Abstract:

Under the background of “dual carbon”,the integrated high precision current measurement of intelligent appliances is required in the power supply and distribution network.The existing equipment can not simultaneously meet the needs of accuracy,range and volume constraint at the same time.To solve the problems of easy saturation and small linear measurement range caused by the small magnetic core in the limited space,a multi-core current sensor is designed based on the self-excited fluxgate.The average excitation current model based on arctangent magnetization fitting curve is constructed.The multi-objective genetic algorithm is adopted to optimize the structure and electromagnetic parameters with the targets of volume and accuracy.On this basis,the closed-loop prototype with three magnetic cores and four windings is trial produced.Compared with LEM cab,the outer diameter of the sensor prototype is reduced by 25% on the premise of ensuring the linearity.The accuracy is better than the national standard level 0.2.The measurement range meets the requirements of circuit breaker measurement.

Key words: self-excited fluxgate, nonlinear model, multi-objective genetic algorithm, system of multi core closed loop