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A method for calculating temperature field of multi-turn densely wound coil by combining thermal resistance network method with finite difference method

A finite-difference method and densely wound coil technology, which is applied in the calculation field of fast solution to the temperature field of two-dimensional axisymmetric coils, can solve problems affecting life and reliability, inter-turn short circuit, affecting the insulation effect and life of enameled wire insulation varnish, etc.

Active Publication Date: 2019-02-22
HARBIN INST OF TECH
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Problems solved by technology

Excessive temperature rise will also affect the insulation effect and life of the enameled wire insulation varnish layer, resulting in inter-turn short circuit and other situations, affecting its life and reliability
In the past, the assumption of uniform internal temperature distribution and the assumption that the coil winding part is made of pure copper because it is difficult to measure the internal temperature of the coil are not suitable for the needs of more accurate calculations.
Therefore, a new calculation method is needed to solve the problem of insufficient calculation accuracy of the temperature rise of multi-turn densely wound coils

Method used

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  • A method for calculating temperature field of multi-turn densely wound coil by combining thermal resistance network method with finite difference method
  • A method for calculating temperature field of multi-turn densely wound coil by combining thermal resistance network method with finite difference method
  • A method for calculating temperature field of multi-turn densely wound coil by combining thermal resistance network method with finite difference method

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Embodiment

[0049] Calculate for the inner coil of a certain type of contactor.

[0050] The outer diameter of the coil skeleton is 46mm, the diameter of the copper wire is 0.35mm, the outer diameter of the paint layer is 0.4mm, and there are 2100 turns in total. The coil resistance is about 37.5Ω at room temperature, and the voltage is 28V at both ends, and the initial power is P 0 About 20.91W. The thermal conductivity of the material is assumed to be a constant that does not change with temperature, but as the temperature increases, the resistivity of the copper wire will change, which in turn will affect the power at steady state. Copper wire resistivity ρ changes with temperature rise τ reference formula: ρ=ρ 0 (1+0.00393τ), where: ρ 0 is the resistivity of the material when the temperature rise is zero. Power in steady state: P=P 0 / (1+0.00393τ). The arrangement of the copper wires is judged to be aligned, and the thermal resistance network refers to image 3 , the average di...

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Abstract

The invention discloses a method for calculating the temperature field of a multi-turn close-wound coil by combining a thermal resistance network method and a finite difference method, A numerical method for calculating the temperature field of multi-turn densely wound coils is presented in this paper, which combines the idea of equivalent heat path with the finite difference method. The method takes into account the effects of material properties such as copper wire, insulating paint, air, wire diameter, paint thickness, wire-to-wire distance and other dimensional parameters on heat transfer.The model is in good agreement with the actual coil. A method for quickly and accurately sol that temperature field of coil combines the idea of the thermal resistance network method and the finite difference method, The calculated temperature in the coil is high and the temperature difference at the low point is tens of degrees Celsius, which accords with the actual temperature distribution of the multi-turn close-wound coil working for a long time and replaces the incorrect temperature distribution obtained by the previous method. The solution error is less than 8.5%.

Description

technical field [0001] The invention belongs to the field of electrical numerical calculation, and relates to a calculation method for quickly solving the temperature field of a two-dimensional axisymmetric coil by combining a thermal resistance network method and a finite difference method. Background technique [0002] Multi-turn densely wound coils are often used in switching appliances such as relays and contactors as a source of electromagnetic driving force. This type of coil has a large number of turns, usually more than a thousand turns. Since the multi-turn enameled wire is closely wound and the current passes through it for a long time, the multi-turn coil is usually one of the main heat sources of this type of mechanism, and the temperature rises after a long time of work. With the use of new energy sources, high-power switching appliances are widely used in electric vehicles, charging piles and other occasions for connecting high currents. The power demand of su...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06F17/50
CPCG06F30/20
Inventor 杨文英李茹瑶邱子澜王茹翟国富
Owner HARBIN INST OF TECH
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