Fault detection method and device of energy storage converter and computer equipment

Abstract

The invention relates to a fault detection method and device for an energy storage converter and computer equipment. The method comprises the following steps: determining resistance information and inductance information of the energy storage converter, converter three-phase voltage information output by the energy storage converter and power grid three-phase voltage information of a power grid accessed by the energy storage converter; detecting the output voltage of each power unit to obtain the voltage information of the power unit; according to the resistance information, the inductance information, the three-phase voltage information of the converter, the three-phase voltage information of the power grid and the voltage information of the power units, theoretical inductive current information output by each power unit is predicted; according to the difference between the theoretical inductive current information and the actual inductive current information of all the power units, fault detection is carried out on the multiple power units in the energy storage converter, and fault detection results are obtained. By adopting the method, the fault detection of the energy storage converter can be efficiently carried out.

Description

Technical Field

[0001] This application relates to the technical field of fault detection, and particularly to a fault detection method, device, and computer device for an energy storage converter. Background Art

[0002] The energy storage converter is a key interface connecting the energy storage system and the microgrid, capable of realizing the transmission and conversion of electric energy, and playing a very important role in the normal operation of power work. Therefore, the fault detection of the energy storage converter is particularly important.

[0003] Currently, the general method for fault detection of an energy storage converter is: measuring the three-phase current of the energy storage converter, extracting the information of each frequency band in the three-phase current through wavelet analysis, detecting the current value in a specific frequency band to determine whether a fault occurs in the power unit of the energy storage converter, and then judging the fault detection result of the energy storage converter based on the fault detection result of the power unit in the energy storage converter.

[0004] However, the current fault detection method for the energy storage converter has the problem of low efficiency. Summary of the Invention

[0005] Based on this, it is necessary to provide an efficient fault detection method, device, computer device, computer-readable storage medium, and computer program product for the energy storage converter in view of the above technical problems.

[0006] In a first aspect, this application provides a fault detection method for an energy storage converter, including:

[0007] Determine the resistance information and inductance information of the energy storage converter, the three-phase converter voltage information output by the energy storage converter, and the three-phase grid voltage information of the grid to which the energy storage converter is connected, where the energy storage converter includes multiple power units;

[0008] Detect the output voltage of each power unit to obtain power unit voltage information;

[0009] According to the resistance information and inductance information, the three-phase converter voltage information, the three-phase grid voltage information, and the power unit voltage information, respectively predict the theoretical inductive current information output by each power unit;

[0010] Obtain the actual inductive current information output by each power unit;

[0011] According to the differences between the theoretical inductive current information and the actual inductive current information of all power units, respectively perform fault detection on multiple power units in the energy storage converter to obtain a fault detection result.

[0012] In a second aspect, this application also provides a fault detection device for an energy storage converter, including:

[0013] The first data acquisition module is configured to determine the resistance information and inductance information of the energy storage converter, the three-phase converter voltage information output by the energy storage converter, and the three-phase grid voltage information of the grid to which the energy storage converter is connected. The energy storage converter includes a plurality of power units.

[0014] The second data acquisition module is configured to detect the output voltage of each power unit to obtain power unit voltage information.

[0015] The current prediction module is configured to respectively predict the theoretical inductor current information output by each power unit according to the resistance information and inductance information, the three-phase converter voltage information, the three-phase grid voltage information, and the power unit voltage information.

[0016] The actual current acquisition module is configured to obtain the actual inductor current information output by each power unit.

[0017] The fault detection module is configured to respectively perform fault detection on a plurality of power units in the energy storage converter according to the difference between the theoretical inductor current information and the actual inductor current information of all power units, and obtain a fault detection result.

[0018] In a third aspect, the present application further provides a computer device, including a memory and a processor. The memory stores a computer program, and when the processor executes the computer program, the following steps are implemented:

[0019] Determine the resistance information and inductance information of the energy storage converter, the three-phase converter voltage information output by the energy storage converter, and the three-phase grid voltage information of the grid to which the energy storage converter is connected. The energy storage converter includes a plurality of power units.

[0020] Detect the output voltage of each power unit to obtain power unit voltage information.

[0021] Respectively predict the theoretical inductor current information output by each power unit according to the resistance information and inductance information, the three-phase converter voltage information, the three-phase grid voltage information, and the power unit voltage information.

[0022] Obtain the actual inductor current information output by each power unit.

[0023] Respectively perform fault detection on a plurality of power units in the energy storage converter according to the difference between the theoretical inductor current information and the actual inductor current information of all power units, and obtain a fault detection result.

[0024] In a fourth aspect, the present application further provides a computer-readable storage medium, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0025] Determine the resistance information and inductance information of the energy storage converter, the three-phase converter voltage information output by the energy storage converter, and the three-phase grid voltage information of the grid to which the energy storage converter is connected. Among them, the energy storage converter includes multiple power units;

[0026] Detect the output voltage of each power unit to obtain power unit voltage information;

[0027] According to the resistance information and inductance information, the three-phase converter voltage information, the three-phase grid voltage information, and the power unit voltage information, respectively predict the theoretical inductance current information output by each power unit;

[0028] Obtain the actual inductance current information output by each power unit;

[0029] According to the differences between the theoretical inductance current information and the actual inductance current information of all power units, respectively perform fault detection on multiple power units in the energy storage converter to obtain a fault detection result.

[0030] In a fifth aspect, the present application also provides a computer program product, including a computer program, which when executed by a processor implements the following steps:

[0031] Determine the resistance information and inductance information of the energy storage converter, the three-phase converter voltage information output by the energy storage converter, and the three-phase grid voltage information of the grid to which the energy storage converter is connected. Among them, the energy storage converter includes multiple power units;

[0032] Detect the output voltage of each power unit to obtain power unit voltage information;

[0033] According to the resistance information and inductance information, the three-phase converter voltage information, the three-phase grid voltage information, and the power unit voltage information, respectively predict the theoretical inductance current information output by each power unit;

[0034] Obtain the actual inductance current information output by each power unit;

[0035] According to the differences between the theoretical inductance current information and the actual inductance current information of all power units, respectively perform fault detection on multiple power units in the energy storage converter to obtain a fault detection result.

[0036] The above-mentioned fault detection method, device, computer equipment, computer-readable storage medium and computer program product for an energy storage converter. Throughout the process, by combining the energy storage converter, the power units in the energy storage converter, and the power grid to which the energy storage converter is connected, and then using the resistance information and inductance information of the energy storage converter, the three-phase converter voltage information output by the energy storage converter, the three-phase grid voltage information of the power grid to which the energy storage converter is connected, and the power unit voltage information, the theoretical inductive current output by each power unit is predicted respectively. By combining the theoretical inductive current output by each power unit with the actual measured inductive current, and according to the differences between the theoretical inductive current information and the actual inductive current information of all power units, fault detection is performed on multiple power units in the energy storage converter respectively to obtain the fault detection result. This method is more convenient than the wavelet analysis method. Through the differences between the theoretical inductive current information and the actual inductive current information of all power units, fault detection of the energy storage converter can be performed online in real time, improving the efficiency of fault detection. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the following will briefly introduce the drawings required for use in the description of the embodiments of the present application or related technologies. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other related drawings can also be obtained based on these drawings.

