Control method of energy supplementing power supply used for valve group test device

Abstract

The invention relates to a control method of an energy supplementing power supply used for a valve group test device. The method comprises following steps of adjusting output voltage of a rectification bridge Rec so as to allow the output voltage of the energy supplementing power supply to reach a predetermined value, and putting a parallel connection compensator LC2 and a serial connection compensator LC1; turning off an output switch Km and outputting energy that the valve group test device needs to provide when the output voltage of the energy supplementing power supply is fluctuated alongwith the voltage of an energy storage capacitor in a sub-module M; and after the test of the valve group test is finished or fails, skipping the output switch Km and locking the energy supplementing power supply. According to the invention, the energy supplementing power supply is enabled to provide power and voltage required for operation of the valve group test device, and the output voltage ofthe energy supplementing power supply is fluctuated along with the periodical fluctuation of the voltage of the sub-module M, so effects on the power grid caused by low-order harmonic waves generatedby the fact that the output voltage of the energy supplementing power supply is fluctuated along with the periodical fluctuation of the voltage of the sub-module M are greatly reduced.

Description

technical field [0001] The invention belongs to the technical field of power electronics, and in particular relates to a method for controlling an energy supplementary power supply of a valve group test device. Background technique [0002] As the demand for high-power power electronic products develops in the direction of higher voltage and larger power capacity, two-level or three-level technology can no longer meet the increasing demand for voltage and capacity. More and more high-power power Electronic products adopt modular multi-level topologies, for example, flexible DC transmission voltage source converters or chain static synchronous compensators in the field of high voltage and high power mostly adopt modular multi-level topologies. [0003] A valve group test device is needed to construct a test environment for voltage stress, current stress, and thermal stress that is the same or similar to the actual working condition for the sub-modules in the modular multileve...

AI Technical Summary

Problems solved by technology

When the valve group test device is in operation, the supplementary power supply needs to continuously provide energy to make the valve group test run stably. If the energy output by the supplementary power supply cannot be replenished to the valve group in time, the capacitor voltage of the sub-module of the valve group will drop rapidly. , the valve group test will not continue

[0004] Since the voltage of the energy storage capacitor in the sub-module of the valve group will have large periodic fluctuations during steady-state operation, including large fundamental frequency fluctuations and double fundamental frequency fluctuations, the output of the energy supplementary power supply at this time The voltage will also fluctuate greatly, and the output current and voltage contain more low-order harmonics. If the supplementary power supply has no measures to suppress low-order harmonics, the low-order harmonics will seriously affect the power grid power through the supplementary power supply. In addition, the voltage fluctuation of the energy storage capacitor in the sub-module of the valve group also puts forward strict requirements on the output regulation of the energy supplementary power supply

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