CN112821739A - Converter arm, series high-voltage direct-current transformer and control method - Google Patents
Converter arm, series high-voltage direct-current transformer and control method Download PDFInfo
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- CN112821739A CN112821739A CN201911130085.4A CN201911130085A CN112821739A CN 112821739 A CN112821739 A CN 112821739A CN 201911130085 A CN201911130085 A CN 201911130085A CN 112821739 A CN112821739 A CN 112821739A
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- 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
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- 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
- H02M3/00—Conversion of dc power input into dc power output
- H02M3/22—Conversion of dc power input into dc power output with intermediate conversion into ac
- H02M3/24—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters
- H02M3/28—Conversion of dc power input into dc power output with intermediate conversion into ac by static converters using discharge tubes with control electrode or semiconductor devices with control electrode to produce the intermediate ac
Abstract
The application provides a converter arm, a series high-voltage direct-current transformer and a control method. The head end of the current conversion arm is connected with a direct current anode, the tail end of the current conversion arm is connected with a direct current cathode, the midpoint of the current conversion arm is led out to be used as an alternating current end of the current conversion arm, and the current conversion arm comprises at least one energy consumption unit and at least one voltage sharing unit; the voltage equalizing unit comprises a first direct current capacitor, a first power semiconductor device, a third power semiconductor device and a fourth power semiconductor device which are connected in series, and the other end of the third power semiconductor device is connected with a connection point or an energy consumption unit of the third power semiconductor device and the fourth power semiconductor device of the adjacent voltage equalizing unit; one end of the first direct current capacitor is connected with a connection point of the third power semiconductor device and the fourth power semiconductor device, one end of the first power semiconductor device is connected with the other end of the first direct current capacitor, the other end of the first power semiconductor device is connected with the other end of the fourth power semiconductor device, and the first power semiconductor devices of all the voltage equalizing units are sequentially connected in series in the same direction.
Description
Technical Field
The application relates to the technical field of power electronics, in particular to a converter arm, a series high-voltage direct-current transformer and a control method.
Background
High voltage direct current transformers are generally used in the field of direct current transmission or direct current distribution for connecting direct current ports of different voltage classes.
With the development of modern power electronic technology, the application and development of single-tube power semiconductor devices are greatly limited due to the relatively limited voltage-resistant grade of the single-tube power semiconductor devices.
The power semiconductor devices form sub-modules, then the sub-modules are cascaded to form a converter arm, and the converter arm can form an isolated direct current transformer and a non-isolated direct current transformer in different combination modes. Therefore, the converter arm is a key component unit playing a role in power conversion no matter an isolated or non-isolated direct current transformer. In the application of the direct-current transformer, once a converter arm bears overvoltage or a single submodule bears overvoltage, a device can be damaged, and the whole converter arm can be damaged due to failure after the failure is expanded.
In the prior art, devices are additionally connected between modules, for example, in patent CN105406722A, a diode-clamped power switch is connected in series with a high-voltage dc transformer, the method of the above-mentioned reference document is to establish a charge-discharge channel between direct-current capacitors of submodules by using diodes, and to form a closed loop between the submodules between bridge arms by using an auxiliary circuit, so as to achieve the function of balancing direct-current voltage, but the total energy of the converter cannot be consumed, and only flows between the submodules of the converter. The defects of the mode are as follows: firstly, energy caused by overvoltage cannot be consumed, only the energy can be transferred among modules, and when the overvoltage is serious, the total energy cannot be consumed, and equipment can still be damaged; secondly, once a middle link of the whole closed loop fails, the whole closed loop system is disconnected, energy can be accumulated in the sub-module at the disconnection position of the converter arm, the sub-module is damaged by overvoltage, and reliability is low.
Because the short-time overvoltage problem under the fault condition cannot be solved, in order to enable the whole current conversion arm to bear higher short-time overvoltage, the capacitance value of the capacitor in the sub-modules can only be increased, or the number of the sub-modules is increased, and the cost and the occupied area of the whole current conversion arm are greatly increased.
Disclosure of Invention
The embodiment of the application provides a current conversion arm, wherein the head end of the current conversion arm is connected with a direct current positive electrode, the tail end of the current conversion arm is connected with a direct current negative electrode, the midpoint of the current conversion arm is led out to serve as an alternating current end of the current conversion arm, the current conversion arm comprises M voltage-sharing units and R energy-consuming units which are connected in series, and M and R are integers greater than or equal to 1; the voltage equalizing unit comprises a first direct current capacitor, a first power semiconductor device, a third power semiconductor device and a fourth power semiconductor device which are connected in series, and the other end of the third power semiconductor device is connected with a connecting point or an energy consumption unit of the third power semiconductor device and the fourth power semiconductor device of the adjacent voltage equalizing unit; one end of the first direct current capacitor is connected with a connection point of the third power semiconductor device and the fourth power semiconductor device, one end of the first power semiconductor device is connected with the other end of the first direct current capacitor, the other end of the first power semiconductor device is connected with the other end of the fourth power semiconductor device, and the first power semiconductor devices of all the voltage equalizing units are sequentially connected in series in the same direction.
