A high-voltage direct current converter valve internal energy storage and consumption device and system

Abstract

The present invention relates to the field of high-voltage direct current (HVDC) power transmission technology, and in particular to a HVDC converter valve internal energy storage and consumption device and system, the device comprising: a commutation branch and an energy storage and consumption branch connected in parallel; the commutation branch is composed of a first half-controlled valve and a first fully-controlled valve connected in series, the first half-controlled valve being composed of a first thyristor connected in parallel with a first resistor-capacitor branch, and the first fully-controlled valve being composed of a first insulating tube connected in parallel with a second resistor-capacitor branch; the energy storage and consumption branch is composed of a second fully-controlled valve, a third fully-controlled valve, and a second half-controlled valve connected in series in sequence, the second fully-controlled valve comprising a second insulating tube, a third insulating tube, a diode, a third resistor, and a third capacitor, the third fully-controlled valve comprising a fourth insulating tube, a fourth capacitor, and an energy storage unit, and the second half-controlled valve being composed of a second thyristor connected in parallel with a third resistor-capacitor branch. The present invention effectively addresses the defects of traditional power grid commutation systems, such as a high risk of commutation failure and insufficient power fluctuation regulation capabilities.

Description

Technical Field

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

[0002] In high-voltage direct current (HVDC) transmission systems, commutation failure is a core problem that has long been faced by traditional grid-commutated converters (LCC-HVDC). This problem is very likely to occur when a fault occurs in the receiving grid, leading to instantaneous or continuous power transmission interruptions, accompanied by problems such as overcurrent shocks and surges in reactive power demand. In severe cases, it can trigger a chain reaction of multiple DC circuits. The root cause is that the thyristor devices fail to reliably shut down and restore their forward blocking capability during the commutation process.

[0003] In the existing technology, although commutation failure can be partially alleviated by enhancing the strength of the AC system, optimizing the thyristor trigger angle or configuring a resistor-capacitor snubber circuit, there are significant limitations. Such methods only target single fault scenarios (such as commutation failure or power fluctuation) and lack the coordinated 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 solutions of flexible DC (such as MMC sub-module energy storage) are difficult to be compatible with the thyristor topology of LCC-HVDC, resulting in a contradiction between economy and adaptability; the thyristor shutdown recovery time and system response speed are not well matched, further exacerbating the risk of failure.

[0004] The information disclosed in this background technology 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 any form of suggestion that the information constitutes the prior art known to those skilled in the art. Summary of the Invention

[0005] The present invention provides a high-voltage direct current converter valve internal energy storage and energy consumption device and system, which can effectively solve the problems in the background technology.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A high-voltage direct current converter valve internal energy storage and consumption device, comprising:

[0008] It consists of a commutation branch and an energy storage and consumption branch connected in parallel;

[0009] The commutation branch is composed of a half-controlled valve VC1 and a full-controlled valve VC2 connected in series. The half-controlled valve VC1 is composed of a first thyristor VT11 connected in parallel with a first resistor-capacitor branch. The full-controlled valve VC2 is composed of a first IGBTVT12 connected in parallel with a second resistor-capacitor branch.

[0010] The energy storage and energy consumption branch is composed of a full-control valve VC3, a full-control valve VC4 and a half-control valve VC5 in series. The full-control valve VC3 includes a second IGBTVT13, a third IGBTVT14, a diode D, a third resistor R and a third capacitor C. d3 The fully controlled valve VC4 includes a fourth IGBTVT15, a fourth capacitor C d4 And energy storage unit, the half-controlled valve VC5 is composed of a second thyristor VT18 in parallel with a third resistance-capacitance branch.

[0011] Furthermore, the first resistance-capacitance branch, the second resistance-capacitance branch, and the third resistance-capacitance branch include:

[0012] The first resistance-capacitance branch is a first capacitor C d1 and the first resistor R d1 In series, in the first resistance-capacitance branch, the first capacitor C d1 The capacitance value of the first resistor R d1 The resistance matching configuration provides a reverse voltage recovery time for the first thyristor VT11 when the commutation branch is turned off;

[0013] The second resistance-capacitance branch is a second capacitor C d2 and the second resistor R d2 In series, the second capacitor C d2 The capacitance of the second resistor R d2 The resistance matching configuration suppresses voltage spikes and reduces switching losses when the first IGBTVT12 is turned off;

[0014] The third resistance-capacitance branch is a fifth capacitor C d5 and the fourth resistor R d5 In series, the third RC branch, the fifth capacitor C d5 The capacitance of the fourth resistor R d5 The resistance matching configuration provides reverse voltage recovery time and suppresses commutation overvoltage when the second thyristor VT18 of the half-controlled valve VC5 is turned off.

[0015] Furthermore, the full-control valve VC3 includes:

[0016] The collector of the second IGBTVT13 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 IGBTVT14, and the cathode of the diode D is connected to the emitter of the third IGBTVT14 and the third capacitor C d3 One end of the third capacitor C d3 The other end is connected to the emitter of the second IGBTVT13;

[0017] When a fault occurs on the AC side and the surplus power exceeds the threshold, the third IGBTVT14 is turned on, and current flows through the third resistor R and the third capacitor C. d3 , the surplus power is dissipated through the third resistor R, while the third capacitor C d3 Absorb transient energy and store it in battery V B Charge;

[0018] When a fault occurs on the AC side and the surplus power does not exceed the threshold, the third IGBTVT14 is turned off, and the current flows through the diode D and the third capacitor C. d3 The energy storage battery V B Charging, suppressing the rise of DC bus voltage;

[0019] When a fault occurs on the DC side, the third IGBTVT14 is turned off and the energy storage battery V B The energy storage unit is discharged, and the current flows through the third capacitor C d3 The diode D supplements the missing power to the DC side to maintain the bus voltage stable.

[0020] Furthermore, the full-control valve VC4 includes:

[0021] The collector of the fourth IGBTVT15 is connected to the fourth capacitor C d4 and the input end of the energy storage unit, and the emitter of the fourth IGBTVT15 is connected to the output end of the energy storage unit;

[0022] When the energy storage battery V B When charging, the energy storage battery V B Through the inductor L to the fourth capacitor C d4 Charging, absorbing surplus power;

[0023] When the energy storage battery V B When discharging, the fourth capacitor C d4 The energy storage battery V is supplied through the inductor L B Discharge to supplement the missing power;

[0024] During normal operation, the fourth IGBTVT15 is turned on, and the energy storage unit is connected to the fourth capacitor C d4 Maintain voltage balance;

[0025] When it is detected that the DC bus current exceeds a preset safety threshold or a short circuit fault occurs, the fourth IGBTVT15 is immediately turned off, cutting off the connection between the energy storage unit and the main circuit to avoid energy reverse impact.

