Solar Array Peak Power Extraction via Dynamic Bus Voltage
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Solution Overview
Problem
Conventional solar array power regulation systems in space applications suffer from inefficiencies, leading to suboptimal power generation due to fixed bus voltage mismatch with the solar array's peak power point, resulting in power losses and reduced efficiency, especially at varying temperatures and ages, and require additional components like second-stage DC-DC converters, increasing mass and losses.
Innovation Solution
A system that dynamically regulates the bus voltage using a control circuit with reference signals, including temperature and age-based inputs, to optimize solar array power extraction by temporarily setting the bus voltage higher for voltage-tolerant systems, such as electric propulsion, while maintaining a stable voltage for sensitive systems, thereby achieving direct energy transfer with low insertion loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the solar array voltage is fixed at the electrical system bus voltage level, then the electrical systems are protected from voltage variations, but the solar array cannot operate at its peak power point and power generation efficiency is reduced
Solution Approach 1:
The patent implements a dynamic bus voltage regulation system that adjusts the solar array operating voltage based on real-time conditions. The control circuit continuously monitors solar array current and voltage, and dynamically adjusts the PWM duty cycle to track the peak power point while adapting bus voltage to system requirements, resolving the contradiction between fixed voltage protection and variable peak power extraction
Solution Approach 2:
The system changes the operating parameters (voltage and duty cycle) of the solar array based on environmental conditions such as temperature, season, and array age. By adjusting these parameters dynamically, the system maintains electrical system protection while optimizing power extraction at varying operating conditions
2Productivity
If a conventional peak power tracker with battery-on-bus topology is used, then solar array power extraction is improved, but additional components increase system mass and complexity
Solution Approach 1:
The patent merges the peak power tracking function with the existing bus voltage regulator into a single integrated control system. The PWM regulator performs both voltage regulation and peak power tracking simultaneously, eliminating the need for separate peak power tracker components and reducing system mass and complexity while maintaining improved power extraction
3Reliability
If a second stage DC-DC converter is added to regulate unregulated peak power tracker output, then bus voltage regulation is achieved, but spacecraft mass increases and power conversion efficiency decreases
Solution Approach 1:
The patent extracts the voltage regulation function from a separate second-stage DC-DC converter and integrates it into the primary PWM regulator stage. By taking out the redundant regulation stage and combining functions, the system achieves bus voltage regulation with a single converter, reducing spacecraft mass and minimizing power conversion losses
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances solar array power generation efficiency by minimizing insertion losses and providing additional power during orbit raising, particularly at the beginning of life, while maintaining stability for sensitive systems, thus improving overall spacecraft power management.
Implementation Method 1
a solar array for converting solar radiation to electrical power
Data Source
AI summary
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.