According to some embodiments, the first power semiconductor device comprises: a fully-controlled power semiconductor device.
According to some embodiments, the third and fourth power semiconductor devices each comprise: at least one of a diode or a fully controlled power semiconductor device.
According to some embodiments, the energy consuming unit comprises a first switch, a first resistor, a second direct current capacitor and a second power semiconductor device, wherein the first switch comprises a solid state switch or a mechanical switch formed by the power semiconductor devices; the first resistor is connected in series with the first switch; a series circuit of the first switch and the first resistor is connected in parallel with the second direct current capacitor.
According to some embodiments, the energy consumption unit further comprises a second power semiconductor device, and the series circuit of the first switch and the first resistor is connected in parallel with the second dc capacitor and then connected in series with the second power semiconductor device.
According to some embodiments, the energy consumption unit further comprises a second resistor, the second resistor is connected in parallel with the second dc capacitor, and the second resistor comprises a voltage-sharing resistor or/and a non-linear resistor.
An embodiment of the present application further provides a series high-voltage dc transformer, which includes a dc-ac converter, an isolation transformer and an ac-dc converter, where the dc-ac converter includes P converter arms according to any one of claims 1 to 6, where P is an integer greater than or equal to 2, a dc positive electrode of each converter arm is connected as a dc input positive electrode of the series high-voltage dc transformer, a dc negative electrode of each converter arm is connected as a dc input negative electrode of the series high-voltage dc transformer, and an ac terminal of each converter arm is used as an ac terminal of the dc-ac converter; the primary side of the isolation transformer is connected with the alternating current end of the direct current-alternating current converter; the AC-DC converter is connected with the secondary side of the isolation transformer.
According to some embodiments, the ac-dc converter includes P converter arms, an ac end of each converter arm is connected to a secondary side of the isolation transformer, a dc positive electrode of each converter arm is connected to serve as a dc output positive electrode of the series high-voltage dc transformer, and a dc negative electrode of each converter arm is connected to serve as a dc output negative electrode of the series high-voltage dc transformer.
According to some embodiments, the ac-dc converter comprises an uncontrolled rectifier bridge or a fully controlled rectifier bridge; the uncontrolled rectifier bridge comprises a bridge circuit consisting of diodes; the full-controlled rectifier bridge comprises a full-controlled power semiconductor device or a plurality of cascaded full-bridge connected power units or half-bridge connected power units, wherein the full-bridge connected power units comprise second direct-current capacitors and full-bridge rectifier units connected in parallel with the second direct-current capacitors, and the half-bridge connected power units comprise the second direct-current capacitors and half-bridge rectifier units connected in parallel with the second direct-current capacitors.
The embodiment of the present application further provides a method for controlling the series high-voltage dc transformer, including: adjusting the output voltage of the alternating current end of the current conversion arm of the direct current-alternating current converter; and controlling the direct-current output voltage of the series high-voltage direct-current transformer to reach a given target value.
According to some embodiments, if the ac-dc converter comprises the uncontrolled rectifier bridge, said controlling the dc output voltage of the series high voltage dc transformer to a given target value comprises: and continuously adjusting the output voltage of the alternating current end until the direct current output voltage of the series high-voltage direct current transformer reaches a given target value.
According to some embodiments, if the ac-dc converter includes P converter arms or the fully controlled rectifier bridge, the controlling the dc output voltage of the series high voltage dc transformer to reach a given target value includes: and controlling the AC-DC converter to work until the DC output voltage of the series high-voltage DC transformer reaches a given target value.
The embodiment of the present application further provides a series high-voltage direct-current transformer, which includes the converter arm, the first converter chain and the second converter chain, where a dc positive electrode of the converter arm is connected to a dc input positive electrode of the series high-voltage direct-current transformer, and a dc negative electrode of the converter arm is connected to a dc input negative electrode of the series high-voltage direct-current transformer; one end of the first converter chain is connected with the alternating current end of the converter arm, the other end of the first converter chain is used as the direct current output positive electrode of the series high-voltage direct current transformer, and the direct current output negative electrode of the series high-voltage direct current transformer is connected with the direct current input negative electrode; and the second commutation chain is connected in parallel at two ends of the direct current output positive electrode and the direct current output negative electrode.
According to some embodiments, the first converter chain comprises at least N power cells in the form of a full bridge connection connected in series, N being an integer equal to or greater than 1.
According to some embodiments, the second commutation chain comprises: at least N power units in a full-bridge connection form or a half-bridge connection form are connected in series, wherein N is an integer larger than or equal to 1.
