Nonlinear pulse width modulation control device of single-phase current source grid-connected inverter

Abstract

The invention relates to a nonlinear pulse width modulation control device of a single-phase current source grid-connected inverter. The device can be used for adjusting duty ratio in time and outputting high quality power grid current by feedback of modulation current, so as to effectively overcome the native defect of serious aberration of power grid current wave form when the traditional linear PWM control strategy is adopted; a control circuit of the device comprises an integrating circuit having high frequency resetting function, an absolute-value circuit I, a comparison circuit, a RS trigger, a combinational logic circuit as well as a reference sinusoidal current circuit, an absolute-value circuit II, a zero-crossing comparison circuit and a constant frequency clock circuit that have fixed phase relationship with the power grid voltage. The nonlinear pulse width modulation control device can lead unstable DC voltage to be converted into stable grid-connected current with the needed magnitude and high quality, and has the advantages of single stage power conversion, high conversion efficiency, small harmonic wave of the grid-connected current, rapid dynamic response, high reliability when in overloading, low cost and the like, so as to establish key technology for a renewable energy source grid-connected power generation system.

Description

technical field [0001] The invention relates to a nonlinear pulse width modulation control device for a single-phase current source grid-connected inverter, which belongs to the power electronics technology. Background technique [0002] Due to the increasing shortage of fossil energy (non-renewable energy) such as oil, coal and natural gas, serious environmental pollution, global warming, nuclear waste and environmental pollution caused by nuclear energy production, energy and the environment have become major issues facing mankind in the 21st century. . Renewable energy (green energy) such as solar energy, wind energy, tidal energy and geothermal energy has the advantages of being clean, pollution-free, cheap, reliable, and abundant. People are paying more and more attention to the development and utilization of renewable energy. The sustainable development is of great significance. [0003] The DC power converted from solar energy, wind energy, hydrogen energy, tidal en...

AI Technical Summary

Problems solved by technology

The circuit structure of this type of inverter must satisfy the peak value of the DC side voltage greater than the AC side voltage when it works normally, so there is an obvious defect: when the DC side voltage (such as the output capacity of photovoltaic cells) decreases, such as rainy days or nights, The entire power generation system will cease to operate and the utilization rate of the system will drop

Therefore, there are obvious defects when the single-phase Boost type grid-connected inverter adopts the traditional linear PWM control strategy, and it is difficult to popularize and apply it in engineering

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