Eddy-current loss analysis method for permanent magnet wind generators

Abstract

The invention discloses an eddy-current loss analysis method for permanent magnet wind generators. The eddy-current loss analysis method includes the steps of 1), dividing an acquisition mode of eddy-current losses into an MFS single-code coupling mode and an EFEM edge finite element coupling mode according to difference in formation mechanism and component of eddy-current losses; 2), respectively combining component models with the same coupling mode prior to mesh partition; 3), setting unified load for the combined model; 4), performing load transferring on the models established in the MFS single-code coupling mode by an interpolation method, and solving field distribution in staggered iteration through a multi-field solver; 5), solving transient electromagnetic fields and temperature fields by a parallel algorithm; 6), reflecting the electromagnetic fields and the temperature fields of different component models on the corresponding models. An electromagnetic field and temperature field coupling method of single-code two-way coupling analysis and one-way coupling analysis of the edge finite element coupling method are applied to subregional-type acquisition of the eddy-current losses of stator cores, rotor permanent magnets and grooves, and consequently, the eddy-current losses are converted into thermal power and are reflected in temperature field distribution accurately and visually.

Description

technical field [0001] The invention belongs to the field of simulation technology, and specifically relates to an analysis method for eddy current loss in permanent magnet wind power generators widely used in the field of new energy applications, that is, an analysis method for eddy current loss in permanent magnet wind power generators. Background technique [0002] At present, due to the depletion of non-renewable energy and other factors, wind energy has become one of the most promising green energy in the 21st century. With its huge commercial potential and environmental protection benefits, it has been widely valued and developed by all countries in the world. As a sustainable clean energy source, wind power technology has a bright future. This new source of electricity will gradually enter people's homes and eventually become a part of public life. [0003] With the expansion of the application range of small permanent magnet wind turbines, the performance of the moto...

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Problems solved by technology

[0013] From 2008 to 2011, Xing Junqiang’s research team from Shenyang University of Technology, in the research on rotor loss and ventilation and heat dissipation of high-speed permanent magnet motors, approximately believed that the eddy current loss of the rotor was mainly concentrated on the surface of the rotor, and that it was generated by the high-frequency eddy current loss on the surface of the sheath. The eddy current loss in the sleeve is equivalent to the analytical calculation method of a rectangular thin surface under a pole pitch distribution, which can qualitatively analyze the approximate distribution of eddy current loss, but the accuracy is poor

In 2013, Intel Engineering Simulation Technology (Dalian) Co., Ltd. proposed a patent application 201310343818.9 for a method for analyzing the temperature rise and heat dissipation of permanent magnet synchronous motors based on multi-field coupling technology. This patent application applied the multi-field coupling method to permanent magnets for the first time. The temperature rise analysis of the motor has great influence, but the main disadvantage is that the three-field coupling and two sets of models lead to the load loss phenomenon in the load transfer process, and the heat transfer coefficient as the link parameter between the flow field and the temperature field is ignoring the gas The influence of the gap radial speed gradient on it is obtained, and the air gap speed is approximately considered to be the rotor speed, and the convective heat transfer coefficient is calculated by using the traditional empirical formula, so the accuracy of the result is reduced due to the approximation of the intermediate process

In 2013, China Three Gorges University proposed a patent application 201310652717.X for the special-shaped grid mapping method in the coupling calculation of electromagnetic field-flow field-temperature field for the transmission of multi-field coupling load without loss. Solve the data transfer of mismatched grids in the coupling calculation of different physical fields. However, the process of obtaining the correction coefficient is cumbersome and the calculation of the two sets of models consumes a lot of memory. The most critical problem is that the accuracy of the correction coefficient is difficult to evaluate

[0015] The analysis of the above-mentioned existing technologies shows that although the calculation of eddy current loss by the traditional analytical method can be accurately quantified, the equivalent process of the model is ignored and too many assumptions are made, which makes the calculation results deviate greatly from the actual ones; and the two most advanced related Due to the shortcomings of the patented technology, it cannot be applied to the accurate calculation of the eddy current loss of the permanent magnet wind turbine with strong load randomness

Therefore, in order to avoid the inaccurate calculation of the traditional mathematical model and a large amount of calculation work, in order to make up for the shortcomings of the existing coupling technology of the electromagnetic field and the temperature field of the motor, a more variable and variable method suitable for the complex operating conditions of the permanent magnet wind turbine is proposed. Accurate acquisition of eddy current losses must be improved in analytical and technical methods

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