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Current source type frequency converter power grid current observation method based on SVPWM mode

A current source type and power grid current technology, applied in the direction of instruments, electrical components, circuit devices, etc., can solve the problems of increasing engineering application costs and reducing system reliability, so as to improve system reliability, reduce system cost, and save AC Effect of current sensor

Active Publication Date: 2016-10-26
SHANGHAI MERCHANT SHIP DESIGN & RES INST
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Additional AC current sensors, on the one hand, increase the cost of engineering applications, and on the other hand, reduce the reliability of the system

Method used

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  • Current source type frequency converter power grid current observation method based on SVPWM mode
  • Current source type frequency converter power grid current observation method based on SVPWM mode
  • Current source type frequency converter power grid current observation method based on SVPWM mode

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Embodiment Construction

[0019] Based on the analysis of the virtual flux linkage observation idea and the mathematical model of the frequency converter, the present invention designs a grid current observer through a method of state reconstruction, and realizes the control without an AC current sensor.

[0020] The essence of the non-grid current sensor control technology is based on the idea of ​​virtual flux observation, and the grid current is observed according to the DC bus current and the switching function. First estimate the inverter side current i according to the DC bus current and switching function wa ,i wb ,i wc .

[0021] According to the definition of grid virtual flux linkage, considering that the three-phase grid is balanced and completely sinusoidal, the following formula can be obtained from a mathematical point of view:

[0022]

[0023] Equation (1) shows that the essence of the virtual flux linkage observation is the two components e of the grid voltage in the αβ coordinat...

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PUM

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Abstract

The invention discloses a current source type frequency converter power grid current observation method based on an SVPWM (space vector pulse width modulation) mode. Three-phase power grid balance and complete sine are considered based on a power grid virtual flux linkage definition and a current source type frequency converter mathematical model, two components of a power grid voltage in an [alpha][beta] coordinate system are e<[alpha]> and e<[beta]>, L<f> is an inductance value of a filter inductor, w<s> is power grid angle frequency, C<f> is a capacitance value of a filter capacitor, i<s[alpha]> and i<s[beta]> are components of a power grid current in the [alpha][beta] coordinate system, frequency converter side output currents i<w[alpha]> and i<w[beta]> are components of frequency converter side currents i<wa>, i<wb> and i<wc> in the [alpha][beta] coordinate system, and an observation formula of the power grid current is shown in the description.

Description

technical field [0001] The invention belongs to the technical field of frequency converter control, and in particular relates to a current source type frequency converter grid current observation method based on a SVPWM modulation mode. Background technique [0002] Frequency converters can be divided into current source type frequency converters and voltage source type frequency converters in terms of topology. In order to achieve the corresponding control objectives, such as motor speed control and optimal control, current sensors are essential. The topology of the current source inverter is as follows: figure 1 As shown, in order to achieve the corresponding control objectives, the current existing technology usually uses additional current sensors to measure the corresponding variables, such as AC side current and DC side current, such as figure 1 shown. The extra AC current sensor increases the cost of engineering application on the one hand, and reduces the reliabil...

Claims

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Application Information

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IPC IPC(8): H02J3/00G06F17/13G06F19/00
CPCG06F17/13G16Z99/00H02J3/00H02J2203/20
Inventor 张亮亮乐小龙翁爽谢家纯张毅谢珉陈默
Owner SHANGHAI MERCHANT SHIP DESIGN & RES INST