下,电源管理电路整流耗能大、充电功率低的问题,引入了高品质因数的石英晶体,提出一种新式电源管理电路。电路使用石英晶体低损耗地聚集换能器采集到的能量,当能量聚集到一定水平后,快速释放能量,为整流电路提供较高的输入功率,降低耗散在整流电路中的能量的比例,从而使更多的能量传递给储能电容,使其获得较高的充电功率。实验表明,对于50 Hz频率下输出8 V的压电换能器,相比于传统变频匹配电源管理电路,所提电路可将充电电压提高163%,充电功率提高110%。

For a low energy density piezoelectric transducer which powers wireless micro-sensors,it harvests little energy,and its output voltage is low.When the storage capacitor is charged by conventional management circuit,the energy transmission in low power leads to a high proportion of harvested energy dissipated in rectifying circuit,and little energy is transferred to the storage capacitor,which means low charging power.To overcome the large power dissipation and low charging power issues in low energy density environment,a novel management circuit is proposed,which involves quartz crystals with the high quality factor.The circuit uses quartz crystals to accumulate the harvested energy in little consumption.When the energy stored in the quartz crystal is high enough,it is released quickly,and then a higher input power is produced for the rectification circuit,which can reduce the proportion of energy dissipated in rectifying circuit.Hence,more energy is transferred to the storage capacitor,and a larger charging power can be obtained.Experiments show that for a piezoelectric transducer which harvests 50 Hz energy and produces 8 V voltage,the proposed circuit can improve the charging voltage and the charging power by 163% and 110% respectively,compared with the management circuit just using frequency-conversion matching technique.