Single carrier control method applicable to cascaded SVG

A control method and single-carrier technology, applied in the direction of converting irreversible DC power input into AC power output, flexible AC power transmission system, reactive power adjustment/elimination/compensation, etc., can solve the difficult problems of realization and achieve excellent performance Harmonic elimination performance, stable control of grid-connected current, and the effect of switching action balance

Inactive Publication Date: 2012-12-26
HUNAN UNIV
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  • Summary
  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Benefits of technology

The present inventicn describes an improved method for regulating electrical energy supply between multiple sources or loads connected through a circuit breaker (CB). This helps prevent damage caused by overvoltage faults that could occur during normal operation. It achieves this by utilising three separate carriers instead of just one altogether. By doing so, there are fewer components used than usual while still maintain good efficiency. Additionally, the use of triple phased signals allows for better control of both AC voltages and currents without affecting other parts within the system's structure. Overall, these improvements improve safety measures and reduce costs associated with electricity distribution systems.

Problems solved by technology

This patented describes various technical problem addressed by this patents relating to current multilevel modulation techniques such as CPC (Cascading Power Compensator) technology applied to electricity networks. These systems require large numbers of power components due to their complexity and lack flexibility. Therefore there needs an improved method called Multiplexer Controllable Insulators (MCIs).

Method used

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  • Single carrier control method applicable to cascaded SVG
  • Single carrier control method applicable to cascaded SVG
  • Single carrier control method applicable to cascaded SVG

Examples

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Embodiment Construction

[0039] figure 1 It is a five-level cascaded SVG main circuit structure diagram. The single-phase full-bridge inverter circuit is used as the H-bridge unit, and two H-bridge units are directly connected in series at the AC end. The three-phase link adopts a star connection, and then connects to the power grid through a connecting reactor. Among them, the single-phase full-bridge inverter circuit includes two left and right parallel bridge arms and a DC side capacitor branch, each bridge arm is composed of two power devices connected in series, and the DC side capacitor branch is connected in parallel with the bridge arm. Each cascaded H-bridge inputs two PWM signals from the control system, respectively controls the on-off of the power devices of the two bridge arms, and outputs a DC side voltage signal. The cascaded SVG can perform dynamic reactive power compensation and harmonic control for nonlinear loads in the medium and high voltage distribution network, and improve the...

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Abstract

The invention discloses a single carrier control method applicable to a cascaded SVG (Static Var Generator). The method comprises the following steps: acquiring the instantaneous values of power network voltage, grid-connected current, reactive instruction current and the direct current side voltage of each cascaded H bridge unit through a detection link and generating an SVG voltage modulating signal through voltage current double loop control; rounding off the voltage modulating signal, comparing the 'decimal part' acquired by rounding off with a single-channel triangular carrier signal to acquire one path of pulse signal P1, and adding the P1 and the 'integer part' acquired by rounding off to obtain one path of multilevel pulse signal; and distributing on-off action to a semiconductor power device according to the multilevel pulse signal, the current on-off state of a cascaded branch, the sequencing of direct current side voltage and the polarity of the grid-connected current so as to stabilize the direct current side voltage of each cascaded H bridge and control the grid-connected current. The harmonic characteristic of the method is more excellent than that of carrier phase-shift modulation; the on/off of power devices in the cascaded H bridges can be controlled by a single-channel triangular carrier; and the method is easy to implement.

Description

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Claims

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Application Information

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Owner HUNAN UNIV
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