CN115333135A - Control system of bipolar flexible direct current converter station - Google Patents
Control system of bipolar flexible direct current converter station Download PDFInfo
- Publication number
- CN115333135A CN115333135A CN202210576127.2A CN202210576127A CN115333135A CN 115333135 A CN115333135 A CN 115333135A CN 202210576127 A CN202210576127 A CN 202210576127A CN 115333135 A CN115333135 A CN 115333135A
- Authority
- CN
- China
- Prior art keywords
- voltage
- current
- converter
- negative
- valve
- 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.)
- Pending
Links
Images
Classifications
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/36—Arrangements for transfer of electric power between ac networks via a high-tension dc link
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/381—Dispersed generators
-
- 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
- H02M1/34—Snubber circuits
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2300/00—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation
- H02J2300/40—Systems for supplying or distributing electric power characterised by decentralized, dispersed, or local generation wherein a plurality of decentralised, dispersed or local energy generation technologies are operated simultaneously
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/60—Arrangements for transfer of electric power between AC networks or generators via a high voltage DC link [HVCD]
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Ac-Ac Conversion (AREA)
Abstract
The application provides a bipolar flexible direct current converter station control system, which is suitable for a bipolar flexible direct current transmission system accessed by a large-scale new energy pure island. The control device can comprise a bipolar alternating voltage outer ring controller, a valve side current inner ring controller of a positive pole and a negative pole, and a direct current side combined controller of the positive pole and the negative pole. The bipolar alternating-current voltage outer ring controller is used for realizing control of alternating-current side alternating-current voltage of the bipolar flexible direct-current converter station and distribution of positive and negative power reference values; the current inner loop controllers on the anode valve side and the cathode valve side respectively realize effective control of the current on the anode converter transformer valve side and the current on the cathode converter transformer valve side. This application can effectively provide stable alternating voltage and frequency for the access of new forms of energy power station.
Description
Technical Field
The application relates to the technical field of large-scale new energy flexible direct current long-distance power transmission engineering, in particular to a bipolar flexible direct current converter station control system.
Background
The new energy flexible direct current transmission project is long in transmission distance and large in capacity, a pure new energy access system is arranged on the sending end alternating current side, and a new energy power station and a sending end converter station are connected in an isolated island mode. Because the pure new energy access system has no power supplies such as a generator and the like, in order to ensure the normal operation of the new energy flexible direct current transmission project, a bipolar flexible direct current sending end converter station system with new energy intervention needs to provide stable alternating current voltage and frequency.
Therefore, it is always a concern about how to provide stable ac voltage and frequency for a bipolar flexible dc transmission end converter station system of a bipolar flexible dc transmission project with new energy access.
Disclosure of Invention
In view of the above, the present application provides a control system for a bipolar flexible dc converter station, which is used to solve the technical defect in the prior art that it is difficult to provide stable ac voltage and frequency for a bipolar flexible dc transmitting end converter station system of a bipolar flexible dc transmission project with new energy access.
A bipolar flexible direct current converter station control system is applied to a bipolar flexible direct current transmission system, and the bipolar flexible direct current transmission system comprises: bipolar flexible direct current send end converter station, new forms of energy power station, wherein, bipolar flexible direct current send end converter station and new forms of energy power station isolated island are connected, bipolar flexible direct current converter station control system includes: a positive pole converter, a negative pole converter, an alternating current side double closed-loop controller and a converter valve control which are arranged in the bipolar flexible direct current sending end converter station,
the converter valve control comprises a positive converter valve control body and a negative converter valve control body, the positive converter valve control body comprises a positive converter valve hybrid bridge module, the negative converter valve control body comprises a negative converter valve hybrid bridge module, and the alternating-current side double closed-loop controller comprises an alternating-current voltage outer loop controller, a positive-electrode valve side current inner loop controller and a negative-electrode valve side current inner loop controller;
the alternating voltage outer ring controller controls the alternating voltage shared by the alternating current side of the positive pole converter and the alternating current side of the negative pole converter, and outputs the alternating voltage to control the input of the positive pole valve side current inner ring controller and the negative pole valve side current inner ring controller according to a preset power distribution strategy;
the positive pole valve side current inner loop controller controls the valve side current of the positive pole converter, generates a three-phase alternating current voltage modulation wave reference value based on the input of the positive pole valve side current inner loop controller and a preset frequency, and transmits the three-phase alternating current voltage modulation wave reference value to the positive pole converter valve for valve control;
the negative pole valve side current inner loop controller controls the valve side current of the negative pole converter, generates a three-phase alternating current voltage modulation wave reference value based on the input of the negative pole valve side current inner loop controller and a preset frequency, and transmits the three-phase alternating current voltage modulation wave reference value to the negative pole converter valve for valve control;
and the converter valve control controls the switching of the positive pole converter valve hybrid bridge module and the negative pole converter valve hybrid bridge module based on a preset rated module voltage and the three-phase alternating current voltage modulation wave reference value, and generates a target alternating current side voltage and a target frequency.
