Fully-controlled converter valve module, fully-controlled static frequency converter, fully-controlled static frequency converter system and control method

Abstract

The invention discloses a full-control type converter valve module, a full-control type static frequency converter, a system and a control method, and relates to the technical field of pumped storage. Each sub-bridge arm comprises at least one integrated gate commutated thyristor unit; the integrated gate commutation thyristor unit comprises an integrated gate commutation thyristor, a dynamic voltage-sharing branch circuit used for AC voltage sharing, a static voltage-sharing branch circuit used for DC voltage sharing, and an integrated controller used for controlling on or off of the integrated gate commutation thyristor. Wherein the anode of the integrated gate commutated thyristor is respectively connected with one end of the dynamic voltage-sharing branch and one end of the static voltage-sharing branch, the other end of the dynamic voltage-sharing branch is connected with the integrated controller, and the cathode of the integrated gate commutated thyristor is respectively connected with the other end of the static voltage-sharing branch and the integrated controller. The problem of small-angle commutation failure of the converter valve can be solved.

Description

Technical Field

[0001] The present application relates to the field of pumped storage technology, and in particular to a fully-controlled converter valve module, a fully-controlled static frequency converter, a system and a control method. Background Art

[0002] Static frequency converters are the main starting equipment for large pumped storage power station units when they operate as pumped motors. Their safe and stable operation is crucial to the normal production of the entire pumped storage power station.

[0003] In related technologies, semi-controlled semiconductor devices are generally used to construct the converter valve module in the static inverter. However, the converter valve module of the semi-controlled semiconductor device is very prone to commutation failure at a small trigger angle and can only achieve commutation at a relatively large trigger angle, which increases the loss of the equipment. Summary of the Invention

[0004] The main purpose of the present application is to provide a fully controlled converter valve module, a fully controlled static frequency converter, a system and a control method, aiming to solve the technical problem in the related art that the converter valve is prone to commutation failure at a small trigger angle.

[0005] To achieve the above objectives, the present application proposes a fully controlled converter valve module, which includes a three-phase bridge arm circuit; each sub-bridge arm of the three-phase bridge arm circuit includes at least one integrated gate-commutated thyristor unit; the integrated gate-commutated thyristor unit includes: integrated gate-commutated thyristors; Dynamic voltage balancing branch, used for AC voltage balancing of integrated gate-commutated thyristors; Static voltage balancing branch, used for DC voltage balancing of integrated gate-commutated thyristors; An integrated controller for controlling the on / off of the integrated gate-commutated thyristors; Among them, the anode of the integrated gate-commutated thyristor is respectively connected to one end of the dynamic voltage-sharing branch and one end of the static voltage-sharing branch, the other end of the dynamic voltage-sharing branch is connected to the integrated controller, and the cathode of the integrated gate-commutated thyristor is respectively connected to the other end of the static voltage-sharing branch and the integrated controller.

[0006] In one embodiment, each sub-bridge arm of the three-phase bridge arm circuit includes at least two integrated gate-commutated thyristor units connected in series.

[0007] In one embodiment, the dynamic voltage balancing branch includes a first resistor and a capacitor; One end of the first resistor is connected to the anode of the integrated gate-commutated thyristor, and the other end of the first resistor is connected to the integrated controller via a capacitor.

[0008] In one embodiment, the static voltage balancing branch includes a second resistor; the second resistor is connected in parallel to the anode and cathode of the integrated gate-commutated thyristor.

[0009] In addition, to achieve the above-mentioned purpose, the present application also proposes a fully-controlled static inverter, which includes a rectifier-side fully-controlled converter valve, a smoothing reactor, and an inverter-side fully-controlled converter valve connected in sequence; Among them, the rectifier-side fully-controlled converter valve and the inverter-side fully-controlled converter valve each include at least one cascaded fully-controlled converter valve module as described above.

[0010] In one embodiment, the rectifier-side fully-controlled converter valve includes two cascaded fully-controlled converter valve modules; The inverter-side fully-controlled converter valve includes a fully-controlled converter valve module, or the inverter-side fully-controlled converter valve includes two cascaded fully-controlled converter valve modules.

[0011] In one embodiment, the fully controlled static frequency converter further includes: Multiple groups of lightning arresters; each group of lightning arresters is set corresponding to each fully-controlled converter valve module, and the lightning arresters are used to provide overvoltage protection for the fully-controlled converter valve modules.

