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Photovoltaic grid-connected control method and system based on wave trap and proportional resonance controller

A proportional resonance and control method technology, applied in the field of power systems, can solve problems such as aggravation of grid imbalance, DC side overvoltage, grid power fluctuations, etc., to improve safety and stability, and to solve voltage fluctuations and output power distortion. , the effect of parameter easy

Active Publication Date: 2020-05-22
CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Especially during asymmetrical faults, there are problems such as DC side overvoltage and grid-connected power distortion, which will lead to grid power fluctuations and even further aggravate the grid imbalance

Method used

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  • Photovoltaic grid-connected control method and system based on wave trap and proportional resonance controller
  • Photovoltaic grid-connected control method and system based on wave trap and proportional resonance controller
  • Photovoltaic grid-connected control method and system based on wave trap and proportional resonance controller

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Embodiment 1

[0058] Such as figure 1 As shown, this embodiment discloses a photovoltaic grid-connected control system based on a wave trap and a proportional resonance controller, including a positive and negative sequence separation model, a current control model and an inverter control model with harmonic suppression;

[0059] The output terminals of the positive and negative sequence separation model and the current control model are connected to the input terminal of the inverter control model with harmonic suppression;

[0060] The positive and negative sequence separation model calculates the positive and negative sequence components of the grid voltage (that is, the grid-connected point voltage of the photovoltaic power generation system, which is the measured value);

[0061] The input terminal of the current control model is connected to the output terminal of the voltage amplitude signal; the current control model calculates the active and reactive current reference value of the ...

Embodiment 2

[0065] In this embodiment, on the basis of Embodiment 1, the photovoltaic grid-connected control system also includes a maximum power point tracking model; the photovoltaic array is connected to the grid through a boost circuit and an inverter in turn; the output port of the maximum power point tracking model is connected to the photovoltaic array Step-up circuit (Boost circuit) connection;

[0066] If no grid voltage drop is detected, the active power priority control method is adopted to perform MPPT control on the photovoltaic array based on the maximum power point tracking model, that is, the PWM wave generated by the maximum power point tracking model drives the boost circuit of the photovoltaic array to maintain the maximum power of the photovoltaic array. Power output; the active current reference value I is obtained through the voltage outer loop dref , reactive current reference value I qref Set to zero, the inverter output voltage reference value U of the current in...

Embodiment 3

[0070] Such as figure 2 As shown, this embodiment discloses a photovoltaic grid-connected control method based on a wave notch filter and a proportional resonant controller, which is controlled based on a photovoltaic grid-connected control system. In order to ensure the waveform of the inverter output current and the quality of the output power, The voltage outer loop eliminates the DC side voltage U by adding a notch filter to the feedback DC voltage dc In order to further reduce the fluctuation of the DC bus voltage, the instantaneous current of the DC side is fed forward. For grid asymmetry faults (in the case of unbalanced grid voltage / asymmetric drop), the current inner loop model controls the negative sequence current component of the inverter to be zero, so as to effectively suppress the negative sequence component in the grid-connected current and ensure parallelism. The grid current has good power quality. In addition to the fundamental wave component, the grid-si...

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Abstract

The invention discloses a photovoltaic grid-connected control method and system based on a wave trap and a proportional resonance controller. The method comprises the steps of: establishing a maximumpower point tracking model, a positive and negative sequence separation model, a current control model and an inverter control model with harmonic suppression, wherein the maximum power point trackingmodel calculates the start or stop of maximum power point tracking according to an input voltage amplitude signal; enabling the positive-negative sequence separation model to calculate positive-negative sequence components of the power grid voltage; enabling the current control model to calculate a power grid active and reactive current reference value according to the power grid voltage amplitude;, wherein the inverter control model comprises a voltage outer loop control model with a wave trap and a current inner loop model adopting a proportional resonance controller added with harmonic suppression control, and calculates an inverter output voltage reference value according to the positive-negative sequence components of the power grid voltage and the power grid active and reactive current reference value. According to the invention, the interference of the harmonic component on the system under the asymmetric fault is solved, and the electric energy quality of the whole photovoltaic grid-connected system in the low-voltage ride through process is improved.

Description

technical field [0001] The invention belongs to the technical field of power systems, and in particular relates to a photovoltaic grid-connected control method and system based on a wave trap and a proportional resonance controller. Background technique [0002] At present, the problems of climate change and resource scarcity in the world are becoming increasingly prominent, and new energy sources such as solar energy are widely used for power generation. How to establish a photovoltaic grid-connected model with the same operating characteristics as the actual system, and study its low-voltage ride-through characteristics under fault conditions are of great significance for the study of safe and stable operation of the power grid. [0003] For a long time, many experts and scholars have conducted a lot of research work on the control strategy of inverters in photovoltaic grid-connected systems under fault conditions, and proposed a variety of strategies to improve the perfor...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02J3/16H02J3/01
CPCH02J3/01H02J3/16Y02E40/30Y02E40/40
Inventor 王力乔腾赵斌曾祥君王俊乐
Owner CHANGSHA UNIVERSITY OF SCIENCE AND TECHNOLOGY
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