Control Strategy Research And Application Of Harmonic Generator Based On Selective Harmonic Elimination

Since the 1970s the 20th century, along with the rapid development of power electronics technology, especially the semiconductor devices and the power converter technology, Large-capacity power rectifier, power converter equipment and non-linear load are widely used in power system. That made the Power harmonics become increasingly serious pollution problems. All kinds of breakdowns and accidents caused by harmonics has been produced, harmonics caused a high degree of concern about the serious harm. Research on the issue of power system harmonics gradually coming to attention. In engineering practice and theoretical analysis, harmonic signal analysis and processing is a very important significance. Harmonic signal generator as a source supplies a basic condition for practical and theoretical analysis.This paper introduces the structure and generation principle of several common harmonic generators. According to the structure of each generator, the advantage and disadvantage are discussed. Then, harmonic generator based on SHEPWM (Selective Harmonic Elimination), especially its Principle highlights. The issue turns to key problems on application of SHEPWM generator: the control signal should be created by solve complex nonlinear equations.The core issue on SHEPWM generator is solving the complex nonlinear equations quickly and accurately. This paper introduces the homotopy algorithm and the Newton method, and a new method based on tangent sampling, which is used to confirm the initial values is given.Equipment has been designed to verify the reliability of SHEPWM harmonic. The hardware and software were introduced in this paper. A lot of experiment data prove this equipment's effect, the structure and working principle based on SHEPWM lead the harmonic generator to have more flexible, more controllable and wider output characteristics.