Abstract
This contribution deals with the topic of the consistent further development of a wheel hub motor for battery electric vehicles (BEV) based on the principle of an outer rotor switched reluctance machine (SRM). The research work presented in this paper was founded by the ERDF.NRW program, Investment for Growth and Employment and the European Regional Development Fund. The R&D project was named Switched-Reluctance fo(u)r wheel (SR4Wheel). Based on the experience made by first prototype Evolution 0 (EVO 0), developed in the Laboratory for Automation Engineering, Power Electronics and Electrical Drives of the Cologne University of Applied Sciences (CUAS), the test results of EVO 1, as well as the redesign, EVO 2 is presented in this paper. The prototype EVO 0, a first proof of concept leads to several optimizations and lessons learned for the predecessor model EVO 1. The overall target of developing such a gearless outer rotor wheel hub motor is the full integration of the complete machine including its power electronics into the given space between the original friction brake and the rim. Furthermore, due to the additional integration of the power electronics, great opportunities in terms of new vehicle design as well as retrofitting capabilities of already existing vehicle platforms can be achieved. Thereby, further drive train assembly space like the engine compartment is no longer necessary. The SRM does not require magnets for torque production which leads to independence from the changeable commodity prices on the rare earth element markets. This paper presents the developing process, testing, and verification of the innovative drive train concept starting with the final CAD of EVO 1. During the testing and verification process a machine characteristic mapping is performed on a drive train test bench and subsequently the results of a finite element analysis (FEA) are plausibility checked by the test bench results. The process continues with energy conversion test scenarios of the project demonstrator vehicle on a roller test bench focused on noise vibration harshness (NVH) behavior and efficiency. As a conclusion, the gained knowledge by evaluating two EVO 1 prototypes on the rear axle of the test vehicle, and the design for the front axle drive train EVO 2 will be presented. As a major task on the front axle, the limited space due to the large disc brake can be identified and solved.
Highlights
As the latest political and industrial discussions and decisions show, the reduction of CO2 emissions are no longer a topic dedicated to the future but are here
The overall target of developing such a gearless outer rotor wheel hub motor is the full integration of the complete machine including its power electronics into the given space between the original friction brake and the rim
During the testing and verification process a machine characteristic mapping is performed on a drive train test bench and subsequently the results of a finite element analysis (FEA) are plausibility checked by the test bench results
Summary
As the latest political and industrial discussions and decisions show, the reduction of CO2 emissions are no longer a topic dedicated to the future but are here now. When comparing Syn-Reluctance motors to SRM’s, the biggest advantage of SRM’s is the complete lack of magnet material, and a real simple and robust rotor, which can be produced and assembled very inexpensively, with no need for gluing parts or inserting magnets into the sheet material This is the main reason why an SRM had been chosen as a wheel hub machine, as simple and price stable as possible for mass production in the future. 25% of its maximum designed torque on the test bench through high radial deformation, the extreme stiff carbon fibre rotor of EVO 1 is able to show the full machine performance while maintaining the air gap of 1 mm.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have