被动湍流控制圆柱驰振能量收集的等效电路研究

Equivalent circuit analysis of the galloping-based piezoelectric energy harvester with a passive turbulence control cylinder

为更好的预测驰振压电能量收获机的性能,首先建立了等效电路仿真模型(ECM)并通过实验验证,最大误差不超过10%。采用该方法分析了被动湍流控制(PTC)下圆柱驰振压电能量收集的仿真模型,且该方法可将驰振能量转化系统的质量-弹簧-阻尼(M-C-K)控制方程中各参数用等效电路的电子元件来表示,从而可以分析过往仿真手段所不能解决的直流电路耦合问题。其次,从能量收集效率角度分析了交流-直流等效电路中临界风速(Ucr)随外接载荷的变化规律,及输出电压与功率随不同风速和外界载荷的变化规律。结果表明,交流电路中Ucr随载荷的增大先增大后减小,直流电路中Ucr随载荷的增大逐渐减小。当风速达到Ucr的最大值时,驰振在任一电阻下均会发生。U≥Ucr时,驰振出现锁定现象,输出电压和功率均随着风速的增大而增大。当风速过大时,增长率有减小趋势。输出电压均随着电阻的增大而增大,功率随电阻的增大先增大后减小。相比于交流电路,直流电路的最佳负载由1.1 MΩ提高到2.0 MΩ,同时功率峰值从0.08 mW降低到0.04 mW。

In order to better predict the performance of the galloping piezoelectric energy harvester,an equivalent circuit simulation model(ECM)was established and verified by experiments,with a maximum discrepancy of less than 10%,by which the cylindrical galloping piezoelectric energy collection under passive turbulence control(PTC)was analyzed.The parameters of the mass-spring-damping(M-C-K)galloping control equation for the energy conversion system were expressed by the corresponding equivalent circuit electronic elements.Thus,this makes it possible to analyze the DC circuit coupling that cannot be solved by the past simulation means.The variation of the critical wind(U cr)along with the external connected load and the output voltage and power at different wind speeds and under different external load were analyzed from the perspective of energy harvesting efficiency in AC-DC equivalent circuit.The results show that U cr increases and then decreases with the increase of load in the AC circuit,and U cr decreases with the increase of load in the DC circuit.When the wind speed reaches the maximum value of U cr,the galloping occurs under any resistance.When U≥U cr,the galloping phenomenon occurs,and the output voltage and power increase with the increase of the wind speed.The growth rate has a decreasing trend at high wind speeds.With the increase of the resistance,the output voltage increases,and the power first increases and then decreases.Comparing to AC circuits,the optimum load of the DC circuit is increased from 1.1 to 2.0 MΩ,while the power peak is reduced from 0.08 to 0.04 mW.