Experimental and theoretical investigation of high-frequency electromagnetic noise generation in an electronic water pump

Abstract

From experimental and theoretical perspectives, this paper investigates the generation mechanism of electromagnetic noise (EN) in an electronic water pump (EWP). A test-rig for EWP vibration and noise measurement is constructed, and powered-normal and motored tests are performed for comparison. Experimental results reveal that high-frequency noises exhibiting a symmetrical umbrella-shaped distribution in the time-frequency domain are electromagnetic noises. These noises are mainly concentrated in the frequency band around the carrier frequency and are related to the EWP control strategy. Based on a detailed analysis of the basic principle and implementation procedure of space-vector pulse-width modulation (SVPWM), a simulation model of an EWP control system with delta-connected stator windings is established. Both theoretical analysis and simulation results indicate that inherent switching harmonics and waveform distortions of SVPWM produce high-order output-voltage harmonics. The subsequent induction of high-order harmonic stator currents, fluctuating radial-electromagnetic-force waves and structural vibrations leading to high-frequency ENs of the EWP are theoretically inferred from electromagnetic principles. For practical applications, the high-frequency EN of EWPs can be mitigated by optimizing SVPWM parameters to suppress waveform distortion. The findings of this paper can be directly applied to the design of vehicle-mounted EWPs and can be extended to the engineering-oriented electromagnetic-noise control of other motor products.