Energy storage and consumption device and system in high-voltage direct-current converter valve

Abstract

The invention relates to the technical field of high-voltage direct-current power transmission, in particular to a high-voltage direct-current converter valve internal energy storage and energy consumption device and system, and the device comprises a conversion branch and an energy storage and energy consumption branch which are connected in parallel; the converter branch is formed by connecting a first half-control valve and a first full-control valve in series, the first half-control valve is formed by connecting a first thyristor in parallel with a first resistance-capacitance branch, and the first full-control valve is formed by connecting a first insulating tube in parallel with a second resistance-capacitance branch; the energy storage and consumption branch is formed by sequentially connecting a second full-control valve, a third full-control valve and a second half-control valve in series, the second full-control valve comprises a second insulating tube, a third insulating tube, a diode, a third resistor and a third capacitor, and the third full-control valve comprises a fourth insulating tube, a fourth capacitor and an energy storage unit. And the second half-control valve is formed by connecting a second thyristor in parallel with a third resistance-capacitance branch. According to the invention, the defects of high commutation failure risk and insufficient power fluctuation regulation capability of a traditional power grid commutation system are effectively solved.

Description

Technical Field

[0001] The present invention relates to the technical field of high - voltage direct - current (HVDC) power transmission, and in particular, to an energy - storing and energy - consuming device and system inside a valve of a high - voltage DC converter. Background Art

[0002] In a high - voltage direct - current (HVDC) power transmission system, commutation failure is a core problem that traditional line - commutated converters (LCC - HVDC) in the power grid have been facing for a long time. That is, it is very likely to occur when a fault occurs in the receiving - end power grid, resulting in instantaneous or continuous power transmission interruption, accompanied by problems such as over - current impact and a sharp increase in reactive power demand. In severe cases, it may trigger the chain blocking of multiple DC lines. The fundamental reason is that the thyristor device fails to turn off reliably and recover its forward - blocking ability during the commutation process.

[0003] In the prior art, although enhancing the strength of the AC system, optimizing the thyristor trigger angle, or configuring a resistor - capacitor buffer circuit can partially alleviate commutation failure, there are significant limitations. Such methods only target a single fault scenario (such as commutation failure or power fluctuation), lacking the collaborative design of the converter structure and control strategy, resulting in functional fragmentation and resource redundancy; traditional energy - consuming devices (such as centralized resistors) can only passively consume power surplus and cannot store energy, while the distributed energy - storage scheme of flexible DC (such as MMC sub - module energy storage) is difficult to be compatible with the thyristor topology of LCC - HVDC, resulting in a contradiction between economy and adaptability; the mismatch between the thyristor turn - off recovery time and the system response speed further exacerbates the fault risk.

[0004] The information disclosed in this background - art section is only intended to deepen the understanding of the overall background technology of the present disclosure, and should not be regarded as an admission or an implication in any form that this information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0005] The present invention provides an energy - storing and energy - consuming device and system inside a valve of a high - voltage DC converter, which can effectively solve the problems in the background art.

[0006] In order to achieve the above - mentioned purpose, the technical solution adopted by the present invention is as follows: An energy - storing and energy - consuming device inside a valve of a high - voltage DC converter includes: It is composed of a parallel - connected commutation branch and an energy - storing and energy - consuming branch; The commutation branch is composed of a semi - controlled valve VC1 and a fully - controlled valve VC2 connected in series. The semi - controlled valve VC1 is composed of a first thyristor VT11 in parallel with a first resistor - capacitor branch, and the fully - controlled valve VC2 is composed of a first IGBT VT12 in parallel with a second resistor - capacitor branch; The energy storage and consumption branch is composed of a fully controlled valve VC3, a fully controlled valve VC4, and a semi-controlled valve VC5 connected in series in sequence. The fully controlled valve VC3 includes a second IGBT VT13, a third IGBT VT14, a diode D, a third resistor R, and a third capacitor C d3 , the fully controlled valve VC4 includes a fourth IGBT VT15 and a fourth capacitor C d4 and an energy storage unit. The semi-controlled valve VC5 is composed of a second thyristor VT18 in parallel with a third resistor-capacitor branch

[0007] Further, the first resistor-capacitor branch, the second resistor-capacitor branch, and the third resistor-capacitor branch include: The first resistor-capacitor branch is composed of a first capacitor C d1 and a first resistor R d1 connected in series. In the first resistor-capacitor branch, the capacitance value of the first capacitor C d1 is configured to match the resistance value of the first resistor R d1 to provide a reverse voltage recovery time for the first thyristor VT11 when the commutation branch is turned off; The second resistor-capacitor branch is composed of a second capacitor C d2 and a second resistor R d2 connected in series. In the second resistor-capacitor branch, the capacitance value of the second capacitor C d2 is configured to match the resistance value of the second resistor R d2 to suppress voltage spikes and reduce switching losses when the first IGBT VT12 is turned off; The third resistor-capacitor branch is composed of a fifth capacitor C d5 and a fourth resistor R d5 connected in series. In the third resistor-capacitor branch, the capacitance value of the fifth capacitor C d5 is configured to match the resistance value of the fourth resistor R d5 to provide a reverse voltage recovery time and suppress commutation overvoltage when the second thyristor VT18 of the semi-controlled valve VC5 is turned off.

[0008] Further, the fully controlled valve VC3 includes: The collector of the second IGBT VT13 is connected to the anode of the diode D and one end of the third resistor R. The other end of the third resistor R is connected to the collector of the third IGBT VT14. The cathode of the diode D is connected to the emitter of the third IGBT VT14 and one end of the third capacitor C d3 , and the other end of the third capacitor C d3 is connected to the emitter of the second IGBT VT13; When a fault occurs on the AC side and the surplus power exceeds the threshold, the third IGBT VT14 conducts, and the current flows through the third resistor R and the third capacitor Cd3 , the surplus power is dissipated through the third resistor R, while the third capacitor C d3 absorbs transient energy and charges the energy storage battery VB; When a fault occurs on the AC side and the surplus power does not exceed the threshold, the third IGBT VT14 is turned off, and the current passes through the diode D and the third capacitor C d3 to charge the energy storage battery VB and suppress the rise of the DC bus voltage; When a fault occurs on the DC side, the third IGBT VT14 is turned off, and the energy storage battery VB discharges through the energy storage unit, and the current passes through the third capacitor C d3 and the diode D to supplement the deficit power on the DC side and maintain the stability of the bus voltage.

[0009] Furthermore, the fully controlled valve VC4 includes: The collector of the fourth IGBT VT15 is connected to the positive pole of the fourth capacitor C d4 and the input end of the energy storage unit, and the emitter of the fourth IGBT VT15 is connected to the output end of the energy storage unit; When the energy storage battery VB is charging, the energy storage battery VB charges the fourth capacitor C d4 through the inductor L and absorbs the surplus power; When the energy storage battery VB discharges, the fourth capacitor C d4 discharges to the energy storage battery VB through the inductor L to supplement the deficit power; When operating normally, the fourth IGBT VT15 is turned on, and the energy storage unit maintains voltage balance through the fourth capacitor C d4 ; When it is detected that the DC bus current exceeds the preset safety threshold or a short-circuit fault occurs, the fourth IGBT VT15 is immediately turned off to cut off the connection between the energy storage unit and the main circuit and avoid reverse energy impact.

