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Cascaded H-bridge converter control method under power grid harmonic background

A control method and converter technology, which are applied in AC networks to reduce harmonics/ripples, harmonic reduction devices, power transmission AC networks, etc., can solve problems such as reducing the stability and robustness of control systems

Active Publication Date: 2021-02-02
GUANGXI UNIV
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  • Application Information

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Problems solved by technology

Commonly used extraction tools include low-pass filters and band-pass filters. In order to filter low-order harmonics well enough, commonly used low-pass filters, or band-pass filters such as second-order generalized integrators and reduced-order generalized integrators The cutoff frequency of the controller can only be designed as low as possible, thus reducing the stability and robustness of the entire control system

Method used

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  • Cascaded H-bridge converter control method under power grid harmonic background
  • Cascaded H-bridge converter control method under power grid harmonic background
  • Cascaded H-bridge converter control method under power grid harmonic background

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Embodiment Construction

[0054] A cascaded H-bridge converter control device under the background of grid harmonics, including filter inductor L, equivalent resistance R, n-level cascaded H-bridge converter, signal acquisition module and control module; grid current passes through etc. Effective resistor R, filter inductor L and n-level cascaded H-bridge converter;

[0055] The n-level cascaded H-bridge converter is composed of n single-phase H-bridge units cascaded, and each H-bridge unit is composed of 4 IGBTs with anti-parallel diodes, 1 DC capacitor and 1 resistor; each 2 Two IGBTs with anti-parallel diodes are connected in series to form a bridge arm, and the two bridge arms are connected in parallel; the DC capacitor is connected in parallel with the two bridge arms; the resistance is connected in parallel with the DC capacitor;

[0056] The signal acquisition module acquires the output AC current signal i of n-level cascaded H-bridge converters sa , grid voltage signal u s , and the DC side v...

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Abstract

The invention provides a cascaded H-bridge converter control method under a power grid harmonic background, and provides an improved unit vector directional direct current control strategy under a natural coordinate system by taking improvement of the control performance of a converter under the power grid harmonic background as a target and taking a single-phase cascaded H-bridge converter as anobject so as to enable the output current power factor to be controllable, and the total harmonic distortion rate of the current to meet the requirements of a power grid. According to the control method, the fundamental frequency component of the power grid is rapidly extracted by using a delay signal cancellation method, and an ideal unit vector under a natural coordinate is solved for orientation, so that an accurate current reference value is obtained, and direct current control is carried out by using a proportional resonance controller with excellent performance, and the influence of theharmonic background on the control system is further eliminated through distortion voltage proportion feedforward.

Description

technical field [0001] The invention belongs to the technical field of converter control, and in particular relates to a cascaded H-bridge converter control method under the background of grid harmonics. Background technique [0002] Cascaded H-bridge multilevel converters are widely used in high-voltage DC transmission, motor drive, and flexible AC because of their modular design, simple control, and the ability to use lower-voltage power devices to achieve higher-voltage applications. Power transmission, new energy power generation grid connection and other fields. In recent years, the power system has a trend of power electronics: there are more and more nonlinear loads, the penetration rate of renewable energy in the traditional power grid is getting higher and higher, and various forms of micro-grids and weak power grids have emerged one after another. This trend As a result, more low-order harmonic components inevitably appear in the traditional power grid. When the ...

Claims

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Application Information

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IPC IPC(8): H02J3/38H02J3/36H02J3/01H02M7/00H02M7/797
CPCH02J3/381H02J3/36H02J3/01H02M7/00H02M7/797H02M1/007Y02B70/10Y02E40/40Y02E60/60
Inventor 杨达亮陈爽杨林航陈思远
Owner GUANGXI UNIV
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