Looking for breakthrough ideas for innovation challenges? Try Patsnap Eureka!

Self-adaptive quasi-PR active damping low-frequency harmonic suppression method

A harmonic suppression and adaptive technology, applied in harmonic reduction devices, AC networks to reduce harmonics/ripple, output power conversion devices, etc., can solve the problem of multi-inverter grid-connected systems. Resonance suppression and other issues to reduce hardware cost and power consumption, improve the quality of grid-connected current, and reduce THD

Pending Publication Date: 2022-08-05
HUNAN UNIV OF TECH
View PDF1 Cites 2 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, its patented method is only applicable to a single power grid system and cannot solve the problem of multi-point low-frequency resonance suppression in multi-inverter grid-connected systems.

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Self-adaptive quasi-PR active damping low-frequency harmonic suppression method
  • Self-adaptive quasi-PR active damping low-frequency harmonic suppression method
  • Self-adaptive quasi-PR active damping low-frequency harmonic suppression method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0080] like figure 1 As shown, this embodiment discloses an adaptive quasi-PR active damping low-frequency harmonic suppression method, which includes the following steps:

[0081] An adaptive quasi-PR active damping low-frequency harmonic suppression method, comprising the following steps:

[0082] S1: Use the inverter output impedance model to analyze the harmonic mechanism of the T-type three-level inverter system under double closed-loop control. Under the output impedance model, according to the parallel connection of n units working under the same conditions and with the same parameters The inverter is a whole, and the equivalent impedance model is established from the perspective of PCC as shown in Figure 3(b). The grid-connected current function of the LCL grid-connected inverter system under double closed-loop control is derived as:

[0083]

[0084] The sum of the current sources of the inverter, u g is the grid voltage. It can be seen from equation (1) that the...

Embodiment 2

[0142] In order to verify the correctness of the proposed control method, Matalab is used for simulation, and three T-type three-level grid-connected inverter models are built in MATLAB / Simulink simulation software. In this embodiment, the simulation parameters are shown in the following table:

[0143]

[0144]

[0145] PV side voltage and grid voltage u g are provided by a DC constant voltage source and an AC voltage source, respectively, where u g Contains 3rd, 5th and 7th harmonics; grid impedance Z g through the PCC point and u g Inductance in series between to simulate.

[0146] Figure 10(a) and (b) the reference current i during quasi-PR control and adaptive quasi-PR strategy, respectively ref and grid-connected current i g It can be seen from the figure that when quasi-PR control is used, the grid-connected current contains a large number of 3rd, 5th, and 7th harmonics, and the phase lags; On the other hand, the grid-connected current can also track the refe...

Embodiment 3

[0149] A photovoltaic grid-connected system adopts the adaptive quasi-PR active damping low-frequency harmonic suppression method in the previous embodiment 1, and on the basis of the conventional double closed-loop control, an adaptive quasi-PR control link is introduced, and on the basis of the quasi-PR control The phase compensation structure is introduced on the grid and the voltage proportional feedforward link is added at the PCC grid connection point, and the adaptive quasi-PR active damping low-frequency harmonic suppression method is obtained, which realizes the grid-connected current to the sinusoidal given current. And reduce the content of the 3rd, 5th, and 7th harmonics in the grid-connected current, increase the active damping of the system, and improve the system's ability to resist grid voltage disturbances. The equivalent conversion and cancellation of resonance can effectively suppress the self-resonance and parallel resonance of the LCL photovoltaic grid-conn...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The invention discloses a self-adaptive quasi-PR active damping low-frequency harmonic suppression method, and the method comprises the steps: introducing a self-adaptive quasi-PR control link on the basis of conventional double-closed-loop control, introducing a phase compensation structure on the basis of quasi-PR control, and adding a voltage proportion feedforward link at a PCC grid-connected point, thereby obtaining the self-adaptive quasi-PR active damping low-frequency harmonic suppression method. According to the method, zero-static-error tracking of grid-connected current to sine given current is achieved, the content of third, fifth and seventh harmonics in the grid-connected current is reduced, active damping of the system is increased, the capacity of the system for resisting power grid voltage disturbance is improved, meanwhile, main low-frequency resonance existing in an inverter in the grid-connected cluster system is equivalently converted and offset, and therefore the grid-connected cluster system is optimized. Self resonance and parallel resonance of the LCL photovoltaic grid-connected inverter are effectively inhibited; multi-point low-frequency resonance suppression of the multi-inverter grid-connected system is achieved, passive damping control can be replaced, the hardware cost and power consumption are effectively reduced, and the stability of the grid-connected system is remarkably improved.

Description

technical field [0001] The invention belongs to the technical field of electrical control, in particular to an adaptive quasi-PR active damping low-frequency harmonic suppression method. Background technique [0002] In a distributed generation system, the structure and control strategy of grid-connected inverters directly affect the power quality of the grid. As far as photovoltaic power generation systems are concerned, in practical situations, a large number of nonlinear devices are connected near the point of common coupling (PCC) of grid-connected inverters. On the basis of the traditional PR controller, many scholars have studied a phase compensation PR controller with an appropriate phase guiding angle embedded in the weak grid, that is, to ensure sufficient phase margin. , without peaking the magnitude response of the sensitivity transfer function. At present, the existing technicians take the traditional inverter as the research object, and propose an adaptive act...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
IPC IPC(8): H02J3/01H02J3/38H02M7/5387
CPCH02J3/01H02J3/381H02M7/53871H02J2203/20H02J2300/24Y02E40/40
Inventor 李圣清周水霜
Owner HUNAN UNIV OF TECH
Who we serve
  • R&D Engineer
  • R&D Manager
  • IP Professional
Why Patsnap Eureka
  • Industry Leading Data Capabilities
  • Powerful AI technology
  • Patent DNA Extraction
Social media
Patsnap Eureka Blog
Learn More
PatSnap group products

Browse by: Latest US Patents, China's latest patents, Technical Efficacy Thesaurus, Application Domain, Technology Topic, Popular Technical Reports.

© 2024 PatSnap. All rights reserved.Legal|Privacy policy|Modern Slavery Act Transparency Statement|Sitemap|About US| Contact US: help@patsnap.com