High Temperature Capacitor Films with Reduced Dissipation Losses for High Voltage AC-DC Inverters

Abstract:
High temperature capacitor films having reduced dissipation losses at 150deg C have been developed for high voltage inverter applications. As operating temperature and frequency increase, dissipation losses in these films are reduced. This advantageous behavior is opposite to how typical high heat polymer films respond to increasing temperature and frequency. For example, Dissipation Factor Df for the new film is about 0.0047 at room temperature at 100kHz. Df drops to 0.0027 when temperature increases to 150deg C at the same frequency of 100kHz. For PEN films (polyethylene naphthalate) the values are 0.0074 and 0.0115, respectively. The higher losses for PEN at high temperatures limit its use to about 125deg C to avoid excessive heat generation in the capacitor. Reduced losses in the dielectric film can lead to overall reduction in heat generation in the capacitors, which in turn leads to overall efficiency gain in the inverter module.