EP2443733A1 - Converter control - Google Patents

Converter control

Info

Publication number
EP2443733A1
EP2443733A1 EP09779756A EP09779756A EP2443733A1 EP 2443733 A1 EP2443733 A1 EP 2443733A1 EP 09779756 A EP09779756 A EP 09779756A EP 09779756 A EP09779756 A EP 09779756A EP 2443733 A1 EP2443733 A1 EP 2443733A1
Authority
EP
European Patent Office
Prior art keywords
module
voltage source
source converter
switch
multilevel voltage
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP09779756A
Other languages
German (de)
French (fr)
Inventor
Adrian Keitley
Ruchira Withanage
Robert Whitehouse
David Trainer
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
General Electric Technology GmbH
Original Assignee
Alstom Grid UK Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Alstom Grid UK Ltd filed Critical Alstom Grid UK Ltd
Publication of EP2443733A1 publication Critical patent/EP2443733A1/en
Withdrawn legal-status Critical Current

Links

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • 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
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • 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
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/483—Converters with outputs that each can have more than two voltages levels
    • H02M7/4835—Converters with outputs that each can have more than two voltages levels 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
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • 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
    • H02M1/00—Details of apparatus for conversion
    • H02M1/0003—Details of control, feedback or regulation circuits
    • H02M1/0006—Arrangements for supplying an adequate voltage to the control circuit of converters

