A Design Of A Polyurethane Coating Spraying Machine And A Research On Variable-frequency Speed Control Systems Based On DSP

A Polyurethane Coating Spraying Machine using air mixed spraying method is designed in this paper. The principle of its hydraulic system is described in detail and the major components of the hydraulic system are properly chosen. The variable-frequency speed control system of the spraying machine is also designed in this paper. A suitable transducer and major electronic components are selected for the control system. Additionally, the design of the structure of the spraying machine is briefly introduced.To have further research of the principle and performance of variable-frequency speed control system, a variable-frequency speed control system based on TMS320LF2407DSP is designed in the paper. The main circuit of the control system adopts uncontrolled rectifying circuit and full-bridge inverter circuit using PWM. The selection methods of electronic components in rectifying circuit, filter circuit and inverting circuit are given. The control system includes the minimum system with the TMS320LF2407DSP as a hardware core, the detection circuit, the keyboard and display circuit. Some necessary chips and hardwares of the control system are chosen. Meanwhile, the circuit diagrams are shown in the paper.For the realization of the hardware circuit’s function, reliable software program is designed. The program flow charts are given.Finally, the simulations of open loop Variable-Voltage-Variable-Frequency speed control system and closed loop Variable-Voltage-Variable-Frequency speed control system are performed respectively. Some reasonable analysis of the result of the simulation is given in the paper.