Method for maximizing the solar cell OPTO-electronic conversion efficiency in optically controlled hydraulic actuators

摘要

A method for optically powering and controlling a hydraulic actuator in which the electrohydraulic servo valve is powered and controlled by a solar cell, with incident light at optimum level, but frequency-modulated at low amplitude, allowing optimum impedance matching to the servo valve solenoids. The signal is F.M. detected using a discriminator, which outputs are applied to the bases of two transistors in series with the electrohydraulic servo valve solenoids. The nearly constant output impedance of the solar cell or a follow-up amplifier allows optimum performance of the discriminator. The unique feature is the operation of the solar cell at a light level which is optimum for efficiency of the system.