Dynamic performance test method and related device for energy self-balancing flexible straight valve energy release branch

Abstract

The present application discloses a method and related device for testing the dynamic performance of the energy self-balancing flexible straight valve energy discharge branch. The method includes: after the test valve is connected to the test system, the test parameters of the test valve are preset, and the test valve is operated in the maximum current continuous operating condition by adjusting the operating parameters; then the dynamic characteristics test of the energy discharge branch is started, and the voltage of the test valve submodule is raised by adjusting the amplitude of the modulation wave of the bridge arm where the accompanying test valve is located; the energy discharge branch is switched on and off according to the average voltage of the test valve submodule, and the phase angle and the amplitude of the modulation wave of the bridge arm where the accompanying test valve is located are adjusted at the same time; the above two steps are repeated according to the average energy absorption and maximum energy absorption of the energy discharge resistor of the submodule; finally, the test results are evaluated according to the voltage imbalance of the submodule and the energy absorption imbalance of the resistor. This solves the problem that the existing operating test system is prone to oscillation during the overall operation of the energy discharge branch, which causes the system protection to trip, ultimately leading to test failure.

Description

Technical Field

[0001] The present application relates to the technical field of flexible direct current transmission in power systems, and in particular to a dynamic performance test method and related device for an energy self-balancing flexible direct current valve energy discharge branch. Background Art

[0002] Flexible DC transmission converter valves, with their flexibility, controllability, and efficiency, hold broad application prospects in DC transmission and renewable energy grid integration. For island transmission applications, such as offshore wind power flexible DC transmission, conventional MMC topology-based flexible DC systems require the installation of AC or DC energy dissipation devices to limit overvoltages caused by excess power during faults at the receiving end, increasing construction costs. Currently, the submodules of self-balancing flexible DC valves feature active energy dissipation branches, eliminating energy dissipation devices and reducing submodule capacitance. This represents a new technology for addressing the problem of excess power at the receiving end of offshore wind power flexible DC systems during AC faults.

[0003] Energy self-balancing flexible straight valve topology Figure 2 As shown, the submodules in the bridge arm can adopt a full-bridge and half-bridge mixed cascade structure. The difference from the conventional MMC submodule is that a full-controlled power electronic switch and a resistor are connected in parallel at both ends of the capacitor of each submodule.

[0004] The energy-balancing flexible direct current valve's bridge arm submodule energy-drain branch utilizes a unified valve-controlled triggering strategy. When the bridge arm experiences an overall overvoltage, the submodule energy-drain branch's energy-drain resistors are uniformly activated to reduce the capacitor voltage and ensure submodule safety. Balancing the submodule voltages and energy absorbed by the energy-drain resistors during energy-drain branch operation is a key design consideration for the energy-balancing flexible direct current valve. Failure to balance the submodule voltages and energy absorbed by the energy-drain resistors within the bridge arm can lead to uneven voltages and excessive energy absorption between submodules, causing the submodule energy-drain branch to prematurely exit, ultimately leading to system fault ride-through failure and system lockout and tripping.

[0005] Currently, existing technologies lack research on dynamic performance testing of the energy-draining branch of a self-balancing flexible direct current valve, nor do they offer specialized testing methods for this dynamic performance. Existing flexible direct current valve testing systems also lack the ability to raise the overall bridge arm voltage, and their dynamic control stability is poor, making them prone to oscillation during the overall operation of the energy-draining branch, potentially causing system protection tripping and ultimately leading to test failure. Summary of the Invention

[0006] The present application provides a method and related device for testing the dynamic performance of the energy self-balancing flexible direct current valve energy discharge branch, which is used to solve the problem that the existing operation test system cannot raise the voltage of the energy self-balancing flexible direct current valve sub-module as a whole, and the energy discharge branch is triggered uniformly, which easily causes oscillation during the overall operation of the energy discharge branch and then the system protection trips, ultimately leading to test failure.

[0007] In view of this, the first aspect of the present application provides a method for testing the dynamic performance of an energy self-balancing flexible direct current valve energy discharge branch, wherein the energy discharge branch is composed of a fully controlled power electronic switch and an energy discharge resistor. The energy self-balancing flexible direct current valve to be tested is connected to a test system as a test valve. The submodule in the energy self-balancing flexible direct current valve has a built-in control device with a function of detecting operating parameters and a valve control with calculation and control functions. The test system includes: a DC voltage source, a bridge arm 1 consisting of a test valve and a source module, a bridge arm 2 where the test valve is located, and a connection reactance.

