A high speed induction machine with two speed transmission as drive for electric vehicles

The electric machine combined with the transmission is a fundamental part of an electric vehicle. The paper presents a new high speed induction machine coupled with a two-speed automatic shifting transmission in order to reduce size, weight and costs and to improve the efficiency. Its rotation speed is up to 23000 rpm offering a high power density. Machine parameter and simulation results are given to show the potential benefits of a two speed gearbox. The new design is compared with traditional drive trains with fixed reduction ratio. A liquid cooling system using a small gap for the flow was designed in order to increase the continuous output power. The drive unit was built and examined on the test bench. It has been shown that high speed drives offer the possibility of further improvements of the electric traction system of road electric vehicles.