Analog Coolant Pump Speed Control for Radiation-Reliable Spacecraft Cooling
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Solution Overview
Problem
Conventional digital control systems for coolant pumps in spacecraft cooling systems are prone to deterioration due to radiation and environmental conditions in space, leading to sub-optimal operations and reduced coolant flowrate, especially during extended missions.
Innovation Solution
An analog motor speed control circuit using a temperature sensor to generate a motor control signal based on coolant temperature, eliminating the need for microcontrollers and FPGAs, and incorporating discrete hardware limits to ensure motor operation within a designed window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If digital control systems (microcontrollers, FPGAs) are used to control coolant pump motors, then control flexibility and programmability are improved, but reliability deteriorates due to radiation and environmental conditions in space
Solution Approach 1:
The patent replaces digital electronic control systems (microcontrollers, FPGAs) with an analog control circuit that uses continuous electrical signals to control motor speed. This substitution eliminates the vulnerability of digital systems to radiation-induced bit flips and logical errors, while maintaining the ability to adjust motor speed through analog voltage control. The analog circuit processes temperature sensor signals and generates motor control signals without using any digital processing elements.
Solution Approach 2:
The patent changes the control parameter from digital discrete values to analog continuous voltage levels. The analog control circuit accepts a temperature-dependent voltage signal and continuously adjusts the motor speed control signal proportionally, enabling smooth speed variation without the quantization effects of digital control. This parameter change improves reliability by eliminating digital logic while preserving control adaptability through continuous signal adjustment.
2Reliability
If analog control circuits are used instead of digital controllers, then reliability is improved by eliminating microcontrollers and FPGAs, but device complexity increases due to discrete hardware components
Solution Approach 1:
The patent combines multiple discrete analog components (operational amplifiers, resistors, capacitors, voltage references) into an integrated analog control circuit that performs temperature sensing, signal conditioning, and motor speed control in a unified hardware architecture. This merging reduces the overall system complexity compared to digital solutions while maintaining reliability through the use of radiation-hardened analog components and eliminating the need for complex digital logic circuits.
3Ease of operation
If conventional digital control systems are used, then ease of operation is improved through programmability, but loss of information occurs due to radiation-induced deterioration
Solution Approach 1:
The patent replaces digital information processing with analog signal processing, where temperature information is directly converted to a proportional voltage signal that continuously controls motor speed. This substitution eliminates the storage and processing of digital data that is vulnerable to radiation-induced bit flips and information loss. The analog system maintains operational ease through continuous feedback control without requiring programmable logic or memory elements.
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 solution provides a reliable and flexible coolant pump speed control, enhancing spacecraft operational life and reducing power consumption, while maintaining coolant flowrate stability across temperature extremes.
Implementation Method 1
A temperature sensor is disposed proximate the coolant loop and is configured to output an electrical signal, wherein a parameter of the electrical signal is dependent on a temperature of the coolant loop at the temperature sensor
Implementation Method 2
An analog motor speed control circuit includes an input connected to the temperature sensor and an output connected to a motor speed regulator of a motor within the motor driven pump
Implementation Method 3
Rotation of the pump is driven by a motor
Data Source
AI summary
A space-based vehicle includes at least one electrical system. The space-based vehicle also includes a cooling system having a coolant loop, a motor driven pump for driving a coolant through the coolant loop, and a radiator through which the coolant loop passes. A temperature sensor is disposed proximate the coolant loop and outputs an electrical signal, wherein a parameter of the electrical signal is dependent on a temperature of the coolant loop at the temperature sensor. An analog motor speed control circuit includes an input connected to the temperature sensor and an output connected to a motor speed regulator of a motor within the motor driven pump, and wherein the analog motor speed control circuit provides a motor control signal from the output and wherein characteristics of the motor speed control circuit depend on a magnitude of a signal received at the input connected to the temperature sensor.