Preferably, the method further comprises the following steps:
a positive direct current side combined controller and a negative direct current side combined controller which are arranged on the bipolar flexible direct current sending end converter station,
wherein the content of the first and second substances,
the positive pole direct current side combined controller controls the voltage of the positive pole converter valve hybrid bridge module based on a rated sub-module voltage reference value preset by a positive pole converter valve, outputs a direct current voltage reference value of a positive pole direct current side to the positive pole converter valve control, generates direct current voltage on the direct current side of the positive pole converter based on the direct current voltage reference value of the positive pole direct current side, and generates target positive pole converter valve hybrid bridge sub-module voltage through dynamic adjustment of the direct current voltage on the positive pole direct current side;
the negative pole direct current side combination controller controls the voltage of the negative pole converter valve hybrid bridge module based on a rated submodule voltage reference value preset by the negative pole converter valve, outputs a direct current voltage reference value of the negative pole direct current side to the negative pole converter valve control, the negative pole converter valve control generates direct current voltage on the direct current side of the negative pole converter, and the target negative pole converter valve hybrid bridge submodule voltage is generated through dynamic adjustment of the direct current voltage on the negative pole direct current side.
Preferably, the positive dc side combination controller includes a positive dc side sub-module voltage controller, a positive dc side current controller;
based on the control, the anode direct-current side combined controller controls the voltage of the anode converter valve hybrid bridge module and outputs a direct-current voltage reference value of the anode direct-current side to the valve control of the anode converter valve; the method comprises the following steps:
the voltage controller of the positive pole direct current side sub-module controls the voltage average value of the mixed bridge module of the positive pole converter valve and outputs a positive pole direct current control reference value to the positive pole direct current controller;
and the positive direct current controller outputs a positive direct current voltage control reference value to the positive converter valve control based on the positive direct current reference value.
Preferably, the negative dc side combination controller includes a negative dc side sub-module voltage controller, a negative dc side current controller;
based on the control, the negative direct current side combined controller controls the voltage of the negative converter valve hybrid bridge module and outputs a direct current voltage reference value of the negative direct current side to the valve control of the negative converter valve; the method comprises the following steps:
the negative direct current side sub-module voltage controller controls the voltage average value of the negative converter valve mixing bridge module and outputs a negative direct current control reference value to the negative direct current controller;
and the negative direct current controller outputs a negative direct current voltage control reference value to the negative converter valve control based on the negative direct current reference value.
Preferably, the preset rated module voltage includes a rated positive converter valve hybrid bridge module voltage generated by the positive dc-side combination controller and a rated negative converter valve hybrid bridge module voltage generated by the negative dc-side combination controller,
the positive converter valve control controls the switching of the positive converter valve hybrid bridge module based on the positive direct-current voltage control reference value and the three-phase alternating-current voltage modulation wave, and the negative converter valve control controls the switching of the negative converter valve hybrid bridge module based on the negative direct-current voltage control reference value and the three-phase alternating-current voltage modulation wave, and generates a target positive converter valve hybrid bridge submodule voltage, a target negative converter valve hybrid bridge submodule voltage, a target alternating-current side voltage and a target frequency.
Preferably, the ac voltage outer loop controller controls ac voltages of the positive converter and the negative converter, and controls inputs of the positive valve side current inner loop controller and the negative valve side current inner loop controller according to a preset power distribution strategy, including:
the alternating voltage outer ring controller outputs a target current reference value based on a preset rated voltage reference value;
and the alternating voltage outer ring controller respectively uses the target current reference value as the input of the positive valve side current inner ring controller and the negative valve side current inner ring controller according to a preset power distribution strategy.
Preferably, the positive pole valve side current inner loop controller controls the valve side current of the positive pole converter, and based on the input of the positive pole converter and a preset frequency, generates a three-phase alternating current voltage modulation wave reference value and transmits the reference value to the valve control of the positive pole converter valve, and the method includes:
and the current inner loop controller on the side of the anode valve generates a three-phase alternating current voltage modulation wave reference value based on the target current reference value and a preset frequency sum and transmits the three-phase alternating current voltage modulation wave reference value to the valve control of the anode converter valve.
Preferably, the negative pole valve side current inner loop controller controls the valve side current of the negative pole converter, generates a three-phase ac voltage modulation wave reference value based on the input of the negative pole converter and a preset frequency, and transmits the reference value to the negative pole converter valve control, and the negative pole converter valve control method includes:
and the negative valve side current inner loop controller generates a three-phase alternating current voltage modulation wave reference value based on the target current reference value and a preset frequency sum and transmits the three-phase alternating current voltage modulation wave reference value to the negative converter valve for valve control.
Preferably, the preset power allocation policy includes:
and distributing the current output by the alternating voltage outer loop controller to the positive valve side current inner loop controller and the negative valve side current inner loop controller according to a set proportion.
Preferably, the positive converter valve hybrid bridge module and the negative converter valve hybrid bridge module both include a full-bridge submodule and a half-bridge submodule.
As can be seen from the foregoing technical solutions, the embodiments of the present application may be applied to a bipolar flexible direct current power transmission system, where the bipolar flexible direct current power transmission system may include: bipolar flexible direct current send end converter station, new forms of energy power station, wherein, bipolar flexible direct current send end converter station with the new forms of energy power station island is connected, and this application can include: a positive pole converter, a negative pole converter, an alternating current side double closed-loop controller and a converter valve control which are arranged in the bipolar flexible direct current sending end converter station,
wherein the converter valve control can comprise a positive converter valve control and a negative converter valve control, the positive converter valve control can comprise a positive converter valve hybrid bridge module, the negative converter valve control module can comprise a negative converter valve hybrid bridge module, and the alternating-current side double closed-loop controller can comprise an alternating-current voltage outer loop controller, a positive valve side current inner loop controller and a negative valve side current inner loop controller; the ac voltage outer loop controller may control an ac voltage common to the ac side of the positive inverter and the ac side of the negative inverter so that an output thereof may control inputs of the positive valve side current inner loop controller and the negative valve side current inner loop controller according to a preset power distribution strategy. The positive pole valve side current inner loop controller can control the valve side current of the positive pole converter, can generate a three-phase alternating current voltage modulation wave reference value based on the input of the positive pole converter and a preset frequency and transmits the three-phase alternating current voltage modulation wave reference value to the positive pole converter valve controller; the negative pole valve side current inner loop controller can control the valve side current of the negative pole converter, can generate a three-phase alternating current voltage modulation wave reference value based on the input of the negative pole current converter and a preset frequency, and transmits the three-phase alternating current voltage modulation wave reference value to the negative pole converter valve for valve control; the converter valve control can control the switching of the positive pole converter valve mixing bridge module and the negative pole converter valve mixing bridge module based on a preset rated module voltage and the three-phase alternating current voltage modulation wave reference value so as to generate a target alternating current side voltage and a target frequency.