[0026] Furthermore, the energy storage unit includes:

[0027] The energy storage unit is composed of a bidirectional buck-boost circuit, which includes a fifth IGBTVT16, a sixth IGBTVT17, an inductor L and an energy storage battery V B ;

[0028] The collector of the fifth IGBTVT16 is connected to the fourth capacitor C d4 , the emitter is connected to the collector of the sixth IGBTVT17 and one end of the inductor L;

[0029] The emitter of the sixth IGBTVT17 is connected to the energy storage battery V B The negative electrode of the energy storage battery V B The positive electrode is connected to the other end of the inductor L;

[0030] The fourth capacitor C d4 Connect the energy storage battery V B The negative electrode;

[0031] When it is detected that the DC bus current exceeds the preset safety threshold or a short circuit fault occurs, the fourth IGBTVT15 is immediately turned off, and the fifth IGBTVT16 and the sixth IGBTVT17 are forced to turn off, so that the energy storage battery V B and the fourth capacitor C d4 Enter isolation.

[0032] Furthermore, the bidirectional buck-boost circuit operates in the following modes, including:

[0033] In charging mode, the fifth IGBTVT16 remains off, the sixth IGBTVT17 is turned on according to the PWM signal, and the current flows from the energy storage battery V B The positive electrode flows out, based on the inductance L, the energy storage battery V B The low voltage energy is converted into the fourth capacitor C d4 The high-voltage side energy is used for boost charging;

[0034] In the discharge mode, the sixth IGBTVT17 is kept off, the fifth IGBTVT16 is turned on according to the PWM signal, and the current flows from the fourth capacitor C d4 outflow, based on the inductor L, the fourth capacitor C d4 The high voltage energy is converted into the energy storage battery V B The low-voltage side energy is discharged at a reduced voltage;

[0035] In standby mode, the fifth IGBTVT16 and the sixth IGBTVT17 are both turned off, the fourth IGBTVT15 remains on, and the energy storage battery VB With the fourth capacitor C d4 The fourth IGBTVT15 is connected in parallel to the main circuit, so that the fourth capacitor C d4 The voltage at both ends is synchronized with the DC bus voltage.

[0036] Furthermore, the full-control valve VC2 includes:

[0037] The collector of the first IGBTVT12 is connected to the input end of the commutation branch, the emitter is connected to the output end of the commutation branch, and the second resistance-capacitance branch is connected to the second capacitor C d2 and the second resistor R d2 are connected in series and in parallel to both ends of the first IGBTVT12;

[0038] During normal operation or commutation, the first IGBTVT12 is turned on, and current flows through the commutation branch to complete commutation;

[0039] When the commutation branch is turned off, the first IGBTVT12 is controlled to be turned off, and the second capacitor C d2 Absorb the transient voltage energy across the first IGBTVT12, the second resistor R d2 Limiting capacitor charge and discharge currents suppresses voltage spikes and reduces switching losses.

[0040] Furthermore, the half-controlled valve VC1 and the half-controlled valve VC5 include:

[0041] In the semi-controlled valve VC1, the first thyristor VT11 is subjected to reverse voltage during commutation, and the first RC branch provides reverse voltage recovery time for the first thyristor VT11. d1 Absorb commutation overvoltage;

[0042] In the semi-controlled valve VC5, the second thyristor VT18 is subjected to reverse voltage after the energy storage and energy consumption branch is turned off. The third RC branch provides reverse voltage recovery time for the second thyristor VT18. At the same time, the fifth capacitor C d5 Suppress voltage spikes;

[0043] During normal operation, the first thyristor VT11 and the second thyristor VT18 remain turned on, and current flows through the commutation branch to complete commutation;

[0044] 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 energy consumption branch.

[0045] A high-voltage direct current converter valve internal energy storage and consumption system, the system comprising:

[0046] The system comprises a plurality of SM submodules, wherein the SM submodule comprises a commutation branch and an energy storage and consumption branch;

[0047] During normal commutation, the commutation branches of all the SM submodules receive a synchronous trigger signal to form a parallel current path;

[0048] The commutation branches of each SM submodule ensure balanced voltage distribution through a voltage-sharing control strategy. When a bridge arm needs to be commutated, a commutation instruction is sent to the target SM submodule to shut down the commutation branch that needs to be commutated, and trigger the energy storage and consumption branch to transfer current to the energy storage and consumption branch of the target SM submodule;

[0049] The commutation branches of the remaining non-commutated SM submodules remain conductive to maintain overall system current continuity;

[0050] During normal operation, the commutation branches of each SM submodule evenly share the load current, and current sharing is achieved based on current closed-loop control. When a single SM submodule exits due to a fault, the remaining SM submodules increase the conduction ratio to compensate for the power gap of the faulty SM submodule;

[0051] All the SM submodules are interconnected via a communication bus to exchange voltage, current and switch status information in real time.

[0052] Based on the above content, a method for controlling energy storage and consumption in the valve of a high-voltage DC converter can also be developed. The main content is to control the conduction of the half-controlled valve and the full-controlled valve in the commutation branch, so that the current flows through the commutation branch and performs the commutation operation between the bridge arms; during the commutation process, the voltage spike is suppressed according to the resistance and capacitance branch of the commutation branch, and the reverse shutdown condition is provided for the thyristor in the half-controlled valve; the DC bus voltage and power status are monitored in real time, and when a power surplus on the AC side or a power shortage on the DC side is detected, the full-controlled valve of the commutation branch is turned off and the half-controlled valve of the energy storage and consumption branch is triggered. , switching the current path to the energy storage and consumption branch; during the current switching process, delaying the shutdown of the semi-controlled valve of the energy storage and consumption branch to ensure that the time for the thyristor of the commutation branch to withstand the reverse voltage meets the blocking recovery requirements; suppressing the commutation overvoltage according to the resistance and capacitance branch of the energy storage and consumption branch to prevent secondary faults; during the charging and discharging process of the energy storage and consumption branch, dynamically adjusting the energy transmission rate through the bidirectional power conversion circuit to maintain the synchronization of the capacitor voltage and the DC bus; in the fault recovery stage, gradually reducing the power output of the energy storage and consumption branch, smoothly switching to the normal commutation mode.

[0053] The technical solution of the present invention can achieve the following technical effects:

[0054] Through the dynamic switching and hierarchical control of the embedded energy storage and energy consumption branches in the valve, bidirectional power smoothing is achieved while suppressing commutation failure. It is compatible with the traditional LCC-HVDC structure and does not require external devices, thereby improving the system reliability, economy and dynamic response capabilities.

[0055] The above description is only an overview of the technical solution of the present application. In order to more clearly understand the technical means of the present application, it can be implemented in accordance with the contents of the specification. In order to make the above and other purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are listed below. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0057] Figure 1 This is the topological structure diagram of the energy storage and consumption system in the valve;

[0058] Figure 2 Detailed circuit diagram of the commutation branch and the energy storage and consumption branch;

[0059] Figure 3 This is a structural diagram of an energy storage and consumption system in a high-voltage DC converter valve. DETAILED DESCRIPTION

[0060] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0061] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which this invention pertains. The terms used in this specification are for the purpose of describing specific embodiments only and are not intended to limit the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0062] Embodiment 1;

[0063] like Figure 1 、 Figure 2 As shown, the present application provides a high-voltage direct current converter valve internal energy storage and energy consumption device, comprising:

[0064] It consists of a commutation branch and an energy storage and consumption branch connected in parallel;

[0065] The commutation branch is composed of a half-controlled valve VC1 and a full-controlled valve VC2 in series. The half-controlled valve VC1 is composed of a first thyristor VT11 connected in parallel with a first resistor-capacitor branch, and the full-controlled valve VC2 is composed of a first IGBTVT12 connected in parallel with a second resistor-capacitor branch.

