Study On Axial Sectional Claw Pole Machine With Permanent Magnet Outer Rotor

Novel axial sectional claw pole machine with PM outer rotor (ASCPM) has caused wide concern because of high torque density, simple structure and low cost. It acts not only as an adjustable velocity electric machine to be applied in electrical drive system but also as a generator to be applied in car, water power and wind power. Study on ASCPM is still at an elementary stage at home and abroad, due to lack of analysis theory and design method about this kind of machine at present, the systemic research works are done from the starting of the basic electromagnetic relationship under the supports of creative group project from education office of Liaoning province and international cooperation project with Trimerics Gmbh of Germany.Firstly, analytic theory and electromagnetic model about ASCPM have been studied systematically. In comparison with conventional claw pole machine, its structure of stator and rotor and magnetic circuit are different, the existing analysis model and method are no longer adapted for this machine. Therefore, basic electromagnetic relationship and principle of electromechanical energy conversion about ASCPM are analyzed; and soft magnetic composite material (SMC) used in rotor claw pole is described; the characteristics of material and performance comparison with silicon steel sheet is presented; Models of equivalent magnetic circuit, electrical circuit and thermal circuit about ASCPM are created; calculation equations of reluctance and thermal resistance of key segment are derived; the design simulation procedure is developed and the simulation research is done under the different operating conditions.Secondly, parameters of electric machine are research foundation of operating characteristics, in order to acquire the parameters of ASCPM correctly, magnetic analysis about ASCPM is done. By means of three dimension (3D) finite element analysis (FEA) method, no load electromotive force and air gap magnetic flux density distribution are studied; the reactance, equivalent coefficient of air gap magnetic flux density and equivalent leakage magnetic coefficient about ASCPM are studied deeply; Leakage flux of this machine is complex, through the computation of leakage flux, the errors caused by approximate treatment in magnetic circuit model are amended.Thirdly, torque density and cogging torque are studied deeply. Analytical formulas of torque density and cogging torque are deduced respectively; formulas are verified by means of 3D FEA method. The methods of decreasing the cogging torque about ASCPM are put forward.Fourthly, due to immaturity of control methods about ASCPM, Mathematic models of the transfer function and differential equation of ASCPM are established; the control system of electric machine is designed; the simulation researches operated as a motor and a generator are done by means of simulation model. On the basis of theory and simulation research, the control strategy is brought forward.Finally, based on theoretical research above, design characteristic and design procedure are put forward. A 1.5kW 12-poles prototype of ASCPM is designed and manufactured; the whole performance test of this prototype is completed; Correctness and feasibility of design and analysis method mentioned are verified through the comparison of experiment result and theory analysis, foundation of theory and technology is laid on further research on this kind of machine.