Real-Time Ton/Toff adjustment and fault prediction in high-voltage IGBT serial switch for pulsed power applications

Abstract

This paper presents a control architecture for dynamic voltage balancing in high-voltage IGBT stacks, addressing transient overvoltage phenomena during switching transitions. The system integrates a three-layer protection scheme - local RC snubbers, TVS diodes, and a global snubber - with adaptive gate timing correction at 20 ns resolution. Realtime edge control is performed locally for each device, based on optical feedback and independent Ton/Toff adjustment. A reduced 14-dimensional control space is achieved by anchoring a reference transistor, ensuring temporal stability and synchronization. The operational behavior of TVS devices under burst-mode stress is characterized as transitional buffering during system tuning. Additionally, methods for predictive degradation analysis-based on UCES(on), Ton/Toff drift, thermal trends, and correction statistics - are outlined, supporting fault diagnostics and preventive maintenance strategies. Preliminary results obtained from the prototype system indicate that it is feasible to develop an algorithm that exhibits desirable trends in adaptive regulation, supporting the overall concept of closedloop switching control in stacked HV structures.

Keywords

• microwave klystron modulator
• hv pulse switch
• adaptive regulation
• pulse slope correction
• series transistor hv ballancing