[0010] Furthermore, the energy storage unit includes: The energy storage unit is composed of a bidirectional buck-boost circuit, and the bidirectional buck-boost circuit includes a fifth IGBT VT16, a sixth IGBT VT17, an inductor L and an energy storage battery VB; The collector of the fifth IGBT VT16 is connected to the fourth capacitor C d4 , and the emitter is connected to the collector of the sixth IGBT VT17 and one end of the inductor L; The emitter of the sixth IGBT VT17 is connected to the negative pole of the energy storage battery VB, and the positive pole of the energy storage battery VB is connected to the other end of the inductor L; The fourth capacitor C d4 is connected to the negative electrode of the energy storage battery VB; When it is detected that the DC bus current exceeds the preset safety threshold or a short - circuit fault occurs, the fourth IGBT VT15 is immediately turned off, and at the same time, the fifth IGBT VT16 and the sixth IGBT VT17 are forced to turn off, so that the energy storage battery VB and the fourth capacitor C d4 enter the isolation state.

[0011] Further, the bidirectional buck - boost circuit works in the following modes, including: Charging mode: The fifth IGBT VT16 remains off, the sixth IGBT VT17 conducts according to the PWM signal. The current flows out from the positive electrode of the energy storage battery VB, and based on the inductor L, the low - voltage energy of the energy storage battery VB is converted into the high - voltage - side energy of the fourth capacitor C d4 for boost charging; Discharging mode: The sixth IGBT VT17 remains off, the fifth IGBT VT16 conducts according to the PWM signal. The current flows out from the fourth capacitor C d4 and, based on the inductor L, the high - voltage energy of the fourth capacitor C d4 is converted into the low - voltage - side energy of the energy storage battery VB for buck discharging; Standby mode: Both the fifth IGBT VT16 and the sixth IGBT VT17 are off, the fourth IGBT VT15 remains on, and the energy storage battery VB and the fourth capacitor C d4 are connected in parallel to the main circuit through the fourth IGBT VT15, so that the voltage across the fourth capacitor C d4 is synchronized with the DC bus voltage.

[0012] Further, the fully - controlled valve VC2 includes: The collector of the first IGBT VT12 is connected to the input end of the commutation branch, and the emitter is connected to the output end of the commutation branch. The second resistor - capacitor branch is composed of the second capacitor C d2 and the second resistor R d2 connected in series and is connected in parallel across the two ends of the first IGBT VT12; During normal operation or commutation, the first IGBT VT12 conducts, and the current flows through the commutation branch to complete commutation; When the commutation branch is turned off, the first IGBT VT12 is controlled to turn off, and the second capacitor C d2 absorbs the transient voltage energy across the two ends of the first IGBT VT12, and the second resistor R d2 limits the charging and discharging current of the capacitor, suppresses voltage spikes and reduces switching losses.

[0013] Further, the semi-controlled valve VC1 and the semi-controlled valve VC5 include: In the semi-controlled valve VC1, the first thyristor VT11 bears a reverse voltage during commutation. The first resistor-capacitor branch provides a reverse voltage recovery time for the first thyristor VT11, and at the same time, through the first capacitor C d1 absorbs the commutation overvoltage; In the semi-controlled valve VC5, the second thyristor VT18 bears a reverse voltage after the energy storage and dissipation branch is turned off. The third resistor-capacitor branch provides a reverse voltage recovery time for the second thyristor VT18, and at the same time, through the fifth capacitor C d5 suppresses the voltage spike; When operating normally, the first thyristor VT11 and the second thyristor VT18 remain conducting, and the current flows through the commutation branch to complete commutation; When a fault occurs, the first thyristor VT11 and the second thyristor VT18 are turned off, and the current is transferred to the energy storage and dissipation branch.

[0014] A high-voltage DC converter valve internal energy storage and dissipation system, the system includes: The system includes a number of SM sub-modules, and the SM sub-modules include a commutation branch and an energy storage and dissipation branch; During the normal commutation process, the commutation branches of all the SM sub-modules receive synchronous trigger signals to form a parallel current path; The commutation branches of each SM sub-module ensure equal voltage distribution through an equalizing control strategy. When commutation is required for a certain arm, a commutation instruction is sent to the target SM sub-module to turn off the commutation branch that needs to be commutated, and the energy storage and dissipation branch is triggered to transfer the current to the energy storage and dissipation branch of the target SM sub-module; The commutation branches of the remaining non-commutated SM sub-modules remain conducting to maintain the overall current continuity of the system; When operating normally, the commutation branches of each SM sub-module evenly divide the load current and achieve current sharing based on current closed-loop control. When a single SM sub-module exits due to a fault, the remaining SM sub-modules increase the conduction ratio to compensate for the power gap of the faulty SM sub-module; All the SM sub-modules are interconnected through a communication bus to exchange voltage, current, and switch status information in real time.

[0015] The above system operates according to a method for controlling energy storage and dissipation in a high-voltage DC converter valve. The method is to control the conduction of semi-controlled valves and fully-controlled valves in the commutation branch to allow current to flow through the commutation branch and perform commutation operations between arms. During the commutation process, the voltage spikes are suppressed according to the resistance-capacitance branch of the commutation branch, and a reverse turn-off condition is provided for the thyristors in the semi-controlled valves. The DC bus voltage and power status are monitored in real time. When power surplus on the AC side or power deficit on the DC side is detected, the fully-controlled valves in the commutation branch are turned off, and the semi-controlled valves of the energy storage and dissipation branch are triggered to switch the current path to the energy storage and dissipation branch. During the current switching process, the turn-off of the semi-controlled valves in the energy storage and dissipation branch is delayed to ensure that the time for the thyristors in the commutation branch to bear reverse voltage meets the blocking recovery requirements. The commutation overvoltage is suppressed according to the resistance-capacitance branch of the energy storage and dissipation branch to prevent secondary faults. During the charge and discharge process of the energy storage and dissipation branch, the energy transfer rate is dynamically adjusted through a bidirectional power conversion circuit to maintain the synchronization of the capacitor voltage with the DC bus. In the fault recovery stage, the power output of the energy storage and dissipation branch is gradually reduced, and a smooth switch is made to the normal commutation mode.

[0016] Through the technical solution of the present invention, the following technical effects can be achieved: Through the dynamic switching and hierarchical control of the in-valve embedded energy storage - dissipation branch, power bidirectional suppression is achieved while suppressing commutation failures, which is compatible with the traditional LCC-HVDC structure and does not require external devices, improving the system reliability, economy and dynamic response ability.

[0017] The above description is only an overview of the technical solution of this application. In order to be able to understand the technical means of this application more clearly, it can be implemented according to the content of the specification. And in order to make the above and other purposes, features and advantages of this application more obvious and understandable, the specific embodiments of this application are given below. Brief Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments recorded in the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0019] Figure 1 It is a topological structure diagram of the in-valve energy storage and dissipation system; Figure 2 It is a specific circuit schematic diagram of the commutation branch and the energy storage and dissipation branch; Figure 3 It is a structural schematic diagram of a high-voltage DC converter valve with in-valve energy storage and dissipation system. Detailed Embodiments

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the present invention belongs. The terms used in the specification of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0022] Embodiment 1; As Figure 1 、 Figure 2 shown, the present application provides an energy storage and energy consumption device inside a high-voltage DC converter valve, including: It is composed of a parallel-connected commutation branch and an energy storage and energy consumption branch; The commutation branch is composed of a semi-controlled valve VC1 and a fully-controlled valve VC2 connected in series. The semi-controlled valve VC1 is composed of a first thyristor VT11 in parallel with a first resistor-capacitor branch, and the fully-controlled valve VC2 is composed of a first IGBT VT12 in parallel with a second resistor-capacitor branch; The energy storage and energy consumption branch is composed of a fully-controlled valve VC3, a fully-controlled valve VC4, and a semi-controlled valve VC5 connected in series in sequence. The fully-controlled valve VC3 includes a second IGBT VT13, a third IGBT VT14, a diode D, a third resistor R, and a third capacitor C d3 , the fully-controlled valve VC4 includes a fourth IGBT VT15, a fourth capacitor C d4 and an energy storage unit, and the semi-controlled valve VC5 is composed of a second thyristor VT18 in parallel with a third resistor-capacitor branch.

