Performance study on high power linear induction motor in transportation

This paper, on the base of the two-dimensional magnetic equations of linear induction motor (LIM), achieves the phase current and excited voltage expressions by dummy electric potential method. Then it deduces the air-gap flux linkage expression by connecting Maxwell electromagnetic field equations, complex power method with conformal transformation method fully considering half-filled slots, york magnetic saturation, back iron resistance. This article, by the equal complex power relationship between magnetic and circuit, obtains some expressions involving excited reactance x_m0, secondary resistance r₂´, secondary leakage reactance x₂, longitudinal end effect coefficients K_r(s) and K_x(s), transverse end edge effect coefficients C_r(s) and C_x(s), skin effect coefficient K_f. Depending on the T-model of rotary induction motor (RIM), this paper presents a new revised T-model equivalent circuit for LIM by superposition theorem. This new model makes calculation for Japanese 12000-LIM in detail. Many curves attained by new model including thrust force, phase current, power factor and efficiency are compared with those of space harmonic method and experience. The contrastive curves and error analysis indicate that this model is credible and accords with engineering application requirement. Therefore, it is so useful that establishes foundation for design and optimization of high-power LIM in transportation.