Control method for canceling specified harmonics of three-level midpoint clamp photovoltaic inverter

Abstract

The invention discloses a control method for canceling specified harmonics of a three-level midpoint clamp photovoltaic inverter. The control method comprises the following steps of: firstly, establishing a mathematical model of the control method for the specified harmonics of the three-level midpoint clamp photovoltaic inverter and solving the following nonlinear transcendental equations; secondly, establishing a midpoint current mathematical model of the three-level midpoint clamp photovoltaic inverter; and thirdly, solving by adopting a continuous space ant colony algorithm. According to the control method disclosed by the invention, the control method for canceling the specified harmonics of the three-level midpoint clamp photovoltaic inverter is combined with midpoint voltage balance; the midpoint voltage balance can be effectively controlled while the specified low-order harmonics are canceled, so that an output waveform is greatly improved and the total harmonic distorsion is reduced.

Description

technical field [0001] The invention relates to a specific harmonic elimination control method for a three-level midpoint clamp photovoltaic inverter. Background technique [0002] The specific harmonic elimination control method of the three-level neutral point clamped photovoltaic inverter properly controls the pulse width modulation voltage waveform of the inverter through the optimal selection of the switching time, so that there are no certain harmonics in the output voltage of the inverter. Specific self-lower) harmonics. [0003] The difficulty of the specific harmonic elimination control method is mainly that it must solve a set of nonlinear transcendental equations. The traditional method is to use the Newton iterative method. This method requires a set of initial values ​​to solve the nonlinear equations. The selection of the initial value is appropriate and Whether or not directly determines whether the algorithm converges, so the selection of the initial value s...

AI Technical Summary

Problems solved by technology

There is no systematic and effective method for selecting the initial value, and researchers generally use the trial and error method, which is very inefficient

And the traditional specific harmonic elimination control method only starts from the perspective of eliminating specific low-order harmonics, without considering the overall performance of the photovoltaic inverter

For the three-level neutral-point clamped photovoltaic inverter, while eliminating specific harmonics, the key technical issue of the three-level neutral-point clamped inverter-the neutral point voltage balance problem is not considered

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