DYNAMICAL AND STEADY-STATE CHARACTERISTICS OF DC MOTORS POWERED BY PHOTOVOLTAIC SYSTEMS VIA DC-DC BUCK-BOOST SWITCH MODE CONVERTER

摘要

This paper presents the dynamical and steady-state characteristics of DC shunt, series and permanent-magnet motors fed by photovoltaic (PV) cells via DC-DC buck-boost (step up-step down) switch mode converter. The photovoltaic cells are designed such that to provide their maximum output power at the rated conditions of the motors. The nonlinearities of the output characteristics of the photovoltaic cells and that of the magnetization curve of the machines are taken into consideration. The output voltage of the DC-DC converter is controlled by its duty cycle with an aim of keeping a fixed voltage across the terminals of the motors at any realistic loading conditions to overcome the problems of the voltage regulation of the photovoltaic cells and the variation of the solar illuminations. It is found that the DC-DC buck-boost switch mode converter is able to achieve fixed voltage across the terminals of the motors and therefore good speed regulation at wide range of loading conditions and solar intensities have been achieved. All of the study is carried out using the Matrix Laboratory Program MATLAB™ environment by building the code required.