The Development Of AC Inverter And Its Control System

With the rapid development of the technique on the electric power and the microelectronic circuit with the progressive improvement of the theory about computer AC electromotor control, the transmission technique on AC electromotor advanced rapidly and the trend to supersede DC traction transmission came forth. Thus the AC transmission technique is in wider and wider use in related fields such as orbital vehicles. This paper introduced the circuit of inverter control based on single-chip computer 80C196KC and SA4828 and it applied in different control mode of three-phase induction motor. The circuit can produce wave PWM not only by SA4828 but also by microcontroller program.Basic techniques of VVVF are introduced, such as inverter work principle of motor under VVVF control, fundamental theories which Sinusoidal Pulse-Width Modulation (SPWM) control algorithm are based on, and macrocomputer unit (MCU) realization of SPWM, etc. Software and hardware used in this design are specified, aswell as the resulting design of main circuit, protecting circuit and control circuit for the system.Parameter calculations of inverter, driving circuits of Insulated-Gate Bipolar Transistor (IGBT), and peripheral circuits are discussed in the design of main circuit Efforts are made to increase system safety, such as designing of a protecting circuit. Design theory and important parameters of the protecting circuit are described In the control circuit, microcomputer is used for realizing SPWM algorithm. This controller is chosen to provide real time control.Electromagnetism Compatibility (EMC) of digital system is also discussed in this paper. A design method of hardware and software, protection circuit and crosstalk reduction is proposed. A reliable system is developed and verified.