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Disturbance voltage generating device for measuring impedance characteristic of grid-connected equipment port

A technology of perturbing voltage and generating device, which is applied in the direction of measuring device, measuring electrical variable, output power conversion device, etc., can solve problems such as affecting the output voltage accuracy, setting chopper unit, high-frequency pulsation, etc.

Pending Publication Date: 2022-08-02
SHENZHEN HOPEWIND ELECTRIC CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Because the DC link of this patent requires multi-channel isolation, the input uses multi-winding transformers and multi-channel rectifiers, the system is complex; and because its power unit is three-phase isolated, when it outputs power, there will be high-frequency pulsations on the DC voltage, affecting Output Voltage Accuracy
[0006]The above two patents realize multi-channel isolated DC power supply through multi-winding input transformer and multiple rectifiers, and realize direct stage of output terminal through corresponding multi-channel inverter In addition, it is difficult to set up a chopper unit on a multi-channel DC power supply for discharging in the event of an inverter failure

Method used

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  • Disturbance voltage generating device for measuring impedance characteristic of grid-connected equipment port
  • Disturbance voltage generating device for measuring impedance characteristic of grid-connected equipment port
  • Disturbance voltage generating device for measuring impedance characteristic of grid-connected equipment port

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Embodiment 1

[0043] see image 3 , image 3 It is a system structure diagram of the first embodiment of the disturbance voltage generating device that can be used for the measurement of the impedance characteristics of the ports of the grid-connected equipment;

[0044] The present embodiment discloses a disturbance voltage generating device for measuring the port impedance characteristic of grid-connected equipment, including a rectifier unit, an inverter unit, an isolation unit, an output filter unit and a controller;

[0045] The inverter unit includes n groups of three-phase inverters; the isolation unit includes n three-phase transformers; wherein n≥2;

[0046] The output filter unit includes three groups of filter capacitors;

[0047] The three-phase transformer includes a primary winding and a secondary winding;

[0048] The AC output ends of each group of three-phase inverters are respectively connected to the corresponding primary windings of the three-phase transformer;

[00...

Embodiment 2

[0056] This embodiment is based on Embodiment 1. In this embodiment, the disturbance voltage generating device further includes a chopper unit, and the chopper unit includes a power module and an energy consumption unit connected to the DC side of the inverter unit , when the DC side voltage rises beyond the protection fixed value, the power module is triggered to act, and the energy consumption unit releases energy to reduce the DC side voltage.

[0057] In particular, when the inverter unit fails to block the wave, the current on the secondary winding of the three-phase transformer connected in series between the power grid and the device under test will not disappear immediately, and the primary winding of the three-phase transformer will not disappear immediately. The current will continue to charge the DC side through the freewheeling diode of the inverter unit, causing the DC side voltage to rise abnormally until the power module of the chopper unit is triggered to act, r...

Embodiment 3

[0060] This embodiment is based on Embodiment 1. In this embodiment, the three-phase inverter is a three-phase full-bridge inverter with a two-level structure or a three-phase full-bridge inverter with a multi-level structure. The three-phase full-bridge inverter includes six bridge arms, each two of the bridge arms form a phase, and the AC output ends thereof are respectively connected to two ends of the corresponding phase of the primary winding of the three-phase transformer.

[0061] In this embodiment, the three-phase transformer preferably adopts a three-phase four-pole structure, a three-phase five-pole structure, or a three-phase group structure.

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Abstract

The invention discloses a disturbance voltage generating device for measuring impedance characteristics of a grid-connected equipment port. The disturbance voltage generating device comprises a rectification unit, an inversion unit, an isolation unit, an output filtering unit and a controller, the inversion unit comprises n groups of three-phase inverters; the isolation unit comprises a three-phase transformer; the alternating current output end of each group of three-phase inverters is respectively connected with a primary winding of the three-phase transformer; the secondary windings of the same phase of each three-phase transformer are connected in series to form a cascade branch, and the two ends of the cascade branch are connected to the output filtering unit, the device realizes the output voltage superposed wave of the inversion unit through the secondary cascade of the three-phase transformers on the output side, the equivalent switching frequency is improved, and the conversion efficiency is improved. High-precision control is realized to output harmonic voltage in a certain bandwidth range, the broadband impedance characteristic of a grid-connected equipment port can be directly and accurately measured, the switching frequency of each group of inverters is effectively reduced, the output capacity of the device is improved, the insulation and voltage resistance levels of an inversion unit and a rectification unit to the ground in the device can be reduced, and the size of the device is smaller.

Description

technical field [0001] The invention relates to the technical field of grid-connected equipment testing, in particular to a disturbance voltage generating device for measuring the impedance characteristics of a grid-connected equipment port. Background technique [0002] As the proportion of new energy power generation in the power system continues to increase, the "double high" characteristics of high proportion of new energy and high proportion of power electronic devices have become increasingly prominent, and the power industry has higher and higher requirements for the grid-connected performance of new energy power generation equipment. In this context, it is necessary to carry out extensive research on the interaction characteristics, closed-loop effects and impedance characteristics of new energy power generation equipment and the power grid, and to evaluate the adaptability, support and stability of new energy power generation equipment under various grid access condi...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H02M7/217H02M7/5387H02M1/12H02J3/38G01R27/02
CPCH02M7/217H02M7/5387H02M1/12H02J3/38G01R27/02Y02E10/56
Inventor 周党生梅松林黄晓陈志远
Owner SHENZHEN HOPEWIND ELECTRIC CO LTD