Energy storage and energy consumption collaborative control system and method for flexible DC power grid side faults

Abstract

The present invention belongs to the field of power electronics technology, and discloses a coordinated control system and method for energy storage and energy consumption of flexible DC transmission network side faults. The system includes an energy storage module and an energy consumption module. The energy storage module and the energy consumption module are connected through an energy consumption path switching tube. The energy storage module is connected to the flexible DC transmission network bus, and is used for storing and consuming the surplus power of the flexible DC transmission network bus. By finely modulating N serially connected sub-modules, its flexible response ability under different working conditions is demonstrated. When the power system is in the transient stage, the sub-modules can quickly respond and convert the excess electric energy into chemical energy for storage, thereby effectively balancing the system power and preventing the power grid from overloading. When the system enters the steady-state operation, these sub-modules can release the stored energy according to the power grid demand, or ensure the stability and quality of power supply through fine adjustment of the power quality, meeting the user's demand for high-quality electric energy.

Description

Technical Field

[0001] The present invention belongs to the technical field of power electronics, and relates to a coordinated control system and method for energy storage and energy consumption of flexible DC transmission network side faults. Background Art

[0002] Offshore wind power has the advantages of not occupying land resources, being less affected by terrain factors, and having stable wind speeds, and has broad development prospects. However, the problem of reactive power loss exists when electric energy is sent out through AC submarine cables, which is not conducive to the development of wind power towards the deep sea. Flexible DC transmission technology is based on a voltage source converter (VSC), and has the advantages of independent regulation of active and reactive power, no commutation failure problem, and no need for reactive power compensation, and has been widely used in the transmission of far-sea wind power.

[0003] When the offshore wind power based on flexible DC transmission operates in a steady state, the active power of the sending-end wind farm and the receiving-end onshore power grid remains balanced. However, when a short-circuit fault occurs on the grid side, the grid-side voltage drops, and then the active power absorbed by the grid side will be reduced. Since the converter station of the offshore wind farm cannot sense the grid-side fault in time and the output power of the wind farm remains unchanged, it will lead to power imbalance between the sending end and the receiving end, and the surplus active power will cause the DC voltage to rise, and in severe cases, it will lead to system shutdown. In order to achieve the fault ride-through of the system during grid-side faults, it is necessary to reduce or absorb the surplus power that appears during grid-side faults. One method is to rely on communication lines to reduce the output power of the wind farm, but the communication system has the disadvantage of high delay, and the wind turbines have large inertia and it is difficult to respond to the requirements of fault ride-through in time; another method is to connect energy-consuming devices in parallel at both ends of the DC line, and convert the surplus power into heat energy through energy-consuming resistors and dissipate it, so as to maintain the voltage stability of the DC line. However, the consumed surplus power has the problem of energy waste, and the energy-consuming device needs to be equipped with a large heat dissipation device, which occupies a large area. Summary of the Invention

[0004] The purpose of the present invention is to provide a coordinated control system and method for energy storage and energy consumption of flexible DC transmission network side faults to solve the above problems.

[0005] To achieve the above purpose, the present invention adopts the following technical solutions:

[0006] In a first aspect, the present invention provides a coordinated control system for energy storage and energy consumption of flexible DC transmission network side faults, including an energy storage module and an energy consumption module. The energy storage module and the energy consumption module are connected through an energy consumption path switch tube. The energy storage module is connected to the flexible DC transmission network bus and is used for storing and consuming the surplus power of the flexible DC transmission network bus.

[0007] The energy storage module has a bipolar structure. Each pole includes a number of energy storage sub - modules and arm inductors. After a number of energy storage sub - modules are connected in series, they are connected in series with the arm inductor to the ground.

[0008] Furthermore, the energy - consuming module includes a resonant network, a diode rectifier bridge, a filter capacitor, and an energy - consuming resistor, which are connected in series.

[0009] Furthermore, the energy storage sub - module includes a half - bridge module, an inductor, and an energy storage battery. The half - bridge module is connected in parallel with the energy storage battery in series with the inductor.

