CN212086048U - High-level online energy-taking device for hybrid converter - Google Patents

Abstract

The utility model belongs to the direct current transmission field discloses an energy device is got on line to high position for mixing transverter, mixing transverter includes a plurality of bridge arms, each bridge arm includes that at least one can turn-off the pipe valve cluster and an at least thyristor valve cluster, each can turn-off the pipe valve cluster and include that at least one can turn-off the pipe, high position energy device electric connection is in can turning-off the pipe on line, when the bridge arm keeps shutting and tolerating direct current line voltage, can turn-off pipe valve cluster and thyristor valve cluster tolerate direct current voltage jointly, high position energy device is got on line and can be got the energy through the both ends that can turn-off the pipe, reach for control protection device can close the drive circuit power supply of pipe. The utility model discloses can be effectual for can turn off the energy supplies such as pipe drive circuit and control protection device of turn-off of the pipe valve cluster in the hybrid current converter, easily engineering realization.

Description

High-level online energy-taking device for hybrid converter

Technical Field

The utility model belongs to the direct current transmission field especially relates to a high-order online energy taking device for mixing transverter.

Background

The High-Voltage Direct Current (HVDC) technology utilizes stable Direct Current to have the advantages of no inductive reactance, no functional capacitive reactance, no synchronization problem and the like, and adopts High-power long-distance Direct Current transmission. The high-voltage direct-current transmission is a transmission mode that three-phase alternating current is rectified into direct current through a converter station and then transmitted to another converter station through a direct-current transmission line to be inverted into three-phase alternating current. It is basically composed of two converter stations and a dc transmission line, the two converter stations being connected to an ac system at both ends. An apparatus for a high voltage direct current transmission system comprising: the device comprises a current converter, a converter transformer, a smoothing reactor, an alternating current filter, a direct current lightning arrester, control protection equipment and the like. The converter is core equipment of high-voltage direct-current transmission and is a key factor influencing the performance, the operation mode, the equipment cost, the operation loss and the like of the HVDC system. The converter realizes the interconversion of direct current and alternating current, and is also called a rectifier (or an inverter) when the converter works in a rectification (or inversion) state. A converter system is generally composed of two or more converter bridges to realize the functions of alternating current to direct current and alternating current to current.

The high-voltage direct-current transmission technology is widely applied at present due to the advantages of large transmission capacity, low loss, high reliability and the like. And the failure of commutation is one of the faults with higher occurrence probability of the direct current transmission system. In the converter, the valve which is out of conduction can not restore the blocking capability within a period of time when the reverse voltage acts, or the phase change process is not completed during the reverse voltage, when the valve voltage changes to the positive direction, the phase of the valve which is out of conduction is changed to the original valve which is out of conduction, and the condition is called phase change failure. The converter valve is locked, the power transmission channel of a direct current system is interrupted, and the power grid can be broken down in severe cases.

The traditional high-voltage direct-current transmission converter adopts three-phase bridge rectification formed by thyristors as a basic unit, each bridge arm is formed by a thyristor valve string, and the thyristor valve string can not actively control current to be switched off, so that the converter has larger current conversion current and reactive support, the risk of phase change failure exists, and the reliability needs to be improved.

Referring to fig. 1, fig. 1 is a schematic diagram of a bridge arm of a novel high-voltage dc transmission hybrid converter. As shown in fig. 1, aiming at the problem of phase commutation failure occurring in the existing high-voltage dc transmission converter, the new type of hybrid high-voltage dc transmission converter can improve the capability of the converter to resist the phase commutation failure, thereby reducing the frequency of the phase commutation failure. The novel high-voltage direct-current transmission hybrid converter comprises a hybrid series connection of a thyristor and a turn-off pipe valve string.

