Vol. 64 | nr. 1 | Ianuarie - Martie 2016 Articolul 4

Noise and Vibrations of Switched Reluctance Machine Drives: Influence of Current Hysteresis Control
(Full text in English)

Switched reluctance machines (SRMs) benefit from major advantages, such as cheap and robust construction and electrical fault tolerance, but also suffer from noise, vibration and harshness (NVH) issues. The present paper focuses on the NVH influence of the current hysteresis controller, which is generally used in SRM drives. The impact of changes in the controller sampling time is experimentally investigated on an 8/6 15 kW (30 kW peak) SRM. In practice the initial hysteresis controller, implemented on a dSPACE platform running at 10 kHz, is compared with an improved version running twenty times faster on external microcontrollers. Tests are performed in the form of runups, in order to study the drive in transient conditions and investigate a continuous speed range, while vibration, current and sound pressure waves are measured. Current waveforms are also simulated using AMESim software to compare with experimental measurements. Both controller implementations are modelled and both runup and constant speed conditions are considered. To identify the frequency content related to the switching process, those simulation results are also analysed before and after having removed the current ripple due to switching through signal processing. Runup results are plotted as waterfall diagrams, which both give a global overview of the frequency content for the considered speed range and allow distinguishing speedorder related harmonics and resonance frequencies. It is observed that the improved controller generates a shift of the spectrum towards higher frequencies with a global reduction of vibration and noise amplitude. Furthermore, the excitation of the dominating first ovalization mode of the SRM is considerably reduced.   
Keywords: noise and vibrations, switched reluctance machines, current hysteresis control, transient condition, waterfall plot