Variable-frequency flexible tuning device, half wavelength AC transmission system and control method of half wavelength AC transmission system

Abstract

The invention provides a variable-frequency flexible tuning device. The variable-frequency flexible tuning device comprises a rotation transformer, a DC driving motor and a current collection ring, wherein a rotor winding of the rotation transformer is connected with the current collection ring, and the DC driving motor is used for driving the rotation transformer so as to change a rotor rotational speed and a rotor side transmission power of the rotor of the rotation transformer. Compared with the prior art, the variable-frequency flexible tuning device provided by the invention has the advantages that the rotor rotational speed and the rotor side transmission power of the rotation transformer are adjusted by adjusting an output torque of the DC driving motor, and electric quantity parameters such as a frequency, voltage amplitude and a phase of an output signal of the variable-frequency flexible tuning device can be further flexibly adjusted.

Description

technical field [0001] The invention relates to the technical field of power electronics, in particular to a frequency conversion flexible tuning device, a half-wavelength AC transmission system and a control method thereof. Background technique [0002] The development of technologies such as photovoltaics and wind power has promoted intensive large-scale development in areas where resource conditions are not the best, thus making the transmission and implementation of ultra-long-distance, high-power electric energy have extensive significance and practical value. [0003] Half Wavelength AC Transmission (HWACT) refers to the ultra-long-distance three-phase AC transmission whose electrical distance of power transmission is close to one power frequency half wavelength, that is, 3000km (50Hz) or 2600km (60Hz). A half-wavelength AC line without loss is like an ideal transformer with a transformation ratio of -1.0. The voltage at the head end and the end voltage are the same an...

AI Technical Summary

Problems solved by technology

[0006] (1) The passive tuning circuit has relatively poor adaptability to system structure, operation mode or parameter changes, and it is easy to lose half-wavelength characteristics;

[0007] (2) The function of the passive tuning circuit is relatively single, which only solves the tuning problem, and cannot meet the development requirements of flexible and intelligent power grids;

[0008] (3) When a short-circuit fault occurs in a passive tuning circuit or a half-wavelength AC transmission line, it is easy to cause resonance and generate a high-amplitude overvoltage, which requires the line and equipment to increase the corresponding insulation requirements, or requires the installation of a corresponding overvoltage limiter measures to suppress the overvoltage of the line

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