A new lcl filter and its design method

A design method and filter technology, applied in harmonic reduction devices, AC networks to reduce harmonics/ripples, electrical components, etc., to achieve good resonance peaks, increase flexibility, and suppress resonance peaks.

Active Publication Date: 2019-08-13
DALIAN UNIV OF TECH
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, it is more accurate and flexible to use fractional-order capacitors to form LCL filters for filtering, which cannot be achieved by traditional integer-order design methods.

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  • A new lcl filter and its design method
  • A new lcl filter and its design method
  • A new lcl filter and its design method

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Embodiment Construction

[0017] The specific embodiments of the present invention will be described in detail below in combination with the accompanying drawings and the technical solutions of the description.

[0018] The first step is to preliminarily determine the capacitance value C and the inductance value L in the circuit according to the design method of the integer-order LCL filter.

[0019] The second step is to determine the transfer function expression of the output current to the input voltage in the fractional-order LCL filter circuit and the relationship between the resonance frequency and the fractional-order parameters.

[0020] According to the circuit theory and the fractional order LCL filter circuit, the attachment shown in formula (1) is obtained figure 1 The state equation of the circuit diagram, the formula (1) represents the state equation of the fractional-order LCL filter circuit, wherein, the capacitance element adopts the fractional-order element, and the current-voltage re...

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Abstract

The invention discloses a novel LCL filter and a design method therefor, and belongs to the design field of a passive filter. Capacitance and inductance parameters are selected firstly according to a conventional LCL filter design method; next, a fractional order LCL filter circuit is designed; a transfer function and resonant frequency of an output current to an input voltage are obtained through the fractional order LCL filter circuit; and finally, the novel LCL filter is obtained by selecting an inductance order alpha and a capacitance order beta of the fractional order LCL filter. The fractional order LCL filter obtained by adopting the modeling method of the fractional order device is better in filtering effect; by virtue of the addition of the fractional order number, the design of the filter can be more flexible; and in addition, a guiding significance for more widely applying more fractional order devices to the filter is played in the future.

Description

technical field [0001] The invention proposes a novel LCL filter composed of fractional-order devices and a design method thereof, belonging to the field of passive filter design. Background technique [0002] The research on the LCL filter shows that the attenuation rate of the LCL filter in the low frequency band is -20dB / decade, and the attenuation rate of the LCL filter in the high frequency band increases to -60dB / decade. Obviously, the filtering performance of the high-frequency LCL filter is good, and it can be used in the active filter to filter out the harmonics at the switching frequency. However, there is an inherent resonance peak in the LCL filter, which will cause the harmonics at this frequency to be in an undamped state, and the harmonics at this frequency cannot be effectively suppressed. [0003] The research results of the mathematical model of the actual capacitance show that the actual capacitance is of fractional order in nature, but the order of the f...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02J3/01H03H7/01
CPCH02J3/01H03H7/01Y02E40/40
Inventor 李冠林孙恩泽
Owner DALIAN UNIV OF TECH
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