High power modulator new design architectures enabled by new 200 °C-class high temperature insulation - a preliminary investigation

An advanced insulating material developed for thermal management, with a 150 °C glass transition temperature (T_g) in a laminate insulated metal substrate (IMS^TM) construction, is characterized for its especially low partial discharge behavior. Rounding all sharp edges, and testing while immersed in dielectric fluid eliminates discharges in air above the test assembly. The insulation's partial discharge inception voltage (PDIV) at room temperature, in a dielectric fluid environment, is above 4,000 V, at 60 Hz ac. This material has shown to withstand aging in air at temperatures and dc voltages as high as 175 °C and 960 V, up to 2000 hours. This new material is available in square feet area sizes and represents the first new high voltage (i.e., for voltages>24 V_ac/dc) large area laminate insulation for thermal management of next generation medium voltage high power modulators. Partial Discharge (PD) testing, such as its inception and extinction voltages (PDIV and PDEV), may be used to assess the presence of microelectric discharges in insulating systems at design operating voltages. Through accelerated aging, PD activity can be utilized as a quality control to predict material life in design and qualification of a material for power applications.