[0012] In one embodiment, the fully controlled static frequency converter further includes: Multiple groups of magnetic rings; each group of magnetic rings is set corresponding to each fully-controlled converter valve module, and the magnetic rings are used to suppress sudden changes in the AC side current of the fully-controlled converter valve module.

[0013] In addition, to achieve the above objectives, the present application also proposes a power transmission system, which includes: rectifier transformer; Inverter transformer; Such as the fully controlled static inverter mentioned above; The rectifier transformer is connected to the rectifier-side fully-controlled converter valve of the fully-controlled static frequency converter, and the inverter transformer is connected to the inverter-side fully-controlled converter valve of the fully-controlled static frequency converter.

[0014] In addition, to achieve the above-mentioned purpose, the present application also proposes a control method for a fully-controlled static frequency converter, which can be used in a fully-controlled static frequency converter control system, wherein the fully-controlled static frequency converter control system is connected to the above-mentioned fully-controlled static frequency converter; The full-control static inverter control method includes: Generate grid synchronization signal; Generate valve base trigger signal based on grid synchronization signal; A valve base trigger signal is sent to the fully controlled static inverter, so that the integrated controller of each integrated gate commutated thyristor unit in the fully controlled static inverter controls the opening or closing of the corresponding integrated gate commutated thyristor based on the valve base trigger signal.

[0015] One or more technical solutions proposed in this application have at least the following technical effects: The present application proposes a fully controlled converter valve module, which includes a three-phase bridge arm circuit; each sub-bridge arm of the three-phase bridge arm circuit includes at least one integrated gate-commutated thyristor unit; the integrated gate-commutated thyristor unit includes an integrated gate-commutated thyristor, a dynamic voltage-sharing branch, a static voltage-sharing branch, and an integrated controller. Compared to a fully controlled converter valve module composed of semi-controlled devices, the integrated gate-commutated thyristor can not only be controllably turned on, but also controlled off. Its full controllability enables precise turning on and off at extremely small trigger angles, thereby achieving small trigger angle commutation; in addition, the dynamic voltage-sharing branch can achieve voltage balancing on the AC side, ensuring that the integrated gate-commutated thyristor maintains a stable voltage environment during operation, which helps to reduce commutation problems caused by voltage fluctuations; the static voltage-sharing branch reduces DC voltage fluctuations by voltage-sharing the DC voltage, further ensuring the stable operation of the fully controlled converter valve module. Therefore, the fully controlled converter valve module of the present application can achieve stable commutation at a small trigger angle. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following briefly introduces the drawings required for use in the embodiments or related technical descriptions. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.

[0018] Figure 1 This is a schematic diagram of the sub-bridge arm topology structure in the first embodiment of the fully controlled converter valve module of this application; Figure 2 This is a topological diagram of the power transmission system consisting of a 12-6 pulse fully controlled static inverter; Figure 3 This is a topological diagram of a power transmission system consisting of a 12-12 pulse fully controlled static inverter; Figure 4 Schematic diagram of the flow of the control method of the fully controlled static frequency converter in the embodiment of the present application; Figure 5 This is a schematic diagram of the control waveform of a fully controlled static inverter.

[0019] The realization of the objectives, functional features and advantages of this application will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0020] The following will be combined with the accompanying drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.

[0021] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back, etc.), such directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture. If the specific posture changes, the directional indication will also change accordingly.

[0022] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features limited to "first" and "second" may explicitly or implicitly include at least one of such features. In addition, if "and / or" or "and / or" appears in the full text, its meaning includes three parallel schemes. Taking "A and / or B" as an example, it includes scheme A, or scheme B, or a scheme in which A and B are satisfied at the same time. In addition, the technical solutions between the various embodiments can be combined with each other, but it must be based on the ability of ordinary technicians in this field to implement it. When the combination of technical solutions is mutually contradictory or cannot be implemented, it should be deemed that such a combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0023] Static frequency converters are the main starting equipment for large pumped storage power station units when they operate as pumped motors. Their safe and stable operation is crucial to the normal production of the entire pumped storage power station.

[0024] In related technologies, semi-controlled semiconductor devices are generally used to construct the converter valve module in the static inverter. However, the converter valve module of the semi-controlled semiconductor device is very prone to commutation failure at a small trigger angle and can only achieve commutation at a relatively large trigger angle, which increases the loss of the equipment.

