A control apparatus for a power converter

Patent metadata

Field	Value
Publication number	US-2016308453-A1
Application number	US-201415100620-A
Country	US
Kind code	A1
Filing date	Dec 4, 2014
Priority date	Dec 6, 2013
Publication date	Oct 20, 2016
Grant date	—

Abstract

A control apparatus configured to control a chain link voltage source converter, the control apparatus comprising; two converter controllers, each converter controller configured to receive a measure of the output voltage and/or current from the converter and determine a control signal therefrom for controlling the voltage source converter, each converter controller including at least one integrator element configured to perform an integration operation and output an integrator term in said determination of the control signal, a selector configured to select which one of the converter controllers provides its control signal to the converter; wherein each integrator element is configured to have two modes, a first mode in which the integrator element determines the integrator term and a second mode in which the integrator term is provided by a corresponding integrator element in the other converter controller.

First claim

1 . A control apparatus for controlling a voltage source converter, the control apparatus comprising;
two converter controllers, each converter controller configured to receive a measure of the output voltage and/or current from the converter and determine a control signal therefrom for controlling the converter, each converter controller including at least one integrator element configured to perform an integration operation and output an integrator term in said determination of the control signal, a selector configured to select which one of the converter controllers provides its control signal to the converter; wherein the or each integrator element is configured to have two modes, a first mode in which the integrator element determines the integrator term and a second mode in which the integrator term is provided by a corresponding integrator element in the other converter controller.

2 . A control apparatus according to claim 1 , in which each controller contains a plurality of integrator elements configured to perform an integration operation and output an integrator term for use in said determination of the control signal, wherein a subset of said integrator elements have said two modes of operation and the remaining integrator element(s) are configured to be initialised with a predetermined integrator term.

3 . A control apparatus according to claim 2 , in which said integrator term(s) represents an error value comprising a deviation from a set-point and said predetermined integrator term represents a zero error.

4 . A control apparatus according to claim 1 in which the control apparatus is configured to provide the integrator term of the integration element in one of the controllers for initialising the integrator element of the other controller at least when switching between the controllers.

5 . A control apparatus according to claim 1 , in which the apparatus is configured such that on selection of one of the converter controllers by the selector to provide the control signal to the converter, its integrator element(s) is switched to the first mode from the second mode such that said integrator element(s) initiates its determination of its integrator term using the integrator term provided by the corresponding integrator element in the other converter controller.

6 . A control apparatus according to claim 1 , in which the apparatus is configured such that on de-selection of one of the controllers by the selector, the integrator element(s) of said deselected controller is switched to the second mode.

7 . A control apparatus according to claim 1 , in which the selector is configured to switch the integrator element(s) between the two modes.

8 . A control apparatus according to claim 2 , in which said subset of integrator elements comprises one or more of the following;
i) an integrator element configured to provide a DC voltage control integrator term for DC voltage control in a DC outer loop control element; ii) an integrator element configured to provide a DC power control integrator term for DC voltage control in a DC outer loop control element; iii) an integrator element configured to provide a AC quadrature term for quadrature control in an AC vector control element; iv) an integrator element configured to provide a direct positive sequence term for use in an AC vector control element; v) an integrator element configured to provide a quadrature positive sequence term for use in an AC vector control element; vi) an integrator element configured to provide a direct negative sequence term for use in an AC vector control element; and vii) an integrator element configured to provide a quadrature negative sequence term for use in an AC vector control element.

9 . A control apparatus according to claim 2 , in which said remaining integrator elements, configured to be initialised with a predetermined value, comprise one or more of the following;
i) an integrator element configured to provide a zero sequence term for use in an AC vector control element; ii) an integrator element configured to provide a quadrature zero sequence term for use in an AC vector control element; iii) integrator elements configured to provide a capacitor balancing term for use in calculating a capacitor balancing compensation signal in a capacitor balancing control element; iv) integrator elements configured to provide a differential capacitor balancing term for use in calculating a capacitor balancing compensation signal between subsets of capacitors in the converter in a capacitor balancing control element.

10 . A control apparatus according to claim 1 , in which the control apparatus includes a fault monitoring device for identifying a fault in the controller that supplies the control signal to the converter, the fault monitoring device configured to actuate the selector on identification of a fault to select the other controller.

11 . A control apparatus according to claim 1 , in which the integrator element(s) form part of a proportional-integral (PI) controller or proportional-integral-derivative (PID) controller.

12 . A control apparatus according to claim 1 , in which each controller includes a measurement device for measuring the output of the converter.

13 . A control apparatus according to claim 1 , in which each controller includes a DC outer loop element for controlling DC power flow, an AC vector control element for determining an AC voltage demand signal and a module selection element for providing a switching signal to the voltage source converter, said integrator element(s) forming part of at least one of said DC outer loop element and AC vector control element.

14 . A control apparatus according to claim 13 , in which the selector is configured to connect the output of the module selection element of one of the controllers to the voltage source converter and disconnect the output of the other module selection element of the other controller.

15 . A control apparatus according to claim 1 , in which the first and second mode of the or each integrator element is controlled by an integrator output control comprising a switch configured to switch between the output of the integrator element with which it is associated and the output of the corresponding integrator element in the other controller.

16 . A voltage source converter of chain link type the voltage source converter comprising:
a control apparatus for controlling the voltage source converter, the control apparatus comprising;
two converter controllers, each converter controller configured to receive a measure of the output voltage and/or current from the converter and determine a control signal therefrom for controlling the converter, each converter controller including at least one integrator element configured to perform an integration operation and output an integrator term in said determination of the control signal,
a selector configured to select which one of the converter controllers provides its control signal to the converter; and
wherein the or each integrator element is configured to have two modes, a first mode in which the integrator element determines the integrator term and a second mode in which the integrator term is provided by a corresponding integrator element in the other converter controller.

17 . A power transmission network, the power transmission network comprising:
a voltage source converter of chain length type, the voltage source converter comprising:
a control apparatus for controlling a voltage source converter, the control apparatus comprising;
two converter con

Assignees

• General Electric Technology Gmbh

Inventors

• Oates Colin Donald Murray

Classifications

• H02M1/08

  Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters · CPC title

• H02M5/44 Primary

  using discharge tubes or semiconductor devices to convert the intermediate DC into AC · CPC title

• H02M7/4835

  comprising two or more cells, each including a switchable capacitor, the capacitors having a nominal charge voltage which corresponds to a given fraction of the input voltage, and the capacitors being selectively connected in series to determine the instantaneous output voltage · CPC title

• H02M7/4833 Primary

  Capacitor voltage balancing · CPC title

• H02M7/219 Primary

  in a bridge configuration · CPC title