Study on the Magnetic Field Characteristics of Three-phase Cables and Efficient Energy Extraction Methods

Three-phase alternating current is widely used. The magnetic induction line produced by the three phase cable is complicated after the vector superposition, and the energy efficiency of the traditional method is low. Therefore, the aim of this paper is to study the magnetic induction intensity characteristics of three-phase cable and the optimal energy taking position of three-phase cable. The author adopted the methods of ideal two-dimensional modeling, finite element analysis and COMSOL simulation. Based on Mn-Zn ferrite material, a C-type high-efficiency magnetic core matching the characteristics of the cable was designed. This study further reduced the internal resistance of the equivalent power supply by compressing the magnetic circuit. It compensated the reactive power loss by matching capacitor series resonance. It is concluded that a stable DC voltage of 7.6V is obtained by AC/DC converter, and that the ripple coefficient is less than 1%. In addition, the energy extraction performance is significantly better than that of the traditional O-type energy extraction core.

I. Introduction

Three-phase alternating current, commonly referred to as three-phase power, is a form of electrical energy transmission. A three-phase AC power source is composed of three AC potentials with equal amplitudes, equal frequencies, and phase differences of 120° sequentially. Compared to single-phase AC power, three-phase AC power exhibits significant advantages in power generation and energy transmission: (1) In terms of power generation, three-phase generators can output higher power than single-phase generators of the same size. (2) In power transmission, for the same transmitted power, three-phase systems save approximately 25% of materials compared to single-phase systems. As a result, three-phase AC power finds wide-ranging applications, and electricity systems around the world commonly employ the three-phase system. Longdistance transmission of three-phase electricity is achieved through cables, which can be classified into single-core single-phase cables and three-core three-phase cross-linked cables.