REVIEW OF ENERGY MANAGEMENT CIRCUITS FOR PIEZOELECTRIC VIBRATION ENERGY HARVESTERS

With the rapid developments of internet of things (IoT) technology, the traditional battery-based power supplies cannot meet its requirements of power supply. Using a piezoelectric energy harvesting technology which converts the mechanical energy into electrical energy, can provide a stable and long-lasting power supply for IoTs, and has wide application prospects. Based on the discussion of the electrical characteristics of piezoelectric vibration energy harvester, this paper comprehensively summarizes state-of-the-art energy management circuits for piezoelectric vibration energy harvesters. The energy management circuits are usually composed of an AC-DC converter and a DC-DC switching converter (including the control algorithm of converters). The former is used to convert the AC voltage from the piezoelectric vibration energy harvester into DC voltage, and the latter is used to improve the efficiency of energy harvesting. Firstly, for AC-DC converters, the working principles and characteristics of full bridge rectifiers, voltage doublers, synchronized switch harvesting on inductors (SSHI) and synchronized switch harvesting on capacitors (SSHC) are analyzed. Then, the typical switching converters for piezoelectric energy harvesting are discussed, including inductor-based/ capacitor-based/ and transformer-based DC-DC switching converters and inductor-based AC-DC switching converters, besides, their characteristics and applications are analyzed. Finally, according to the characteristics of piezoelectric energy harvester, several typical control algorithms for maximum energy harvesting are analyzed, including maximum power point tracking, impedance matching and synchronous electric charge extraction (SECE). Through the comprehensive analysis and summary of the energy management circuits for the piezoelectric vibration energy harvesters, this paper reveals its bottleneck problems and future development trends, it has important reference values for the research and development of the self-powered piezoelectric energy harvesting systems.