[0023] Specifically, the commutation branch is composed of a semi-controlled valve VC1 and a fully-controlled valve VC2 connected in series, undertaking the basic power commutation task, fully considering the balance between commutation speed and overvoltage resistance. The semi-controlled valve VC1 is composed of a thyristor VT11 in parallel with a resistor-capacitor branch (C d1 , R d1 ), the thyristor has good pressure-bearing capacity and impact resistance, and is suitable for undertaking the main commutation task; while the resistor-capacitor branch absorbs voltage spikes when the thyristor is turned off, provides a voltage equalization function, and prevents the device from being damaged due to uneven voltage; the fully-controlled valve VC2 uses an IGBT VT12 in parallel with a resistor-capacitor branch (C d2 , R d2), compared with thyristors, IGBTs support higher frequencies and more flexible on-off control, enabling the system to more precisely control the current waveform during operation, improving system stability. The resistor-capacitor branch further enhances the voltage sharing ability of IGBTs at the moment of switching; the energy storage and dissipation branch is connected in series with three sub-modules, VC3, VC4, and VC5, which are mainly used for energy management, fault energy release, and active support in the system; VC3 is constructed based on IGBTs VT13 and VT14, resistor R, and capacitor C d3 , and diode D. When there is a short-term over-energy or current impact in the system, this structure can quickly release the energy into resistor R and suppress transient fluctuations through capacitor C d3 . At the same time, diode D provides a unidirectional conduction path to ensure that the energy dissipation process does not affect normal operation; VC4 integrates the energy storage function, and its core is a bidirectional Buck-Boost circuit composed of IGBTs VT15, VT16, VT17, inductor L, and energy storage battery VB. This structure enables bidirectional energy flow. When there is excess energy in the power grid, the system stores electrical energy into the battery in a step-down manner; when the power grid needs support, it can boost the output to provide stable voltage support for the system and effectively balance the power fluctuations of the system; VC5 is composed of thyristor VT18 and a resistor-capacitor branch (C d5 , R d5 ), which is used for emergency energy dissipation and safety protection. When a serious fault is detected or the energy storage unit cannot respond in time, VC5 conducts quickly, dissipating the excess energy of the system through the resistor to prevent the voltage from rising further; the resistor-capacitor branch also plays a role in suppressing spikes.

[0024] Through the technical solution of the present invention, the dynamic switching and hierarchical control of the embedded energy storage-dissipation branch in the valve are realized, achieving bidirectional power smoothing while suppressing commutation failures, being compatible with the traditional LCC-HVDC structure without the need for external devices, and improving the reliability, economy, and dynamic response ability of the system.

[0025] Furthermore, the first resistor-capacitor branch, the second resistor-capacitor branch, and the third resistor-capacitor branch include: The first resistor-capacitor branch is composed of a first capacitor C d1 and a first resistor R d1 connected in series. In the first resistor-capacitor branch, the capacitance value of the first capacitor C d1 is configured to match the resistance value of the first resistor R d1 to provide a reverse voltage recovery time for the first thyristor VT11 when the commutation branch is turned off; The second resistor-capacitor branch is composed of a second capacitor C d2 and a second resistor R d2 connected in series. In the second resistor-capacitor branch, the capacitance value of the second capacitor C d2 is configured to match the resistance value of the second resistor R d2The resistance matching configuration suppresses voltage spikes and reduces switching losses when the first IGBT VT12 turns off; The third resistor-capacitor branch consists of a fifth capacitor C d5 and a fourth resistor R d5 connected in series. In the third resistor-capacitor branch, the fifth capacitor C d5 has a capacitance value matched with the resistance value of the fourth resistor R d5 to provide a reverse voltage recovery time and suppress commutation overvoltage when the second thyristor VT18 of the semi-controlled valve VC5 turns off.

[0026] As an optimization of the above embodiment, the matching configuration of the first capacitor C d1 and the first resistor R d1 can ensure that when the thyristor turns off, the system can stably recover the voltage and avoid damage to the thyristor and other system components caused by voltage surges; the capacitor C d1 is mainly responsible for absorbing the overvoltage generated during the current mutation process when the commutation branch turns off and providing a reverse current in a short time. It plays a filtering and smoothing role during the operation of the converter through the energy it stores, reducing voltage fluctuations. The larger the capacitor, the stronger the current impact it can withstand, and at the same time, it can more effectively suppress instantaneous voltage changes; the resistor R d1 and the capacitor C d1 together form an RC circuit, which is mainly used to control the charging and discharging rate of the capacitor C d1 . The setting of the resistor determines the discharging time of the capacitor C d1 , that is, the speed of energy release. Reasonable configuration of the resistance value can avoid excessive current fluctuations or voltage reverse peaks caused by the capacitor discharging too quickly; in the design, the capacitance value of the first capacitor C d1 and the resistance value of the first resistor R d1 need to be precisely matched. The matching configuration of these two can ensure that when the thyristor VT11 turns off, the best balance is achieved between the charging and discharging speed of the capacitor C d1 and the smoothness of the current change, thereby providing an appropriate reverse voltage recovery time; when the thyristor VT11 turns off, the current gradually decreases and a reverse voltage is generated. If the matching of the resistor and the capacitor is improper, it may cause the capacitor to discharge too quickly, resulting in too fast voltage recovery and even overvoltage surges, damaging the components. On the contrary, if the discharging is too slow, it may lead to too long thyristor voltage recovery time, affecting the commutation efficiency; the selection of the capacitor C d1 needs to ensure that it can absorb and store an appropriate amount of electrical energy, while the resistor R d1 should have an appropriate resistance value so that during the commutation turn-off process, the capacitor can release the stored energy at an appropriate speed, effectively recovering the reverse voltage and avoiding the impact of overvoltage or current mutation on the system; by precisely matching the first capacitor C d1 and the first resistor R d1, the present invention can ensure that during the turn-off process of thyristor VT11, the system can smoothly recover the voltage, avoiding current or voltage surges caused by too fast or too slow voltage recovery. At the same time, this configuration improves the stability and durability of the entire system, reduces the damage to the converter components caused by voltage surges, and thus extends the service life of the system; the second resistor-capacitor branch is mainly used to suppress voltage spikes and reduce switching losses. In this branch, capacitor C d2 and resistor R d2 are configured similarly to the first resistor-capacitor branch, both by precisely matching the capacitance and resistance values to control the charge and discharge rate. Capacitor C d2 is responsible for absorbing and storing energy, and resistor R d2 determines the discharge speed. The difference is that the second resistor-capacitor branch pays more attention to suppressing voltage spikes during the switching process. Therefore, the selection of the capacitor and resistor will be optimized differently according to the switching characteristics and energy absorption requirements; the function of the third resistor-capacitor branch is to provide reverse voltage recovery time and suppress commutation overvoltage. The selection of capacitor C d5 and resistor R d5 is similar to that of the first branch, and it also affects the response speed and stability of the system by controlling the capacitor charge and discharge rate. Since the role of the third resistor-capacitor branch is to deal with the overvoltage during commutation, the selection of the capacitor and resistor will be adjusted according to the specific commutation overvoltage characteristics.

