DSP-based Inverter Design With Vector Control For Plastic Machine

Nowadays, science technology is changing quickly. Especially, because of the development of computer science, micro-electronics, and modem control theory, electrical machinery and its interrelated subjects develop swiftly and violently. It is feasible and inevitable that digital control method, especially the vector control, has been taking the place of analog control method in this field. Based on widely research about the module of motor and the transform of coordinate, this paper introduces designs of control system to analyze and study digital vector control systems of three phases induct motor in depth. Using digital signal processor (DSP) to control asynchronous motor with space voltage PWM.This paper mainly includes:Introduce the background of frequency conversion technology and the frequency conversion machine market. Some problem will be discussed when the inverter is applied in plastic machine.Introduce the mathematics model of asynchronous motor and the principle of Field oriented control (FOC) and get its vector control equation.Study and analyze digital control to make a detailed discussion about general electrical machines' basic control rules. Introduce the important control technology-pulse width modulate (PWM), especially space vector pulse width modulation (SVPWM), including its principles, sorts and some digital actualization methods in vogueField oriented control (FOC) is based on motor unification principle, energy conversion and vector coordinate transformation theory. It has many advantages such as novelty, practicability and advancement.Using digital signal processor (DSP), TMS320F240, which is special for motor control, we develop one frequency conversion adjustable-speed system which based on FOC principle. The main circuit of the inverter, the detect circuit of current and motor speed, intelligent power module (IPM) and DSP are all presented particularly in this paper. At the same time, new pulse width modulation named space vector pulse width modulation (SVPWM) method is used to control the asynchronous motor. Study the control system of asynchronous motor. Make a detailed discussion about the hardware and software. And get some conclusions through the lots of experimentation analysis.