Off-grid double-fed wind power generation system and maximum wind energy capture method thereof

Abstract

The invention provides an off-grid double-fed wind power generation system and a maximum wind energy capture method thereof. The power generation system comprises a double-fed generator, a rotor side converter, a load side converter, a bidirectional DC / DC (direct current) converter, a load side variable-current controller, a rotor side variable-current controller, a DC / DC variable-current controller and the like. The load side variable-current controller adopted by the invention can calculate a stator current reference value required for realizing the maximum wind energy capture according to the wind turbine speed and a maximum power curve, input a deviation between the stator current reference value and a feedback value to a proportional integral controller, produce a control voltage of the load side converter and generate a space vector PWM (pulse width modulation) signal to drive a power switch device of the load side converter. The rotor side converter can control the stator voltage of the double-fed generator to maintain at a rated value, and the load side converter can control the stator output power of the double-fed generator, thus the problem that output voltage stabilization and maximum wind energy capture cannot be simultaneously realized in the existing off-grid double-fed wind power generation system can be solved, and the wind energy utilization rate and economic benefit of the generating system can be improved.

Description

technical field [0001] The invention relates to an off-grid double-fed wind power generation system and a method for capturing maximum wind energy thereof, and belongs to the transformation technology of the off-grid type double-fed wind power generation system and a method for capturing maximum wind energy thereof. Background technique [0002] Wind power generation is an effective way to solve the current energy shortage and environmental pollution problems. According to whether it is connected to the grid, it can be divided into two types: grid-connected and off-grid. For remote areas where the power grid is difficult to cover and where wind energy resources are abundant, if an off-grid wind power generation system is built according to local conditions, the cost of laying long-distance transmission lines or long-distance transportation of fuel can be avoided, and it can also meet the production and living needs of local residents. Promote economic and cultural developmen...

AI Technical Summary

Problems solved by technology

[0007] 1. The generator capacity is close to the load capacity, and the power generation system loses the support of the infinite power grid. The rotor-side converter of the double-fed generator is mainly used to control the stator voltage of the double-fed generator to maintain it at the rated value, and can no longer participate power regulation;

[0008] 2. After the stator voltage of the doubly-fed generator is determined, the output current of the stator is determined by the load current, so the output power of the stator is determined by the load power instead of changing according to the wind speed, and the maximum wind energy capture cannot be achieved, and the wind energy conversion efficiency is low

Therefore, the existing control scheme can only maintain the output voltage of the power generation system at the rated value, while the output power of the power generation system is completely determined by the load and cannot track changes in wind speed. The power generation system does not have the maximum wind energy capture capability

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