CN117613841A - Power grid interface conversion system and control method thereof - Google Patents
Power grid interface conversion system and control method thereof Download PDFInfo
- Publication number
- CN117613841A CN117613841A CN202311654673.4A CN202311654673A CN117613841A CN 117613841 A CN117613841 A CN 117613841A CN 202311654673 A CN202311654673 A CN 202311654673A CN 117613841 A CN117613841 A CN 117613841A
- Authority
- CN
- China
- Prior art keywords
- thyristor
- current
- zero
- energy transfer
- direct current
- 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
- 238000006243 chemical reaction Methods 0.000 title claims abstract description 33
- 238000000034 method Methods 0.000 title claims abstract description 19
- 238000012546 transfer Methods 0.000 claims abstract description 57
- 239000003990 capacitor Substances 0.000 claims abstract description 42
- 230000002238 attenuated effect Effects 0.000 claims description 12
- 230000001960 triggered effect Effects 0.000 claims description 12
- 230000007935 neutral effect Effects 0.000 claims description 7
- 230000005540 biological transmission Effects 0.000 description 14
- 238000010586 diagram Methods 0.000 description 14
- 238000004088 simulation Methods 0.000 description 7
- 230000000295 complement effect Effects 0.000 description 4
- 238000005516 engineering process Methods 0.000 description 3
- 230000005404 monopole Effects 0.000 description 3
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 238000012795 verification Methods 0.000 description 1
- 238000010792 warming Methods 0.000 description 1
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
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
-
- 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
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
- H02J1/06—Two-wire systems
-
- 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
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
- H02J1/08—Three-wire systems; Systems having more than three wires
-
- 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
- H02J1/00—Circuit arrangements for dc mains or dc distribution networks
- H02J1/08—Three-wire systems; Systems having more than three wires
- H02J1/082—Plural DC voltage, e.g. DC supply voltage with at least two different DC voltage levels
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Control Of Electrical Variables (AREA)
Abstract
The invention discloses a power grid interface conversion system, relates to the technical field of direct current power grids, and aims to solve the problem that an existing interface converter cannot bear larger voltage stress due to the adoption of a full-control device. The power grid interface conversion system comprises: the voltage balancer based on thyristors is arranged between the unipolar direct current power grid side and the true bipolar direct current power grid side, bipolar balance is achieved through a thyristor switch pair connected with the positive electrode and the negative electrode of the unipolar direct current power grid side, the thyristor switch pair comprises thyristors and parallel diodes, and the voltage balancer further comprises an energy transfer branch circuit for circuit balance and a supporting capacitor for supporting true bipolar voltage. The invention also discloses a control method of the power grid interface conversion system, which utilizes the volt-second balance principle to realize the self-balance of the voltages of the positive pole and the negative pole. The invention realizes the application of the converter under the medium-high voltage and large capacity by adopting the thyristor as a control device.
Description
Technical Field
The invention relates to the technical field of direct current power grids, in particular to a monopolar-to-true bipolar direct current power grid interface conversion system and a control method.
Background
In recent years, a large amount of fossil energy is excessively mined and consumed, and a series of problems such as energy shortage, climate warming, and atmospheric pollution are accompanying. In order to reduce the dependence on fossil energy, the related art of renewable energy has been rapidly developed. However, the conventional ac power grid is difficult to adapt to large-scale renewable energy grid connection, and a more reliable power grid architecture and corresponding electrical equipment need to be established to meet the power system mainly comprising new energy, and the dc power grid technology is one of effective technologies for solving the above problems.
The direct current power grid has a monopole wiring structure and a bipolar wiring structure, wherein the monopole wiring structure is of a two-wire structure and is divided into an anode direct current line and a cathode direct current line, the structure is simple and easy to control, but only a single direct current voltage level can be provided; the bipolar wiring structure is a three-wire structure and is divided into a positive direct current circuit, a negative direct current circuit and a neutral circuit, so that two voltage grades can be provided. Compared with a monopole wiring structure, the bipolar wiring structure can provide higher power supply reliability in both a high-voltage direct-current transmission system and a low-voltage direct-current power distribution system.