The method and the device can effectively provide stable alternating voltage and frequency for the bipolar flexible direct current sending end converter station flexible direct current system of the new energy flexible direct current transmission project.
Drawings
In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be 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 that other drawings can be obtained according to the drawings without inventive exercise.
Fig. 1 is a schematic diagram of an architecture for implementing a bipolar flexible dc transmitting end converter station control system according to an embodiment of the present application;
fig. 2 is a schematic structural diagram of a hybrid bridge module according to an embodiment of the present disclosure.
Detailed Description
The technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only some embodiments of the present application, and not all embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments in the present application without any creative effort belong to the protection scope of the present application.
The flexible direct current transmission is a new generation of direct current transmission technology, is similar to the high-voltage direct current transmission in structure, and still consists of a converter station and a direct current transmission line. Different from current source converter type high-voltage direct-current transmission based on a phase control commutation technology, converter stations at two ends in a flexible direct-current transmission system utilize flexible direct-current transmission and are composed of a converter, a converter transformer device, a converter reactance device and the like. The converter in the flexible direct current transmission is a voltage source converter and is mainly characterized in that a turn-off device (usually an IGBT) and a high-frequency modulation technology are adopted. The most critical core part is a voltage source converter, and the voltage source converter is composed of a rectifier bridge and a direct current capacitor. In the system, the topological structure of a main circuit and the type of a switching device are comprehensively considered, a sinusoidal pulse width modulation technology can be adopted, data comparison is carried out on the technology between a modulation reference wave and a triangular carrier wave, and the lower bridge arm switch can be triggered to be switched on and switched off under the condition that the data of the technology is relatively small. This is mainly due to the fact that both the floating value and the phase can be intelligently adjusted using pulse width modulation techniques. Therefore, the amplitude and phase of the fundamental frequency component of the alternating current output voltage of the voltage source converter can be adjusted through the pulse width.
The sending end alternating current side of the bipolar flexible direct current transmission system under the pure new energy access is a new energy island access system, and a bipolar flexible direct current sending end converter station flexible direct current system is required to provide stable alternating current voltage due to the fact that power sources such as a generator do not exist.
To this end, the applicant has studied a flexible dc converter station control scheme, which may be applied to a bipolar flexible dc transmission system, which may include: the system comprises a bipolar flexible direct current sending end converter station and a new energy power station, wherein the bipolar flexible direct current sending end converter station is connected with the new energy power station in an isolated island mode. The method aims to provide stable alternating voltage and frequency for a bipolar flexible direct current sending end converter station flexible direct current system of a new energy flexible direct current transmission project.
An alternative system architecture that may implement the control of the flexible dc converter station according to the embodiment of the present application is described below with reference to fig. 1, and as shown in fig. 1, the system architecture may include: a positive pole converter, a negative pole converter, an alternating current side double closed-loop controller and a converter valve control which are arranged in the bipolar flexible direct current sending end converter station,
the converter valve control may include a positive converter valve control and a negative converter valve control, the positive converter valve control may include a positive converter valve hybrid bridge module, the negative converter valve control may include a negative converter valve hybrid bridge module, and the ac-side dual closed-loop controller may include an ac voltage outer loop controller, a positive-side current inner loop controller, and a negative-side current inner loop controller.
The alternating voltage outer loop controller can control the alternating voltage shared by the alternating current side of the positive pole converter and the alternating current side of the negative pole converter, and can control the input of the positive pole valve side current inner loop controller and the input of the negative pole valve side current inner loop controller according to a preset power distribution strategy.
Specifically, the new energy flexible direct current transmission system adopts a bipolar direct current transmission control system, only one alternating current voltage control point is set for the bipolar flexible direct current sending end converter station, and only one alternating current voltage outer ring controller is designed in the bipolar direct current transmission control system, so that the output result of the alternating current voltage outer ring controller can be distributed to the inner ring controller corresponding to the bipolar transmission line according to a preset power distribution strategy.
For example, an ac side double closed-loop controller may be provided at the bipolar flexible dc transmitting end converter station, the ac side double closed-loop controller may be controlled by an ac voltage d-axis component and a q-axis component, and the positive valve side current inner-loop controller and the negative valve side current inner-loop controller may be controlled by a valve side current d-axis component and a q-axis component. When the bipolar direct-current transmission system normally operates, the alternating-current side double closed-loop controller can realize stable control of alternating-current side voltage and frequency of the bipolar flexible direct-current sending end converter station and average distribution of power of the positive direct-current transmission line and the negative direct-current transmission line.
For example, the ac voltage outer loop controller may control the inputs of the positive valve side current inner loop controller and the negative valve side current inner loop controller according to a preset power distribution strategy. So that the current and power of the positive valve side current inner loop controller and the negative valve side current inner loop controller can be evenly distributed.