[0010] Furthermore, the switching tubes of the half - bridge module and the energy - consuming path switching tubes are both insulated gate bipolar transistors with anti - parallel diodes.

[0011] Furthermore, the energy - consuming module is connected between the energy storage sub - module and the arm inductor through the energy - consuming path switching tube.

[0012] Furthermore, one end of the energy - consuming path switching tube is connected to the arm inductor Lp, and the other end is connected to the resonant network.

[0013] Furthermore, the resonant network is a series of inductor and capacitor.

[0014] In a second aspect, the present invention provides a control method for an energy storage and energy - consuming collaborative control system for a flexible DC transmission network - side fault, including the following steps:

[0015] By detecting the DC bus voltage in real - time to switch the control state, when the DC bus voltage is within the safe range, through N series - connected energy storage sub - modules, the energy fluctuation of the wind farm is supplemented and the power quality is regulated;

[0016] When the DC bus voltage exceeds the safe range, through N series - connected energy storage sub - modules, the surplus power is stored;

[0017] When the surplus power is greater than the absorption upper limit of the energy storage system, through N series - connected energy storage sub - modules, a resonant network, a filter capacitor, and an energy - consuming resistor, the surplus power is stored and consumed simultaneously.

[0018] Furthermore, the capacitor voltage of the energy storage sub - module controls the charge and discharge of the energy storage battery in parallel in the sub - module by controlling the number of sub - modules put into operation simultaneously.

[0019] Furthermore, during the steady state, the fluctuation amount of the wind farm output power is detected and absorbed or supplemented by using the energy storage state.

[0020] Furthermore, in the energy storage and energy - consuming state, N series - connected sub - modules are put into operation or cut off simultaneously. The series voltage of the sub - modules is equivalent to a two - level voltage, and the amplitude of the output voltage is adjusted by changing the frequency of the two - level voltage.

[0021] Compared with the prior art, the present invention has the following technical effects:

[0022] The present invention provides a system integrating energy storage and energy consumption functions, which can effectively manage the surplus power of the flexible DC transmission network bus. The bipolar structure design of the energy storage module improves the reliability and flexibility of the system and can cope with power flow in different directions. The design of the energy consumption module enables the safe consumption of surplus power when necessary, preventing grid overload or equipment damage.

[0023] The design of the energy storage sub-module enables each sub-module to independently control charge and discharge, improving the flexibility and response speed of the system. The combination of the half-bridge module and the inductor provides effective protection for the energy storage battery, preventing overcharging or over-discharging.

[0024] The use of an insulated gate bipolar transistor (IGBT) with an anti-parallel diode improves the efficiency and reliability of the switching tube. The anti-parallel diode provides reverse conduction ability, which helps to maintain the stability of the system when the power flow direction changes.

[0025] The flexible connection between the energy consumption module and the energy storage sub-module enables the system to quickly switch working modes according to actual needs. The control of the energy consumption path switching tube provides precise control over the input and output of the energy consumption module.

[0026] The position design of the energy consumption path switching tube enables the surplus power to be efficiently transmitted to the energy consumption module. The design of the resonant network helps to achieve smooth transition and consumption of power during the energy consumption process.

[0027] The series-connected inductor and capacitor constitute a simple and effective resonant network for absorbing and releasing energy during the energy consumption process. The design of the resonant network helps to reduce voltage and current fluctuations during the energy consumption process and improve the stability of the system.

[0028] The present invention also provides a real-time control strategy based on the DC bus voltage, enabling the system to automatically adjust the working mode according to the grid state. Under different working conditions, the system can flexibly respond to ensure the stable operation of the grid and power quality.

