Design And Inductance Calculation Of Brushless Doubly-fed Machine

The brushless doubly-fed machine is a new machine based on the investigation of aself-cascaded induction motor which has the advantage characteristics both asynchronousmachines and synchronous machines. It has two stator windings that are power windings andcontrol windings, and have a cage-rotor or a reluctance-rotor. Because of its robust andmechanical characteristics together with controllable speed and power factor, it usually worksas an AC adjustable speed machine or a variable-speed constant-frequency generator as well.These benefits attract more and more researchers’ attention.Combining with literature review, a detailed introduction and research significance of thebrushless doubly-fed machine are presented, including the origin brushless doubly-fedmachine, its development, current situation, research significance as well as its application.Then based on the principle of brushless doubly-fed machine, briefly analyzing the specificwork circumstances of brushless doubly-fed machine is performed under different operationmodes. The mathematic models of the cage-rotor brushless doubly-fed machine andreluctance-rotor brushless doubly-fed machine in the three-phase static coordinate system areestablished, and the importance of inductance matrix in the mathematic models is pointed out.This thesis researches on motor ontology design of the brushless doubly-fed machine,which content design of the stator structure and the rotor structure. On the basis of the statorstructure design in the traditional asynchronous induction motor and the design requirementsof prototype motor, the design process of brushless doubly-fed machine actual prototypestator structure, which need to master and follow some principles, is introduced. Taking thesalient pole rotor structure design as an example in the part of rotor structure design, thispaper introduces the design procedures of the Taguchi method, establishes the finite analysismodel by orthogonal experiment to find the optimal salient pole rotor structure. Finally someconclusions of the rotor structure design are achieved. In the application of the rotor structuredesign, Taguchi method can improve the design efficiency greatly, and also save time. Themethod can be generalized to design procedure of other type rotors of brushless doubly-fedmachine.The analytical method of inductance parameters of the brushless doubly-fed machines is particularly studied. This paper derives the inductance calculation formula and specificprocedure of the traditional Winding Function Method. On the basis of the traditionalWinding Function Method, an improved Winding Function Method which changes theexpression of winding function and the air gap function is proposed and derived.