[0027] Furthermore, the fully controlled valve VC3 includes: The collector of the second IGBT VT13 is connected to the anode of diode D and one end of the third resistor R. The other end of the third resistor R is connected to the collector of the third IGBT VT14. The cathode of diode D is connected to the emitter of the third IGBT VT14 and one end of the third capacitor C d3 , and the other end of the third capacitor C d3 is connected to the emitter of the second IGBT VT13; When a fault occurs on the AC side and the surplus power exceeds the threshold, the third IGBT VT14 conducts, and the current flows through the third resistor R and the third capacitor C d3 , dissipating the surplus power through the third resistor R. At the same time, the third capacitor C d3 absorbs transient energy and charges the energy storage battery VB; When a fault occurs on the AC side and the surplus power does not exceed the threshold, the third IGBT VT14 turns off, and the current charges the energy storage battery VB through diode D and the third capacitor C d3 to suppress the rise of the DC bus voltage; When a fault occurs on the DC side, the third IGBT VT14 turns off, and the energy storage battery VB discharges through the energy storage unit. The current passes through the third capacitor C d3 and diode D to supplement the deficit power to the DC side and maintain the stability of the bus voltage.

[0028] Preferably, in the energy storage and energy consumption device in the high-voltage DC converter valve, a fully controlled valve VC3 is provided to achieve dynamic management of energy and enhancement of system stability under different operating states. The fully controlled valve VC3 includes a second insulated gate bipolar transistor (second IGBT VT13), a third insulated gate bipolar transistor (third IGBT VT14), a fast recovery diode D, a third resistor R, and a third capacitor C d3 , in terms of structural connection, the collector of the second IGBT VT13 is electrically connected to the anode of the diode D and one end of the third resistor R, the other end of the third resistor R is connected to the collector of the third IGBT VT14, the cathode of the diode D is connected to the emitter of the third IGBT VT14 and one end of the third capacitor C d3 ; one end of the third capacitor C d3 is connected to the emitter of the second IGBT VT13, thus forming a closed power circulation branch. The third capacitor C d3 is arranged in parallel with the energy storage battery VB and can be used for energy absorption and release. During operation, when a fault occurs on the AC side and there is a large surplus power, if it is judged that it exceeds the set threshold, in order to avoid a rapid rise in the bus voltage or system energy accumulation, the third IGBT VT14 is driven to conduct. At this time, the current flows through the third resistor R and the third capacitor C in sequence d3 , the surplus power in the system is dissipated through the third resistor R, thereby reducing the system risk brought by energy concentration. At the same time, the third capacitor C d3 absorbs and buffers the transient current in the circuit, transfers part of the energy to the energy storage battery VB, and improves the emergency capacity of the energy storage unit; if a fault occurs on the AC side but the surplus power does not exceed the set control threshold, the third IGBT VT14 is kept in the off state. At this time, the current path flows through the diode D and the third capacitor C d3 to the energy storage battery VB, realizing the normal charging process of the energy storage battery. At the same time, the third capacitor C d3 plays a role in suppressing the rapid rise of the DC bus voltage, avoiding system instability or mis-triggering of protection actions caused by excessive bus voltage fluctuations; when a fault occurs on the DC side, such as abnormal situations such as voltage drop, sudden increase in load or power supply interruption, the control system turns off the third IGBT VT14 and controls the energy storage battery VB to release the stored energy to compensate for the power gap on the DC side. During this process, the current output by the energy storage battery VB passes through the third capacitor C d3 and the diode D in sequence and outputs to the DC side. The third capacitor C d3Provide the necessary voltage buffer for the output current to improve the stability of power transfer. The diode D ensures that the current flows unidirectionally to the load and prevents the reverse flow of voltage from affecting the energy storage system, thereby effectively maintaining the stable operation of the DC bus voltage under fault conditions. The fully controlled valve VC3 in this embodiment can achieve reasonable energy distribution and conversion under different working scenarios through the coordinated cooperation of key components such as the second IGBT, the third IGBT, the resistor-capacitor network, and the diode, improving the anti-interference ability of the converter under fault conditions and the overall operation safety of the system. The capacitance C d3 The specific parameters of the resistor R can be engineered and matched according to the design capacity of the power module, the bus voltage level, and the response speed of the energy storage system, etc., to ensure the coordinated cooperation of energy absorption, dissipation, and output under various operating states.

[0029] Furthermore, the fully controlled valve VC4 includes: The collector of the fourth IGBT VT15 is connected to the positive electrode of the fourth capacitor C d4 and the input end of the energy storage unit, and the emitter of the fourth IGBT VT15 is connected to the output end of the energy storage unit; When the energy storage battery VB is charging, the energy storage battery VB charges the fourth capacitor C d4 through the inductor L, absorbing the surplus power; When the energy storage battery VB is discharging, the fourth capacitor C d4 discharges to the energy storage battery VB through the inductor L to supplement the deficit power; When operating normally, the fourth IGBT VT15 is turned on, and the energy storage unit maintains voltage balance through the fourth capacitor C d4 ; When it is detected that the DC bus current exceeds the preset safety threshold or a short-circuit fault occurs, the fourth IGBT VT15 is immediately turned off, cutting off the connection between the energy storage unit and the main circuit to avoid reverse energy impact.

[0030] As an optimization of the above embodiment, the energy storage and energy dissipation device inside the high-voltage DC converter valve further includes a fully controlled valve VC4, which is used to realize the bidirectional energy flow control and safety isolation between the energy storage unit and the main circuit. The fully controlled valve VC4 includes a fourth insulated gate bipolar transistor (fourth IGBT VT15), a fourth capacitor C d4 , an inductor L, and an energy storage unit electrically connected to the energy storage battery VB; in terms of the connection relationship of components, the collector of the fourth IGBT VT15 is connected to the positive electrode of the fourth capacitor C d4 and the input end of the energy storage unit, and the emitter of the fourth IGBT VT15 is connected to the output end of the energy storage unit, thereby forming a current control path. The fourth capacitor C d4It is connected to the energy storage battery VB through an inductor L, which is used to suppress current mutation during the charging and discharging process, improve system stability and power transmission efficiency; under normal operating conditions, when the DC system operates stably and the load is balanced with the power supply, the control unit drives the fourth IGBT VT15 to conduct, enabling the energy storage unit to be stably connected to the fourth capacitor C d4 to maintain a stable connection. At this time, the energy storage unit can dynamically buffer voltage fluctuations under the support of the fourth capacitor C d4 to achieve voltage equalization control, improve the power quality and operating stability of the converter; when there is an excess of AC-side power, the control system monitors that the energy storage battery VB is in the charging state and starts the energy storage process. The energy storage battery VB charges the fourth capacitor C d4 through the inductor L. The inductor L limits the rate of change of current during the charging process to prevent damage to devices caused by large current shocks. The fourth capacitor C d4 absorbs and temporarily stores the excess electrical energy, thereby improving the power buffering capacity of the energy storage unit, enabling the system to respond quickly when the load changes suddenly, and preventing the bus voltage from rising abnormally; when there is a power gap on the DC side and it enters the discharge mode, the control unit triggers the energy storage battery VB to discharge according to the load demand. At this time, the fourth capacitor C d4 releases the stored energy to the energy storage battery VB through the inductor L to supplement the required power. The inductor L also plays a role in current limiting protection during the discharge process to ensure the safe operation between the battery and the main circuit and improve the continuity of power supply; to enhance safety performance, when it is detected that the DC bus current exceeds the preset safety threshold or a serious fault such as a short circuit occurs, a control command is issued to turn off the fourth IGBT VT15. By turning off this IGBT device, the connection between the energy storage unit and the main circuit is quickly cut off, avoiding continuous power supply from the energy storage battery to the fault point, preventing damage to the system or local overheating caused by reverse energy shock, and effectively protecting the safety of the energy storage device and the entire DC converter system; in this embodiment, through the coordinated control of components such as the fourth IGBT VT15, capacitor C d4 and inductor L, not only can the efficient charging and discharging of the energy storage battery be achieved, but also the power supply and isolation modes can be actively switched according to the operating state to ensure stable and reliable power support under normal and fault conditions. The parameter configuration of the above components can be optimized and matched according to factors such as the system design capacity, voltage level, and protection strategy to meet the usage requirements in different engineering scenarios.

