Design On The Current Loop Control Of AC Servo System Based On FPGA

With the continuous progress of the field programmable gate array (FPGA)technology, AC servo drive technology based on FPGA gets more and more attentiongradually by high running speed, flexible interface, good portability, et al. Based onanalysis of the research literature, the thesis focuses on the hardware design method of thecurrent loop control of ac servo system based on FPGA, aiming to improve the currentloop control performance of the servo system which restricts the response of the servosystem seriously.Firstly, based on the mathematical model of the permanent magnet synchronous motorand the basic principles of vector control, the current decoupling control method isanalyzed in the thesis, a complex vector current regulator stategy is designed to improvethe application performance. Simulation works are done to prove it in MATLAB/SIMULINK environment.Then, the characteristic of structure of Cyclone II series FPGA is discussed, and thehardware design of FPGA-based servo system, especially the power supply circuit andconfiguration circuit of the FPGA are given to adapt requirment.Through description of the FPGA development process based on Quartus II software,a detailed design method and idea of each module in the FPGA-based AC servo systemare introduced, which include the timing scheduling module, the vector transformationmodule, the current regulator module, the space vector PWM module, current sensorinterface module, encoder feedback signal processing module, et al. And some timingsimulation results are given.Simultaneously, the method of multi-axis synchronous motor current loop controlscheme is analyzed in the thesis. A key scheme of timing scheduling based on pipelinestructure in the multi-axis synchronous motor current loop control was described in detail,which consumes short computation time without increasing the hardware resources ofFPGA.Finally, the experiment result of the FPGA-based current loop control was given. Bycomparing the performance of traditional DSP software-based AC servo with theFPGA-based AC servo, the advantages of the FPGA is verified. Besides, the experimentanalysis of the complex vector decoupling control method was given.