According to some embodiments, the second commutation chain comprises a commutation arm as described above, the ac end of the commutation arm not being led out.
The application also provides a control method of the series high-voltage direct-current transformer, which comprises the following steps: setting a DC input voltage reference value U of the series high voltage DC transformerinA reference value U of the DC output voltage of the series high-voltage DC transformerout(ii) a Entering a pre-charge mode; conducting an upper bridge arm of the current conversion arm; adjusting the DC output voltage of the second converter chain to UoutUntil the direct current capacitance voltage of the power unit in the first commutation chain reaches a rated value; adjusting the DC output voltage of the series high-voltage DC transformer to Uout。
According to some embodiments, the adjusting of the dc output voltage of the series high voltage dc transformer to UoutThe method comprises the following steps: switching on an upper bridge arm of the current conversion arm and switching off a lower bridge arm of the current conversion arm; adjusting the DC output voltage of the first converter chain to Uin-UoutAdjusting the DC output voltage of the series high-voltage DC transformer to be Uout(ii) a Switching on a lower bridge arm of the current conversion arm and switching off an upper bridge arm of the current conversion arm; adjusting the DC output voltage of the first converter chain to-UoutTo adjust the DC output voltage of the series high-voltage DC transformer to Uout。
According to some embodiments, the time for conducting the upper leg of the commutation arm is the same as the time for conducting the lower leg of the commutation arm.
According to the technical scheme, the converter arm is provided with the energy consumption unit, the excess energy of the submodule is transferred to the head end or the tail end of the converter arm through the diode, the excess energy is consumed by the energy consumption unit, when the system is in overvoltage, energy balance adjustment can be achieved, overvoltage is limited, the reliability of the system is greatly improved, the energy consumption unit is only arranged at the head end or the tail end of the converter arm, and the voltage-sharing and energy-consuming functions are achieved by increasing small cost.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.
Fig. 1 is a schematic diagram of a commutation arm provided in an embodiment of the present application;
FIG. 2 is a schematic diagram of another commutation arm configuration provided by an embodiment of the present application;
FIG. 3 is a schematic diagram of another commutation arm configuration provided by an embodiment of the present application;
fig. 4 is a schematic diagram of a series high-voltage dc transformer according to an embodiment of the present disclosure;
fig. 5 is a second schematic diagram of a series high-voltage dc transformer according to an embodiment of the present invention;
fig. 6 is a third schematic diagram of a series high-voltage dc transformer according to an embodiment of the present invention;
fig. 7 is a fourth schematic diagram of a series high-voltage dc transformer according to an embodiment of the present application;
fig. 8 is a schematic diagram of a power unit including a full bridge connection according to an embodiment of the present disclosure;
fig. 9 is a fifth schematic diagram of a series high-voltage dc transformer according to an embodiment of the present disclosure;
fig. 10 is a schematic diagram of a power unit including a half-bridge connection according to an embodiment of the present application;
fig. 11 is a sixth schematic diagram of a series high-voltage dc transformer according to an embodiment of the present application;
fig. 12 is a seventh schematic diagram of a series high-voltage dc transformer according to an embodiment of the present disclosure;
fig. 13 is an eighth schematic diagram of a series high-voltage dc transformer according to an embodiment of the present application.
Detailed Description
The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are some, but not all, embodiments of the present application. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.
It should be understood that the terms "first," "second," "third," "fourth," and the like in the claims, the description, and the drawings of the present application are used for distinguishing between different objects and not for describing a particular order. The term "comprises/comprising" when used in the specification and claims of this application is taken to specify the presence of stated features, integers, steps, operations, elements, and/or components, but does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
Fig. 1 is a schematic diagram of a commutation arm structure according to an embodiment of the present application.
The head end of the commutation arm 21 is connected with a direct current anode, the tail end is connected with a direct current cathode, and the midpoint of the commutation arm is led out to be used as alternating current of the commutation arm.
The commutation arms 21 comprise up to R energy consuming units 9 and M series connected voltage equalizing units 10. M voltage-sharing units 10 connected in series are connected in series with the energy consumption unit 9, and M is an integer greater than or equal to 1.
The voltage equalizing unit 10 includes a first direct current capacitor C1A first power semiconductor device T1And a third power semiconductor device D connected in series1And a fourth power semiconductor device D2. First power semiconductor devices T of M voltage equalizing units 101Are sequentially connected in series in the same direction
First direct current capacitor C1Is connected to the third power semiconductor device D1And a fourth power semiconductor device D2The connection point of (a). First power semiconductor device T1One end of the first DC capacitor C is connected with1The other end of the first power semiconductor device T1Is connected to a fourth power semiconductor device D2And the other end of the same. Third power semiconductor device D1Another end of the third power semiconductor device D is connected with the adjacent voltage equalizing unit1And a fourth power semiconductor device D2The connection points or the energy consuming units.
