Permanent Magnet Synchronous Motor (PMSM) control is a field where real-time processing capabilities play a substantial role in the system’s performance. The usual tradeoff for the processing elements amounts to choosing between a DSP or an FPGA, with the latter seen as more complex to develop and maintain.
This tradeoff usually does not hold out against the specific constraints in the space industry: radiative environments causing SEEs (Single Event Effects), fault tolerance and reliability constraints. One favored answer was to rely on a thoroughly screened space-grade FPGA to bear the brunt of the reliability goals. However, the strong push to reduce recurring costs provides an incentive to explore architecture-based fault-tolerance solutions, where cheaper components verify each other dynamically.
In this talk we present a distributed motor control architecture based on GUARDS (“A Generic Upgradable Architecture for Real-Time Dependable Systems”) allowing:
- A 40kHz motor control loop robust to any single (permanent or intermittent) fault
- Undisturbed operation in a SEE environment
- Distributed FDIR and telemetry
We will then explain why using an industrial-grade FPGA is a particularly good fit for this type of architecture, and how we make it work at Watt & Well: Rapid prototyping on reprogrammable FPGAs allows for quick algorithm de-risking; The inherent parallel architecture of FPGAs allows both flexibility in protocol design and make meeting the real-time deadlines easier; Finally, fine-grained verification capabilities make reaching a very high design assurance level a systematic process.