Composite virtual harmonic impedance control method for grid-connected inverter

A technology of virtual harmonic impedance and control method, applied in AC network to reduce harmonics/ripple, harmonic reduction device, single-grid parallel feeding arrangement, etc., can solve the instability of grid-connected inverter control system, etc. question

Active Publication Date: 2015-11-04
HEFEI UNIV OF TECH
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Problems solved by technology

Simulation and experiments prove that the resistance-type virtual harmonic impedance control method needs to virtualize a smaller harmonic resistance in order to achieve better distortion suppression effect, but the smaller harmonic resi

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  • Composite virtual harmonic impedance control method for grid-connected inverter
  • Composite virtual harmonic impedance control method for grid-connected inverter
  • Composite virtual harmonic impedance control method for grid-connected inverter

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Embodiment Construction

[0041] The specific implementation manners of the present invention will be described below in conjunction with the accompanying drawings.

[0042] Such as figure 1 As shown in the structural diagram of the present invention, the proposed grid-connected inverter composite virtual harmonic impedance control method, by controlling the grid-connected inverter in the harmonic frequency band, virtualizes a resistance branch and a parallel connection of the resistance and inductance branch branch, to suppress the harmonic source I h or grid background harmonics V g The resulting grid-connected point voltage V PCC distortion. Compared with the traditional grid-connected inverter resistive virtual harmonic impedance control method, the proposed invention has stronger system stability and better ability to suppress voltage harmonics at the grid-connected point.

[0043] figure 2 It is a control structure diagram of the present invention. In this embodiment, the LCL filter parame...

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Abstract

The invention provides a composite virtual harmonic impedance control method for a grid-connected inverter. The method mainly comprises the steps of: sampling the voltage of a grid-connected point of the inverter and calculating an active component V<PCCd> and a reactive component V<PCCq>; using a high-pass filter to extract V<PCCd_h> and V<PCCq_h>, and calculating order current harmonic parts i*<d_h> and i*<q_h>; calculating a direct current voltage error [delta]U<dc> and calculating an order current fundamental wave part active component i*<d_f>; and setting an order current fundamental wave part reactive component i*<q_f> as zero; and calculating inverter output voltages u, u and u<c>, and controlling the breakthrough and cutoff of a switch tube in a three-phase full-bridge inverter circuit via PWM. The composite virtual harmonic impedance control method of the invention is to simulate parallel branches of a resistance branch and a resistance-inductance branch at a harmonic wave frequency band by controlling the grid-connected inverter so as to suppress the distortion of grid-connected voltage VPPC caused by a harmonic source I<h> or power grid background harmonic wavea V<g>. Compared with a traditional resistor type virtual harmonic impedance control method for the grid-connected inverter, the composite virtual harmonic impedance control method has stronger system stability and better grid-connected voltage harmonic suppression capacity.

Description

technical field [0001] The invention relates to a compound virtual harmonic impedance control method of a grid-connected inverter, which belongs to the technical field of distributed grid-connected power generation. Background technique [0002] With the development of the country's industry and the improvement of people's living standards, various electrical loads with different characteristics are connected to the power grid, causing the voltage of the power grid to be distorted. The distortion of the grid voltage not only brings serious harm to the safe and reliable power supply of the power system, but also may damage the electrical equipment, which has a negative impact on human safety and economic benefits. [0003] Aiming at this problem, a common practice at present is to use an LC tuned filter or an active power filter (Active Power filter, APF) to compensate the grid harmonics. The compensation effect of the LC tuned filter is easily affected by the parameters of ...

Claims

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Application Information

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IPC IPC(8): H02J3/38H02J3/01
CPCY02E40/40
Inventor 李飞张兴李浩源朱虹马铭遥刘芳
Owner HEFEI UNIV OF TECH
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