[0031] Furthermore, the energy storage unit includes: The energy storage unit is composed of a bidirectional buck-boost circuit, and the bidirectional buck-boost circuit includes a fifth IGBT VT16, a sixth IGBT VT17, an inductor L, and an energy storage battery VB; The collector of the fifth IGBT VT16 is connected to the fourth capacitor C d4, the emitter is connected to the collector of the sixth IGBT VT17 and one end of the inductor L; The emitter of the sixth IGBT VT17 is connected to the negative electrode of the energy storage battery VB, and the positive electrode of the energy storage battery VB is connected to the other end of the inductor L; The fourth capacitor C d4 is connected to the negative electrode of the energy storage battery VB; When it is detected that the DC bus current exceeds the preset safety threshold or a short - circuit fault occurs, the fourth IGBT VT15 is immediately turned off, and at the same time, the fifth IGBT VT16 and the sixth IGBT VT17 are forced to turn off, so that the energy storage battery VB and the fourth capacitor C d4 enter the isolation state.

[0032] As an optimization of the above - mentioned embodiment, the energy storage unit adopts a bidirectional buck - boost circuit structure to achieve bidirectional energy flow control of the energy storage battery VB. The energy storage unit mainly consists of the fifth insulated gate bipolar transistor (the fifth IGBT VT16), the sixth insulated gate bipolar transistor (the sixth IGBT VT17), the inductor L, the energy storage battery VB, and the fourth capacitor C d4 cooperating therewith; from the perspective of electrical connection relationship, the fourth capacitor C d4 is connected to the input side of the energy storage unit and is connected to the collector of the fifth IGBT VT16 through a line. The emitter of the fifth IGBT VT16 is connected to the collector of the sixth IGBT VT17 and also connected to one end of the inductor L to form the main power transmission path. The emitter of the sixth IGBT VT17 is further connected to the negative electrode of the energy storage battery VB, and the positive electrode of the energy storage battery VB is connected to the circuit through the other end of the inductor L. The entire energy storage unit takes the inductor L as the core coupling element and controls the bidirectional flow of electric energy through two - stage IGBT switching devices to achieve adaptive conversion of step - up and step - down; during the charging stage of the energy storage battery VB, when it is detected that there is power surplus and the bus voltage is relatively high, by controlling the fifth IGBT VT16 and the sixth IGBT VT17 to conduct alternately according to a certain PWM control strategy, a buck mode is constructed. In this mode, the electric energy from the main circuit passes through the fourth capacitor C d4Enter the energy storage unit, pass through the fifth IGBT VT16, inductor L, and the sixth IGBT VT17, and finally enter the energy storage battery VB. The inductor L plays a role in temporarily storing energy and buffering current during this process, ensuring a smooth battery charging process and avoiding damage to the battery caused by large currents. During the discharge stage of the energy storage battery, that is, when the load of the DC system increases or the DC bus voltage drops, the fifth IGBT VT16 and the sixth IGBT VT17 operate in a boost mode under the drive of the control system. The energy storage battery VB releases energy, stores energy through the inductor L, and then is released to the main circuit by switch control. By means of the conversion of the magnetic energy of the inductor, the output voltage is increased to meet the power supply demand of the bus. This process effectively guarantees the power supply stability of the system under conditions such as voltage dips and sudden load increases. To enhance safety in the fault state, when it is detected that the DC bus current exceeds the preset safety threshold or a serious fault such as a short circuit occurs, a control signal is immediately sent to make the fourth IGBT VT15 enter the off state, quickly cutting off the direct connection between the energy storage unit and the main circuit. At the same time, the control system synchronously turns off the fifth IGBT VT16 and the sixth IGBT VT17, forcibly stopping the energy interaction between the energy storage battery VB and other components in the circuit, ensuring that the fourth capacitor C d4 is isolated from the energy storage battery, avoiding damage to the main circuit or the energy storage module caused by reverse energy flow, thereby enhancing the electrical safety and fault suppression ability of the entire converter system.

[0033] Furthermore, the bidirectional buck-boost circuit works in the following modes, including: Charging mode: The fifth IGBT VT16 remains off, and the sixth IGBT VT17 conducts according to the PWM signal. The current flows out from the positive pole of the energy storage battery VB. Based on the inductor L, the low-voltage energy of the energy storage battery VB is converted into the high-voltage side energy of the fourth capacitor C d4 for boost charging. Discharge mode: The sixth IGBT VT17 remains off, and the fifth IGBT VT16 conducts according to the PWM signal. The current flows out from the fourth capacitor C d4 Based on the inductor L, the high-voltage energy of the fourth capacitor C d4 is converted into the low-voltage side energy of the energy storage battery VB for buck discharge. Standby mode: Both the fifth IGBT VT16 and the sixth IGBT VT17 are off, and the fourth IGBT VT15 remains conducting. The energy storage battery VB and the fourth capacitor C d4 are connected in parallel to the main circuit through the fourth IGBT VT15, making the voltage across the fourth capacitor C d4 synchronized with the DC bus voltage.

