Research For The Overheating Protection Strategy Of Wheel Drive Motor Based On The Temperature Forecast

Wheel drive motor has many advantages, like high efficiency of transmission,flexibility of control, reliability of operation, light mass and so on. It is applied in automotivemore and more widely. It could not only let automotive avoid to use lots of transmissionsystem, but also let automotive realize many driven styles. Because of the bad workingenvironment relatively and the changeable with complex working condition, the wheel drivemotor is easy to get a high temperature inside, which cause the performance of permanentmagnet to reduce, the ageing of accelerated enameled wiring, the performance of motor toreduce finally.The protective devices, like relay, fuse and electric device are popular in overheatingprotection for wheel drive motor, when the unusual behavior occurs in motor, the powersource is turned off, to protect the motor. Now, there is one advanced method about limitingpower, when the motor is overheating, the limiting power method is utilized to protect themotor. These methods use passive protection approaches. The motor is overheating, whichmain reason is the current is too large, in this thesis, the condition of that the wheel drivemotor is locked rotor, to study the overheating protection for wheel drive motor.In the condition of locked rotor, the temperature of wheel drive motor is caused bycurrent mainly, in this thesis, the current limitation method is utilized to protect motor.Because the temperature rising of wheel drive motor is a delay process relatively, to get abetter overheating protection to wheel drive motor, the actively predictive temperaturechange method and protective motor method in advance are chose to use in the thesis.To build accurate predictive temperature rising model, this thesis use equivalent heatroute method to get lower accurate predictive temperature rising model, by mathtransformation of acquired model, the problem of getting a predictive temperature rising model is transferred into the problem of calculating an optimal solution.To realize the on-board protection on motor, the predictive temperature rising modeland overheating protection method model are needed to call out frequently. This not only risethe complexity of control system, but also reduce the flexibility and instantaneity of controlsystem causing by heavy calculation. At the same time with rising the instantaneity ofsystem, to manage the order of callout among tasks, this thesis choose to divide the biggertasks into several smaller tasks, and manage the callout proceeding of these tasks byμC/OS-II operation system.Through the simulation on predictive temperature rising model and overheatingprotection method model, the validity of predictive temperature rising model andreasonability of overheating protection method model are testified. By experiments on builtwheel drive motor testing platform, the validity of predictive temperature rising model andreasonability of overheating protection method model are testified again. These benefit thefollowing study on wheel drive motor overheating protection in other working conditions,and also build the fundamental on the study of wheel drive motor technic in some way.