Compared with a single-loop control strategy, the double-closed-loop control strategy can realize stable control of alternating voltage and frequency and control the current on the valve side within an amplitude limiting range, so that the current of a bridge arm of the hybrid bridge module is prevented from exceeding the limited current.
The positive pole valve side current inner loop controller can control the valve side current of the positive pole converter, and can generate a three-phase alternating current voltage modulation wave reference value based on the input of the positive pole converter and the preset frequency and transmit the three-phase alternating current voltage modulation wave reference value to the positive pole converter valve for valve control.
The negative pole valve side current inner loop controller can control the valve side current of the negative pole converter, can generate a three-phase alternating current voltage modulation wave reference value based on the input of the negative pole converter and preset frequency, and transmits the three-phase alternating current voltage modulation wave reference value to the negative pole converter valve control.
Specifically, the positive-electrode-side current inner-loop controller and the negative-electrode-side current inner-loop controller respectively correspond to a positive-electrode direct-current power transmission system and a negative-electrode direct-current power transmission system of a bipolar direct-current power transmission system, and under the control of the alternating-current voltage outer-loop controller, the positive-electrode-side current inner-loop controller and the negative-electrode-side current inner-loop controller can generate a three-phase alternating-current voltage modulation wave reference value and transmit the three-phase alternating-current voltage modulation wave reference value to the converter valve control based on the input controlled by the alternating-current voltage outer-loop controller and a preset frequency, so that the converter valve control can generate stable voltage and frequency.
Wherein the preset power allocation policy may be as follows:
and distributing the current output by the alternating voltage outer loop controller to the positive valve side current inner loop controller and the negative valve side current inner loop controller according to a set proportion.
The three-phase alternating voltage modulation wave reference value is that the positive electrode valve side current inner loop controller and the negative electrode valve side current inner loop controller convert d-axis and q-axis components of output voltage of the alternating voltage outer loop controller into abc three-phase alternating current components. The three-phase alternating current signals are respectively bridge arm modulation wave signals of a mixed bridge module controlled by the three-phase converter valve.
For example, a preset frequency may be set to 50Hz, and the positive electrode valve side current inner loop controller and the negative electrode valve side current inner loop controller may generate a three-phase ac voltage modulation wave reference value based on the current reference value controlled by the ac voltage outer loop controller and the frequency of 50Hz, and transmit the three-phase ac voltage modulation wave reference value to the converter valve control unit, so that the converter valve control unit may generate a stable voltage and frequency.
The converter valve control can control the switching of the positive pole converter valve mixing bridge module and the negative pole converter valve mixing bridge module based on a preset rated module voltage and the three-phase alternating voltage modulation wave reference value so as to generate a target alternating-current side voltage and a target frequency.
Specifically, the converter valve control may control the voltage of the hybrid bridge module, and after receiving the three-phase ac voltage modulation wave reference values transmitted by the positive-pole valve-side current inner loop controller and the negative-pole valve-side current inner loop controller, the converter valve control may control switching of the voltage of the hybrid bridge module based on a rated voltage of the hybrid bridge module and the three-phase ac voltage modulation wave reference values to generate a stable ac-side voltage and frequency.
The hybrid bridge module may include a full bridge sub-module and a half bridge sub-module.
In the above-described figure 1 of the drawings,
U d and U q Can respectively representD-and q-axis components of the AC voltage, U d And U q Can be obtained by converting abc/dq for three-phase alternating voltage;
I dref 、I qref can respectively represent the current reference value, I, of the valve-side current controller dref Can be a d-axis current reference value, I qref May be a q-axis current reference;
f may be frequency;
U cavg may be a sub-module voltage average;
m dc the reference value of the direct current voltage output by the direct current side combination controller can be obtained;
U iref can be a reference value of a three-phase voltage modulation wave.
According to the technical scheme, the switching of the positive pole converter valve hybrid bridge module and the negative pole converter valve hybrid bridge module can be controlled by utilizing the converter valve control based on the preset rated module voltage and the three-phase alternating current voltage modulation wave reference value, the target sub-module voltage, the target alternating current side voltage and the target frequency are generated, and the stable alternating current voltage and the stable alternating current frequency are effectively provided for the bipolar flexible direct current sending end converter station flexible direct current system of the new energy flexible direct current transmission project.
As can be seen from the above description, the converter valve control may control switching of the positive converter valve hybrid bridge module and the negative converter valve hybrid bridge module based on a rated hybrid bridge module voltage and the three-phase ac voltage modulation wave reference value to generate a target ac side voltage and a target frequency. In practical application, in order to ensure that the valve control of the converter valve can normally operate, the bipolar flexible direct current converter station control system further includes: a positive pole direct current converter and a negative pole direct current converter which are arranged in the bipolar flexible direct current sending end converter station, a positive pole direct current side combined controller and a negative pole direct current side combined controller,
wherein the content of the first and second substances,
the positive pole direct current side combination controller controls the voltage of the positive pole converter valve hybrid bridge module based on a rated sub-module voltage reference value preset by a positive pole converter valve, outputs a direct current voltage reference value of a positive pole direct current side to the positive pole converter valve control, generates direct current voltage on the direct current side of the positive pole converter based on the direct current voltage reference value of the positive pole direct current side, and generates target positive pole converter valve hybrid bridge sub-module voltage through dynamic adjustment of the direct current voltage on the positive pole direct current side.