[0066] The energy storage and energy consumption branch is composed of a full-control valve VC3, a full-control valve VC4 and a half-control valve VC5 in series. The full-control valve VC3 includes a second IGBTVT13, a third IGBTVT14, a diode D, a third resistor R and a third capacitor C. d3 The full-control valve VC4 includes the fourth IGBTVT15, the fourth capacitor C d4 And the energy storage unit, the half-controlled valve VC5 is composed of the second thyristor VT18 in parallel with the third resistance-capacitance branch.

[0067] Specifically, the commutation branch consists of a half-controlled valve VC1 and a full-controlled valve VC2 in series, which undertakes the basic task of power commutation and fully considers the balance between commutation speed and overvoltage resistance. The half-controlled valve VC1 consists of a thyristor VT11 and a resistance-capacitance branch (C d1 、R d1 ) in parallel, the thyristor has good pressure bearing capacity and impact resistance, suitable for taking on the main commutation task; while the RC branch absorbs the voltage spike when the thyristor is turned off, provides voltage equalization function, and prevents the device from being damaged due to uneven voltage; the full-control valve VC2 adopts IGBT VT12 parallel RC branch (C d2 、R d2 ) structure. Compared with thyristors, IGBTs support higher frequency and more flexible on-off control, which enables the system to more finely control the current waveform during operation and improve system stability. The resistance-capacitance branch further improves the voltage sharing capacity of the IGBT at the switching moment; the energy storage and consumption 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 connected in series with IGBT VT13 and VT14 and resistor R, capacitor C d3 , diode D, when there is a short-term over-energy or current shock in the system, this structure can quickly release the energy in the resistor R and pass it through the capacitor C d3The filter suppresses transient fluctuations. At the same time, the diode D provides a unidirectional conduction path to ensure that the energy consumption process does not affect normal operation. VC4 integrates energy storage function. The core is a bidirectional Buck-Boost circuit, which consists of IGBT VT15, VT16, VT17, inductor L and energy storage battery VB. This structure realizes the bidirectional flow of energy. When the grid has excess energy, the system stores the electric energy in the battery in a step-down manner; when the grid needs support, it can boost the output to provide stable voltage support for the system and effectively balance the system power fluctuations. VC5 consists of thyristor VT18 and the resistor-capacitor branch (C d5 、R d5 ) is used for emergency energy consumption and safety protection. When a serious fault is detected or the energy storage unit cannot respond in time, VC5 is quickly turned on to dissipate the excess energy of the system through the resistor to prevent the voltage from rising further; the RC branch also plays a role in suppressing spikes.

[0068] The technical solution of the present invention realizes dynamic switching and hierarchical control of the embedded energy storage and energy consumption branches in the valve, achieves bidirectional power smoothing while suppressing commutation failure, is compatible with the traditional LCC-HVDC structure and does not require external devices, thereby improving system reliability, economy and dynamic response capabilities.

[0069] Specifically, the first RC branch, the second RC branch, and the third RC branch include:

[0070] The first RC branch is the first capacitor C d1 and the first resistor R d1 In series, in the first RC branch, the first capacitor C d1 The capacitance of the first resistor R d1 The resistance matching configuration provides reverse voltage recovery time for the first thyristor VT11 when the commutation branch is turned off;

[0071] The second RC branch is the second capacitor C d2 and the second resistor R d2 In series, in the second RC branch, the second capacitor C d2 The capacitance of the second resistor R d2 The resistance matching configuration suppresses the voltage spike and reduces the switching loss when the first IGBTVT12 is turned off;

[0072] The third RC branch is the fifth capacitor C d5 and the fourth resistor R d5 In series, in the third RC branch, the fifth capacitor C d5 The capacitance of the fourth resistor R d5 The resistance matching configuration provides reverse voltage recovery time and suppresses commutation overvoltage when the second thyristor VT18 of the half-controlled valve VC5 is turned off.

[0073] As a preferred embodiment of the above, the first capacitor C d1 and the first resistor R d1 The matching configuration can ensure that when the thyristor is turned off, the system can restore the voltage stably, avoiding the damage of the thyristor and other system components caused by voltage shock; capacitor C d1 It is mainly responsible for absorbing the overvoltage generated during the current mutation when the commutation branch is turned off, and providing reverse current in a short time. It plays a filtering and stabilizing role in the operation of the converter through its stored energy, slowing down voltage fluctuations. The larger the capacitance, the stronger the current impact it can withstand, and it can also more effectively suppress instantaneous voltage changes. d1 With capacitor C d1 Together they form an RC circuit, which is mainly used to control the capacitance C d1 The charge and discharge rate of the resistor determines the capacitance C d1 The discharge time, that is, the speed of energy release, can be reasonably configured to avoid excessive current fluctuations or voltage reverse peaks caused by excessive discharge of the capacitor. In the design, the first capacitor C d1 The capacitance of the first resistor R d1 The resistance of the capacitor C needs to be accurately matched. The matching configuration of the two can ensure that when the thyristor VT11 is turned off, the capacitor C d1 The speed of charge and discharge and the smoothness of current change are balanced to provide an appropriate reverse voltage recovery time. When the thyristor VT11 is turned off, the current gradually decreases and a reverse voltage is generated. If the resistor and capacitor are not matched properly, the capacitor may discharge too quickly, causing the voltage to recover too quickly, or even generate an overvoltage shock, damaging the component. On the contrary, if the discharge is too slow, the thyristor voltage recovery time may be too long, affecting the commutation efficiency. Capacitor C d1 The choice of resistor R d1 It should have an appropriate resistance value so that during the commutation shutdown process, the capacitor can release the stored energy at an appropriate speed, thereby effectively restoring the reverse voltage and avoiding the impact of overvoltage or current mutation on the system; by accurately matching the first capacitor C d1 With the first resistor R d1 The present invention can ensure that the system can smoothly restore voltage during the shutdown process of thyristor VT11, avoiding current or voltage shocks 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 shocks, and thus extends the service life of the system; the second RC branch is mainly used to suppress voltage spikes and reduce switching losses. In this branch, the capacitor C d2 and resistor R d2The configuration of the first RC branch is similar to that of the first RC branch. Both control the charge and discharge rate by accurately matching the capacitance and resistance values. The capacitance C d2 Responsible for absorbing and storing energy, resistor R d2 The difference is that the second RC branch focuses more on voltage spike suppression during the switching process. Therefore, the selection of capacitors and resistors will be optimized differently according to the switching characteristics and energy absorption requirements. The function of the third RC branch is to provide reverse voltage recovery time and suppress commutation overvoltage. Capacitor C d5 and resistor R d5 The selection of is similar to that of the first branch, which also affects the response speed and stability of the system by controlling the charge and discharge rate of the capacitor. Since the function of the third RC branch is to deal with the overvoltage during the commutation process, the selection of capacitors and resistors will be adjusted according to the specific commutation overvoltage characteristics.

