Three-level active power filter (APF) reference current detection method suitable for distorted or unbalanced situation

A reference current and source filter technology, which is applied in the direction of measuring current/voltage, instruments, measuring devices, etc., can solve the problem of low detection accuracy and achieve the effect of improving detection accuracy

Inactive Publication Date: 2014-10-29
哈尔滨同为电气股份有限公司
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  • Application Information

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Problems solved by technology

[0005] In order to solve the problem of low detection accuracy of the APF reference current detection method based on the instantaneous power theory when the grid voltage is non-sinusoidal or unbalanced, the present invention proposes a three-level active filter reference current detection suitable for distortion or unbalanced conditions method

Method used

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  • Three-level active power filter (APF) reference current detection method suitable for distorted or unbalanced situation
  • Three-level active power filter (APF) reference current detection method suitable for distorted or unbalanced situation
  • Three-level active power filter (APF) reference current detection method suitable for distorted or unbalanced situation

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specific Embodiment approach 1

[0025] DETAILED DESCRIPTION One, a method for detecting a reference current of a three-level active filter applicable to distortion or imbalance, is characterized in that it comprises the following steps:

[0026] Step 1. Connect the A-phase voltage u in the public connection point between the APF and the power grid sa , B-phase voltage u sb and C-phase voltage u sc The voltage u of the common connection point between the APF and the power grid under the αβ coordinates is obtained by changing the three phases into two phases sα and u sβ ;

[0027] Step 2. The A-phase current i in the load current La , B-phase current i Lb and C-phase current i Lc The load current i under the αβ coordinates is obtained by changing three phases into two phases Lα and i Lβ ;

[0028] Step 3: Calculate the voltage u of the public connection point between the APF and the power grid under the αβ coordinates sα and u sβ Filtered by a highly selective filter to obtain the fundamental compon...

specific Embodiment approach 2

[0037] Specific Embodiment 2. According to claim 1, a three-level active filter reference current detection method suitable for distortion or unbalanced conditions is characterized in that, in step 1, the common connection point between the APF and the grid Phase A voltage u in sa , B-phase voltage u sb and C-phase voltage u sc The voltage u of the common connection point between the APF and the power grid under the αβ coordinates is obtained by changing the three phases into two phases sα and u sβ The process is:

[0038] u sα u sβ = 2 3 1 - 1 / 2 1 ...

specific Embodiment approach 3

[0039] Specific Embodiment 3. According to claim 1, a method for detecting a reference current of a three-level active filter under conditions of distortion or unbalance is characterized in that, in step 2, the A-phase current i in the load current is La , B-phase current i Lb and C-phase current i Lc The load current i under the αβ coordinates is obtained by changing three phases into two phases Lα and i Lβ The process is;

[0040] i Lα i Lβ = 2 3 1 - 1 / 2 1 / 2 ...

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Abstract

The invention discloses a three-level active power filter (APF) reference current detection method suitable for a distorted or unbalanced situation, relates to the field of three-level parallel APF reference current detection under a power grid distorted or unbalanced situation, and solves the problem of low detection accuracy of the APF reference current detection method based on an instantaneous power theory under the non-sine or unbalanced situation of power grid voltage. The method is used for performing resonant current separation. The detection method can run effectively in an alpha-beta coordinate system under a voltage distorted or unbalanced situation, and high compensation characteristic is realized for an APF. Based on a high-selectivity filter (HSF), the method can be applied to a distorted or unbalanced power grid environment, and resonant compensation and power factor correction can be effectively performed through the APF, thereby increasing the reference current detection accuracy and ensuring that the power grid current and the power grid voltage are at the same phase. The method is suitable for detecting the reference current of a three-level APF under a distorted or unbalanced situation.

Description

technical field [0001] The invention relates to the field of three-level parallel APF reference current detection under the condition of grid distortion or imbalance. Background technique [0002] With the extensive application of nonlinear loads, such as diode rectifier bridges, thyristor rectifiers, and speed control devices, the power system has been seriously polluted. Usually, passive LC filters are used to eliminate current harmonics and improve power factor. However, passive filters have many disadvantages, such as fixed compensation capacity, large size, and resonance problems. To address the appeal, active filters have been studied to eliminate harmonics and overcome other power quality problems. [0003] On the other hand, diode-clamped three-level converters have been widely used in industrial fields, such as PWM rectification, motor driving, and uninterruptible power supplies. It has the following advantages: low distortion of output voltage and current, small...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G01R19/00
Inventor 王北南武健刘金生孔繁宇贾远伟徐殿国何崇飞
Owner 哈尔滨同为电气股份有限公司
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