[0008] The method comprises:

[0009] S1. After the test valve is connected to the test system, the test parameters of the test valve are preset. The test parameters include: the input voltage U of the energy release branch; u , cut-off voltage U d , the maximum absorbed energy E of the energy dissipation resistor smu ;

[0010] S2. Setting the operating parameters of the bridge arm 1 and the bridge arm 2 so that the bridge arm 2 operates in a maximum current continuous operating condition;

[0011] S3, by adjusting the modulation wave amplitude of the bridge arm 1, so as to increase the voltage of the submodule where the test valve is located;

[0012] S4, switching the energy release branch on or off according to the average voltage of the submodule where the test valve is located, and adjusting the modulation wave phase angle and the modulation wave amplitude of the bridge arm 1, and then executing step S5;

[0013] S5, calculate the average absorbed energy of the energy dissipation resistor, when the average absorbed energy is less than the maximum absorbed energy E smu , return to step S3 until the average absorbed energy is not less than the maximum absorbed energy E smu , and calculate the voltage imbalance of the submodule where the test valve is located and the absorbed energy imbalance of the energy dissipation resistor;

[0014] S6. Analyze the dynamic performance of the energy release branch in the energy self-balancing flexible straight valve according to the voltage imbalance and the absorbed energy imbalance.

[0015] Optionally, step S2 includes:

[0016] By setting the modulation wave amplitudes of the bridge arm 1 and the bridge arm 2 to be n1, the voltage of the submodule where the test valve is located is not lower than the rated working voltage U sm1, and the modulation wave phase angle θ of the bridge arm 2 is set to θ1, so that the current of the bridge arm 2 is not lower than the maximum continuous operating current.

[0017] Optionally, step S3 includes:

[0018] In one power frequency cycle, the modulation wave amplitude of the bridge arm 1 is adjusted to n2, so that the voltage of the submodule where the test valve is located is increased;

[0019] in, ,satisfy ;

[0020] Where, and are the modulation wave amplitudes of the bridge arms, is the input voltage, is the rated operating voltage.

[0021] Optionally, step S4 includes:

[0022] The average voltage U of the submodule where the test valve is located is obtained by the valve control calculation avg；

[0023] When the average voltage U avg >The input voltage U u When , the valve control uniformly triggers the energy release branch of the test valve, and sets the modulation wave phase angle difference θ of the bridge arm 2 to 0, and reduces the modulation wave amplitude of the bridge arm 1 from n2 to n1;

[0024] When the average voltage U avg <The input voltage U u When , the valve control unit uniformly blocks the energy release branch of the test valve and sets the phase angle difference θ=θ1 of the bridge arm 2, so that the submodule where the test valve is located recovers to operate in the maximum current continuous operating condition.

[0025] Optionally, calculating the average absorbed energy of the energy dissipation resistor includes:

[0026] Calculating the average absorbed energy of the energy dissipation resistor based on the average absorbed energy calculation formula;

[0027] The calculation formula for the average absorbed energy is:

[0028] ;

[0029] Where, is the average absorbed energy of the energy dissipation resistor, is the energy absorbed by the corresponding submodule. is the number of test valve modules.

[0030] Optionally, the calculating the voltage imbalance of the submodule where the sample valve is located and the absorbed energy imbalance of the energy dissipation resistor includes:

[0031] The voltage imbalance of the submodule where the test valve is located is calculated based on the voltage imbalance calculation formula, and the absorbed energy imbalance of the energy dissipation resistor is calculated based on the energy dissipation resistor absorbed energy imbalance calculation formula;

[0032] The voltage imbalance calculation formula is:

[0033] ;

[0034] Where, is the voltage imbalance of the submodule where the test valve is located, The highest voltage of the test valve module, The lowest voltage of the test valve module. is the average voltage;

[0035] The calculation formula for the imbalance degree of energy absorbed by the energy dissipation resistor is:

[0036] ;

[0037] Where, is the energy absorption imbalance of the energy dissipation resistor, The maximum energy absorbed by the test valve module is is the minimum energy absorbed by the test valve module, is the average absorbed energy of the energy dissipation resistor.

[0038] Optionally, step S6 includes:

[0039] When the voltage imbalance is less than a preset percentage and the absorbed energy imbalance is less than a preset percentage, it is determined that the dynamic performance of the energy release branch in the test valve is qualified.