[0025] To address the aforementioned issues, the present application proposes a fully-controlled converter valve module, which may include a three-phase bridge arm circuit; each sub-bridge arm of the three-phase bridge arm circuit includes at least one integrated gate-commutated thyristor unit. Specifically, each sub-bridge arm of the three-phase bridge arm circuit may include only one integrated gate-commutated thyristor unit; or each sub-bridge arm of the three-phase bridge arm circuit may include at least two integrated gate-commutated thyristor units connected in series. In practical applications, the number of integrated gate-commutated thyristor units in each sub-bridge arm can be determined based on the voltage requirement of the fully-controlled converter valve module. The higher the voltage requirement, the greater the number of integrated gate-commutated thyristor units provided.

[0026] See also Figure 1 , Figure 1 This is a schematic diagram of the sub-bridge arm topology structure in the first embodiment of the fully controlled converter valve module provided in this application. Figure 1 As shown, the sub-bridge arm includes at least one integrated gate-commutated thyristor unit ( Figure 1 In the figure, N (N≥2) series-connected integrated gate-commutated thyristor units are used as an example for illustration); the integrated gate-commutated thyristor unit may include an integrated gate-commutated thyristor (IGCT), a dynamic voltage balancing branch, a static voltage balancing branch, and an integrated controller.

[0027] Among them, the anode of IGCT is connected to one end of the dynamic voltage balancing branch and one end of the static voltage balancing branch respectively, the other end of the dynamic voltage balancing branch is connected to the integrated controller, and the cathode of IGCT is connected to the other end of the static voltage balancing branch and the integrated controller respectively.

[0028] The integrated controller is used to control the switching of the integrated gate-commutated thyristors (SCRs). In valve control, for example, a fully controlled static inverter (SVC) consisting of fully controlled valve modules typically uses a higher-level control and protection unit (CCP) to detect changes in grid-side voltage and phase, generating a carrier phase tracking (CPT) synchronization signal. Phase-locked loop (PLL) technology can be used during the control process to track the grid phase in real time and dynamically adjust the triggering timing of the CPT signal to ensure strict synchronization between the integrated gate-commutated thyristors (SCRs) in the fully controlled valve modules and the grid. Dynamic adjustment of the CPT signal through PLL technology can accommodate frequency adjustments across the full range of 0-60 Hz.

[0029] The CCP then transmits the CPT signal to the valve base electronics (VBE), the control unit of the commutator valve. The VBE generates valve base trigger signals based on the received CPT signal. These signals include a turn-on pulse signal to control the opening of a sub-bridge arm and a turn-off pulse signal to control the closing of a sub-bridge arm. The VBE transmits the generated turn-on and turn-off pulse signals to the integrated controller of each integrated gate-commutated thyristor (SCR) in the sub-bridge arm. The integrated controller is typically a thyristor protection unit (TPU). Upon receiving the turn-on or turn-off pulse signal from the VBE, the TPU sends a gate control signal to the gate of the corresponding IGCT to control the IGCT's conduction or shutdown. The gate control signal corresponding to the turn-on pulse signal triggers the IGCT to conduct, while the gate control signal corresponding to the turn-off pulse signal causes the IGCT to actively shut down before the current crosses zero, ensuring successful commutation at small turn-off angles.

[0030] Since IGCT can not only be turned on but also turned off in a controlled manner, its full controllability allows it to be forced to shut down through gate control signals at extremely small trigger angles without relying on grid voltage or current zero crossing, thus breaking free from the constraints of commutation voltage and completing commutation at small trigger angles.

[0031] In addition, the integrated controller can also collect the voltage across the IGCT and generate a forward voltage reporting signal based on the collected voltage status. This forward voltage reporting signal is in high-level form, used to indicate that the IGCT can currently withstand pressure and can operate normally. The integrated controller feeds the forward voltage reporting signal back to VBE. When VBE receives the high-level forward voltage reporting signal, it normally sends the valve base trigger signal to the integrated controller to control the conduction or shutdown of the IGCT. If VBE does not receive the forward pressure reporting signal fed back by the integrated controller, it indicates that the IGCT is currently unable to withstand pressure. At this time, the IGCT can be directly controlled to shut down to avoid device damage.

[0032] It should be noted that the above-mentioned IGCT can specifically adopt domestically produced reverse resistance IGCT devices, avoiding the problems of high construction cost and limited supply caused by excessive reliance on imported devices.

