One Bus EHPS Control System Based On The ACS24XS Motor Driver

This study focused on new energy electric buses (including pure electric buses andhybrid buses).By researching the power steering system of the current new energy electricbus, it is found that the electro-hydraulic power steering system (EHPS) the current newenergy electric buses apply mostly utilize high-voltage and constant speed operation mode,which leads to serious energy loss and the steering power can not be further preciselycontrolled, the security and stability need to be improved. For these reasons, this paperimproved the current bus EHPS system, and selected the ACS24XS motor driver to controlthe motor speed in real time. Through controlling the motor speed in real time, the steeringpower can be more precisely controlled and the energy consumption will be further reduced.For the shortcomings of the EHPS system in the current new energy electric buses, thispaper firstly presents the improved program, and introduces the background, structures,technical implementation program, working principle, specific control program andadvantages of the new energy electric buses EHPS systems of this study.Secondly, the bus EHPS system is divided into the motor module, mechanical module,hydraulic module and motor control module, each is established mathematical model, whilebuilding two degrees of freedom model of vehicle. On the basis of the mathematical model,the simulation model of each part of the system is established by Matlab/Simulink, andfinally the Matlab simulation model of the EHPS system is established up combined with thevehicle model.Then the values of various parameters are ascertained in the model，laying thefoundation for the simulation analysis research．In this paper, the following four aspects simulation analysis of the bus EHPS system areconducted. Using the established AC servo motor simulation model which is well controlledby two-closed-loop control method， the motor control section is analyzed, and therelationship of AC motor speed and current between the simulation and actual data werecompared to verify the correctness of the AC motor model and its response characteristicsand work stability; the steering power characteristic of the bus EHPS system under differentspeed and different steering wheel angular speed is analyzed; the simulation of the impact ofthe bus EHPS system on the vehicle handling and stability is conducted; under the differentspeed and different steering wheel angle input speed, the impact of the bus EHPS systembefore and after improved on the vehicle handling and stability is comparatively analyzed. This study provides a certain basis for further improving the characteristics of bus EHPSsystem and enhancing bus handling, stability and security, it also provides a theoretical andengineering basis for the optimum design and development of the follow-up bus EHPSsystem.