Control method and control system for photovoltaic grid-connected inverter

A control method and control system technology, applied in the field of photovoltaic grid-connected inverter control method and its control system, can solve problems such as sudden changes in inverter input voltage and bus voltage, easily damaged inverter equipment, etc., and achieve adjustment The effect of high efficiency and fast response time

Active Publication Date: 2011-04-06
EMERSON NETWORK POWER CO LTD
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  • Abstract
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  • Claims
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Problems solved by technology

[0003] Due to the characteristics of the solar power generation system, the input voltage of the inverter and the output bus voltage need to be controlled within a certain threshold range, and when the low-voltage ride-through function is performed, the drop of the grid voltage will cause the input voltage of the inverter and the bus voltage to drop. mutation, it is easy to damage the inverter equipment, but in the prior art, there is a lack of protection for photovoltaic grid-connected power generation equipment when the voltage suddenly changes

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  • Control method and control system for photovoltaic grid-connected inverter
  • Control method and control system for photovoltaic grid-connected inverter
  • Control method and control system for photovoltaic grid-connected inverter

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Embodiment Construction

[0022] The photovoltaic grid-connected power generation control system of the present invention includes a control unit, which includes a detection module and a control module; wherein, the detection module also includes a mains monitoring module, and the control module includes: a DC / DC control module, an MPPT module, and a low-voltage ride-through control module. modules and island protection control modules (such as figure 1 shown).

[0023] figure 2 , image 3 Shown is a schematic diagram of the control flow of this embodiment, first combined with image 3 The overall control flow of this embodiment is described, and its control flow includes the following steps:

[0024] 1) Monitor the operating state of the mains network through the mains monitoring module, which includes but not limited to undervoltage, overvoltage and abnormal frequency; and send the monitoring data to the control module;

[0025] 2) When the overvoltage or abnormal frequency of the mains network ...

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Abstract

The invention relates to a control method and a control system for a photovoltaic grid-connected inverter. The control method comprises the following steps of: A1, detecting an input voltage value of the currently working direct current / direct current (DC / DC) system of the inverter in real time; A2, calculating a duty cycle upper limit value of the working DC / DC system of the inverter according to the input voltage value and a preset bus voltage limit value; and A3, comparing the current output voltage of the DC / DC system of the inverter with the bus voltage limit value, and controlling the DC / DC system of the inverter to work at the duty cycle upper limit value when the current output voltage of the DC / DC system of the inverter is greater than the bus voltage limit value. The system is used for implementing the method. The method and the system have the advantages that: by controlling duty cycle, the output voltage of the photovoltaic grid-connected inverter can be controlled in a predetermined range when a mains supply network is undervoltage, and the inverter and other equipment are effectively prevented from being damaged.

Description

technical field [0001] The invention relates to the field of photovoltaic grid-connected power generation, in particular to a control method and a control system for a photovoltaic grid-connected inverter. Background technique [0002] The smart grid puts forward higher requirements for grid-connected power generation equipment. In addition to stable, safe and reliable work, it also needs to be tolerant to grid abnormalities. In some cases, grid-connected equipment is required to hope for large-scale power generation when the grid fails. Substations can share the pressure of part of the grid, rather than off-grid (intensifying the impact on the grid), so in large-scale power generation equipment, the equipment is required to have the function of low-voltage ride-through, but at the same time, it must also prevent the island effect. [0003] Due to the characteristics of the solar power generation system, the input voltage of the inverter and the output bus voltage need to be...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02H7/10
CPCY02E10/563Y02E10/56
Inventor 杨文辉
Owner EMERSON NETWORK POWER CO LTD
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