The Boeing Company

Hughes Electronics Corporation

Winnie W Choy

Stanley Canter

Robert Matthew Martinelli

Craig H Becker-Irvin

Ich D Ngo

Apparatuses and methods for optimizing power generation of a solar array are disclosed. The bus voltage is regulated with a regulator controlled through one or more reference signals. When the power bus is being used by electrical systems that are tolerant of a higher variable voltage range, the bus voltage can be temporarily set higher by a commanded reference signal to allow additional solar array power to supply to the power bus. The peak power point may be identified through an established relationship with the solar array performance as a function of temperature, season and/or the age of the solar array. In addition, a reference signal controlled by one or more temperature sensors on the solar array may also modify the bus voltage set-point. Improved solar array power may be extracted from spacecraft beginning-of-life to end-of-life operations due to low insertion loss of a direct energy transfer scheme.

Solar array peak power extraction

A current controller for a spacecraft comprises ripple regulators and a pulse width modulated regulator. Ripple regulators receive current from associated current sources and pass current to or shunts current away from the bus. The pulse width modulated regulator receives current from another current source and passes a portion of the current to the bus. This regulator varies its set point to float between ripple regulators passing current and the ripple regulators shunting current and adjusts a portion of current that is shunted away from the bus. The current shunted by the regulators form a total shunt current. The variable set point of the pulse width modulated regulator varies as the total shunt current varies. The ripple regulator set points do not vary in this manner. An error generation circuit generates an error that adjusts the ripple regulator and the pulse width modulated regulator to a desired bus voltage level.

Sequential shunt solar array controller

In a high power system, plural batteries provide back-up power when primary power is unavailable. Each battery has an associated discharge controller which is controlled by a local bus control amplifier which regulates the power bus voltage set-point lower than the main bus voltage set-point. A single main bus control amplifier tightly regulates the power bus to a main bus voltage set-point and controls charging and discharging of all batteries to prevent charging of one battery at the expense (discharge) of another battery. There is one master battery discharge controller, with the remaining controllers being slave units. A local bus voltage set-point of each slave unit varies under the control of a slave unit current sharing amplifier which compares its own discharge current to the average discharge current, and an error signal modifies the reference voltage in the local bus control amplifier to allow equal discharge current from all batteries.

Battery discharge current sharing in a tightly regulated power system

An autonomous lithium-ion cell balancing system with integrated voltage monitoring includes a lithium-ion battery having a plurality of cells, a cell balancing circuit and a cell balancing control circuit. The heart of the cell balancing circuit is a plurality of gated cell balancing converters that are connected with the battery cells and a common share bus. Each gated lithium-ion cell balancing converter receives and input drive voltage and an input sample voltage and transfers energy from highly charged lithium-ion cells to the less charged lithium-ion cells, forcing all cells to have the same energy level. Further, the gated cell balancing converter provides a telemetry output voltage analog to an input cell voltage, eliminating the need for a separate cell voltage monitor.

Autonomous battery cell balancing system with integrated voltage monitoring

A system ( ) and method ( ) for charge and discharge equalization of a lithium-ion battery having a plurality of cells ( ) in series. A central charge controller ( ) and a central discharge controller ( ) command a rate of charge to individual charge controllers ( ) associated with each cell ( ) of the battery for maintaining equalized charge at each cell ( ) of the battery. The charging and discharging is initiated upon sensing a predetermined maximum charge threshold voltage ( ) and a predetermined minimum discharge threshold voltage ( ) at each cell in the series of cells.

Method and system for charge equalization of lithium-ion batteries

A diode-resistor network for modifying the gain/bandwidth of the feedback loop. The feedback loop gain modifier circuit comprises two (2) diodes and a resistor coupled and parallel with a resistor in the AC feedback path of an amplifier. The diodes are connected such that one diode conducts on a voltage bus overshoot and the other diode conducts on a voltage bus undershoot. In this manner, during large step load transients, one of the gain modifier circuits diodes conducts thereby coupling the resistors in parallel resulting in a modified the gain/bandwidth of the feedback loop. In this way, the feedback gain modifier circuit does not affect the small signal feedback loop stability because it is only activated when a large transient is present.

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Cerritos, CA, United States of America

Winnie W Choy