[0040] A second aspect of the present application provides a dynamic performance test device for the energy self-balancing flexible direct current valve energy discharge branch, wherein the energy discharge branch is composed of a fully controlled power electronic switch and an energy discharge resistor, and the energy self-balancing flexible direct current valve to be tested is connected to the test system as a test valve, and the submodule in the energy self-balancing flexible direct current valve has a built-in control device with a function of detecting operating parameters and a valve control with calculation and control functions, wherein the test system includes: a DC voltage source, a bridge arm 1 consisting of a test valve and a source module, a bridge arm 2 where the test valve is located, and a connection reactance;

[0041] The device comprises:

[0042] The first setting unit is used to preset the test parameters of the test valve after the test valve is connected to the test system. The test parameters include: the input voltage U u , cut-off voltage U d , the maximum absorbed energy E of the energy dissipation resistor smu ;

[0043] A second setting unit is used to set the operating parameters of the bridge arm 1 and the bridge arm 2 so that the bridge arm 2 operates in a maximum current continuous operating condition;

[0044] The first test unit is used to increase the voltage of the submodule where the test valve is located by adjusting the modulation wave amplitude of the bridge arm 1;

[0045] The second test unit is configured to switch the energy release branch on or off according to the average voltage of the submodule where the test valve is located, and to adjust the phase angle of the modulation wave and the amplitude of the modulation wave of the bridge arm 1 before executing step S5;

[0046] The third test unit is used to calculate the average absorbed energy of the energy dissipation resistor. When the average absorbed energy is less than the maximum absorbed energy E smu , trigger the first test unit until the average absorbed energy is not less than the maximum absorbed energy E smu , and calculate the voltage imbalance of the submodule where the test valve is located and the absorbed energy imbalance of the energy dissipation resistor;

[0047] The fourth test unit is used to analyze the dynamic performance of the energy release branch in the energy self-balancing flexible straight valve according to the voltage imbalance and the absorbed energy imbalance.

[0048] A third aspect of the present application provides a dynamic performance test device for an energy self-balancing flexible straight valve energy release branch, the device comprising a processor and a memory:

[0049] The memory is used to store program code and transmit the program code to the processor;

[0050] The processor is used to execute the steps of the dynamic performance test method of the energy self-balancing flexible straight valve energy release branch as described in the first aspect according to the instructions in the program code.

[0051] In a fourth aspect, the present application provides a computer-readable storage medium for storing program code, and the program code is used to execute the dynamic performance test method of the energy self-balancing flexible straight valve energy release branch described in the first aspect.

[0052] It can be seen from the above technical solutions that this application has the following advantages:

[0053] The present application provides a method for testing the dynamic performance of the energy self-balancing flexible direct current valve energy discharge branch. Based on the existing flexible direct current converter valve operation test system, it simulates the overall overvoltage condition of the bridge arm caused by a system failure during the normal operation of the energy self-balancing flexible direct current valve, uniformly triggers the action of the submodule energy discharge branch in the energy self-balancing flexible direct current valve, and verifies the voltage sharing, resistance energy balance, and energy tolerance between the submodules. This makes up for the problem of lack of effective testing means during the action of the energy self-balancing flexible direct current valve energy discharge branch, and solves the problem that the existing operation test system cannot raise the voltage of the energy self-balancing flexible direct current valve submodule as a whole, and the energy discharge branch is uniformly triggered, which is prone to oscillation during the overall action of the energy discharge branch and then the system protection trips, which ultimately leads to test failure. The present application can be carried out using the existing mature flexible direct current converter valve operation test system, without the need to build a new test system, and has the advantages of low investment and simple test methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A flow chart of a method for testing the dynamic performance of an energy self-balancing flexible straight valve energy release branch provided in an embodiment of the present application;

[0055] Figure 2 This is a topological diagram of the energy self-balancing flexible straight valve provided in an embodiment of the present application;

[0056] Figure 3 The topology of the dynamic performance test system of the energy self-balancing flexible straight valve energy release branch provided in the embodiment of the present application;

[0057] Figure 4 This is a diagram showing the effect of the test method provided in the examples of this application;

[0058] Figure 5 This is a diagram showing the effect of the submodule voltage and resistance energy absorption imbalance provided in the embodiment of the present application;

[0059] Figure 6 This is a structural schematic diagram of a dynamic performance test device for an energy self-balancing flexible straight valve energy release branch provided in an embodiment of the present application. DETAILED DESCRIPTION

[0060] In order to help those skilled in the art better understand the present invention, the following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of this application.

