Research On Performance And Winding Design Of Wound-Rotor Brushless Doubly-Fed Machine

The Brushless Doubly-Fed Machine (BDFM) shows commercial promise as a variable speed drive or generator. However, for this promise to be realised the design of the machine must be improved beyond that proposed to date. This dissertation contributes towards this goal through machine analysis, winding design and performance research.The Brushless Doubly-Fed Machine (BDFM) is a novel AC induction machine. The BDFM can achieve multiplicate operation mode, such as asynchronous, synchronous and doubly-fed operation mode. The BDFM avoids the use of brush and slip ring and has some advantages, such as simple structure, robustness, reliability, adjustable power factor and a fractional rated converter. It will have wide application in the control-frequency saving-energy adjustable speed drive (ASD) systems, such as fan and pump load drives, and the constant-voltage constant-frequency (CVCF) variable speed generation (VSG) systems, such as ship shaft generator, water power and wind power generation.The key factor affecting the performance of the BDFM is the rotor structure. The rotors of domestic and foreign BDFM have mainly adopted the'nested-loop'and reluctance structures at present, but the'nested-loop'and reluctance structures have some disadvantages, such as low conductor utilization ratio and abundant harmonic contents of the rotor. Compared to the'nested-loop'and reluctance rotor, because the wound rotor studied in this dissertation has a flexible connection, and makes the winding conductor utilization ratio high and harmonic contents low by rational design, adjustment and control, wound-rotor BDFM has better performance index and practicability.With the object of wound-rotor BDFM, the research aims to study the theory of wound-rotor BDFM in depth, develop the effective wound-rotor winding design means, write the convenient reliable rotor winding design calculation program, develop the electromagnetic design means and accelerate the utilization progress of wound-rotor BDFM.The main content of this dissertation is summarized as follows:First of all, the background conditions, the development of the history and current situation of new type wound-rotor BDFM are reviewed briefly, especially it expounds the research significance new Wound BDFM, Also it shows the application prospect in the marine and wind power. Then the basic principle of BDFM, the stator and rotor winding structure and the operation mode are introduced. Secondly, the Magnetic Motive Force (MMF) harmonic analysis method of the BDFM is put forward, the rotor windings analyzing software is compiled, and the harmonic leakage reactance and the rotor slot leakage reactance analysis are given. Based on the slot number phase diagram, the single-winding magnetomotive force harmonic theory, the slot harmonic principle and the characterization of MMF harmonics reduced by distributed winding, the BDFM rotor winding design method is presented .And examples of several specific winding design are given. Reference the star - delta connection winding of stator windings may be increase the winding coefficient, the star - circle connection design method of rotor winding is proposed, and the connection principle and the motor winding connection instance are given.Thirdly, the basis for rotor slot cooperated with stator slot of BDFM and choice poles are given. Also the effect for motor performance as motor choice diffient poles is given. The effect of the electric load and magnetic load on the main dimensions design for the new type wound-rotor BDFM is analyzed. Further in the extent permitted of electric load and magnetic load, the condition to minimize the motor size and increase the BDFM power density is analyzed. The parameters mensurate for BDFM circuit is an important method for verify the theory of motor parameters. In this paper, the prototype experimental data is anslysised by an improved particle swarm optimization algorithm and the multiple sets of optimization data are gotten, the data given suport for motor design.Finally, based on two sets Y315 motor, seven winding schemes of 4 / 8 pole motor have been designed, the application of prototype in the marine is analyzed as follows: the prototype magnetic field saturation almost invariant is verified as the prototype control winding work at different frequencies by no load experiment; the changing process of prototype working state in a variety of load conditions is analyzed by load experiment; the relation of the frequency inverter capacity and the speed is given by analyzing different prototype schemes; the efficiency and its trend under different loads or different speed are verified by analyzing prototype parameters; the scope of the reliable operation of the prototype is given by analysis electric load and magnetic load of prototype; it is analyzed that the rotor slot combining with stator slot of prototype effect on motor vibration by measuring the different schemes.