Specifically, in order to ensure the normal operation of the converter valve control, the positive dc-side combination controller controls the voltage of the positive converter valve hybrid bridge module based on a preset rated sub-module voltage reference value of the positive converter valve, and outputs a dc voltage reference value on the positive dc side to the positive converter valve control, so that the converter valve control can generate a dc voltage on the dc side of the positive converter valve at the voltage reference value on the positive dc side, and effectively maintain stable operation through dynamic adjustment of the dc voltage on the positive dc side, thereby generating a stable target positive converter valve hybrid bridge sub-module voltage.
The negative pole direct current side combination controller controls the voltage of the negative pole converter valve hybrid bridge module based on a rated submodule voltage reference value preset by the negative pole converter valve, outputs a direct current voltage reference value of the negative pole direct current side to the negative pole converter valve control, the negative pole converter valve control generates direct current voltage on the direct current side of the negative pole converter, and the target negative pole converter valve hybrid bridge submodule voltage is generated through dynamic adjustment of the direct current voltage on the negative pole direct current side.
Specifically, in order to ensure the normal operation of the converter valve control, the cathode direct current side combination controller controls the cathode converter valve hybrid bridge module voltage based on a rated sub-module voltage reference value preset by a cathode converter valve, and outputs a cathode direct current side direct current voltage reference value to the cathode converter valve control, so that the converter valve control can maintain stable operation at the cathode direct current side voltage reference value, and a direct current voltage can be generated at the direct current side of the cathode converter. And generating the voltage of the target negative pole converter valve hybrid bridge submodule through the dynamic adjustment of the direct current voltage at the negative pole direct current side.
According to the technical scheme, the positive pole direct current side combined controller controls the voltage of the target positive pole converter valve hybrid bridge submodule based on the rated submodule voltage reference value preset by the positive pole converter valve, the negative pole direct current side combined controller controls the voltage of the target negative pole converter valve hybrid bridge submodule based on the rated submodule voltage reference value preset by the negative pole converter valve, and respectively outputs the voltage reference value of the positive pole direct current side and the voltage reference value of the negative pole direct current side to the converter valve control, so that the converter valve control can normally operate.
In practical applications, the positive dc side combination controller may include a positive dc side sub-module voltage controller and a positive dc side controller, and the negative dc side combination controller may include a negative dc side sub-module voltage controller and a negative dc side controller. The process of controlling the voltage of the positive converter valve hybrid bridge module by the positive dc side combination controller based on a preset rated sub-module voltage reference value of the positive converter valve and controlling the voltage of the negative converter valve hybrid bridge module by the negative dc side combination controller based on a preset rated sub-module voltage reference value of the negative converter valve and outputting the voltage reference value of the positive dc side and the voltage reference value of the negative dc side to the converter valve respectively may include the following steps:
the voltage controller of the anode direct current side module can control the voltage average value of each sub-module of the anode converter valve hybrid bridge module and output an anode direct current control reference value to the anode direct current controller;
the positive direct current controller can output a positive direct current voltage control reference value to the converter valve control based on the positive direct current reference value.
The negative direct current side module voltage controller can control the voltage average value of each submodule of the negative converter valve hybrid bridge module and output a negative direct current control reference value to the negative direct current controller;
the negative direct current controller can output a negative direct current voltage control reference value to the converter valve control based on the negative direct current reference value.
According to the technical scheme, the positive direct-current side combination controller controls the voltage of the positive converter valve hybrid bridge module based on the preset rated sub-module voltage reference value of the positive converter valve, and the negative direct-current side combination controller controls the voltage of the negative converter valve hybrid bridge module based on the preset rated sub-module voltage reference value of the negative converter valve, and respectively outputs the voltage reference value of the positive direct-current side and the voltage reference value of the negative direct-current side to the converter valve control, so that the converter valve control can normally operate.
According to the technical scheme, the converter valve control can control the switching of the positive converter valve hybrid bridge module and the negative converter valve hybrid bridge module based on a preset rated module voltage and the three-phase alternating-current voltage modulation wave reference value, and generate a target positive converter valve hybrid bridge submodule voltage, a target negative converter valve hybrid bridge submodule voltage, a target alternating-current side voltage and a target frequency, and the preset rated module voltage can include a rated positive converter valve hybrid bridge module voltage generated by the positive direct-current side combination controller and a rated negative converter valve hybrid bridge module voltage generated by the negative direct-current side combination controller. Therefore, the process of controlling the converter valve to switch the positive converter valve hybrid bridge module and the negative converter valve hybrid bridge module and generate a target positive converter valve hybrid bridge submodule voltage, a target negative converter valve hybrid bridge submodule voltage, a target alternating-current side voltage and a target frequency based on the preset rated module voltage and the three-phase alternating-current voltage modulation wave reference value may include the following steps:
the positive converter valve control can be based on the positive direct-current voltage control reference value and the three-phase alternating-current voltage modulation wave, so that the switching of the positive converter valve hybrid bridge module can be controlled, and the negative converter valve control can be based on the negative direct-current voltage control reference value and the three-phase alternating-current voltage modulation wave, so that the switching of the negative converter valve hybrid bridge module can be controlled, and therefore the target positive converter valve hybrid bridge submodule voltage, the target negative converter valve hybrid bridge submodule voltage, the target alternating-current side voltage and the target frequency can be generated.
According to the technical scheme, the converter valve control can control the switching of the anode converter valve hybrid bridge module and the cathode converter valve hybrid bridge module based on the preset rated module voltage and the three-phase alternating-current voltage modulation wave reference value, and generate the target anode converter valve hybrid bridge submodule voltage, the target cathode converter valve hybrid bridge submodule voltage, the target alternating-current side voltage and the target frequency, so that stable alternating-current voltage and frequency can be effectively provided for a bipolar flexible direct-current sending end converter station flexible direct-current system of a new energy flexible direct-current transmission project.