[0061] See also Figure 1, a dynamic performance test method for the energy self-balancing flexible direct current valve energy discharge branch provided in the embodiment of the present application, the energy discharge branch is composed of a fully controlled power electronic switch and an energy discharge resistor, the energy self-balancing flexible direct current valve to be tested is connected to the test system as a test valve, the submodule in the energy self-balancing flexible direct current valve has a built-in control device with a function of detecting operating parameters and a valve control with a calculation and control function, wherein the test system includes: a DC voltage source, a test valve and a source module composed of a square, which actively puts the bridge arm submodule into the energy discharge branch when the whole is over-voltage, thereby discharging energy, reducing the capacitor voltage, and ensuring the safety of the converter valve equipment.

[0062] It should be noted that, in one embodiment, the energy self-balancing flexible straight valve energy release branch dynamic performance test system of the present application is as follows: Figure 3 As shown in FIG, the test system mainly includes: a DC voltage source, a bridge arm 1 composed of a test valve and a source module, a bridge arm 2 where the test valve is located, and a connection reactance.

[0063] Methods include:

[0064] Step 101: After the test valve is connected to the test system, the test parameters of the test valve are preset. The test parameters include: the input voltage U of the energy release branch; u , cut-off voltage U d , the maximum absorbed energy E of the energy dissipation resistor smu .

[0065] It should be noted that before starting the dynamic performance test of the energy self-balancing flexible straight valve energy release branch, that is, before the energy self-balancing flexible straight valve assembly is connected to the test system as a test valve, it is necessary to preset the test parameters of the test valve. The test parameters include: the input voltage U of the energy release branch u , cut-off voltage U d , the maximum absorbed energy E of the energy dissipation resistor smu , where the input voltage U of the energy dissipation branch is u , cut-off voltage U d , the maximum absorbed energy E of the energy dissipation resistor smu The set value is determined based on the design parameters of the flexible straight line project to which the test valve belongs.

[0066] Step 102 : Setting the operating parameters of bridge arm 1 and bridge arm 2 so that bridge arm 2 operates in a maximum current continuous operating condition.

[0067] In one embodiment, step 102 includes:

[0068] By setting the modulation wave amplitude of bridge arm 1 and bridge arm 2 to be n1, the voltage of the submodule where the test valve is located is not lower than the rated working voltage U sm1 , and the modulation wave phase angle θ of bridge arm 2 is set to θ1, so that the current of bridge arm 2 is not lower than the maximum continuous operating current.

[0069] It should be noted that in order to make the submodule where the test valve is located operate under the maximum current continuous operation condition, specifically, the modulation wave amplitudes of the bridge arms where the test valve and the test valve are located, that is, the modulation wave amplitudes of bridge arm 1 and bridge arm 2 are both given as n1 (n1 is a positive integer), and the voltage of the submodule where the test valve is located is not lower than the rated working voltage U sm1 , assume that the modulation wave phase angle θ=θ1 of the bridge arm where the test valve is located, so that the current of the bridge arm 2 where the test valve is located is not lower than the maximum continuous operating current.

[0070] Step 103 : Adjust the modulation wave amplitude of the bridge arm 1 to increase the voltage of the submodule where the test valve is located.

[0071] In one embodiment, step 103 includes:

[0072] In one power frequency cycle, adjust the modulation wave amplitude of bridge arm 1 to n2, so that the voltage of the submodule where the test valve is located is increased;

[0073] in, ,satisfy ;

[0074] Where, and are the modulation wave amplitudes of the bridge arms, is the input voltage, is the rated operating voltage.

[0075] It is understandable that step 103 starts the dynamic performance test of the energy release branch. First, step 103 adjusts the modulation wave amplitude of the bridge arm 1 where the accompanying test valve is located, thereby raising the voltage of the submodule of the test valve.

[0076] Step 104 , switching the energy dissipation branch on or off according to the average voltage of the submodule where the test valve is located, and adjusting the modulation wave phase angle and the modulation wave amplitude of the bridge arm 1 , and then executing step 105 .

[0077] In one embodiment, step 104 includes:

[0078] The average voltage U of the submodule where the test valve is located is obtained through valve control calculation avg；

[0079] When the average voltage U avg >Input voltage U u When , the valve control triggers the energy release branch of the test valve uniformly, and sets the modulation wave phase angle difference θ of bridge arm 2 to 0, and reduces the modulation wave amplitude of bridge arm 1 from n2 to n1;

[0080] When the average voltage U avg <Input voltage U uWhen , the valve control unit uniformly blocks the energy release branch of the test valve and sets the phase angle difference θ=θ1 of the bridge arm 2, so that the submodule where the test valve is located recovers to operate under the maximum current continuous operating condition.

[0081] It should be noted that the energy self-balancing flexible direct current valve sub-module has a built-in control device, which monitors the working status of the sub-module, the capacitor voltage, and the energy absorbed by the energy dissipation resistor in real time, and uploads it to the valve control, and switches the sub-module and the energy dissipation resistor on and off according to the instructions of the valve control.

