Energy storage converter and bus capacitor capacitance value calculation method, device and equipment thereof

Abstract

The invention relates to an energy storage converter and a bus capacitor capacitance value calculation method, device and equipment thereof. The method comprises the following steps: acquiring an energy storage element voltage, n bus capacitor voltages and n charging currents of the energy storage converter; calculating a time constant according to the energy storage element voltage and the bus capacitor voltage; calculating charging resistance according to the voltage of the energy storage element, the charging current and the time constant; according to all the time constants and all the charging resistances, a time constant mean value and a charging resistance mean value are obtained through calculation; and calculating the capacitance value of a bus capacitor in the energy storage converter according to the time constant mean value and the charging resistance mean value. The method comprises the following steps: obtaining an energy storage element voltage, n bus capacitor voltages and n charging currents of an energy storage converter, and calculating to obtain a time constant mean value and a charging resistance mean value; the capacitance value of the bus capacitor in the energy storage converter is obtained according to calculation, calculation of the capacitance value of the direct current capacitor in the energy storage converter is achieved, and the method is simple and low in cost.

Description

Technical Field

[0001] The present application relates to the technical field of energy storage converters, and particularly to an energy storage converter, a method, a device, and equipment for calculating the capacitance value of a bus capacitor thereof. Background Art

[0002] In an electrochemical energy storage system, an energy storage converter realizes bidirectional power conversion between a battery and an AC power grid. The aging and performance degradation of the energy storage converter will directly affect the overall charge and discharge performance and reliability of the electrochemical energy storage system. Among all the electrical components inside the energy storage converter, the DC bus capacitor ages the fastest and has the shortest lifespan, which is the weak point of the entire energy storage converter. Therefore, on-line monitoring and fault warning of the DC bus capacitor are particularly important.

[0003] The aging of the DC bus capacitor is mainly manifested as a decrease in capacitance value, an increase in equivalent series resistance (ESR), an increase in leakage current, etc. Among them, the decrease in capacitance value is the most common and obvious. Therefore, most of the fault warnings for the bus capacitor are based on the detection of the capacitance value of the capacitor. The detection methods for the capacitance value of the bus capacitor are divided into off-line detection and on-line detection. Off-line detection is to directly measure the capacitance value using an LCR meter or a capacitance tester and compare it with the nominal value. The on-line detection method is to indirectly estimate the capacitance value by outputting an AC signal or combining circuit characteristics.

[0004] Existing off-line capacitance detection methods require removing the DC capacitor from the original circuit and then connecting a special instrument to measure the capacitance value. This off-line capacitance detection method is complex to operate, and when the capacitance value of the capacitor is detected, the energy storage converter cannot operate normally. Existing on-line capacitance detection methods require additional current and voltage sensors, which will increase the cost of the hardware circuit and increase the complexity of the hardware circuit. Other on-line capacitance detection methods, although they do not require additional current and voltage sensors, but the algorithms for capacitance estimation are very complex, which puts high requirements on the computing power of the main control chip of the energy storage converter, and this also indirectly increases the hardware cost. Summary of the Invention

[0005] The present application provides an energy storage converter, a method, a device, and equipment for calculating the capacitance value of a bus capacitor thereof, which are used to solve the technical problems that the off-line detection of the DC bus capacitor of the existing energy storage converter is complex to operate, the energy storage converter needs to stop running, and the on-line detection methods of its DC bus capacitor all need to increase the hardware cost.

[0006] To achieve the above object, the present application provides the following technical solutions:

[0007] On the one hand, a method for calculating the capacitance value of a bus capacitor of an energy storage converter is provided, including the following steps:

[0008] Obtain the voltage of the energy storage element of the energy storage converter, and obtain the n bus capacitor voltages and n charging currents during the charging process of the bus capacitor of the energy storage converter;

[0009] Calculate according to the energy storage element voltage and the bus capacitor voltage to obtain the time constant corresponding to each bus capacitor voltage; calculate according to the energy storage element voltage, the charging current and the time constant corresponding to the charging current to obtain the charging resistance corresponding to the charging current;

[0010] Calculate respectively according to all the time constants and all the charging resistances to obtain the corresponding average time constant and average charging resistance;

[0011] Calculate according to the average time constant and the average charging resistance to obtain the capacitance value of the bus capacitor in the energy storage converter.

[0012] Preferably, the method for calculating the capacitance value of the bus capacitor of the energy storage converter includes: calculating according to the energy storage element voltage and the bus capacitor voltage using the time constant formula to obtain the time constant corresponding to each bus capacitor voltage; the time constant formula is:

[0013]

[0014] In the formula, T i is the i-th sampling time point, t i is the sampling time of the i-th sampling time point, U B is the voltage of the energy storage element, U C (T i )is the bus capacitor voltage at the i-th sampling time point, τ(T i )is the time constant at the i-th sampling time point.

