Single-phase inverter parallel control method based on virtual complex impedance

A virtual complex impedance, single-phase inverter technology, applied in the direction of output power conversion device, AC power input conversion to DC power output, electrical components, etc., can solve the problem of aggravating the voltage drop of the busbar and increasing the equivalent output impedance of the system and other issues to achieve the effect of reducing power coupling and reducing the impact

Inactive Publication Date: 2016-10-12
JIANGSU UNIV
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  • Abstract
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Problems solved by technology

In addition, most of the existing virtual impedance methods increase the equivalent output impedance of the system to varying degrees and aggravate the bus voltage drop.

Method used

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  • Single-phase inverter parallel control method based on virtual complex impedance
  • Single-phase inverter parallel control method based on virtual complex impedance
  • Single-phase inverter parallel control method based on virtual complex impedance

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Embodiment Construction

[0029] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

[0030] The equivalent circuit diagram of two inverters running in parallel in the microgrid is as follows: figure 1 shown. Among them, the sum of the output impedance of each inverter and the connection impedance is Z n ∠θ n (n=1,2), the output voltage of each inverter is The output currents are I on (n=1,2), the circulation between the two inverters is I H , the common load terminal voltage is U o ∠0, the load terminal current is I o .

[0031] The power injected by the inverter into the AC bus can be expressed as

[0032]

[0033]

[0034] Since the sum of the output impedance and the wiring impedance is purely resistive,

[0035]

[0036]

[0037] Differentiate the above two equations respectively to get the differential form:

[0038]

[0039] Due to the magnitude of the value, the phase difference to be much sma...

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Abstract

The invention proposes a single-phase inverter parallel control method based on virtual complex impedance, and the virtual complex impedance consists of virtual negative inductance and virtual positive resistance. The high frequency burr in the output of an inverter is filtered through an LC filter, and the output of the inverter is connected to an output AC bus through a line. Because of the existing of the filter inductance, the output impedance of the inverter is inductive, but not purely inductive. After the virtual complex impedance is added, the method can counteract the inductiveness generated by the filter inductance, thereby enabling the equivalent output impedance of the inverter to be resistive. The control method is suitable for a multi-inverter parallel control system in a low-voltage microgrid.

Description

technical field [0001] The invention belongs to power electronic control technology, in particular to a multi-inverter parallel control method when a low-voltage microgrid operates in an isolated island. Background technique [0002] With its effective use of distributed power and its flexible and intelligent control characteristics, microgrid has become one of the key points of power development strategies in many countries in the next few years. Since most distributed power sources in the microgrid need to be integrated into the microgrid through inverters, the stable parallel operation of the inverters will greatly improve the overall capacity and reliability of the microgrid system. [0003] At present, the parallel operation control strategy of inverters generally adopts master-slave control method and droop control method. The master-slave control method requires interconnection wires in control, which will limit the distance between parallel distributed power supplie...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/5387
CPCH02M7/53873H02M7/53876
Inventor 刘国海姜宇珺陈兆岭姜宇琦
Owner JIANGSU UNIV
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