Definitions

  • the invention relates to converter control for a multilevel voltage source converter for high voltage DC power transmission and reactive power compensation .
  • each module In multilevel voltage source converters, the current and voltage rating of each module is finite and largely determined by the capabilities of the semiconductor switching devices employed. It is common practice to achieve high power equipment by connecting a large number of modules in series, which effectively increases the total operating voltage of the converter and hence the MVA rating.
  • the series arrangement of the individual modules in the multilevel voltage source converter means that the failure of one of the modules leads to the failure of the entire multilevel voltage source converter because there is no flow path for a converter current .
  • a possible solution is the inclusion of additional, suitably packaged, high current power electronic devices such as a pair of reverse connected parallel thyristors.
  • the power electronic devices attached across the module reverts to a robust and safe bidirectional short circuit which maintains the flow of the converter current in the multilevel voltage source converter .
  • this solution maintains the operation and availability of the multilevel voltage source converter, it is however unsuitable for use in low cost power conversion equipment.
  • the inclusion of additional devices to each module can, depending on the number of modules, substantially increase the overall cost of the multilevel voltage source converter.
  • a mechanical bypass switch is provided for each module in the multilevel voltage source converter to maintain the operation and availability of the high power multilevel voltage source converter, and at a lower cost.
  • the mechanical bypass switch is connected in parallel to each module and, in the event of module failure, the mechanical bypass switch is activated to cause a short circuit so that the converter current flows through the mechanical bypass switch in both directions
  • the operation of the mechanical bypass switch is however normally irreversible due to reasons such as contact welding and loss of local power supplies. As a result, the mechanical bypass switch may need to be replaced after the mechanical bypass switch is activated to remove the short circuit.
  • a multilevel voltage source converter for high voltage DC power transmission and reactive power compensation comprising at least one power electronic module including at least one switch and an electronic bypass system, wherein the electronic bypass system is controllable to activate the or each switch in the module to cause a short circuit through the activated switch and thereby maintain a converter current through the module and the multilevel voltage source converter.
  • Utilization of the existing switches in the module is advantageous because it removes the need for additional devices, which could otherwise increase equipment costs.
  • the electronic bypass can be reversed simply by controlling the electronic bypass system to deactivate the or each switch and open the or each short circuit.
  • a mechanical bypass may be permanently latched due to contact welding and may thereby require maintenance in order to reverse the bypass .
  • the electronic bypass system may be controllable locally or remotely, and the short circuit is preferably sustained.
  • the electronic bypass system is controllable to activate the or each switch in the module to cause a short circuit during abnormal operating conditions of the module.
  • the purpose of the electronic bypass system is to implement the electronic bypass as soon as abnormal operating conditions such as control failure and equipment failure are detected.
  • the electronic bypass system may be controllable in other embodiments to activate the or each switch in the module to control the voltage of the module .
  • the module may include a local control system to receive control signals from and send alarm and status data back signals to a global control system of the multilevel voltage source converter.
  • the local control system receives control signals from the global control system, which contains instructions to operate the module, and sends alarm and status data back signals to the global control system, which include information on the status of the individual module.
  • the global control system may monitor the status of the electronic bypass system of the module via information provided in the alarm and status data back signals.
  • the alarm and status data back signals enable the global control system to be updated with the status of the electronic bypass system such as whether the electronic bypass system is currently activated or removed, which is advantageous when it comes to maintenance of the module.
  • the electronic bypass system may activate the or each switch to cause the short circuit in the event of loss of communication of control signals or data back signals between the local and global control systems
  • Losing the control signal means that the module cannot be switched in and out in the correct sequence in relation to the other modules in the converter.
  • the loss of data back signals means that there is a possibility of the module operating outside its normal operating conditions, which could lead to equipment failure such as damage from over-voltage or loss of local power supplies if the voltage falls too low.
  • the electronic bypass system therefore activates at least one switch in the module to cause the short circuit to bypass the module to maintain the converter current and thus prevents excessive charging of the module DC capacitor.
  • the or each switch may be a semiconductor switch.
  • the or each semiconductor switch may be an insulated-gate bipolar transistor.
  • a semiconductor switch is advantageous because a semiconductor switch is operable faster than a mechanical switch in performing a switching action.
  • the module may include an external or local power supply to supply power to operate the or each switch when it is activated by the electronic bypass system in order to maintain the short circuit.
  • an external power supply in the module allows the switches to be activated indefinitely and thereby allows the operation and availability of the multilevel voltage source converter to be maintained at all times.
  • the local power supply may be derived from the multilevel converter module capacitor .
  • the capacitor supplies power by discharging its stored energy when the electronic bypass is in operation.
  • the use of a capacitor means that the electronic bypass can only be maintained temporarily until the stored energy has been used.
  • the module includes a resistor connected in parallel with the capacitor.
  • the electronic bypass system may be controllable to temporarily switch off the or each activated switch so that the converter current is directed through the capacitor in order to recharge the capacitor and therefore the local power supply, which enables the electronic bypass to continue.
  • the capacitor discharges over time and will eventually run out of stored energy.
  • the activated switches are briefly switched off to recharge the capacitor and switched back on to resume the short circuit.
  • the temporary transition of the electronic bypass system from short circuit mode to recharge mode allows the multilevel voltage source converter to be run indefinitely in the event of module failure as opposed to arrangements in which the capacitor is left to discharge over time without recharging.
  • the temporary transition of the electronic bypass system from short circuit mode to recharge mode means that an extra voltage step is introduced into the output waveform during the period of capacitor recharge. This has minimal effect on the AC side power quality and harmonic distortion because in practice there are a very large number of voltage steps produced by the multilevel converter. The addition of one more step has a negligible effect and the transition to recharge mode will occur infrequently.
  • the local power supply may include a local current transformer that derives energy from the flow of the converter current.