[0082] Step 105: Calculate the average absorbed energy of the energy dissipation resistor. When the average absorbed energy is less than the maximum absorbed energy E smu , return to step 103 until the average absorbed energy is not less than the maximum absorbed energy E smu , and calculate the voltage imbalance of the submodule where the test valve is located and the absorbed energy imbalance of the energy dissipation resistor.

[0083] In one embodiment, calculating the average absorbed energy of the energy dissipation resistor in step 105 includes:

[0084] Calculate the average absorbed energy of the energy dissipation resistor based on the average absorbed energy calculation formula;

[0085] The calculation formula for the average absorbed energy is:

[0086] ;

[0087] Where, is the average absorbed energy of the energy dissipation resistor, is the energy absorbed by the corresponding submodule. is the number of test valve modules.

[0088] It should be noted that the calculations in this application are all performed through valve control.

[0089] In one embodiment, calculating the voltage imbalance of the submodule where the test valve is located and the energy absorption imbalance of the energy dissipation resistor in step 105 includes:

[0090] The voltage imbalance of the submodule where the test valve is located is calculated based on the voltage imbalance calculation formula, and the absorbed energy imbalance of the energy dissipation resistor is calculated based on the energy dissipation resistor calculation formula;

[0091] The calculation formula for voltage imbalance is:

[0092] ;

[0093] Where, is the voltage imbalance of the submodule where the test valve is located, The highest voltage of the test valve module, The lowest voltage of the test valve module. is the average voltage;

[0094] The calculation formula for energy dissipation resistance is:

[0095] ;

[0096] Where, is the imbalance of energy absorption of the energy dissipation resistor, The maximum energy absorbed by the test valve module is is the minimum energy absorbed by the test valve module, is the average absorbed energy of the energy dissipation resistor.

[0097] Step 106: Analyze the dynamic performance of the energy release branch in the energy self-balancing flexible straight valve according to the voltage imbalance and the absorbed energy imbalance.

[0098] In one embodiment, step 106 includes:

[0099] When the voltage imbalance is less than a preset percentage and the absorbed energy imbalance is less than a preset percentage, the dynamic performance of the energy release branch in the test valve is determined to be qualified.

[0100] It should be noted that, specifically, for example, if the voltage imbalance of the test valve sub-module is detected to be less than 10% during the operation of the energy release branch, and the energy absorption imbalance of the energy release resistor of the test valve sub-module is detected to be less than 10% after the test, then the dynamic performance of the test valve energy release branch is judged to be qualified; otherwise, it is unqualified.

[0101] The following is an explanation of the test results obtained according to the test method of this application:

[0102] like Figure 4As shown, the first window at the top shows the voltage of the test valve bridge arm (red) and the voltage of the companion valve bridge arm (black). The energy-drain branch dynamic performance test begins at 3 seconds. Before 3 seconds, both bridge arms output a voltage level of 4 (modulation amplitude of 4). After the energy-drain branch dynamic performance test begins at 3 seconds, the modulation amplitude of the companion valve bridge arm is adjusted to 6 within 20ms, reaching a maximum output of 6 voltage levels to charge the test valve submodule. The upper right corner of the first window shows the expanded waveform at 3 seconds, illustrating the evolution of the voltage level. The second window shows the bridge arm current. Before 3 seconds and after 3.6 seconds, the bridge arm operates at maximum current continuous operation. Between 3 and 3.6 seconds, the phase angle is adjusted due to the activation of the energy-drain branch, resulting in a decrease in bridge arm current. The third window shows the capacitor voltage of the test valve submodule. It can be seen that it begins to rise at 3 seconds, reaching a maximum of 3050V when the energy-drain branch activates. The fourth window shows the energy-drain branch conduction command. The system remains in operation during the test. This effect diagram only shows the electrical quantity change process of one energy dissipation branch action. Multiple tests can be carried out based on the relationship between the average absorbed energy and the maximum absorbed energy of the sub-module energy dissipation resistor.

[0103] like Figure 5 As shown in the graph showing the effect of submodule voltage and energy absorption imbalance of the energy dump resistor obtained according to the test method provided in this application, the submodule voltage imbalance during the energy dump branch operation was less than 3.5%, and the energy absorption imbalance of the submodule energy dump resistor of the test valve after the test was completed was less than 7.0%, indicating that the dynamic performance of the energy dump branch of the test valve was qualified. According to the test method provided by the present invention, the entire test process verified the dynamic performance of the energy dump branch of the energy self-balancing flexible straight valve.

