Microprocessor control of multiple peak power tracking DC/DC converters for use with solar cell arrays

US5327071A · kind A · utility

Assignee

• The United States of America as represented by the Administrator of the National Aeronautics and Space Administration · US

Inventors

• Martin Frederick · Cedar Park, US
• Joel B. Jermakian · Laurel, US

Key dates

• Filing date: Jul 12, 1993
• Grant date: Jul 5, 1994
• Expiry date: Jul 12, 2013

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S323/906
• WIPO field: Control
• WIPO sector: Instruments

Abstract

A method and an apparatus for efficiently controlling the power output of a solar cell array string or a plurality of solar cell array strings to achieve a maximum amount of output power from the strings under varying conditions of use. Maximum power output from a solar array string is achieved through control of a pulse width modulated DC/DC buck converter which transfers power from a solar array to a load or battery bus. The input voltage from the solar array to the converter is controlled by a pulse width modulation duty cycle, which in turn is controlled by a differential signal comparing the array voltage with a control voltage from a controller. By periodically adjusting the control voltage up or down by a small amount and comparing the power on the load or bus with that generated at different voltage values a maximum power output voltage may be obtained. The system is totally modular and additional solar array strings may be added to the system simply be adding converter boards to the system and changing some constants in the controller's control routines.