[0015] Preferably, the method for calculating the capacitance value of the bus capacitor of the energy storage converter includes: calculating according to the energy storage element voltage, the charging current and the time constant corresponding to the charging current using the resistance formula to obtain the charging resistance corresponding to the charging current; the resistance formula is:

[0016]

[0017] In the formula, T i is the i-th sampling time point, t i is the sampling time of the i-th sampling time point, U B is the voltage of the energy storage element, i dc (T i )is the charging current at the i-th sampling time point, τ(T i )is the time constant at the i-th sampling time point, R(T iis the charging resistance at the i-th sampling time point.

[0018] Preferably, the method for calculating the capacitance value of the bus capacitor of the energy storage converter includes: performing a division calculation based on the average value of the time constant and the average value of the charging resistance to obtain the capacitance value of the bus capacitor in the energy storage converter.

[0019] In a second aspect, an energy storage converter is provided, including an energy storage element, a soft start module, a DC capacitor, an AC / DC conversion module, and an output module. The first end of the energy storage element is connected to the first end of the DC capacitor and the AC / DC conversion module respectively through the soft start module. The second end of the energy storage element is connected to the second end of the DC capacitor and the AC / DC conversion module respectively. The AC / DC conversion module is connected to the output module, and the capacitance value of the DC capacitor is obtained by using the method for calculating the capacitance value of the bus capacitor of the energy storage converter described above.

[0020] Preferably, the soft start module includes a soft start resistor, a soft start contactor, and a main contactor. The soft start contactor is connected in series with the soft start resistor and then connected in parallel with the main contactor.

[0021] In a third aspect, a device for calculating the capacitance value of the bus capacitor of an energy storage converter is provided, including a data acquisition module, a first calculation module, a second calculation module, and a third calculation module;

[0022] The data acquisition module is configured to acquire the voltage of the energy storage element of the energy storage converter and acquire n bus capacitor voltages and n charging currents during the charging process of the bus capacitor of the energy storage converter;

[0023] The first calculation module is configured to calculate, based on the voltage of the energy storage element and the voltage of the bus capacitor, to obtain the time constant corresponding to each bus capacitor voltage; calculate, based on the voltage of the energy storage element, the charging current, and the time constant corresponding to the charging current, to obtain the charging resistance corresponding to the charging current;

[0024] The second calculation module is configured to calculate, respectively based on all the time constants and all the charging resistances, to obtain the corresponding average value of the time constant and the average value of the charging resistance;

[0025] The third calculation module is configured to calculate, based on the average value of the time constant and the average value of the charging resistance, to obtain the capacitance value of the bus capacitor in the energy storage converter.

[0026] Preferably, the first calculation module is further configured to calculate, based on the voltage of the energy storage element and the voltage of the bus capacitor, by using the time constant formula, to obtain the time constant corresponding to each bus capacitor voltage; the time constant formula is:

[0027]

[0028] Wherein, T i is the i-th sampling time point, t i is the sampling time at the i-th sampling time point, U B is the voltage of the energy storage element, U C (T i ) is the bus capacitor voltage at the i-th sampling time point, τ(T i ) is the time constant at the i-th sampling time point.

[0029] Preferably, the first calculation module is further configured to calculate, according to the voltage of the energy storage element, the charging current, and the time constant corresponding to the charging current, by using a resistance formula, to obtain a charging resistance corresponding to the charging current; the resistance formula is:

[0030]

[0031] Wherein, T i is the i-th sampling time point, t i is the sampling time at the i-th sampling time point, U B is the voltage of the energy storage element, i dc (T i ) is the charging current at the i-th sampling time point, τ(T i ) is the time constant at the i-th sampling time point, R(T i ) is the charging resistance at the i-th sampling time point.

[0032] On the other hand, a terminal device is provided, including a processor and a memory;

[0033] The memory is configured to store program codes and transmit the program codes to the processor;

[0034] The processor is configured to execute the method for calculating the capacitance value of the bus capacitor of the energy storage converter as described above according to the instructions in the program codes.

[0035] The energy storage converter and its method, device and equipment for calculating the capacitance value of the bus capacitor. The method for calculating the capacitance value of the bus capacitor of the energy storage converter includes obtaining the voltage of the energy storage element of the energy storage converter, and obtaining n bus capacitor voltages and n charging currents during the charging process of the bus capacitor of the energy storage converter; calculating according to the voltage of the energy storage element and the bus capacitor voltage to obtain the time constant corresponding to each bus capacitor voltage; calculating according to the voltage of the energy storage element, the charging current and the time constant corresponding to the charging current to obtain the charging resistance corresponding to the charging current; calculating according to all the time constants and all the charging resistances respectively to obtain the corresponding average time constant and average charging resistance; calculating according to the average time constant and the average charging resistance to obtain the capacitance value of the bus capacitor in the energy storage converter.