[0038] Figure 1 It is an application environment diagram of the fault detection method for an energy storage converter in one embodiment;

[0039] Figure 2 It is a schematic flowchart of the fault detection method for an energy storage converter in one embodiment;

[0040] Figure 3 It is a schematic diagram of discrete control of phase A in one embodiment;

[0041] Figure 4 It is a schematic flowchart of the fault detection method for an energy storage converter in another embodiment;

[0042] Figure 5 It is a schematic diagram of the mapping relationship between the preset current residual information and the fault location results of the three-phase bridge arms in the energy storage converter in one embodiment;

[0043] Figure 6 It is a schematic diagram of the current residual vector of the energy storage converter in one embodiment;

[0044] Figure 7 It is a schematic diagram of the change of the power unit current when an open-circuit fault occurs in the upper bridge arm of phase C in one embodiment;

[0045] Figure 8 Schematic diagram of the current residual change of each phase before and after a fault occurs in an embodiment;

[0046] Figure 9 Schematic diagram of the current fluctuation of the power unit before and after a fault in an embodiment;

[0047] Figure 10 Fault detection method for the SiC MOSFET power unit in the energy storage converter in a specific application example;

[0048] Figure 11 Structural block diagram of the fault detection device for the energy storage converter in an embodiment;

[0049] Figure 12 Internal structure diagram of a computer device in an embodiment. Detailed implementation manners

[0050] In order to make the objectives, technical solutions and advantages of the present application clearer and more understandable, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are used to explain the present application and are not used to limit the present application.

[0051] The energy storage converter is a key interface connecting the energy storage system and the microgrid, capable of realizing the transmission and conversion of electric energy. It has multiple functions such as load control, peak shaving and valley filling, emergency power supply, grid connection and disconnection switching, island operation and grid forming. In the context of the increasing development of new energy power generation, the energy storage converter has become one of the core devices for the future development of the power system.

[0052] The new power system with a high proportion of new energy and a high proportion of power electronic devices is an important means to achieve the "dual carbon" goal. With the promotion of the "dual carbon" goal, the energy storage converter is tending to develop towards large capacity and modularization, and its structure usually adopts the design based on the DC (Direct Current) / AC (Alternating Current) converter. In terms of the selection of the power unit of the energy storage converter, compared with the silicon IGBT (Insulated Gate Bipolar Transistor), the silicon MOSFET has a higher switching frequency, lower switching loss and higher operating junction temperature. However, due to the limitations of the silicon material characteristics, the development of silicon-based devices has approached a bottleneck. Therefore, the silicon carbide (SiC) device has become an important future development direction. Compared with the silicon material, the SiC device shows significant advantages in terms of energy loss, heat management, operating frequency and current density. Under the same power condition, its volume is smaller and it is more suitable for high-frequency application scenarios.

[0053] Due to the high switching speed of SiC power units, compared with traditional IGBTs, they generate higher di / dt (how much the current changes per unit time) and du / dt (how much the voltage changes per unit time). This characteristic may lead to problems such as higher turn-off overvoltage, more significant switching oscillations, and higher operating temperatures, making SiC power units one of the vulnerable links prone to failures in energy storage converters. Therefore, by online real-time diagnosing the faults of power units in energy storage converters, that is, detecting the faults of energy storage converters and taking timely and appropriate fault-tolerant control strategies to improve the operating stability and reliability of energy storage converters, this has important theoretical significance and engineering application value.

[0054] Currently, the general method for fault detection of energy storage converters is: measure the three-phase current of the energy storage converter, extract the information of each frequency band in the three-phase current through wavelet analysis, and detect the current value in a specific frequency band to determine whether a fault occurs in the power unit of the energy storage converter, thereby realizing the fault detection of the energy storage converter. However, the current fault detection method for energy storage converters has the problem of low efficiency.

[0055] For this reason, this application provides a fault detection method for energy storage converters. Throughout the process, by combining the energy storage converter, the power units in the energy storage converter, and the power grid to which the energy storage converter is connected, and then using the resistance information and inductance information of the energy storage converter, the three-phase converter voltage information output by the energy storage converter, the three-phase grid voltage information of the power grid to which the energy storage converter is connected, and the power unit voltage information, respectively predict the theoretical inductive current output by each power unit. Combine the theoretical inductive current output by each power unit with the actually measured actual inductive current. According to the differences between the theoretical inductive current information and the actual inductive current information of all power units, respectively perform fault detection on multiple power units in the energy storage converter to obtain the fault detection result. This method is more convenient than the wavelet analysis method. Through the differences between the theoretical inductive current information and the actual inductive current information of all power units, the energy storage converter can be fault-detected online in real time, improving the efficiency of fault detection.

[0056] The fault detection method for energy storage converters provided by the embodiments of this application can be applied to the application environment as Figure 1 shown. Among them, the terminal 102 communicates with the fault detection system 104 through the network.

[0057] The user triggers a fault detection control on the fault detection interface of the terminal 102. The terminal 102 responds to the fault detection request and controls the fault detection system 104 to determine the resistance information and inductance information of the energy storage converter, the three-phase converter voltage information output by the energy storage converter, and the three-phase grid voltage information of the grid to which the energy storage converter is connected. Among them, the energy storage converter includes multiple power units; the output voltage of each power unit is detected to obtain power unit voltage information; according to the resistance information, inductance information, three-phase converter voltage information, three-phase grid voltage information, and power unit voltage information, the theoretical inductance current information output by each power unit is predicted respectively; the actual inductance current information output by each power unit is obtained, and based on the difference between the theoretical inductance current information and the actual inductance current information of all power units, fault detection is performed on multiple power units in the energy storage converter respectively to obtain a fault detection result. Further, the fault detection system 104 can also push the fault detection result of the energy storage converter to the fault detection interface of the terminal 102 for the terminal 102 to display to the user.

[0058] Among them, the terminal 102 can be, but is not limited to, various personal computers, laptop computers, smart phones, tablet computers, Internet of Things devices, and portable wearable devices. The Internet of Things devices can be smart speakers, smart TVs, smart air conditioners, smart in-vehicle devices, projection devices, etc. The portable wearable devices can be smart watches, smart bracelets, head-mounted devices, etc. The head-mounted device can be a virtual reality (VR) device, an augmented reality (AR) device, smart glasses, etc.

[0059] In an exemplary embodiment, as Figure 2 shown, a fault detection method for an energy storage converter is provided. Taking this method applied to Figure 1 the fault detection system 104 in it as an example for illustration. Among them:

[0060] S100, determine the resistance information and inductance information of the energy storage converter, the three-phase converter voltage information output by the energy storage converter, and the three-phase grid voltage information of the grid to which the energy storage converter is connected.

[0061] Among them, the energy storage converter refers to an interface connecting the energy storage system and the microgrid, and is a device that can realize the transmission and conversion of electric energy. The energy storage converter includes multiple power units.

[0062] Specifically, in the related art, during the fault detection of traditional energy storage converters, the power units of the grid and the energy storage converter cannot be unified in an analytical model. Therefore, the traditional model cannot accurately reveal the complete state characteristics of the energy storage converter and is not suitable for the analysis and diagnosis of internal faults of the power units of the energy storage converter.

[0063] Therefore, the present application makes certain improvements by combining the energy storage converter, the power grid, and the power units of the energy storage converter. By obtaining the resistance information and inductance information of the energy storage converter, the three-phase converter voltage information output by the energy storage converter, and the three-phase grid voltage information of the power grid to which the energy storage converter is connected, and combining with the voltage information of the power units of the energy storage converter, the complete state characteristics of the energy storage converter are obtained, enabling the energy storage converter, the power grid, and the power units of the energy storage converter to jointly participate in the fault detection process of the energy storage converter.

