Performance of Active Magnetic Energy Harvesters Feeding Constant-Voltage-Type Loads Under High Primary Currents

The letter discusses the performance of clamped-type active magnetic energy harvester (MEH), supplying power to a constant-voltage-type load via transfer-window-alignment controlled rectifier. The presented analysis investigates practical harvesting potential of active MEH operating under high primary currents and compares it to that of a passive (uncontrolled rectifier equipped) MEH. It is revealed that harvested active MEH power may be increased for a given core by reducing the number of secondary conductor turns <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i>, yet it is accompanied with escalated current ratings of secondary conductor and rectifier components. Theoretical harvesting potential of active MEH is shown to be ∼38% higher than that of an optimally designed passive MEH utilizing the same magnetic core under similar operating conditions (i.e., primary current magnitude and load voltage). However, somewhat lower figure of merit should be expected in practice since <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">N</i> cannot be reduced to zero. Experimental results of active MEH harvesting ∼285 W (which is ∼95% of the theoretical upper harvested power bound) from a conductor carrying 300A<sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">rms</sub> at 50 Hz validate the revealed findings.