First power semiconductor device T1Including but not limited to fully-controlled power semiconductor devices. Third power semiconductor device D1And a fourth power semiconductor device D2Including but not limited to at least one of a diode or a fully controlled power semiconductor device.
The energy consumption unit 9 comprises a second direct current capacitor 5, a first switch 6, a first resistor 7 and a second power semiconductor device 16.
The first switch 6 includes, but is not limited to, a solid state switch or a mechanical switch formed of a power semiconductor device. The first resistor 7 is connected in series with the first switch 6. A series circuit of a first switch 6 and a first resistor 7 is connected in parallel with the second dc capacitor 5. A series circuit of the first switch 6 and the first resistor 7 is connected in parallel with the second dc capacitor 5, and then connected in series with the second power semiconductor device 16.
Optionally, the energy consumption unit 9 further includes a second resistor 13, the second resistor 13 is connected in parallel with the second dc capacitor 5, and the second resistor 13 includes, but is not limited to, a voltage-sharing resistor or/and a non-linear resistor.
As shown in fig. 1, the energy consuming unit 9 is located on top of the commutation arm 21. The energy consumption unit is connected in parallel to the two ends of the third power semiconductor device D1 and the fourth power semiconductor device D2 which are connected in series.
Fig. 2 is a schematic diagram of another commutation arm structure provided in the embodiment of the present application.
The head end of the commutation arm 21 is connected with a direct current anode, the tail end is connected with a direct current cathode, and the midpoint of the commutation arm is led out to be used as alternating current of the commutation arm.
The commutation arm 21 comprises at least one energy consuming unit 9 and M series connected voltage equalizing units 10. M voltage-sharing units 10 connected in series are connected in series with the energy consumption unit 9, and M is an integer greater than or equal to 1.
The voltage equalizing unit 10 includes a first direct current capacitor C1A first power semiconductor device T1And a third power semiconductor device D connected in series1And a fourth power semiconductor device D2. First power semiconductor devices T of M voltage equalizing units 101Are sequentially connected in series in the same direction
First direct current capacitor C1Is connected to the third power semiconductor device D1And a fourth power semiconductor device D2The connection point of (a). First power semiconductor device T1One end of the first DC capacitor C is connected with1The other end of the first power semiconductor device T1Is connected to a fourth power semiconductor device D2And the other end of the same. Third power semiconductor device D1Another end of the third power semiconductor device D is connected with the adjacent voltage equalizing unit1And a fourth power semiconductor device D2The connection points or the energy consuming units.
First power semiconductor device T1Including but not limited to fully-controlled power semiconductor devices. Third power semiconductor device D1And a fourth power semiconductor device D2Including but not limited to at least one of a diode or a fully controlled power semiconductor device.
The energy consumption unit 9 comprises a second direct current capacitor 5, a first switch 6, a first resistor 7 and a second power semiconductor device 16.
The first switch 6 includes, but is not limited to, a solid state switch or a mechanical switch formed of a power semiconductor device. The first resistor 7 is connected in series with the first switch 6. A series circuit of a first switch 6 and a first resistor 7 is connected in parallel with the second dc capacitor 5. A series circuit of the first switch 6 and the first resistor 7 is connected in parallel with the second dc capacitor 5, and then connected in series with the second power semiconductor device 16.
Optionally, the energy consumption unit 9 further includes a second resistor 13, the second resistor 13 is connected in parallel with the second dc capacitor 5, and the second resistor 13 includes, but is not limited to, a voltage-sharing resistor or/and a non-linear resistor.
As shown in fig. 2, the energy consuming unit 9 is located at the bottom of the commutation arm 21. One end of the energy consumption unit 9 is connected with the direct current cathode, and the other end is connected with the third power semiconductor device D1And (4) connecting.
Fig. 3 is a schematic diagram of another commutation arm structure provided in an embodiment of the present application.
In fig. 3, the commutation arm is similar to that of fig. 1. The difference is that the energy consumption unit 9 is not located at the top or bottom of the commutation arm, but located at the middle position of the commutation arm, in this embodiment, the energy consumption unit is located between the kth voltage-sharing unit and the kth +1 voltage-sharing unit, K is greater than or equal to 1 and less than or equal to M-1, and the voltage-sharing unit at the bottom is the 1 st voltage-sharing unit. One end of the energy consumption unit is connected with the third power semiconductor device of the Kth voltage-sharing unit and is defined as a direct current connection point, and the other end of the energy consumption unit is connected with the fourth power semiconductor device of the Kth voltage-sharing unit. In this embodiment, a fifth power semiconductor device D3, in this embodiment, a diode, is further added, and the diode D3 is located on the connection line between the dc connection point and the positive electrode of the dc capacitor of the K +1 th voltage-sharing unit. The arrangement direction of the diode D3 is the same as that of the third power semiconductor device of the original voltage-sharing unit, namely, after the energy consumption unit is added, a connecting diode is added, so that the connection of the direct current capacitor between the voltage-sharing units can not be interrupted.