[0029] When the surplus power exceeds the absorption limit of the energy storage system, the system can simultaneously activate the energy storage and energy consumption functions to effectively prevent grid overload. The energy storage sub-module controls the charge and discharge of the parallel energy storage batteries in the sub-module by controlling the number of simultaneously input sub-modules; when in a steady state, it detects the fluctuation amount of the wind farm output power and absorbs or supplements it using the energy storage state. By controlling the number of simultaneously input sub-modules, the system can precisely adjust the charge and discharge state of the energy storage battery. In a steady state, the system can automatically adjust the energy storage state according to the fluctuation amount of the wind farm output power to maintain the stable operation of the grid. This control strategy improves the flexibility and response speed of the system and helps to cope with the challenges of wind farm energy fluctuations. Description of the Drawings

[0030] Figure 1 Schematic diagram of the integrated energy storage and energy consumption topology applied in the present invention;

[0031] Figure 2 Schematic diagram of the sub-module structure in the integrated energy storage and energy consumption topology applied in the present invention;

[0032] Figure 3 Schematic diagram of the energy storage state structure in the integrated energy storage and energy consumption topology applied in the present invention;

[0033] Figure 4 Block diagram of the energy storage state control strategy proposed by the present invention;

[0034] Figure 5 Block diagram of the energy storage and energy consumption state control strategy proposed by the present invention. Detailed Embodiment

[0035] Explanation of Related Terms:

[0036] IGBT: (Insulated Gate Bipolar Transistor) Insulated Gate Bipolar Transistor, which is a power semiconductor device;

[0037] PS-PWM: (Phase-Shift Pulse Width Modulation) Phase-Shift Pulse Width Modulation, which is a modulation method applied in power electronics and power conversion technologies;

[0038] PI: Proportional-Integral Controller, which is a linear controller widely applied in industrial control systems.

[0039] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the drawings:

[0040] Example 1, please refer to Figure 1 , the present invention provides a coordinated control system for energy storage and energy consumption of flexible DC transmission network side faults, including an energy storage module and an energy consumption module. The energy storage module and the energy consumption module are connected through an energy consumption path switch tube. The energy storage module is connected to the flexible DC transmission network bus for storing and consuming the surplus power of the flexible DC transmission network bus.

[0041] The integrated energy storage and energy consumption topology is a bipolar structure. Each pole is composed of N series-connected energy storage sub-modules, arm inductors, energy consumption path switch tubes, LC resonance networks, diode rectifier bridges, filter capacitors, and energy consumption resistors.

[0042] The submodule is composed of a half-bridge module and an energy storage battery with a series inductor connected in parallel.

[0043] The switch tubes in the submodule and the switch tubes in the energy consumption path are both insulated gate bipolar transistors IGBTs with anti-parallel diodes.

[0044] By connecting N series energy storage submodules, the surplus power can be stored and the power quality can be adjusted.

[0045] Through N series-connected energy storage submodules, resonant networks, filter capacitors, and energy-consuming resistors, the storage and consumption of surplus power are simultaneously achieved.

[0046] Embodiment 2, the present invention provides a coordinated energy storage and energy consumption control system for a fault on the flexible DC transmission network side, specifically comprising:

[0047] The energy storage module and the energy consumption module are connected through the energy consumption path switch tube, and the energy storage module is connected to the flexible DC transmission network busbar, mainly used to store and consume the surplus power of the flexible DC transmission network busbar. The energy storage module is designed as a bipolar structure, each pole contains several energy storage sub-modules connected in series and a bridge arm inductor L connected in series with it. p .

[0048] In the energy storage module, each energy storage submodule consists of a half-bridge module, an inductor, and an energy storage battery. These components are connected in parallel with the energy storage battery with the inductor in series. In particular, the switch tube of the half-bridge module and the energy consumption path switch tube both use IGBTs with anti-parallel diodes. This design improves the flexibility and reliability of the system.

[0049] The energy consumption module includes the resonant network LC, the diode rectifier bridge, and the filter capacitor C o And the energy dissipation resistor R o , these components are connected in series. The energy consumption module is connected to the energy storage submodule and the bridge arm inductor through the energy consumption path switch tube. The specific connection method is: one end of the energy consumption path switch tube is connected to the bridge arm inductor L p The other end is connected to the resonant network LC. The resonant network LC is composed of a series inductor L s and capacitor C b Composition, such a design helps to achieve efficient transfer and consumption of energy.