[0074] More specifically, the fully controlled valve VC3 includes:

[0075] The collector of the second IGBTVT13 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 IGBTVT14, and the cathode of the diode D is connected to the emitter of the third IGBTVT14 and the third capacitor C d3 One end of the third capacitor C d3 The other end is connected to the emitter of the second IGBTVT13;

[0076] When a fault occurs on the AC side and the surplus power exceeds the threshold, the third IGBTVT14 is turned on and the current flows through the third resistor R and the third capacitor C. d3 , the surplus power is dissipated through the third resistor R, while the third capacitor C d3 Absorb transient energy and store it in battery V B Charge;

[0077] When a fault occurs on the AC side and the surplus power does not exceed the threshold, the third IGBTVT14 is turned off and the current flows through the diode D and the third capacitor C. d3 For the energy storage battery V B Charging, suppressing the rise of DC bus voltage;

[0078] When a fault occurs on the DC side, the third IGBTVT14 is turned off and the energy storage battery V B The energy storage unit discharges, and the current flows through the third capacitor C d3 And diode D supplements the missing power to the DC side to maintain the bus voltage stable.

[0079] As a preferred embodiment of the above, the HVDC converter valve internal energy storage and energy consumption device is provided with a fully controlled valve VC3, which is used to achieve dynamic management of energy and enhance system stability under different operating conditions. The fully controlled valve VC3 includes a second insulated gate bipolar transistor (second IGBTVT13), a third insulated gate bipolar transistor (third IGBTVT14), 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 IGBTVT13 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 IGBTVT14, and the cathode of the diode D is connected to the emitter of the third IGBTVT14 and the third capacitor C d3 One end of the third capacitor C d3 The other end is connected to the emitter of the second IGBTVT13, thereby forming a closed power circulation branch. The third capacitor C d3 With energy storage battery V B The parallel setting 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, it is judged that it exceeds the set threshold. In order to avoid a rapid rise in the bus voltage or accumulation of system energy, the third IGBTVT14 is driven to turn on. 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 caused by energy concentration. At the same time, the third capacitor C d3 Absorb and buffer the transient current in the circuit and transfer part of the energy to the energy storage battery V B In the process, the emergency capacity of the energy storage unit is increased; if a fault occurs on the AC side but the surplus power does not exceed the set control threshold, the third IGBTVT14 is kept in the off state, and the current path passes through the diode D and the third capacitor C d3 Flows to the energy storage battery V B , realize the normal charging process of the energy storage battery, and at the same time the third capacitor C d3 It can inhibit the rapid rise of DC bus voltage, and avoid excessive bus voltage fluctuations that may cause system instability or false triggering of protection actions. When a fault occurs on the DC side, such as voltage drop, sudden load increase or power outage, the control system turns off the third IGBTVT14 and controls the energy storage battery V B Release the stored energy to compensate for the power gap on the DC side. During this process, the energy storage battery V B The output current passes through the third capacitor C d3 and diode D output to the DC side, the third capacitor C d3It provides necessary voltage buffering for the output current and improves the stability of power transmission. The diode D ensures that the current flows unidirectionally to the load, preventing the voltage backflow 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 realize the reasonable distribution and conversion of energy in different working scenarios through the linkage of key components such as the second IGBT, the third IGBT, the resistor-capacitor network and the diode, thereby improving the anti-interference ability of the converter under fault conditions and the overall operation safety of the system. The capacitor C d3 The specific parameters of the resistor R can be engineered to match the design capacity of the power module, the bus voltage level, the response speed of the energy storage system, and other requirements to ensure the coordinated cooperation of energy absorption, dissipation, and output under various operating conditions.

[0080] Specifically, the fully controlled valve VC4 includes:

[0081] The collector of the fourth IGBTVT15 is connected to the fourth capacitor C d4 The positive electrode and the input end of the energy storage unit, the emitter of the fourth IGBTVT15 is connected to the output end of the energy storage unit;

[0082] When the energy storage battery V B When charging, the energy storage battery V B Through the inductor L to the fourth capacitor C d4 Charging, absorbing surplus power;

[0083] When the energy storage battery V B When discharging, the fourth capacitor C d4 Through the inductor L to the energy storage battery V B Discharge to supplement the missing power;

[0084] When operating normally, the fourth IGBTVT15 is turned on, and the energy storage unit is connected to the fourth capacitor C d4 Maintain voltage balance;

[0085] When it is detected that the DC bus current exceeds the preset safety threshold or a short circuit fault occurs, the fourth IGBTVT15 is immediately turned off, cutting off the connection between the energy storage unit and the main circuit to avoid energy reverse impact.

[0086] As a preferred embodiment of the above, the HVDC converter valve internal energy storage and energy consumption device further includes a fully controlled valve VC4, which is used to achieve bidirectional energy flow control and safe isolation between the energy storage unit and the main circuit. The fully controlled valve VC4 includes a fourth insulated gate bipolar transistor (fourth IGBTVT15), a fourth capacitor C d4 , inductor L and energy storage battery V B In terms of component connection relationship, the collector of the fourth IGBTVT15 is connected to the fourth capacitor Cd4 The positive electrode and the input end of the energy storage unit, the emitter of the fourth IGBTVT15 is connected to the output end of the energy storage unit, thereby forming a current control path, the fourth capacitor C d4 With energy storage battery V B The inductor L is connected between them to suppress current mutation during the charging and discharging process, thereby improving system stability and power transmission efficiency. Under normal operating conditions, when the DC system is working stably and the load and power supply are balanced, the control unit drives the fourth IGBTVT15 to turn on, so that the energy storage unit and the fourth capacitor C d4 Maintain stable connection, at this time the energy storage unit is in the fourth capacitor C d4 With the support of , it can dynamically buffer the voltage fluctuation, realize voltage balance control, and improve the power quality and operation stability of the converter; when there is excess power on the AC side, the control system monitors the energy storage battery V B In the charging state, start the energy storage process, the energy storage battery V B Through the inductor L to the fourth capacitor C d4 During charging, the inductor L limits the rate of change of current during the charging process, preventing large current shocks from damaging the device. The fourth capacitor C d4 Absorb excess electrical energy and temporarily store it, thereby improving the power buffering capacity of the energy storage unit, enabling the system to respond quickly to sudden load changes and prevent abnormal increases in bus voltage; when a power gap appears on the DC side, it enters the discharge mode, and the control unit triggers the energy storage battery V according to load demand. B Discharge, at this time, the fourth capacitor C d4 Through the inductor L to the energy storage battery V B The stored energy is released to replenish the required power. The inductor L also plays a current limiting protection role during the discharge process, ensuring the safe operation between the battery and the main circuit and improving the continuity of energy supply. In order to enhance the 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 instruction is issued to turn off the fourth IGBTVT15. By turning off the IGBT device, the connection between the energy storage unit and the main circuit is quickly cut off, avoiding the energy storage battery from continuously supplying energy to the fault point, preventing the energy reverse impact from causing system damage or local overheating, thereby effectively protecting the safety of the energy storage device and the entire DC converter system. In this embodiment, by setting the fourth IGBTVT15 and the capacitor C d4 The coordinated control of components such as , inductor L, etc. can not only realize efficient charging and discharging of the energy storage battery, but also actively switch the power supply and isolation mode according to the operating status, ensuring that stable and reliable power support can be provided under normal and fault conditions. The parameter configuration of the above components can be optimized and matched according to factors such as system design capacity, voltage level and protection strategy to meet the usage requirements in different engineering scenarios.