[0034] As an optimization of the above embodiment, in the charging mode, when it is detected that it is necessary to convert the low-voltage energy in the energy storage battery VB into a higher voltage to supplement the fourth capacitor Cd4 At this time, the fifth IGBT VT16 is kept off to prevent the electric energy from the main circuit from flowing into the energy storage battery. At the same time, the sixth IGBT VT17 is turned on according to the PWM signal to adjust the switching frequency and conduction time, and precisely control the current flow direction. The current flows out from the positive pole of the energy storage battery VB, passes through the sixth IGBT VT17, and flows to the inductor L. The inductor L, as an energy storage element, temporarily stores the low-voltage electric energy in the energy storage battery through its magnetic field and releases it at an appropriate time. In this process, the role of the inductor L is to convert the direction and energy characteristics of the current, so that the low-voltage energy of the energy storage battery VB is boosted to a higher voltage through the inductor and supplied to the fourth capacitor C d4 , the fourth capacitor C d4 After charging, the stored energy can be used to further support the main circuit or provide an instantaneous power supply. In this mode, when the current passes through the inductor L, the increase and decrease of the current are affected by the PWM control signal. Therefore, the charging rate can be precisely adjusted to avoid damage to the battery or circuit caused by sudden current changes. In the discharge mode, when it is detected that the load demand increases or the DC bus voltage drops, and it is necessary to release the stored high-voltage energy to supplement the power demand of the system. At this time, the sixth IGBT VT17 is kept off to cut off the connection between the energy storage battery VB and the circuit, while the fifth IGBT VT16 is turned on according to the PWM signal to achieve reverse current flow. The current flows out from the fourth capacitor C d4 and enters the inductor L through the turned-on fifth IGBT VT16. Under the action of the inductor L, the high-voltage energy stored in the capacitor is converted into a lower voltage to meet the input requirements of the energy storage battery VB. The inductor L acts as a role of energy transfer and current regulation, and ensures that the energy flows into the energy storage battery at an appropriate rate by gradually releasing the stored energy. The key to this process is the reversal of the current flow direction. By controlling the conduction time and switching frequency of the fifth IGBT VT16, the discharge rate can be flexibly adjusted, so that the energy storage battery VB can obtain the required low-voltage charging to ensure the efficient and safe discharge of the battery. In the standby mode, when in a state where no charge or discharge is required, both the fifth IGBT VT16 and the sixth IGBT VT17 are kept off. At this time, the energy storage battery VB and the fourth capacitor C d4 are connected through the fourth IGBT VT15 and are connected in parallel to the main circuit. This design ensures that the energy storage unit can maintain synchronization with the main circuit without affecting the normal operation of the main circuit when no charge or discharge is performed. In this mode, the voltage across the fourth capacitor C d4 will be synchronized with the DC bus voltage. In this way, the fourth capacitor C d4It can play the role of stabilizing voltage, avoiding excessive fluctuations, maintaining the electrical energy stability of the system. The conducting state of the fourth IGBT VT15 ensures the safe parallel connection of the capacitor and the battery to the main circuit, avoiding the risks brought by abnormal voltage or current fluctuations; through this standby mode design, the system can maintain a standby state when there is no need for charging or discharging, ensuring that it can respond quickly when the load changes and switch to the charging or discharging mode, thus achieving efficient energy management and system protection.

[0035] Furthermore, the fully controlled valve VC2 includes: The collector of the first IGBT VT12 is connected to the input end of the commutation branch, and the emitter is connected to the output end of the commutation branch. The second resistor-capacitor branch is composed of a second capacitor C d2 and a second resistor R d2 connected in series and paralleled across the two ends of the first IGBT VT12; During normal operation or commutation, the first IGBT VT12 conducts, and the current flows through the commutation branch to complete commutation; When the commutation branch is turned off, the first IGBT VT12 is controlled to turn off, and the second capacitor C d2 absorbs the transient voltage energy across the two ends of the first IGBT VT12, and the second resistor R d2 limits the charging and discharging current of the capacitor, suppresses voltage spikes and reduces switching losses.

[0036] As a preference of the above embodiment, during normal operation or commutation, the operation of the current flowing through the commutation branch is achieved by the conduction of the first IGBT VT12. At this time, the collector of the first IGBT VT12 is connected to the input end of the commutation branch, and its emitter is connected to the output end of the commutation branch, ensuring that the current can smoothly pass through the commutation branch to complete the electrical energy conversion. The commutation branch is in a conducting state at this stage and can stably transmit the current to the load end to ensure the normal operation of the converter. At this time, the second resistor-capacitor branch is composed of a second capacitor C d2 and a second resistor R d2 connected in series and paralleled across the two ends of the first IGBT VT12. The function of the second capacitor C d2 is to buffer voltage fluctuations and absorb the transient voltage caused by current fluctuations to avoid damage to IGBTs or other circuit components due to high-frequency voltage fluctuations. At the same time, the second resistor R d2 and the capacitor C d2 control the charging and discharging process together, limit the charging and discharging current of the capacitor, ensure the smooth progress of the charging and discharging process, and avoid excessive current causing losses; when the commutation branch is turned off, the first IGBT VT12 is controlled to turn off, that is, the conducting state is closed to prevent the current from continuing to flow through the commutation branch. At this time, the second capacitor C d2Absorb the transient voltage energy from both ends of the first IGBT VT12. Due to the sudden stop of the current during the commutation process, instantaneous high-voltage peaks may be generated at both ends of the first IGBT VT12. These high-voltage peaks may damage the IGBT or other components of the system. At this time, the second capacitor C d2 will quickly absorb these transient voltages and, through its own energy storage capacity, slow down the voltage rise to avoid the appearance of voltage spikes. To ensure that the charging and discharging process does not cause excessive current fluctuations or damage the circuit, the second resistor R d2 plays a role in restricting the charging and discharging current of the capacitor. The presence of the resistor can effectively slow down the charging and discharging rate of the capacitor, avoid excessive current, thereby suppressing switching losses and ensuring the stable operation of the system. In this case, the selection of the resistor value is crucial. A reasonable resistor value can balance the current overshoot and the stability of charging and discharging, and optimize the efficiency of the entire commutation process; through the second capacitor C d2 and the second resistor R d2 cooperate, the second RC branch can effectively suppress voltage spikes and reduce switching losses. The second capacitor C d2 absorbs the instantaneous voltage generated when the commutation branch is turned off, reducing high-frequency noise and voltage fluctuations in the system; while the second resistor R d2 restricts the charging and discharging rate of the capacitor to ensure that the current does not change violently, thereby reducing the switching losses caused by current fluctuations.

[0037] Furthermore, the semi-controlled valves VC1 and VC5 include: In the semi-controlled valve VC1, the first thyristor VT11 bears a reverse voltage during commutation. The first RC branch provides a reverse voltage recovery time for the first thyristor VT11 and, at the same time, absorbs the commutation overvoltage through the first capacitor C d1 ; In the semi-controlled valve VC5, the second thyristor VT18 bears a reverse voltage after the energy storage and dissipation branch is turned off. The third RC branch provides a reverse voltage recovery time for the second thyristor VT18 and, at the same time, suppresses voltage spikes through the fifth capacitor C d5 ; When operating normally, the first thyristor VT11 and the second thyristor VT18 remain conducting, and the current flows through the commutation branch to complete commutation; When a fault occurs, the first thyristor VT11 and the second thyristor VT18 are turned off, and the current is transferred to the energy storage and dissipation branch.