When the novel high-voltage direct-current transmission hybrid converter operates, energy needs to be provided for device driving and the like of a pipe capable of being disconnected of a pipe valve string, and the energy is used for switching on and switching off and the like during each operation of the pipe valve string. The high-level online energy taking method only for the thyristor at present lacks the high-level online energy taking method for the interruptible tube of the interruptible tube valve string, so the utility model aims to provide a high-level online energy taking device applied to a novel high-voltage direct-current power transmission hybrid converter.

SUMMERY OF THE UTILITY MODEL

In view of the above problem, the utility model provides a high-order online power take-off device for mixing transverter, mixing transverter includes a plurality of bridge arms, each the bridge arm includes at least one can turn-off the pipe valve cluster and at least one thyristor valve cluster, each can turn-off the pipe valve cluster and include at least one can turn-off the pipe, wherein, high-order online power take-off device correspond ground electric property connect in can turn-off the pipe, work as the bridge arm keeps shutting and when enduring direct current line voltage, can turn-off the pipe valve cluster and the thyristor valve cluster tolerates direct current voltage jointly, high-order online power take-off device passes through can turn-off the both ends of pipe and get the ability, reach for control protection device can turn-off the drive circuit power supply of pipe.

The high-order online energy-taking device comprises an energy-taking unit, wherein the energy-taking unit is connected to two ends of the tube which can be closed, when the bridge arm keeps closed and endures direct-current line voltage, the tube valve string which can be closed and the thyristor valve string can endure direct-current voltage together, and the energy-taking unit can take energy through direct-current bus voltage at two ends of the tube which can be closed to supply power for a control protection device and a driving circuit of the tube which can be closed.

The high-order online energy-taking device comprises an energy-taking unit, the turn-off tube comprises a buffer capacitor, the energy-taking unit is connected to two ends of the buffer capacitor in parallel, when the bridge arm keeps locked and endures the voltage of a direct-current line, the turn-off tube valve string and the thyristor valve string endure the voltage of the direct current together, the buffer capacitor stores energy, and the energy-taking unit takes energy through the energy on the buffer capacitor to supply power for a control protection device and a driving circuit of the turn-off tube.

The above-mentioned high-order online can device of getting, wherein, still include:

the controllable power electronic switch and the current bleeder resistor are connected in parallel at two ends of the interruptible tube; and

and the control unit controls the controllable power electronic switch to be switched on or switched off according to the voltage at the two ends of the valve string, so that the voltage at the two ends of the valve string is controlled.

In the above high-level online energy-taking device, when the voltage across the valve string rises, the control unit controls the controllable power electronic switch to be closed, and the current-discharging resistor is switched on, so as to reduce the voltage across the valve string; when the voltage difference across the valve string decreases, the control unit controls the controllable power electronic switch to turn off, thereby increasing the voltage across the valve string.

The above high-order online energy-taking device, wherein the control unit comprises:

the voltage acquisition module is used for selecting the lowest voltage from the voltages at the two ends of the energy taking units;

the comparison module is used for obtaining a voltage difference value according to the lowest voltage and the voltages at the two ends of the energy taking unit;

and the control module controls the closing time of the controllable power electronic switch according to the voltage difference value.

The above high-order online energy-taking device, wherein the control unit further comprises:

and the duty ratio calculation module is used for obtaining the duty ratio of the controllable power electronic switch according to the voltage difference value, and the control module is used for controlling the closing time by controlling the duty ratio of the controllable power electronic switch.

In the above high-order online energy obtaining device, the duty ratio calculating module obtains the duty ratio of the controllable power electronic switch according to the following formula:

wherein D is_iIs the duty cycle of the switching action of the ith module, T is the action period of the controllable power electronic switch, K is the proportionality coefficient which influences the rate of reaching voltage balance, V_thIs the threshold voltage.

The above high-order online energy-taking device, wherein the control unit further comprises:

and the modulation module performs PWM modulation by taking the duty ratio of the controllable power electronic switch as a standard wave so as to output a control signal to the control module, and the control module controls the controllable power electronic switch to be switched on or switched off according to the control signal.

