Development of Multi-Inputs Power Management Circuit for Hybrid Energy Harvester

Hybrid energy harvester which integrates both the piezoelectric and electrostatic modules is developed mainly to improve the output power for powering up the Internet of Things (IoT) devices. This paper presents the development of a Power Management Circuit (PMC) for use on the hybrid energy harvester. The circuit is able support two inputs from the hybrid energy harvester, i.e. piezoelectric-electrostatic combination. The circuit comprises of a full-wave bridge rectifier with a buck-boost converter running in Discontinuous Conduction Mode (DCM) to sustain a constant input impedances through a fixed duty cycle for each of the piezoelectric and electrostatic transducers, and the use of pulse voltage which acts as a switch for both sources with a supercapacitor to store the output potentials produced by the energy harvester. Simulation results of the power management circuit show that the output voltage generated is 1.011 V at 50 Hz frequency for each of the input source. Experimental results however show that the output voltage obtained from the power management circuit is 400 mV DC across a supercapacitor. Hence, it indicates that the voltage has been successfully rectified.