Fault Tolerant Synchronous Multi-Channel Buck Converter for Nuclear Inspection Instruments

Presented here is a compact power supply design for robots operating in nuclear environments, which must be tolerant to damage from ionising radiation. The proposed topology is fault-tolerant through intrinsic redundancy in its layout, with 8 independent channels operating in parallel. This application-specific implementation operates as a buck regulator (step-down) with an input voltage range of 12 V – 48 V DC and a continuous output power of 250 W without requiring passive or active cooling other than ambient air flow. The electrical efficiency of the prototype varies between 70% and 90% at the rated maximum input voltage of 48 V. The architecture of the design is presented, and an analysis of possible failure modes is conducted along with circuit level remediation efforts to make the design intrinsically fail-safe. The fault tolerance and redundancy are illustrated by artificially inducing faults on prototype boards during performance measurements. Finally, the prototype is assembled into a hexapod walker robot and deployed in a radioactive environment as a field test of its radiation and fault tolerant properties.