Integrated Motor Controller for Reaction Wheel Scalability
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Solution Overview
Problem
Existing momentum control devices for small satellites face challenges in scalability, efficiency, reliability, and space constraints, as they require smaller reaction wheels and motors while maintaining performance and reducing noise.
Innovation Solution
A controlled motor assembly combining a high-speed AC permanent magnet synchronous motor with optimized motor control electronics that maximizes digital signal processing, minimizes analog signal processing, and employs nonvolatile memory to detect and configure parameters for different motor types, along with a digital control system using field-oriented control and power switch elements like Gallium Nitride transistors, to achieve efficient and scalable motor control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional motor control electronics are used in small satellites, then the system can maintain basic functionality, but the device size, weight, and cost increase while reducing scalability
Solution Approach 1:
The patent combines the motor controller and motor into a single integrated assembly, where the controller is physically coupled to the motor shaft. This merging eliminates the need for separate mounting structures and reduces overall system size and weight, directly addressing the scalability challenge in small satellite applications.
Solution Approach 2:
The integrated motor controller assembly is designed to be applicable across multiple satellite platforms and momentum control device configurations. The universal design allows the same assembly to be used in different satellite sizes and applications, improving adaptability while maintaining a compact form factor that reduces weight.
2Adaptability or versatility
If traditional motor control electronics are used in small satellites, then the system can maintain basic functionality, but the available space for electronics is exceeded
Solution Approach 1:
The controller is nested within or tightly coupled to the motor structure, utilizing the motor's existing physical envelope. This nesting approach allows the control electronics to occupy space that would otherwise be unused, minimizing the additional area required while maintaining full functionality.
Solution Approach 2:
By merging the controller and motor into a single assembly, the patent eliminates the need for separate housing and mounting space. The combined assembly optimizes space utilization by integrating components that would traditionally require separate volumes, directly reducing the total area occupied.
3Volume of moving object
If smaller motors are used to reduce size, then the device fits small satellite constraints, but noise increases and performance may degrade
Solution Approach 1:
The controller incorporates feedback mechanisms that monitor motor operation and adjust control parameters in real-time. This feedback allows the system to optimize motor performance, reduce vibrations and noise, and maintain efficiency even in the compact motor design, addressing the noise issue while preserving small volume.
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
The solution enables reduced cost, high efficiency, and improved scalability for small satellite applications, reducing weight, parts count, and size while maintaining performance, and can be integrated with various systems like linear position systems and gimbal mechanisms.
Implementation Method 1
a motor, generally driven by a block of motor control electronics, causes the rotor assembly to rotate or spin about a spin axis. As the motor spins the rotor assembly, angular momentum is stored in the rotating inertial element.
Implementation Method 2
As the motor spins the rotor assembly, angular momentum is stored in the rotating inertial element. Angular momentum is then converted to torque (torque being the time derivative of angular momentum). Torque is exchanged with the spacecraft to change its attitude in space.
Data Source
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AI summary
Methods and apparatus are provided for a controlled motor assembly for use in a reaction wheel assembly (RWA). The controlled motor assembly is optimized to work with an AC motor, and includes a filter configured to inhibit electrical and electromagnetic noise from being coupled between a spacecraft power bus and a power bus internal to the RWA, as well as an arrangement of power switch elements providing a path for motor phase currents associated with the AC motor. A digital control system is implemented to receive a command input, position sensor feedback and to retrieve parameters associated with the AC motor from a memory device. Based on the command input, the position sensor feedback and the parameters associated with the AC motor, the digital control system controls activation for the arrangement of power switch elements, and generates data output.