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A low-voltage microgrid multi-inverter parallel power sharing control method

A multi-inverter, micro-grid technology, applied in sustainable manufacturing/processing, single-grid parallel feeding arrangement, climate sustainability, etc., can solve harmonic power, inconsistent feeder impedance and inverter power sharing control , the implementation process is complex, the program calculation amount is large, etc.

Inactive Publication Date: 2017-02-08
STATE GRID CORP OF CHINA +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, this patent needs to perform fast Fourier transform FFT on the instantaneous active power and instantaneous reactive power, frequency division to detect the characteristic sub-harmonic power, and then calculate and synthesize the harmonic reference voltage for the characteristic sub-harmonic respectively, so that the specific implementation The process is too complicated, and the calculation amount of the program is relatively large, which may affect the fast response speed of the system
[0010] To sum up, the prior art has not solved the problem of inverter power sharing control in low-voltage microgrids due to actual complex factors such as harmonic power, inconsistency of feeder impedance, and inconsistency of inverter rated capacity. technical challenge

Method used

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  • A low-voltage microgrid multi-inverter parallel power sharing control method
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  • A low-voltage microgrid multi-inverter parallel power sharing control method

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Experimental program
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Effect test

Embodiment 1

[0080] A low-voltage micro-grid multi-inverter parallel power sharing control method, the method is applicable to a low-voltage micro-grid multi-inverter parallel power sharing control system, the low-voltage micro-grid multi-inverter parallel power sharing The control system includes several parallel inverters, common bus, linear and nonlinear loads, and centralized controller; the main circuit of the inverter includes sequentially connected DC stabilized power supplies, H-bridge inverter circuits, and LC filter circuits , feeder, the H-bridge inverter circuit is provided with S 1 -S 4 Four power switching tubes, the inverter also includes drive and protection circuits, and a local controller; several parallel inverters are connected to a common bus through the feeder, and linear and nonlinear loads are connected to the common bus , a centralized controller is also arranged on the common bus;

[0081] The centralized controller samples, processes and calculates the common b...

Embodiment 2

[0100]According to a low-voltage microgrid multi-inverter parallel power sharing control method described in Embodiment 1, it is further defined as, in the step (1), the centralized controller controls the common bus voltage u pcc Carry out sampling, processing and calculation to obtain the d coordinate component u of the h order harmonic component of the common bus voltage in the dq coordinate system pcch_d and the q coordinate component u of the h order harmonic component of the common bus voltage in the dq coordinate system pcch_q , the specific steps include:

[0101] a. The centralized controller adopts the sliding window discrete Fourier transform SDFT to extract the common bus voltage u pcc The fundamental component u pccf_α and common bus voltage u pcc The hth harmonic component u pcch_α , for the common bus voltage u pcc The fundamental component u pccf_α Delay a quarter of the power frequency cycle to get the common bus voltage u pcc The fundamental component ...

Embodiment 3

[0111] According to a low-voltage microgrid multi-inverter parallel power sharing control method described in Embodiment 1, it is further defined as, in the step (3), the instantaneous active power p is obtained by digital low-pass filtering to obtain the active power of the inverter The average value of power P and the virtual instantaneous reactive power q are obtained by digital bandpass filtering to obtain the average value of reactive power Q of the inverter. The calculation formula is shown in formula (Ⅳ):

[0112] P = ω o s + ω o p Q = ω o s...

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Abstract

The invention provides a method for averagely controlling parallel power of inverters of a low-voltage micro-grid. A method of multiplying feeder line current and virtual complex impedances to obtain base wave virtual impedance voltage is used, output impedances of the inverters are designed to be ohmic and are matched with features of electrical parameters of a feeder line of the low-voltage micro-grid, and droop control output reference voltage is calculated and synthesized by a method of controlling power droop under the condition of ohmic equivalent output impedances; and a phase angle of the droop control output reference voltage is extracted and replaces a phase angle of common busbar voltage to perform dq / alpha beta coordinate transformation, and delay and distortion which are caused by the reason that the phase angle of the common busbar voltage is transmitted to a local controller from an integrated controller through low-bandwidth communication are avoided. When the method is used for a system for averagely controlling the parallel power of the inverters of the low-voltage micro-grid under the conditions that a nonlinear load exists, the feeder line impedances of the inverters are different, and the rated capacities of the inverters are different and the like, average control on the output power of the inverters can be realized, and circulation of the inverters can be restrained effectively.

Description

technical field [0001] The invention relates to a low-voltage micro-grid multi-inverter parallel power sharing control method, which belongs to the technical field of distributed power generation and smart grid. Background technique [0002] In order to solve the technical problems of connecting distributed power sources to the power grid, scholars related to power systems have proposed the concept of micro-grids. A microgrid is a local power generation system that is composed of distributed micro sources, energy conversion devices, and local loads interconnected through a network, and can realize self-control, protection, and management. In the microgrid, most distributed micro-sources are connected to the AC bus through the inverter interface, thus forming a multi-inverter parallel operation environment. [0003] Due to the variety of local loads on the AC bus, there are inevitably nonlinear loads, which brings great challenges to the inverter control in the microgrid: in...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/46
CPCY02P80/14
Inventor 杨慕华张庆海周海全李洪博刘安华
Owner STATE GRID CORP OF CHINA
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