  • a local current transformer as a power supply means that the electronic bypass will not be interrupted because the transformer continually extracts energy from the converter current, even during the electronic bypass.
  • the transformer can therefore supply power to the activated switches so as to maintain the short circuit indefinitely.
  • the local power supply may include a combination of one or more capacitors and/or one or more local current transformers .
  • the electronic bypass may be removed when normal operating conditions of the module are restored.
  • the reversibility of the electronic bypass system is advantageous because it means that the electronic bypass system is reusable and does not require any additional maintenance such as repair or replacement .
  • the multilevel voltage source converter may include a mechanical bypass switch connected in parallel with the module such that activation of the mechanical bypass switch causes current flow to pass through the mechanical bypass switch instead of the module.
  • the inclusion of the mechanical bypass switch provides a backup bypass system in the event of failure of the electronic bypass system.
  • the module may include a pair of switching devices and a capacitor connected in parallel in a half-bridge arrangement to define a 2-quadrant unipolar module, and each switching device may include a diode connected in anti-parallel with a switch.
  • the 2-quadrant unipolar module is unidirectional, i.e. it produces voltage steps in one polarity only, and can develop zero or positive voltage .
  • the module may includes two pairs of switching devices and a capacitor connected in parallel in a full-bridge arrangement to define a 4-quadrant bipolar module, and each switching device may include a diode connected in anti-parallel with a switch.
  • the 4-quadrant bipolar module is bidirectional, i.e. it produces voltage steps in both positive and negative polarities, and can develop a zero, positive or negative voltage.
  • the multilevel voltage source converter may include a plurality of modules arranged in series.
  • the series arrangement of the individual modules forms a single phase multilevel converter.
  • the single phase multilevel voltage source converter can have unidirectional or bidirectional characteristics depending on the type of switching arrangement in the modules.
  • Figure 1 shows a module which forms one element of a multilevel converter
  • Figure 2a shows a module operating in electronic bypass mode
  • Figure 2b shows a module operating in capacitor recharge mode
  • Figure 3a shows a multilevel voltage source converter according to a first embodiment of the invention.
  • Figure 3b shows a multilevel voltage source converter according to a second embodiment of the invention .
  • a multilevel voltage source converter 11 according to a first embodiment of the invention is shown in Figure 1.
  • the multilevel voltage source converter 11 includes a module 40 including at least one switch 12 and an electronic bypass system, wherein the electronic bypass system is controllable to activate the or each lower switch 12 in the module 40 to cause a short circuit through the activated lower switch 12 and thereby maintain a converter current through the module 40 and the multilevel voltage source converter 13.
  • the electronic bypass system is controllable to activate the or each lower switch 12 in the module 40 to cause a short circuit during abnormal operating conditions of the module 40.
  • Abnormal operating conditions may include failure of certain components in the module or control failure.
  • the module 40 includes a local control system 14 which receives control signals 16 from and sends alarm and status data back signals 18 to a global control system 20 of the multilevel voltage source converter 13, which include information on the status of the individual module.
  • the global control system 20 monitors the status of the electronic bypass system of the module 40 via the information provided in the alarm and status data back signals 18.
  • the alarm and status data back signals 18 enable the global control system 20 to be updated with the status of the electronic bypass system, such as whether the electronic bypass system is currently activated or removed.
  • the electronic bypass system activates the or each switch 12 to cause the short circuit in the event that the communication of control signals 16 or data back signals 18 between the local control system 14 and global control systems 20 is lost.
  • control signals 16 or data back signals 18 signifies control failure, and therefore the electronic bypass system activates the or each switch 12 to short circuit the module.
  • the switch 12 is provided in the form of an insulated-gate bipolar transistor .
  • the module 40 includes a local power supply 22 which supplies power to the or each switch 12 that is activated by the electronic bypass system in order to maintain the short circuit.
  • the local power supply draws energy from a module DC capacitor 24.
  • electronic bypass as shown in
  • the capacitor 24 is recharged by temporarily switching off the or each activated switch 12 so that the converter current 36 is directed through the capacitor 24, as shown in Figure 2b.
  • the electronic bypass system When the module capacitor has sufficiently recharged, the electronic bypass system reactivates the switches 12 to resume the short circuit.
  • the temporary transition of the electronic bypass system from short circuit mode to recharge mode allows the capacitor 24 to recharge itself and to continue to feed the local power supply for the activated switches 12.
  • the module 40 includes a resistor 26 connected in parallel with the capacitor 24.
  • the local power supply 22 may include a local current transformer which is continuously charged by the converter current, even during the short circuiting of the module 40.
  • the local power supply may include a combination of any one of the local power supply 22, the capacitor 24 or the local current transformer to utilise their respective advantages.
  • the local power supply may be replaced by an external power supply.
  • the electronic bypass is removed when normal operating conditions of the module 40 are restored.
  • the module 40 includes a mechanical bypass switch 28 connected in parallel with the module, and the activation of the mechanical bypass switch 28 causes the current flow to pass through the mechanical bypass switch 28 instead of the module 40.
  • the mechanical bypass switch 28 serves as a backup to the electronic bypass system in the event that the electronic bypass system fails.
  • the module 40 may be provided in the form of a 2-quadrant unipolar module 42, such as that shown in Figure 3a.
  • Figure 3a includes a pair of switching devices 10 and a capacitor 24 connected in parallel in a half-bridge arrangement.
  • Each switching device includes a diode 30 connected in anti-parallel with a switch 12.
  • the module 42 can develop zero or positive voltage and allows the voltage source converter 11 to produce voltage steps in one polarity only.
  • the module 40 may be provided in the form of a 4-quadrant bipolar module 44, such as that shown in Figure 3b.
  • the 4-quadrant bipolar module 44 shown in Figure 3b includes two pairs of switching devices 10 and a capacitor 24 connected in parallel in a full- bridge arrangement.
  • the or each switching device includes a diode 30 connected in anti-parallel with a switch 10.
  • the module 44 can develop positive or negative voltage and allows the voltage source converter 11 to produce voltage steps in both positive and negative polarities.
  • the multilevel voltage source converter 13 may include a plurality of modules 40 arranged in series.
  • the series arrangement of the individual modules 40 forms a single phase multilevel voltage source converter 13.
  • the single phase multilevel converter can have unidirectional or bidirectional characteristics depending on whether the modules 40 are 2-quadrant unipolar modules 42 or 4- quadrant bipolar modules 44.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