[0104] In summary, the present application proposes a method for testing the dynamic performance of the energy self-balancing flexible direct current valve energy discharge branch. This method is based on the existing flexible direct current converter valve operation test system. It simulates the overall overvoltage condition of the bridge arm caused by a system failure during the normal operation of the energy self-balancing flexible direct current valve, uniformly triggers the action of the submodule energy discharge branch in the energy self-balancing flexible direct current valve, and verifies the voltage sharing, resistance energy balance, and energy tolerance between the submodules. This method makes up for the lack of effective testing means during the action of the energy self-balancing flexible direct current valve energy discharge branch, and solves the problem that the existing operation test system cannot raise the voltage of the energy self-balancing flexible direct current valve submodule as a whole, and the energy discharge branch is uniformly triggered, which easily causes oscillation during the overall action of the energy discharge branch and then the system protection trips, ultimately leading to test failure. The present application can be carried out using the existing mature flexible direct current converter valve operation test system without the need to build a new test system. It has the advantages of low investment and simple test methods.

[0105] The above is a dynamic performance test method for the energy self-balancing flexible straight valve energy release branch provided in an embodiment of the present application. The following is a dynamic performance test device for the energy self-balancing flexible straight valve energy release branch provided in an embodiment of the present application.

[0106] See also Figure 2 In one embodiment of the present application, a dynamic performance test device for the energy-discharging branch of an energy-balancing flexible direct current valve is provided. The energy-discharging branch is composed of a fully controlled power electronic switch and an energy-discharging resistor. The energy-balancing flexible direct current valve to be tested is connected to the test system as a test valve. The submodule of the energy-balancing flexible direct current valve has a built-in control device with a function of detecting operating parameters and a valve control with calculation and control functions. The test system includes: a DC voltage source, a bridge arm 1 consisting of a test valve and a source module, a bridge arm 2 where the test valve is located, and a connection reactance.

[0107] The device includes:

[0108] The first setting unit 201 is used to preset the test parameters of the test valve after the test valve is connected to the test system. The test parameters include: the input voltage U u , cut-off voltage U d , the maximum absorbed energy E of the energy dissipation resistor smu .

[0109] The second setting unit 202 is used to set the operating parameters of the bridge arm 1 and the bridge arm 2 so that the bridge arm 2 operates in the maximum current continuous operating condition.

[0110] The first test unit 203 is used to increase the voltage of the submodule where the test valve is located by adjusting the modulation wave amplitude of the bridge arm 1.

[0111] The second test unit 204 is used to switch the energy release branch on or off according to the average voltage of the submodule where the test valve is located, and to adjust the modulation wave phase angle and the modulation wave amplitude of the bridge arm 1 before executing step S5.

[0112] The third test unit 205 is used to calculate the average absorbed energy of the energy dissipation resistor. When the average absorbed energy is less than the maximum absorbed energy E smu , trigger the first test unit 203 until the average absorbed energy is not less than the maximum absorbed energy E smu , and calculate the voltage imbalance of the submodule where the test valve is located and the absorbed energy imbalance of the energy dissipation resistor.

[0113] The fourth test unit 206 is used to analyze the dynamic performance of the energy release branch in the energy self-balancing flexible straight valve according to the voltage imbalance and the absorbed energy imbalance.

[0114] Furthermore, an embodiment of the present application also provides a dynamic performance test device for an energy self-balancing flexible straight valve energy release branch, the device comprising a processor and a memory:

[0115] The memory is used to store program code and transmit the program code to the processor;

[0116] The processor is used to execute the steps of the dynamic performance test method of the energy self-balancing flexible straight valve energy release branch as described in the above method embodiment according to the instructions in the program code.

[0117] Furthermore, an embodiment of the present application also provides a computer-readable storage medium, which is used to store program code, and the program code is used to execute the method described in the above method embodiment.

[0118] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the above-described systems and units can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0119] The terms "first," "second," "third," "fourth," and the like (if any) in the specification of the present application and the accompanying drawings are used to distinguish similar objects and are not necessarily used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate, so that the embodiments of the present application described herein can, for example, be implemented in an order other than those illustrated or described herein. In addition, the terms "including" and "having," and any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, product, or apparatus comprising a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units that are not explicitly listed or that are inherent to such process, method, product, or apparatus.

