超低电压能量采集器采用热电发生器实现无电池无线传感器

　　超低电压能量采集器采用热电发生器实现无电池无线传感器

　　超低功耗无线传感器节点的测量和控制，结合新的能量收集技术，使得能够产生完全由本地环境能量而不是电池供电的自治系统成为可能。从环境或“自由”能量供电无线传感器节点是有吸引力的，因为它可以补充或消除对电池或电线的需要。当电池更换或维修不方便、昂贵或危险时，这是一个明显的好处。

　　电线的完全缺乏也使得大规模监控和控制系统的扩展变得容易。能量收集无线传感器系统简化了在楼宇自动化、无线/自动计量和预测维护等众多领域的安装和维护，以及许多其他工业、军事、汽车和消费应用。

　　能量收集的好处是显而易见的，但一个有效的能量收集系统需要一个聪明的电源管理方案，将自由能极小的水平成了无线传感器系统的可用。

　　It‘s all about the duty cycle

　　Many wireless sensor systems consume very low average power， making them prime candidates to be powered by energy harvesting techniques. Many sensor nodes are used to monitor physical quantities that change slowly. Measurements can therefore be taken and transmitted infrequently， resulting in a low duty cycle of operation and a correspondingly low average power requirement.

　　For example， if a sensor system requires 3.3 V at 30 mA （100 mW） while awake， but is only active for 10 ms out of every second， then the average power required is only 1mW， assuming the sensor system current is reduced to microamps during the inactive time between transmit bursts. If the same wireless sensor only samples and transmits once a minute instead of once a second， the average power plummets under 20 µW. This difference is significant because most forms of energy harvesting offer very little steady-state power–usually no more than a few milliwatts， and in some cases only microwatts. The less average power required by an application， the more likely it can be powered by harvested energy.