# US 10,374,538 B2 · Harmonic control of a converter

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- Number: US 10,374,538 B2
- Document ID: US10374538B2
- Status: Granted
- Kind: B2
- Application number: 16/178,631
- Filed: 2018-11-02
- Published: 2019-05-09
- Granted: 2019-08-06
- Earliest claimed: 2017-11-07
- Assignees: Siemens Gamesa Renewable Energy A/S
- Applicants: Siemens Gamesa Renewable Energy A/S
- Inventors: Nuno Miguel Amaral Freire; Yashan Hu; Zhan-Yuan Wu
- Web page: https://patentgrep.com/patent/US10374538B2

## CPC

- H02J 3/01: Arrangements for reducing harmonics or ripples
- H02J 3/381: {Dispersed generators}
- H02M 1/12: Arrangements for reducing harmonics from AC input or output
- H02P 9/02: Details {of the control}
- H02P 9/30: using semiconductor devices
- H02P 9/42: to obtain desired frequency without varying speed of the generator
- H02P 29/50: Reduction of harmonics
- F03D 7/0272: {by measures acting on the electrical generator}
- H02J 2101/28: Wind energy
- H02M 1/0025: {Arrangements for modifying reference values, feedback values or error values in the control loop of a converter}
- H02P 2101/15: for wind-driven turbines
- Y02E 10/76: Power conversion electric or electronic aspects
- Y02E 40/40: Arrangements for reducing harmonics
- H02J: ELECTRIC POWER NETWORKS; CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P)
- H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- F03D: WIND MOTORS
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION

## Abstract

Provided is an arrangement for determining an operation parameter reference for controlling a generator side converter portion coupled to a generator, in particular of a wind turbine, the arrangement comprising: an arithmetic element configured to derive a fundamental current error by subtracting a, in particular unfiltered, generator output current from a sum of a fundamental current reference and at least one harmonic current reference; a fundamental current controller adapted to determine a fundamental operation parameter reference based on the fundamental current error; at least one other arithmetic element configured to derive at least one harmonic current error by subtracting a, in particular band pass filtered according to the harmonics, generator output current from the at least one harmonic current reference; at least one harmonic current controller configured to determine at least one harmonic operation parameter reference based on the harmonic current error.

## Claims

### Claim 1

An arrangement for determining an operation parameter reference for controlling a generator side converter portion coupled to a generator of a wind turbine, the arrangement comprising:
an arithmetic element configured to derive a fundamental current error by subtracting an unfiltered, generator output current from a sum of a fundamental current reference and at least one harmonic current reference;
a fundamental current controller adapted to determine a fundamental operation parameter reference based on the fundamental current error;
at least one other arithmetic element configured to derive at least one harmonic current error by subtracting a band pass filtered according to the harmonics, generator output current from the at least one harmonic current reference;
at least one harmonic current controller configured to determine at least one harmonic operation parameter reference based on the harmonic current error;
still another arithmetic element configured to determine the operation parameter reference as sum of the fundamental operation parameter reference and the at least one harmonic operation parameter reference.

### Claim 2 (depends on 1)

The arrangement according to claim 1, wherein the operation parameter reference is a voltage reference for controlling the generator side converter portion.

### Claim 3 (depends on 1)

The arrangement according to claim 1, wherein the harmonic current reference comprises an oscillation corresponding to N times a fundamental electrical frequency of the generator, wherein N is a natural number larger than 2,
wherein the harmonic current reference is different from zero.

### Claim 4 (depends on 2)

The arrangement according to claim 2, wherein the fundamental voltage reference and the harmonic voltage reference are given in a fundamental dq-frame rotating with the fundamental electrical frequency of the generator.

### Claim 5 (depends on 1)

The arrangement according to claim 1, wherein the fundamental current controller comprises two PI-controller, to determine the fundamental operation parameter reference using for each of the d-component and the q-component of the fundamental current error in the fundamental dq-frame one PI-controller of the two PI-controllers.

### Claim 6 (depends on 1)

The arrangement according to claim 1, wherein the harmonic current controller comprises:
a transformation module configured to transform the harmonic current error in the fundamental dq-frame into a harmonic dq-frame, the harmonic dq-frame rotating with the respective multiple of the fundamental frequency;
two PI-controllers configured to receive the components of the harmonic current error in the harmonic positive sequence dq-frame as inputs;
a backtransformation module configured to backtransform the outputs of the PI-controllers into in the fundamental dq-frame, in order to determine the harmonic operation parameter reference; the harmonic current controller further comprising:
two PI-controllers configured to receive the components of the harmonic current error in the harmonic negative sequence dq-frame as inputs and corresponding transformation module and backtransformation module.

### Claim 7 (depends on 1)

The arrangement according to claim 1, further comprising:
an electrical speed estimator configured and connected to estimate an electrical rotational speed and/or an electrical angle of the generator based on the generator output current and in particular further based on the unfiltered fundamental operation parameter reference.

### Claim 8 (depends on 1)

The arrangement according to claim 1, wherein the fundamental current controller and/or the harmonic current controller receives as input the electrical rotational speed and/or an electrical angle estimated by the electrical speed estimator.

### Claim 9 (depends on 1)

The arrangement according to claim 1, further comprising:
at least one harmonic current reference calculation module configured to calculate the harmonic current reference based on at least one current reference input; and/or
a fundamental current reference calculation module configured to calculate the fundamental current reference based on at least one of the current reference input, wherein the current reference input comprises:
the operation parameter reference, in particular voltage reference, and/or
the generator output current, and/or
a DC-link voltage, and/or
an electrical frequency of the generator, and/or
an electrical angle of the generator, and/or
a torque, and/or
an acceleration and/or
a sound pressure.

### Claim 10 (depends on 1)

The arrangement according to claim 1, further comprising:
a dq-abc-transformation module configured to transform the operation parameter reference given in the fundamental dq-frame into a stator frame;
a modulator configured to derive pulse width modulation signals based on the operation parameter reference given in the stator frame and connected to supply the width modulation signals to gates of controllable switches comprised in the generator side converter portion.

### Claim 11 (depends on 1)

The arrangement according to claim 1, further comprising:
a abc-dq-transformation module configured to transform the generator output current in the stator frame into the fundamental dq-frame.

### Claim 12 (depends on 1)

An electric energy system, comprising:
a generator;
a converter comprising a generator side converter portion coupled to the generator; and
an arrangement according to claim 1.

### Claim 13 (depends on 12)

A wind turbine, comprising the electric energy system according to claim 12.

### Claim 14

A method for determining an operation parameter reference for controlling a generator side converter portion coupled to a generator, in particular of a wind turbine, the method comprising:
deriving a fundamental current error by subtracting a generator output current from a sum of a fundamental current reference and at least one harmonic current reference;
determining a fundamental operation parameter reference based on the fundamental current error;
deriving at least one harmonic current error by subtracting a filtered generator output current from the at least one harmonic current reference;
determining at least one harmonic operation parameter reference based on the at least one harmonic current error;
determining the operation parameter reference as sum of the fundamental operation parameter reference and the at least one harmonic operation parameter reference.

### Claim 15 (depends on 14)

The method for controlling a generator side converter portion coupled to a generator, comprising:
performing a method for determining an operation parameter reference according to claim 14 and
controlling the generator side converter portion coupled to a generator based on the operation parameter reference.