Fig. 4 is a schematic diagram of a series high-voltage dc transformer according to an embodiment of the present disclosure.
The series high-voltage direct-current transformer comprises a direct-current converter 18, an isolation transformer 19 and an alternating-current direct-current converter 20.
The inverter 18 includes P inverting arms 21 as described above, where P is an integer of 2 or more. In the present embodiment, P is 2, and the number of commutation arms 21 in the inverter 18 is 2. The direct current positive electrode of the converter arm 21 of the direct-current-to-alternating converter 18 is connected as the direct current input positive electrode of the series high-voltage direct-current transformer, the direct current negative electrode of the converter arm 21 of the direct-current-to-alternating converter 18 is connected as the direct current input negative electrode of the series high-voltage direct-current transformer, and the alternating current end of the converter arm 21 of the direct-current-to-alternating converter 18 is used as the alternating current end of the direct-current-to-alternating converter.
The primary side of the isolation transformer 19 is connected to the ac terminal of the dc-ac converter 18. The ac-dc converter 20 is connected to the secondary side of the isolation transformer 19.
The ac-dc converter 20 includes P commutation arms 21 as described above, where P is 2 in the present embodiment, and the number of commutation arms 21 in the ac-dc converter 20 is also 2. The alternating current end of the converter arm 21 of the alternating current-direct current converter 20 is connected with the secondary side of the isolation transformer, the direct current positive electrode of the converter arm 21 of the alternating current-direct current converter 20 is connected as the direct current output positive electrode of the series high-voltage direct current transformer, and the direct current negative electrode of the converter arm 21 of the alternating current-direct current converter 20 is connected as the direct current output negative electrode of the series high-voltage direct current transformer.
The control method of the series high-voltage direct-current transformer comprises the following steps: and regulating the output voltage of the alternating current end of a converter arm 21 of the DC-AC converter 18, and controlling the AC-DC converter 20 to work until the DC output voltage of the series high-voltage DC transformer reaches a given target value.
Fig. 5 is a second schematic diagram of a series high-voltage dc transformer according to an embodiment of the present invention.
In this embodiment, unlike the embodiment of fig. 4, the commutation arm 21 in the dc-ac converter 18 includes more than one energy consuming unit. The commutation arm 21 of the ac-dc converter 20 comprises an energy consuming unit.
Fig. 6 is a third schematic diagram of a series high-voltage dc transformer according to an embodiment of the present invention.
The series high-voltage direct-current transformer comprises a direct-current converter 18, an isolation transformer 19 and an alternating-current direct-current converter 20.
The inverter 18 includes P inverting arms 21 as described above, where P is an integer of 2 or more. In the present embodiment, P is 2, and the number of commutation arms 21 in the inverter 18 is 2. The direct current positive electrode of the converter arm 21 of the direct-current-to-alternating converter 18 is connected as the direct current input positive electrode of the series high-voltage direct-current transformer, the direct current negative electrode of the converter arm 21 of the direct-current-to-alternating converter 18 is connected as the direct current input negative electrode of the series high-voltage direct-current transformer, and the alternating current end of the converter arm 21 of the direct-current-to-alternating converter 18 is used as the alternating current end of the direct-current-to-alternating converter.
The primary side of the isolation transformer 19 is connected to the ac terminal of the dc-ac converter 18. The ac-dc converter 20 is connected to the secondary side of the isolation transformer 19.
The ac-dc converter 20 comprises an uncontrolled rectifier bridge or a fully controlled rectifier bridge. In the present embodiment, the ac-dc converter 20 includes an uncontrolled rectifier bridge. The uncontrolled rectifier bridge comprises a bridge circuit consisting of diodes.
The control method of the series high-voltage direct-current transformer comprises the following steps: the output voltage at the ac side of the commutation limb 21 of the converter 18 is regulated until the dc output voltage of the series high voltage dc transformer reaches a given target value.
Fig. 7 is a fourth schematic diagram of a series high-voltage dc transformer according to an embodiment of the present disclosure.
The series high-voltage direct-current transformer comprises a direct-current converter 18, an isolation transformer 19 and an alternating-current direct-current converter 20.
The inverter 18 includes P inverting arms 21 as described above, where P is an integer of 2 or more. In this embodiment, P is 3, and the number of commutation arms 21 in the inverter 18 is 3. The direct current positive electrode of the converter arm 21 of the direct-current-to-alternating converter 18 is connected as the direct current input positive electrode of the series high-voltage direct-current transformer, the direct current negative electrode of the converter arm 21 of the direct-current-to-alternating converter 18 is connected as the direct current input negative electrode of the series high-voltage direct-current transformer, and the alternating current ends of the three converter arms 21 of the direct-current-to-alternating converter 18 are used as the three-phase alternating current ends of the direct-current-to-.
