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Fault riding-through method and device and photovoltaic power generation system

A photovoltaic power generation system and fault ride-through technology, applied in photovoltaic power generation, circuit devices, electrical components, etc., can solve the problems of reducing the injected power of DC-DC converters and slow response speed of DC bus voltage control, so as to reduce fluctuations, Realize the effect of fault ride-through

Pending Publication Date: 2018-09-21
ELECTRIC POWER RESEARCH INSTITUTE, CHINA SOUTHERN POWER GRID CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

When the AC power grid fails, if the DC-AC converter detects the fault and transmits this signal to the DC boost controller through communication, the injected power of the DC-DC converter can be reduced, thereby reducing the DC bus voltage, but the DC boost There is a certain delay in the communication between the voltage controller and the power-current dual-loop controller, and the control response speed of the DC bus voltage is relatively slow

Method used

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  • Fault riding-through method and device and photovoltaic power generation system
  • Fault riding-through method and device and photovoltaic power generation system
  • Fault riding-through method and device and photovoltaic power generation system

Examples

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Embodiment 1

[0044] see figure 1 , figure 1 It is a flow chart of a fault ride-through method provided by an embodiment of the present invention; including:

[0045] S1. Obtain the voltage deviation and current measurement value of the photovoltaic panel, and convert the voltage deviation into a current inner loop reference value;

[0046] S2. Acquiring the voltage deviation of the DC bus, and judging whether the voltage deviation of the DC bus is greater than a dead zone threshold;

[0047] S3. If yes, then output the deviation between the voltage deviation of the DC bus and the dead zone threshold, and multiply the deviation by a proportional coefficient to obtain the current deviation; if not, output the deviation is zero;

[0048] S4. Calculate the value of the current inner loop reference value minus the current measurement value of the photovoltaic panel and the current deviation to obtain the current reference value of the photovoltaic panel;

[0049] S5. Convert the current ref...

Embodiment 2

[0057] see image 3 , image 3 It is a schematic structural diagram of a fault ride-through device provided by an embodiment of the present invention; it includes:

[0058] The first voltage outer loop control module 1 is used to obtain the voltage deviation of the photovoltaic panel, and convert the voltage deviation into a current inner loop reference value;

[0059] The second voltage outer loop control module 2 is used to obtain the voltage deviation of the DC bus, and judge whether the voltage deviation of the DC bus is greater than the dead zone threshold; if so, then output the voltage deviation of the DC bus and the The deviation value of the dead zone threshold value, and multiply the deviation value by the proportional coefficient to obtain the current deviation amount; if not, then output the deviation value as zero;

[0060] The current inner loop control module 3 is used to obtain the current measurement value of the photovoltaic panel, and is also used to calcu...

Embodiment 3

[0072] see Figure 4 , Figure 4 It is a structural schematic diagram of a photovoltaic power generation system provided by an embodiment of the present invention; including:

[0073] Photovoltaic panel 101, DC boost converter 102, DC-AC converter 103, DC-AC controller 107, transformer 104, AC power grid 105, and the fault ride-through device 106 described in the second embodiment; wherein,

[0074] The photovoltaic panel 101 is used to convert light energy into a DC voltage, and transfer the DC voltage into a DC bus, and the DC bus is used to connect the photovoltaic panel 101 and the DC boost converter 102; The DC boost converter 102 is used to boost the DC voltage; the DC-AC converter 103 is used to convert the boosted DC voltage into an AC voltage; the transformer 104 is used to convert the DC voltage to the AC voltage. The voltage is boosted, so that the boosted AC voltage is input into the AC grid 105; the DC-AC controller 107 is used to control the operation of the DC...

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Abstract

The invention discloses a fault riding-through method applicable to a photovoltaic power generation system. The fault riding-through method comprises the following steps: acquiring a voltage deviationamount and a measured current value of a photovoltaic panel, and converting the voltage deviation amount into a current inner loop reference value; judging whether a voltage deviation amount of a direct current busbar is greater than a dead zone threshold value; if the voltage deviation amount of the direct current busbar is greater than the dead zone threshold value, outputting a deviation valuebetween the voltage deviation amount of the direct current busbar and the dead zone threshold value, and multiplying the deviation value by a proportional coefficient to obtain a current deviation amount; calculating a value obtained by subtracting the measured current value of the photovoltaic panel and the current deviation amount from the current inner loop reference value to obtain a currentreference value of the photovoltaic panel; converting the current reference value into a duty cycle signal so as to enable the photovoltaic power generation system to control the stability of the voltage of the direct current busbar according to the duty cycle signal. The invention further discloses a fault riding-through device and the photovoltaic power generation system. Under the premise of nocommunication, effective limitation of the injection power of the photovoltaic panel during an alternating current grid failure can be achieved, fluctuation of the voltage of the direct current busbar is reduced, and ultimately the fault ride-through of the photovoltaic power generation system is achieved.

Description

technical field [0001] The invention relates to the technical field of photovoltaic power generation, in particular to a fault ride-through method, device and photovoltaic power generation system. Background technique [0002] At present, with the rapid decline in the cost of development and application of renewable energy. The installed capacity of power generation systems such as wind power and photovoltaics continues to increase. In 2015, the newly installed capacity of global renewable energy power generation exceeded the installed capacity of conventional energy power generation for the first time, indicating that the construction of the global power system is undergoing structural changes. [0003] In the photovoltaic power generation process of the prior art, the electric energy generated by the photovoltaic power generation system is first boosted by a DC-DC (direct current-direct current) converter, collected and merged into the DC bus, and then passed through a DC...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02J1/02
CPCH02J3/385H02J1/02Y02E10/56
Inventor 张野洪潮张帆杨健李俊杰孙鹏伟
Owner ELECTRIC POWER RESEARCH INSTITUTE, CHINA SOUTHERN POWER GRID CO LTD
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