Researchand Development Onac Servo Controlsystem Ofagricultural Electric Vehicle

Cars have become one of the necessary tools in modern society. However, automobile pollute the air, and consume the limited energy. With the development of electronic technology, electric vehicles become an important means to resolve these questions. But the development of technology of the battery limits the driving distance of electric vehicles, and the scrap rate of battery is very high. Design a highly efficiency and low consumption electric vehicle is imperative. With the specialty of highly efficiency, permanent magnet synchronous motor becomes research hotspot in electric vehicle industry. Electric vehicle using in agricultural as one kind of electric vehicles has some particularity. For its complex work environment, vehicle control system needs to have resistance ability to disturbance. In addition, considering the restrictions of rural consumption ability, the cost of agricultural electric vehicles needs to reduce, and this limits the choice of components, and increases the difficulty of design. This issue make agricultural electric vehicle as the researched object, designing a model for permanent magnet synchronous motor as controlled object, outputting smooth sine current and the ability of anti-jamming motor driver.This issue extracted the physical parameters of agricultural electric vehicle, confirming the design parameters of permanent magnet synchronous motor satisfying the sports performance. After manufacturing motor, confirmed practical parameter values of motor. According to the parameter value, confirmed the design parameters of motor driver. In order to provide theoretical basis and experimental reference of the driver system, according to the motor practical parameters built the model of the motor; Based on the space vector control method, built proportion-integral calculators and 2/3 transform calculator model. Using Simulink in Matlab linked module implements, verifying the feasibility of control system, providing theoretical foundation for driver design, and provided reference values for current loop control.Based on the control model of current loop, designed servo controller, the issue facing the limitation of the cost of manufacturing agricultural vehicles, designing the Mosfet circuit driver alternative the module of IPM; Based on the power supply , designed the switching power circuit; According to the function requirements of agricultural electric vehicles, defined pins of NEC 3452 microcontroller, and designed outlying I/O interface circuit according to the motor parameter and software module of current calculation, making the driver output the ampere of instructions . According to the space restrictions of vehicle and the size of the electric components, used Solidworks design shell of driver and assembling the driver. Test the step response and steady-state of agricultural vehicles driver, verifying the good dynamic and static response performance of driver.Based on the agricultural vehicles driver, this issue analyzed the optimization method of current output performance of driver. Theoretically proved the good resistance to disturbance of the IP current loop control structure. Used Matlab compare the resistance to disturbance between PI and IP control structure structures, verifying the results; Analysed adverse impact of the error output of current, confirming error part of output current. According to zero-point drift of current sensor, amended the algorithm, solving the deviation; Introduced current state observer, and solved the error caused by delay of voltage calculation. Amended the algorithm, and solved the error caused by calculating delay and the mechanical installation error of the encoder; Amended the algorithm, and solved the current wave caused by settings of Mosfet dead zone and the change of motor speed.This issue designed the driver of agricultural electric vehicle, achieving the desired design parameters, and proved the validity of the optimization algorithm for torque control through experiments, realizing the optimization torque control of motor.