Hybrid driven low harmonic inversion control method and modulation mode switching circuit thereof

Abstract

The invention discloses a hybrid driven low harmonic inversion control method and a modulation mode switching circuit thereof. An inversion control technology of monopolar modulation and ambipolar modulation is used in one sinusoidal period in a mixed way, the ambipolar modulation is used in intervals before and after the zero crossing point of the sinusoidal period, and the monopolar modulation is used in other intervals of the sinusoidal period, the time ratio of the monopolar modulation to the ambipolar modulation in one sinusoidal period is controlled by setting different control parameters, under the condition of the same control parameter and circuit parameter, and the voltage or current harmonics output by the inverter can be effectively reduced. The invention is especially suitable for the grid-connected inverter control in renewable energy sources.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and relates to a modulation mode switching circuit in low-harmonic inverter control of a hybrid drive. Background technique [0002] The technology of converting DC to AC is called inverter. In order to obtain pure sine wave output and reduce harmonics in output voltage or current, SPWM (Sinusoidal Pulse Width Modulation) modulation technology is widely used in inverter in control. With the increasing demand for energy in modern society, the available primary energy such as coal and oil is less and less, and the waste gas and waste generated in the process of coal and oil utilization are seriously polluting the natural environment, which is harmful to human health and Life does a lot of harm. In order to avoid energy crisis and protect the environment, people began to use renewable energy. Therefore, distributed power generation systems using renewable energy are developing rapidly. ...

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Problems solved by technology

[0004] During the actual application of unipolar SPWM and bipolar SPWM, the output waveform of the inverter will be distorted to varying degrees due to the limitation of its inherent characteristics, and the unipolar modulation will make the inverter output Distortion occurs near the zero-crossing point of the sine wave, and bipolar modulation will cause the inverter output to be distorted near the sine peak value. Both of these distortions will increase the harmonics of the output voltage or current and affect the quality of the inverter output AC power.

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