Considering economy and practicality, the current bipolar wiring structure adopts a monopolar-bipolar conversion device, and only needs to be embedded into the current monopolar system to realize a true bipolar structure, and the common monopolar-bipolar conversion device is a voltage balancer, so that energy transfer between two poles can be realized by utilizing the voltage balancer, and bipolar balance is further realized.
The conventional unipolar-to-true bipolar direct current system interface converter generally adopts a fully-controlled device, is limited by the withstand voltage of a power device and the serial connection technology of the device, cannot bear larger voltage stress, and is only suitable for low-voltage power distribution and utilization systems.
Disclosure of Invention
In order to overcome the defects of the prior art, one of the purposes of the invention is to provide a power grid interface conversion system which realizes the interface conversion from a unipolar to a true bipolar direct current system by adopting a thyristor as a control device.
One of the purposes of the invention is realized by adopting the following technical scheme:
the utility model provides a grid interface conversion system, includes the unipolar direct current electric wire netting side that links to each other with the direct current electric wire netting, the true bipolar direct current electric wire netting side that links to each other with true bipolar direct current electric wire netting, set up the voltage balancer based on the thyristor between unipolar direct current electric wire netting side and the true bipolar direct current electric wire netting side, the voltage balancer realizes bipolar balance through the thyristor switch pair that links to each other with the positive negative pole of unipolar direct current electric wire netting side, thyristor switch pair includes thyristor and parallelly connected diode, the voltage balancer still includes the energy transfer branch road that is used for circuit balance, the support electric capacity that is used for supporting true bipolar voltage.
Further, the monopolar direct current power grid side comprises a positive electrode and a negative electrode which are connected with a direct current power grid, and the true bipolar direct current power grid side comprises a positive electrode, a neutral line and a negative electrode.
Further, the energy transfer branch is located on the neutral line of the thyristor switch pair middle and the bipolar direct current power grid side, the energy transfer branch comprises a resonance branch and a balance branch, the resonance branch is used for generating double frequency resonance current and controlling the turn-off of the thyristor, the resonance branch comprises a resonance capacitor and a resonance inductor, the balance branch is used for providing a path for a direct current component and transferring unbalanced energy between the positive electrode and the negative electrode, and the balance branch comprises a resonance inductor and a balance inductor.
Further, the thyristor and the parallel diode are connected in series.
Further, the supporting capacitor comprises a positive-negative direct-current capacitor and is used for supporting the true bipolar voltage.
The second purpose of the invention is to provide a control method of the power grid interface conversion system, which adopts complementary switching control to the thyristor switch group so as to realize the self-balancing of the voltages of the positive pole and the negative pole.
The second purpose of the invention is realized by adopting the following technical scheme:
the control method of the power grid interface conversion system, the power grid interface conversion system is the power grid interface conversion system, the thyristor switch pair of the conversion system comprises a first thyristor switch and a second thyristor switch, and when the system operates, the first thyristor switch and the second thyristor switch are alternately triggered to be conducted, and the control method comprises the following steps:
a first thyristor of the first thyristor switch is triggered and conducted, and the first thyristor enters a first working mode;
when the first thyristor is turned off at zero current, a first diode connected in parallel in an opposite direction of the first thyristor switch is turned on, and the second thyristor switch enters a second working mode;
when the first diode is turned off at zero current, a second thyristor of the second thyristor switch is triggered to be conducted, and the third working mode is entered;
when the second thyristor is turned off with zero current, the second diode connected in reverse parallel of the second thyristor switch is turned on, and the fourth working mode is entered.
Further, the first thyristor of the first thyristor switch is triggered to be turned on, and enters a first working mode, including: the first thyristor, the energy transfer branch and the positive DC capacitor form a current loop, the current of the energy transfer branch is increased firstly and then gradually attenuated to zero, and when the current of the energy transfer branch is attenuated to zero, the first thyristor is turned off at zero current.
Further, when the first thyristor is turned off with zero current, the anti-parallel first diode of the first thyristor switch is turned on, and enters a second working mode, which comprises: the first diode, the energy transfer branch and the positive direct current capacitor form a current loop, the current of the energy transfer branch is increased negatively and then gradually decayed to zero, and when the current of the energy transfer branch decays to zero, the zero current of the first diode is turned off.
