Cooling System Design And Temperature Field Calculation Of Double Stator Brushless Doubly-Fed Wind Generator

In recent years,the problem of environmental pollution is serious,and new energy technologies are urgently needed to solve this problem.With environmentally friendly,cleanliness,renewable and other aspects of the advantages,the wind energy has become a hot spot in the research of various countries.To solve the low power density,high transportation cost and poor fault tolerance existed in wind turbines,a novel cage-coupled rotor coupled double stator brushless doubly-fed wind generator(DSBDFG)was proposed.Compared with permanent magnet wind turbines and brushed doubly-fed induction generators,the generator has the advantages of high power density,good stability,no demagnetization risk and low maintenance costs,and has a broad application prospect in the field of wind power.However,the complicated structure of the generator leads to difficulty in heat dissipation,which makes the temperature rise is high when it is stably operated.For that,in this paper,a 50 kW DSBDFG was studied and the temperature rise calculation method and cooling system design were researched.It provides a theoretical basis for the subsequent experimental research on this new type of generator,which has certain reference significance.And the main research contents are as follows:Firstly,the overall structure and operating principle of the generator were described.For the calculation of the temperature field of the generator,the three-dimensional physical model and mathematical model were built,the heat generation rate and heat transfer coefficient were calculated.Based on the basic theory of heat transfer,the equivalent thermal network method was used to establish the thermal path calculation model of the DSBDFG.According to the heat transfer relationship of each part,the equations were listed,and the temperature of the internal nodes was calculated.Secondly,water cooling is an effectively way for the reduction of the temperature.The different water cooling structure of the DSBDFG were studied and the velocity distribution,flow resistance and temperature distribution of water cooling systems were analyzed.Different cross-section dimensions were compared.The number of waterways of the spiral structure was studied under the same cooling water flow and water channel area.Then the selection of water channel number for circumferential spiral water cooling structure was studied under the same conditions of the cooling water flow rate.The flow velocity trace,pressure and temperature of the waterway were given,and the effects of different cooling water speeds on the temperature of each component of the generator were analyzed.Finally,a three-dimensional finite element model with cooling system of DSBDFG was established,and the analysis and calculation of the temperature field was presented.The internal temperature rise law of DSBDFG was analyzed.And the influence of different cooling media and casing material on the temperature field of the generator were explored.