[0050] The energy storage and consumption integrated topology is a bipolar structure, each pole consists of N series sub-modules CELL1---CELL1N, bridge arm inductor L p , energy consumption path switch tube S r (S r '), LC resonant network, diode rectifier bridge, filter capacitor C o And the energy dissipation resistor Ro Composition.

[0051] Series sub - modules (CELL1 to CELLN) are connected in series to form a chain structure with voltage superposition. Each sub - module may contain energy - storage elements such as capacitors or batteries inside to provide a stable voltage output.

[0052] Arm inductor L p is connected to one end of the series sub - module chain and is connected to one end of the energy - consuming path switch tube S r (or S r '). The main function of inductor L p is to limit the rate of change of current, thereby smoothing the current waveform and reducing the impact of current fluctuations on the system.

[0053] Energy - consuming path switch tubes S r and S r ' are respectively connected to both sides of the arm inductor L p and are connected to the LC resonance network. These switch tubes are used to control the energy flow path and achieve energy transfer and dissipation through switching actions.

[0054] The LC resonance network is composed of inductor L and capacitor C and is connected between the energy - consuming path switch tube S r (S r ) and the diode rectifier bridge. This network utilizes the resonance characteristics of the inductor and capacitor to achieve power conversion and transmission at a specific frequency.

[0055] The diode rectifier bridge is composed of four diodes and is connected between the LC resonance network and the filter capacitor C o . The function of the rectifier bridge is to convert alternating current into direct current and provide a stable DC voltage for subsequent filtering and energy - consuming processes.

[0056] Filter capacitor C o is connected between the output terminal of the diode rectifier bridge and the energy - consuming resistor R o . The main function of the filter capacitor is to smooth the DC voltage waveform after rectification, reduce voltage fluctuations and ripples, and improve the stability of the output voltage v0.

[0057] Energy - consuming resistor R o is connected to the other end of the filter capacitor C o and is connected to other parts of the circuit. The main function of the energy - consuming resistor is to dissipate excess energy, prevent voltage back - rush and circuit over - voltage, and thus maintain the stable operation of the circuit.

[0058] Reference Figure 2, the integrated energy storage and consumption topology sub-module is composed of a half-bridge module in parallel with an energy storage battery with a series inductor Lb. When the upper switch S1 is closed and the lower switch S2 is open, the sub-module capacitor and the energy storage battery are in the input state. When the upper switch S1 is open and the lower switch S2 is closed, the sub-module capacitor and the energy storage battery are in the bypass state.

[0059] The half-bridge module includes two key switch tubes, namely the upper switch S1 and the lower switch S2. These two switch tubes are respectively connected to the upper and lower ends of the circuit to control the current flow direction.

[0060] When the upper switch S1 is closed and the lower switch S2 is open, the current can flow through S1 to the load. At this time, the sub-module capacitor and the energy storage battery are in the input state and jointly participate in the energy transmission and storage of the circuit.

[0061] When the upper switch S1 is open and the lower switch S2 is closed, the current then flows through S2 to the load. At this time, the sub-module capacitor and the energy storage battery are in the bypass state, the capacitor is isolated, and the energy storage battery works independently.

[0062] The inductor Lb is connected in series with the energy storage battery and plays a role in smoothing the current and storing energy in the circuit. One end of the inductor is connected to the output end of the half-bridge module, and the other end is connected to the load.

[0063] The capacitor C is connected in parallel with the output end of the half-bridge module and is used to store and release electrical energy to maintain the stability of the output voltage. Vcj is the voltage value of the capacitor C. In the input state, the capacitor C and the energy storage battery together participate in the energy transmission and storage of the circuit.

[0064] The energy storage battery is connected in series with the inductor Lb and in parallel with the capacitor C (through the control of the half-bridge module). In the input state, the energy storage battery and the capacitor C work together; in the bypass state, the energy storage battery works independently.

[0065] The switch tubes in the sub-module and the switch tubes of the energy consumption path are both IGBTs with anti-parallel diodes.