The high-order online energy-taking device for the hybrid converter is applied to a novel high-voltage direct-current transmission hybrid converter, can effectively supply energy to a pipe driving circuit capable of being cut off and a control protection device and the like of a pipe valve string capable of being cut off in the hybrid converter, and is easy to realize engineering; simultaneously because the utility model discloses technical scheme designs high-order online energy taking method, can effectively reduce the cost, reduce the loss, improve overall reliability etc to filled the present blank in this field, expected to obtain the engineering application in future mixed transverter.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

Drawings

In order to more clearly illustrate the embodiments of the present invention 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 described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

Fig. 1 is a schematic diagram of a bridge arm of a novel high-voltage direct-current transmission hybrid converter;

FIG. 2 is a schematic view of a first embodiment of a shut off tube;

fig. 3 is a schematic connection diagram of a first embodiment of the high-level online energy-taking device according to the present invention;

FIG. 4 is a schematic structural diagram of the high-level online energy-taking device in FIG. 3;

FIG. 5 is a schematic structural diagram of a control unit;

FIG. 6 is a schematic view of a second embodiment of a closable tube;

fig. 7 is a schematic connection diagram of a second embodiment of the high-level online energy-obtaining device of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the embodiments of the present invention are clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.

References to "a plurality" herein include "two" and "more than two".

As used herein, "connected" and "electrically connected" include direct connection between two components, and also include indirect connection between two components through other components or circuits.

The utility model aims at providing a but be applied to high-order online energy taking device of novel high-voltage direct-current transmission hybrid current converter's shutoff pipe. Aiming at the novel high-voltage direct-current transmission hybrid converter which is formed by mixing and connecting a thyristor and a turn-off pipe valve string in series and has been proposed at present, the turn-off pipe valve string is powered by adopting high-level online energy taking.

Referring to fig. 2, fig. 2 is a schematic view of a first embodiment of a turn-off pipe. As shown in fig. 2, the hybrid converter includes a plurality of bridge arms Ap, An, Bp, Bn, Cp, Cn, each of the bridge arms includes at least one turn-off pipe valve string and at least one thyristor valve string, each thyristor valve string is formed by connecting k thyristors S1-Sk in series, k is a positive integer greater than or equal to 1, each turn-off pipe valve string is formed by connecting m turn-off pipes Q1 … … Qm in series, and m is a positive integer greater than or equal to 1.

Referring to fig. 3, fig. 3 is a schematic connection diagram of a first embodiment of the high-level online energy-obtaining device of the present invention. As shown in fig. 3, the utility model discloses a high-order online energy taking device 1 correspond ground electric property connect in can turn-off the pipe, work as the bridge arm keeps shutting and when enduring direct current line voltage, can turn-off the pipe valve cluster and the thyristor valve cluster tolerates direct current voltage jointly, high-order online energy taking device 1 passes through can turn-off the both ends of pipe and get the energy, for control protection device 2 reaches can turn-off the drive circuit power supply of pipe.

Specifically, in this embodiment, since the two ends of the shutdown tube are not connected in parallel with the buffer capacitors, the high-level online energy-taking device is directly connected in parallel with the two ends of the shutdown tube, and the energy of the dc bus is used to supply energy to the shutdown tube. Specifically, when each bridge arm is kept locked, the bridge arm can bear direct-current line voltage, and the thyristor valve string and the pipe valve string which can be turned off can bear the direct-current voltage together, so that the direct-current bus voltage at the two ends of each turn-off pipe can be used for obtaining energy to supply power for a driving circuit of the turn-off pipe, a control protection system device such as a floor and the like.