Further, when the first diode is turned off with zero current, the second thyristor of the second thyristor switch is triggered to be turned on, and enters a third working mode, which comprises: the second thyristor, the energy transfer branch and the negative direct current capacitor form a current loop, the current of the energy transfer branch is firstly increased negatively and then gradually attenuated to zero, and when the current of the energy transfer branch is attenuated to zero, the second thyristor is turned off at zero current.
Further, when the second thyristor is turned off with zero current, the anti-parallel second diode of the second thyristor switch is turned on, and enters a fourth working mode, including: the second diode, the energy transfer branch and the negative direct current capacitor form a current loop, the current of the energy transfer branch is increased firstly and then gradually attenuated to zero, and when the current of the energy transfer branch is attenuated to zero, the zero current of the second diode is turned off.
Compared with the prior art, the invention has the beneficial effects that:
the invention provides a power grid interface conversion system and a control method based on a thyristor, which adopt a half-control device of the thyristor to replace a full-control device, and have low cost and small loss; the semi-controlled devices are easy to be connected in series and voltage-equalizing, and the number of the devices can be flexibly adjusted to adapt to different voltage grades; the control method adopts fixed switch complementary control, can realize unbalanced energy transfer between dipoles, has self-balancing capability, has the characteristic of soft switching of all switching tubes in the whole process, has high balancing efficiency, and can realize the application of medium and high voltage and large capacity.
Drawings
FIG. 1 is a schematic diagram of a voltage balancer according to a first embodiment;
fig. 2 is a thyristor switch structure diagram of the first embodiment;
fig. 3 is a dc component equivalent circuit diagram of the second embodiment;
FIG. 4 is a diagram of a frequency-doubled AC component equivalent circuit in accordance with the second embodiment;
fig. 5 is a schematic diagram of equivalent structure of a thyristor-based unipolar-to-true bipolar dc system interface converter according to the second embodiment;
FIG. 6 is a schematic diagram of energy-specific branch current and voltage waveforms of embodiment two;
FIG. 7 is a schematic diagram of a mode one circuit of the second embodiment;
FIG. 8 is a schematic diagram of a second mode of embodiment;
fig. 9 is a schematic diagram of a mode three circuit of the second embodiment;
fig. 10 is a schematic diagram of a fourth mode circuit of the second embodiment;
FIG. 11 is a positive and negative voltage plot for example three;
fig. 12 is a positive and negative electrode transmission power graph of the third embodiment;
fig. 13 is a graph of the current of the energy transfer branch of embodiment three.
Detailed Description
The invention will now be described in more detail with reference to the accompanying drawings, to which it should be noted that the description is given below by way of illustration only and not by way of limitation. Various embodiments may be combined with one another to form further embodiments not shown in the following description.
Example 1
An embodiment provides a power grid interface conversion system, which aims to replace a traditional low-voltage device by using a thyristor as a control device so as to realize the application of medium-high voltage and large capacity.
Referring to fig. 1, the voltage balancer includes a unipolar dc power grid side 101 connected to a dc power grid, a bipolar dc power grid side 105 connected to a bipolar dc power grid, the voltage balancer realizes bipolar balancing by a thyristor switch pair 102 connected to the positive and negative poles of the unipolar dc power grid side 101, the thyristor switch pair 102 includes thyristors and parallel diodes, the voltage balancer further includes an energy transfer branch 103 for circuit balancing, and a supporting capacitor 104 for supporting the bipolar voltage.
The thyristor switch pair 102 is adopted to replace the traditional full-control device, so that the cost is saved, the loss is low, the half-control device is easy to realize series voltage equalizing, and the number of the devices can be flexibly adjusted to adapt to different voltage grades; the unbalanced energy transfer between the dipoles can be realized by adopting fixed switch complementary control, the self-balancing capacity is realized, all switching tubes have the characteristic of soft switching in the whole process, and the balancing efficiency is high.
