Stator-free voltage measurement vector control method for direct-driven wind power converter

Abstract

A stator-free voltage measurement vector control method for a direct-driven wind power converter comprises a stator current calculation link, an initial flux linkage calculation link, a flux linkage phase locking link, a reference current calculation link and a current closed-loop control link. The stator current calculation link collects three-phase stator currents Isa, Isb and Isc and converts the three-phase stator currents Isa, Isb and Isc into stator currents Isalpha and Isbeta on an alpha-beta coordinate system and stator currents Isd and Isq on a DQ coordinate system; in the initial flux linkage calculation link, seven zero vectors of delta T0 time are output, the generator angular frequency omega 0 and the flux linkage angle initial value theta psi 0 at the allowable starting moment are determined in eight stages, and an allowable starting identifier ST_Per of a machine-side converter is output; in the flux linkage phase locking link, after ST_Per = 1, phase locking is carriedout on the basis of omega0 and theta psi 0, and the angular frequency omega of the generator and the flux linkage angle theta psi d are output; the reference current calculation link outputs stator reference currents IsdRef and IsqRef on the DQ coordinate system; and in the current closed-loop control link, a PI regulator is adopted to carry out closed-loop control on stator current on the DQ coordinate system, and stator control voltages Usca and Uscbeta on the alpha-beta coordinate system and stator control voltages Uscd and Uscq on the DQ coordinate system are output.

Description

technical field [0001] The invention relates to a vector control method without stator voltage measurement for a direct drive wind power converter. Background technique [0002] In recent years, with the vigorous promotion and development of green energy, my country's wind power industry has developed rapidly, and its cumulative installed capacity and annual new installed capacity both rank first in the world. With the development of onshore low-wind-speed wind farms and the rapid development of offshore wind power, a consensus has been reached on the use of large-megawatt wind turbines for onshore and offshore wind power. The power level basically starts from 4MW, and direct drive based on permanent magnet synchronous generators is generally used. Technical route, the converter adopts a three-phase voltage AC-DC-AC bidirectional converter. Due to the influence of the industrial chain, most of the current high-power offshore direct-drive wind turbines still follow the 690V ...

AI Technical Summary

Problems solved by technology

The 690V low-voltage technical route generally adopts the resistor divider non-isolation scheme, and the potential safety hazards of this scheme gradually become prominent when the voltage level is getting higher and higher.

[0004] Patent 201510755713.3 "A three-phase converter model predictive control method without voltage sensor", discloses a model predictive control method of converter without voltage sensor based on quadratic programming algorithm optimization, which can reduce the amount of calculation , reduce the difficulty of parameter setting, but the control object is only the grid with fixed frequency, and the initial value of the flux linkage of the control method is not considered; , He Yikang, etc.) proposed a three-phase PWM rectifier vector control technology based on grid virtual flux linkage without grid voltage sensor. Before the control method runs, the initial value of virtual flux linkage in the control method is obtained by outputting zero vectors of several PWM cycles. , only applicable to grids with fixed frequency, and when applied to large megawatt offshore direct-drive wind power converters, continuously outputting zero vectors of several PWM cycles will cause serious overcurrent problems

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