Abstract: A solar cell voltage regulating arrangement which is particularly advantageous for use in spacecraft includes a light valve such as a liquid crystal cell disposed before the solar cell, to thereby controllably vary the light transmission to the solar cell. A control arrangement varies the transmission of the liquid crystal to control the output voltage.

Abstract: A high efficiency, regulated DC supply combines the rectifying and a series regulating elements into one device such as a MOS FET which is gated "on" or "off" by the polarity of an AC voltage from a transformer winding. During the "on" state of the MOS FET a feedback network varies the MOS FET gate voltage as necessary to provide regulation of the DC output voltage during the "on" period.

Abstract: A voltage regulator for controlling the voltage of a bus powered by N solar cell arrays. Digital shunts are coupled to N-1 of the arrays. A linear shunt is coupled to the remaining array. Current passing through the remaining array is sensed by the linear shunt which, in response thereto, turns on and off various ones of the digital shunts to maintain the desired voltage on the bus.

Abstract: A highly efficient series regulator for use where output voltage may closely approach input voltage uses the channel of a field effect transistor as a series voltage-dropping element. The conduction of the channel of the field effect transistor is controlled without consumption of appreciable power in the control circuitry for the transistor. Presently available power field effect transistors are of p-channel enhancement mode type. Their threshold voltages are sufficiently high as to make difficult the closing a d.c. feedback loop as will allow output voltage to approach closely input voltage. This problem of closing the d.c. feedback loop is overcome by using voltage boost circuitry, powered from the input voltage supply to the regulator, against which to refer the error signal applied to the gate electrode of the field effect transistor.

Abstract: In a satellite power distribution system such as for use in a communications satellite, a first load powering power distribution bus receives power from a first solar panel. A second load powering power distribution bus receives power from a second solar panel. One of the buses is connected to a battery system to provide power to loads during night periods. The loads connected to the other bus are not powered during the night periods.

Abstract: A highly efficient battery charging system in which the ampere-hour discharge of the battery is sensed for controlling the battery charging rate. The battery is charged at a relatively high charge rate during a first time period proportional to the extent of battery discharge and at a second lower rate thereafter.

Abstract: A satellite power system in which solar cells provide power to a load during sunlight hours and also charge, through regulators, rechargeable batteries which provide power during dark periods. In order to prevent the batteries from being overcharged by solar cell current bypassing the regulators (through the load connection) each battery is protected by a redundant protection system including a pair of diodes and switch means normally connecting one of the diodes between the battery and the load. If the one diode fails or shorts, the switch means connects the other diode between the battery and the load; the voltage across the one diode and current therethrough are sensed to determine if the diode has failed.