[0033] The dynamic voltage balancing branch is mainly used to balance the AC voltage of IGCT. When AC voltage is applied to both ends of the sub-bridge arm, the dynamic voltage balancing branch can make the AC voltage at both ends of each IGCT in the sub-bridge arm basically consistent. Under normal circumstances, the AC voltage inconsistency at both ends of each IGCT meets the technical specification of less than ±5%. Figure 1As shown, the dynamic voltage balancing branch may include a first resistor R and a capacitor C; one end of the first resistor R is connected to the anode of the integrated gate-commutated thyristor IGCT, and the other end of the first resistor R is connected to the integrated controller through the capacitor C.

[0034] It is understood that in the dynamic voltage-sharing branch of the above structure, the excess voltage across the IGCT can be stored in capacitor C through the charging and discharging action of the first resistor R and capacitor C, thereby achieving dynamic voltage balancing for the IGCT. In addition, the integrated controller can also draw energy from the capacitor of the dynamic voltage-sharing branch to provide its own operating power supply, thereby eliminating the need for an independent power supply module and reducing the size and design cost of the integrated gate-commutated thyristor unit.

[0035] The static voltage balancing branch is mainly used to balance the DC voltage of IGCT. When a DC voltage is applied to both ends of the sub-bridge arm, the DC voltage at both ends of each IGCT in the sub-bridge arm can be kept consistent through the static voltage balancing branch. Under normal circumstances, the DC voltage inconsistency at both ends of each IGCT meets the technical specification of less than ±5%. Figure 1 As shown, the static voltage balancing branch may include a second resistor Rd; the second resistor Rd is connected in parallel to the anode and cathode of the IGCT. The second resistor Rd connected in parallel to the two ends of the IGCT can play a voltage dividing role, thereby achieving static voltage balancing of the IGCT.

[0036] As can be understood, in the fully-controlled converter valve module provided by the embodiments of the present application, the integrated gate-commutated thyristors are not only controllably switched on but also controlled off. Their full controllability enables precise switching at extremely small trigger angles, thereby achieving commutation at small trigger angles. Furthermore, the dynamic voltage-sharing branch achieves voltage balancing on the AC side, ensuring that the integrated gate-commutated thyristors maintain a stable voltage environment during operation, helping to reduce commutation issues caused by voltage fluctuations. The static voltage-sharing branch reduces DC voltage fluctuations by balancing the DC voltage, further ensuring stable operation of the fully-controlled converter valve module. Thus, the fully-controlled converter valve module of this embodiment can achieve stable commutation at small trigger angles.

[0037] Furthermore, the present application also proposes a power transmission system, which may include a rectifier transformer 2, an inverter transformer 3, and a fully controlled static frequency converter 1. Figure 2 and Figure 3 As shown, the rectifier transformer 2 is connected to the rectifier-side fully-controlled converter valve 11 of the fully-controlled static inverter 1 , and the inverter transformer 3 is connected to the inverter-side fully-controlled converter valve 12 of the fully-controlled static inverter 1 .

[0038] The fully-controlled static inverter 1 may include a rectifier-side fully-controlled converter valve 11 , a smoothing reactor L, and an inverter-side fully-controlled converter valve 12 connected in sequence.

[0039] The rectifier-side fully-controlled converter valve 11 and the inverter-side fully-controlled converter valve 12 each include at least one cascaded fully-controlled converter valve module A, such as that described in the aforementioned embodiment. The fully-controlled converter valve module may include a three-phase bridge arm circuit; the three-phase bridge arm circuit includes six sub-bridge arms Aa. The specific structure of the fully-controlled converter valve module can be described with reference to the aforementioned embodiment. Since the fully-controlled static inverter of this application utilizes all the technical solutions of all the aforementioned embodiments, it at least possesses all the beneficial effects brought about by the technical solutions of the aforementioned embodiments, and therefore will not be further elaborated upon here.

[0040] The rectifier-side fully-controlled converter valve 11 can rectify AC current to convert it into DC current, and the smoothing reactor L can smooth the DC current to suppress high-frequency harmonic interference in the DC current. The inverter-side fully-controlled converter valve 12 converts DC current into AC current. The fully-controlled static inverter 1 thus constructed can achieve efficient "AC-DC-AC" energy conversion. The rectifier-side fully-controlled converter valve 11 and the inverter-side fully-controlled converter valve 12 each include at least one cascaded fully-controlled converter valve module 110. Multiple fully-controlled converter valve modules are connected in a cascade manner to ensure higher power carrying capacity. The specific number of cascades can be flexibly configured according to actual needs to improve the scalability and adaptability of the fully-controlled static inverter.

