Control system for reducing voltage unbalancedness of direct current bus series capacitor of energy storage system bidirectional converter

A technology of DC bus capacitors and bidirectional converters, which is applied in the direction of reducing asymmetry of multi-phase networks, eliminating/reducing asymmetry of multi-phase networks, and parallel feeding arrangement of single network, which can solve the problem of reducing the life of series capacitors and voltage , Current control performance decline, reduce the service life of electrolytic capacitors and other issues, to achieve the effect of prolonging service life, improving maintenance-free performance, and improving reliability

Inactive Publication Date: 2013-05-01
BEIJING HUADIAN TIANREN ELECTRIC POWER CONTROL TECH
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Problems solved by technology

[0003] However, in the long-term operation of the bidirectional converter, due to the difference in the capacity of the electrolytic capacitors and the influence of the equivalent series resistance inside the electrolytic capacitors, the voltage imbalance between the two series of electrolytic capacitors will inevitably occur only through the parallel connection of voltage equalizing resistors. Further aggravate the attenuation of the capacity of the two sets of electrolytic capacitors in series, reduce the service life of the electrolytic capacitors, and cause the output harmonics of the bidirectional converter to increase, the voltage and current control performance to declin

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  • Control system for reducing voltage unbalancedness of direct current bus series capacitor of energy storage system bidirectional converter
  • Control system for reducing voltage unbalancedness of direct current bus series capacitor of energy storage system bidirectional converter
  • Control system for reducing voltage unbalancedness of direct current bus series capacitor of energy storage system bidirectional converter

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Embodiment Construction

[0021] The technical solution of the present invention will be described in further detail below according to the accompanying drawings.

[0022] attached figure 1 The structure shown is a conventional converter, the main body is a three-phase half-bridge fully-controlled rectifier circuit, and the DC side is connected to two sets of capacitors connected in series, respectively C 1 and C 2 , the middle point is generally not grounded, and the two ends of the two sets of capacitors in series are respectively connected in parallel with high-precision, high-resistance voltage equalizing resistors R 1 and R 2 , the AC output of the rectifier circuit passes through the three-phase AC inductor L 1 , L 2 and L 3 Connect to the three-phase AC power grid.

[0023] The structure of the energy storage system bidirectional converter applying the present invention is shown in the attached figure 2 , in addition to the conventional converter module, the voltage detection circuit of...

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Abstract

The invention relates to a control system for reducing the voltage unbalancedness of a direct current bus series capacitor of an energy storage system bidirectional converter. By aiming at the problem that the voltage unbalancedness of the direct current bus series capacitor can be possibly generated after the energy storage system bidirectional converter operates for a long time, voltage balance compensation control strategies are adopted for guaranteeing the long-period, safe and stable operation of the energy storage system bidirectional converter. Through the adoption of the method, the voltage unbalancedness of the series capacitor can be effectively reduced, the free maintenance of the converter is enhanced, the uninterrupted operation capability of the converter is improved, and obvious economic benefits are realized.

Description

technical field [0001] The invention belongs to the technical field of energy storage systems, in particular to the technical field of bidirectional converter control of energy storage systems. Background technique [0002] At present, electrolytic capacitors are widely used in the DC bus of bidirectional converters in energy storage systems. The electrolytic capacitor used in the mainstream two-level bidirectional converter of the energy storage system generally has a withstand voltage rating of 450V, while the output voltage of the three-phase full-bridge uncontrolled rectification of the 380V AC grid is at least 540V, so the DC bus of the bidirectional converter Generally, two sets of electrolytic capacitors are connected in series, and the voltage balance of the series connected electrolytic capacitors is maintained through a certain high-precision, high-resistance grading resistor. [0003] However, in the long-term operation of the bidirectional converter, due to the ...

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Application Information

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IPC IPC(8): H02J3/26H02J3/38
CPCY02E40/50
Inventor 吴国荣鹿怀骥王思耕陈飞陈剑李志强
Owner BEIJING HUADIAN TIANREN ELECTRIC POWER CONTROL TECH
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