| 摘要 |
As applications of variable frequency drives (VFD) (50) continue to grow so do challenges to provide VFD(50) systems meeting application specific requirements. For multiple reasons to include safety standards and electromagnetic interference, reduced ground leakage current is desireable. Building high ouput voltage VFDs (50) using transitors rated at voltages lower than the VFD ouput votlage is desireable for economic resons. The apparatus and method described herein meet these challenges and others, in part by placing an electrically insulating plaste (cpl76) having high thermal conductivity, a low dielectric constant, and high dielectric strenght between the heat sink plate of a VFD power semiconductor module and a grounded cooling plate (80 TE). The positive effects of this plate installation include reducing ground leakage current induced by system capacitances to ground upon high frequency voltage steps and increasing the effective dielectric strength of the VFD's(50) transistor modules engaging in high reliable VFD (50)votlage ouput for a given transistor rating.
|
