Impedance matching circuit for synchronous switch harvesting on inductor interface

With the use of the technique named synchronous switch harvesting on inductor (SSHI), the piezoelectric energy harvesting efficiency can be greatly improved compared to the standard energy harvesting (SEH) interface. However, the SSHI output power is significantly influenced by its load voltage or load impedance. This paper presents a power conditioning circuit intending to maximize the amount of power extracted from the SSHI interface. The model of a buck-boost converter working in discontinuous current mode is constructed, with the converter's behavior in good agreement with the SSHI optimization criteria. Experimental results validate that the conditioning circuit is able to optimize the SSHI interface output, and hence enhance the responses of the circuit for various load impedance.