Further, the high-order online energy-taking device 1 includes an energy-taking unit 11, the energy-taking unit 11 is connected in parallel to two ends of the tube capable of being turned off, when the bridge arm keeps locked and endures a dc line voltage, the tube valve string capable of being turned off and the thyristor valve string endure a dc voltage together, and the energy-taking unit 11 takes energy through a dc bus voltage at two ends of the tube capable of being turned off to supply power to a control protection device and a driving circuit of the tube capable of being turned off.

The turn-off transistor includes transistor devices such as an insulated gate bipolar transistor, a metal oxide semiconductor field effect transistor, an enhanced electron emission transistor and the like, and thyristor devices such as an integrated gate commutated thyristor and a gate turn-off thyristor and the like, and for the transistor devices, the collector and the emitter are provided; for thyristor-like devices, the anode and cathode are used.

In the embodiment, the energy obtaining unit 11 is a power module including a DC/DC, but the present invention is not limited thereto.

Referring to fig. 4, fig. 4 is a schematic structural diagram of the high-order online energy-taking device in fig. 3. As shown in fig. 4, the high-order online energy obtaining apparatus 1 further includes: a controllable power electronic switch M and a current leakage resistor Ri connected in parallel to both ends of the interruptible tube, and a control unit 12; the control unit 12 is electrically connected to each energy obtaining unit 11 and each controllable power electronic switch M, and the control unit 12 controls the controllable power electronic switch M to be turned on or off according to the voltages at the two ends of the valve string, so as to control the voltages at the two ends of the valve string. When the voltage at the two ends of the valve string rises, the control unit controls the controllable power electronic switch M to be closed, and the current discharge resistor Ri is switched on, so that the voltage at the two ends of the valve string is reduced; when the voltage difference across the valve string decreases, the control unit controls the controllable power electronic switch M to switch off, thereby increasing the voltage across the valve string.

Specifically, because the energy taking unit of the high-voltage online energy taking device is directly connected in parallel at two ends of the pipe capable of being closed, the static pressure equalizing effect of the pipe valve string capable of being closed is influenced. Therefore, the following power supply active voltage-sharing circuit and a certain control strategy are required to be adopted, the stability of the output voltage and the power of the high-voltage online energy-taking power supply module is ensured, and the static voltage-sharing effect between the valve string series devices is improved. Two ends of each interruptible tube are connected in parallel with a controllable power electronic switch M and a current leakage resistor Ri. The action of the electronic switch M is controlled by the voltage change of the two ends, namely when the voltage of the two ends of a certain series module is higher, the switch M is controlled to be closed, the resistor Ri is put into use, and redundant power is consumed, so that the equivalent voltage-sharing resistance of the module is reduced, and the voltage of the two ends of the module is reduced. When the voltage difference of a certain series module is reduced, the electronic switch M exits, unnecessary power consumption is reduced, and the equivalent voltage-sharing resistance of the module is increased, so that the voltage at two ends of the module is increased. Thereby ensuring the voltage-sharing characteristic of all the series modules.

Referring to fig. 5, fig. 5 is a schematic structural diagram of a control unit. As shown in fig. 5, the control unit 12 includes: a voltage acquisition module 121, a comparison module 122 and a control module 123; the voltage obtaining module 121 selects the lowest voltage from the voltages at the two ends of the plurality of energy obtaining units 11; the comparing module 122 obtains a voltage difference according to the lowest voltage and the voltages at the two ends of the energy obtaining unit 11; the control module 123 controls the closing time of the controllable power electronic switch M according to the voltage difference.

Wherein the control unit further comprises: the duty ratio calculating module 124 and the modulating module 125, the duty ratio calculating module 124 obtains the duty ratio of the controllable power electronic switch according to the voltage difference, and the control module 123 controls the on-time by controlling the duty ratio of the controllable power electronic switch; the modulation module 125 performs PWM modulation on the duty ratio of the controllable power electronic switch M as a standard wave, so as to output a control signal to the control module 123, and the control module 123 controls the controllable power electronic switch M to be turned on or off according to the control signal.

