Alternating-current excitation system and PWM control method of grid-side converter of alternating-current excitation system

Abstract

The invention relates to the field of power electronics and power transmission control, in particular to an alternating-current excitation system and a PWM control method of a grid-side converter of the alternating-current excitation system. The grid-side converter in the system comprises a plurality of grid-side modules which are connected in parallel, and each grid-side module is connected withan isolation type excitation transformer of the same type. According to the method, triangular carrier waves of all the grid-side modules are sequentially subjected to phase shifting by a set angle and compared with modulated waves of all the grid-side modules, and driving pulses corresponding to the grid-side modules are generated. Due to the fact that the excitation transformers on a grid side have no phase shift, after the triangular carrier waves are compared with the modulated waves, the driving pulses of all the grid-side modules are only staggered by the phase shift angle of the triangular carrier waves, and output harmonic waves are subjected to phase shift superposition, so the harmonic amplitude of total currents after parallel connection is reduced. The non-phase-shift isolationtransformers are used in the invention, so the design and production cost of the transformers is reduced through the non-phase-shift design, and a precision requirement is reduced; and a parallel circulation path is blocked through the isolation type design, so the problem of circulation is avoided.

Description

technical field [0001] The invention relates to the field of power electronics and electric drive control, in particular to a PWM control method for an AC excitation system and a grid-side converter thereof. Background technique [0002] In recent years, the grid-connected capacity of new energy grid-connected generator sets has been increasing. Due to the randomness of wind power and photovoltaic power generation, higher requirements have been placed on the peak-shaving and frequency-regulating capabilities of the grid. As the best tool for peak-shaving and valley-filling Pumped storage power station. As a comprehensive auxiliary management tool for the power grid, the pumped storage power station uses water energy conversion as a carrier to provide energy storage services and multi-working-condition dispatching operations for the system, and undertakes peak regulation, valley filling, frequency regulation, phase regulation, emergency backup, and blackout operations in the ...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a PWM control method for an AC excitation system and its grid-side converter, which is used to solve the problem that the existing method of reducing grid-side harmonics is relatively difficult

Images