Improved matching of photovoltaic solar arrays supplying DC motors through controlled motor saturation

This paper presents a method for increasing the daily output mechanical energy supplied by DC motors directly connected to solar cell arrays (SCA). Without any interfacing circuitry between the PV-array and the DC series motor, an increase of about 10% in the mechanical energy can be achieved. The procedure is based on the use of series DC motors with nonlinear magnetic circuits, so that these motors are driven into their saturation region during normal operation. It is shown that through proper selection of the parameters of the motor's magnetization characteristics (initial mutual inductance and the flux saturation level), improved matching between the PV-array and the DC motor is possible.