As can be seen from the above-described technical solutions, the ac voltage outer loop controller according to the embodiment of the present application may control the inputs of the positive electrode valve side current inner loop controller and the negative electrode valve side current inner loop controller according to a preset power distribution strategy, and the following process is described, and the process may include the following steps:
the ac voltage outer loop controller may output a target current reference value based on a preset rated voltage.
After obtaining the target current reference value, the ac voltage outer loop controller may respectively use the target current reference value as an input of the positive valve side current inner loop controller and an input of the negative valve side current inner loop controller according to a preset power distribution strategy.
Wherein the preset power distribution strategy may be set with reference to the target current reference value and an operation condition of the bipolar power transmission line.
Based on this, the process that the positive pole valve side current inner loop controller controls the valve side current of the positive pole converter, and generates and transmits the three-phase alternating current voltage modulation wave reference value to the valve control of the positive pole converter valve based on the input of the positive pole converter and the preset frequency may include the following steps:
the positive valve side current inner loop controller and the negative valve side current inner loop controller can generate a three-phase alternating current voltage modulation wave reference value based on a preset frequency and the target current reference value and transmit the three-phase alternating current voltage modulation wave reference value to the valve control of the converter valve.
The process that the negative pole valve side current inner loop controller controls the valve side current of the negative pole converter, and generates a three-phase alternating current voltage modulation wave reference value and transmits the reference value to the negative pole converter valve control based on the input of the negative pole converter and the preset frequency can comprise the following steps:
the negative valve side current inner loop controller can generate a three-phase alternating current voltage modulation wave reference value based on the target current reference value and a preset frequency sum, and transmits the three-phase alternating current voltage modulation wave reference value to the negative converter valve for valve control.
As can be seen from the above-mentioned introduced technical solutions, the ac voltage outer loop controller according to the embodiment of the present application may control the inputs of the positive electrode side current inner loop controller and the negative electrode side current inner loop controller according to a preset power distribution strategy, so that the positive electrode side current inner loop controller and the negative electrode side current inner loop controller may generate a three-phase ac voltage modulation wave reference value based on the inputs and a preset frequency, and transmit the three-phase ac voltage modulation wave reference value to the converter valve controller, so that the converter valve controller may generate a stable ac side voltage and frequency on the ac side based on the three-phase ac voltage modulation wave reference value, and may effectively provide a stable ac voltage and frequency for a bipolar flexible dc transmitting end converter station flexible dc system of a new energy flexible dc power transmission project.
As can be seen from the above description, the embodiments of the present application include a hybrid bridge module, and FIG. 2 illustrates a schematic structural view of the hybrid bridge module. The hybrid bridge module may include a number of full-bridge sub-modules and a number of half-bridge sub-modules.
Because the converter valve can comprise 6 bridge arms, each bridge arm can be formed by connecting a plurality of full-bridge sub-modules and half-bridge sub-modules in series.
The full-bridge submodule can be formed by 4 full-control devices IGBT and capacitors, and can comprise three states due to the increase of the number of the IGBTs: a positive input state, a negative input state, and an off state. When the full-bridge sub-module is in a positive input state, the voltage in a series loop of the full-bridge sub-module is positive; when the full-bridge submodule is in an inverse-input state, the voltage of the full-bridge submodule is negative; when the full-bridge sub-module is in the cut-off state, the voltage of the full-bridge sub-module is 0.
The half-bridge submodule can be formed by 2 full-control devices IGBT and capacitors, and can comprise two states: an input state and an excision state. When the half-bridge sub-module is in an on state, the voltage in a series circuit of the half-bridge sub-module is positive, and when the half-bridge sub-module is in an off state, the voltage of the half-bridge sub-module is 0;
because the inverter functions as AC-DC conversion, the modules of the upper and lower bridge arms are fixed. If the converter valve is composed of half-bridge sub-modules, the direct-current side voltage of the converter does not have the adjusting capability, and the direct-current side voltage of the converter can be 1pu; if the converter valve is composed of full-bridge submodules, the direct-current side voltage of the converter can be adjusted within the range of [ -1pu,1pu ], but if the converter valve is composed of full-bridge submodules, the direct-current side voltage of the converter can be adjusted flexibly, but the manufacturing cost is high. In consideration of economic applicability of electrical equipment and consideration of the fact that certain negative voltage can appear when direct-current side voltage needs to be achieved, in order to be used for clearing direct-current side faults, a mixed bridge module formed by a full-bridge submodule and a half-bridge submodule according to a certain proportion can be considered.
For example, the full-bridge sub-modules and the half-bridge sub-modules may be arranged to form a hybrid bridge module according to a ratio of 7:3, so that the dc-side voltage range of the converter may be [ -0.4pu,1pu ].
It can be known from the above-described technical solutions that the hybrid bridge module 3 according to the embodiment of the present application may include a plurality of full-bridge submodules and half-bridge submodules, so that it may be ensured that a voltage range of a dc side of the converter is within a preset range, which is beneficial for the converter valve to control the converter valve to generate stable voltage and current at an ac side.
Finally, it should also be noted that, in this document, relational terms such as first and second, and the like are used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising a … …" does not exclude the presence of another identical element in a process, method, article, or apparatus that comprises the element.
In the present specification, the embodiments are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.