[0036] As can be seen from the above technical solutions, the present application has the following advantages: The method for calculating the capacitance value of the bus capacitor of the energy storage converter calculates the average time constant and the average charging resistance by obtaining the voltage of the energy storage element of the energy storage converter and n bus capacitor voltages and n charging currents during the charging process of the bus capacitor; then calculates the capacitance value of the bus capacitor in the energy storage converter according to the average time constant and the average charging resistance, realizing the calculation of the capacitance value of the DC capacitor in the energy storage converter. This method is simple and low-cost, and there is no need to stop the operation of the energy storage converter, solving the technical problems that the off-line detection operation of the DC bus capacitor of the existing energy storage converter is complicated, the energy storage converter needs to stop running, and the on-line detection methods of its DC bus capacitor all need to increase the hardware cost.

[0037] The energy storage converter realizes the detection of the capacitance value of the bus capacitor through the method for calculating the capacitance value of the bus capacitor of the energy storage converter. The energy storage converter does not need to stop the machine, nor does it need to remove the capacitor and connect it to a special instrument for measurement; the energy storage converter also does not need to add any electrical components, nor does it need to change the existing circuit, so it will not increase any hardware cost. The energy storage converter can realize the detection of the capacitance value during the startup process of the energy storage converter. If it is found that the capacitance value decays severely, the startup process can be interrupted, thus avoiding serious faults such as leakage and fire of the bus capacitor.

[0038] The device for calculating the capacitance value of the bus capacitor of the energy storage converter realizes the calculation of the capacitance value of the bus capacitor in the energy storage converter through a data acquisition module, a first calculation module, a second calculation module and a third calculation module. Description of the Drawings

[0039] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0040] Figure 1 It is a flowchart of the steps of the method for calculating the capacitance value of the bus capacitor of the energy storage converter described in the embodiments of the present application;

[0041] Figure 2 It is a waveform diagram of the charging voltage of the bus capacitor in the method for calculating the capacitance value of the bus capacitor of the energy storage converter described in the embodiments of the present application;

[0042] Figure 3 It is a waveform diagram of the charging current of the bus capacitor in the method for calculating the capacitance value of the bus capacitor of the energy storage converter described in the embodiments of the present application;

[0043] Figure 4 It is a schematic topology diagram of the energy storage converter described in the embodiments of the present application;

[0044] Figure 5 It is a schematic framework diagram of the device for calculating the capacitance value of the bus capacitor of the energy storage converter described in the embodiments of the present application;

[0045] Figure 6 It is a schematic diagram of the terminal device described in the embodiments of the present application. Detailed implementation manners

[0046] To make the objectives, features, and advantages of the present application more obvious and understandable, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the embodiments described below are only a part of the embodiments of the present application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0047] In the description of the embodiments of the present application, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. In the description of the embodiments of the present application, "a plurality" means two or more unless otherwise specifically defined.

[0048] In the embodiments of the present application, unless otherwise clearly defined and limited, the terms "installed", "connected", "connected", "fixed", etc. shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the internal connection of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present application can be understood according to specific situations.

[0049] The embodiments of the present application provide an energy storage converter and a method, device and equipment for calculating the capacitance value of its bus capacitor, which solve the technical problems that the off-line detection of the DC bus capacitor of the existing energy storage converter is complicated in operation, the energy storage converter needs to stop running, and the on-line detection methods of its DC bus capacitor all require an increase in hardware cost.

[0050] Embodiment 1:

[0051] Figure 1 It is a step flow chart of the method for calculating the capacitance value of the bus capacitor of the energy storage converter described in the embodiments of the present application.

[0052] As Figure 1 shown, the embodiments of the present application provide a method for calculating the capacitance value of the bus capacitor of an energy storage converter, including the following steps:

[0053] S1. Obtain the voltage of the energy storage element of the energy storage converter, and obtain n bus capacitor voltages and n charging currents during the charging process of the bus capacitor of the energy storage converter.

[0054] It should be noted that obtaining the voltage of the energy storage element of the energy storage converter and the bus capacitor voltage and charging current corresponding to n sampling time points during the charging process of the bus capacitor in step S1 provides data for calculating the capacitance value of the bus capacitor in the energy storage converter in the subsequent steps. In this embodiment, during the charging process of the bus capacitor when the energy storage converter starts, the bus capacitor voltage and charging current corresponding to n sampling time points are obtained. After the voltage of the bus capacitor reaches the charging threshold value, the voltage of the bus capacitor at this time is obtained as the voltage of the energy storage element. Among them, let the sampling time points be T1, T2,..., T n . n is the total number of sampling points. The sampled bus capacitor voltages are U c (T1), U c (T2),..., U c (T n ). The sampled charging currents are I dc (T1), I dc (T2),..., I dc (T n ).

