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A multi-level energy storage power conversion control device without AC and DC current sensors

A current sensor and power conversion technology, applied in harmonic reduction devices, AC networks to reduce harmonics/ripples, parallel feeding arrangements for a single network, etc. , to achieve the effect of suppressing switching sub-harmonics, reducing disturbance, and flexible device

Active Publication Date: 2018-10-16
STATE GRID CORP OF CHINA +2
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] The characteristic of multi-level power conversion is that the switching frequency is very high, generally around 18KHz. After the DC power is converted into AC power, the harmonic frequency is mainly the switching sub-frequency, and the low-order harmonics are very small. Due to the existence of high-frequency harmonics, and The stability of the power grid after the grid will be affected and the harm will be serious
Although the LC or LCL filtering method can reduce the injection of high-order harmonics into the power grid to a certain extent, it is easy to cause resonance, causing high-frequency harmonics to be injected into the power grid, and affecting the stability of the power grid after grid connection.
In addition, the measurement problems caused by the accuracy and stability of AC and DC sensors have always affected the performance of power conversion devices

Method used

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  • A multi-level energy storage power conversion control device without AC and DC current sensors
  • A multi-level energy storage power conversion control device without AC and DC current sensors
  • A multi-level energy storage power conversion control device without AC and DC current sensors

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Embodiment

[0045] A multi-level energy storage power conversion control device without an AC / DC current sensor in this embodiment, such as figure 1 As shown, the device is connected in series between the supercapacitor for storing non-grid-connected energy and the power grid. The device includes: grid-connected controller 1, charge and discharge controller 2, DC charge and discharge unit 3, multi-level power conversion Unit 4, wave trap 5.

[0046] The multi-level power conversion unit 4 of this embodiment is a three-level inverter circuit.

[0047] The DC charging and discharging unit 3, the three-level inverter circuit and the wave trap 5 are connected in series in sequence; the local terminal of the grid-connected controller 1 is connected to the communication terminal of the charging-discharging controller 2, and the communication terminal of the grid-connected controller 1 is connected to the charging terminal. The local terminal of the discharge controller 2 is connected.

[0048...

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Abstract

The invention relates to a multilevel energy storage power conversion control device without an AC / DC current sensor, and belongs to the technical field of power generation, power transformation or power distribution. The device is arranged between a non-grid-connection energy storage device and a power grid. The device comprises the following parts: a grid connection controller, a charge and discharge controller, a DC charge and discharge unit, a multilevel power conversion unit and a trap filter. The device can perform charge and discharge control on an energy storage system so that output voltage is more stable. The multilevel power conversion design is adopted so that conversion efficiency is high. The trap filter design is adopted to filter higher harmonic waves so that grid connection electric energy quality is great, generation of resonance is effectively suppressed by feedforward control calculation, the AC / DC sensor is eliminated and cost is lower.

Description

technical field [0001] The invention relates to a power conversion device without an AC and DC current sensor, and belongs to the technical field of power generation, power transformation or power distribution. Background technique [0002] Wind energy and solar energy are a huge amount of renewable energy. Under the encouragement of national policies, my country's renewable energy has developed rapidly. Among renewable energy sources, wind power development technology is the most mature and the development cost is the lowest. my country has planned to build dozens of wind power bases with one million kilowatts and nine ten million kilowatts. By the end of 2013, my country's installed capacity of wind power has taken the lead in the world, reaching 91,400 kilowatts. Due to cost and other reasons, my country's solar photovoltaic power generation started relatively late. With the reduction of the cost of photovoltaic power generation, it has developed rapidly in recent years....

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/38H02J3/01
CPCH02J3/01H02J3/38Y02E40/40
Inventor 韦磊赵新建王峰李国杰韩蓓
Owner STATE GRID CORP OF CHINA
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