The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. The various embodiments may be combined with each other. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
Claims (10)
1. A bipolar flexible direct current converter station control system is characterized by being applied to a bipolar flexible direct current transmission system, and the bipolar flexible direct current transmission system comprises: bipolar flexible direct current send end converter station, new forms of energy power station, wherein, bipolar flexible direct current send end converter station and new forms of energy power station isolated island are connected, bipolar flexible direct current converter station control system includes: a positive pole converter, a negative pole converter, an alternating current side double closed-loop controller and a converter valve control which are arranged in the bipolar flexible direct current sending end converter station,
the converter valve control comprises a positive converter valve control body and a negative converter valve control body, the positive converter valve control body comprises a positive converter valve mixing bridge module, the negative converter valve control body comprises a negative converter valve mixing bridge module, and the alternating-current side double-closed-loop controller comprises an alternating-current voltage outer loop controller, a positive-electrode valve side current inner loop controller and a negative-electrode valve side current inner loop controller;
the alternating voltage outer ring controller controls the alternating voltage shared by the alternating current side of the positive pole converter and the alternating current side of the negative pole converter, and outputs the alternating voltage to control the input of the positive pole valve side current inner ring controller and the negative pole valve side current inner ring controller according to a preset power distribution strategy;
the positive pole valve side current inner loop controller controls the valve side current of the positive pole converter, generates a three-phase alternating current voltage modulation wave reference value based on the input of the positive pole converter and a preset frequency and transmits the three-phase alternating current voltage modulation wave reference value to the positive pole converter valve for valve control;
the negative pole valve side current inner loop controller controls the valve side current of the negative pole converter, generates a three-phase alternating current voltage modulation wave reference value based on the input of the negative pole converter and a preset frequency and transmits the three-phase alternating current voltage modulation wave reference value to the negative pole converter valve for valve control;
the converter valve control controls the switching of the positive pole converter valve hybrid bridge module and the negative pole converter valve hybrid bridge module based on a preset rated module voltage and the three-phase alternating current voltage modulation wave reference value, and generates a target alternating current side voltage and a target frequency.
2. The bipolar flexible dc converter station control system according to claim 1, further comprising:
a positive direct current side combined controller and a negative direct current side combined controller which are arranged on the bipolar flexible direct current sending end converter station,
wherein, the first and the second end of the pipe are connected with each other,
the positive pole direct current side combined controller controls the voltage of the positive pole converter valve hybrid bridge module based on a rated sub-module voltage reference value preset by a positive pole converter valve, outputs a direct current voltage reference value of a positive pole direct current side to the positive pole converter valve control, generates direct current voltage on the direct current side of the positive pole converter based on the direct current voltage reference value of the positive pole direct current side, and generates target positive pole converter valve hybrid bridge sub-module voltage through dynamic adjustment of the direct current voltage of the positive pole direct current side;
the negative pole direct current side combination controller controls the voltage of the negative pole converter valve hybrid bridge module based on a preset rated sub-module voltage reference value of the negative pole converter valve, outputs a direct current voltage reference value of the negative pole direct current side to the negative pole converter valve control, the negative pole converter valve control generates direct current voltage on the direct current side of the negative pole converter, and the target negative pole converter valve hybrid bridge sub-module voltage is generated through dynamic adjustment of the direct current voltage on the negative pole direct current side.
3. The bipolar flexible dc converter station control system according to claim 2, wherein the positive dc side combination controller comprises a positive dc side sub-module voltage controller, a positive dc side current controller;
based on the control, the anode direct-current side combined controller controls the voltage of the anode converter valve hybrid bridge module and outputs a direct-current voltage reference value of the anode direct-current side to the valve control of the anode converter valve; the method comprises the following steps:
the voltage controller of the positive pole direct current side sub-module controls the voltage average value of the mixed bridge module of the positive pole converter valve and outputs a positive pole direct current control reference value to the positive pole direct current controller;
and the positive direct current controller outputs a positive direct current voltage control reference value to the positive converter valve control based on the positive direct current reference value.
4. The bipolar flexible dc converter station control system according to claim 2, wherein the negative dc side combination controller comprises a negative dc side sub-module voltage controller, a negative dc side current controller;
based on the voltage, the negative direct current side combination controller controls the voltage of the negative converter valve hybrid bridge module and outputs a direct current voltage reference value of the negative direct current side to the negative converter valve for valve control; the method comprises the following steps:
the voltage controller of the negative direct current side sub-module controls the voltage average value of the negative converter valve mixing bridge module and outputs a negative direct current control reference value to the negative direct current controller;
and the negative direct current controller outputs a negative direct current voltage control reference value to the negative converter valve control based on the negative direct current reference value.
5. The bipolar flexible dc converter station control system according to claim 2, wherein the preset rated module voltage comprises a rated positive converter valve hybrid bridge module voltage generated by the positive dc side combination controller and a rated negative converter valve hybrid bridge module voltage generated by the negative dc side combination controller,
the positive converter valve control controls the switching of the positive converter valve hybrid bridge module based on the positive direct-current voltage control reference value and the three-phase alternating-current voltage modulation wave, and the negative converter valve control controls the switching of the negative converter valve hybrid bridge module based on the negative direct-current voltage control reference value and the three-phase alternating-current voltage modulation wave, and generates a target positive converter valve hybrid bridge submodule voltage, a target negative converter valve hybrid bridge submodule voltage, a target alternating-current side voltage and a target frequency.
6. The bipolar flexible dc converter station control system according to claim 1, wherein said ac voltage outer loop controller controls ac voltages of said positive converter and said negative converter, and controls inputs of said positive valve side current inner loop controller and said negative valve side current inner loop controller according to a preset power distribution strategy, and comprises:
the alternating voltage outer ring controller outputs a target current reference value based on a preset rated voltage reference value;
and the alternating voltage outer ring controller respectively uses the target current reference value as the input of the positive valve side current inner ring controller and the negative valve side current inner ring controller according to a preset power distribution strategy.
