A Switched Reluctance Motor Drive using Photovoltaic Transistors: Principle, Prototype, Experimental and Numerical Results

We designed a new solar-powered electromechanical drive: the photovoltaic transistor inverter-fed switched reluctance motor. A photovoltaic transistor is a conventional photovoltaic cell used as a light-controlled transistor. To obtain a motor drive, a set of photovoltaic transistors switch the current in the motor phases from an external DC power source. The switching is achieved by controlling the sunlight hitting the photovoltaic transistors using a shutter driven by the motor rotor. If the external source is a solar panel, the resulting system is able to convert light energy into mechanical energy, without the need of any brushes or other power electronics components. It could be more affordable and reliable than conventional systems, and therefore well suited for off-grid applications like water pumping. In this article, we first discuss the operation of a photovoltaic transistor. A model for the photovoltaic transistor is proposed and validated. Then, we clarify the operating principle of a photovoltaic transistor inverter. Finally, we report experimental and numerical results on the first photovoltaic transistor inverter-fed switched reluctance motor. Our prototype uses a SRM 6/4 and 12 PVTs. It is here connected to an external 12 V DC power source as a step before studying the supply by a solar panel. Results show that the PVT inverter-fed switched reluctance motor is operating as expected and provides useful power.