The monopolar direct current power grid side 101 is provided with a positive line and a negative line, and is connected with a direct current power grid needing to be subjected to single-pole and double-pole conversion; a thyristor switch pair 102 is connected to the positive and negative poles of the unipolar dc grid side 101, the thyristor switch pair 102 comprising a set of thyristors T containing anti-parallel diodes 1 、T 2 The thyristor can use a single thyristor or a thyristor valve formed by connecting a plurality of thyristors in series, the energy transfer branch 103 is positioned in the middle of the thyristor switch pair 102 and on the neutral line of the bipolar direct current power grid side 105, the energy transfer branch 103 comprises a resonance branch and a balance branch, and the resonance branch is formed by a resonance capacitor C r And resonant inductance L r The composition is used for generating double frequency resonant current and is used for turning off the thyristor. The balance branch circuit consists of a resonance inductance and a balance inductance L b The composition is used for providing a path for the direct current component and transferring unbalanced energy between the anode and the cathode. The supporting capacitor comprises a positive-negative DC capacitor C p And C n A component for supporting a true bipolar voltage. The true bipolar DC grid side 105 includes three lines, positive, neutral, and negative, respectively, and a true bipolar grid V p And V n Are connected.
In this embodiment, referring to fig. 2, in order to adapt to the thyristor switch pairs 102 with different voltage classes, each device further includes a voltage equalizing branch consisting of a capacitor and a resistor, wherein the thyristor switch pairs are formed by serially connecting a plurality of thyristors and parallel diodes.
Example two
Embodiment two is a control method executed based on embodiment one.
The working principle of the thyristor-based voltage balancer comprises that complementary switching control is adopted for a thyristor switch group, and the self-balancing of voltages of positive and negative poles is realized by utilizing the volt-second balancing principle.
In operation, a current i flows through the energy transfer branch 103 r I.e. streamingVia inductance L r Is composed of two parts, namely a direct current component i flowing through a balance branch b And a double frequency alternating current component i flowing through the resonance capacitor Cr Referring to fig. 3 and 4, the circuit can be split into two current equivalent circuits.
With positive electrode transmission power P 1 Less than the negative electrode transmission power P 2 For the analysis, please refer to the equivalent circuit structure shown in fig. 5, wherein the consumed power is equivalent to the load and satisfies R p >R n . Under the working condition, dead zone influence is ignored, and the embodiment has four working modes. Namely:
a first thyristor of the first thyristor switch is triggered and conducted, and the first thyristor enters a first working mode;
when the first thyristor is turned off at zero current, a first diode connected in parallel in an opposite direction of the first thyristor switch is turned on, and the second thyristor switch enters a second working mode;
when the first diode is turned off at zero current, a second thyristor of the second thyristor switch is triggered to be conducted, and the third working mode is entered;
when the second thyristor is turned off with zero current, the second diode connected in reverse parallel of the second thyristor switch is turned on, and the fourth working mode is entered.
Specifically, referring to the current-voltage waveform shown in fig. 6, the thyristor T 1 And thyristor T 2 The switching frequency of the thyristor is twice the resonant frequency of the current of the resonant branch circuit according to the fixed switching frequency rotation triggering conduction.
Please refer to a schematic diagram of a mode one circuit shown in fig. 7, mode one [ t ] 0 -t 2 ]At t 0 At the moment, a first thyristor T 1 Triggering on via a first thyristor T 1 The energy transfer branch 103 and the positive DC capacitor form a current loop, and the energy transfer branch current i r Increasing from zero, the energy transfer branch current i r Increasing and then decaying to zero. At this time, the direct current component i b And a double frequency alternating current component i Cr All are positive, the positive DC capacitor releases energy, and the resonance capacitor voltage u cr Rising. At t 1 At the moment of time of day,the energy transfer branch 103 current is zero, the first thyristor T 1 The zero current is turned off.
