Abstract: Technology is disclosed herein for a power control and distribution unit (PCDU) of a spacecraft that has a microcontroller to control battery charging from solar arrays. Using a microcontroller within the PCDU reduces the complexity of the PCDU. The microcontroller may be programmable and reprogrammable, which allows the charging of the battery to be adapted to various conditions. For example, the microcontroller can be programmed in accordance with the mission to optimize battery charging for that mission.

Abstract: Technology is disclosed herein for reverse current protection for a photovoltaic module string. An apparatus has a switch connected between each respective PV module string and a power bus. A control circuit closes a set of the switches to connect a set of the PV module strings to the power bus to transfer power from the set of the photovoltaic PV module strings to the power bus. The control circuit determines whether a reverse current flows in the direction from the power bus to any of the PV module strings. The control circuit maintains the switch associated with a particular PV module string in an open state to prevent reverse current from flowing in the particular PV module string responsive to a determination that a reverse current flows in the particular PV module string when the particular PV module string is connected to the power bus.

Abstract: Technology is disclosed herein for reverse current protection for a photovoltaic module string. An apparatus has a switch connected between each respective PV module string and a power bus. A control circuit closes a set of the switches to connect a set of the PV module strings to the power bus to transfer power from the set of the photovoltaic PV module strings to the power bus. The control circuit determines whether a reverse current flows in the direction from the power bus to any of the PV module strings. The control circuit maintains the switch associated with a particular PV module string in an open state to prevent reverse current from flowing in the particular PV module string responsive to a determination that a reverse current flows in the particular PV module string when the particular PV module string is connected to the power bus.

Abstract: The present invention is directed to a circuit for reversing the polarity of a high voltage power supply. Circuits according to embodiments of the invention may include four switches, one or more of which may be solid-state switches. The solid-state switches may include a transistor stack that is supplied a biasing voltage in response to the receipt or removal of a control signal. When the biasing voltage is supplied to one transistor in the stack to change it to the closed or “ON” state, the other transistors in the stack may also be changed to the closed state in a cascading process. The control signal may be a low voltage signal and may be isolated from the solid-state switch by a control switch, which may be an optocoupler.

Abstract: Embodiments of the present invention are directed to a high voltage shunt regulator. The shunt regulator may receive input power of positive or negative polarity and may have two conduction paths. A conduction path may be engaged when the input power is of the proper polarity and the output voltage (or some other characteristic to be regulated) does not match a desired value. The conduction path may include a solid-state shunt in the form of a transistor stack. In embodiments of the invention, the transistor stack includes a number of serially-connected bipolar junction transistors (BJTs), one of which may be operated in the linear region and others of which may be either saturated or in the off state. Voltage regulators may be provided in each stage of the transistor stack to prevent excessive voltage from being applied across the terminals of a corresponding transistor and to provide a shunt path for current when the corresponding transistor is in the off state.