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

Abstract

The invention discloses an energy self-balancing flexible straight valve energy release branch dynamic performance test method and related device, and the method comprises the steps: presetting test parameters of a test sample valve after the test sample valve is connected to a test system, and enabling the test sample valve to operate in a maximum current continuous operation condition through adjusting the operation parameters; starting an energy release branch dynamic characteristic test, and increasing the voltage of a test object valve sub-module by adjusting the modulation wave amplitude of a bridge arm where an accompanying test valve is located; switching on and switching off an energy release branch according to the average voltage of the sample valve sub-module, and simultaneously adjusting a phase angle and a modulation wave amplitude value of a bridge arm where an accompanying test valve is located; repeating the two steps according to the average absorption energy and the maximum absorption energy of the energy release resistors of the sub-modules; and finally, judging a test result according to the sub-module voltage unbalance degree and the resistance absorption energy unbalance degree. Therefore, the problem that the existing operation test system is easy to oscillate during the whole action period of the energy release branch, so that the system protection trips, and finally the test fails is solved.

Description

Technical Field

[0001] The present application relates to the technical field of flexible direct current transmission of electric 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 have broad application prospects in DC transmission, renewable energy generation and grid connection due to their flexibility, controllability and high efficiency. For offshore wind power flexible DC transmission and other island transmission application scenarios, in order to limit the overvoltage caused by surplus power when the receiving end fails, the flexible DC system based on conventional MMC topology needs to be equipped with AC or DC energy-consuming devices, which increases the cost of engineering construction. At present, the submodule of the energy self-balancing flexible DC valve has an active energy discharge branch, which can save energy-consuming devices and reduce the capacitance of the submodule. It is a new technology to solve the problem of surplus power at the receiving end of offshore wind power flexible DC system.

[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 submodules is that a fully controlled power electronic switch and a resistor are connected in parallel at both ends of the capacitor of each submodule to form an energy dissipation branch.

[0004] The energy discharge branch of the bridge arm submodule of the energy self-balancing flexible direct current valve adopts a valve-controlled unified triggering strategy. When the bridge arm is over-voltage as a whole, the energy discharge resistor of the submodule energy discharge branch is uniformly controlled to be put into operation to reduce the capacitor voltage and ensure the safety of the submodule. The balancing effect of the submodule voltage and the energy absorbed by the energy discharge resistor during the action of the energy discharge branch is the focus of the design assessment of the energy discharge branch of the energy self-balancing flexible direct current valve. If the submodule voltage in the bridge arm and the energy absorbed by the energy discharge resistor cannot be balanced, there will be uneven pressure and excessive absorption energy between the submodules, causing the submodule energy discharge branch to exit prematurely, which may eventually lead to the failure of system fault crossing and the problem of system lockout tripping.

[0005] At present, the existing technology has not conducted research on the dynamic performance test of the energy self-balancing flexible direct current valve during the operation of the energy discharge branch, and there is no special test method for the dynamic performance of the energy self-balancing flexible direct current valve. The existing flexible direct current valve test system does not have the function of raising the voltage of the bridge arm as a whole, and the dynamic control stability is poor. It is easy to oscillate during the overall operation of the energy discharge branch, and then the system protection trips, which ultimately leads 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 is prone to oscillation during the overall action of the energy discharge branch, thereby causing the system protection to trip, and 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, 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 is built-in with a control device having a function of detecting operating parameters and a valve control having a calculation and control function, wherein the test system comprises: a bridge arm 1 composed of a DC voltage source, 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 u , cut-off voltage U d , the maximum absorbed energy E of the energy dissipation resistor smu ;

[0010] S2, by setting the operating parameters of the bridge arm 1 and the bridge arm 2, 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, the voltage of the submodule where the test valve is located is raised;

[0012] S4, according to the average voltage of the submodule where the test valve is located, the energy dissipation branch is switched on or off, and the modulation wave phase angle and the modulation wave amplitude of the bridge arm 1 are adjusted at the same time, and then step S5 is executed;

[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 assuming that the modulation wave amplitudes of the bridge arm 1 and the bridge arm 2 are both 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] In the formula, 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 decreases 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 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] Based on the average absorbed energy calculation formula, the average absorbed energy of the energy dissipation resistor is calculated;

[0027] Wherein, the average absorbed energy calculation formula is:

[0028] ;

[0029] In the formula, 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 test 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 absorption imbalance calculation formula of the energy dissipation resistor;

[0032] The voltage imbalance calculation formula is:

[0033] ;

[0034] In the formula, is the voltage imbalance of the submodule where the test valve is located, is the highest voltage of the test valve module, is the minimum 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] In the formula, is the unbalanced degree of energy absorption of the energy dissipation resistor, The maximum energy absorbed by the test valve module. 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] The 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 is built-in with a control device having a function of detecting operating parameters and a valve control having a calculation and control function, wherein the test system comprises: a bridge arm 1 composed of a DC voltage source, 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 raise 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 used to switch on or off the energy dissipation branch 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, and then execute 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] The 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 method for testing the dynamic performance 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] The fourth aspect of the present application provides a computer-readable storage medium, which is used to store program codes, and the program codes are used to execute the dynamic performance test method of the energy self-balancing flexible straight valve energy release branch described in the first aspect above.

