Method for feeding in electrical power by means of a wind power installation

Patent metadata

Field	Value
Publication number	US-11705737-B2
Application number	US-202117387481-A
Country	US
Kind code	B2
Filing date	Jul 28, 2021
Priority date	Jul 29, 2020
Publication date	Jul 18, 2023
Grant date	Jul 18, 2023

Abstract

A method for feeding electrical power into an electrical supply network using an inverter-controlled infeed unit is provided. The infeed unit has an inverter arrangement with a plurality of inverters to generate an output power and feed same into the network. Each inverter has an associated isolating switch to galvanically isolate the respective inverter from the network. Each inverter has a circuit composed of switches to generate an output current using pulsed actuation. Each inverter generates a variable partial power, and the output power is a sum of all partial powers. Depending on the output power, one or more of the inverters are operated as active inverters that respectively generates a partial power. The other inverters are operated as passive inverters that do not generate a partial power. One or more of the passive inverters are operated as blocked inverters and remain galvanically connected to the network.

First claim

The invention claimed is:

1. A method for feeding electrical power into an electrical supply network using an inverter-controlled infeed unit, comprising:
feeding, by an inverter arrangement including a plurality of inverters, an output power into the electrical supply network;
selectively galvanically isolating each inverter of the plurality of inverters from the electrical supply network using an associated isolating switch of a plurality of isolating switches, each inverter of the plurality of inverters being associated with a circuit including a plurality of switches configured to generate a sinusoidal output current using pulsed actuation of the circuit;
generating a plurality of partial powers by the plurality of inverters, respectively;
summing the plurality of partial powers to produce the output power;
depending on the output power, operating one or more first inverters of the plurality of inverters as active inverters that respectively generate a partial power, and
depending on the output power, operating one or more second inverters of the plurality of inverters as passive inverters that respectively do not generate a partial power, wherein one or more of the passive inverters are operated as blocked inverters and remain galvanically coupled to the electrical supply network.

2. The method as claimed in claim 1 , wherein the inverter-controlled infeed unit is a wind power installation or a storage system.

3. The method as claimed in claim 1 , comprising:
suppressing the pulsed actuation to prevent each blocked inverter from respectively generating the partial power;
ending the suppressing using a triggering signal; and
in response to ending the suppressing using the triggering signal, generating the respective partial power by the blocked inverter.

4. The method as claimed in claim 3 , comprising:
operating each blocked inverter in a standby mode in which each blocked inverter functions as an active inverter with the pulsed actuation suppressed.

5. The method as claimed in claim 2 , wherein:
the wind power installation or the storage system is associated with a maximum power that is an upper limit for the output power,
all of the plurality of inverters are operated as active inverters and respectively generate the plurality of partial powers when the output power reaches the maximum power, and
one or more of the plurality of inverters are operated as passive inverters when the output power is below the maximum power at least by a predeterminable power interval, wherein the maximum power, the output power and the power interval are checked as an apparent power, active power or reactive power, and/or implemented by checking an infeed apparent current, an infeed active current or an infeed reactive current.

6. The method as claimed in claim 1 , comprising:
operating one or more passive inverters as blocked inverters that remain galvanically connected to the electrical supply network; and
operating one or more further passive inverters as isolated inverters that are respectively galvanically isolated from the electrical supply network using respective isolating switches.

7. The method as claimed in claim 6 , wherein:
a filter circuit is provided for each inverter to filter the output current generated by the inverter, and
the filter circuit in the isolated inverters is galvanically isolated from the electrical supply network using an isolating switch of the inverter.

8. The method as claimed in claim 1 , comprising:
selecting an inverter as active inverter or passive inverter and/or selecting the passive inverter as a blocked inverter or isolated inverter depending on:
a magnitude of an apparent current to be fed in,
a magnitude of an active current to be fed in,
a magnitude of a reactive current to be fed in,
at least one detected loss of the inverter arrangement,
a detected temperature of the inverter arrangement,
an intermediate circuit voltage of a joint DC voltage intermediate circuit of the inverter arrangement,
a network voltage of the electrical supply network, and/or
a fluctuation range of the output power.

9. The method as claimed in claim 1 , comprising:
modelling a behavior of the inverter arrangement using a model; and
selecting inverters as active inverters or passive inverters depending on a behavior of the model.

10. The method as claimed in claim 9 , comprising:
selecting passive inverters as blocked inverters or isolated inverters depending on a behavior of the model.

11. The method as claimed in claim 1 , comprising:
modelling a behavior of the inverter arrangement using a model;
simulating the model using a test configuration; and
specifying the test configuration by a selection of inverters as active inverters or as passive inverters.

12. The method as claimed in claim 11 , comprising:
specifying the test configuration by a selection of the passive inverters as blocked inverters or as isolated inverters;
varying test configurations;
simulating the model for each test configuration to obtain a simulation result for each test configuration; and
selecting a new configuration depending on the simulation result.

13. The method as claimed in claim 12 , comprising:
selecting the new configuration by evaluating boundary conditions.

14. The method as claimed in claim 1 , comprising:
selecting inverters as active inverters or as passive inverters for a level of the output power;
operating the inverter-controlled infeed unit or simulating a model using the selecting of the inverters;
detecting an efficiency measure as a result of operating the inverter-controlled infeed unit or simulating the model;
storing the selection, the level of the output power and the efficiency measure as a reference configuration; and
after a change in the level of the output power, selecting the inverters as active inverters or as passive inverters depending on at least one reference configuration.

15. The method as claimed in claim 14 , comprising:
storing at least one property or boundary condition as the reference configuration.

16. The method as claimed in claim 1 , comprising:
detecting respective inverter temperatures of the plurality of inverters; and
selecting the inverter as an active inverter or as a passive inverter depending on the inverter temperature or a comparison of the inverter temperatures.

17. The method as claimed in claim 16 , wherein the inverter temperature is a temperature of the circuit of the inverter and the selection of the inverter is changed depending on the inverter temperatures.

18. The method as claimed in claim 1 , wherein
each inverter of the plurality of inverters has a DC voltage intermediate circuit having an intermediate circuit voltage, and
an intermediate circuit control system configured to keep the intermediate circuit voltage in a voltage band is provided for the blocked inverters.

19. The method as claimed in claim 1 , wherein
when an active inverter changes to a passive inverter, the partial power generated by the active inverter before the change is distributed across remaining active inverters,
a transition specification is provided for the distribution across the remaining active inverters, and
the transition specification specifies a temporal reduction profile for reducing the partial power of the changing active inverter, and/or the transition specification respectively specifies a temporal increase profile for increasing the partial powers of the remaining active inverters.

20. The m

Assignees

• Wobben Properties Gmbh

Inventors

• Brombach Johannes
• Fredewess Tobias

Classifications

• H02J2103/30

  Simulating, planning, modelling, reliability check or computer assisted design [CAD] of electric power networks · CPC title

• H02J2101/28

  Wind energy · CPC title

• H02J3/46 Primary

  Controlling the sharing of generated power between the generators, sources or networks · CPC title

• H02J3/381

  Dispersed generators · CPC title

• H02J2203/20

  Electricity · mapped topic