In this embodiment, the duty cycle calculation module 124 obtains the duty cycle of the controllable power electronic switch according to the following formula:

wherein D is_iIs the duty cycle of the switching action of the ith module, T is the action period of the controllable power electronic switch, K is the proportionality coefficient which influences the rate of reaching voltage balance, V_thIs the threshold voltage.

For example, the utility model discloses an adopt the voltage balance control strategy, specifically speaking, acquire the voltage V at each unit both ends of getting energy through voltage acquisition module 121₁，V₂...V_nAnd from voltage V₁，V₂...V_nTo select the lowest voltage V_minThe voltage V across each energy-taking unit is compared by the comparison module 122_iRespectively with the lowest voltage V_minBy contrast, the greater the voltage difference between them, the longer the switch M is closed, and the resistor R_iThe longer the time invested.

The duty cycle of the controllable power electronic switch M is obtained by the duty cycle calculation module 124, specifically, the duty cycle of the controllable power electronic switch M is recorded as D_iThe period of action of the switch M is T and the proportionality factor K, which affects the rate at which voltage equilibrium is reached. The logical expression of the control strategy can be obtained:

wherein D_iDuty ratio of switching action of i-th module, V_thIs a threshold voltage of V_th＝T_s/K_p+ V_min。

Finally, the modulation module 125 performs PWM modulation using the duty ratio as a standard wave and the triangular wave as a carrier, the finally output control signal only controls the module 123, and the control module 123 controls the on and off of the switch M in the corresponding ith high-voltage online energy-obtaining module according to the control signal.

Referring to fig. 6, fig. 6 is a schematic view of a second embodiment of a pipe capable of being closed. The closable pipe shown in fig. 6 is substantially the same as the closable pipe shown in fig. 2, and therefore the same parts will not be described herein again, and different parts will now be described below. In this embodiment, as shown in fig. 6, the turn-off pipe further includes a buffer capacitor C_sAnd a resistance R_sBuffer capacitor C_sAnd a resistor R_sThe resistors R are connected in parallel after being connected in series_pAt both ends of the same.

Referring to fig. 7, fig. 7 is a schematic connection diagram of a second embodiment of the high-level online energy-obtaining device of the present invention. As shown in fig. 7, the high-order online energy obtaining device 1 includes an energy obtaining unit 11, and the energy obtaining unit 11 is connected in parallel to the buffer capacitor C_sWhen the bridge arm is kept locked and endures the voltage of a direct current line, the tube valve string capable of being turned off and the thyristor valve string endure the voltage of the direct current together, and the buffer capacitor C_sEnergy is stored, and the energy taking unit 11 passes through the buffer capacitor C_sThe energy is taken to supply power for the control protection device 2 and the drive circuit of the interruptible tube.

It should be noted that, in the present invention, the control protection device 2 includes a floor, but the present invention is not limited thereto.

The utility model discloses still provide a high-order online method of getting energy for mixing transverter, mixing transverter includes a plurality of bridge arms, each the bridge arm includes that at least one can turn off the pipe valve cluster and at least a thyristor valve cluster, each can turn off the pipe valve cluster and include that at least one can turn off the pipe, a serial communication port, high-order online method of getting energy is applied to the high-order online device of getting energy among the aforesaid, high-order online method of getting energy in when the bridge arm keeps shutting and tolerates direct current line voltage, through can turn off the both ends of pipe and get energy, for control protection device reaches can turn off the drive circuit power supply of pipe.

The high-order online energy-taking device for the hybrid converter is applied to a novel high-voltage direct-current transmission hybrid converter, can effectively supply energy to a pipe driving circuit capable of being cut off and a control protection device and the like of a pipe valve string capable of being cut off in the hybrid converter, and is easy to realize engineering; simultaneously because the utility model discloses technical scheme designs high-order online energy taking method, can effectively reduce the cost, reduce the loss, improve overall reliability etc to filled the present blank in this field, expected to obtain the engineering application in future mixed transverter.