Please refer to fig. 8, which shows a schematic diagram of a mode two circuit, mode two [ t ] 1 -t 2 ]At t 1 At moment, the resonant capacitor voltage is greater than the DC capacitor voltage, and the thyristor T 1 Inverse parallel first diode D 1 On, the first thyristor T1 is in an off state and passes through the first diode D 1 The energy transfer branch 103 and the positive DC capacitor form a current loop, and the energy transfer branch 103 has current i r Negative increases from zero, increases in reverse and then decays to zero. At this time, in the latter half resonance period, the frequency-doubled alternating current component i Cr Negative, direct current component i b Still positive, the positive DC capacitor absorbs energy and the resonant capacitor voltage decreases. At t 2 At time instant, the energy transfer branch 103 current i r Zero, first diode D 1 The zero current is turned off.
In the first half period, during the first mode and the second mode, the frequency doubling alternating current component transfers energy to zero in the whole resonance period, and the direct current component is always positive, so that the positive direct current capacitor releases energy, and the energy transfer branch absorbs energy.
Please refer to a schematic diagram of a modal three circuit shown in fig. 9, wherein the modal three [ t ] 2 -t 3 ]At t 2 At the moment, a second thyristor T 2 Triggering conduction through thyristor T 2 The energy transfer branch 103 and the negative DC capacitor form a current loop, and the current i of the energy transfer branch 103 r Negative increases from zero, increases in reverse and then decays to zero. At this time, the frequency-doubled alternating current component i Cr Negative, direct current component i b The direct current capacitor of the positive electrode and the negative electrode releases energy, the voltage of the resonance capacitor increases reversely, and at t 3 At time instant, the energy transfer branch 103 current i r Zero, the second thyristor T 2 The zero current is turned off.
Please refer to a schematic diagram of a fourth mode circuit shown in fig. 10, mode four [ t ] 3 -t 4 ]At t 3 At moment, the resonant capacitor voltage is greater than the negative DC capacitor voltage, and the second thyristor T 2 Anti-parallel second diode D 2 On, the second thyristor T2 is in an off state, and passes through the second diode D 2 The energy transfer branch 103 and the negative DC capacitor form a current loop, and the current of the energy transfer branch 103 increases positively from zero, and then decays to zero. At this time, the frequency doubling alternating current divides i Cr Positive, direct current component i b The positive and negative DC capacitors absorb energy. At t 4 At time instant, the energy transfer branch 103 current i r Zero, second diode D 2 The zero current is turned off.
In the second half period, in the third mode and the fourth mode, the alternating current component transfers energy to zero in the whole resonance period, and the direct current component is always positive, so that the positive direct current capacitor absorbs energy, and the energy transfer branch releases energy.
The balance inductor is connected in parallel with the positive electrode capacitor in the first half period, the negative electrode capacitor in parallel with the negative half period, and the direct current voltage of the positive electrode and the negative electrode can be automatically balanced according to the characteristic of volt-second balance of the inductor, so that other complicated control logic is not needed.
Example III
The third embodiment is a simulation experiment performed on the basis of the first embodiment and the second embodiment.
In this embodiment, a MATLAB/Simulink software simulation model is adopted, and simulation verification is performed on the topology structure of the first graph, and simulation parameters are shown in the following table 1:
table 1 simulation parameters
| Parameters (parameters) | Value of | Parameters (parameters) | Value of |
| Voltage (V) | ±10kV | Rated power | 1MW |
| Switching frequency | 800Hz | Resonant frequency | 1600Hz |
| Resonant inductor | 1mH | Resonant capacitor | 10uF |
| Balanced inductance | 10mH | DC capacitor | 1mF |
The given voltage class is + -10 kV; rated transmission power is 1MW, thyristor KK4500-40 (4 000V/4 500A) is adopted as simulation basis, switching frequency is set to 800Hz, resonant frequency is set to 1600Hz, positive and negative transmission power is 0.5MW at t=0s, the poles are symmetrical, positive transmission power is reduced to 1/2 of normal working condition at t=1s, positive transmission power is reduced to 1/3 of normal working condition at t=3s, and negative transmission power is always rated working condition. The simulation results are shown in FIGS. 11-13.
Referring to fig. 11 and 12, the voltages of the positive and negative electrodes and the corresponding transmission power curves, the positive electrode power is reduced to 1/2 of the normal working condition at t=1s, the positive electrode transmission power is reduced to 1/3 of the normal working condition at t=3s, and the voltages of the positive and negative electrodes can be stabilized at the rated voltage of 10kV under the condition of asymmetric transmission power.
