AC bypass single-phase photovoltaic inverter and its control method and control device

A photovoltaic inverter and AC bypass technology, applied in photovoltaic power generation, single-network parallel feeding arrangement, etc., can solve problems such as current zero-crossing distortion

Active Publication Date: 2017-02-15
SUNGROW POWER SUPPLY CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The current AC bypass single-phase photovoltaic inverter has the problem of current zero-crossing distortion during operation

Method used

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  • AC bypass single-phase photovoltaic inverter and its control method and control device
  • AC bypass single-phase photovoltaic inverter and its control method and control device
  • AC bypass single-phase photovoltaic inverter and its control method and control device

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Embodiment Construction

[0077] The grid-connected working principle of the photovoltaic inverter can be equivalent to: a phase-controllable current source After a reactor L (its internal resistance can be ignored) and a voltage source injected into the AC grid, such as image 3 shown. To ensure that the grid voltage and the grid-connected current are in phase, the voltage generated by the current source at the front end of the reactor L To lead the grid voltage This ends up with the voltage across the reactor The resultant vectors are in-phase, as Figure 4 shown.

[0078] Voltage The phase of the grid is determined by the modulation wave, and the current modulation wave is output according to the phase of the grid voltage. However, due to various factors such as PI modulator and discretization, the phase of the modulated wave lags behind the phase of the grid voltage, so that the advanced phase of the modulated wave cannot meet the requirements, and the grid-connected current cannot be ...

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Abstract

The invention discloses an alternating-current bypass single-phase photovoltaic inverter and a control method and control device thereof. In the method, closed-loop adjustment is carried out on the phase of modulating waves according to the phase difference between a grid-connected current signal and a grid-connected voltage signal so that the phase difference with a certain fixed value can be kept between the grid-connected current signal and the grid-connected voltage signal; the phase of the grid-connected current signal is locked to control an alternating-current bypass power switch tube so that switching of the alternating-current bypass power switch tube can be achieved during zero crossing of a current. The grid-connected current is not interrupted, the zero crossing distortion of the current is reduced or even eliminated, and a reactive current with any angle can be generated by an alternating-current bypass single-phase photovoltaic inverter. The invention further discloses the alternating-current bypass single-phase photovoltaic inverter.

Description

technical field [0001] The invention belongs to the technical field of inverters, and in particular relates to an AC bypass single-phase photovoltaic inverter, a control method and a control device thereof. Background technique [0002] Photovoltaic inverters using non-isolated (transformer-free) topology have high efficiency, small size, light weight, and low cost. These advantages have been valued by photovoltaic inverter manufacturers and research institutions, and a large number of related research results have appeared. The earth has promoted the development of photovoltaic power generation technology. However, a photovoltaic inverter using a non-isolated topology can form a direct electrical connection with the AC grid. This electrical connection can form a high-frequency common-mode voltage from the high-frequency common-mode voltage generated by the switching of power devices, resulting in conduction and radiation interference. problems and safety hazards. [0003]...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/38
CPCY02E10/56
Inventor 李俊陶磊张兴赵为
Owner SUNGROW POWER SUPPLY CO LTD
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