A Planar PCB Based Energy Harvester with Voltage Multiplier

A new planar energy harvester based powering supply unit is proposed in this paper with copper plate planar spring, PCB integrated coils and voltage multiplier. The flat architecture has the advantages of low profile and high power density. It is also flexible to adapt to different shapes of the vibration sources and can be applied to the surface to vibration source to capture as much energy as possible. PCB substrate is also more cost-effective than semi-conductor or micro electromechanical substrate. Vibration frequency for copper plate spring is well investigated. It shows a positively linear relationship with spring thickness and reverse proportional to spring length. The magnetic field and flux distribution are deeply explored. The physical size of the coil and magnets are carefully designed to maximize the harvested voltage. The optimal vertical location between magnets and coil is also revealed. A 3.5mm×3.5mm planar energy harvester is designed in this paper. The peak output amplitude is 178.3mV at 150Hz vibration frequency. It achieves twice higher output levels than prior-arts.