Active signal injection method for distance measurement function of MMC type direct current deicing device

Abstract

The invention discloses an active signal injection method for a distance measurement function of an MMC type direct current ice melting device. The method comprises the following steps: detecting current and voltage of the ice melting device; when the current or the voltage exceeds a preset threshold value, judging that a fault occurs and switching to a fault recovery state; determining parameter information of a to-be-injected signal in a modulation stage while keeping direct current control through a fault current limiting strategy; according to the to-be-injected signal parameter information and the sub-module capacitor voltage rated value, the switching number of sub-modules of upper and lower bridge arms is calculated, and target signal injection is carried out; and obtaining amplitude and frequency characteristic parameters of the target signal, and outputting a measurement signal. According to the invention, the purpose of injecting the voltage characteristic signal into the line by the converter port is realized by directly setting the voltage sine reference value to act on the switching of the sub-modules, and then the fault distance measurement method can be realized by using the voltage signal of the specific frequency band.

Images