Design And Simulation Analysis Of The Combined Dual Voltage Permanent Magnet Motor

With the continuous development of the automotive industry, automobilegenerator is no longer just the power of the car whose purpose is not only to supplypower to all electrical equipment in normal operation of the engine. When the car isstarted, the generator operates in motor state having high output torque to get the carquick start, and the whole performance of the automobiles is improved. With theincreasing number of electrical devices on automotive, power is growing and thedemand for automotive electrical power is gradually increased. Therefore, automotivepower supply system needs to have compact structure, high power density, stableoutput voltage, high efficiency, etc. In order to meet this requirements, a kind ofcombined dual voltage permanent magnet machine is designed in this paper whichcould be equivalent that an inner rotor permanent magnet motor is nested into thestator of the outer rotor permanent magnet motor, which the two motors can operatesimultaneously. The machine could generate enough starting torque at low speeds tomeet the required of starting torque. The machine could improve the electricity energyoutput capacity as operating in generator condition and could achieve the dual powersupply. If the machine works in motor condition which could increase the outputtorque and meet the performance requirements of modern automotive motors.The basic theory of the combined dual voltage permanent magnet machineincluding the structure, operation principle, equivalent magnetic circuit model andmathematical model are elaborated in this paper. The coupling effect of inner andouter magnetic field in two kinds of magnetic circuit structures are analyzed whichshows that the coupling between inner and outer air gap flux is small, whether inseries magnetic circuit structure or parallel magnetic circuit structure. By using thefinite element software, the inductance parameters and flux linkage is calculated, thepermanent magnet magnetic field and the armature magnetic field distribution isanalyzed. Theoretical analysis and simulation results are consistent. The combineddual voltage permanent magnet machine having two kinds of magnetic circuitstructures can be equivalent to two independent inner and outer rotor permanentmagnet motors.The electromagnetic design theory and methods of the combined dual voltagepermanent magnet machine are researched in detail, and the relationship between power distribution of the inner and outer motors and the relationship between designparameters are analyzed. Based on the size of inner and outer stator, magnetic circuit,the design of permanent magnet and rotor structure, the electromagnetic design of themachine is finished and the electromagnetic design parameters of the machine arepresented. The performances of the machine having two kinds of magnetic circuitstructures are calculated, which shows that the combined dual voltage permanentmagnet machine has the virtue of high power density, better starting performance,stable output voltage, high space utilization and the composite structure has littleimpact on machine performance. Finally, a method for reducing cogging torque of themachine is presented.