石英晶振的储能特性

针对微弱环境能量难以直接快速存储的问题, 采用石英晶振作为储能元件设计了一种高效储能瞬放电路. 石英晶振的高品质因数特性使其能在较小的输入电压下产生剧烈的机械振动, 从而将微弱的电能转换成机械能存储在石英晶振中. 通过对石英晶振的储能原理与能量释放特性进行理论分析, 推导出石英晶振充放电过程中输出电压与时间的关系式, 以及石英晶振释放能量时最大瞬时输出功率与负载的关系式. 并对石英晶振的储能特性进行了实验验证. 结果表明: 实验与理论相符, 且在输入电压幅值为100 mV, 谐振频率f=1 MHz石英晶振的条件下, 石英晶振的储能效率可以达到77%, 能量释放效率为71.4%.

Characteristics of quartz crystal energy storage

As the weak ambient energy is hard to be stored directly and rapidly and unable to drive the electronic load into working properly, a high-efficiency energy storage circuit, with quartz crystal serving as a storage element, is presented. When an alternating electric field is applied to it, the quartz crystal will generate mechanical oscillations of a certain frequency. Since the quartz crystal possesses a high quality factor, in the piezoelectric crystal plate there appears a severe mechanical resonance with a small excitation voltage. In the resonant condition, the external weak electrical energy can be converted into mechanical energy stored in the quartz crystal. The principles of quartz crystal energy storage and instantaneous energy discharge are theoretically analyzed. The relationships between the output voltage and the time and between the maximum instantaneous output power and the load in the processes of quartz crystal charging and discharging are deduced, respectively. The storage characteristics of the quartz crystal are investigated experimentally. The experimental results show a good accordance with the theoretical analysis. A quartz crystal of 1 MHz resonant frequency is adopted in this research. When the input voltage amplitude of the energy storage circuit is 100 mV, the optimal matching load is 820 Ω and the maximum instantaneous output power of quartz crystal discharging circuit is 150 μW. The storage efficiency and the release efficiency of the quartz crystal can reach up to 77% and 71.4% respectively. These results provide evidence for quartz crystal energy storage in the condition of weak ambient energy.