Active damping control device and method for DC side resonance of DC transmission system

Abstract

The invention discloses a DC power transmission system DC side resonance active damping control device and method. The device comprises a resonance damping control unit used for controlling resonance damping of a DC power transmission system DC network through controlling a resonance damping control coefficient to acquire a first output signal; a DC voltage stabilization control unit used for controlling DC voltage stabilization of a DC power transmission system to acquire a second output signal; a current inner ring decoupling control unit used for controlling active power of the DC power transmission system to acquire a third output signal; and an NLM signal modulation unit used for superposing the first output signal, the second output signal and the third output signal to acquire a modulation signal, wherein the modulation signal after NLM modulation is used for providing a triggering pulse signal for an IGBT of an MMC of the DC power transmission system. The device is advantaged in that a purpose of DC side voltage and current inhibition of the modular multi-level converter type DC power transmission system can be realized on the condition that extra loss and hardware cost do not increase.

Description

technical field [0001] The invention relates to the field of DC side resonance suppression of a DC power transmission system, in particular to an active damping control device and method for suppressing DC side resonance of a modularized multilevel DC power transmission system. Background technique [0002] For the two-level DC microgrid and AC microgrid system, due to the turn-on and turn-off of the power electronic device IGBT, a high-frequency harmonic component near the switching frequency will be generated on the DC side or the AC side, and the high-frequency harmonic component is DC side or ac side LC equivalent network provides the excitation source to excite the resonance. When the frequency of the excitation source is equal to the natural frequency of the system, the voltage or current will be amplified, and the resonance will be excited at this time. [0003] At present, there is another resonance phenomenon on the DC side in the DC transmission system or the DC m...

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Problems solved by technology

However, these methods have great disadvantages: the first two methods not only greatly increase the hardware cost and system volume and additional hardware power loss, but also cannot completely suppress the DC side resonance phenomenon, and may stimulate new Oscillation at the frequency point; and the essential idea of ​​the third method is to suppress the peak value of the impedance frequency response characteristic of the DC network through the idea of ​​loop shaping to suppress the resonance. However, it can only suppress the resonance at a specific frequency, and there are It may increase the possibility of resonance excitation at other frequency points. In addition, because the frequency response of the DC network in actual engineering is difficult to estimate and the natural frequency cannot be determined, the feasibility of implementation is not high, and it is difficult to promote in a large area.

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