[0038] As a preference of the above embodiment, the semi-controlled valve VC1 includes the first thyristor VT11 and the first RC branch connected in parallel across its two ends. This branch consists of the first capacitor C d1 and the first resistor R d1Connected in series. During the commutation process, the first thyristor VT11 serves as the leading conducting device to complete AC commutation. When the commutation branch is turned off, the first thyristor VT11 turns off and bears the reverse voltage from the line. At this time, the first resistor-capacitor branch plays an important role. The first capacitor C d1 absorbs the commutation overvoltage generated at the moment of turn-off to prevent the device from being damaged by the peak voltage impact; at the same time, the first resistor R d1 limits the charging and discharging current of the capacitor to ensure that the energy is released at a controllable rate; the RC parameter matching design ensures that sufficient reverse voltage recovery time is provided for the first thyristor VT11 to enable it to reliably enter the blocking state. In a typical operating scenario, such as when switching from the operating state to the energy transfer stage, the first thyristor VT11 needs to turn off quickly, and C d1 absorbs the voltage mutation caused by commutation in a timely manner, and at the same time, through R d1 releases it gently to achieve voltage recovery control; the semi-controlled valve VC5 includes the second thyristor VT18 and the third resistor-capacitor branch, which is composed of the fifth capacitor C d5 and the fourth resistor R d5 connected in series. The second thyristor VT18 serves as the main control device in the energy storage and energy consumption branch to control during system faults or energy feedback states. After the energy storage and energy consumption branch is turned off, the second thyristor VT18 needs to bear the possible reverse voltage in the line. At this time, the fifth capacitor C d5 absorbs the overvoltage and suppresses the reverse voltage fluctuation, and the fourth resistor R d5 then restricts and controls the charging and discharging process of C d5 to ensure that the capacitor releases energy smoothly and avoid the voltage peak from being conducted to the main circuit again. The overall third resistor-capacitor branch ensures that the second thyristor VT18 has sufficient reverse voltage recovery time to safely complete the commutation switching process. For example, when the bus is detected to be abnormal or it is necessary to quickly transfer to the energy storage branch for energy transfer, the second thyristor VT18 turns off at the moment of switching, and the third resistor-capacitor branch immediately provides a reverse bias voltage to make it reliably blocked and absorb the commutation impact energy; during normal operation, both the first thyristor VT11 and the second thyristor VT18 remain in the conducting state, and the current flows through the commutation branch. At this time, the energy storage and energy consumption branch is in an inactive state, and the resistor-capacitor branch does not participate in the main energy conversion process and only remains in a static standby state. The current flows stably through the thyristor conduction channel to complete the normal commutation of energy; once abnormal situations such as DC bus overvoltage and AC side short circuit are detected, the first thyristor VT11 and the second thyristor VT18 will quickly turn off, cut off the original commutation path, and the current will immediately switch to the energy storage and energy consumption branch, and the energy will be transferred and consumed by the subsequent fully controlled valve and energy storage unit. At the moment when the thyristor turns off, the resistor-capacitor branch responds in a timely manner to provide the necessary reverse voltage recovery time and overvoltage suppression channel for the first thyristor VT11 and the second thyristor VT18 respectively, ensuring the safe switching of components and preventing the voltage peak from affecting the system stability.

[0039] Embodiment 2; Based on the same inventive concept as the energy storage and energy consumption device in a high-voltage DC converter valve in the foregoing embodiment, the present invention further provides a high-voltage DC converter valve internal energy storage and energy consumption system, as Figure 3 shown, the system includes: The system includes a number of SM sub-modules, and each SM sub-module includes a commutation branch and an energy storage and energy consumption branch; During the normal commutation process, the commutation branches of all SM sub-modules receive synchronous trigger signals to form a parallel current path; The commutation branches of each SM sub-module ensure balanced voltage distribution through an equalizing control strategy. When a certain arm needs to be commutated, a commutation instruction is sent to the target SM sub-module to turn off the commutation branch to be commutated, and the energy storage and energy consumption branch is triggered to transfer the current to the energy storage and energy consumption branch of the target SM sub-module; The commutation branches of the remaining non-commutated SM sub-modules remain conducting to maintain the overall current continuity of the system; During normal operation, the commutation branches of each SM sub-module equally divide the load current and achieve current sharing based on current closed-loop control. When a single SM sub-module exits due to a fault, the remaining SM sub-modules increase the conduction ratio to compensate for the power gap of the faulty SM sub-module; All SM sub-modules are interconnected through a communication bus to exchange voltage, current, and switch status information in real time.

[0040] The above system operates according to a method for controlling energy storage and energy consumption in a high-voltage DC converter valve. The method is to control the conduction of semi-controlled valves and fully-controlled valves in the commutation branch to make the current flow through the commutation branch and perform the commutation operation between arms; during the commutation process, suppress the voltage spike according to the resistance-capacitance branch of the commutation branch and provide a reverse turn-off condition for the thyristor in the semi-controlled valve; monitor the DC bus voltage and power status in real time. When it is detected that there is power surplus on the AC side or power deficit on the DC side, turn off the fully-controlled valve of the commutation branch and trigger the semi-controlled valve of the energy storage and energy consumption branch to switch the current path to the energy storage and energy consumption branch; during the current switching process, delay the turn-off of the semi-controlled valve of the energy storage and energy consumption branch to ensure that the time for the thyristor in the commutation branch to withstand the reverse voltage meets the blocking recovery requirements; suppress the commutation overvoltage according to the resistance-capacitance branch of the energy storage and energy consumption branch to prevent secondary faults. During the charge and discharge process of the energy storage and energy consumption branch, dynamically adjust the energy transfer rate through a bidirectional power conversion circuit to maintain the capacitor voltage in synchronization with the DC bus; during the fault recovery stage, gradually reduce the power output of the energy storage and energy consumption branch and smoothly switch to the normal commutation mode.

[0041] The above system in the present invention can effectively implement an energy storage and energy consumption device in a high-voltage DC converter valve, and the technical effects that can be achieved are as described in the above embodiment, which will not be elaborated here.

[0042] Although the present application has been described in connection with specific features and their embodiments, it will be apparent that various modifications and combinations can be made without departing from the spirit and scope of the present application. Accordingly, the specification and drawings are merely exemplary illustrations of the present application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of the present application. Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the scope of the present application. Thus, if these modifications and variations of the present application fall within the scope of the present application and its equivalent technologies, the present application is intended to include these changes and modifications.

Claims

1. A high-voltage DC converter valve internal energy storage and energy consumption device, characterized in that It includes: It is composed of a parallel-connected commutation branch and an energy storage and energy consumption branch; The commutation branch is composed of a semi-controlled valve VC1 and a fully-controlled valve VC2 connected in series. The semi-controlled valve VC1 is composed of a first thyristor VT11 in parallel with a first resistor-capacitor branch, and the fully-controlled valve VC2 is composed of a first IGBT VT12 in parallel with a second resistor-capacitor branch; The energy storage and consumption branch circuit is composed of a fully controlled valve VC3, a fully controlled valve VC4, and a semi-controlled valve VC5 connected in series in sequence. The fully controlled valve VC3 includes a second IGBT VT13, a third IGBT VT14, a diode D, a third resistor R, and a third capacitor C d3 , the fully controlled valve VC4 includes a fourth IGBT VT15 and a fourth capacitor C d4 and an energy storage unit. The semi-controlled valve VC5 is constituted by a second thyristor VT18 in parallel with a third resistor-capacitor branch 2. The energy storage and energy consumption device in the high-voltage DC converter valve according to claim 1, characterized in that, The first resistor-capacitor branch, the second resistor-capacitor branch, and the third resistor-capacitor branch include: The first resistor-capacitor branch is composed of a first capacitor C d1 and a first resistor R d1 connected in series. In the first resistor-capacitor branch, the capacitance value of the first capacitor C d1 is configured to match the resistance value of the first resistor R d1 to provide a reverse voltage recovery time for the first thyristor VT11 when the commutation branch is turned off; The second resistor-capacitor branch is composed of a second capacitor C d2 and a second resistor R d2 connected in series. In the second resistor-capacitor branch, the capacitance value of the second capacitor C d2 is configured to match the resistance value of the second resistor R d2 to suppress voltage spikes and reduce switching losses when the first IGBT VT12 is turned off; The third resistor-capacitor branch is composed of a fifth capacitor C d5 and a fourth resistor R d5 connected in series. In the third resistor-capacitor branch, the capacitance value of the fifth capacitor C d5 is configured to match the resistance value of the fourth resistor R d5 to provide a reverse voltage recovery time and suppress commutation overvoltage when the second thyristor VT18 of the semi-controlled valve VC5 is turned off.