[0064] S200. Detect the output voltage of each power unit to obtain power unit voltage information.

[0065] Specifically, since the energy storage converter includes multiple power units, in order to obtain the voltage information of the power units, the present application can also detect the output voltage of each power unit to collect the detected output voltages of each power unit to obtain power unit voltage information.

[0066] S300. According to the resistance information, inductance information, three-phase converter voltage information, three-phase grid voltage information, and power unit voltage information, respectively predict the theoretical inductive current information output by each power unit.

[0067] Specifically, the energy storage converter, the power grid, and the power units of the energy storage converter are unified into an analysis model to obtain a hybrid logical dynamic model of the energy storage converter, which can accurately describe the complete state characteristics of the energy storage converter. Then, the resistance information, inductance information, three-phase converter voltage information, three-phase grid voltage information, and power unit voltage information are input into the hybrid logical dynamic model of the energy storage converter to generate the theoretical inductive current of the energy storage converter.

[0068] S400. Obtain the actual inductive current information output by each power unit.

[0069] S500. According to the differences between the theoretical inductive current information and the actual inductive current information of all power units, respectively perform fault detection on multiple power units in the energy storage converter to obtain a fault detection result.

[0070] Among them, in mathematical statistics, the residual refers to the difference between the actual observed value and the estimated value (fitted value).

[0071] Specifically, obtain the actual inductor current information output by each power unit. The theoretical inductor current information is the inductor current information calculated by the model, and the actual inductor current information is the inductor current information obtained through actual detection. When a fault occurs in the power unit of the energy storage converter, the discrete input quantity of the system will change. At this time, the theoretical inductor current will not be equal to the inductor current of the device. Therefore, the difference between the theoretical inductor current information and the actual inductor current information of each power unit can be obtained. Further, according to the differences between the theoretical inductor current information and the actual inductor current information of all power units, fault detection is performed on multiple power units in the energy storage converter respectively, and it can be more accurately judged whether there is a fault in the energy storage converter.

[0072] In an exemplary embodiment, according to the differences between the theoretical inductor current information and the actual inductor current information of all power units, fault detection is performed on multiple power units in the energy storage converter respectively. That is, obtain the theoretical inductor current values output by each power unit from the theoretical inductor current information output by each power unit, obtain the actual inductor current values output by each power unit from the actual inductor current information output by each power unit. For each power unit, generate a local current residual value between the theoretical inductor current value and the actual inductor current value according to the theoretical inductor current value and the actual inductor current value, and then perform fault detection on multiple power units in the energy storage converter respectively according to the local current residual values between the theoretical inductor current values and the actual inductor current values of all power units.

[0073] When the differences between the theoretical inductor current information and the actual inductor current information of the power units indicate that there are no faults in multiple power units in the energy storage converter, directly generate the fault detection result of the energy storage converter, and the generated fault detection result indicates that the energy storage converter has no fault; when the differences between the theoretical inductor current information and the actual inductor current information of all power units indicate that there is a fault in a power unit, further locate the faulty power unit according to the differences between the theoretical inductor current information and the actual inductor current information of all power units, generate the fault detection result of the energy storage converter, and the generated fault detection result indicates that there is a fault in a certain power unit in the energy storage converter.

[0074] In the above fault detection method for the energy storage converter, throughout the process, by combining the energy storage converter, the power units in the energy storage converter, and the power grid to which the energy storage converter is connected, and then using the resistance information and inductance information of the energy storage converter, the three-phase converter voltage information output by the energy storage converter, the three-phase grid voltage information of the power grid to which the energy storage converter is connected, and the power unit voltage information, the theoretical inductive current output by each power unit is predicted respectively. By combining the theoretical inductive current output by each power unit with the actual measured inductive current, and based on the differences between the theoretical inductive current information and the actual inductive current information of all power units, fault detection is performed on multiple power units in the energy storage converter respectively to obtain the fault detection result. This method is more convenient than the wavelet analysis method. Through the differences between the theoretical inductive current information and the actual inductive current information of all power units, the energy storage converter can be fault-detected online in real time, improving the efficiency of fault detection.

[0075] In an exemplary embodiment, before predicting the theoretical inductive current information output by each power unit according to the resistance information, inductance information, three-phase converter voltage information, three-phase grid voltage information, and power unit voltage information respectively, the method further includes:

[0076] Obtain the pre-constructed voltage continuous model of the energy storage converter; use the power unit voltage parameters of the power unit to correct the three-phase converter voltage parameters in the voltage continuous model to generate the hybrid logical dynamic model of the energy storage converter.

[0077] Among them, the voltage continuous model is composed of the resistance parameters and inductance parameters of the energy storage converter, the three-phase converter voltage parameters and three-phase converter current parameters output by the energy storage converter, and the three-phase grid voltage parameters of the power grid. The voltage continuous model is used to characterize the three-phase converter voltage output by the energy storage converter when the energy storage converter is connected to the power grid.

[0078] Specifically, the traditional equivalent linear model can only describe the performance of the energy storage converter macroscopically. Similarly, the switching function model does not consider the situation where the bridge arm power units are turned off simultaneously and cannot be used for analyzing the fault states of the power units. As an improvement, the present application will consider the energy storage converter, the power grid, and the power units simultaneously when constructing the hybrid logical dynamic model of the energy storage converter.

[0079] More specifically, in the process of constructing the hybrid logical dynamic model of the energy storage converter, first, consider the energy storage converter and the power grid simultaneously to generate the voltage continuous model of the energy storage converter. The voltage continuous model is used to characterize the three-phase converter voltage output by the energy storage converter when the energy storage converter is connected to the power grid. Furthermore, use the power unit voltage parameters of the power unit to correct the three-phase converter voltage parameters in the voltage continuous model, and finally generate the hybrid logical dynamic model of the energy storage converter.

[0080] In an exemplary embodiment, generating a voltage continuous model of a energy storage converter includes: obtaining a pre-built voltage continuous model of the energy storage converter, which is composed of the resistance parameter and inductance parameter of the energy storage converter, the three-phase voltage parameter and three-phase current parameter of the converter output by the energy storage converter, and the three-phase voltage parameter of the power grid.

[0081] For example, the circuit of the entire energy storage converter consists of three phases A, B, and C, and each phase is formed by superimposing 4 power units with the same functional structure and anti-parallel diodes. The output ends of the 4 power units in each phase are connected in sequence to form a series superposition method. By controlling the output of each power unit, a multi-step wave close to a sine wave can be obtained after superposition. Taking phase A as an example, the discrete control schematic diagram of phase A is as Figure 3 shown, where 1001, 1002, 1003, and 1004 are 4 power units with the same functional structure, 1006 and 1007 are anti-parallel diodes, 1008 is the resistance of the energy storage converter, and 1009 is the inductance of the energy storage converter.

[0082] At this time, the pre-built voltage continuous model of the energy storage converter can be expressed as:

[0083]

[0084] Wherein, , and are the three-phase current parameters of the converter output by the energy storage converter. n is a relay point in the energy storage converter. a, b, and c are points on the bridge arms of phases A, B, and C respectively. , and are the three-phase voltage parameters of the equipment between points a, b, and c on the three-phase bridge arm of the energy storage converter output and the relay point n respectively. , and are the three-phase voltage parameters of the power grid. is the resistance parameter of the energy storage converter. is the inductance parameter of the energy storage converter.