[0041] In one embodiment, the rectifier-side fully-controlled converter valve 11 may include two cascaded fully-controlled converter valve modules; the inverter-side fully-controlled converter valve 12 may include one fully-controlled converter valve module, thereby obtaining a 12-6 pulse fully-controlled static inverter. Figure 2 As shown, Figure 2 This is a topological diagram of the power transmission system consisting of a 12-6 pulse fully controlled static inverter; Figure 2 The fully-controlled converter valves on the inverter side of the fully-controlled static inverter shown are composed of a single set of fully-controlled converter valve modules. The two cascaded fully-controlled converter valve modules in the rectifier-side fully-controlled converter valves achieve higher voltage and current capacity, meeting the high-voltage and high-current rectification requirements and making them suitable for high-voltage power transmission. The use of a single set of fully-controlled converter valve modules on the inverter side simplifies the inverter-side circuit structure and reduces the complexity and cost of the fully-controlled static inverter. The 12-6-pulse fully-controlled static inverter can be used in scenarios requiring high-voltage, high-current rectification but relatively low inversion requirements, such as pumped-storage power plants and industrial motor starting.

[0042] Alternatively, the rectifier-side fully-controlled converter valve 11 may include two cascaded fully-controlled converter valve modules A; the inverter-side fully-controlled converter valve 12 may include two cascaded fully-controlled converter valve modules A, thereby obtaining the following: Figure 3The power transmission system shown is composed of a 12-12 pulse fully controlled static inverter. The inverter-side fully controlled converter valve 12 uses two cascaded fully controlled converter valve modules to provide higher system capacity and is suitable for applications requiring high power output. Furthermore, the use of two cascaded modules in both the rectifier-side fully controlled converter valve 11 and the inverter-side fully controlled converter valve 12 also provides a redundant design, which can enhance the reliability of the fully controlled static inverter 1. Even if a fully controlled converter valve module in the converter valve fails, the fully controlled static inverter can continue to operate, reducing downtime. The 12-12 pulse fully controlled static inverter can be used in scenarios requiring high voltage, high current rectification and inversion, such as large pumped storage power stations, large industrial motor starting, and high voltage direct current transmission systems.

[0043] The above-mentioned fully controlled static frequency converter may also include multiple groups of lightning arresters; each group of lightning arresters is set corresponding to each fully controlled converter valve module. The lightning arrester is mainly used to provide overvoltage protection for the fully controlled converter valve module. When the bridge arm part of the fully controlled converter valve module has an overvoltage, the overvoltage can be suppressed to ensure that the fully controlled converter valve module does not break down due to overvoltage. Figure 2 and Figure 3 As shown, a group of lightning arresters includes three lightning arresters 13, which are respectively installed between the AC bus phases (AB, BC, AC) of the fully controlled converter valve module to suppress phase-to-phase overvoltages, such as switching overvoltages, lightning-induced surges, etc.

[0044] The fully controlled static inverter can also include multiple groups of magnetic rings; each group of magnetic rings is set corresponding to each fully controlled converter valve module, and the magnetic rings are used to suppress the sudden change of the AC side current of the fully controlled converter valve module. When the current in the AC bus changes, the magnetic rings can generate a reverse voltage through electromagnetic induction. The greater the di / dt (i.e., the rate of change of current) of the AC bus, the higher the corresponding reverse voltage. This can suppress the rate of increase of the current and protect the bridge arm part of the fully controlled converter valve module from being damaged by the excessively high di / dt at the opening moment. Figure 2 and Figure 3 As shown, the number of magnetic rings in a group is three, and the three magnetic rings 14 are respectively arranged on the three-phase AC busbar of the fully controlled converter valve module to suppress the sudden change of current on each phase AC busbar.