[0066] Reference Figure 3 , when the switch tube S of the energy consumption path r (S r ) is open, the energy consumption branch is cut off, and only N sub-modules are connected in series with the arm inductor Lp. This circuit state is called the energy storage state. When the switch tube S of the energy consumption path r (S r ) is closed, the energy consumption branch is connected to the energy storage state circuit. As shown in reference Figure 1 , this circuit state is called the energy storage and consumption state.

[0067] In the energy storage state, the capacitor voltage of the sub-module can be changed by modulating the switching quantity of the sub-module, and then the charging and discharging of the energy storage battery can be controlled; in the energy consumption state of the energy storage, N series-connected sub-modules are simultaneously put in or cut out, and the series voltage of the sub-modules is equivalent to a two-level voltage. Due to the existence of the LC resonance network, changing the frequency of the two-level voltage can change the amplitude of the output voltage, thereby changing the power consumption of the power consumption resistor. At the same time, the capacitor voltage of the sub-module can be changed by controlling the number of sub-modules put in simultaneously, so that the charging and discharging of the parallel energy storage battery in the sub-module can be controlled.

[0068] Reference Figure 4 :

[0069] Signal_1:

[0070] System status indication signal. Signal_1 = 0 indicates that the system is running normally; Signal_1 = 1 indicates that the system is in a fault state.

[0071] P wind and P wind_ref :

[0072] P _wind : The actual output power of the wind farm.

[0073] P _wind_ref : The rated power of the wind farm.

[0074] The difference between the two reflects the power fluctuation of the wind farm.

[0075] V dc and V dc_ref :

[0076] V dc : The actual DC bus voltage.

[0077] V dc_ref : The DC bus reference voltage, set to 1.05 p.u. (the unit is usually the voltage unit).

[0078] V dc The comparison between V dc_ref and V is used to judge whether the system is in a safe operating state.

[0079] P bat and P bat_ref :

[0080] P bat : The actual power of the energy storage system.

[0081] P bat_ref : The reference power of the energy storage system.

[0082] In the fault state, Pbat_ref Used to represent the surplus power that the energy storage system needs to absorb for the system.

[0083] I ref and I:

[0084] I ref : The reference current of the energy storage system.

[0085] I: The actual current of the energy storage system.

[0086] I ref Is calculated according to the system state and is used to control the current of the energy storage system.

[0087] PI controller:

[0088] Used to adjust the error and generate the reference wave of the sub-module.

[0089] PS-PWM:

[0090] Multi-phase shifted modulation pulse width modulation, used to generate the control signal of the sub-module switching tube.

[0091] Sub-module sorting and voltage equalization:

[0092] Sorting and voltage equalization of the sub-module capacitor voltage to ensure the stability of the sub-module voltage.

[0093] Sub-module switching signal:

[0094] The signal for controlling the sub-module switching tube, used to realize the switching of the sub-module.

[0095] Principle explanation

[0096] Normal operating state (Signal_1 = 0):

[0097] The system continuously detects the DC bus voltage V dc , if V dc , within the safe range (1.05 p.u.), the system operates stably.

[0098] At this time, the power absorbed by the grid side is equal to the power output by the wind farm, and the system maintains power balance.

[0099] By detecting the difference between the actual output power P wind of the wind farm and the rated power P wind_ref , the power fluctuation value of the wind farm is obtained.

[0100] Use the energy storage system to supplement or absorb this fluctuation value, maintain the constant power absorbed by the grid side, and improve the power quality of grid connection.

[0101] Divide the power fluctuation value of the wind farm by the DC bus voltage V dc, the current reference value I of the energy storage system is obtained ref .

[0102] I ref After taking the difference between I and the actual current I of the energy storage system and adjusting through a PI controller, a reference wave for the sub-module is generated.

[0103] After passing through PS-PWM modulation and equalizing the capacitor voltages of the sub-modules through sorting, signals for the sub-module switching tubes are generated to control the switching in and out of the sub-modules.

[0104] Fault state (Signal_1 = 1):

[0105] If the DC bus voltage V _dc exceeds the safe range (1.05 p.u.), it indicates that a grounding fault has occurred on the grid side and the system has surplus power.