Referring to fig. 13, before 1s, the transmission power of the two poles is equal, the dc component is zero, and no power is exchanged between the two poles; when t=1s, the positive electrode power is reduced to 1/2 of the normal working condition, when t=3s, the positive electrode transmission power is reduced to 1/3 of the normal working condition, the unbalanced power between the two electrodes is also gradually increased, and the direct current component is correspondingly increased.
The simulation result proves that the interface converter of the thyristor type unipolar-to-true bipolar direct current system has good dynamic performance, can autonomously and dynamically adjust the direct current component of the energy transfer branch, realizes the self-balancing of the voltage between the positive electrode and the negative electrode, and has the capability of realizing a true bipolar structure.
It will be apparent to those skilled in the art from this disclosure that various other changes and modifications can be made which are within the scope of the invention as defined in the appended claims.
Claims (10)
1. The utility model provides a grid interface conversion system, includes the unipolar direct current electric wire netting side that links to each other with the direct current electric wire netting, the true bipolar direct current electric wire netting side that links to each other with true bipolar direct current electric wire netting, its characterized in that, set up the voltage balancer based on the thyristor between unipolar direct current electric wire netting side and the true bipolar direct current electric wire netting side, the voltage balancer realizes bipolar balance through the thyristor switch pair that links to each other with the positive negative pole of unipolar direct current electric wire netting side, thyristor switch pair includes thyristor and parallelly connected diode, the voltage balancer still includes the energy transfer branch road that is used for circuit balance, is used for supporting the support electric capacity of true bipolar voltage.
2. The grid interface conversion system of claim 1, wherein the monopolar direct current grid side comprises a positive electrode connected to a direct current grid, and the true bipolar direct current grid side comprises a positive electrode, a neutral line, and a negative electrode.
3. The grid interface conversion system of claim 2, wherein the energy transfer branch is located on the neutral line of the thyristor switch pair at the middle and bipolar dc grid side, the energy transfer branch including a resonant branch for generating a doubled resonant current and controlling the turn-off of the thyristor and a balancing branch including a resonant capacitor and a resonant inductor, the balancing branch for providing a path for the dc component and transferring unbalanced energy between the positive and negative poles, the balancing branch including a resonant inductor and a balancing inductor.
4. The grid interface conversion system of claim 1, wherein the thyristor and the parallel diode are connected in series.
5. The grid interface conversion system of claim 2, wherein the support capacitor comprises an anode-cathode dc capacitor for supporting a true bipolar voltage.
6. A control method of a power grid interface conversion system, wherein the power grid interface conversion system is the power grid interface conversion system according to any one of claims 1 to 5, and a thyristor switch pair of the conversion system comprises a first thyristor switch and a second thyristor switch, and the control method is characterized in that when the system operates, the first thyristor switch and the second thyristor switch are alternately triggered and conducted, and the control method comprises the following steps:
a first thyristor of the first thyristor switch is triggered and conducted, and the first thyristor enters a first working mode;
when the first thyristor is turned off at zero current, a first diode connected in parallel in an opposite direction of the first thyristor switch is turned on, and the second thyristor switch enters a second working mode;
when the first diode is turned off at zero current, a second thyristor of the second thyristor switch is triggered to be conducted, and the third working mode is entered;
when the second thyristor is turned off with zero current, the second diode connected in reverse parallel of the second thyristor switch is turned on, and the fourth working mode is entered.
7. The method for controlling a power grid interface conversion system according to claim 6, wherein the first thyristor of the first thyristor switch is triggered to conduct and enters an operation mode one, comprising: the first thyristor, the energy transfer branch and the positive DC capacitor form a current loop, the current of the energy transfer branch is increased firstly and then gradually attenuated to zero, and when the current of the energy transfer branch is attenuated to zero, the first thyristor is turned off at zero current.
