Feedforward control method for suppressing power oscillation of modularized voltage source type converter valve

Abstract

The invention provides a feedforward control method for suppressing power oscillation of a modularized voltage source type converter valve. The method comprises the steps of collecting the active power and passive power, three-phase voltage Usabc, three-phase current Isabc, upper bridge arm current ITabc, lower bridge arm current IBabc and direct current voltage Udc of the system side of the modularized voltage source type converter valve; performing DQ conversion on Usabc and Isabc, thus acquiring a system side voltage component usdq (usd, usq) and a feedback current component isDQ (IsD, IsQ); computing an outer ring active reference current IrD, and thus acquiring outer ring passive reference current IrQ; performing decoupling and PI control on IrD, IrQ and isDQ to acquire a reference voltage UrefDQ; acquiring a feedforward control signal according to the direct current voltage Udc; adding the reference voltage under a DQ shaft with the feedforward signal, thus acquiring a reference voltage Ureffabc for feedforward control; performing loop current suppression to acquire a conversion suppression voltage Uzabc under a statistic abc coordinate; and overlapping Ureffabc with Uzabc to acquire reference voltages of upper and lower bridge arms, and performing nearest level approximation modulation to acquire a switch control signal of the modularized voltage source type converter valve.

Description

technical field [0001] The invention relates to flexible direct current transmission technology, in particular to a feedforward control method for suppressing power oscillation of a modular voltage source type converter valve. Background technique [0002] Modular Multilevel Converter (MMC) adopts controllable turn-off power electronic devices and pulse width modulation (Pulse Width Modulation, PWM), which can realize independent control of active power and reactive power, and It is a novel multilevel converter topology that can supply power to passive networks, and has become a research hotspot in the current international power electronics field. The high voltage direct current (HVDC) system based on the modular voltage source converter valve can overcome the shortcomings of thyristor direct current, and connect new energy power plants (such as wind power, solar power, etc.) It has broad application prospects in fields such as distance load and construction of urban load ...

AI Technical Summary

Problems solved by technology

However, in the case of flexible DC converter valves with overhead lines, long distances, and low power transmission, DC voltage and power oscillations are prone to occur, which limits the application of high-power converter valves at low power levels. In order to expand the converter valve In the working range, to suppress the oscillation of DC voltage and power, it is necessary to suppress the power oscillation of the modular voltage source converter valve

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