Development of Resonant Excitation System for Electromagnetic Flowmeter Based on SPWM
In order to make the EMF operate reliably for a long time,it is necessary to reduce the power consumption of the excitation system and heat generation.Therefore,this paper proposed a resonant EMF excitation control scheme based on SPWM control,changing the previous constant-current source drive mode,using high-frequency switching voltage source drive,while the excitation circuit in series with a capacitor to reduce the impedance of the circuit,and developed a prototype and carried out ex-perimental validation.Power consumption test results show that,under the condition of the same excitation current,the power con-sumption of the developed excitation system is 58.3％of the original system,and the power consumption of the excitation power supply is 69.2％of the original system.The water flow calibration results show that when the excitation frequency is 109.5 Hz,the calibration accuracy of the developed system is better than 0.5 level in water flow calibration from 0.5 m/s to 5 m/s.It can be seen that the developed excitation system has low power consumption and high measurement accuracy.
EMFhigh frequency sine wave excitationSPWMseries resonanceexcitation system consumptioncalibration accuracy
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