Directly-driven wind power generation system and mode for modulating SPWM inversion control signal in system

Abstract

The invention relates to a directly-driven wind power generation system and a mode for modulating an SPWM inversion control signal in the system. The directly-driven wind power generation system is characterized in that a high-inductance permanent magnet synchronous generator is arranged and coaxially connected with a wind turbine; an alternating current signal output end of the high-inductance permanent magnet generator is connected in series with a triphase uncontrollable rectifier; direct current output by the triphase uncontrollable rectifier is used as an input signal of a subsequent current type inverter; an output signal of the current type inverter is filtered by a wave filter and fed to an alternating current network as sinusoidal current; the current type inverter consists of a fully-controlled power electronic switch and a current source type full-bridge inverting circuit; and the fully-controlled power electronic switch uses a sinusoidal pulse-width modulating signal SPWM as a control signal. Under the condition of a low wind speed, the directly-driven wind power generation system can also generate power without needing a direct current capacitor of the convertor, simplifies a controlling system, improves the generating efficiency of the whole machine and reduces the cost.

Description

technical field [0001] The invention relates to an electric energy conversion system and a control method applied in a wind power generation system. Background technique [0002] The small wind power generation system below 50KW mainly adopts variable speed, direct drive permanent magnet synchronous generator and fixed pitch blade structure. In this structure, the permanent magnet synchronous generator usually adopts a low-inductance permanent magnet synchronous generator, and the motor is connected in turn with a rectifier, a capacitor of the DC link, and a voltage-type inverter VSI. The low-inductance permanent magnet synchronous generator can act as a voltage source due to its small internal resistance, and a voltage-source inverter controlled by PWM can be used to generate the required sinusoidal current. But the main disadvantages of this structure are: [0003] 1. The range of wind speed is limited [0004] Due to the voltage source composed of the low-inductance pe...

AI Technical Summary

Problems solved by technology

This greatly limits the range of wind speeds in which power can be fed back to the grid

For places where the wind speed is low for a long time, such a structure cannot effectively utilize the system equipment

[0005] 2. Expensive

Since the cost of the inverter controller is usually several times the cost of the generator, obviously, this greatly increases the system cost, and thus hinders the wider application of small grid-connected wind turbines

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