The primary side of the isolation transformer 19 is connected to the ac terminal of the dc-ac converter 18. The ac-dc converter 20 is connected to the secondary side of the isolation transformer 19.
The ac-dc converter 20 comprises an uncontrolled rectifier bridge or a fully controlled rectifier bridge. In the present embodiment, the ac-dc converter 20 includes a fully controlled rectifier bridge. The fully controlled rectifier bridge comprises a fully controlled power semiconductor device or a plurality of cascaded full bridge connected power units 1 or a plurality of cascaded half bridge connected power units 2. In the present embodiment, the fully-controlled rectifier bridge comprises a plurality of cascaded full-bridge connected power units 1, and the full-bridge connected power units 1 comprise second dc capacitors C2And a second direct currentCapacitor C2A parallel connected full bridge rectifier unit, as shown in figure 8,
fig. 8 is a schematic diagram of a power unit configured in a full-bridge connection according to an embodiment of the present application.
The control method of the series high-voltage direct-current transformer comprises the following steps: and regulating the output voltage of the alternating current end of a converter arm 21 of the DC-AC converter 18, and controlling the AC-DC converter 20 to work until the DC output voltage of the series high-voltage DC transformer reaches a given target value.
Fig. 9 is a fifth schematic diagram of a series high-voltage dc transformer according to an embodiment of the present application.
Unlike the embodiment of fig. 7, in the present embodiment, the ac-dc converter 20 includes a fully controlled rectifier bridge. The fully controlled rectifier bridge comprises a plurality of cascaded half-bridge connected power cells 2. The half-bridge connected power unit 2 comprises a second DC capacitor C2And a second DC capacitor C2Parallel-connected half-bridge rectification units, as shown in fig. 10, fig. 10 is a schematic diagram of a half-bridge-connected power unit according to an embodiment of the present application.
Fig. 11 is a sixth schematic diagram of a series high-voltage dc transformer according to an embodiment of the present application.
The series high voltage direct current transformer comprises a converter arm 21, a first converter chain 22 and a second converter chain 23 as described above. The dc positive pole of the converter arm 21 is connected as the dc input positive pole of the series high voltage dc transformer, and the dc negative pole of the converter arm 21 is connected as the dc input negative pole of the series high voltage dc transformer.
One end of the first converter chain 22 is connected with the ac end of the converter arm 21, the other end of the first converter chain 22 serves as the dc output positive pole of the series high-voltage dc transformer, and the dc output negative pole of the series high-voltage dc transformer is connected with the dc input negative pole. The first converter chain 22 includes at least N power cells 1 connected in full bridge in series, where N is an integer greater than or equal to 1, as shown in fig. 8, and fig. 8 is a schematic diagram of a power cell connected in full bridge according to an embodiment of the present disclosure.
And the second converter chain 23 is connected in parallel at two ends of the direct current output positive electrode and the direct current output negative electrode. The second commutation chain comprises a commutation arm 21 as described above, and the ac terminal of the commutation arm 21 is not drawn.
The control method of the series high-voltage direct-current transformer is as follows.
Setting a DC input voltage reference value U of a series high voltage DC transformerinReference value U of DC output voltage of series high-voltage DC transformerout(ii) a Entering a pre-charge mode; an upper arm of the commutation arm 21; regulating the DC output voltage of the second converter chain 23 until reaching the second DC capacitor C of the power unit 1 in the first converter chain 222To a nominal value; after entering the voltage regulation mode, the DC output voltage of the series high-voltage DC transformer is regulated to Uout。
Regulating the DC output voltage of a series high voltage DC transformer to UoutThe process comprises the following steps: the upper bridge arm of the commutation arm 21 is switched on, and the lower bridge arm of the commutation arm 21 is switched off; regulating the dc output voltage of the first inverter chain 22 to Uin-UoutRegulating the DC output voltage of the series high-voltage DC transformer to Uout(ii) a The lower arm of the commutation arm 21 is switched on, and the upper arm of the commutation arm 21 is switched off; adjusting the DC output voltage of the first converter chain to-UoutTo adjust the DC output voltage of the series high-voltage DC transformer to Uout。
The time for turning on the upper arm of the commutating arm 21 is the same as the time for turning on the lower arm of the commutating arm 21.
Fig. 12 is a seventh schematic diagram of a series high-voltage dc transformer according to an embodiment of the present application.
Different from the embodiment of fig. 11, in this embodiment, the second converter chain 23 includes at least N power units 1 connected in a full bridge in series, where N is an integer greater than or equal to 1, as shown in fig. 8, and fig. 8 is a schematic diagram of a configuration of a power unit connected in a full bridge according to an embodiment of the present application.
