Three-level Z source wind power generation grid-connected system

A wind power generator, three-level technology, applied in wind power generation, battery circuit devices, collectors, etc., can solve the problems of low utilization rate of wind energy, and achieve the effects of improving efficiency, strong anti-misconduction ability, and reducing volume

Inactive Publication Date: 2013-08-21
ANHUI UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to overcome the deficiencies in the prior art, improve the low utilization rate of wind energy of small and medium-sized vertical axis wind turbines, and provide a three-level Z-source wind power grid-connected system

Method used

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  • Three-level Z source wind power generation grid-connected system
  • Three-level Z source wind power generation grid-connected system
  • Three-level Z source wind power generation grid-connected system

Examples

Experimental program
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Effect test

specific Embodiment approach 1

[0026] Specific implementation mode 1: In this implementation mode, the wind speed is detected by the anemometer, and the bus voltage is detected by the DC bus voltage sampling unit. dcmin dc dcmax ), the power switch tube VT in the bidirectional DC / DC converter 1 , VT 2 Keep it off, the AC power generated by the wind turbine is rectified and used as the input of the Z-source inverter, and the voltage is boosted by the inverter, and the output power frequency AC is connected to the grid. The specific implementation process is as figure 2 As shown, the grid voltage sampling unit detects the grid voltage, uses the software phase-locked loop to obtain the synchronization information θ, and obtains d, q-axis voltage components after coordinate transformation, and obtains d, q after calculating with the given values ​​of active power and reactive power axis current given value; the grid-connected current sampling unit detects the grid-connected input current, and obtains the act...

specific Embodiment approach 2

[0028] Specific embodiment two: In this embodiment, the wind speed is detected by the anemometer, and the DC bus voltage sampling unit detects the bus voltage. When V dcmax dc And 11m / s1 Normal work, VT 2 constant cut-off, by an antiparallel diode D 4 A freewheeling channel is provided, and the bidirectional DC / DC converter works in step-down chopper mode. Part of the electric energy converted from wind energy is used for grid connection, and part of it is used for charging and storing the battery. VT 1 The pulse drive signal is generated by the PWM_DC / DC module in the FPGA, and is input to the VT through the isolated drive 2 module 1 . The Z-source inverter works in the grid-connected mode, and the specific process is shown in Embodiment 1. The charging voltage and charging current of a single lead-acid battery are as follows: Figure 6 shown.

specific Embodiment approach 3

[0029] Specific Embodiment Three: In this embodiment, the wind speed is detected by an anemometer. When the wind speed is in the range of 3 to 6 m / s, the power switch tube VT in the bidirectional DC / DC converter 1 Constant cut-off, VT 2 normal operation by the antiparallel diode D 3 A freewheeling channel is provided, and the bidirectional DC / DC converter works in boost chopper mode. At this time, after the bidirectional DC / DC step-up and chopping, the battery pack is used as the DC source of the Z-source inverter, and after step-up and inversion, it is connected to the grid and outputs power-frequency alternating current.

[0030] It should be noted that when the bidirectional DC / DC converter is working (especially in boost chopper mode), the DC bus voltage will be clamped by the battery chopper boost potential, which does not reflect the rectified AC power generated by the wind turbine. the actual voltage size. By measuring the wind speed, judge the actual wind energy sit...

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Abstract

The invention provides a three-level Z source wind power generation grid-connected system, and belongs to the field of wind power generation. The three-level Z source wind power generation grid-connected system comprises a duplex winding vertical axis wind power generator, an unloading protection unit, a first uncontrolled rectification unit, a second uncontrolled rectification unit, a Z source impedance network, a midpoint clamping three-level inverter, a grid-connected current sampling unit, a filter inductor L<f>, a grid-connected voltage sampling unit, a Z network voltage sampling unit, a direct current bus voltage detecting unit, a bidirection DC / DC conversion unit, a charging current detecting unit and a storage battery pack. According to the three-level Z source wind power generation grid-connected system, wind energy is converted into power frequency alternating current through the three-level Z source inverter, the power frequency alternating current is connected into a power grid, and working modes are changed over in real time on the condition of different wind speeds. When the wind energy is abundant, the system is connected to the power grid and also charges the storage battery pack, and the energy is stored; when the wind energy is moderate, the system only conducts grid-connected operation; when the wind speed is relatively low, the system is supplied with electricity by the storage battery pack to conduct the grid-connected operation, and therefore new energy wind power generation and use thereof are realized. The three-level Z source wind power generation grid-connected system is suitable for a small and medium size duplex winding vertical axis wind power generator unit.

Description

technical field [0001] The invention relates to the field of new energy power generation, in particular to a three-level Z-source wind power grid-connected system. Background technique [0002] my country is rich in wind energy resources, and wind power generation will be an important content in the utilization of new energy. The vertical axis wind power generation system has broad development prospects because of its advantages of accepting wind from any direction, simple structure, and easy installation and maintenance. At present, because large-scale vertical axis wind power generation systems have problems such as difficulty in starting at low wind speeds and low power generation efficiency at high wind speeds, small and medium-sized vertical axis wind power generation units are mostly used in grid-connected operation systems. The rectified DC bus voltage of small and medium-sized systems is relatively low, and the grid-connected inverter cannot be directly performed. O...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02J3/38H02J7/00
CPCH02M7/487Y02E10/76
Inventor 王静黄友锐董苏
Owner ANHUI UNIV OF SCI & TECH
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