# US 2024/0200533 A1 · Method, Apparatus, Device And System For Controlling An Oscillation Damping Caused By A Series Compensation For A Wind Power Plant

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- Number: US 2024/0200533 A1
- Document ID: US20240200533A1
- Status: Published application
- Kind: A1
- Application number: 18/533,037
- Filed: 2023-12-07
- Published: 2024-06-20
- Earliest claimed: 2022-12-09
- Assignees: Vertiv New Energy Co., Ltd.
- Applicants: Vertiv New Energy Co., Ltd.
- Inventors: Xiaogang CHU; Tao ZHANG; Yufan XI
- Web page: https://patentgrep.com/patent/US20240200533A1

## CPC

- F03D 7/044: {with PID control}
- H02J 3/46: Controlling the sharing of generated power between the generators, sources or networks
- H02J 3/0014: for preventing or reducing power oscillations in networks
- H02J 2101/28: Wind energy
- Y02E 10/76: Power conversion electric or electronic aspects
- F03D: WIND MOTORS
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

A method, an apparatus, a device and a system for controlling an oscillation damping caused by a series compensation for a wind power plant are provided. The method includes: extracting, a first dynamic small signal from first relevant parameters causing power oscillation, inputting the first dynamic small signal to a PID controller, and feeding an output control parameter from the PID to a rotor voltage controller as a first feedforward term; obtaining, according to second relevant parameters causing sub-synchronous oscillation, a virtual voltage, and feeding into a rotor voltage controller as a second feedforward term; and extracting a third dynamic small signal from third relevant parameters causing the oscillation of a rotor current loop and then performing phase and amplitude compensations on the third dynamic small signal, and feeding the output of the POD controller into the given position of a rotor current controller as a third feedforward term.

## Claims

### Claim 1

A method for controlling an oscillation damping caused by a series compensation for a wind power plant, wherein the method comprises:
extracting, by a filter, a first dynamic small signal from first relevant parameters causing power oscillation during the operation of a doubly-fed generator, inputting the first dynamic small signal to a proportional-integral-differential (PID) controller, and feeding an output control parameter from the PID controller into a rotor voltage controller as a first feedforward term;
obtaining, from second relevant parameters causing sub-synchronous oscillation during the operation of the doubly-fed generator, a virtual voltage corresponding to a second dynamic small signal, and feeding the virtual voltage into the rotor voltage controller as a second feedforward term;
using a power oscillation damping (POD) controller, extracting a third dynamic small signal from third relevant parameters causing the oscillation in a rotor current loop during the operation of the doubly-fed generator and performing phase and amplitude compensations on the third dynamic small signal, and feeding an output of the POD controller into a given position of a rotor current controller as a third feedforward term.

### Claim 2 (depends on 1)

The method according to claim 1, further comprising:
acquiring a sub-synchronous slip voltage and a sub-synchronous slip frequency during the operation of the doubly-fed generator;
multiplying the sub-synchronous slip voltage, the sub-synchronous slip frequency and a stator-rotor turn ratio to obtain a fourth feedforward term; and
feeding the fourth feedforward term into an output terminal of the rotor current controller, wherein the output terminal of the rotor current controller is connected to the rotor voltage controller.

### Claim 3 (depends on 1)

The method according to claim 1, further comprising:
obtaining a rotor voltage by the rotor voltage controller based on the first feedforward term, the second feedforward term and an output of the rotor current controller, wherein the rotor voltage comprises a rotor voltage for a d-axis and a rotor voltage for a q-axis; and
inputting the rotor voltage to a phase locked loop (PLL), performing phase and amplitude compensations on a power component of the first dynamic small signal, multiplying the power component subjected to the phase and amplitude compensations by a gain coefficient and feeding into an angular frequency integrator of the PLL, and calculating corresponding grid voltage angle by using the PLL.

### Claim 4 (depends on 2)

The method according to claim 2, further comprising:
obtaining a rotor voltage by the rotor voltage controller based on the first feedforward term, the second feedforward term and an output of the rotor current controller, wherein the rotor voltage comprises a rotor voltage for a d-axis and a rotor voltage for a q-axis; and
inputting the rotor voltage to a phase locked loop (PLL), performing phase and amplitude compensations on a power component of the first dynamic small signal, multiplying the power component subjected to the phase and amplitude compensations by a gain coefficient and feeding into an angular frequency integrator of the PLL, and calculating corresponding grid voltage angle by using the PLL.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the second relevant parameters include a rotor current or a stator current.