Fig. 13 is an eighth schematic diagram of a series high-voltage dc transformer according to an embodiment of the present application.
Unlike the embodiment of fig. 11, in this embodiment, the second converter chain 23 includes at least N half-bridge connected power cells 2 connected in series, where N is an integer greater than or equal to 1, as shown in fig. 10, and fig. 10 is a schematic diagram of a half-bridge connected power cell configuration provided in this embodiment of the present application.
The foregoing detailed description of the embodiments of the present application has been presented to illustrate the principles and implementations of the present application, and the description of the embodiments is only intended to facilitate the understanding of the methods and their core concepts of the present application. Meanwhile, a person skilled in the art should, according to the idea of the present application, change or modify the embodiments and applications of the present application based on the scope of the present application. In view of the above, the description should not be taken as limiting the application.
Claims (19)
1. A commutation arm, wherein a head end of the commutation arm is connected with a direct current positive electrode, a tail end of the commutation arm is connected with a direct current negative electrode, a midpoint of the commutation arm is led out to be used as an alternating current end of the commutation arm, and the commutation arm comprises:
m voltage-sharing units and R energy-consuming units, wherein M and R are integers more than or equal to 1; wherein, voltage-sharing unit includes:
the other end of the third power semiconductor device is connected with a connection point or an energy consumption unit of the third power semiconductor device and the fourth power semiconductor device of the adjacent voltage equalizing unit;
a first direct current capacitor having one end connected to a connection point of the third power semiconductor device and the fourth power semiconductor device,
and one end of the first power semiconductor device is connected with the other end of the first direct current capacitor, the other end of the first power semiconductor device is connected with the other end of the fourth power semiconductor device, and the first power semiconductor devices of the at least one voltage-sharing unit are sequentially connected in series in the same direction.
2. A commutating arm according to claim 1 wherein the first power semiconductor device comprises: a fully-controlled power semiconductor device.
3. A commutating arm according to claim 1 wherein the third and fourth power semiconductor devices each comprise: at least one of a diode or a fully controlled power semiconductor device.
4. A commutating arm according to claim 1 wherein the energy consuming unit comprises:
a first switch comprising a solid state switch or a mechanical switch comprised of a power semiconductor device;
a first resistor connected in series with the first switch;
and a second direct current capacitor connected in parallel with a series circuit of the first switch and the first resistor.
5. A commutating arm according to claim 4 wherein the energy consuming unit further comprises:
and the second power semiconductor device is connected in series after a series circuit of the first switch and the first resistor is connected in parallel with the second direct current capacitor.
6. A commutating arm according to claim 4 wherein the energy consuming unit further comprises:
and the second resistor is connected with the second direct current capacitor in parallel, and comprises a voltage-sharing resistor or/and a nonlinear resistor.
7. A series high voltage dc transformer comprising:
a dc-ac converter, comprising P converter arms according to any one of claims 1 to 6, where P is an integer greater than or equal to 2, a dc positive electrode of the converter arm is connected as a dc input positive electrode of the series high-voltage dc transformer, a dc negative electrode of the converter arm is connected as a dc input negative electrode of the series high-voltage dc transformer, and an ac end of the converter arm is used as an ac end of the dc-ac converter;
the primary side of the isolation transformer is connected with the alternating current end of the direct current-alternating current converter;
and the alternating current-direct current converter is connected with the secondary side of the isolation transformer.
8. The series hvdc transformer of claim 7, said ac to dc converter comprising:
and the alternating current ends of the converter arms are connected with the secondary side of the isolation transformer, the direct current positive electrodes of the converter arms are connected to be used as the direct current output positive electrodes of the series high-voltage direct current transformers, and the direct current negative electrodes of the converter arms are connected to be used as the direct current output negative electrodes of the series high-voltage direct current transformers.
9. The series hvdc transformer of claim 7, said ac to dc converter comprising:
an uncontrolled rectifier bridge or a fully controlled rectifier bridge;
the uncontrolled rectifier bridge comprises: a bridge circuit composed of diodes;
the full-controlled rectifier bridge comprises:
fully-controlled power semiconductor device, or
Cascaded a plurality of full bridge connection's power unit or half-bridge connection's power unit, the power unit of full bridge connection include second direct current electric capacity and with second direct current electric capacity parallel connection's full-bridge rectifier unit, the power unit of half-bridge connection or include second direct current electric capacity and with second direct current electric capacity parallel connection's half-bridge rectifier unit.
10. A method of controlling a series high voltage dc transformer according to any of claims 7 to 9, comprising:
adjusting the output voltage of the alternating current end of the current conversion arm of the direct current-alternating current converter;
and controlling the direct-current output voltage of the series high-voltage direct-current transformer to reach a given target value.