[0085] When , let be 0, otherwise let be 1. , where is an intermediate variable related to this i kn . At this time, since there are 12 power units, the three-phase three-level energy storage converter has a total of 12 discrete control variables and , , There are 3 discrete conditional variables, a total of 15 logical variables, and there are possible operating states. After removing the invalid operating states, the power unit voltage parameters of the power unit are obtained, including:

[0086]

[0087] Among them, u ko is the power unit voltage parameter of phase A between point a and point o on the phase A bridge arm, u ko is the power unit voltage parameter of phase B between point b and point o on the phase B bridge arm, u ko is the power unit voltage parameter of phase C between point c and point o on the phase C bridge arm. Phase A corresponds to four discrete control variables s1~s4 respectively, phase B corresponds to four discrete control variables s5~s8 respectively, and phase C corresponds to four discrete control variables s9~s12 respectively.

[0088] In an exemplary embodiment, using the power unit voltage parameters of the power unit to correct the three-phase voltage parameters of the converter in the voltage continuous model, a hybrid logical dynamic model of the energy storage converter is generated, including: combining the voltage continuous model with the power unit voltage parameters of the power unit to obtain the relationship between in the energy storage converter and in the power unit is:

[0089]

[0090] Substituting the above u into the voltage continuous model of the energy storage converter, the constructed hybrid logical dynamic model of the energy storage converter is:

[0091]

[0092] In an exemplary embodiment, the hybrid logical dynamic model can also be converted into a vector form, and its specific expression is: .

[0093] According to the resistance information and inductance information, the three-phase voltage information of the converter, the three-phase voltage information of the power grid, and the power unit voltage information, the theoretical inductance current information output by each power unit is predicted respectively, and it also includes:

[0094] Taking the resistance information and inductance information, the three-phase voltage information of the converter, the three-phase voltage information of the power grid, and the power unit voltage information as the model input, and using the hybrid logical dynamic model to predict the theoretical inductance current of the energy storage converter.

[0095] Specifically, the hybrid logic dynamic model of the energy storage converter at this time simultaneously considers the resistance parameter and inductance parameter of the energy storage converter, the three-phase converter voltage parameter and three-phase converter current parameter output by the energy storage converter, the three-phase grid voltage parameter of the grid, and the power unit voltage parameter of the power unit. Therefore, the resistance information corresponding to the resistance parameter, the inductance information corresponding to the inductance parameter, the three-phase converter voltage information corresponding to the three-phase converter voltage parameter and the three-phase converter current information corresponding to the three-phase converter current parameter, the three-phase grid voltage information corresponding to the three-phase grid voltage parameter, and the power unit voltage information corresponding to the power unit voltage parameter can be obtained, and the resistance information, inductance information, three-phase converter voltage information, three-phase grid voltage information, and power unit voltage information are used as the model inputs. Using the hybrid logic dynamic model, the theoretical inductance current of the energy storage converter can be predicted.

[0096] In the above embodiment, by combining the energy storage converter, the grid, and the power unit, the hybrid logic dynamic model of the energy storage converter can be accurately constructed to accurately obtain the complete state characteristics of the energy storage converter, so that the resistance information, inductance information, three-phase converter voltage information, three-phase grid voltage information, and power unit voltage information can be used as the model inputs, and the hybrid logic dynamic model can be used to accurately predict the theoretical inductance current of the energy storage converter.

[0097] In an exemplary embodiment, the energy storage converter includes a three-phase bridge arm, as Figure 4 shown, S500, including:

[0098] S510, generates local current residual information corresponding to each phase bridge arm in the three-phase bridge arm according to the difference between the theoretical inductance current information and the actual inductance current information of all power units.

[0099] S520, detects whether a power unit in the energy storage converter fails according to the correlation relationship between the local current residual information corresponding to each phase bridge arm.

[0100] S530, in the case of detecting that a power unit in the energy storage converter fails, locates the target phase bridge arm with a faulty power unit from each phase bridge arm according to the local current residual information corresponding to each phase bridge arm.

[0101] S540, generates current residual information of the energy storage converter according to the local current residual information corresponding to each phase bridge arm, and locates the target power unit with a fault from the target phase bridge arm according to the current residual information.

[0102] Specifically, local current residual information corresponding to each phase bridge arm in the three-phase bridge arm is generated according to the difference between the theoretical inductance current information and the actual inductance current information of all power units 、 , . Among them, is the local current residual information of the A-phase bridge arm, is the local current residual information of the B-phase bridge arm, is the local current residual information of the C-phase bridge arm.

[0103] Furthermore, according to the correlation relationship between the local current residual information corresponding to each phase bridge arm, it is determined whether there is a faulty power unit in the energy storage converter. For example, according to the sum of the local current residual values corresponding to the local current residual information of each phase bridge arm, it is detected whether the power unit in the energy storage converter fails. Another example is to detect whether the power unit in the energy storage converter fails according to the corresponding relationship between a certain local current residual value and other local current residual values.

[0104] When it is detected that the power unit in the energy storage converter fails, according to the local current residual information corresponding to each phase bridge arm, the faulty phase bridge arm is located from each phase bridge arm, that is, the target phase bridge arm where the faulty power unit exists is located.

[0105] After the target phase bridge arm where the faulty power unit exists is located from each phase bridge arm, at this time, the current residual information of the energy storage converter can be generated according to the local current residual information corresponding to each phase bridge arm, and the target power unit with a fault can be located from the target phase bridge arm according to the current residual information.

[0106] It should be explained that the reason for not directly locating the target power unit with a fault from the three-phase bridge arm through the current residual information is that in this embodiment, the faults of the energy storage converter are accurately detected by the method of first diagnosing and then locating. That is to say, first, it is necessary to determine whether each phase bridge arm of the energy storage converter fails through the local current residual information corresponding to each phase bridge arm. Secondly, when one phase bridge arm of the energy storage converter fails, the target power unit with a fault is located from the target phase bridge arm through the current residual information, and the local current residual information is the difference between the theoretical inductor current and the actual inductor current of each phase bridge arm, and the process of obtaining this difference is simpler and more efficient.

[0107] In some other embodiments, when it is determined through the local current residual information corresponding to each phase bridge arm that each phase bridge arm of the energy storage converter does not fail, the subsequent fault location process can be omitted. That is to say, when it is determined through the local current residual information corresponding to each phase bridge arm that each phase bridge arm of the energy storage converter does not fail, the process of generating the current residual information of the energy storage converter according to the local current residual information corresponding to each phase bridge arm does not need to be executed.

[0108] In an exemplary embodiment, the hybrid logic dynamic model is converted into a vector form as follows: Then, the local current residual information between the theoretical inductor current information and the actual inductor current information of the power units in each phase is Furthermore, based on the local current residual information corresponding to each phase leg, the current residual information of the energy storage converter is generated as where is the local current residual information corresponding to phase A, is the local current residual information corresponding to phase B, is the local current residual information corresponding to phase C.

[0109] In other embodiments, the target phase leg with a fault and the target power unit with a fault can also be located directly from the three-phase legs according to the current information of each phase leg.

[0110] Specifically, the upper leg fault of the current fault phase corresponds to the negative half-cycle of the axis of this phase, the lower leg fault of the fault phase corresponds to the positive half-cycle of the axis of this phase, and the trajectory moves along the entire axis of this phase when both the upper and lower tubes are open-circuited. When the amplitude information and phase information of the current information of the target phase leg characterize that the current information moves along the negative half-cycle of the coordinate system corresponding to the current information, it is located that the power unit of the upper leg of the target phase leg has an open-circuit fault; when the amplitude information and phase information characterize that the current information moves along the positive half-cycle of the coordinate system corresponding to the current information, it is located that the power unit of the lower leg of this phase leg has an open-circuit fault. When the local current residual information of the target phase leg characterizes the movement along the entire axis of the target phase, at this time, the power units of both the upper and lower legs of the target phase have open-circuit faults simultaneously.