A multilevel voltage source converter (11) for high voltage DC power transmission and reactive power compensation comprises at least one module (40) including at least one switch (12) and an electronic bypass system. The electronic bypass system is controllable to activate the at least one switch (12) in the module (40) to cause a short circuit through the activated switch (12) and thereby maintain a converter current (36) through the module (40) and the multilevel voltage source converter (11).

Description

CONVERTER CONTROL
The invention relates to converter control for a multilevel voltage source converter for high voltage DC power transmission and reactive power compensation .
In multilevel voltage source converters, the current and voltage rating of each module is finite and largely determined by the capabilities of the semiconductor switching devices employed. It is common practice to achieve high power equipment by connecting a large number of modules in series, which effectively increases the total operating voltage of the converter and hence the MVA rating. The series arrangement of the individual modules in the multilevel voltage source converter means that the failure of one of the modules leads to the failure of the entire multilevel voltage source converter because there is no flow path for a converter current .
It is therefore desirable to provide a bypass system for each module of the multilevel voltage source converter, which acts independently of the other modules in the multilevel voltage source converter to maintain the operation and availability of the multilevel voltage source converter at all times.
A possible solution is the inclusion of additional, suitably packaged, high current power electronic devices such as a pair of reverse connected parallel thyristors. In the event of equipment failure in a module, the power electronic devices attached across the module reverts to a robust and safe bidirectional short circuit which maintains the flow of the converter current in the multilevel voltage source converter . Whilst this solution maintains the operation and availability of the multilevel voltage source converter, it is however unsuitable for use in low cost power conversion equipment. The inclusion of additional devices to each module can, depending on the number of modules, substantially increase the overall cost of the multilevel voltage source converter.
Conventionally, a mechanical bypass switch is provided for each module in the multilevel voltage source converter to maintain the operation and availability of the high power multilevel voltage source converter, and at a lower cost. The mechanical bypass switch is connected in parallel to each module and, in the event of module failure, the mechanical bypass switch is activated to cause a short circuit so that the converter current flows through the mechanical bypass switch in both directions
The operation of the mechanical bypass switch is however normally irreversible due to reasons such as contact welding and loss of local power supplies. As a result, the mechanical bypass switch may need to be replaced after the mechanical bypass switch is activated to remove the short circuit.
These factors can lead to costly and time- consuming maintenance of the converter. However, for many failure modes, the module semiconductor switches may remain locally controllable. According to an aspect of the invention there is provided a multilevel voltage source converter for high voltage DC power transmission and reactive power compensation comprising at least one power electronic module including at least one switch and an electronic bypass system, wherein the electronic bypass system is controllable to activate the or each switch in the module to cause a short circuit through the activated switch and thereby maintain a converter current through the module and the multilevel voltage source converter.
Utilization of the existing switches in the module is advantageous because it removes the need for additional devices, which could otherwise increase equipment costs.
The electronic bypass can be reversed simply by controlling the electronic bypass system to deactivate the or each switch and open the or each short circuit. In comparison, a mechanical bypass may be permanently latched due to contact welding and may thereby require maintenance in order to reverse the bypass .
The electronic bypass system may be controllable locally or remotely, and the short circuit is preferably sustained.
Preferably the electronic bypass system is controllable to activate the or each switch in the module to cause a short circuit during abnormal operating conditions of the module. The purpose of the electronic bypass system is to implement the electronic bypass as soon as abnormal operating conditions such as control failure and equipment failure are detected. The electronic bypass system may be controllable in other embodiments to activate the or each switch in the module to control the voltage of the module .
In embodiments of the invention the module may include a local control system to receive control signals from and send alarm and status data back signals to a global control system of the multilevel voltage source converter.
The local control system receives control signals from the global control system, which contains instructions to operate the module, and sends alarm and status data back signals to the global control system, which include information on the status of the individual module. In such embodiments, the global control system may monitor the status of the electronic bypass system of the module via information provided in the alarm and status data back signals.
The alarm and status data back signals enable the global control system to be updated with the status of the electronic bypass system such as whether the electronic bypass system is currently activated or removed, which is advantageous when it comes to maintenance of the module. The electronic bypass system may activate the or each switch to cause the short circuit in the event of loss of communication of control signals or data back signals between the local and global control systems
Losing the control signal means that the module cannot be switched in and out in the correct sequence in relation to the other modules in the converter. The loss of data back signals means that there is a possibility of the module operating outside its normal operating conditions, which could lead to equipment failure such as damage from over-voltage or loss of local power supplies if the voltage falls too low. In such circumstances the electronic bypass system therefore activates at least one switch in the module to cause the short circuit to bypass the module to maintain the converter current and thus prevents excessive charging of the module DC capacitor.
In embodiments of the invention the or each switch may be a semiconductor switch. In one such embodiment, the or each semiconductor switch may be an insulated-gate bipolar transistor.
The use of a semiconductor switch is advantageous because a semiconductor switch is operable faster than a mechanical switch in performing a switching action.
In embodiments of the invention the module may include an external or local power supply to supply power to operate the or each switch when it is activated by the electronic bypass system in order to maintain the short circuit. The inclusion of an external power supply in the module allows the switches to be activated indefinitely and thereby allows the operation and availability of the multilevel voltage source converter to be maintained at all times.
In other embodiments the local power supply may be derived from the multilevel converter module capacitor .
The capacitor supplies power by discharging its stored energy when the electronic bypass is in operation. The use of a capacitor means that the electronic bypass can only be maintained temporarily until the stored energy has been used.
Preferably the module includes a resistor connected in parallel with the capacitor.
The electronic bypass system may be controllable to temporarily switch off the or each activated switch so that the converter current is directed through the capacitor in order to recharge the capacitor and therefore the local power supply, which enables the electronic bypass to continue.
The capacitor discharges over time and will eventually run out of stored energy. In order to maintain the operation of the multilevel voltage source converter, the activated switches are briefly switched off to recharge the capacitor and switched back on to resume the short circuit. The temporary transition of the electronic bypass system from short circuit mode to recharge mode allows the multilevel voltage source converter to be run indefinitely in the event of module failure as opposed to arrangements in which the capacitor is left to discharge over time without recharging.
The temporary transition of the electronic bypass system from short circuit mode to recharge mode means that an extra voltage step is introduced into the output waveform during the period of capacitor recharge. This has minimal effect on the AC side power quality and harmonic distortion because in practice there are a very large number of voltage steps produced by the multilevel converter. The addition of one more step has a negligible effect and the transition to recharge mode will occur infrequently.
