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A new voltage-type control method for photovoltaic grid-connected inverters

A control method and inverter technology, applied in photovoltaic power generation, conversion of irreversible DC power input to AC power output, single-network parallel feeding arrangement, etc. Voltage stability and other issues to achieve the effect of enhancing control capabilities

Inactive Publication Date: 2016-04-06
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] In order to solve the problem that the grid-connected power of the existing voltage-controlled inverter is easily affected by grid fluctuations and cannot stabilize the DC bus voltage, the invention provides a new voltage-type control method for photovoltaic grid-connected inverters

Method used

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  • A new voltage-type control method for photovoltaic grid-connected inverters
  • A new voltage-type control method for photovoltaic grid-connected inverters
  • A new voltage-type control method for photovoltaic grid-connected inverters

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specific Embodiment approach 1

[0031] Specific implementation mode one: see figure 1 and 2 Describe this embodiment, the novel photovoltaic grid-connected inverter voltage type control method described in this embodiment,

[0032] Step 1: Introduce the closed-loop feedback control method into the droop control, increase the power loop, and obtain the droop curve U after Laplace transform 0 The translation amount △ U 0 and inverter rated output frequency f 0 The translation amount △f 0 ,

[0033] Step 2: Put the sagging curve U 0 The translation amount △ U 0 and inverter rated output frequency f 0 The translation amount △f 0 Superimposed on the grid-connected droop equation of the voltage type of the new photovoltaic grid-connected inverter, and simplified to obtain the equation,

[0034] U = U 0 + ( k pp + k ip ...

specific Embodiment approach 2

[0048] Specific implementation mode two: see figure 1 and 2 Describe this embodiment. The difference between this embodiment and the voltage-type control method of the new photovoltaic grid-connected inverter described in the first specific embodiment is that the voltage-type grid-connected droop equation of the new photovoltaic grid-connected inverter is:

[0049] U=U 0 -k p (P-P 0 )(1),

[0050] f=f 0 +k q (Q-Q 0 )(2),

[0051] Among them, k p is the droop coefficient of the output active power of the inverter, k q is the droop coefficient of the inverter output reactive power, Q 0 is the rated reactive power output by the inverter, P 0 is the rated active power output by the inverter.

specific Embodiment approach 3

[0052] Specific implementation mode three: see figure 1 and 2 This embodiment is described. The difference between this embodiment and the voltage-type control method of the new photovoltaic grid-connected inverter described in the first specific embodiment is that:

[0053] The drooping curve U 0 The translation amount △ U 0 and inverter rated output frequency f 0 The translation amount △f 0 middle,

[0054] Δ U 0 = ( k pp + k ip s ) ( P PV - P ) - - - ( 3 ) ,

[0055] Δf 0 = ( ...

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Abstract

The invention provides a voltage type control method for a novel photovoltaic grid-connected inverter and relates to a voltage type control method for the grid-connected inverter. The method aims to solve the problems that grid-connected power of the voltage control type inverter is prone to being influenced by power grid fluctuation, and direct-current bus voltage can not be stabilized. The method comprises the following steps that 1, a closed-loop feedback control method is introduced into droop control, power rings are increased, and a translation quantity delta U0 of a droop curve U0 and a translation quantity delta f0 of rated output frequency f0 of the inverter are obtained after laplace transformation of the power rings is carried out; 2, the translation quantity delta U0 of the droop curve U0 and the translation quantity delta f0 of the rated output frequency f0 of the inverter are respectively superposed to a grid-connected droop equation of the voltage type of the novel photovoltaic grid-connected inverter, the grid-connected droop equation is simplified to obtain an equation, the power rings in the equation obtained after simplification are replaced by direct-current bus voltage rings, and the novel photovoltaic grid-connected inverter can control the direct-current bus voltage. The method is mainly applied to the grid-connected inverter.

Description

technical field [0001] The invention relates to a voltage type control method of a grid-connected inverter. Background technique [0002] The grid-connected active power is regulated by the inverter output voltage amplitude, and the grid-connected reactive power is regulated by the inverter phase. Therefore, the output power equation when the voltage-controlled inverter is connected to the grid is similar to the parallel droop control of the inverter . Traditional droop control ignores the resistive component in the line impedance, and considers the transmission line to be mainly inductive. The low-voltage power transmission line is mainly resistive, so the voltage-type grid-connected droop equation of the inverter can be obtained [0003] U=U 0 -k p (P-P 0 )(1) [0004] f=f 0 +k q (Q-Q 0 )(2) [0005] In the formula, U is the reference value of inverter output voltage amplitude, f is the reference value of inverter output frequency, f 0 is the rated output freque...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/38H02M7/48
CPCY02E10/56
Inventor 王卫刘鸿鹏刘桂花王盼宝佟云剑徐殿国
Owner HARBIN INST OF TECH
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