[0111] In the above embodiment, first, according to the correlation relationship between the local current residual information corresponding to each phase leg, it is detected whether the power units in the energy storage converter are faulty. In the case where it is detected that the power units in the energy storage converter are faulty, only then based on the local current residual information corresponding to each phase leg, the target phase leg with the faulty power unit is located from each phase leg. Finally, after determining the target phase leg with the faulty power unit, further based on the local current residual information corresponding to each phase leg, the current residual information of the energy storage converter is generated, and based on the current residual information, the target power unit with a fault is located from the target phase leg, and the analysis is carried out layer by layer. The process is more simple and efficient, and the target phase leg with the faulty power unit and the target power unit with a fault can be accurately located.

[0112] In an exemplary embodiment, detecting whether the power units in the energy storage converter are faulty according to the correlation relationship between the local current residual information corresponding to each phase leg includes:

[0113] According to the local current residual information corresponding to each phase bridge arm, obtain the local current residual value corresponding to each phase bridge arm; when the sum of the local current residual values corresponding to all phase bridge arms is a preset value, it is detected that the power unit in the energy storage converter does not fail; when the sum of the local current residual values corresponding to all phase bridge arms is not the preset value, and there is any target phase bridge arm among the three-phase bridge arms whose corresponding local current residual value is consistent with and has the opposite sign to the sum of the local current residual values corresponding to the other two phase bridge arms except the target phase bridge arm, it is detected that the power unit of the target phase bridge arm fails.

[0114] Among them, the preset value in this application is 0.

[0115] Specifically, obtain the local current residual value corresponding to each phase bridge arm from the local current residual information corresponding to each phase bridge arm. According to the correlation relationship between the local current residual information corresponding to each phase bridge arm, detect whether the power unit in the energy storage converter fails, and its correlation relationship includes the sum of the local current residual information corresponding to all phase bridge arms + + , and the relationship between the local current residual information corresponding to any one phase bridge arm and the sum of the local current residual information corresponding to the other two phase bridge arms.

[0116] When the sum of the local current residual information corresponding to all phase bridge arms is 0, that is, when + + = 0, it is considered that the theoretical inductance current information output by the power unit of this phase bridge arm is consistent with the actual inductance current information, indicating that the power unit of this phase bridge arm does not fail.

[0117] When the sum of the local current residual information corresponding to all phase bridge arms is not 0, it is considered that the theoretical inductance current information output by the power unit of this phase bridge arm is inconsistent with the actual inductance current information, indicating that the power unit of this phase bridge arm may fail and needs further analysis.

[0118] Immediately afterwards, detect whether there is any target phase bridge arm among the three-phase bridge arms whose corresponding local current residual value is consistent with and has the opposite sign to the sum of the local current residual values corresponding to the other two phase bridge arms except the target phase bridge arm. For example, detect whether there is - = + , and again, detect whether there is - = + , detect whether there is - = + etc.

[0119] When the local current residual value corresponding to any target phase leg is consistent with and has the opposite sign to the sum of the local current residual values corresponding to the other two phase legs except the target phase leg, it is considered that a fault has occurred in the power unit in the detected target phase leg. That is to say, the current residual of the faulty phase leg in the energy storage converter will be equal to the sum of the current residuals of the two non-faulty phase legs, and have the opposite sign. For example, in the presence of = + it is considered that a fault has occurred in the power unit in Phase A leg.

[0120] For example, when a fault occurs in the upper arm of Phase A, s1 and s2 are always 0, where the power unit in the upper layer is the lower arm and the power unit in the lower layer is the upper arm. Substituting s1 and s2 = 0 into the residual equation and solving, the current residuals of the three phases of the converter can be obtained as:

[0121]

[0122] Similarly, the current residuals of the three phases of the converter when a fault occurs in the lower arm of Phase A are:

[0123]

[0124] It can be seen that the current residual of the faulty phase in the energy storage converter will be equal to the sum of the current residuals of the two non-faulty phases, and have the opposite sign.

[0125] In the above embodiments, when the sum of the local current residual values corresponding to all phase legs is a preset value, it is detected that no fault has occurred in the power unit in the energy storage converter; when the sum of the local current residual values corresponding to all phase legs is not the preset value, and there is any target phase leg corresponding to the local current residual value that is consistent with and has the opposite sign to the sum of the local current residual values corresponding to the other two phase legs except the target phase leg, it is detected that a fault has occurred in the power unit of the target phase leg. By based on the correlation relationship between the local current residual information corresponding to each phase leg, it is possible to accurately determine whether a fault has occurred in the power unit in the energy storage converter, and the process is more accurate.

[0126] In an exemplary embodiment, the current residual information includes a current residual vector. According to the current residual information, to locate the target power unit with a fault from the target phase leg includes:

[0127] Obtain the amplitude information and phase information of the current residual vector; according to the amplitude information and phase information, locate the target power unit with a fault from the target phase leg.

[0128] Specifically, traditional fault detection methods can only determine whether a power unit has a fault, but cannot locate the faulty power unit to perform fault-tolerant control on the faulty power unit to improve the robustness of the system. This application has made certain improvements in this regard. Through the amplitude information and phase information of the current residual vector, deeper fault detection can be performed on the three-phase bridge arms to locate the target power unit with a fault from the target phase bridge arm.

[0129] In the above embodiment, through the amplitude information and phase information of the local current residual information, accurate fault detection can be performed on the power unit to accurately locate the target power unit with a fault from the target phase bridge arm, and then perform fault-tolerant control on the faulty power unit in a timely manner.

[0130] In an exemplary embodiment, locating the target power unit with a fault from the target phase bridge arm according to the amplitude information and phase information of the current residual vector includes:

[0131] Obtain the mapping relationship between the preset amplitude information and phase information of the current residual vector and the fault location results of multiple power units in the energy storage converter; according to the mapping relationship, detect the fault detection results of multiple power units in the energy storage converter that match the amplitude information and phase information.

[0132] Specifically, the mapping relationship between the current residual information and the fault location results of the three-phase bridge arms in the energy storage converter is preset in advance as Figure 5 shown. In the case where the current residual information is as Figure 6 shown, according to the amplitude information and phase information of the current residual information, match the current residual information with the mapping relationship. If it is determined that the current residual vector moves along the axis matching the upper bridge arm of the target phase bridge arm, then at this time, it is located that the power unit of the upper bridge arm of the target phase bridge arm has an open circuit fault. Similarly, according to the amplitude information and phase information of the current residual information, match the current residual information with the mapping relationship. If it is determined that the current residual vector moves along the axis matching the lower bridge arm of the target phase bridge arm, then at this time, it is located that the power unit of the lower bridge arm of the target phase bridge arm has an open circuit fault. Further, the accuracy of fault detection can be improved by increasing the amplitude threshold and phase threshold limits of the current residual information.

[0133] Based on the above analysis, to prove the effectiveness of the method of this application, software simulation can be used for verification.