[0120] It should be understood that in this application, "at least one (item)" means one or more, and "plurality" means two or more. "And / or" is used to describe the association relationship of associated objects, indicating that three relationships can exist. For example, "A and / or B" can mean: only A exists, only B exists, and A and B exist at the same time, where A and B can be singular or plural. The character " / " generally indicates that the previous and next associated objects are in an "or" relationship. "At least one of the following items" or similar expressions refers to any combination of these items, including any combination of single or plural items. For example, at least one of a, b or c can mean: a, b, c, "a and b", "a and c", "b and c", or "a and b and c", where a, b, c can be single or plural.

[0121] In the several embodiments provided in this application, it should be understood that the disclosed systems, devices and methods can be implemented in other ways. For example, the device embodiments described above are merely schematic. For example, the division of the units is merely a logical function division. In actual implementation, there may be other division methods, such as multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the mutual coupling or direct coupling or communication connection shown or discussed can be an indirect coupling or communication connection through some interfaces, devices or units, which can be electrical, mechanical or other forms.

[0122] The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed across multiple network units. Some or all of these units may be selected to achieve the purpose of this embodiment according to actual needs.

[0123] In addition, the functional units in the various embodiments of the present application may be integrated into a single processing unit, or each unit may exist physically separately, or two or more units may be integrated into a single unit. The aforementioned integrated units may be implemented in the form of hardware or software functional units.

[0124] If the integrated unit is implemented in the form of a software functional unit and sold or used as an independent product, it can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present application, or the part that contributes to the prior art, or all or part of the technical solution can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for enabling a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present application. The aforementioned storage medium includes: U disk, mobile hard disk, read-only memory (full name: Read-Only Memory, English abbreviation: ROM), random access memory (full name: Random Access Memory, English abbreviation: RAM), disk or optical disk, and other media that can store program code.

[0125] As described above, the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for testing the dynamic performance of an energy self-balancing flexible straight valve energy release branch, characterized in that: The energy dissipation branch is composed of a fully controlled power electronic switch and an energy dissipation resistor. The energy self-balancing flexible direct current valve to be tested is connected to the test system as a test valve. The submodule of the energy self-balancing flexible direct current valve has a built-in control device with a function of detecting operating parameters and a valve control with calculation and control functions. The test system includes: a DC voltage source, a bridge arm 1 consisting of a test valve and a source module, a bridge arm 2 where the test valve is located, and a connection reactance. Methods include: S1. After the test valve is connected to the test system, the test parameters of the test valve are preset. The test parameters include: the input voltage U of the energy release branch; u , cut-off voltage U d , the maximum absorbed energy E of the energy dissipation resistor smu ; S2. Setting the operating parameters of the bridge arm 1 and the bridge arm 2 so that the bridge arm 2 operates in a maximum current continuous operating condition; S3, by adjusting the modulation wave amplitude of the bridge arm 1, so as to increase the voltage of the submodule where the test valve is located; S4, switching the energy release branch on or off according to the average voltage of the submodule where the test valve is located, and adjusting the modulation wave phase angle and the modulation wave amplitude of the bridge arm 1, and then executing step S5; S5, calculate the average absorbed energy of the energy dissipation resistor, when the average absorbed energy is less than the maximum absorbed energy E smu , return to step S3 until the average absorbed energy is not less than the maximum absorbed energy E smu , and calculate the voltage imbalance of the submodule where the test valve is located and the absorbed energy imbalance of the energy dissipation resistor; S6. Analyze the dynamic performance of the energy release branch in the energy self-balancing flexible straight valve according to the voltage imbalance and the absorbed energy imbalance.

2. The dynamic performance test method of the energy self-balancing flexible straight valve energy release branch according to claim 1 is characterized in that: Step S2 includes: By setting the modulation wave amplitudes of the bridge arm 1 and the bridge arm 2 to be n1, the voltage of the submodule where the test valve is located is not lower than the rated working voltage U sm1 , and the modulation wave phase angle θ of the bridge arm 2 is set to θ1, so that the current of the bridge arm 2 is not lower than the maximum continuous operating current.

3. The dynamic performance test method of the energy self-balancing flexible straight valve energy release branch according to claim 2 is characterized in that: Step S3 includes: In one power frequency cycle, the modulation wave amplitude of the bridge arm 1 is adjusted to n2, so that the voltage of the submodule where the test valve is located is increased; in, ,satisfy ; Where, and are the modulation wave amplitudes of the bridge arms, is the input voltage, is the rated operating voltage.