In other embodiments the local power supply may include a local current transformer that derives energy from the flow of the converter current.
The use of a local current transformer as a power supply means that the electronic bypass will not be interrupted because the transformer continually extracts energy from the converter current, even during the electronic bypass. The transformer can therefore supply power to the activated switches so as to maintain the short circuit indefinitely.
In further embodiments the local power supply may include a combination of one or more capacitors and/or one or more local current transformers .
The respective advantages of the different power supplies is utilised by using various combinations of these various components for the electronic bypass system. In embodiments of the invention the electronic bypass may be removed when normal operating conditions of the module are restored.
The reversibility of the electronic bypass system is advantageous because it means that the electronic bypass system is reusable and does not require any additional maintenance such as repair or replacement .
In further embodiments the multilevel voltage source converter may include a mechanical bypass switch connected in parallel with the module such that activation of the mechanical bypass switch causes current flow to pass through the mechanical bypass switch instead of the module. The inclusion of the mechanical bypass switch provides a backup bypass system in the event of failure of the electronic bypass system.
In embodiments of the invention the module may include a pair of switching devices and a capacitor connected in parallel in a half-bridge arrangement to define a 2-quadrant unipolar module, and each switching device may include a diode connected in anti-parallel with a switch.
The 2-quadrant unipolar module is unidirectional, i.e. it produces voltage steps in one polarity only, and can develop zero or positive voltage .
In other embodiments the module may includes two pairs of switching devices and a capacitor connected in parallel in a full-bridge arrangement to define a 4-quadrant bipolar module, and each switching device may include a diode connected in anti-parallel with a switch.
The 4-quadrant bipolar module is bidirectional, i.e. it produces voltage steps in both positive and negative polarities, and can develop a zero, positive or negative voltage.
In embodiments of the invention the multilevel voltage source converter may include a plurality of modules arranged in series. The series arrangement of the individual modules forms a single phase multilevel converter. The single phase multilevel voltage source converter can have unidirectional or bidirectional characteristics depending on the type of switching arrangement in the modules.
Preferred embodiments of the invention will now be described, by way of non-limiting examples, with reference to the accompanying drawings in which:
Figure 1 shows a module which forms one element of a multilevel converter;
Figure 2a shows a module operating in electronic bypass mode;
Figure 2b shows a module operating in capacitor recharge mode;
Figure 3a shows a multilevel voltage source converter according to a first embodiment of the invention; and
Figure 3b shows a multilevel voltage source converter according to a second embodiment of the invention . A multilevel voltage source converter 11 according to a first embodiment of the invention is shown in Figure 1.
The multilevel voltage source converter 11 includes a module 40 including at least one switch 12 and an electronic bypass system, wherein the electronic bypass system is controllable to activate the or each lower switch 12 in the module 40 to cause a short circuit through the activated lower switch 12 and thereby maintain a converter current through the module 40 and the multilevel voltage source converter 13.
The electronic bypass system is controllable to activate the or each lower switch 12 in the module 40 to cause a short circuit during abnormal operating conditions of the module 40. Abnormal operating conditions may include failure of certain components in the module or control failure.
The module 40 includes a local control system 14 which receives control signals 16 from and sends alarm and status data back signals 18 to a global control system 20 of the multilevel voltage source converter 13, which include information on the status of the individual module. The global control system 20 monitors the status of the electronic bypass system of the module 40 via the information provided in the alarm and status data back signals 18.
The alarm and status data back signals 18 enable the global control system 20 to be updated with the status of the electronic bypass system, such as whether the electronic bypass system is currently activated or removed. The electronic bypass system activates the or each switch 12 to cause the short circuit in the event that the communication of control signals 16 or data back signals 18 between the local control system 14 and global control systems 20 is lost.
The loss of communication of control signals 16 or data back signals 18 signifies control failure, and therefore the electronic bypass system activates the or each switch 12 to short circuit the module.
It is envisaged that the switch 12 is provided in the form of an insulated-gate bipolar transistor .
The module 40 includes a local power supply 22 which supplies power to the or each switch 12 that is activated by the electronic bypass system in order to maintain the short circuit.
In the embodiment shown in Figure 1, the local power supply draws energy from a module DC capacitor 24. During electronic bypass, as shown in
Figure 2a, this arrangement causes the capacitor 24 to discharge whilst the module 40 is bypassed.
To maintain the electronic bypass, the capacitor 24 is recharged by temporarily switching off the or each activated switch 12 so that the converter current 36 is directed through the capacitor 24, as shown in Figure 2b.
When the module capacitor has sufficiently recharged, the electronic bypass system reactivates the switches 12 to resume the short circuit. The temporary transition of the electronic bypass system from short circuit mode to recharge mode allows the capacitor 24 to recharge itself and to continue to feed the local power supply for the activated switches 12.
As shown in Figure 1, the module 40 includes a resistor 26 connected in parallel with the capacitor 24.
In other embodiments, the local power supply 22 may include a local current transformer which is continuously charged by the converter current, even during the short circuiting of the module 40.
In further embodiments, the local power supply may include a combination of any one of the local power supply 22, the capacitor 24 or the local current transformer to utilise their respective advantages.
In yet further embodiments, the local power supply may be replaced by an external power supply.
The electronic bypass is removed when normal operating conditions of the module 40 are restored.
The module 40 includes a mechanical bypass switch 28 connected in parallel with the module, and the activation of the mechanical bypass switch 28 causes the current flow to pass through the mechanical bypass switch 28 instead of the module 40. The mechanical bypass switch 28 serves as a backup to the electronic bypass system in the event that the electronic bypass system fails.
The module 40 may be provided in the form of a 2-quadrant unipolar module 42, such as that shown in Figure 3a. The 2-quadrant unipolar module 42 shown in
Figure 3a includes a pair of switching devices 10 and a capacitor 24 connected in parallel in a half-bridge arrangement. Each switching device includes a diode 30 connected in anti-parallel with a switch 12.
In such embodiments, the module 42 can develop zero or positive voltage and allows the voltage source converter 11 to produce voltage steps in one polarity only. In other embodiments the module 40 may be provided in the form of a 4-quadrant bipolar module 44, such as that shown in Figure 3b.
The 4-quadrant bipolar module 44 shown in Figure 3b includes two pairs of switching devices 10 and a capacitor 24 connected in parallel in a full- bridge arrangement. The or each switching device includes a diode 30 connected in anti-parallel with a switch 10.
In such embodiments, the module 44 can develop positive or negative voltage and allows the voltage source converter 11 to produce voltage steps in both positive and negative polarities.
In further embodiments, the multilevel voltage source converter 13 may include a plurality of modules 40 arranged in series. The series arrangement of the individual modules 40 forms a single phase multilevel voltage source converter 13. The single phase multilevel converter can have unidirectional or bidirectional characteristics depending on whether the modules 40 are 2-quadrant unipolar modules 42 or 4- quadrant bipolar modules 44.