[0045] In the above-mentioned transmission system, the rectifier-side fully-controlled converter valves and the inverter-side fully-controlled converter valves are connected to the AC system via corresponding rectifier and inverter transformers, respectively. The rectifier transformer converts the grid voltage (e.g., 10kV / 35kV) to a lower voltage based on the input requirements of the rectifier-side fully-controlled converter valves, while also increasing the current capacity to meet the requirements of high-power DC loads. It also isolates the AC / DC systems, preventing reverse DC intrusion into the grid and protecting AC-side equipment (such as generators) from DC bias. The inverter transformer boosts the low-voltage AC output of the inverter-side converter valves to the high-voltage level required by the grid or load. Similar to the rectifier transformer, it also isolates the inverter-side fully-controlled converter valves from the grid / load, preventing reverse DC intrusion or fault current, and protecting the switching components of the inverter-side fully-controlled converter valves.

[0046] As will be appreciated, the power transmission system and fully-controlled static inverter provided in this embodiment utilize the fully-controllable, fully-controlled converter valve module described in the aforementioned embodiment, enabling both controlled opening and controlled closing of the converter valves in the fully-controlled static inverter in the power transmission system. Furthermore, during the energy conversion process in the fully-controlled static inverter, the IGCTs in the rectifier-side fully-controlled converter valves and the inverter-side fully-controlled converter valves can be controlled to be closed, thereby preventing commutation failure on the inverter side of the fully-controlled static inverter.

[0047] Furthermore, the present application also proposes a fully controlled static inverter control method, which can be used in a fully controlled static inverter control system. The fully controlled static inverter control system is connected to the aforementioned fully controlled static inverter. Figure 4 , Figure 4 The figure shows a flow chart of the control method of the fully controlled static frequency converter of the present application.

[0048] In this embodiment, the control method of a fully controlled static inverter may include steps S100 to S300: Step S100: Generate a power grid synchronization signal.

[0049] Step S200: Generate a valve base trigger signal based on a power grid synchronization signal.

[0050] Step S300 : sending a valve base trigger signal to the fully controlled static inverter, so that the integrated controller of each integrated gate-commutated thyristor unit in the fully controlled static inverter controls the opening or closing of the corresponding integrated gate-commutated thyristor based on the valve base trigger signal.

[0051] Specifically, the fully controlled static inverter control system can include the upper control and protection unit CCP and the valve base electronic device VBE. Figure 5 The control waveform diagram of the fully controlled static inverter is shown in FIG. Figure 5 middle ua(t) 、 ub (t) and uc(t) is the three-phase voltage on the AC side, i(t) is the current flowing through a certain sub-bridge arm Q1, u(t) is the voltage across the sub-bridge arm Q1. The CCP generates a grid synchronization signal (CPT_RI) based on monitored grid phase changes. The CCP sends this grid synchronization signal to the VBE, which generates a valve base trigger signal based on CPT_RI. The valve base trigger signal includes a turn-on pulse signal command (FP) and a turn-off pulse signal command (FP_OFF). The VBE sends the generated FP and FP_OFF ​​to the integrated controller (TPU) corresponding to each integrated gate-commutated thyristor unit in the fully controlled static inverter. The TPU controls the turning on or off of the IGCT according to the corresponding command.

[0052] like Figure 5 As shown, α The corresponding angle is the trigger angle, and time t1 is the trigger start time. At this time, TPU can collect the voltage across the IGCT to determine whether the current IGCT can withstand the pressure. If it can withstand the pressure, it will generate a forward voltage reporting signal IP and feed the IP signal back to VBE. At the same time, CCP generates a CPT_RI signal and sends it to VBE. VBE generates an opening pulse signal instruction FP at time t2 based on the received CPT_RI signal. VBE receives the aforementioned IP signal, so it can perform IGCT conduction control normally and send the FP signal to TPU. At this time, all IGCTs in the sub-bridge arm Q1 are turned on. Phase switching begins at time T3, and μ is the phase switching angle. The current on the sub-bridge arm Q1 i(t) VBE can generate a turn-off pulse signal instruction FP_OFF ​​before the commutation moment corresponding to time t4 to forcibly turn off the IGCT of the sub-bridge arm Q1 to avoid commutation failure. At this time, the turn-off angle is γ.

[0053] Since the IGCT in the fully controlled static inverter can not only be turned on but also turned off in a controlled manner, its full controllability enables the IGCT to be forced to shut down through the shutdown pulse signal at an extremely small trigger angle to completely shut down the corresponding sub-bridge arm without relying on the grid voltage or current zero crossing. It only needs to automatically generate the valve base trigger signal through the grid synchronization signal to control the forced shutdown of the IGCT, thereby getting rid of the constraints of the commutation voltage and completing the commutation at a small trigger angle.

