Design And Optimization Of Fault Tolerant Permanent Magnet Rim Driven Motor

With the rapid development of world trade,exchanges between countries become more frequent.As the main transportation route for transnational trade,maritime transportation puts higher requirements on the tonnage of ships.The shafting ship propulsion system occupies a large amount of cabin space and reduce the utilization rate of the ship.With the rapid development of all-electric propulsion system,shaftless propulsion has become possible,and podded propeller has emerged.However,the podded propeller is easy to be failed and difficult to maintain,which reduce the life of the ship.Therefore,a new type of marine propeller,rim thruster,has emerged.At present,the rim thruster do not have fault-tolerant capability.When the rim thruster fails,the ship will lose propulsion power.Therefore,a marine thruster with the capability of fault-tolerance,permanent magnet fault-tolerant rim thruster motor is proposed in this paper to enable the ship to return to maintenanceFirstly,this paper introduces the research status of rim thruster and fault-tolerant permanent magnet motors at home and abroad,and proposes a fault-tolerant permanent magnet rim driven motor.Then,the structural characteristics of the fault-tolerant permanent magnet rim driven motor are analyzed,and the calculation method of the fault-tolerant rim permanent magnet driven motor parameters is given.According to the characteristics of the fractional slot concentrated winding,the possible pole-slot combination and winding distribution of the six-phase fault-tolerant permanent magnet rim driven motor are analyzed.The scheme with the distribution coefficient 1 is further analyzed,and the performance of different pole-slot combination is simulated.According to the design requirements,the basic structure of 36 slots,30 poles is determined.The effects of the polar arc coefficient and centrifugal height of unequal air gap permanent magnets with centrifugal height on no-load back EMF and cogging torque ripple are analyzed.The rotor was optimized and verified by finite element simulation.Based on winding function method,the self-inductance and mutual-inductance of six-phase fault-tolerant permanent magnet rim driven motor are analyzed and verified by finite element simulation.A method of winding reconfiguration which increases self-inductance and decreases mutual-inductance is proposed to optimize the stator.Based on Simplorer,a H-bridge inverter circuit is built and current hysteresis control strategy is used to simulate the operation performance and fault-tolerant capability of six-phase fault-tolerant permanent magnet rim driven motor.Finally,an experimental prototype of six-phase fault-tolerant permanent magnet rim driven motor was manufactured and tested to verify the fault-tolerant capability.The main innovative results of this paper are as follows:(1)According to the characteristics of concentrated winding,the general pole-slot combination scheme and winding distribution structure are given.(2)Based on winding function method,the self-inductance and mutual-inductance of the fault-tolerant permanent magnet rim driven motor are analyzed,and a winding reconfiguration method which can increase self-inductance and decrease mutual-inductance is proposed.