3. The energy storage and energy consumption device in the HVDC converter valve according to claim 1, characterized in that, The fully-controlled valve VC3 includes: The collector of the second IGBT VT13 is connected to the anode of the diode D and one end of the third resistor R. The other end of the third resistor R is connected to the collector of the third IGBT VT14. The cathode of the diode D is connected to the emitter of the third IGBT VT14 and one end of the third capacitor C d3 ; one end of the third capacitor C d3 The other end is connected to the emitter of the second IGBT VT13; When a fault occurs on the AC side and the surplus power exceeds the threshold, the third IGBT VT14 conducts, and the current flows through the third resistor R and the third capacitor C d3 , and the surplus power is dissipated through the third resistor R. At the same time, the third capacitor C d3 absorbs transient energy and charges the energy storage battery VB; When a fault occurs on the AC side and the surplus power does not exceed the threshold, the third IGBT VT14 turns off, and the current passes through the diode D and the third capacitor C d3 to charge the energy storage battery VB and suppress the rise of the DC bus voltage; When a fault occurs on the DC side, the third IGBT VT14 turns off, and the energy storage battery VB discharges through the energy storage unit. The current passes through the third capacitor C d3 and the diode D to supplement the deficit power on the DC side and maintain the stability of the bus voltage.

4. The energy storage and energy consumption device in the high-voltage DC converter valve according to claim 1, characterized in that The fully-controlled valve VC4 includes: The collector of the fourth IGBT VT15 is connected to the positive electrode of the fourth capacitor C d4 and the input end of the energy storage unit, and the emitter of the fourth IGBT VT15 is connected to the output end of the energy storage unit; When the energy storage battery VB is charged, the energy storage battery VB charges the fourth capacitor C through the inductor L and absorbs the surplus power; d4 ​ When the energy storage battery VB discharges, the fourth capacitor C d4 discharges to the energy storage battery VB through the inductor L to supplement the deficit power; When operating normally, the fourth IGBT VT15 conducts, and the energy storage unit maintains voltage balance through the fourth capacitor C d4 ; When it is detected that the DC bus current exceeds the preset safety threshold or a short-circuit fault occurs, the fourth IGBT VT15 immediately turns off, cutting off the connection between the energy storage unit and the main circuit to avoid reverse energy impact.

5. The energy storage and energy consumption device in the HVDC converter valve according to claim 4, characterized in that The energy storage unit includes: The energy storage unit is composed of a bidirectional buck-boost circuit, and the bidirectional buck-boost circuit includes a fifth IGBT VT16, a sixth IGBT VT17, an inductor L, and an energy storage battery VB; The collector of the fifth IGBT VT16 is connected to the fourth capacitor C d4 , and the emitter is connected to the collector of the sixth IGBT VT17 and one end of the inductor L; The emitter of the sixth IGBT VT17 is connected to the negative electrode of the energy storage battery VB, and the positive electrode of the energy storage battery VB is connected to the other end of the inductor L; The fourth capacitor C d4 is connected to the negative electrode of the energy storage battery VB; When it is detected that the DC bus current exceeds the preset safety threshold or a short - circuit fault occurs, the fourth IGBT VT15 is immediately turned off, and at the same time, the fifth IGBT VT16 and the sixth IGBT VT17 are forced to turn off, so that the energy storage battery VB and the fourth capacitor C d4 enter the isolation state.

6. The energy storage and energy consumption device in the HVDC converter valve according to claim 5, characterized in that The bidirectional buck-boost circuit operates in the following modes, including: In the charging mode, the fifth IGBT VT16 remains off, and the sixth IGBT VT17 conducts according to the PWM signal. The current flows out from the positive electrode of the energy storage battery VB, and based on the inductor L, the low-voltage energy of the energy storage battery VB is converted into the high-voltage side energy of the fourth capacitor C d4 for boost charging; Discharge mode, the sixth IGBT VT17 remains off, the fifth IGBT VT16 conducts according to the PWM signal, and the current flows out from the fourth capacitor C d4 Based on the inductor L, the high-voltage energy of the fourth capacitor C d4 is converted into the low-voltage side energy of the energy storage battery VB for step-down discharge; Standby mode, both the fifth IGBT VT16 and the sixth IGBT VT17 are turned off, the fourth IGBT VT15 remains conducting, and the energy storage battery VB is connected in parallel to the main circuit through the fourth IGBT VT15, causing the voltage across the fourth capacitor C d4 to be synchronized with the DC bus voltage. d4 ​ 7. The energy storage and energy consumption device in the high-voltage DC converter valve according to claim 1, characterized in that, The fully-controlled valve VC2 includes: The collector of the first IGBT VT12 is connected to the input end of the commutation branch, and the emitter is connected to the output end of the commutation branch. The second resistor-capacitor branch is composed of the second capacitor C d2 and the second resistor R d2 in series and is connected in parallel across both ends of the first IGBT VT12; During normal operation or commutation, the first IGBT VT12 conducts, and the current flows through the commutation branch to complete commutation; When the commutation branch is turned off, the first IGBT VT12 is controlled to turn off, and the second capacitor C d2 absorbs the transient voltage energy across the first IGBT VT12, and the second resistor R d2 limits the charging and discharging current of the capacitor, suppresses voltage spikes and reduces switching losses.

8. The energy storage and energy consumption device in the high-voltage DC converter valve according to claim 1, characterized in that The semi-controlled valve VC1 and the semi-controlled valve VC5 include: In the semi-controlled valve VC1, the first thyristor VT11 bears a reverse voltage during commutation. The first resistor-capacitor branch provides a reverse voltage recovery time for the first thyristor VT11 and absorbs the commutation overvoltage through the first capacitor C d1 at the same time; In the semi-controlled valve VC5, the second thyristor VT18 bears a reverse voltage after the energy storage and dissipation branch is turned off, and the third resistor-capacitor branch provides a reverse voltage recovery time for the second thyristor VT18 and suppresses voltage spikes through the fifth capacitor C d5 at the same time; When operating normally, the first thyristor VT11 and the second thyristor VT18 remain conducting, and the current flows through the commutation branch to complete commutation; When a fault occurs, the first thyristor VT11 and the second thyristor VT18 turn off, and the current transfers to the energy storage and energy consumption branch.

9. A high-voltage DC converter valve internal energy storage and energy consumption system, characterized in that The system includes: The system contains several SM sub-modules, and the SM sub-modules contain a commutation branch and an energy storage and energy consumption branch; During the normal commutation process, the commutation branches of all the SM sub-modules receive synchronous trigger signals to form a parallel current path; The commutation branches of each SM sub-module ensure balanced voltage distribution through an equalizing control strategy. When a certain arm needs to commutate, a commutation instruction is sent to the target SM sub-module to turn off the commutation branch that needs to commutate, and the energy storage and energy consumption branch is triggered to transfer the current to the energy storage and energy consumption branch of the target SM sub-module; The commutation branches of the remaining non-commutating SM sub-modules remain conducting to maintain the overall current continuity of the system; During normal operation, the commutation branches of each SM sub-module evenly divide the load current and achieve current sharing based on current closed-loop control. When a single SM sub-module exits due to a fault, the remaining SM sub-modules increase the conduction ratio to compensate for the power gap of the faulty SM sub-module; All the SM sub-modules are interconnected through a communication bus to exchange voltage, current, and switch state information in real time.

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