[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, the method simulates the overall overpressure 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 sub-module energy discharge branch actions in the energy self-balancing flexible direct current valve, and verifies the pressure equalization, resistance energy balance, and energy tolerance between the sub-modules. This 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 sub-modules as a whole, and the energy discharge branch is uniformly triggered, which is easy to oscillate during the overall action of the energy discharge branch, thereby causing the system protection to trip, and 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, and has the advantages of low investment and simple test methods. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 A schematic 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 structure 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 It 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 enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0061] See also Figure 1In the embodiment of the present application, a method for testing the dynamic performance of an energy self-balancing flexible direct current valve energy discharge branch is provided. 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. The test system includes: a DC voltage source, a test valve and a source module. When the whole is over-voltage, the energy discharge branch of the bridge arm submodule is actively put into use, 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; 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 connecting 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 the dynamic performance test of the energy self-balancing flexible straight valve energy release branch is started, that is, before the energy self-balancing flexible straight valve assembly is connected to the test system as a test valve, the test parameters of the test valve need to be 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 , 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 engineering to which the test valve belongs.

[0066] Step 102: 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.

[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 bridge arm 1 and the 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 : By adjusting the modulation wave amplitude of bridge arm 1 , the voltage of the submodule where the test valve is located is raised.

[0071] In one embodiment, step 103 includes:

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

[0073] in, ,satisfy ;

[0074] In the formula, and are the modulation wave amplitudes of the bridge arms, is the input voltage, is the rated working voltage.

[0075] It can be understood 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 , according to the average voltage of the submodule where the test valve is located, the energy discharge branch is switched on or off, and the modulation wave phase angle and the modulation wave amplitude of the bridge arm 1 are adjusted at the same time, and then step 105 is executed.

[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 uniformly triggers the energy release branch of the test valve, and sets the modulation wave phase angle difference θ of bridge arm 2 to 0, and decreases 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 uniformly closes 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 performs the sub-module switching and energy dissipation resistor switching actions 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] Based on the average absorbed energy calculation formula, calculate the average absorbed energy of the energy dissipation resistor;

[0085] The average absorbed energy calculation formula is:

[0086] ;

[0087] In the formula, 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, the step 105 of calculating the voltage imbalance of the submodule where the test valve is located and the absorption energy imbalance of the energy dissipation resistor 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 of voltage imbalance is:

[0092] ;

[0093] In the formula, is the voltage imbalance of the submodule where the test valve is located, is the highest voltage of the test valve module, is the minimum voltage of the test valve module, is the average voltage;

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

[0095] ;

[0096] In the formula, is the imbalance of energy absorption of the energy dissipation resistor, The maximum energy absorbed by the test valve module. 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 direct 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 submodule is detected to be less than 10% during the action of the energy release branch, and the energy absorption imbalance of the energy release resistor of the test valve submodule 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 a description of the test results obtained according to the test method of this application:

[0102] like Figure 4As shown, the first window above is the voltage of the bridge arm of the test valve (red) and the bridge arm voltage of the accompanying test valve (black). The start time of the dynamic performance test of the energy discharge branch is 3s. Before 3s, both bridge arms output 4 levels (modulation wave amplitude is 4). After the dynamic performance test of the energy discharge branch is started at 3s, within 20ms, the modulation wave amplitude of the bridge arm of the accompanying test valve is adjusted to 6, and the bridge arm outputs 6 levels at most to charge the test valve module. The upper right corner of the first window is the enlarged waveform at 3s, showing the change process of the level number. The second window is the bridge arm current, which runs at the maximum current continuous operation condition before 3s and after 3.6s. Between 3s and 3.6s, due to the action of the energy discharge branch, the phase angle is adjusted, and the bridge arm current is reduced. The third window is the capacitor voltage of the test valve module. It can be seen that it starts to rise at 3s and reaches a maximum of 3050V when the energy discharge branch is activated. The fourth window is the energy discharge branch conduction instruction. The system remains in operation during the test. This effect diagram only shows the change process of electrical quantity during 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, the submodule voltage and energy dissipation resistor absorption energy imbalance effect diagram obtained according to the test method provided by the present application, the submodule voltage imbalance during the energy dissipation branch action is less than 3.5%, and the energy dissipation resistor absorption energy imbalance of the test valve submodule after the test is less than 7.0%, and the dynamic performance of the energy dissipation branch of the test valve is determined to be qualified. According to the test method provided by the present invention, the entire test process verifies the dynamic performance of the energy dissipation 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 release branch. Based on the existing flexible direct current converter valve operation test system, the present application simulates the overall overpressure 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 submodule energy release branch actions in the energy self-balancing flexible direct current valve, and verifies the pressure equalization, resistance energy balance, and energy tolerance between the submodules. This makes up for the lack of effective testing methods during the action of the energy self-balancing flexible direct current valve energy release branch, and solves the problem that the existing operation test system cannot raise the voltage of the energy self-balancing flexible direct current valve submodules as a whole, and the energy release branch is uniformly triggered, which is prone to oscillation during the overall action of the energy release 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.