### Claim 6 (depends on 5)

The method according to claim 5, wherein the second relevant parameters include the rotor current, and the obtaining the virtual voltage corresponding to the second dynamic small signal from the second relevant parameters causing sub-synchronous oscillation during the operation of the doubly-fed generator and feeding the virtual voltage into the rotor voltage controller as the second feedforward term comprises:
extracting the second dynamic small signal from the rotor current by the POD controller, performing phase compensation on the second dynamic small signal and multiplying by a gain coefficient to obtain the virtual voltage corresponding to the second dynamic small signal, and feeding the obtained virtual voltage into the rotor voltage controller as the second feedforward term; or
multiplying the rotor current by a sum of a virtual resistance and a virtual impedance to obtain the virtual voltage corresponding to the second dynamic small signal, and feeding the obtained virtual voltage into an output terminal of the rotor current controller as the second feedforward term, wherein the output terminal of the rotor current controller is connected to the rotor voltage controller.

### Claim 7 (depends on 1)

The method according to claim 1, further comprising:
obtaining a rotor voltage by the rotor voltage controller based on the first feedforward term, the second feedforward term and an output of the rotor current controller, wherein the rotor voltage comprises a rotor voltage for a d-axis and a rotor voltage for a q-axis;
inputting a stator active power and a reference active power to a power controller, and processing by an inertia device and a filter the obtained corresponding angular frequency change and feeding into the power controller through a negative feedback loop; and
inputting the rotor voltage to a phase-locked loop (PLL), feeding an output of the power controller to an angular frequency integrator of the PLL, and calculating by the PLL a corresponding voltage angle of a power grid.

### Claim 8 (depends on 2)

The method according to claim 2, further comprising:
obtaining a rotor voltage by the rotor voltage controller based on the first feedforward term, the second feedforward term and an output of the rotor current controller, wherein the rotor voltage comprises a rotor voltage for a d-axis and a rotor voltage for a q-axis;
inputting a stator active power and a reference active power to a power controller, and processing by an inertia device and a filter the obtained corresponding angular frequency change and feeding into the power controller through a negative feedback loop; and
inputting the rotor voltage to a phase-locked loop (PLL), feeding an output of the power controller to an angular frequency integrator of the PLL, and calculating by the PLL a corresponding voltage angle of a power grid.

### Claim 9 (depends on 1)

The method according to claim 1, wherein the filter is a washout filter and a transfer function of the washout filter is expressed as:
wherein S represents a differential operator, and TW represents a predetermined time constant.

### Claim 10 (depends on 1)

The method according to claim 1, wherein the first relevant parameters comprise a stator active power Pfb for a d-axis and a stator reactive power Qfb for a q-axis, and the rotor voltage controller comprises a rotor voltage controller for the d-axis and a rotor voltage controller for the q-axis.

### Claim 11 (depends on 1)

The method according to claim 1, wherein the third relevant parameters comprise a rotor positive sequence voltage for a d-axis and a rotor positive sequence voltage for a q-axis, and the rotor voltage controller comprises a rotor voltage controller for the d-axis and a rotor voltage controller for the q-axis.

### Claim 12 (depends on 1)

The method according to claim 1, wherein the POD controller comprises a gain unit with a gain coefficient K, a washout filter, and at least one phase compensator.

### Claim 13 (depends on 10)

The method according to claim 10, wherein the POD controller comprises a gain unit with a gain coefficient K, a washout filter, and at least one phase compensator.

### Claim 14

An apparatus for controlling an oscillation damping caused by a series compensation for a wind power plant, wherein the apparatus comprises:
a power oscillation suppression module, configured to extract, by a filter, a first dynamic small signal from first relevant parameters causing power oscillation during the operation of a doubly-fed generator, input the first dynamic small signal to a proportional-integral-differential (PID) controller, and feed an output control parameter from the PID controller into a rotor voltage controller as a first feedforward term;
a sub-synchronous oscillation suppression module, configured to obtain, from second relevant parameters causing sub-synchronous oscillation during the operation of the doubly-fed generator, a virtual voltage corresponding to a second dynamic small signal, and feed the virtual voltage into the rotor voltage controller as a second feedforward term; and
a current oscillation suppression module, configured to extract a third dynamic small signal from third relevant parameters causing the oscillation in a rotor current loop during the operation of the doubly-fed generator and perform phase and amplitude compensations by a power oscillation damping (POD) controller, and feed an output of the POD controller into a given position of a rotor current controller as a third feedforward term.

### Claim 15 (depends on 14)

A wind power generation system, comprising:
the apparatus for controlling an oscillation damping caused by a series compensation for a wind power plant according to claim 14; and
a doubly-fed generator configured to operate under control of the apparatus for controlling an oscillation damping caused by a series compensation for a wind power plant.