Modelling and control of a boost converter for irregular input sources

In this study, the authors present the analysis and development of a boost-type switching converter for efficient power conversion from a source with an arbitrary low-frequency voltage waveform to a DC storage medium such as a battery. This type of energy transfer is of great interest in energy conversion systems involving low-frequency, time-varying input sources such as vibration energy harvesting and marine wave energy conversion. Motivated by these applications, a modelling and feedback control scheme is developed for a pulse-width-modulated (PWM) boost converter. In particular, conditions under which the converter would act as a `pseudo-resistor` as seen by an arbitrary input voltage source are derived. Based on the pseudo-resistive relationship obtained between the input voltage and current, a feedback controller is developed that regulates the input resistance of the converter to a desired value; hence allowing purely active power conversion of an arbitrary band-limited input voltage source to a DC load. Numerical simulations and experimental results are presented that evaluate performance of the proposed modelling and feedback control scheme. An application involving energy conversion for a mechanical vibration system to act as a regenerative damper is considered.