Power Electronic Interface with an Adaptive MPPT Technique for Train Suspension Energy Harvesters

An electronic interface for the maximization of the power extraction from train suspension energy harvesters is presented in this article. It is made up of a passive rectifier and a dc-dc converter equipped with a digital control unit that implements a novel maximum power point tracking technique. It can settle the voltage at the rectifier output to its optimal value, despite the time-varying train suspension vibrations. By exploiting the measurement of the generator speed, the proposed technique is able to almost instantaneously reach the maximum power point, allowing a power extraction higher than the widely used perturb and observe algorithm. Moreover, the proposed technique is equipped with an adaptive control for ensuring the power maximization despite the tolerances and time-variability of the system parameters. Experimental results validate the theoretical analysis and confirm the superior performance of the proposed interface.