Reduction of EMI from Hybrid Electric Drivetrains

Hybrid electric vehicle technology has proven to be an effective method of reducing fuel consumption and improving the overall efficiency of any given vehicle. The benefits of hybrid technology are extremely valuable to the military, where vehicle rangeand fuel logistics have become of the utmost importance. Perhaps the main drawback to hybrid electric vehicles lies in their high levels of electromagnetic radiation. UQM Technologies, Inc. has years of experience in the development of hybrid and pureelectric vehicles. Our focus in on high efficiency, brushless, permanent magnet drive trains specifically designed for these vehicles. In recent years UQM has begun a program to evaluate the EMI problems in our oun drive systems. We have acquired thetest equipment needed for EMI diagnostics and identified the source(s) of EMI in some of our own drive train products. Phase I endeavors gave us the opportunity to research and develop new technologies that serve to decrease EMI without sacrificingefficiency. Some of those EMI reductions parameters included Space-Vector Modulation (effectively produces waveforms closer to Sinusoidal, without compromising efficiency), Concentric Motor Lead Cable (cancels fields around the outside of the cable),Enclosures with Positive Permeability, EMI gaskets and EMI Filters. All of these parameters have been proved to reduce EMI in our system to varying degrees, resulting in a system that has much reduced radiated emissions from the baseline system. Phase IIwill refine those parameters into a commercially viable, EMI reduced drive system, allowing the parent vehicle to pass all applicable standards relating to electromagnetic radiated emissions.