Research And Design Of The Electric Forklift AC Induction Motor Vector Control Sestem

With the energy, environmental issues becoming increasingly prominent, electric forklift gradually instead of the traditional forklift. Domestic electric forklift has the very high research value and broad market prospects, and core of the electric forklift truck is the control system, so the research on the forklift control system having the realistic economic and social benefits.The main topic is to research and design a practical application of electric forklift induction motor vector control system. Firstly, the thesis introduces the model of the induction motor on the three-phase stationary reference frame and the concept of space vector, derives the model of the induction motor on the two-phase stationary reference frame and two-phase rotating coordinate frame through the transformation of the coordinates, and then it explains the basic theory of the vector control and the algorithm of rotor flux oriented control. The main topic is to research and design a practical application of electric forklift induction motor vector control system. Firstly, the thesis introduces the model of the induction motor on the three-phase stationary reference frame and the concept of space vector, derives the model of the induction motor on the two-phase stationary reference frame and two-phase rotating coordinate frame through the transformation of the coordinates, and then it explains the basic theory of the vector control and the algorithm of rotor flux oriented control. Then, for the dead zone effects of the traditional SVPWM modulation method, in-depth analysis of traditional SVPWM and mixed vector modulation, designed the new no dead zone SVPWM Modulation and the modulation method does not need to set the dead zone. Solve the dead-time effect in the traditional SVPWM modulation methods lead to waveform distortion, completely avoid the fundamental problem of the dead zone, without distortion of the output waveform of the inverter AC side, good sine degrees, a detailed analysis of the method principle and method, andbuilding simulation in Simulink to verify the correctness of the method.Secondly, the system hardware and software design, including the main circuit power design, the drive circuit design, control circuit design and system software design. The main circuit analysis of the basic characteristics of the MOSFET, the MOSFET in parallel flow characteristics were analyzed, and in the saber simulation environment building simulation and analysis of parallel with MOSFET flow characteristic. Design of the aluminum palte with a buffer circuit technology the main circuit power board, and gives a theoretical derivation of the buffer circuit component parameters formula and the aluminum palte design requirements. Drive circuit design mainly adopts opto-isolation and push-pull circuit drive, both isolated shield to increase the anti-jamming capability, the safe operation of the security system, but also to meet the switching speed and drive capability. Designed TMS320F28335as the core control circuit and software system.Finally, Introduced indirect rotor field oriented vector control system, designs the current control loop and the speed control loop of the control system, build the Simulink simulation of vector control system, simulation results show that the control system has good dynamic response and steady state accuracy. And in building hardware platform, driven circuit, buffer circuit and vector control system of the experiment. The experimental results show that:the new SVPWM modulation drive to good effect, a significant improvement of the buffer circuit to the driver signal, the system is running stable, good dynamic performance, meet the design requirements.