Fast active power output reduction system of doubly-fed induction generator and method thereof

Patent metadata

Field	Value
Publication number	US-12119778-B2
Application number	US-202117308929-A
Country	US
Kind code	B2
Filing date	May 5, 2021
Priority date	Sep 10, 2020
Publication date	Oct 15, 2024
Grant date	Oct 15, 2024

Abstract

The present invention discloses a FPR system of DFIG, comprising a DC chopper circuit made up of a fully-controlled power switching device and a dump resistor first connected in series and then connected to the positive and negative poles of the DC-link; the fully-controlled power switching device is driven by a power switching device driver; the power switching device driver comprises a first inverting adder, a first PI controller and a PWM modem; the positive and negative input ends of the first inverting adder receive the real-time DC-link voltage signal and its threshold value respectively, and the output end of the first inverting adder is connected to the input end of the first PI controller; the output end of the first PI controller is connected to the input end of the PWM modem; the PWM modem outputs the pulse signal to the control end of the fully-controlled power switching device.

First claim

What is claimed is:

1. A Fast active Power output Reduction (FPR) system, comprising:
a pitch servo system,
a DC-link and a rotor-side converter (RSC) and
a grid-side converter (GSC) connected in parallel across positive and negative poles of the DC-link; and
a DC chopper circuit, which includes a dump resistor and a fully controlled power switching device, wherein the dump resistor and the fully controlled power switching device are first connected in series and then connected to the positive and negative poles of the DC-link, respectively; the fully controlled power switching device being driven by a power switching device driver; the power switching device driver comprising a first inverting adder, a first PI controller and a PWM modem;
positive and negative input ends of the first inverting adder receiving a real-time DC-link voltage signal and a threshold value of the real-time DC-link voltage signal respectively, and the output end of the first inverting adder being connected to an input end of the first PI controller; an output end of the first PI controller being connected to an input end of the PWM modem; and the PWM modem out putting the pulse signal to the control end of the fully controlled power switching device.

2. The FPR system according to claim 1 , wherein the RSC is driven by an RSC dual closed-loop vector control unit; the RSC dual closed-loop vector control unit comprising an RSC inner current loop and an RSC outer power loop; wherein the RSC outer power loop consists of two branches, wherein one branch includes (a) a power conversion unit that converts a wind turbine generator (WTG) rotor speed to a WTG stator active power reference, (b) a second inverting adder and (c) a second PI controller that are connected in sequence; the other branch includes (a) a third inverting adder and (b) a third PI controller that are connected in sequence; output ends of the two branches are connected to the input end of the RSC inner current loop via a first multiplexer switch, a control end of the first multiplexer switch receives a control signal from an upper-level controller; the power conversion unit receives a signal of a real-time rotor speed and outputs the WTG stator active power reference according to a wind turbine MPPT curve; the second inverting adder, whose positive input end is connected to the output end of the power conversion unit, and whose negative input end receives a signal of actual stator active power; positive and negative input ends of the third inverting adder receive an FPR command value and an actual doubly-fed induction generator (DFIG) active power output to the grid respectively; two data input ends of the first multiplexer switch receive the active current references generated from the second PI controller and the third PI controller respectively.

3. The FPR system according to claim 2 , wherein the GSC is driven by a GSC dual closed-loop vector control unit; the GSC dual closed-loop vector control unit comprising a GSC inner current loop and a GSC outer voltage loop; wherein the GSC outer voltage loop consists of a DC-link voltage conversion unit that converts a rotor speed deviation to a DC-link voltage reference, a fourth inverting adder, a fifth inverting adder, a fourth PI controller and a second multiplexer switch; a real-time rotor speed and an optimal rotor speed under an MPPT mode are input to positive and negative input ends of the fourth inverting adder, the fourth inverting adder outputs the rotor speed deviation to the DC-link voltage conversion unit, the DC-link voltage conversion unit outputs the DC-link voltage reference; two data input ends of the second multiplexer switch receive a rated DC-link voltage and the DC-link voltage reference generated from the DC-link voltage conversion unit respectively; an output end of the second multiplexer switch is connected to a positive input end of the fifth inverting adder; a negative input end of the fifth inverting adder receives signal of the real-time DC-link voltage, the fifth inverting adder outputs a DC-link voltage deviation to the fourth PI controller; the fourth PI controller outputs a reference of active current flowing into GSC to the GSC inner current loop; a control end of the second multiplexer switch receives a control signal from an upper-level controller.

4. The FPR system according to claim 3 , wherein a pitch servo system comprising a pitch servo driver that drives a pitch servo motor, a wind power coefficient calculator, a pitch angle command lookup table, a sixth inverting adder, a fifth PI controller and a third multiplexer switch;
the wind power coefficient calculator receiving an FPR command value and a maximum mechanical power of WTG operating under an MPPT mode and outputting a wind power coefficient to the pitch angle command lookup table; wherein the wind power coefficient being calculated in the condition that a captured mechanical power input by WTG is equal to the FPR command;
the pitch angle command lookup table outputting a pitch angle command corresponding to a calculated wind power coefficient;
positive and negative input ends of the sixth inverting adder receiving signals of a real-time rotor speed and a rated rotor speed respectively, the output end of the sixth inverting adder being connected to the input end of the fifth PI controller; the fifth PI controller outputting a pitch angle reference; two data input ends of the third multiplexer switch receiving the pitch angle command from the pitch angle command lookup table and the pitch angle reference from the fifth PI controller; data output end of the third multiplexer switch being connected to the pitch servo driver; the control end of the third multiplexer switch receiving a control signal from an upper-level controller.

Assignees

• Univ Tianjin

Inventors

• Zhu Jiebei
• Deng Zhaoshun
• Li Feng

Classifications

• H02J2101/28

  Wind energy · CPC title

• H02P21/00

  Arrangements or methods for the control of electric machines by vector control, e.g. by control of field orientation · CPC title

• H02P9/00

  Arrangements for controlling electric generators for the purpose of obtaining a desired output · CPC title

• H02J3/00

  Circuit arrangements for AC mains or AC distribution networks · CPC title

• F05B2270/32

  Wind speeds · CPC title