A grid-connected robust control method for AC/DC hybrid microgrid considering uncertainty

An AC-DC hybrid and uncertain technology, applied in the field of robust control of AC-DC hybrid micro-grid, can solve the problem of inaccurate model establishment and exacerbate the difficulty of AC-DC hybrid micro-grid grid connection, AC-DC hybrid micro-grid model Uncertainty and other issues to achieve the effect of improving robust performance

Active Publication Date: 2021-01-08
NORTH CHINA ELECTRIC POWER UNIV (BAODING) +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Factors such as distributed power sources contained in the AC-DC hybrid microgrid, aging components in the inverter, and inaccurate model establishment make the model of the AC-DC hybrid microgrid uncertain, which intensifies the risk of grid-connected AC-DC hybrid microgrids. difficulty

Method used

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  • A grid-connected robust control method for AC/DC hybrid microgrid considering uncertainty
  • A grid-connected robust control method for AC/DC hybrid microgrid considering uncertainty
  • A grid-connected robust control method for AC/DC hybrid microgrid considering uncertainty

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0165] Example 1: The grid-connected point voltage is a standard industrial frequency sinusoidal voltage, the AC-DC hybrid microgrid runs off-grid, and is merged into the large power grid at 0.3s.

[0166] Depend on Figure 7 and Figure 8 It can be seen that after 0.3s grid connection, using H ∞ Both robust control and PI control can realize AC-DC hybrid microgrid system grid connection without oscillation instability. Depend on Figure 9 It can be seen that using H ∞ The robust control system has no inrush current and can reach a steady state within two power frequency cycles; while the PI control system has a certain inrush current and needs to go through six power frequency cycles to reach a steady state. i.e. using H ∞ Robust control without grid-connected impact current, which can realize AC-DC hybrid micro-grid grid-connected control more quickly and accurately.

Embodiment 2

[0167] Example 2: The grid-connected point voltage is a standard industrial frequency sinusoidal voltage, and the AC-DC hybrid microgrid adopts H ∞ Robust control, when the off-grid operation reaches 0.3s, the AC load suddenly increases by 80kW.

[0168] Depend on Figure 10 It can be seen that when the AC load has a step disturbance, H ∞ Robust control can maintain the stability of the AC bus current, and make the A-flow bus current have an excellent dynamic response, no inrush current, and the dynamic adjustment time is short enough.

Embodiment 3

[0169] Example 3: The grid-connected point voltage is a standard power frequency sinusoidal voltage. The AC-DC hybrid microgrid runs in the grid-connected state and is off-grid at 0.9s. H designed for verification ∞ The performance of the robust controller is to perturb the system filter parameters shown in Table 1 by 30%, that is, R e = 0.14Ω, R s = 0.07Ω, L e =1.05mH,L s =0.42mH, C=1050uF.

[0170] Depend on Figure 11 and Figure 13 It can be seen that before the system component parameters are perturbed, the PI control and the H ∞ The total harmonic distortion (THD) of the system under robust control is 0.50% and 0.41%, respectively, which can basically achieve error-free tracking and the control effect is good. Depend on Figure 12 and Figure 14 It can be seen that considering the model uncertainty, after the perturbation of system component parameters, the performance of the system using PI control deteriorates, and the THD increases significantly to 10.70%, w...

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Abstract

Provided is an AC / DC hybrid micro-grid grid connection robust control method taking uncertainty into consideration. The method includes the following steps: on the basis of the superposition theorem,establishing an AC / DC hybrid micro-grid grid connection mathematical model and a feed-forward system mathematical model in accordance with an AC / DC hybrid micro-grid grid connection topological structure; independently controlling a DC sub-micro-grid and providing a reference voltage to a filter capacitor in an AC / DC hybrid micro-grid; and constructing an AC / DC hybrid micro-grid grid connection robust controller and AC / DC hybrid micro-grid grid connection is achieved, so the robust performance of the AC / DC hybrid micro-grid is improved. The method of the invention avoids overcurrents in grid connection points during AC / DC hybrid micro-grid grid connection, realizes seamless switching, and enables AC / DC hybrid microgrids still to be normally connected in a condition of certain parameter perturbation.

Description

technical field [0001] The invention relates to a grid-connected robust control method of an AC-DC hybrid micro-grid. In particular, it involves a robust control method for AC-DC hybrid microgrid grid-connected considering uncertainty. Background technique [0002] The microgrid provides an effective way for high-density distributed energy to connect to the distribution network. The AC-DC hybrid micro-grid can comprehensively utilize the respective advantages of the AC micro-grid and the DC micro-grid, reduce the power conversion link, and make the distributed power supply more flexible, reliable, and economical grid-connected operation, thereby improving power supply reliability and power quality. [0003] The AC-DC hybrid microgrid can be divided into three parts: the AC sub-microgrid, the DC sub-microgrid, and the AC-DC power control area. With the new control form of "partition autonomy and regional coordination", the AC-DC hybrid microgrid is guaranteed to operate effi...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/38
CPCH02J3/38H02J2203/20
Inventor 李鹏郭天宇陈安伟张亮
Owner NORTH CHINA ELECTRIC POWER UNIV (BAODING)
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