[0087] More specifically, the energy storage unit includes:

[0088] The energy storage unit is composed of a bidirectional buck-boost circuit, which includes a fifth IGBTVT16, a sixth IGBTVT17, an inductor L and an energy storage battery V B ;

[0089] The collector of the fifth IGBTVT16 is connected to the fourth capacitor C d4 , the emitter is connected to the collector of the sixth IGBTVT17 and one end of the inductor L;

[0090] The emitter of the sixth IGBTVT17 is connected to the energy storage battery V B The negative electrode of the energy storage battery V B The positive electrode is connected to the other end of the inductor L;

[0091] The fourth capacitor C d4 Connect the energy storage battery V B The negative electrode;

[0092] When it is detected that the DC bus current exceeds the preset safety threshold or a short circuit fault occurs, the fourth IGBTVT15 is immediately turned off, and the fifth IGBTVT16 and the sixth IGBTVT17 are forced to turn off, so that the energy storage battery V B and the fourth capacitor C d4 Enter isolation.

[0093] As a preferred embodiment of the above, the energy storage unit adopts a bidirectional buck-boost circuit structure to achieve the energy storage battery V B The energy storage unit is mainly composed of a fifth insulated gate bipolar transistor (fifth IGBTVT16), a sixth insulated gate bipolar transistor (sixth IGBTVT17), an inductor L, an energy storage battery V B And the fourth capacitor C d4 Composition; From the perspective of electrical connection, the fourth capacitor C d4 Connected to the input side of the energy storage unit, and connected to the collector of the fifth IGBTVT16 through a line, the emitter of the fifth IGBTVT16 is connected to the collector of the sixth IGBTVT17, and is also connected to one end of the inductor L to form a main power transmission path. The emitter of the sixth IGBTVT17 is further connected to the energy storage battery V B The negative electrode of the energy storage battery V B The positive electrode of the inductor is connected to the circuit through the other end of the inductor L. The entire energy storage unit uses the inductor L as the core coupling element, and controls the bidirectional flow of electric energy through the two-stage IGBT switching device to achieve adaptive conversion between boost and buck. BDuring the charging phase, when power surplus is detected and the bus voltage is high, the fifth IGBTVT16 and the sixth IGBTVT17 are controlled to conduct alternately according to a certain PWM control strategy to construct a buck mode. In this mode, the electric energy from the main circuit is transferred to the fourth capacitor C d4 Enters the energy storage unit, passes through the fifth IGBTVT16, inductor L and the sixth IGBTVT17, and finally enters the energy storage battery V B In this process, the inductor L plays the role of temporary energy storage and current buffering, ensuring a smooth battery charging process and avoiding damage to the battery caused by large current; in the energy storage battery discharge stage, that is, when the DC system load increases or the DC bus voltage drops, the fifth IGBTVT16 and the sixth IGBTVT17 operate in boost mode under the drive of the control system, and the energy storage battery V B Energy is released, and after being stored in the inductor L, it is released to the main circuit through the switch control. The output voltage is increased by means of the magnetic energy conversion of the inductor to meet the bus power supply demand. This process effectively ensures the power supply stability of the system under conditions such as voltage drop and sudden load increase. In order to enhance the safety under fault conditions, when the DC bus current exceeds the preset safety threshold or a serious fault such as a short circuit occurs, a control signal is immediately issued to make the fourth IGBTVT15 enter the shutdown state, quickly cutting off the direct connection between the energy storage unit and the main circuit. At the same time, the control system synchronously shuts down the fifth IGBTVT16 and the sixth IGBTVT17, forcibly stopping the energy storage battery V B Energy interaction with other components in the circuit ensures that the fourth capacitor C d4 It is isolated from the energy storage battery to prevent reverse energy flow from causing damage to the main circuit or energy storage module, thereby improving the electrical safety and fault suppression capabilities of the entire converter system.

[0094] More specifically, the bidirectional buck-boost circuit operates in the following modes:

[0095] In charging mode, the fifth IGBTVT16 remains off, and the sixth IGBTVT17 is turned on according to the PWM signal, and the current flows from the energy storage battery V B The positive electrode flows out, based on the inductor L, the energy storage battery V B The low voltage energy is converted into the fourth capacitor C d4 The high-voltage side energy is used for boost charging;

[0096] In discharge mode, the sixth IGBTVT17 remains off, the fifth IGBTVT16 is turned on according to the PWM signal, and the current flows from the fourth capacitor C d4 outflow, based on the inductor L, the fourth capacitor C d4 The high voltage energy is converted into energy storage battery V B The low-voltage side energy is discharged at a reduced voltage;

[0097] In standby mode, the fifth IGBTVT16 and the sixth IGBTVT17 are both turned off, the fourth IGBTVT15 remains on, and the energy storage battery V B and the fourth capacitor C d4 The fourth capacitor C is connected in parallel to the main circuit through the fourth IGBTVT15. d4 The voltage at both ends is synchronized with the DC bus voltage.

[0098] As a preferred embodiment of the above, in the charging mode, it is detected that the energy storage battery V B The low voltage energy in the capacitor is converted to a higher voltage to supplement the fourth capacitor C d4 At this time, the fifth IGBTVT16 is kept off to prevent the power from the main circuit from flowing to the energy storage battery; at the same time, the sixth IGBTVT17 is turned on according to the PWM signal, adjusting the switching frequency and conduction time to accurately control the current flow; the current flows from the energy storage battery V B The current flows out of the positive electrode, passes through the sixth IGBTVT17, and flows to the inductor L. The inductor L acts as an energy storage element, temporarily storing the low-voltage electric energy in the energy storage battery through its magnetic field and releasing it at the appropriate time. In this process, the role of the inductor L is to convert the direction of the current and the energy characteristics, so that the energy storage battery V B The low voltage energy is converted into a higher voltage through the inductor boost 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 instantaneous power supply. In this mode, when the current passes through the inductor L, the increase or decrease of the current is affected by the PWM control signal, so the charging rate can be accurately adjusted to avoid current mutations causing damage to the battery or circuit; in the discharge mode, if an increase in load demand or a drop in DC bus voltage is detected, the stored high-voltage energy needs to be released to supplement the power demand of the system. At this time, the sixth IGBTVT17 remains off, cutting off the energy storage battery V B The fifth IGBTVT16 is turned on according to the PWM signal to realize the reverse flow of current; the current flows from the fourth capacitor C d4 The current flows out and enters the inductor L through the conductive fifth IGBTVT16. Under the action of the inductor L, the high voltage energy stored in the capacitor is converted into a lower voltage to adapt to the energy storage battery V B The inductor L plays the role of energy transfer and current regulation. By gradually releasing the stored energy, it ensures that the energy flows into the energy storage battery at an appropriate rate. The key to this process is the reversal of the current flow. By controlling the on-time and switching frequency of the fifth IGBTVT16, the discharge rate can be flexibly adjusted to make the energy storage battery V BIt can obtain the required low-voltage charging to ensure efficient and safe discharge of the battery; in standby mode, when no charging or discharging is required, the fifth IGBTVT16 and the sixth IGBTVT17 are kept in the off state. At this time, the energy storage battery V B and the fourth capacitor C d4 Through the fourth IGBTVT15 connection, and in parallel to the main circuit, this design ensures that the energy storage unit can keep synchronization with the main circuit when not charging or discharging, and does not affect the normal operation of the main circuit. In this mode, the fourth capacitor C d4 The voltage across the two ends will be synchronized with the DC bus voltage, so that the fourth capacitor C d4 It can stabilize the voltage, avoid excessive fluctuations, and maintain the system's power stability. The on-state of the fourth IGBTVT15 ensures the safe parallel connection of the capacitor and battery with 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 without the need for charging or discharging, ensuring that it can respond quickly when the load changes and switch to charging or discharging mode, thereby achieving efficient energy management and system protection.

[0099] More specifically, the fully controlled valve VC2 includes:

[0100] The collector of the first IGBTVT12 is connected to the input end of the commutation branch, the emitter is connected to the output end of the commutation branch, and the second resistance-capacitance branch is connected to the second capacitor C d2 and the second resistor R d2 They are connected in series and in parallel to both ends of the first IGBTVT12;

[0101] During normal operation or commutation, the first IGBTVT12 is turned on, and the current flows through the commutation branch to complete the commutation;

[0102] When the commutation branch is turned off, the first IGBTVT12 is controlled to turn off, and the second capacitor C d2 Absorb the transient voltage energy across the first IGBTVT12, the second resistor R d2 Limiting capacitor charge and discharge currents suppresses voltage spikes and reduces switching losses.

[0103] As a preferred embodiment of the above, during normal operation or commutation, the first IGBTVT12 is turned on to realize the operation of current flowing through the commutation branch. At this time, the collector of the first IGBTVT12 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 power conversion. The commutation branch is in the on 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 resistance-capacitance branch is the second capacitor C d2 and the second resistor Rd2 The two ends of the first IGBTVT12 are connected in parallel, and the second capacitor C d2 The function of the second resistor R is to buffer voltage fluctuations and absorb transient voltages caused by current fluctuations to avoid damage to IGBT or other circuit components caused by high-frequency voltage fluctuations. d2 With capacitor C d2 Together they control the charge and discharge process, limit the charge and discharge current of the capacitor, ensure a smooth charge and discharge process, and avoid losses caused by excessive current. When the commutation branch is turned off, the first IGBTVT12 is controlled to turn off, that is, to close the conduction state, to prevent the current from continuing to flow through the commutation branch. At this time, the second capacitor C d2 Absorb the transient voltage energy from both ends of the first IGBTVT12. Due to the sudden stop of current during the commutation process, a transient high voltage peak may be generated at both ends of the first IGBTVT12. These high voltage peaks may cause damage to the IGBT or other components of the system. At this time, the second capacitor C d2 It will quickly absorb these transient voltages and slow down the voltage rise through its own energy storage capacity to avoid the occurrence of voltage spikes. In order to ensure that the charging and discharging process does not cause excessive current fluctuations or damage the circuit, the second resistor R d2 It plays the role of limiting the charging and discharging current of the capacitor. The existence of the resistor can effectively slow down the charging and discharging rate of the capacitor, avoid excessive current, thereby suppressing switching loss and ensuring stable operation of the system. In this case, the selection of the resistor value is crucial. A reasonable resistance 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 The second RC branch can effectively suppress voltage spikes and reduce switching losses. The second capacitor C d2 By absorbing the instantaneous voltage generated when the commutation branch is turned off, the high-frequency noise and voltage fluctuation in the system are reduced; and the second resistor R d2 By limiting the charge and discharge rate of the capacitor, it ensures that the current does not change drastically, thereby reducing the switching loss caused by current fluctuations.

[0104] More specifically, the half-control valve VC1 and the half-control valve VC5 include:

[0105] In the half-controlled valve VC1, the first thyristor VT11 is subjected to reverse voltage during the commutation period. The first RC branch provides reverse voltage recovery time for the first thyristor VT11. At the same time, the first capacitor C d1 Absorb commutation overvoltage;

[0106] In the semi-controlled valve VC5, the second thyristor VT18 is subjected to reverse voltage after the energy storage and energy consumption branch is turned off. The third RC branch provides reverse voltage recovery time for the second thyristor VT18. At the same time, the fifth capacitor C d5 Suppress voltage spikes;

[0107] During normal operation, the first thyristor VT11 and the second thyristor VT18 remain turned on, and the current flows through the commutation branch to complete the phase change;

[0108] 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 consumption branch.