11. The control method of claim 10, wherein, if the ac-dc converter includes the uncontrolled rectifier bridge, the controlling the dc output voltage of the series high-voltage dc transformer to reach a given target value comprises:
and continuously adjusting the output voltage of the alternating current end until the direct current output voltage of the series high-voltage direct current transformer reaches a given target value.
12. The control method according to claim 10, wherein if the ac-dc converter includes P converter arms or the fully controlled rectifier bridge, the controlling the dc output voltage of the series high-voltage dc transformer to reach a given target value comprises:
and controlling the AC-DC converter to work until the DC output voltage of the series high-voltage DC transformer reaches a given target value.
13. A series high voltage dc transformer comprising:
the converter arm according to any of claims 1 to 6, wherein a direct current positive electrode of the converter arm is connected as a direct current input positive electrode of the series high voltage direct current transformer, and a direct current negative electrode of the converter arm is connected as a direct current input negative electrode of the series high voltage direct current transformer;
a first converter chain; one end of the converter arm is connected with the alternating current end of the converter arm, the other end of the converter arm is used as the direct current output positive electrode of the series high-voltage direct current transformer, and the direct current output negative electrode of the series high-voltage direct current transformer is connected with the direct current input negative electrode;
and the second commutation chain is connected in parallel at two ends of the direct current output positive electrode and the direct current output negative electrode.
14. The series high voltage direct current transformer of claim 13, the first converter chain comprising:
at least N power units connected in series in a full-bridge connection mode, wherein N is an integer greater than or equal to 1.
15. The series high voltage direct current transformer of claim 13, the second converter chain comprising:
at least N power units in a full-bridge connection form or a half-bridge connection form are connected in series, wherein N is an integer larger than or equal to 1.
16. The series high voltage direct current transformer of claim 13, the second converter chain comprising:
a commutating arm according to any of claims 1-6, the AC end of which is not tapped.
17. A method of controlling a series high voltage dc transformer according to any of claims 13 to 16, comprising:
setting a DC input voltage reference value U of the series high voltage DC transformerinA reference value U of the DC output voltage of the series high-voltage DC transformerout；
Entering a pre-charge mode;
conducting an upper bridge arm of the current conversion arm;
and regulating the direct-current output voltage of the second converter chain until the direct-current capacitance voltage of the power unit in the first converter chain reaches a rated value.
18. The control method of claim 17, wherein entering the voltage regulation mode after the pre-charge mode is completed comprises:
switching on an upper bridge arm of the current conversion arm and switching off a lower bridge arm of the current conversion arm;
adjusting the DC output voltage of the first converter chain to Uin-UoutAdjusting the DC output voltage of the series high-voltage DC transformer to be Uout；
Switching on a lower bridge arm of the current conversion arm and switching off an upper bridge arm of the current conversion arm;
adjusting the DC output voltage of the first converter chain to-UoutTo adjust the DC output voltage of the series high-voltage DC transformer to Uout。
19. The control method according to claim 18, wherein the time for conducting the upper arm of the commutation arm is the same as the time for conducting the lower arm of the commutation arm.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120228945A1 (en) * | 2011-03-07 | 2012-09-13 | Fuji Electric Co., Ltd. | Power converter |
| CN103107725A (en) * | 2013-02-06 | 2013-05-15 | 浙江大学 | Multi-level converter with direct current voltage reverse function |
| CN105226973A (en) * | 2015-09-24 | 2016-01-06 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Submodule can be turned off and the modified model half-bridge MMC-HVDC topology of DC Line Fault can be excised |
| CN105429496A (en) * | 2015-12-31 | 2016-03-23 | 北京四方继保自动化股份有限公司 | Modular multilevel converter with DC fault elimination function |
| CN109546638A (en) * | 2018-10-22 | 2019-03-29 | 南京南瑞继保电气有限公司 | A kind of direct current energy-consuming device and control method |
-
2019
- 2019-11-18 CN CN201911130085.4A patent/CN112821739B/en active Active
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120228945A1 (en) * | 2011-03-07 | 2012-09-13 | Fuji Electric Co., Ltd. | Power converter |
| CN103107725A (en) * | 2013-02-06 | 2013-05-15 | 浙江大学 | Multi-level converter with direct current voltage reverse function |
| CN105226973A (en) * | 2015-09-24 | 2016-01-06 | 中国南方电网有限责任公司超高压输电公司检修试验中心 | Submodule can be turned off and the modified model half-bridge MMC-HVDC topology of DC Line Fault can be excised |
| CN105429496A (en) * | 2015-12-31 | 2016-03-23 | 北京四方继保自动化股份有限公司 | Modular multilevel converter with DC fault elimination function |
| CN109546638A (en) * | 2018-10-22 | 2019-03-29 | 南京南瑞继保电气有限公司 | A kind of direct current energy-consuming device and control method |
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