Taylor T. Johnson — Page 4

arXiv2014

Virtual Prototyping and Distributed Control for Solar Array with Distributed Multilevel Inverter

In this paper, we present the virtual prototyping of a solar array with a grid-tie implemented as a distributed inverter and controlled using distributed algorithms. Due to the distributed control and inherent redundancy in the array composed of many panels and inverter modules, the virtual prototype exhibits fault-tolerance capabilities. The distributed identifier algorithm allows the system to keep track of the number of operating panels to appropriately regulate the DC voltage output of the panels using buck-boost converters, and determine appropriate switching times for H-bridges in the grid-tie. We evaluate the distributed inverter, its control strategy, and fault-tolerance through simulation in Simulink/Stateflow. Our virtual prototyping framework allows for generating arrays and grid-ties consisting of many panels, and we evaluate arrays of five to dozens of panels. Our analysis suggests the achievable total harmonic distortion (THD) of the system may allow for operating the array in spite of failures of the power electronics, control software, and other subcomponents.

cs.DC↗

arXiv2012

Safe and Stabilizing Distributed Multi-Path Cellular Flows

We study the problem of distributed traffic control in the partitioned plane, where the movement of all entities (robots, vehicles, etc.) within each partition (cell) is coupled. Establishing liveness in such systems is challenging, but such analysis will be necessary to apply such distributed traffic control algorithms in applications like coordinating robot swarms and the intelligent highway system. We present a formal model of a distributed traffic control protocol that guarantees minimum separation between entities, even as some cells fail. Once new failures cease occurring, in the case of a single target, the protocol is guaranteed to self-stabilize and the entities with feasible paths to the target cell make progress towards it. For multiple targets, failures may cause deadlocks in the system, so we identify a class of non-deadlocking failures where all entities are able to make progress to their respective targets. The algorithm relies on two general principles: temporary blocking for maintenance of safety and local geographical routing for guaranteeing progress. Our assertional proofs may serve as a template for the analysis of other distributed traffic control protocols. We present simulation results that provide estimates of throughput as a function of entity velocity, safety separation, single-target path complexity, failure-recovery rates, and multi-target path complexity.

cs.RO↗