4. The dynamic performance test method of the energy self-balancing flexible straight valve energy release branch according to claim 2 is characterized in that: Step S4 includes: The average voltage U of the submodule where the test valve is located is obtained by the valve control calculation avg； When the average voltage U avg >The input voltage U u When , the valve control uniformly triggers the energy release branch of the test valve, and sets the modulation wave phase angle difference θ of the bridge arm 2 to 0, and reduces the modulation wave amplitude of the bridge arm 1 from n2 to n1; When the average voltage U avg <The input voltage U u When , the valve control unit uniformly blocks the energy release branch of the test valve and sets the phase angle difference θ=θ1 of the bridge arm 2, so that the submodule where the test valve is located recovers to operate in the maximum current continuous operating condition.

5. The dynamic performance test method of the energy self-balancing flexible straight valve energy release branch according to claim 2 is characterized in that: The calculating the average absorbed energy of the energy dissipation resistor includes: Calculating the average absorbed energy of the energy dissipation resistor based on the average absorbed energy calculation formula; The calculation formula for the average absorbed energy is: ； Where, is the average absorbed energy of the energy dissipation resistor, is the energy absorbed by the corresponding submodule. is the number of test valve modules.

6. The dynamic performance test method of the energy self-balancing flexible straight valve energy release branch according to claim 2 is characterized in that: The calculating of the voltage imbalance of the submodule where the test valve is located and the absorption energy imbalance of the energy dissipation resistor includes: The voltage imbalance of the submodule where the test valve is located is calculated based on the voltage imbalance calculation formula, and the absorbed energy imbalance of the energy dissipation resistor is calculated based on the energy dissipation resistor absorbed energy imbalance calculation formula; The voltage imbalance calculation formula is: ； Where, is the voltage imbalance of the submodule where the test valve is located, The highest voltage of the test valve module, The lowest voltage of the test valve module. is the average voltage; The calculation formula for the imbalance degree of energy absorbed by the energy dissipation resistor is: ； Where, is the energy absorption imbalance of the energy dissipation resistor, The maximum energy absorbed by the test valve module is is the minimum energy absorbed by the test valve module, is the average absorbed energy of the energy dissipation resistor.

7. The method for testing the dynamic performance of the energy self-balancing flexible straight valve energy release branch according to claim 1 is characterized in that: Step S6 includes: When the voltage imbalance is less than a preset percentage and the absorbed energy imbalance is less than a preset percentage, it is determined that the dynamic performance of the energy release branch in the test valve is qualified.

8. An energy self-balancing flexible straight valve energy release branch dynamic performance test device, characterized in that: The energy dissipation branch is composed of a fully controlled power electronic switch and an energy dissipation resistor. The energy self-balancing flexible direct current valve to be tested is connected to the test system as a test valve. The submodule of the energy self-balancing flexible direct current valve has a built-in control device with a function of detecting operating parameters and a valve control with calculation and control functions. The test system includes: a DC voltage source, a bridge arm 1 consisting of a test valve and a source module, a bridge arm 2 where the test valve is located, and a connection reactance. The device includes: The first setting unit is used to preset the test parameters of the test valve after the test valve is connected to the test system. The test parameters include: the input voltage U u , cut-off voltage U d , the maximum absorbed energy E of the energy dissipation resistor smu ; A second setting unit is used to set the operating parameters of the bridge arm 1 and the bridge arm 2 so that the bridge arm 2 operates in a maximum current continuous operating condition; The first test unit is used to increase the voltage of the submodule where the test valve is located by adjusting the modulation wave amplitude of the bridge arm 1; The second test unit is configured to switch the energy release branch on or off according to the average voltage of the submodule where the test valve is located, and to adjust the phase angle of the modulation wave and the amplitude of the modulation wave of the bridge arm 1 before executing step S5; The third test unit is used to calculate the average absorbed energy of the energy dissipation resistor. When the average absorbed energy is less than the maximum absorbed energy E smu , trigger the first test unit until the average absorbed energy is not less than the maximum absorbed energy E smu , and calculate the voltage imbalance of the submodule where the test valve is located and the absorbed energy imbalance of the energy dissipation resistor; The fourth test unit is used to analyze the dynamic performance of the energy release branch in the energy self-balancing flexible straight valve according to the voltage imbalance and the absorbed energy imbalance.

9. An energy self-balancing flexible straight valve energy release branch dynamic performance test equipment, characterized in that: The device includes a processor and a memory: The memory is used to store program code and transmit the program code to the processor; The processor is used to execute the dynamic performance test method of the energy self-balancing flexible straight valve energy release branch according to any one of claims 1 to 7 according to the instructions in the program code.

10. A computer-readable storage medium, characterized in that The computer-readable storage medium is used to store program code, and the program code is used to execute the dynamic performance test method of the energy self-balancing flexible straight valve energy release branch according to any one of claims 1 to 7.

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