[0106] At this time, the energy storage system needs to be used to absorb the surplus power.

[0107] Taking the difference between the actual DC bus voltage V dc and the reference voltage V dc_ref and calculating through a PI controller, the surplus power P of the system is obtained bat_ref .

[0108] Dividing the surplus power P bat_ref by the DC bus voltage V dc , the current reference value I_ of the energy storage system is obtained ref .

[0109] The subsequent process is the same as the normal operation state, that is, after taking the difference between I_ ref and the actual current I of the energy storage system and adjusting through a PI controller, a reference wave for the sub-module is generated, and after passing through PS-PWM modulation and equalizing the capacitor voltages of the sub-modules through sorting, signals for the sub-module switching tubes are generated.

[0110] By real-time monitoring parameters such as the DC bus voltage and the output power of the wind farm, calculating the current reference value of the energy storage system according to the system state, and then through steps such as a PI controller and PS-PWM modulation, signals for the sub-module switching tubes are finally generated, realizing the power balance and fault handling of the wind farm grid-connected system.

[0111] When the circuit is in the energy storage state, the DC bus voltage is detected in real time. If the DC bus voltage is within the safe range (1.05 p.u.), where p.u. represents per-unit value, it indicates that the system is operating stably. At this time, the power absorbed by the grid side is equal to the power output by the wind farm, and the system maintains power balance. Due to the volatility of wind power generation, the output power of the wind farm is unstable. Therefore, by detecting the actual output power of the wind farm and subtracting it from the rated power of the wind farm, the fluctuation value of the wind farm power can be obtained. Using the energy storage state to supplement or absorb this fluctuation value can maintain the constant power absorbed by the grid side and improve the quality of grid-connected electric energy. Therefore, dividing the wind farm power fluctuation value by the DC bus voltage gives the current reference value of the energy storage system. After subtracting it from the actual current of the energy storage system and passing it through a PI controller, a reference wave for the sub-module is generated. After multi-phase shifted modulation PS-PWM and capacitor voltage sorting and equalization of the sub-module, signals for the sub-module switching tubes are generated. If the DC bus voltage exceeds the safe range, it indicates that a ground fault has occurred on the grid side, and the system has surplus power, resulting in an increase in the DC bus voltage. At this time, the energy storage state needs to be used to absorb the surplus power. Subtracting the actual DC bus voltage from the reference voltage, calculating through a PI controller gives the surplus power of the system. Dividing the surplus power by the DC bus voltage gives the current reference value of the energy storage system. Then, after subtracting it from the actual current of the energy storage system and passing it through a PI controller, a reference wave for the sub-module is generated. After multi-phase shifted modulation PS-PWM and capacitor voltage sorting and equalization of the sub-module, signals for the sub-module switching tubes are generated.

[0112] Reference Figure 5 :

[0113] V dc : The actual DC bus voltage, representing the DC voltage value in the current system.

[0114] V dcref : The DC bus voltage reference value, which is the DC voltage value that the system expects to maintain.

[0115] P ref : The surplus power of the system, that is, the part where the actual power exceeds the system demand.

[0116] P bat_max : The maximum power that the energy storage system can absorb, representing the maximum surplus power that the energy storage device can handle.

[0117] P R_ref : The power that needs to be consumed by the dissipative resistor. When the surplus power exceeds the absorption capacity of the energy storage system, this part of the power will be consumed by the dissipative resistor.

[0118] V R_ref : The reference voltage across the dissipative resistor, which is a key parameter for controlling the power of the dissipative resistor.

[0119] VR : The actual voltage of the energy-consuming resistor represents the current operating voltage of the energy-consuming resistor.

[0120] f: The frequency of the two-level voltage, which is used to control the charging and discharging rate of the sub-module capacitor.

[0121] Sub-module capacitor reference voltage: It is an important parameter for controlling the sub-module switch tube signal and is used to maintain the stability of the sub-module capacitor voltage.

