Snubber circuit design considerations for medium-voltage solid-state switches for high-power inverter-based testing applications: A case study

This paper investigates a common problem in the snubber circuits of medium-voltage solid-state AC switches in industrial environments where PWM voltage-source converters are prevalent. The switches considered here were designed to evaluate fault ride-through capabilities for megawatt scale wind turbine generators and other generators with grid-connected stators. It is shown in the paper that, if left unchecked, high-frequency harmonics inherent in the output of inverter-based voltage sources can produce failures in the snubber circuits of AC switches. A case study is presented to analyze this issue, and different solutions are analyzed and implemented to tackle the problem. The experimental results validate the proposed solutions.