Claims

1. A multilevel voltage source converter (11) for high voltage DC power transmission and reactive power compensation comprising at least one power electronic module (40) including at least one high current switch and an electronic bypass system, wherein the electronic bypass system is controllable to activate the or each switch (12) in the module to cause a short circuit through the activated switch and thereby maintain a converter current through the module and the multilevel voltage source converter.
2. A multilevel voltage source converter according to Claim 1 wherein the electronic bypass system is controllable locally.
3. A multilevel voltage source converter according to Claim 1 wherein the electronic bypass system is controllable remotely.
4. A multilevel voltage source converter according to any preceding claim wherein the electronic bypass system is controllable to activate the or each switch in the module to cause a short circuit during abnormal operating conditions of the module.
5. A multilevel voltage source converter according to any of Claims 1 to 3 wherein the electronic bypass system is controllable to activate the or each switch in the module to control the voltage of the module.
6. A multilevel voltage source converter according to any of Claims 1 to 4 wherein the module
(40) includes a local control system (14) to receive control signals (16) from and send alarm and status data back signals (18) to a global control system (20) of the multilevel voltage source converter.
7. A multilevel voltage source converter according to Claim 6 wherein the global control system (20) monitors the status of the electronic bypass system of the module via information provided in the alarm and status data back signals.
8. A multilevel voltage source converter according to Claim 5 or Claim 6 wherein the electronic bypass system activates the or each switch to cause the short circuit in the event of a loss of communication of control signals or alarm and status data back signals between the local (14) and global (20) control systems .
9. A multilevel voltage source converter according to any preceding claim wherein the or each switch (12) is a semiconductor switch.
10. A multilevel voltage source converter according to Claim 8 wherein the or each semiconductor switch is an insulated-gate bipolar transistor.
11. A multilevel voltage source converter according to any preceding claim wherein the module
(40) includes a local power supply (22) to supply power to operate the or each switch (12) when it is activated by the electronic bypass system in order to maintain the short circuit.
12. A multilevel voltage source converter according to Claim 10 wherein the local power supply (22) is derived from the multilevel converter module capacitor .
13. A multilevel voltage source converter according to Claim 11 wherein the module (40) includes a resistor (26) connected in parallel with the capacitor (24) .
14. A multilevel voltage source converter according to Claim 11 or Claim 12 wherein the electronic bypass system is controllable to temporarily switch off the or each activated switch so that the converter current is directed through the capacitor (24) in order to recharge the capacitor.
15. A multilevel voltage source converter according to Claim 10 wherein the local power supply (22) includes a local current transformer that derives energy from the flow of converter current.
16. A multilevel voltage source converter according to Claim 10 wherein the local power supply (22) includes a combination of one or more capacitors and/or one or more local current transformers.
17. A multilevel voltage source converter according to any preceding claim wherein the electronic bypass is removed when normal operating conditions of the module are restored.
18. A multilevel voltage source converter according to any of the preceding claims wherein the multilevel voltage source converter (11) includes a mechanical bypass switch (28) connected in parallel with the module (40) such that activation of the mechanical bypass switch causes current flow to pass through the mechanical bypass switch instead of the module .
19. A multilevel voltage source converter according to any preceding claim wherein the module (40) includes a pair of switching devices (10) and a capacitor (24) connected in parallel in a half-bridge arrangement to define a 2-quadrant unipolar module (42) , and each switching device includes a diode (30) connected in anti-parallel with a switch (12) .
20. A multilevel voltage source converter according to any of Claims 1 to 18 wherein the module includes two pairs of switching devices (10) and a capacitor (24) connected in parallel in a full-bridge arrangement to define a 4-quadrant bipolar module (44), and each switching device includes a diode (30) connected in anti-parallel with a switch (12) .
21. A multilevel voltage source converter according to any preceding claim wherein the multilevel voltage source converter includes a plurality of modules arranged in series.
EP09779756A 2009-06-15 2009-06-15 Converter control Withdrawn EP2443733A1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
PCT/EP2009/057381 WO2010145688A1 (en) 2009-06-15 2009-06-15 Converter control

