Development of Advanced Inverter Duty Motor Bearings for SiC Applications
Abstract
Development of Advanced Inverter Duty Motor Bearings for SiC ApplicationsVariable frequency drives (VFDs) are employed on U.S. Navy ships for many applications including propulsion, pumps, fans, compressors, etc. Currently, Si-based power semiconductor switching devices are widely used in VFDs using pulse-width modulated (PWM) inverters. The high dv/dt PWM inverter output pulses have adverse effects on the system components and the machines they are driving due to insulation stresses and damaging motor bearing currents resulting from common mode voltages (CMVs) and shaft voltages. As a result, specifically to address bearing currents in Si-based VFDs, several mitigation techniques have been suggested to prevent bearing damage including filters, reducing the common-mode voltage, improved modulation strategies, insulating the bearings, and using a brush to ground the rotor shaft. What has been missing from the past work, which is a Science and Technology (S&T) knowledge gap, is the development of inverter duty motor bearings the focus of this proposal, specifically for advanced SiC applications. Advanced wide band gap (WBG) SiC-based motor drives will have much higher switching frequencies, efficiencies and power densities compared with traditional Si-based power electronics. Prior preliminary research by the PIs demonstrated that the higher dv/dt and di/dt induced by SiC devices causes increased shaft voltages and bearing currents. This research will address the S&T knowledge gaps including answering the questions in order to develop cost effective inverter duty motor bearings for SiC applications, including proving the longevity with accelerated testing. In addition, the SiC inverter offers an untapped resource as a diagnostics tool, which will be researched in order to identify bearing wear through the current and voltage signatures of the drive.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 29, 2020
- Source ID
- N000142012193
Entities
People
- Annette Vonjouanne
Organizations
- Baylor University
- Office of Naval Research
- United States Navy