7. The bipolar flexible dc converter station control system according to claim 6, wherein the positive electrode valve side current inner loop controller controls the valve side current of the positive electrode converter, and based on its input and a preset frequency, generates a three-phase ac voltage modulated wave reference value and transmits it to the positive electrode converter valve controller, comprising:
and the current inner loop controller on the side of the anode valve generates a three-phase alternating current voltage modulation wave reference value based on the target current reference value and a preset frequency sum and transmits the three-phase alternating current voltage modulation wave reference value to the valve control of the anode converter valve.
8. The bipolar flexible dc converter station control system according to claim 6, wherein the negative pole valve side current inner loop controller controls the valve side current of the negative pole converter, and based on its input and a preset frequency, generates a three-phase ac voltage modulation wave reference value and transmits it to the negative pole converter valve controller, comprising:
and the negative valve side current inner loop controller generates a three-phase alternating current voltage modulation wave reference value based on the target current reference value and a preset frequency sum and transmits the three-phase alternating current voltage modulation wave reference value to the negative converter valve for valve control.
9. The bipolar flexible direct current converter station control system according to claim 1, wherein the preset power distribution strategy comprises:
and distributing the current output by the alternating voltage outer loop controller to the positive valve side current inner loop controller and the negative valve side current inner loop controller according to a set proportion.
10. The bipolar flexible dc converter station control system according to any one of claims 1 to 9, wherein said positive converter valve hybrid bridge module and said negative converter valve hybrid bridge module each comprise a full bridge sub-module and a half bridge sub-module.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210576127.2A CN115333135A (en) | 2022-05-25 | 2022-05-25 | Control system of bipolar flexible direct current converter station |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210576127.2A CN115333135A (en) | 2022-05-25 | 2022-05-25 | Control system of bipolar flexible direct current converter station |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115333135A true CN115333135A (en) | 2022-11-11 |
Family
ID=83915685
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210576127.2A Pending CN115333135A (en) | 2022-05-25 | 2022-05-25 | Control system of bipolar flexible direct current converter station |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115333135A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115764929A (en) * | 2022-11-28 | 2023-03-07 | 浙江大学 | Backup voltage frequency supporting method for 100% new energy source sending end power grid |
| US11901739B2 (en) | 2022-11-28 | 2024-02-13 | Zhejiang University | Backup voltage and frequency support method for 100%-renewable energy sending-end grid |
-
2022
- 2022-05-25 CN CN202210576127.2A patent/CN115333135A/en active Pending
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115764929A (en) * | 2022-11-28 | 2023-03-07 | 浙江大学 | Backup voltage frequency supporting method for 100% new energy source sending end power grid |
| CN115764929B (en) * | 2022-11-28 | 2023-06-23 | 浙江大学 | Backup voltage frequency supporting method for 100% new energy source power grid |
| US11901739B2 (en) | 2022-11-28 | 2024-02-13 | Zhejiang University | Backup voltage and frequency support method for 100%-renewable energy sending-end grid |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Varajao et al. | Modulation strategy for a single-stage bidirectional and isolated AC–DC matrix converter for energy storage systems | |
| EP3514936B1 (en) | Hybrid dc converter for offshore wind farm | |
| Joos et al. | Direct-coupled multilevel cascaded series VAR compensators | |
| WO2015176549A1 (en) | Tripolar flexible direct-current power transmission system and method | |
| US9007792B2 (en) | Arrangement for transmitting power between a DC power line and an AC power line | |
| Miura et al. | Modular multilevel matrix converter for low frequency AC transmission | |
| CN115333135A (en) | Control system of bipolar flexible direct current converter station | |
| CN110798090A (en) | Combined modular multilevel converter topology and modulation method thereof | |
| Abdel-Moamen et al. | France-Spain HVDC transmission system with hybrid modular multilevel converter and alternate-arm converter | |
| CN210693795U (en) | Combined modular multilevel converter topology | |
| WO2010124634A1 (en) | High voltage power conversion device | |
| Rao et al. | Grid Connected Distributed Generation System with High Voltage Gain Cascaded DC-DC Converter Fed Asymmetric Multilevel Inverter Topology. | |
| CN116316782A (en) | Mixed light offshore wind power direct current transmission system and method | |
| CN105656336A (en) | Converter structure for reducing direct-current side harmonics | |
| CN114050727A (en) | Circuit topology structure of LCC-MMC mixed type AC-AC converter | |
| CN112290574B (en) | Current collector suitable for direct current collection and control method thereof | |
| Xia et al. | Dual phase shift PWM-CSCs based hybrid HVDC transmission system | |
| CN112688355A (en) | Hybrid direct current converter applied to offshore wind farm and control method thereof | |
| Woldegiorgis et al. | The Star-Switched MMC (SSMMC)-a hybrid VSC for HVDC applications | |
| CN111030483A (en) | Power electronic transformer and control method | |
| CN113452276B (en) | CCC-PHC type hybrid cascade direct current converter, rectifying station, inverter station and power transmission system | |
| CN115276433A (en) | Hydrogen production converter | |
| CN115036907A (en) | Battery energy storage medium-voltage direct current grid-connected system and method | |
| Abdel-Moamen et al. | Faults analysis for combined MMC and AAC with practical HVDC grid | |
| CN114826008B (en) | Control system and method for reducing bridge arm current peak value of MMC (Modular multilevel converter) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |