Based On The Three-level Inverter, Induction Motor Vector Control System

At present, the three-level topology of occasions in the application of high-power is more widely. Research and development of high-power three-level inverter has great significance in terms of technical or practical applications. In this paper, three-level inverter's modulation strategy, control method, bus communication and the design of entire system are analyzed and researched.In the high-power and high-voltage applications, switching losses of the inverter's switching device occupy the main position in the total loss. So it is not only necessary to guarantee the waveform quality and reduce the harmonic content, but also necessary to reduce the switching losses to improve the reliability of devices .These issues become foremost problem to be solved, but the resolution of these issues can not simply rely on reducing the carrier frequency. In this paper, a specific harmonic eliminate technology was introduced and researched on the harmonic elimination equations and the choice method of initial value. Experimental and simulation results show that the method not only eliminates the low harmonics, but also reduces the switching losses. So it has great advantages in high-power applications.Vector transform control technology is a high performance AC motor control methods. This paper elaborated on the basic principles of vector control systems and gave a basic block diagram of vector control. Then it carried out a detailed analysis on the key technology about the flux estimated and the regulator design. And the simulation and experiment of three-level vector control system was carried out.In order to achieve network-based inverter control, this paper, based on C8051F020 MCU, developed an PROFIBUS-DP slave based on a greement with Siemens SPC3 chip. The interface controller can realize the seamless internet between PROFIBUS Field-bus and converter.Finally, a 660V/600KW high-power medium voltage vector control inverter was developed. This paper carried out a detailed analysis and presentation on the main circuit and control circuit of the hardware design and software design. Finally, the experimental results show that the output waveforms of inverter have a good performance to meet the requirements.