Publications (1)

Publication Number Publication Date
EP2443733A1 true EP2443733A1 (en) 2012-04-25

Family

ID=41796482

Family Applications (1)

Application Number Title Priority Date Filing Date
EP09779756A Withdrawn EP2443733A1 (en) 2009-06-15 2009-06-15 Converter control

Country Status (2)

Country Link
EP (1) EP2443733A1 (en)
WO (1) WO2010145688A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2510769C1 (en) * 2012-11-14 2014-04-10 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Уфимский государственный нефтяной технический университет" Multilevel frequency converter with differential voltage levels and bypass semiconductor keys

Families Citing this family (31)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN102804571B (en) 2009-06-15 2015-05-13 阿尔斯通技术有限公司 Converter
KR101670309B1 (en) 2009-06-22 2016-10-28 제네럴 일렉트릭 테크놀러지 게엠베하 Converter
US9350269B2 (en) 2009-07-31 2016-05-24 Alstom Technology Ltd. Configurable hybrid converter circuit
US8861231B2 (en) 2010-02-09 2014-10-14 Alstom Technology Ltd Converter
CA2791082A1 (en) 2010-03-15 2011-09-22 Alstom Technology Ltd Static var compensator with multilevel converter
DK2556585T3 (en) 2010-04-08 2014-05-05 Alstom Technology Ltd Hybrid high voltage DC converter
CA2795315C (en) 2010-04-15 2017-08-15 Alstom Technology Ltd Hybrid 2-level and multilevel hvdc converter
CN103026603B (en) 2010-06-18 2016-04-13 阿尔斯通技术有限公司 For the transducer of HVDC transmission and reactive power compensation
BR112013001600A2 (en) 2010-07-30 2016-05-17 Alstom Technology Ltd '' electronic power converter ''
EP2601562A4 (en) * 2010-08-04 2016-01-27 Benshaw Inc M2lc system coupled to a current source power supply
CA2833450A1 (en) 2011-06-08 2012-12-13 Alstom Technology Ltd High voltage dc/dc converter with cascaded resonant tanks
CA2840345C (en) * 2011-06-29 2016-06-07 Abb Technology Ag Method and controller for protecting a voltage source converter
CN103891121B (en) 2011-08-01 2016-11-23 阿尔斯通技术有限公司 DC-to-DC converter assembly
WO2013068031A1 (en) 2011-11-07 2013-05-16 Alstom Technology Ltd Control circuit
US9362848B2 (en) 2011-11-17 2016-06-07 Alstom Technology Ltd. Hybrid AC/DC converter for HVDC applications
CN103124071A (en) * 2011-11-18 2013-05-29 北京赤那思电气技术有限公司 On-line monitoring allowable intelligent high voltage reactive power compensation device
WO2013083414A2 (en) * 2011-12-05 2013-06-13 Abb Technology Ag Method for eliminating an electric arc driven by at least one voltage source of an inverter circuit
CN104160572B (en) 2012-03-01 2017-03-01 阿尔斯通技术有限公司 Control circuit
CN102684468B (en) * 2012-05-18 2014-10-15 卧龙电气集团股份有限公司 Bypass cross control circuit and control method of high-voltage frequency conversion device
US9876347B2 (en) 2012-08-30 2018-01-23 Siemens Aktiengesellschaft Apparatus and methods for restoring power cell functionality in multi-cell power supplies
WO2014053156A1 (en) 2012-10-01 2014-04-10 Abb Technology Ltd Converter arm and associated converter device
WO2014148100A1 (en) * 2013-03-18 2014-09-25 三菱電機株式会社 Power conversion apparatus
WO2014169958A1 (en) * 2013-04-18 2014-10-23 Abb Technology Ltd Mechanical bypass switch device, converter arm and power converter
JP5889498B2 (en) * 2014-03-05 2016-03-22 三菱電機株式会社 Power converter
WO2016002319A1 (en) * 2014-06-30 2016-01-07 三菱電機株式会社 Power conversion device
DK3309949T3 (en) * 2015-06-15 2020-03-23 Toshiba Mitsubishi Elec Ind power conversion
WO2018193606A1 (en) * 2017-04-21 2018-10-25 東芝三菱電機産業システム株式会社 Power conversion device
WO2020043273A1 (en) * 2018-08-28 2020-03-05 Siemens Aktiengesellschaft Assembly comprising a module of a multi-level converter
EP3934089A1 (en) * 2020-06-29 2022-01-05 Maschinenfabrik Reinhausen GmbH Cell assembly and converter comprising a plurality of arms, each having such a cell assembly
WO2023072398A1 (en) * 2021-10-28 2023-05-04 Hitachi Energy Switzerland Ag A high voltage direct current, hvdc, converter and a method for handling a fault in such converter
KR20230149455A (en) * 2022-04-20 2023-10-27 엘에스일렉트릭(주) Submodule device and modular multi-level converter

