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Parallel power sharing control method for microgrid inverters based on virtual capacitor

A technology of virtual capacitors and inverters, which is applied in the field of power sharing control of microgrid inverters based on virtual capacitor algorithms, and can solve the problems of equalizing load power of inverters.

Active Publication Date: 2017-12-01
黄山科创中心有限责任公司
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] The purpose of the present invention is to solve the problem that each inverter cannot share the load power according to its rated capacity when the micro-grid inverters are running in parallel in an isolated island, and to provide a parallel-connected and equal-sharing control method for micro-grid inverters based on virtual capacitors, without the need for inverters. Interconnection communication between inverters and line impedance detection can adaptively compensate line impedance voltage drop and improve the reactive power sharing ability and output voltage accuracy of each inverter

Method used

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  • Parallel power sharing control method for microgrid inverters based on virtual capacitor
  • Parallel power sharing control method for microgrid inverters based on virtual capacitor
  • Parallel power sharing control method for microgrid inverters based on virtual capacitor

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Embodiment Construction

[0070] The embodiment will be described in detail below with reference to the drawings.

[0071] figure 1 It is a parallel system of two microgrid inverters of the same capacity, the inverter number is #i=1, 2. The inverter #i DC voltage is 600V, the rated output line voltage is 380V / 50Hz, the filter inductance value is 0.5mH, the filter capacitor value is 200uF, and the inverter rated capacity is 100KVar. Inverter #1 wire impedance is Z L1 =0.001+j0.004Ω, the connection impedance of inverter #2 is Z L2 =0.075+j0.025Ω.

[0072] figure 2 It is a block diagram of the inverter control structure according to an embodiment of the present invention. The steps of the control method of the present invention are as follows:

[0073] Step 1: Let the number of microgrid inverters be n, and n≥2, #i represents the inverter number, and i∈[2,n].

[0074] In this embodiment, n=2, and inverter numbers #i are #1 and #2 respectively.

[0075] Step 2: Sampling 2 sets of microgrid inverter #i output ph...

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Abstract

The invention discloses a parallel power sharing control method for micro-grid inverters based on virtual capacitance. The method first uses the power outer loop of the power outer loop control algorithm to obtain the voltage amplitude and phase angle value, and then adds the virtual capacitance algorithm to obtain the output Voltage amplitude and phase angle commands, and double closed-loop control of output voltage, capacitance and current. The virtual capacitor algorithm simulates the characteristics of parallel capacitors at the output of the inverter through the control algorithm, and adjusts the output voltage and reactive power of the inverter. The virtual capacitor value is calculated according to the output reactive power of each inverter and the capacitance droop formula. The invention does not require interconnection communication between inverters and line impedance detection, can self-adaptively compensate line impedance voltage drop, and improve the reactive power sharing ability and output voltage accuracy of each inverter.

Description

Technical field [0001] The invention belongs to the power sharing control field of parallel islanding operation of microgrid inverters, and in particular relates to a power sharing control method for microgrid inverters based on a virtual capacitor algorithm. Background technique [0002] With the increasingly serious environmental and energy problems and the development and wide application of distributed power generation technologies such as photovoltaics and wind power, microgrid systems have become a research focus. In order to improve system reliability and redundancy, and reduce dependence on communication, voltage source inverter networking with droop control or virtual synchronous motor control is often used to achieve effective load power distribution. [0003] Since there are inductive components such as filter inductors and isolation transformers in the inverter circuit structure, its output impedance and line impedance are mainly inductive. Therefore, the ratio of the a...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/46
Inventor 张兴徐海珍刘芳石容亮毛福斌
Owner 黄山科创中心有限责任公司
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