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PWM rectifier DC bus voltage ripple suppression method based on virtual impedance under three-phase voltage imbalance condition

A DC bus voltage and three-phase voltage technology, applied in the direction of irreversible AC power input conversion to DC power output, electrical components, output power conversion devices, etc., can solve the problem of high dependence on mathematical models, increase system cost and complexity , Ripple suppression effect is difficult to meet the predetermined requirements, etc., to achieve the effect of broadening application scenarios, reducing dependence, and avoiding additional losses

Pending Publication Date: 2022-05-10
TIANJIN UNIV
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0009] Known DC bus voltage ripple suppression technology, one type relies on additional power electronic converters to buffer the pulsating power, which increases the cost and complexity of the system; the other type controls the output pulsating power of the three-phase PWM rectifier to be zero. The model dependence is high, when the system parameters change, the ripple suppression effect is difficult to meet the predetermined requirements

Method used

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  • PWM rectifier DC bus voltage ripple suppression method based on virtual impedance under three-phase voltage imbalance condition
  • PWM rectifier DC bus voltage ripple suppression method based on virtual impedance under three-phase voltage imbalance condition
  • PWM rectifier DC bus voltage ripple suppression method based on virtual impedance under three-phase voltage imbalance condition

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Embodiment 1

[0049] An adaptive watermark embedding method based on local quality evaluation, comprising the following steps:

[0050] (1) Assume that the original DC bus capacitor C of the three-phase PWM rectifier is 200μF. The control block diagram of the present invention is as figure 1 shown.

[0051](2) Next, in order to determine the virtual capacitance c in step 1 i value so that the virtual capacitor c i Increase from 400μF to 3200μF, according to formula (9) to draw the Bode diagram of the system as figure 2 shown.

[0052] (3) by figure 2 It can be seen from the medium-amplitude-frequency curve that, with the virtual capacitance c i increases, the lower the gain of the system at 100Hz, and combined with formula (5), it can be known that the system at 2f f The voltage ripple will be smaller. but by figure 2 From the phase-frequency curve, it can be seen that with the virtual capacitance c i The shear frequency of the system increases slightly, but the phase margin de...

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Abstract

The invention relates to a PWM rectifier DC bus voltage ripple suppression method based on virtual impedance under a three-phase voltage imbalance condition, and belongs to the technical field of power electronic control. An existing direct current bus voltage ripple suppression method of a PWM rectifier under the three-phase voltage unbalanced working condition depends on a mathematical model of the PWM rectifier under the initial condition unbalanced working condition, so that the accuracy degree of the mathematical model when parameters change is not fully considered, and when grid-side inductance parameters change, the direct current bus voltage ripple suppression effect is reduced. According to the invention, the output impedance of the three-phase PWM rectifier is changed to suppress voltage ripples, so that the use of a mathematical model of the rectifier is avoided. By adopting the method provided by the invention, the voltage ripples of the direct-current bus can be fully suppressed, the robustness of the system to parameter change is enhanced, and meanwhile, good dynamic and steady-state performance is obtained.

Description

technical field [0001] The invention belongs to the technical field of control of power electronics, and in particular relates to a method for suppressing voltage ripples of a PWM rectifier direct current busbar under a virtual impedance-based three-phase voltage unbalanced working condition. Background technique [0002] The popularity of traditional fuel vehicles has provided great convenience for people's travel, but it has also brought serious environmental pollution problems. At the same time, in order to find alternative energy sources for fossil energy, experts and scholars have carried out extensive and in-depth research on renewable and non-polluting new energy sources, and new energy vehicles have gradually entered the public eye. [0003] In order to realize the charging of new energy vehicles, power electronic converters are essential. As the interface between the AC grid and the power battery of electric vehicles, the three-phase PWM rectifier has the advantage...

Claims

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Application Information

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IPC IPC(8): H02M7/04H02M1/14
CPCH02M7/04H02M1/14
Inventor 张云宋天宝朱新山
Owner TIANJIN UNIV
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