DSHBR data - Access-2021-13852

This paper describes the design and practical application of a dual-stage H-Bridge (DSHBR) circuit to reduce the rectification losses and to minimise ripples in piezoelectric energy harvesting. The proposed DSHBR circuit integrates both AC-DC and DC-DC conversion processes using bidirectional switches and a step-up DC-DC converter, which applies to both positive and negative half cycles. One additional feature is that it does not require external power to turn on the bidirectional switches (Vth < 0.3 V). Such feature facilitates active rectification at very low AC voltages (Vac < 0.5) generated by the piezoelectric device (PD). To validate the performance of the proposed circuit, a series of experimental tests were conducted. Firstly, the performance of circuit was investigated using a shaker to generate high and low frequency excitations. Next, real-life testing was conducted with human arm motion as the source of excitation. Then, the ability of the entire system to charge solar batteries was investigated. The outcome shows that the DSHBR circuit prominently increased the rectified voltage and the output power while stabilising the DC voltage when compared to the conventional H-Bridge circuit.