Abstract
This study presents a novel signal description based on stochastic signal analysis, applicable to electromagnetic, piezomagnetic or other transducers without energy storage as a capacitor. At present the peak power and average power are used to characterize the energy transducer. As for non-harmonic signals the last-mentioned quantities compress the time in a way, that inhibits predicting the transferable energy for different charge based interface circuits to charge a storage capacitor.
The main objectives are first, to represent the data meaningfully, second, to incorporate the effect of lossy rectifiers on the raw data and third, to evaluate the performance of chosen energy harvesters together with the interface circuits efficiently. The foundation relies in considering the measured time signal as a realization of an ergodic process. The probability density function (PDF) and the cumulated density function (CDF) build the fundament and are used to link the signal magnitudes to their probability of occurrence. New distribution functions are introduced to determine both, the charges and the energy of an electromagnetic transducer above a specific signal amplitude, which can be imposed by a voltage drop of one or several components. The presented method is further applied on the well-known full wave rectifier and to calculate its momentary efficiency, being limited by 92% for a sinusoidal signal.
As a result, the paper applies the new stochastic signal representation to energy harvesters to extends the state-of-the-art time and frequency signal analysis. Different interface circuits with energy storage can be quickly calculated for different initial storage voltages, much faster than powerful network simulators.
