Study On PWM Realization Method For Three-phase Inverter

Three-phase Inverter using PWM technology is applied widely in the many industry fields, such as motor control, UPS, electronic power quality control technique and so on, for its excellent performance. There are several tradition PWM Realization Methods for Three-phase Inverter, but they also have the disadvantages of exclusive and not flexible. Hunting for the method with characters of flexible, economical, general purpose and easy to extend is important to meet the need of application.Focusing on PWM Realization Method for Three-phase Inverter, a PWM realization scheme which use DSP and CPLD chips to realize the control system is proposed. Software and hardware design of the system is discussed in detail. All algorithms are implemented using C language in DSP chip. Focusing on realization though program, Two-level and three-level SVPWM theory are expounded in this thesis. At the same time, a general PWM algorithm that can induce several PWM algorithms in program realization by changing a few parameters is summarized.In the system, two-level PWM signal generator with six PWM signal output channels is realized using VHDL language and CPLD chip. Taking advantage of CPLD chip's characters, the generator is extended to three-level Sub Harmonic PWM signal generator with twelve PWM signal output channels. Five-level Carrier Phase Shifting PWM signal generator with twenty four PWM signal output channels can be obtained in the same way.The correctness and feasibility of the proposal are verified by the results of simulation based on software environment. On the orther hand, the fact can also be proved by the waveforms observed by oscillograph.