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

[0106] See also Figure 2 , a dynamic performance test device for an energy self-balancing flexible direct current valve energy discharge branch provided in an embodiment of the present application, 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 the test system as a test valve, and the submodule in the energy self-balancing flexible direct current valve is built-in with a control device having a function of detecting operating parameters and a valve control having a calculation and control function, wherein the test system 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;

[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 on or off the energy release branch 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, and then execute 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 energy self-balancing flexible straight valve energy release branch dynamic performance test device is provided in an embodiment of the present application, and the device includes 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 energy self-balancing flexible straight valve energy release branch dynamic performance test method as described in the above method embodiment according to the instructions in the program code.

[0117] Furthermore, a computer-readable storage medium is provided in an embodiment of the present application, and the computer-readable storage medium 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 can clearly understand that, for the convenience and brevity of description, the specific working processes of the systems and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0119] The terms "first", "second", "third", "fourth", etc. (if any) in the specification of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[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 may 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 objects associated before and after are in an "or" relationship. "At least one of the following" 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 multiple.

[0121] In the several embodiments provided in the present 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 only schematic. For example, the division of the units is only a logical function division. There may be other division methods in actual implementation, 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 separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed on multiple network units. Some or all of the units may be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0123] In addition, each functional unit in each embodiment of the present application may be integrated into one processing unit, or each unit may exist physically separately, or two or more units may be integrated into one unit. The above-mentioned integrated unit may be implemented in the form of hardware or in the form of 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 is essentially 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, including several instructions to enable 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 in English: Read-Only Memory, English abbreviation: ROM), random access memory (full name in English: Random Access Memory, English abbreviation: RAM), disk or optical disk and other media that can store program codes.

[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 aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned 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 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. The test system 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; 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 u , cut-off voltage U d , the maximum absorbed energy E of the energy dissipation resistor smu ; S2, by setting the operating parameters of the bridge arm 1 and the bridge arm 2, the bridge arm 2 operates in a maximum current continuous operating condition; S3, by adjusting the modulation wave amplitude of the bridge arm 1, the voltage of the submodule where the test valve is located is raised; S4, according to the average voltage of the submodule where the test valve is located, the energy dissipation branch is switched on or off, and the modulation wave phase angle and the modulation wave amplitude of the bridge arm 1 are adjusted at the same time, and then step S5 is executed; 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 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 S2 comprises: By assuming that the modulation wave amplitudes of the bridge arm 1 and the bridge arm 2 are both 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 ; In the formula, and are the modulation wave amplitudes of the bridge arms, is the input voltage, is the rated operating voltage.

4. The method for testing the dynamic performance of the energy self-balancing flexible straight valve energy release branch according to claim 2 is characterized in that: Step S4 comprises: 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 decreases 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 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 method for testing the dynamic performance 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 comprises: Based on the average absorbed energy calculation formula, the average absorbed energy of the energy dissipation resistor is calculated; Wherein, the average absorbed energy calculation formula is: ； In the formula, 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 method for testing the dynamic performance 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 absorption imbalance calculation formula of the energy dissipation resistor; The voltage imbalance calculation formula is: ； In the formula, is the voltage imbalance of the submodule where the test valve is located, is the highest voltage of the test valve module, is the minimum 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: ； In the formula, is the unbalanced degree of energy absorption of the energy dissipation resistor, The maximum energy absorbed by the test valve module. 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 comprises: 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 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. The test system 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; 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 raise 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 used to switch on or off the energy dissipation branch 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, and then execute 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 comprises 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 1-7 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 codes, and the program codes are 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 1-7.

Images