[0134] Taking the power unit as a SiC MOSFET power unit as an example, the fault location judgment diagram of the SiC MOSFET power unit in the energy storage converter is still referred to as Figure 5, the energy storage converter includes phases A, B, and C, and each phase has upper and lower bridge arms. Among them, the DC bus voltage is 1500V, the rated power is 100kW, the amplitude threshold of the current residual vector is set to 1A, and the phase threshold of each phase is 60 degrees.

[0135] To verify the performance of the system, software is used to simulate an open-circuit fault of the power unit in the upper bridge arm of phase C. The fault time is 0.55s. The system operates normally before 0.55s. From Figure 7 it can be seen that after the power unit in the upper bridge arm of phase C fails, the three-phase current waveforms are significantly distorted, and the sinusoidality of the three-phase currents becomes worse. Because the power unit in the upper bridge arm of phase C fails, there is a negative half-cycle part in the current of phase C. From Figure 8 it can be seen that before the fault occurs, the three-phase currents calculated by the hybrid logic dynamic model are the same as the actual three-phase currents. After the fault occurs, the three-phase currents calculated by the model differ greatly from the actual three-phase currents, and the equation relationship that the current of the faulty phase C is the sum of the currents of the non-faulty phases A and B is satisfied. The current residual vector is still as Figure 6 shown. From Figure 6 it can be seen that after the fault occurs, the phase of the current residual vector is 60 degrees and is located in the fault area of the upper bridge arm of phase C. Therefore, it can be determined that the fault is the fault of the upper bridge arm of phase C, and the fault location function is realized.

[0136] In an exemplary embodiment, to detect whether a power unit in the energy storage converter fails, it can be detected not only based on the correlation relationship between the local current residual information corresponding to each phase bridge arm, but also directly based on the amplitude information and phase information of the current residual information. For example, when there is no open-circuit fault in the power unit of the energy storage converter, the amplitude information and phase information of the current residual information indicate that the current residual information is at the origin.

[0137] In the above embodiment, by directly comprehensively analyzing the amplitude information and phase information of the current residual vector, the faulty bridge arm of each phase can be accurately located, and the process is simple and efficient.

[0138] In an exemplary embodiment, the fault detection method of the energy storage converter further includes:

[0139] When the fault detection result indicates that there is an open-circuit fault in the power unit of the target phase bridge arm, control the bidirectional thyristor of the target phase bridge arm to conduct. Among them, the bidirectional thyristor after conduction is used to replace the faulty target phase bridge arm with the standby phase bridge arm and connect it to the working circuit of the energy storage converter.

[0140] Specifically, after an open - circuit fault occurs in the power unit of the target phase leg, fault - tolerant control is required to improve the system stability. As an improvement, when the fault detection result indicates that an open - circuit fault occurs in the power unit of the target phase leg, the bidirectional thyristor of the target phase leg is controlled to conduct, so that the standby phase leg replaces the faulty target phase leg and is connected to the working circuit of the energy storage converter, thereby ensuring the stable operation of the system after the fault and solving the problem of current fluctuation after the fault. Similarly, when a short - circuit fault occurs in the power unit of the target phase leg, the above - mentioned method can also be used to ensure the stable operation of the system after the fault, which will not be elaborated here.

[0141] In an exemplary embodiment, referring to Figure 9 , according to the fault location result, it is known that the fault is in the upper bridge arm of phase C. The control system cuts off the faulty upper bridge arm of phase C and connects phase C to the standby bridge arm. After the connection, the system operates stably, improving the robustness of the system. Moreover, the entire switching process is less than one - quarter of the fundamental wave period, and the action time is short, meeting the requirement of rapidity.

[0142] In the above - mentioned embodiment, by controlling the conduction of the bidirectional thyristor of the faulty phase leg, the standby bridge arm can be used to replace the faulty phase leg, enabling timely repair of the faulty phase leg and ensuring the safe and stable operation of the energy storage converter.

[0143] In an exemplary embodiment, taking the energy storage converter as an energy storage converter and the power unit as a SiC MOSFET power unit as an example, the fault detection system of the energy storage converter includes an energy storage converter and a power grid. Among them, the energy storage converter includes multiple power units. On this basis, as Figure 10 shown, the fault detection method of the energy storage converter includes:

[0144] Step S1: Obtain an accurate behavioral description of the SiC MOSFET power unit without approximation from the perspective of the hybrid system, and construct a hybrid model of the energy storage converter system based on hybrid logic dynamics;

[0145] Step S2: Based on the hybrid logic dynamic model of the energy storage converter system, use the system state residuals constructed in the three - phase stationary coordinate system to diagnose the faults of the SiC MOSFET power units;

[0146] Step S3: Obtain the system state residuals of the energy storage converter system, establish a state residual vector, and determine the faulty SiC MOSFET power unit according to the residual vector for fault location;

[0147] Step S4: Perform a fault - tolerant control strategy according to the fault location result to improve the voltage output ability of the energy storage converter after the fault and ensure the smooth operation of the system.

[0148] In step S1, first, a voltage continuous model of the energy storage converter is constructed. The voltage continuous model consists of the resistance parameter and inductance parameter of the energy storage converter, the three-phase voltage parameters and three-phase current parameters of the converter output by the energy storage converter, and the three-phase voltage parameters of the power grid. The voltage continuous model is used to characterize the three-phase voltage of the converter output by the energy storage converter when the energy storage converter is connected to the power grid. Then, the power unit voltage parameter of the power unit is used to correct the three-phase voltage parameter of the converter in the voltage continuous model to generate a hybrid logical dynamic model of the energy storage converter.

[0149] In step S2, the resistance value and inductance value information of the energy storage converter, the three-phase voltage value of the converter output by the energy storage converter, the three-phase voltage value of the power grid to which the energy storage converter is connected, and the output voltage value of each power unit are obtained to get the power unit voltage value. These information values are used as the input of the hybrid logical dynamic model to generate the theoretical inductor current of the energy storage converter, and the local current residual value of each phase bridge arm of the energy storage converter is generated according to the theoretical inductor current and the converter inductor current.

[0150] In step S3, when the local current residual values of all phase bridge arms are 0, there is no faulty power unit in the energy storage converter. When the current residual value of a certain phase bridge arm is equal to the current residual values of the other two phase bridge arms and has the opposite sign, there is a faulty power unit in the energy storage converter, and the phase bridge arm with the current residual value equal to the current residual values of the other two phase bridge arms is the target phase bridge arm with the faulty power unit.

[0151] Furthermore, the target power unit with a fault can be located from the target phase bridge arm according to the amplitude information and phase information of the local current residual information of the target phase bridge arm. For example, when the amplitude information and phase information indicate that the local current residual information moves along the negative half cycle, it is located that the power unit of the upper bridge arm of the target phase bridge arm has an open circuit fault; when the amplitude information and phase information indicate that the local current residual information moves along the positive half cycle, it is located that the power unit of the lower bridge arm of the target phase bridge arm has an open circuit fault.

[0152] In addition, the mapping relationship between the current residual information and the fault location result of the three-phase bridge arms in the energy storage converter can be preset in advance. Based on the current residual corresponding to each power unit of each phase bridge arm, a current residual vector of the energy storage converter is generated, and the amplitude information and phase information of the current residual vector are obtained. According to the mapping relationship, the amplitude information and phase information of the current residual vector, the power units of the three-phase bridge arms are fault-detected, and the fault detection results of the power units of the three-phase bridge arms are directly obtained.

