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

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.