针对无线传感器网络(WSN)节点太阳能收集效率低的问题,提出了一种WSN节点的太阳能高效收集方案,最大功率点跟踪(MPPT)电路由微功耗的可控制光伏电压的闭合环路实现,初始功率跟踪点由通过扫描光伏功率曲线的幅值搜索算法提供,利用简化的梯度上升算法来跟踪随环境变化的最大功率,使其最大化地传输到充电电池.实验结果表明,自适应系统的能量转换效率高达86.7%,在光伏电压低至0.8 V的超低光照强度下仍能有效地收集能量,能有效延长WSN节点的生存周期,可适用于其他应用场合的微小功率太阳能收集.
To solve the problem of the low efficiency of solar energy harvesting in wireless sensor network(WSN)nodes,we propose an adaptive solar energy harvesting system for WSN nodes.The maximum power point tracking(MPPT)circuit is implemented by a closed loop circuit that can control the photovoltaic voltage with micro power consumption.The initial operating point is provided by the amplitude search algorithm of the scanning power curve.The simplified gradient-ascend algorithm tracks the maximum power that varies with the environment and maximizes energy transfer to the battery.Experimental results show that the energy-conversion efficiency of the adaptive system increases to 86.7%.Furthermore,energy can continue to be harvested effectively under the ultra-low light intensity with the photovoltaic voltage down to 0.8 V,effectively prolonging the lifetime of these WSN nodes.Our proposed strategy is suitable for small power solar energy harvested in other applications.