[0153] Among them, when the amplitude information and phase information indicate that the current residual vector is located at the origin, a fault detection result of the power unit of the three-phase bridge arm is generated, and the fault detection result indicates that there is no fault in the power unit of the three-phase bridge arm; when the amplitude information and phase information indicate that the current residual vector moves along the axis matching the upper arm of the target phase bridge arm, an open-circuit fault occurs in the power unit of the upper arm of the target phase bridge arm, and when the amplitude information and phase information indicate that the current residual vector moves along the axis matching the lower arm of the target phase bridge arm, an open-circuit fault occurs in the power unit of the lower arm of the target phase bridge arm.

[0154] In step S4, when the fault detection result indicates that there is an open-circuit fault in the power unit of the target phase bridge arm, the bidirectional thyristor of the target phase bridge arm is controlled to conduct, where the bidirectional thyristor after conduction is used to replace the faulty target phase bridge arm with the standby phase bridge arm and connect it to the working circuit of the energy storage converter.

[0155] Based on the above analysis, by establishing and solving the hybrid logic dynamic model of the SiC MOSFET power unit, establishing and solving the current residual equation and current residual space vector equation of the power unit, obtaining the current residual values of each power unit, and accordingly judging whether the power unit has a fault, so as to perform fault location and fault tolerance control of the power unit, ensuring that the system can operate normally under fault conditions, which is beneficial to improving the robustness of the energy storage converter system.

[0156] It should be understood that although the steps in the flowcharts involved in the above embodiments are shown in sequence according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless there is a clear description in this article, the execution of these steps has no strict order limit, and these steps can be executed in other orders. Moreover, at least a part of the steps in the flowcharts involved in the above embodiments may include multiple steps or multiple stages, and these steps or stages are not necessarily executed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily sequential, but can be executed alternately or alternately with at least a part of other steps or steps or stages in other steps.

[0157] Based on the same inventive concept, the embodiment of the present application also provides a fault detection device for an energy storage converter for implementing the above-mentioned fault detection method of the energy storage converter. The solution provided by this device to solve the problem is similar to the solution recorded in the above method. Therefore, the specific limitations in one or more embodiments of the following fault detection devices for energy storage converters can refer to the limitations on the fault detection method of the energy storage converter in the above text, and will not be repeated here.

[0158] In an exemplary embodiment, as Figure 11As shown, a fault detection device for an energy storage converter is provided, including: a first data acquisition module 100, a second data acquisition module 200, a current prediction module 300, an actual current acquisition module 400, and a fault detection module 500, where:

[0159] The first data acquisition module 100 is configured to determine the resistance information and inductance information of the energy storage converter, the three-phase converter voltage information output by the energy storage converter, and the three-phase grid voltage information of the grid to which the energy storage converter is connected. The energy storage converter includes a plurality of power units.

[0160] The second data acquisition module 200 is configured to detect the output voltage of each power unit to obtain power unit voltage information.

[0161] The current prediction module 300 is configured to respectively predict the theoretical inductive current information output by each power unit according to the resistance information and inductance information, the three-phase converter voltage information, the three-phase grid voltage information, and the power unit voltage information.

[0162] The actual current acquisition module 400 is configured to obtain the actual inductive current information output by each power unit.

[0163] The fault detection module 500 is configured to respectively perform fault detection on a plurality of power units in the energy storage converter according to the difference between the theoretical inductive current information and the actual inductive current information of all power units to obtain a fault detection result.

[0164] In one embodiment, the fault detection device for the energy storage converter further includes a model construction model. The model construction module is configured to obtain a pre-constructed voltage continuous model of the energy storage converter. The voltage continuous model is composed of the resistance parameters and inductance parameters of the energy storage converter, the three-phase converter voltage parameters and three-phase converter current parameters output by the energy storage converter, and the three-phase grid voltage parameters of the grid. The voltage continuous model is used to characterize the three-phase converter voltage output by the energy storage converter when the energy storage converter is connected to the grid; use the power unit voltage parameters of the power unit to correct the three-phase converter voltage parameters in the voltage continuous model to generate a hybrid logical dynamic model of the energy storage converter; the current prediction module 400 is further configured to use the resistance information and inductance information, the three-phase converter voltage information, the three-phase grid voltage information, and the power unit voltage information as model inputs, and use the hybrid logical dynamic model to predict the theoretical inductive current of the energy storage converter.

[0165] In one embodiment, the energy storage converter includes three-phase bridge arms. The fault detection module 500 is further configured to generate local current residual information corresponding to each phase bridge arm in the three-phase bridge arms according to the difference between the theoretical inductor current information and the actual inductor current information of all power units; detect whether a power unit in the energy storage converter fails according to the correlation relationship between the local current residual information corresponding to each phase bridge arm; in the case of detecting that a power unit in the energy storage converter fails, locate the target phase bridge arm with a faulty power unit from each phase bridge arm according to the local current residual information corresponding to each phase bridge arm; generate current residual information of the energy storage converter according to the local current residual information corresponding to each phase bridge arm, and locate the target power unit with a fault from the target phase bridge arm according to the current residual information.

[0166] In one embodiment, the fault detection module 500 is further configured to determine the local current residual information corresponding to each phase bridge arm in the three-phase bridge arms from the current residual information; detect whether a power unit in the energy storage converter fails according to the correlation relationship between the local current residual information corresponding to each phase bridge arm; in the case of detecting that a power unit in the energy storage converter fails, locate the target phase bridge arm with a faulty power unit from each phase bridge arm according to the local current residual information corresponding to each phase bridge arm; locate the target power unit with a fault from the target phase bridge arm according to the local current residual information of the target phase bridge arm.

[0167] In one embodiment, the current residual information includes a current residual vector. The fault detection module 500 is further configured to determine the amplitude information and phase information of the current residual vector; locate the target power unit with a fault from the target phase bridge arm according to the amplitude information and phase information.

[0168] In one embodiment, the fault detection module 500 is further configured to obtain the mapping relationship between the preset amplitude information and phase information of the current residual vector and the fault location results of multiple power units in the energy storage converter; detect the fault detection results of multiple power units in the energy storage converter that match the amplitude information and phase information according to the mapping relationship.

[0169] In one embodiment, the fault detection device of the energy storage converter further includes a fault repair module. The fault repair module is configured to control the bidirectional thyristor of the target phase bridge arm to conduct when the fault detection result indicates that there is an open circuit fault in the power unit of the target phase bridge arm. After conduction, the bidirectional thyristor is used to replace the faulty target phase bridge arm with a standby phase bridge arm and connect it to the working circuit of the energy storage converter.

[0170] Each module in the above-mentioned fault detection device of the energy storage converter can be implemented in whole or in part by software, hardware, or a combination thereof. Each of the above modules can be embedded in or independent of the processor in the computer device in the form of hardware, or stored in the memory of the computer device in the form of software, so that the processor can call and execute the operations corresponding to each of the above modules.

[0171] In an exemplary embodiment, a computer device is provided. The computer device can be a server, and its internal structural diagram can be as Figure 12 shown. The computer device includes a processor, a memory, an input / output interface (Input / Output, abbreviated as I / O), and a communication interface. Among them, the processor, the memory, and the input / output interface are connected through a system bus, and the communication interface is connected to the system bus through the input / output interface. Among them, the processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system, a computer program, and a database. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The database of the computer device is used to store data such as the resistance information and inductance information of the energy storage converter, the three-phase voltage information of the converter output by the energy storage converter, and the three-phase voltage information of the power grid to which the energy storage converter is connected. The input / output interface of the computer device is used to exchange information between the processor and external devices. The communication interface of the computer device is used to communicate with an external terminal through a network connection. When the computer program is executed by the processor, it implements a fault detection method for an energy storage converter.