Although the present invention has been described in detail with reference to the foregoing embodiments, it should be understood by those skilled in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not depart from the spirit and scope of the present invention in its corresponding aspects.

Claims (9)

1. A high-level online energy-taking device for a hybrid converter, the hybrid converter comprises a plurality of bridge arms, each bridge arm comprises at least one tube valve string which can be turned off and at least one thyristor valve string, each tube valve string which can be turned off comprises at least one tube which can be turned off, the high-level online energy-taking device is correspondingly and electrically connected with the tube which can be turned off, when the bridge arms are kept locked and bear direct-current line voltage, the tube valve string which can be turned off and the thyristor valve string together bear the direct-current voltage, and the high-level online energy-taking device takes energy through two ends of the tube which can be turned off to supply power for a driving circuit which controls a protection device and the tube which can be turned off.

2. The high-order online energy-taking device according to claim 1, comprising an energy-taking unit, wherein the energy-taking unit is connected in parallel to two ends of the pipe capable of being turned off, when the bridge arm keeps locked and endures a dc line voltage, the pipe valve string capable of being turned off and the thyristor valve string endure a dc voltage together, and the energy-taking unit takes energy through a dc bus voltage at two ends of the pipe capable of being turned off to supply power to a control protection device and a driving circuit of the pipe capable of being turned off.

3. The high-order online energy taking device according to claim 1, comprising an energy taking unit, wherein the turn-off tube comprises a buffer capacitor, the energy taking unit is connected in parallel to two ends of the buffer capacitor, when the bridge arm remains locked and endures a dc line voltage, the turn-off tube valve string and the thyristor valve string endure a dc voltage together, the buffer capacitor stores energy, and the energy taking unit takes energy through energy on the buffer capacitor to supply power to a driving circuit for controlling the protection device and the turn-off tube.

4. The high-order online energy-taking device according to claim 2, further comprising:

the controllable power electronic switch and the current bleeder resistor are connected in parallel at two ends of the interruptible tube; and

and the control unit controls the controllable power electronic switch to be switched on or switched off according to the voltage at the two ends of the valve string, so that the voltage at the two ends of the valve string is controlled.

5. The high-order online energy-taking device according to claim 4, wherein when the voltage across the valve string increases, the control unit controls the controllable power electronic switch to close, and the current-discharging resistor is switched on, so as to reduce the voltage across the valve string; when the voltage difference across the valve string decreases, the control unit controls the controllable power electronic switch to turn off, thereby increasing the voltage across the valve string.

6. The high-order online energy-taking device according to claim 4 or 5, wherein the control unit comprises:

the voltage acquisition module is used for selecting the lowest voltage from the voltages at the two ends of the energy taking units;

the comparison module is used for obtaining a voltage difference value according to the lowest voltage and the voltages at the two ends of the energy taking unit;

and the control module controls the closing time of the controllable power electronic switch according to the voltage difference value.

7. The high-order online energy-taking device according to claim 6, wherein the control unit further comprises:

and the duty ratio calculation module is used for obtaining the duty ratio of the controllable power electronic switch according to the voltage difference value, and the control module is used for controlling the closing time by controlling the duty ratio of the controllable power electronic switch.

8. The high-order online energy-taking device according to claim 7, wherein the duty cycle calculating module obtains the duty cycle of the controllable power electronic switch according to the following formula:

wherein D is_iIs the duty cycle of the switching action of the ith module, T is the action period of the controllable power electronic switch, K is the proportionality coefficient which influences the rate of reaching voltage balance, V_thIs the threshold voltage.

9. The high-order online energy-taking device according to claim 6, wherein the control unit further comprises:

and the modulation module performs PWM modulation by taking the duty ratio of the controllable power electronic switch as a standard wave so as to output a control signal to the control module, and the control module controls the controllable power electronic switch to be switched on or switched off according to the control signal.

Images