8. The method for controlling a power grid interface conversion system according to claim 6, wherein when the first thyristor is turned off at zero current, the anti-parallel first diode of the first thyristor switch is turned on, and the power grid interface conversion system enters a second operation mode, comprising: the first diode, the energy transfer branch and the positive direct current capacitor form a current loop, the current of the energy transfer branch is increased negatively and then gradually decayed to zero, and when the current of the energy transfer branch decays to zero, the zero current of the first diode is turned off.
9. The method for controlling a power grid interface conversion system according to claim 6, wherein when the first diode is turned off at zero current, the second thyristor of the second thyristor switch is triggered to be turned on, and enters a third working mode, comprising: the second thyristor, the energy transfer branch and the negative direct current capacitor form a current loop, the current of the energy transfer branch is firstly increased negatively and then gradually attenuated to zero, and when the current of the energy transfer branch is attenuated to zero, the second thyristor is turned off at zero current.
10. The method for controlling a power grid interface conversion system according to claim 6, wherein when the second thyristor is turned off at zero current, the anti-parallel second diode of the second thyristor switch is turned on, and enters a fourth operation mode, comprising: the second diode, the energy transfer branch and the negative direct current capacitor form a current loop, the current of the energy transfer branch is increased firstly and then gradually attenuated to zero, and when the current of the energy transfer branch is attenuated to zero, the zero current of the second diode is turned off.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311654673.4A CN117613841A (en) | 2023-12-05 | 2023-12-05 | Power grid interface conversion system and control method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311654673.4A CN117613841A (en) | 2023-12-05 | 2023-12-05 | Power grid interface conversion system and control method thereof |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN117613841A true CN117613841A (en) | 2024-02-27 |
Family
ID=89957799
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202311654673.4A Pending CN117613841A (en) | 2023-12-05 | 2023-12-05 | Power grid interface conversion system and control method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN117613841A (en) |
-
2023
- 2023-12-05 CN CN202311654673.4A patent/CN117613841A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN103986177B (en) | LCC-HVDC topological structure into which controllable sub-modules are connected in series | |
| CN108134384B (en) | Staggered connection soft switch hybrid multi-level direct current interconnected converter | |
| WO2020169018A1 (en) | Converter having multiple dc ports and control method | |
| CN110138005B (en) | Cascaded multi-mode photovoltaic grid-connected inverter and modulation method thereof | |
| CN106169885B (en) | A kind of switch of tandem type six multi-electrical level inverter | |
| CN106208396B (en) | A kind of distributing hybrid energy-storing based on MMC topology and electric power compensation system | |
| CN107769598A (en) | A kind of new Two-port netwerk half-bridge full-bridge mixing submodule MMC topologys | |
| CN109617445B (en) | DC side charging soft start circuit and method for five-level converter | |
| CN117674590A (en) | Direct-current boost converter and control method thereof | |
| CN111130323B (en) | IGBT series diode combined reverse resistance device series voltage-sharing circuit | |
| CN204669246U (en) | Modularization multi-level converter | |
| CN114553020B (en) | Capacitor multiplexing type modular multilevel converter and control method thereof | |
| CN203119788U (en) | Three-level inversion unit and photovoltaic inverter | |
| CN117613841A (en) | Power grid interface conversion system and control method thereof | |
| CN102420538A (en) | Diode clamping seven-level DC-AC (direct current and alternate current) transformation circuit | |
| CN116131325A (en) | Solid-state transformer for direct current collection and delivery of remote offshore wind farm | |
| CN109193722A (en) | In conjunction with the hybrid middle pressure AC network energy storage device of battery and super capacitor | |
| CN113258802B (en) | Submodule topological structure with direct-current fault clearing and self-voltage-equalizing capabilities | |
| CN205105115U (en) | Many level of modularization transverter and transverter module | |
| CN115276434A (en) | Electric energy router containing full-bridge submodule and control method thereof | |
| CN114400912A (en) | Potential induced degradation prevention circuit and photovoltaic system using same | |
| CN101867313B (en) | Cascade current converter | |
| CN108768184B (en) | Switch power unit and high-voltage direct-current circuit breaker | |
| CN203251237U (en) | Three-phase four-wire type three-level photovoltaic grid-connected inverter | |
| CN111355394A (en) | Series hybrid MMC topological structure suitable for flexible direct current transmission |
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 |