[0109] As a preferred embodiment of the above, the semi-controlled valve VC1 includes a first thyristor VT11 and a first RC branch connected in parallel at both ends thereof. The branch is a first capacitor C d1 and the first resistor R d1 The first thyristor VT11 is connected in series. During the commutation process, the first thyristor VT11 serves as the main conduction device to complete the AC commutation. When the commutation branch is turned off, the first thyristor VT11 is turned off and withstands the reverse voltage from the line. At this time, the first RC branch plays an important role. The first capacitor C d1 Absorb the commutation overvoltage generated at the moment of shutdown to prevent the peak voltage from damaging the device; at the same time, the first resistor R d1 Limit the capacitor charge and discharge current to ensure that 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, so that it can reliably enter the blocking state. In typical operating scenarios, such as when switching from the operating state to the energy transfer stage, the first thyristor VT11 needs to be turned off quickly, C d1 Timely absorb the voltage mutation caused by commutation, and at the same time through R d1 Smooth release to achieve voltage recovery control; the semi-controlled valve VC5 includes a second thyristor VT18 and a third resistor-capacitor branch, which is connected by a fifth capacitor C d5 and the fourth resistor R d5 The second thyristor VT18 is composed of two parts in series. As the main control device in the energy storage and energy consumption branch, it is controlled in the state of system failure or energy feedback. After the energy storage and energy consumption branch is turned off, the second thyristor VT18 needs to bear the reverse voltage that may appear in the line. At this time, the fifth capacitor C d5 Absorb overvoltage and suppress reverse voltage fluctuations, the fourth resistor R d5 Then for C d5The charging and discharging process is limited and controlled to ensure that the capacitor releases energy smoothly and avoids the voltage spike from being transmitted to the main circuit again. The overall third RC branch ensures that the second thyristor VT18 has sufficient reverse voltage recovery time to safely complete the phase switching process. For example, when a bus abnormality is detected or it is necessary to quickly transfer to the energy storage branch for energy transfer, the second thyristor VT18 is turned off at the switching moment, and the third RC branch immediately provides a reverse bias voltage to reliably block it and absorb the commutation impact energy; in normal operation, the first thyristor VT11 and the second thyristor VT18 remain in the on 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 RC branch is in an inactive state. The branch does not participate in the main energy conversion process and is only in a static standby state. The current relies on the thyristor conduction channel to flow stably to complete the normal energy commutation. Once an abnormal situation such as DC bus overvoltage or AC side short circuit is detected, the first thyristor VT11 and the second thyristor VT18 will be quickly turned off, cutting off the original commutation path, and the current will immediately switch to the energy storage and consumption branch. The energy transfer and consumption are carried out by the subsequent full-control valve and energy storage unit. At the moment the thyristor is turned off, the resistance-capacitance branch responds in time to provide the necessary reverse voltage recovery time and overvoltage suppression channel for the first thyristor VT11 and the second thyristor VT18 respectively, ensuring safe switching of components and preventing voltage spikes from affecting system stability.

[0110] Embodiment 2:

[0111] Based on the same inventive concept as the HVDC converter valve internal energy storage and consumption device in the aforementioned embodiment, the present invention also provides a HVDC converter valve internal energy storage and consumption system, such as Figure 3 As shown, the system includes:

[0112] The system includes several SM submodules, each of which includes a commutation branch and an energy storage and consumption branch;

[0113] During normal commutation, the commutation branches of all SM submodules receive synchronous trigger signals to form parallel current paths;

[0114] The commutation branches of each SM submodule use a voltage-sharing control strategy to ensure balanced voltage distribution. When a bridge arm needs to be commutated, a commutation instruction is sent to the target SM submodule, shutting down the commutation branch that needs to be commutated, and triggering the energy storage and consumption branch to transfer current to the energy storage and consumption branch of the target SM submodule;

[0115] The commutation branches of the remaining SM submodules that are not commutated remain conductive to maintain the overall current continuity of the system;

[0116] During normal operation, the commutation branches of each SM submodule evenly share the load current, achieving current balancing based on current closed-loop control. When a single SM submodule fails, the remaining SM submodules increase their conduction ratio to compensate for the power shortfall of the faulty SM submodule.

[0117] All SM submodules are interconnected via a communication bus to exchange voltage, current and switch status information in real time.

[0118] Matching a high-voltage direct current converter valve internal energy storage and energy consumption system is also a high-voltage direct current converter valve internal energy storage and energy consumption control method, that is, controlling the half-controlled valve and the full-controlled valve in the commutation branch to conduct, so that the current flows through the commutation branch and performs the commutation operation between the bridge arms; in the commutation process, the voltage spike is suppressed according to the resistance and capacitance branch of the commutation branch, and the reverse shutdown condition is provided for the thyristor in the half-controlled valve; the DC bus voltage and power status are monitored in real time, and when a power surplus on the AC side or a power shortage on the DC side is detected, the full-controlled valve of the commutation branch is turned off to trigger the energy storage and energy consumption. The semi-controlled valve of the energy storage and consumption branch switches the current path to the energy storage and consumption branch; during the current switching process, the semi-controlled valve of the energy storage and consumption branch is delayed to close, ensuring that the time for the thyristor of the commutation branch to withstand the reverse voltage meets the blocking recovery requirements; according to the resistance and capacitance branch of the energy storage and consumption branch, the commutation overvoltage is suppressed to prevent secondary faults. During the charging and discharging process of the energy storage and consumption branch, the energy transmission rate is dynamically adjusted through the bidirectional power conversion circuit to maintain the synchronization of the capacitor voltage and the DC bus; in the fault recovery stage, the power output of the energy storage and consumption branch is gradually reduced, and it is smoothly switched to the normal commutation mode.

[0119] The above-mentioned system in the present invention can effectively realize an energy storage and energy consumption device in the valve of a high-voltage direct current converter. The technical effects that can be achieved are as described in the above-mentioned embodiments and will not be repeated here.

[0120] Although the present application has been described with reference to specific features and embodiments thereof, it is apparent that various modifications and combinations may be made thereto without departing from the spirit and scope of the present application. Accordingly, this specification and drawings are merely illustrative of the present application as defined herein and are deemed to cover any and all modifications, variations, combinations or equivalents within the scope of the present application. Obviously, those skilled in the art may make various modifications and variations to the present application without departing from the scope of the present application. Thus, the present application is intended to include such modifications and variations as fall within the scope of the present application and its equivalents.

Claims

1. A high-voltage direct current converter valve internal energy storage and energy consumption device, characterized in that: include: It consists of a commutation branch and an energy storage and consumption branch connected in parallel; The commutation branch is composed of a half-controlled valve VC1 and a full-controlled valve VC2 connected in series. The half-controlled valve VC1 is composed of a first thyristor VT11 connected in parallel with a first resistor-capacitor branch. The full-controlled valve VC2 is composed of a first IGBTVT12 connected in parallel with a second resistor-capacitor branch. The energy storage and energy consumption branch is composed of a full-control valve VC3, a full-control valve VC4 and a half-control valve VC5 in series. The full-control valve VC3 includes a second IGBTVT13, a third IGBTVT14, a diode D, a third resistor R and a third capacitor C. d3 The fully controlled valve VC4 includes a fourth IGBTVT15, a fourth capacitor C d4 and energy storage unit, the semi-controlled valve VC5 is composed of a second thyristor VT18 connected in parallel with a third resistance-capacitance branch; The first resistance-capacitance branch, the second resistance-capacitance branch, and the third resistance-capacitance branch include: The first resistance-capacitance branch is a first capacitor C d1 and the first resistor R d1 In series, in the first resistance-capacitance branch, the first capacitor C d1 The capacitance value of the first resistor R d1 The resistance matching configuration provides a reverse voltage recovery time for the first thyristor VT11 when the commutation branch is turned off; The second resistance-capacitance branch is a second capacitor C d2 and the second resistor R d2 In series, the second capacitor C d2 The capacitance of the second resistor R d2 The resistance matching configuration suppresses voltage spikes and reduces switching losses when the first IGBTVT12 is turned off; The third resistance-capacitance branch is a fifth capacitor C d5 and the fourth resistor R d5 In series, the third RC branch, the fifth capacitor C d5 The capacitance of the fourth resistor R d5 The resistance matching configuration provides reverse voltage recovery time and suppresses commutation overvoltage when the second thyristor VT18 of the half-controlled valve VC5 is turned off.

