Three-phase voltage unbalance phase-locked loop based on decoupling control
A three-phase voltage and decoupling control technology, applied in the direction of automatic power control, electrical components, etc., can solve the problems of large storage space and poor control effect, achieve small calculation amount, good phase-locking performance, and save storage space Effect
Inactive Publication Date: 2013-11-13
SHENZHEN JINGFUYUAN TECH
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[0003] However, the existing delay control method needs to store the sampling point of the grid voltage, which requires a large storage space, and the positive sequence component and negative sequence component of the decomposed grid voltage are greatly affected by the grid voltage fluctuation, resulting in poor control effect
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[0024] The present invention proposes a phase-locked loop that completely eliminates the influence of voltage imbalance. Based on double-synchronous coordinate transformation and decoupling calculation, the phase-locking loop can be locked quickly and accurately even under fault conditions such as power grid voltage frequency mutation and single-phase grounding.
[0025] Such as figure 1 As shown, the PLL proposed by the present invention at least includes a first phase detector 11, a second phase detector 12, a third phase detector 13, a positive sequence voltage decoupling conversion calculation module 14, and a negative sequence voltage decoupling conversion calculation module. Module 15 , several low pass filters, full wave integrator 16 and PI controller 17 .
[0026] The first phase detector converts the three-phase voltage u a , u b and u c Transform the αβ coordinate system, suppress the influence of the zero sequence component and obtain the components of the posit...
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The invention discloses a three-phase voltage unbalance phase-locked loop based on decoupling control. The three-phase voltage unbalance phase-locked loop at least comprises a first phase discriminator, a second phase discriminator, a third phase discriminator, a positive sequence voltage decoupling conversion calculation module, a negative sequence voltage decoupling conversion calculation module, a plurality of low-pass filters connected with the positive sequence voltage decoupling conversion calculation module output end and the negative sequence voltage decoupling conversion calculation module output end, a full-wave integrator and a proportional integral (PI) controller. On the basis that a three-phase voltage signal is decomposed into a positive sequence component, a negative sequence component and a zero sequence component through the first phase discriminator, dq conversion is conducted under two coordinate axes of a positive sequence and a negative sequence respectively, a conversion result under a negative dq coordinate system is used for removing a second harmonic generation component generated when a positive dq coordinate system is converted, and therefore effects of the negative sequence component on a phase-locked result are restrained. By means of the three-phase voltage unbalance phase-locked loop, the positive sequence component can be tracked effectively when the three-phase signal is unbalanced, calculation amount of the phase-locked loop is small, and the phase-locked loop is especially suitable for a real-time control system.
Description
technical field [0001] The invention relates to digital phase-locked technology, in particular to a three-phase voltage unbalanced phase-locked loop based on decoupling control. Background technique [0002] In inverter systems such as photovoltaics, when the grid voltage is unbalanced and distorted, it is necessary to accurately and quickly detect the phase and frequency signals of the positive sequence fundamental component of the grid voltage to achieve low voltage ride through, and it is necessary to decompose the positive sequence component of the grid voltage and For the negative sequence component, the positive sequence controller and the negative sequence controller are designed respectively, and the low voltage ride through control of the grid voltage is realized by using the delay control method. [0003] However, the existing delay control method needs to store the sampling point of the grid voltage, which requires a large storage space, and the positive sequence ...
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Inventor 刘晓红陈恒留
Owner SHENZHEN JINGFUYUAN TECH