Bringing Fault Tolerance to Hardware Managers in PESNet

The goal of this research is to improve the communications protocol for Dual Ring Power Electronics Systems called PESNet. The thesis will focus on making the protocol operate in a more reliable manner by tolerating Hardware Manager failures and allowing failover among duplicate Hardware Managers within PEBB-based systems. In order to make this possible, two new features must be added to PESNet: utilization of the secondary ring for fault-tolerant communication, and dynamic reconfiguration of the network. Many ideas for supporting fault tolerance have been discussed in previous work and the hardware for PEBB-based systems was designed so support fault tolerance. However, in spite of the capabilities of the hardware, fault tolerance is not supported yet by existing firmware or software. Improving the PESNet protocol to tolerate Hardware Manager failures will increase the reliability of power electronics systems. Moreover, the additional features that are needed to perform failover also allow recovery from link failures and make hot-swap or plug-and-play of PEBBs possible. Since power electronics systems are real-time systems, it is critical that packets be delivered as soon as possible to their destination. The network latency will limit the granularity of time that the control application can operate on. As a result, methods to implement the required features to meet real-time system requirements are discussed and changes to the protocol are proposed. Changing PESNet will provide reliability gains, depending on the reliability of the components that are used to construct the system.