Wind power generation high-voltage direct current grid-connected system based on open coil structure and control method thereof

Abstract

The invention discloses a wind power generation high-voltage direct current grid-connected system based on an open coil structure. The wind power generation high-voltage direct current grid-connected system comprises a permanent magnetism synchronous wind driven generator, two generator side converters, two direct current boosters and a controller, wherein the permanent magnetism synchronous wind driven generator is of the open coil structure, and each direct current booster is composed of an electric reactor, an inverter, a transformer and a rectifier in a sequentially connected mode. According to the wind power generation high-voltage direct current grid-connected system based on the open coil structure, the open coil permanent magnetism synchronous wind driven generator is used, the two double-level three-phase controllable full-bridge converters are used for controlling the permanent magnetism synchronous wind driven generator, three-level modulation is achieved, voltage stress of converter capacity and voltage stress of switching elements are reduced, and system cost can be reduced. The wind power generation high-voltage direct current grid-connected system based on the open coil structure is simple in structure, low in cost and high in operational efficiency. The invention further discloses a method for controlling the system. According to the method, the better PWM technology of the vector control strategy is used, therefore, current harmonic contents inside the generator can be reduced, and the generator can better operate.

Description

technical field [0001] The invention belongs to the technical field of wind power generation, and in particular relates to a wind power generation high-voltage DC grid-connected system based on an open winding structure and a control method thereof. Background technique [0002] Energy is an important material basis for the production of human beings and the development of society. With the gradual depletion of non-renewable energy sources such as coal and oil, and the pollution problems caused by coal and oil are becoming more and more serious, it is necessary for all countries in the world to find new Clean and renewable energy is already an urgent task. As a renewable new energy, wind energy has a broad exploration prospect due to its huge reserves, clean and pollution-free. [0003] With the development and utilization of wind energy, the global wind power generation has maintained rapid and continuous growth for many years. The permanent magnet direct drive wind turbi...

AI Technical Summary

Problems solved by technology

Among the existing technical solutions, there is a solution to divide the voltage in series by switching tubes, but there is a technical problem of equalizing the voltage of the switching tubes, and there is also a cascading solution through the H bridge, which has the disadvantage of complex system structure

At the same time, the traditional system uses three-phase AC power transmission. As the capacity of offshore wind power continues to increase, the capacitive effect between the AC transmission cables will generate greater and greater losses, which not only limits the transmission capacity but also limits the transmission distance.

[0005] Based on the above considerations, someone proposed a DC grid-connected system based on open-winding permanent magnet synchronous motors, such as figure 2 As shown, the system uses a permanent magnet synchronous motor to generate power, passes through a back-to-back double PWM converter, then passes through an AC booster for high voltage, and finally passes through a rectifier to transmit electric energy to the DC bus. It is easy to see that the system The electric energy is merged into the DC grid through two converters, a transformer and a rectifier. It has a complex structure and a large number of equipment, resulting in low system operation efficiency and high cost.

Images