[0122] If the enabled energy storage state can absorb all the surplus power, the DC bus voltage can be stabilized within a safe range, and there is no need to start the energy-consuming device. When a serious fault occurs on the grid side and the surplus power is greater than the upper limit that the energy storage system can absorb, the surplus power that cannot be absorbed will cause the DC bus voltage to continue to rise. At this time, it is necessary to simultaneously turn on the energy-consuming branch to further absorb the excess surplus power. Refer to Figure 1 the topology. When the surplus power is greater than the upper limit that the energy storage system can absorb, close the energy-consuming path switch tube S r and S r ' to turn on the energy-consuming branch. As Figure 5 shown in (a) of Figure 5 : Take the difference between the actual DC bus voltage and the reference voltage, and calculate the surplus power of the system through a PI controller; as Figure 5 shown in (b) of

[0123] The above is only the preferred embodiment of the present invention and is not used to limit the technical solution of the present invention. Those skilled in the art should understand that without departing from the spirit and principle of the present invention, the technical solution can be modified and replaced simply in several aspects, and these modifications and replacements also fall within the protection scope covered by the claims.

Claims

1. A coordinated control system for energy storage and energy consumption of a flexible DC power grid side fault, characterized in that It includes an energy storage module and a power consumption module. The energy storage module and the power consumption module are connected by a power consumption path switching tube. The energy storage module is connected to the flexible DC transmission network bus for storing and consuming the surplus power of the flexible DC transmission network bus. The energy storage module has a bipolar structure. Each pole includes a number of energy storage sub-modules and a leg inductor. The number of energy storage sub-modules are connected in series and then connected in series with the leg inductor and grounded. The power consumption module includes a resonant network, a diode rectifier bridge, a filter capacitor, and a power consumption resistor. The resonant network, the diode rectifier bridge, the filter capacitor, and the power consumption resistor are connected in series in sequence. One end of the power consumption path switching tube is connected to the leg inductor, and the other end is connected to the resonant network.

2. The energy storage and energy consumption collaborative control system for flexible DC power grid side faults according to claim 1, wherein The energy storage sub-module includes a half-bridge module, an inductor, and an energy storage battery. The half-bridge module is connected in series with the inductor and then connected in parallel with the energy storage battery.

3. The energy storage and energy consumption collaborative control system for flexible DC power grid side faults according to claim 2, wherein The switching tube of the half-bridge module and the power consumption path switching tube are both insulated gate bipolar transistors with anti-parallel diodes.

4. The energy storage and energy consumption collaborative control system for flexible DC power grid side faults according to claim 1, characterized in that The power consumption module is connected between the energy storage sub-module and the leg inductor through the power consumption path switching tube.

5. The energy storage and energy consumption collaborative control system for flexible DC power grid side faults according to claim 1, characterized in that The resonant network is a series-connected inductor and capacitor.

6. A control method for an energy storage and power consumption collaborative control system for flexible DC transmission network side faults as described in any one of claims 1 to 5, comprising the following steps: By detecting the DC bus voltage in real time to switch the control state. When the DC bus voltage is within the safe range, the energy fluctuations of the wind farm are supplemented and the power quality is regulated through N series-connected energy storage sub-modules. When the DC bus voltage exceeds the safe range, the surplus power is stored through N series-connected energy storage sub-modules. When the surplus power is greater than the absorption upper limit of the energy storage system, the surplus power is stored and consumed simultaneously through N series-connected energy storage sub-modules, a resonant network, a filter capacitor, and a power consumption resistor. In the energy storage and power consumption state, N series-connected sub-modules are simultaneously put into or cut off. The series voltage of the sub-modules is equivalent to a two-level voltage, and the output voltage amplitude is regulated by changing the frequency of the two-level voltage.

7. The control method of the energy storage and energy consumption collaborative control system for flexible DC power grid side faults according to claim 6, characterized in that, The energy storage sub-module controls the charging and discharging of the parallel energy storage batteries in the sub-module by controlling the number of simultaneously put-in sub-modules.

8. The control method of the energy storage and energy consumption collaborative control system for flexible DC power grid side faults according to claim 7, characterized in that, During steady state, the fluctuation amount of the wind farm output power is detected and absorbed or supplemented using the energy storage state.

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