A MPPT Technique With Both Simultaneous and Individual Voltage Regulation for Multiinput Piezoelectric Energy Harvesting

The traditional maximum power point tracking (MPPT) technique uses the time-multiplexing strategy to adjust the rectified voltages of piezoelectric transducers (PZTs) to their optimal values. This results in the inability to perform voltage regulation of multiple PZTs simultaneously. Hence, this article presents a multiinput MPPT technique with both simultaneous and individual voltage regulation. The proposed regulation method is performed by an adaptive series switches network that can be accessed or withdrawn arbitrarily to adjust the rectified voltage in time. In addition, the alternating current–direct current (ac–dc) conversion for multiple PZTs is implemented by a multiinput rectifier-less interface with a single inductor configuration, which can harvest energy from multiple PZTs. The experiment confirms that the rectified voltages of multiple PZTs can be performed in both simultaneous and individual modes, and a peak MPPT efficiency of 97% is obtained. The output power of every PZT is 413 <bold xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><i>μ</i></b>W when <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">V</i><sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">oc</sub> = 5.6 V, which boosts 4.2 times that of a traditional full-bridge rectifier.