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Secondary Ripple Suppression Method of Capacitive Energy Storage Type Single-phase Rectifier Based on Virtual Impedance

A virtual impedance, capacitor energy storage technology, applied in electrical components, output power conversion devices, etc., can solve problems such as reducing capacitance and inductance values, increasing voltage or current stress of power switching devices, increasing system complexity and cost, etc. , to achieve the effect of improving the service life and reducing the secondary ripple component

Active Publication Date: 2021-06-01
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

Therefore, active filtering can reduce the capacitance and inductance value by increasing the capacitor voltage or the inductor current ripple, thereby effectively improving the power density of the entire system, but this method increases the voltage or current of the power switching device in the bidirectional DC converter stress
At the same time, the traditional active filtering scheme needs to collect more voltage and current signals, which increases the complexity and cost of the entire system

Method used

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  • Secondary Ripple Suppression Method of Capacitive Energy Storage Type Single-phase Rectifier Based on Virtual Impedance
  • Secondary Ripple Suppression Method of Capacitive Energy Storage Type Single-phase Rectifier Based on Virtual Impedance
  • Secondary Ripple Suppression Method of Capacitive Energy Storage Type Single-phase Rectifier Based on Virtual Impedance

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Embodiment 1

[0040] In order to solve the above-mentioned technical problems, the implementation of the present invention provides a method for suppressing secondary ripple of a capacitive energy storage type single-phase rectifier based on virtual impedance, comprising the following steps:

[0041] 101: Model the bidirectional DC-DC converter connected to the energy storage capacitor and battery, and obtain the open-loop equivalent input impedance of the two converters;

[0042] In order to simplify the analysis, the power switch in the converter is regarded as an ideal switch, its on-resistance and voltage drop are ignored, and the switching action is considered to be completed instantaneously. At this time, the converter is in a switching period T S There will be two different switching states to obtain the equivalent input impedance of the two DC converters.

[0043] 102: Connect the virtual impedance Z in series with the filter inductance of the DC-DC converter S ;

[0044]In order ...

Embodiment 2

[0047] The scheme in embodiment 1 is further introduced below in conjunction with specific drawings and examples, see the following description for details:

[0048] Embodiments of the present invention are based on traditional active filtering, according to figure 2 A new control method is proposed to suppress the secondary power frequency fluctuation of the bus voltage on the DC side and the charging voltage and current of the secondary battery.

[0049] When there is a secondary ripple on the output DC side bus of the rectifier, the bus capacitor, energy storage capacitor and the auxiliary bidirectional DC-DC converter connected to it, the battery and the bidirectional DC-DC converter connected to it can be equivalent to A parallel structure of three impedances, such as figure 2 shown. According to Kirchhoff's current theorem KCL, the equivalent input impedance of each unit in the system determines the distribution of the secondary ripple current in each unit. At this t...

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Abstract

The invention discloses a method for suppressing the secondary ripple of a capacitor energy storage type single-phase rectifier based on a virtual impedance, which comprises the following steps: modeling a bidirectional DC-DC converter connected to an energy storage capacitor and a storage battery to obtain two conversions The open-loop equivalent input impedance of the converter; the virtual impedance Z is connected in series with the filter inductance of the DC‑DC converter S ;Virtual impedance Z in series with the filter inductor S It can be realized by introducing inductive current feedback in the control link in the bidirectional DC converter for energy storage capacitor; the method makes the equivalent input impedance of the bidirectional DC converter for energy storage capacitor present low impedance characteristics in the secondary power frequency , which is lower than the equivalent impedance of the battery converter and the bus capacitor, which is conducive to the absorption of the secondary ripple of the bus by the energy storage capacitor; The inductor current signal of the bidirectional DC converter has the advantages of simple structure, easy control and high robustness.

Description

technical field [0001] The invention relates to the field of control technology of power electronics technology, in particular to a method for suppressing secondary ripple of a capacitive energy storage type single-phase rectifier based on virtual impedance. Background technique [0002] With the increase of car ownership per capita in the world, the use of fossil energy and the emission of greenhouse gases are increasing, making global climate and environmental problems increasingly serious. New energy vehicles use renewable energy as the power source and can achieve clean and zero-pollution emission operation. It is considered to be one of the new modes of transportation that can effectively alleviate the energy crisis and environmental pollution. In new energy vehicles, when the single-phase AC power grid is rectified by the single-phase rectifier to charge the energy source, especially the battery, there will be a secondary ripple voltage on the DC bus side of the single...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H02M1/14
CPCH02M1/143
Inventor 张云刘强强宋天宝方剑毕宇轩
Owner TIANJIN UNIV