2. The HVDC converter valve internal energy storage and consumption device according to claim 1, characterized in that: The full control valve VC3 includes: The collector of the second IGBTVT13 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 IGBTVT14, and the cathode of the diode D is connected to the emitter of the third IGBTVT14 and the third capacitor C d3 One end of the third capacitor C d3 The other end is connected to the emitter of the second IGBTVT13; When a fault occurs on the AC side and the surplus power exceeds the threshold, the third IGBTVT14 is turned on, and current flows through the third resistor R and the third capacitor C. d3 , the surplus power is dissipated through the third resistor R, while the third capacitor C d3 Absorb transient energy and store it in battery V B Charge; When a fault occurs on the AC side and the surplus power does not exceed the threshold, the third IGBTVT14 is turned off, and the current flows through the diode D and the third capacitor C. d3 The energy storage battery V B Charging, suppressing the rise of DC bus voltage; When a fault occurs on the DC side, the third IGBTVT14 is turned off and the energy storage battery V B The energy storage unit is discharged, and the current flows through the third capacitor C d3 The diode D supplements the missing power to the DC side to maintain the bus voltage stable.

3. The HVDC converter valve internal energy storage and consumption device according to claim 1, characterized in that: The full control valve VC4 includes: The collector of the fourth IGBTVT15 is connected to the fourth capacitor C d4 and the input end of the energy storage unit, and the emitter of the fourth IGBTVT15 is connected to the output end of the energy storage unit; When the energy storage battery V B When charging, the energy storage battery V B Through the inductor L to the fourth capacitor C d4 Charging, absorbing surplus power; When the energy storage battery V B When discharging, the fourth capacitor C d4 The energy storage battery V is supplied through the inductor L B Discharge to supplement the missing power; During normal operation, the fourth IGBTVT15 is turned on, and the energy storage unit is connected to the fourth capacitor C d4 Maintain voltage balance; When it is detected that the DC bus current exceeds a preset safety threshold or a short circuit fault occurs, the fourth IGBTVT15 is immediately turned off, cutting off the connection between the energy storage unit and the main circuit to avoid energy reverse impact.

4. The HVDC converter valve internal energy storage and consumption device according to claim 3, characterized in that: The energy storage unit comprises: The energy storage unit is composed of a bidirectional buck-boost circuit, which includes a fifth IGBTVT16, a sixth IGBTVT17, an inductor L and an energy storage battery V B ; The collector of the fifth IGBTVT16 is connected to the fourth capacitor C d4 , the emitter is connected to the collector of the sixth IGBTVT17 and one end of the inductor L; The emitter of the sixth IGBTVT17 is connected to the energy storage battery V B The negative electrode of the energy storage battery V B The positive electrode is connected to the other end of the inductor L; The fourth capacitor C d4 Connect the energy storage battery V B The negative electrode; When it is detected that the DC bus current exceeds the preset safety threshold or a short circuit fault occurs, the fourth IGBTVT15 is immediately turned off, and the fifth IGBTVT16 and the sixth IGBTVT17 are forced to turn off, so that the energy storage battery V B and the fourth capacitor C d4 Enter isolation.

5. The HVDC converter valve internal energy storage and consumption device according to claim 4, characterized in that: The bidirectional buck-boost circuit operates in the following modes: In charging mode, the fifth IGBTVT16 remains off, the sixth IGBTVT17 is turned on according to the PWM signal, and the current flows from the energy storage battery V B The positive electrode flows out, based on the inductance L, the energy storage battery V B The low voltage energy is converted into the fourth capacitor C d4 The high-voltage side energy is used for boost charging; In the discharge mode, the sixth IGBTVT17 is kept off, the fifth IGBTVT16 is turned on according to the PWM signal, and the current flows from the fourth capacitor C d4 outflow, based on the inductor L, the fourth capacitor C d4 The high voltage energy is converted into the energy storage battery V B The low-voltage side energy is discharged at a reduced voltage; In standby mode, the fifth IGBTVT16 and the sixth IGBTVT17 are both turned off, the fourth IGBTVT15 remains on, and the energy storage battery V B With the fourth capacitor C d4 The fourth IGBTVT15 is connected in parallel to the main circuit, so that the fourth capacitor C d4 The voltage at both ends is synchronized with the DC bus voltage.

6. The HVDC converter valve internal energy storage and consumption device according to claim 1, characterized in that: The fully controlled valve VC2 comprises: The collector of the first IGBTVT12 is connected to the input end of the commutation branch, the emitter is connected to the output end of the commutation branch, and the second resistance-capacitance branch is connected to the second capacitor C d2 and the second resistor R d2 are connected in series and in parallel to both ends of the first IGBTVT12; During normal operation or commutation, the first IGBTVT12 is turned on, and current flows through the commutation branch to complete commutation; When the commutation branch is turned off, the first IGBTVT12 is controlled to be turned off, and the second capacitor C d2 Absorb the transient voltage energy across the first IGBTVT12, the second resistor R d2 Limiting capacitor charge and discharge currents suppresses voltage spikes and reduces switching losses.

7. The HVDC converter valve internal energy storage and consumption device according to claim 1, characterized in that: The half-controlled valve VC1 and the half-controlled valve VC5 include: In the semi-controlled valve VC1, the first thyristor VT11 is subjected to reverse voltage during commutation, and the first RC branch provides reverse voltage recovery time for the first thyristor VT11. d1 Absorb commutation overvoltage; In the semi-controlled valve VC5, the second thyristor VT18 is subjected to reverse voltage after the energy storage and energy consumption branch is turned off. The third RC branch provides reverse voltage recovery time for the second thyristor VT18. At the same time, the fifth capacitor C d5 Suppress voltage spikes; During normal operation, the first thyristor VT11 and the second thyristor VT18 remain turned on, and 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 energy consumption branch.

8. A high-voltage direct current converter valve internal energy storage and consumption system, characterized in that: The system comprises: The system comprises a plurality of SM submodules, wherein the SM submodule comprises the commutation branch and the energy storage and consumption branch as claimed in claim 1; During normal commutation, the commutation branches of all the SM submodules receive a synchronous trigger signal to form a parallel current path; The commutation branches of each SM submodule ensure balanced voltage distribution through a voltage-sharing control strategy. When a bridge arm needs to be commutated, a commutation instruction is sent to the target SM submodule to shut down the commutation branch that needs to be commutated, and trigger the energy storage and consumption branch to transfer current to the energy storage and consumption branch of the target SM submodule; The commutation branches of the remaining non-commutated SM submodules remain conductive to maintain overall system current continuity; During normal operation, the commutation branches of each SM submodule evenly share the load current, and current sharing is achieved based on current closed-loop control. When a single SM submodule exits due to a fault, the remaining SM submodules increase the conduction ratio to compensate for the power gap of the faulty SM submodule; All the SM submodules are interconnected via a communication bus to exchange voltage, current and switch status information in real time.

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