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Composite droop control method and system suitable for DC micro-grid

A DC microgrid and control method technology, applied in the field of compound droop control method and system, can solve problems such as rising of given value, decrease of system operation stability, bus voltage fluctuation, etc., to maintain coordinated control and eliminate DC bus voltage deviation , Maintain the effect of stability and coordinated control

Active Publication Date: 2019-12-10
DONGGUAN UNIV OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But when the output current decreases, the given value of the DC bus voltage will rise, so the actual voltage value will also rise accordingly, so the bus voltage will fluctuate, and the stability of the system operation will decrease

Method used

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  • Composite droop control method and system suitable for DC micro-grid
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  • Composite droop control method and system suitable for DC micro-grid

Examples

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Embodiment 1

[0042] This embodiment provides a compound droop control method suitable for DC microgrids, such as figure 1 , including the following steps:

[0043] S1: Set the expected value of the DC bus voltage, that is, the expected value of the output DC voltage of the converter, and obtain the actual output current and output voltage of the converter;

[0044] S2: According to the expected value of the DC bus voltage and the actual output current of the converter, the given output voltage of the converter is obtained after calculation through the compound droop curve control, the target voltage U is controlled by the output current I and the output power P compound control, the control strategy adopts droop control;

[0045] S3: Perform voltage and current double closed-loop control of the converter to obtain a control signal of the converter.

[0046] The implementation of droop control of DC microgrid is as follows: figure 2 , the droop curve control is added to the voltage and ...

Embodiment 2

[0085] This embodiment provides a composite droop control system suitable for DC microgrids, such as Figure 9 ,include:

[0086] A DC unit, the DC unit is a power supply unit and an energy storage unit in a DC microgrid;

[0087] A converter, the DC unit is connected to the DC bus through the converter, and the control method described in Embodiment 1 is used in the converter to control the output voltage; the converter is a DC / DC converter.

[0088] A DC bus, the DC bus provides electric energy to loads.

[0089] The implementation method of the compound droop control of the DC microgrid is: add the droop curve control to the voltage and current double closed-loop control of the converter, as the control outer loop, obtain the reference value of the converter output DC voltage, and then perform the voltage and current double closed-loop control.

[0090] The same or similar reference numerals correspond to the same or similar components;

[0091] The terms describing the ...

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Abstract

The invention discloses a composite droop control method suitable for a DC micro-grid, comprising the following steps: S1, an expected value of the DC bus voltage (namely, an expected value of the DCvoltage output by a converter) is set, and an actual output current and an actual output voltage of the converter are acquired; S2, a given output voltage of the converter is obtained through composite droop curve control calculation according to the expected value of the DC bus voltage and the actual output current of the converter, wherein the composite droop curve control is that a target voltage U is subjected to composite control of an output current I and a output power P, and droop control is adopted as a control strategy; and S3, double closed-loop control is performed on the voltage and current of the converter to obtain a control signal of the converter. According to the invention, a voltage accurate control strategy based on the composite droop characteristic is adopted to ensure the voltage stability of an isolated DC micro-grid, and the influence of a local load is considered. Meanwhile, a DC bus voltage deviation-free control strategy based on voltage recovery is provided, in order to eliminate DC bus voltage deviation caused by the droop characteristic.

Description

technical field [0001] The present invention relates to the field of electrical engineering, and more specifically, to a composite droop control method and system suitable for DC microgrids. Background technique [0002] In DC microgrid, the fluctuation of DC bus voltage directly reflects the information of system power transmission. In the DC microgrid, it is defined that when each unit outputs power to the microgrid, the current is in the positive direction, that is, the current is positive when the unit is discharging, and the current is negative when charging. Traditional droop control includes single micro-source droop control and multi-micro-source (two or more) droop control: [0003] Single micro-source droop control: the expression of the droop characteristic curve is U ref =U 0 -KI, where K is the droop curve coefficient representing the slope, which can be equivalent to the series virtual impedance of each unit converter in the control. When the DC bus voltage...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J1/10H02J1/14
CPCH02J1/10H02J1/14
Inventor 张兆云喻礼礼刘艺涛张志陈树泉
Owner DONGGUAN UNIV OF TECH