Power analysis and maximum output-power scheme for inductively coupled resonant power receivers

Although microsensors nowadays can save money, energy, and lives, highly functional devices can exhaust a tiny battery very quickly. Harvesting ambient energy can help replenish the battery, but only when an ambient source is available. Unfortunately, many embedded microsensors are small, stationary, and enclosed, so thermal gradients, motion, and light are absent. Wireless power in these cases is often the only option left. But since the receiving coil is small and centimeters away from the transmitter, drawn power is low. Switched resonant bridges are popular in this respect because they output more power with fewer components than their non-switched and non-resonant counterparts. But still, power can be so low that losses can be overwhelming. This paper introduces a power analysis and proposes a skipping collection scheme that boosts output power. Analysis and simulations show how switched resonant bridges consume conduction and switching power and how dispersing collection times can boost output power.