[0054] The above descriptions are only some embodiments of the present application and do not limit the scope of protection. All equivalent structural transformations made using the contents of the present application specification and drawings under the technical concept of the present application, or direct / indirect application in other related technical fields are included in the scope of protection.

Claims

1. A fully controlled converter valve module, characterized in that: The fully controlled commutation valve module includes a three-phase bridge arm circuit; each sub-bridge arm of the three-phase bridge arm circuit includes at least one integrated gate-commutated thyristor unit; the integrated gate-commutated thyristor unit includes: integrated gate-commutated thyristors; A dynamic voltage balancing branch, used for performing AC voltage balancing on the integrated gate-commutated thyristor; A static voltage balancing branch, used for performing DC voltage balancing on the integrated gate-commutated thyristor; An integrated controller, used to control the on or off of the integrated gate-commutated thyristor; Among them, the anode of the integrated gate-commutated thyristor is respectively connected to one end of the dynamic voltage balancing branch and one end of the static voltage balancing branch, the other end of the dynamic voltage balancing branch is connected to the integrated controller, and the cathode of the integrated gate-commutated thyristor is respectively connected to the other end of the static voltage balancing branch and the integrated controller.

2. The fully controlled converter valve module according to claim 1, characterized in that: Each sub-bridge arm of the three-phase bridge arm circuit includes at least two integrated gate-commutated thyristor units connected in series.

3. The fully controlled converter valve module according to claim 1 or 2, characterized in that: The dynamic voltage balancing branch includes a first resistor and a capacitor; One end of the first resistor is connected to the anode of the integrated gate-commutated thyristor, and the other end of the first resistor is connected to the integrated controller through the capacitor.

4. The fully controlled converter valve module according to claim 1 or 2, characterized in that: The static voltage-sharing branch includes a second resistor; the second resistor is connected in parallel to the anode and cathode of the integrated gate-commutated thyristor.

5. A fully controlled static frequency converter, characterized in that: The fully controlled static frequency converter comprises a rectifier-side fully controlled converter valve, a smoothing reactor and an inverter-side fully controlled converter valve connected in sequence; Wherein, the rectifier-side fully-controlled converter valve and the inverter-side fully-controlled converter valve each include at least one cascaded fully-controlled converter valve module according to any one of claims 1 to 4.

6. The fully controlled static inverter according to claim 5, characterized in that: The rectifier-side fully-controlled converter valve includes two cascaded fully-controlled converter valve modules; The inverter-side fully-controlled converter valve includes a fully-controlled converter valve module, or the inverter-side fully-controlled converter valve includes two cascaded fully-controlled converter valve modules.

7. The fully controlled static inverter according to claim 5, characterized in that: The fully controlled static frequency converter further comprises: Multiple groups of lightning arresters; each group of the lightning arresters is arranged corresponding to each of the fully-controlled converter valve modules, and the lightning arresters are used to provide overvoltage protection for the fully-controlled converter valve modules.

8. The fully controlled static inverter according to claim 5, characterized in that: The fully controlled static frequency converter further comprises: Multiple groups of magnetic rings; each group of magnetic rings is correspondingly arranged with each of the fully-controlled converter valve modules, and the magnetic rings are used to suppress sudden changes in the AC side current of the fully-controlled converter valve module.

9. A power transmission system, characterized in that: The power transmission system comprises: rectifier transformer; Inverter transformer; The fully controlled static frequency converter according to any one of claims 5 to 8; The rectifier transformer is connected to the rectifier-side fully-controlled converter valve of the fully-controlled static inverter, and the inverter transformer is connected to the inverter-side fully-controlled converter valve of the fully-controlled static inverter.

10. A method for controlling a fully controlled static frequency converter, characterized in that: Used for a fully controlled static frequency converter control system, wherein the fully controlled static frequency converter control system is connected to the fully controlled static frequency converter according to any one of claims 5 to 8; The control method of the fully controlled static inverter includes: Generate grid synchronization signal; generating a valve base trigger signal based on the grid synchronization signal; The valve base trigger signal is sent to the fully-controlled static inverter, so that the integrated controller of each integrated gate-commutated thyristor unit in the fully-controlled static inverter controls the opening or closing of the corresponding integrated gate-commutated thyristor based on the valve base trigger signal.

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