[0172] Those skilled in the art can understand that Figure 12 the structure shown in

[0173] is a block diagram of a part of the structure related to the solution of this application, and does not constitute a limitation on the computer device to which the solution of this application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different component layout.

[0174] In an embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, it implements the steps in the above-mentioned method embodiments.

[0175] In one embodiment, a computer program product is provided, including a computer program which, when executed by a processor, implements the steps in the above method embodiments.

[0176] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data for analysis, stored data, displayed data, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use, and processing of relevant data need to comply with relevant regulations.

[0177] Those of ordinary skill in the art can understand that all or part of the processes in the above method embodiments can be completed by instructing relevant hardware through a computer program. The computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the above method embodiments. Among them, any reference to a memory, database, or other medium used in the embodiments provided in this application can include at least one of non-volatile memory and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetoresistive random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM), etc. The databases involved in the embodiments provided in this application can include at least one of relational databases and non-relational databases. Non-relational databases can include distributed databases based on blockchain, etc., and are not limited thereto. The processors involved in the embodiments provided in this application can be general-purpose processors, central processors, graphics processors, digital signal processors, programmable logic devices, data processing logics based on quantum computing, artificial intelligence (AI) processors, etc., and are not limited thereto.

[0178] The technical features of the above embodiments can be combined arbitrarily. For the sake of concise description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope recorded in this application.

[0179] The above embodiments only represent several implementation manners of this application, and their descriptions are relatively specific and detailed. However, it should not be construed as a limitation to the patent scope of this application. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several modifications and improvements can still be made, and these all belong to the protection scope of this application. Therefore, the protection scope of this application should be subject to the appended claims.

Claims

1. A fault detection method for an energy storage converter, characterized in that: The method comprises: Determine the resistance information and inductance information of the energy storage converter, the converter three-phase voltage information output by the energy storage converter, and the grid three-phase voltage information of the grid to which the energy storage converter is connected, wherein the energy storage converter includes a plurality of power units; Detecting the output voltage of each of the power units to obtain power unit voltage information; According to the resistance information and the inductance information, the three-phase voltage information of the converter, the three-phase voltage information of the power grid and the voltage information of the power unit, respectively predict the theoretical inductance current information output by each of the power units; Acquiring actual inductor current information output by each of the power units; According to the difference between the theoretical inductor current information and the actual inductor current information of all the power units, fault detection is performed on multiple power units in the energy storage converter respectively to obtain a fault detection result.

2. The method according to claim 1, characterized in that Before predicting the theoretical inductor current information output by each power unit according to the resistance information and the inductance information, the converter three-phase voltage information, the grid three-phase voltage information and the power unit voltage information, the method further includes: Obtain a pre-built voltage continuity model of the energy storage converter, wherein the voltage continuity model is composed of resistance parameters and inductance parameters of the energy storage converter, converter three-phase voltage parameters and converter three-phase current parameters output by the energy storage converter, and grid three-phase voltage parameters of the grid, and the voltage continuity model is used to characterize the converter three-phase voltage output by the energy storage converter when the energy storage converter is connected to the grid; Using the power unit voltage parameters of the power unit, the three-phase voltage parameters of the converter in the voltage continuity model are corrected to generate a hybrid logic dynamic model of the energy storage converter; The method of predicting theoretical inductor current information output by each power unit according to the resistance information and the inductance information, the three-phase voltage information of the converter, the three-phase voltage information of the power grid and the voltage information of the power unit, further includes: The resistance information and inductance information, the converter three-phase voltage information, the grid three-phase voltage information and the power unit voltage information are used as model inputs, and the hybrid logic dynamic model is used to predict the theoretical inductance current of the energy storage converter.

3. The method according to claim 1, characterized in that The energy storage converter includes a three-phase bridge arm; the fault detection is performed on multiple power units in the energy storage converter according to the difference between the theoretical inductor current information and the actual inductor current information of all the power units, including: Generate local current residual information corresponding to each phase bridge arm in the three-phase bridge arm according to the difference between the theoretical inductor current information and the actual inductor current information of all the power units; Detecting whether a power unit in the energy storage converter fails according to the correlation relationship between the local current residual information corresponding to each of the phase bridge arms; When a power unit in the energy storage converter is detected to have a fault, locating a target phase bridge arm where the faulty power unit is located from each of the phase bridge arms according to the local current residual information corresponding to each of the phase bridge arms; According to the local current residual information corresponding to each of the phase bridge arms, the current residual information of the energy storage converter is generated, and according to the current residual information, the target power unit with a fault is located from the target phase bridge arm.

4. The method according to claim 3, characterized in that The detecting whether a power unit in the energy storage converter fails according to the correlation between the local current residual information corresponding to each phase bridge arm includes: According to the local current residual information corresponding to each of the phase bridge arms, a local current residual value corresponding to each of the phase bridge arms is obtained; When the sum of the local current residual values ​​corresponding to all the phase bridge arms is a preset value, it is detected that no fault occurs in the power unit in the energy storage converter; When the sum of the local current residual values ​​corresponding to all the phase bridge arms is not a preset value, and there is a local current residual value corresponding to any target phase bridge arm in the three-phase bridge arms that is consistent with the sum of the local current residual values ​​corresponding to two phase bridge arms other than the target phase bridge arm and has an opposite sign, it is detected that the power unit of the target phase bridge arm has a fault.

5. The method according to claim 3, characterized in that: The current residual information includes a current residual vector, and locating a target power unit with a fault from the target phase bridge arm according to the current residual information includes: Determining amplitude information and phase information of the current residual vector; A target power unit with a fault is located from the target phase bridge arm according to the amplitude information and the phase information.

6. The method according to claim 5, characterized in that The method of locating a target power unit having a fault from the target phase bridge arm according to the amplitude information and the phase information of the current residual vector comprises: Acquire a mapping relationship between the amplitude information and phase information of a preset current residual vector and the fault location results of multiple power units in the energy storage converter; According to the mapping relationship, fault detection results of multiple power units in the energy storage converter that match the amplitude information and the phase information are detected.

7. The method according to any one of claims 1 to 6, characterized in that: The method further comprises: When the fault detection result indicates that an open circuit fault occurs in the power unit of the target phase bridge arm, the bidirectional thyristor of the target phase bridge arm is controlled to be turned on, wherein the turned-on bidirectional thyristor is used to replace the faulty target phase bridge arm with a spare phase bridge arm and connect it to the working circuit of the energy storage converter.

8. A fault detection device for an energy storage converter, characterized in that: The device comprises: A first data acquisition module is used to determine the resistance information and inductance information of the energy storage converter, the converter three-phase voltage information output by the energy storage converter, and the grid three-phase voltage information of the grid to which the energy storage converter is connected, wherein the energy storage converter includes a plurality of power units; A second data acquisition module is used to detect the output voltage of each power unit to obtain power unit voltage information; A current prediction module, used to predict theoretical inductance current information output by each power unit according to the resistance information and inductance information, the three-phase voltage information of the converter, the three-phase voltage information of the power grid and the power unit voltage information; An actual current acquisition module, used to acquire actual inductor current information output by each of the power units; The fault detection module is used to perform fault detection on multiple power units in the energy storage converter according to the difference between the theoretical inductor current information and the actual inductor current information of all the power units to obtain a fault detection result.

9. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 7 are implemented.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 7 are implemented.

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