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59198869A (en) * 1983-04-26 1984-11-10 Fuji Electric Co Ltd Thyristor switch firing device
JPH0658960A (en) 1992-08-04 1994-03-04 Central Res Inst Of Electric Power Ind Power line measuring apparatus
US6496391B1 (en) 2001-08-07 2002-12-17 Mitsubishi Denki Kabushiki Kaisha Power supply unit utilizing a current transformer
US20080232145A1 (en) * 2005-08-26 2008-09-25 Siemens Aktiengesellschaft Inverter Circuit with Distributed Energy Stores

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE102005041087A1 (en) * 2005-08-30 2007-03-01 Siemens Ag Static inverter circuit has interconnect points formed between semiconductor switches for connection terminals of two-pole subsystem and connection to reference potential connection of electronics
US8008923B2 (en) * 2006-09-28 2011-08-30 Siemens Industry, Inc. Method for bypassing a power cell of a power supply

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59198869A (en) * 1983-04-26 1984-11-10 Fuji Electric Co Ltd Thyristor switch firing device
JPH0658960A (en) 1992-08-04 1994-03-04 Central Res Inst Of Electric Power Ind Power line measuring apparatus
US6496391B1 (en) 2001-08-07 2002-12-17 Mitsubishi Denki Kabushiki Kaisha Power supply unit utilizing a current transformer
US20080232145A1 (en) * 2005-08-26 2008-09-25 Siemens Aktiengesellschaft Inverter Circuit with Distributed Energy Stores

Non-Patent Citations (6)

* Cited by examiner, † Cited by third party
Title
British Standard BS EN 60831-1:1998/IEC 60831-1:1996
GUANJUN DING ET AL: "New technologies of voltage source converter (VSC) for HVDC transmission system based on VSC", POWER AND ENERGY SOCIETY GENERAL MEETING - CONVERSION AND DELIVERY OF ELECTRICAL ENERGY IN THE 21ST CENTURY, 2008 IEEE, IEEE, PISCATAWAY, NJ, USA, 20 July 2008 (2008-07-20), pages 1 - 8, XP031304187, ISBN: 978-1-4244-1905-0 *
International Standard IEC 60110-1, first edition, 1998-06
LESNICAR ET AL: "A new modular voltage source inverter topology", 20030101; 20030000, 1 January 2003 (2003-01-01), XP002447361 *
MARQUARDT ET AL: "New Concept for High Voltage - Modular Multilevel Converter", POWER ELECTRONICS SPECIALISTS CONFERENCE, 2004. PESC 04. 2004 IEEE 35TH ANNUAL, AACHEN, GERMANY 20-25 JUNE 2004, PISCATAWAY, NJ, USA,IEEE, US, 1 January 2004 (2004-01-01), XP002447362, ISBN: 978-0-7803-8399-9 *
See also references of WO2010145688A1

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
RU2510769C1 (en) * 2012-11-14 2014-04-10 Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Уфимский государственный нефтяной технический университет" Multilevel frequency converter with differential voltage levels and bypass semiconductor keys

Also Published As

Publication number Publication date
WO2010145688A1 (en) 2010-12-23

Similar Documents

Publication Publication Date Title
EP2443733A1 (en) Converter control
KR102005104B1 (en) Control circuit
JP6417043B2 (en) Power converter
EP2987229B1 (en) Mechanical bypass switch device, converter arm and power converter
CN101611535B (en) Method for limiting damage to a converter having a power semiconductor in the case of a short circuit of an intermediate direct current circuit
JP5300988B2 (en) Series circuit of on-off controllers for transferring energy in battery systems
CA2782502C (en) Battery energy storage system with short circuit protection, and method
US11742669B2 (en) Wind turbine with integrated battery storage
KR102234290B1 (en) Energy storage system and controlling method the same
US8847664B2 (en) Gate control circuit, power module and associated method
KR20130056833A (en) Method for operating a converter and a switching cell and a converter
US9479011B2 (en) Method and system for a dual conversion uninterruptible power supply
US9787173B2 (en) Multilevel converter
KR102467712B1 (en) Power supply system and method
KR101809913B1 (en) energy storage system type modular converter controlling system, and controlling method thereof
US20200099249A1 (en) Optimized structure of a dc voltage system and method in the event of failure of the supplying network
US20220311354A1 (en) Intelligent discharge control for modular multilevel converter
US20210044215A1 (en) Power conversion apparatus
US8369050B2 (en) Circuit for protecting a DC network with DC loads against overvoltage
JP4759535B2 (en) Uninterruptible power system
RU2766312C1 (en) Self-diagnosing system of providing uninterrupted power supply of on-board equipment
JP2011109842A (en) Circuit and topology for ultra-high reliability power electronics system
JP2004064996A (en) Power supply device
CN112868179A (en) Electronic valve device
CN112514226A (en) Inverter with intermediate circuit protection

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 20120102

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO SE SI SK TR

TPAC Observations filed by third parties

Free format text: ORIGINAL CODE: EPIDOSNTIPA

DAX Request for extension of the european patent (deleted)
RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: ALSTOM TECHNOLOGY LTD

RAP1 Party data changed (applicant data changed or rights of an application transferred)

Owner name: GENERAL ELECTRIC TECHNOLOGY GMBH

17Q First examination report despatched

Effective date: 20160525

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Effective date: 20171207