DFIG direct current grid-connected power generation system based on RMC and torque control method of DFIG direct current grid-connected power generation system

Abstract

The invention discloses a DFIG direct current grid-connected power generation system based on an RMC. The DFIG direct current grid-connected power generation system comprises a plurality of DFIGs and a high-voltage direct current power grid; each DFIG is connected with a stator RMC converter and a rotor RMC converter; each stator RMC converter and the corresponding rotor RMC converter share one controller. Compared with a traditional DFIG grid-connected system, the DFIG system enables an industrial frequency transformer to be smaller in size and lighter in weight. According to the DFIG system, the number of levels of the converters is reduced, a voltage stabilizing capacitor with the large size is replaced by a filter capacitor with the small size and the light weight, and the system is simple in structure and stable in operation performance. The invention further discloses a torque control method of the system, through the synergistic effect of the stator RMC converters and the rotor RMC converters, the constant electromagnetic torque output by the DFIGs and the constant amplitude of air gap flux linkage are guaranteed, and the output active power and the input reactive power of the stator side and the rotor side of a motor are controlled to be equal.

Description

technical field [0001] The invention belongs to the technical field of wind power grid-connected power generation, and specifically relates to an RMC (reduced matrix converter)-based DFIG DC grid-connected power generation system and a torque control method thereof. Background technique [0002] With the increase of population and the development of economy, human beings' demand for energy is also increasing, and the traditional energy reserves are becoming increasingly exhausted, thus bringing about the problem of energy shortage. With the depletion of traditional energy sources, wind energy has become a very promising new energy source. In today's society, the wind power industry has become a pillar industry in the field of new energy sources. [0003] With the wide application of onshore wind farms, offshore wind farms are also developing continuously. Compared with onshore wind farms, offshore wind power has become an important sustainable energy source due to its advan...

AI Technical Summary

Problems solved by technology

This grid-connected system must use the sending end station to change the DFIG output power from AC transmission to DC transmission, and the sending end station needs to maintain a stable motor stator terminal voltage under different working conditions. The system structure is complex and the control is difficult.

In addition, the traditional converters used in HVDC have many conversion stages, which increases energy loss, and the use of electrolytic capacitors for voltage stabilization increases the volume and weight of the system, while reducing the reliability of the system

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