Magnetically Actuated MEMS Power Conditioning Circuits for Energy Scavenging in SmartGrid Applications

CITRIS research is making possible novel devices that will efficiently collect and store electrical energy scavenged from energized conductors such as common electrical appliance cords and higher voltage power distribution and transmission lines and circuit components. These sensors need only be placed in proximity to the electric circuits that they monitor. MEMS techniques are used to efficiently condition, by electromechanical means, the electrical energy extracted by these devices so that this energy can be used to operate miniature sensors and tiny radios that can be seamlessly integrated into a Smart Grid. These microsensors for monitoring electrical parameters (AC current, voltage, and power) can simply be placed near energized conductors – appliance cords, cables, conductors on overhead power lines – to measure the electrical quantities and broadcast the values via miniature radio chips which are critical for smart building energy infrastructures. Energy scavengers to power such microsensors have traditionally required high-efficiency rectifiers to convert the scavenger output voltage from AC to DC. This research will endeavor to produce an innovative new rectifier design that will employ a tiny magnetically operated MEMS switch which alternates the polarity of the scavenger output voltage twice per cycle of the AC waveform, a switch that will be activated using a permanent magnet driven by the magnetic field produced by the current flowing in the monitored conductor.