Motor Insulation Material Development for Improved Power Density

The application of reliable, long life electrical machinery in the All Electric Navy is critical for the success of future naval warfare. Development of a Pulse Width Modulated (PWM) inverter fed Permanent Magnet (PM) motor for the DD(X) shipboard propulsion illustrates future trends for large 20 MW, 2000 V, PWM Machines of 310 Tons. Challenges remain with regard to the insulation systems for these large machines. PWM inverters place much greater stress on the insulation system as compared to sinusoidal supplies, due to the high switching frequencies, high voltages and resulting high time rate of change in voltage (dv/dt). These large machines are often operated at voltages that are beyond the partial discharge and corona inception voltage in order to obtain high power density. To obtain long life, new insulation systems developed specifically to address PWM inverter demands are needed to obtain 25-year life goal. Destructive life testing is required to qualify these insulation systems. Test methods and equipment appropriate for the task are needed as well as the preparation and test of samples to establish life curves. SatCon will develop and apply appropriate equipment and methods to support successful application of new insulation systems in these demanding applications.