[0055] Figure 2 It is the charging voltage waveform diagram of the bus capacitor in the method for calculating the capacitance value of the bus capacitor of the energy storage converter described in the embodiments of the present application, Figure 3 It is the charging current waveform diagram of the bus capacitor in the method for calculating the capacitance value of the bus capacitor of the energy storage converter described in the embodiments of the present application.

[0056] As Figure 2 and Figure 3As shown in the figure, in the embodiment of the present application, the method for calculating the capacitance value of the bus capacitor of the energy storage converter can obtain the corresponding n bus capacitor voltages and n charging currents by obtaining the charging voltage waveform diagram and the charging current waveform diagram during the charging process of the bus capacitor in the energy storage converter respectively.

[0057] S2. Calculate according to the energy storage element voltage and the bus capacitor voltage to obtain the time constant corresponding to each bus capacitor voltage; calculate according to the energy storage element voltage, the charging current and the time constant corresponding to the charging current to obtain the charging resistance corresponding to the charging current.

[0058] It should be noted that in step S2, according to the energy storage element voltage obtained in step S1, the bus capacitor voltage and the charging current at each sampling time point, the time constant and the charging resistance corresponding to each sampling time point are calculated respectively, providing data for calculating the capacitance value of the bus capacitor in the energy storage converter in the subsequent steps.

[0059] S3. Calculate respectively according to all the time constants and all the charging resistances to obtain the corresponding average time constant and average charging resistance.

[0060] It should be noted that in step S3, the average time constant is obtained by calculating the average value of the n time constants obtained in step S2; and the average charging resistance is obtained by calculating the average value of the n charging resistances obtained in step S2, so as to reduce the calculation error of the capacitance value of the bus capacitor and improve the accuracy of the calculation result.

[0061] S4. Calculate according to the average time constant and the average charging resistance to obtain the capacitance value of the bus capacitor in the energy storage converter.

[0062] It should be noted that in step S4, according to the average time constant τ avg and the average charging resistance R avg obtained in step S3, perform division calculation to obtain the capacitance value C of the bus capacitor in the energy storage converter; it can be understood that: C = τ avg / R avg .

[0063] In the embodiment of the present application, the method for calculating the capacitance value of the bus capacitor of the energy storage converter calculates by obtaining the energy storage element voltage of the energy storage converter and the n bus capacitor voltages and n charging currents during the charging process of the bus capacitor, to obtain the average time constant and the average charging resistance; then calculate the capacitance value of the bus capacitor in the energy storage converter according to the average time constant and the average charging resistance.

[0064] A method for calculating the capacitance value of the bus capacitor of an energy storage converter provided by this application includes obtaining the voltage of the energy storage element of the energy storage converter and obtaining n bus capacitor voltages and n charging currents during the charging process of the bus capacitor of the energy storage converter; calculating according to the voltage of the energy storage element and the voltage of the bus capacitor to obtain the time constant corresponding to each bus capacitor voltage; calculating according to the voltage of the energy storage element, the charging current and the time constant corresponding to the charging current to obtain the charging resistance corresponding to the charging current; calculating respectively according to all the time constants and all the charging resistances to obtain the corresponding average time constant and average charging resistance; calculating according to the average time constant and the average charging resistance to obtain the capacitance value of the bus capacitor in the energy storage converter. The method for calculating the capacitance value of the bus capacitor of the energy storage converter calculates by obtaining the voltage of the energy storage element of the energy storage converter and n bus capacitor voltages and n charging currents during the charging process of the bus capacitor, and obtains the average time constant and the average charging resistance; then calculates the capacitance value of the bus capacitor in the energy storage converter according to the average time constant and the average charging resistance, realizing the calculation of the capacitance value of the DC capacitor in the energy storage converter. This method is simple and low-cost, and there is no need for the energy storage converter to stop running, solving the technical problems that the off-line detection operation of the DC bus capacitor of the existing energy storage converter is complicated, the energy storage converter needs to stop running, and the online detection methods of its DC bus capacitor all need to increase the hardware cost.

[0065] In an embodiment of this application, the method for calculating the capacitance value of the bus capacitor of the energy storage converter includes: calculating according to the voltage of the energy storage element and the voltage of the bus capacitor by using the time constant formula to obtain the time constant corresponding to each bus capacitor voltage; the time constant formula is:

[0066]

[0067] In the formula, T i is the i-th sampling time point, t i is the sampling time of the i-th sampling time point, U B is the voltage of the energy storage element, U C (T i )is the bus capacitor voltage at the i-th sampling time point, τ(T i )is the time constant at the i-th sampling time point.

[0068] It should be noted that the time constant τ is calculated by using the measured bus capacitor voltage at a certain time and the corresponding sampling time through the time constant formula. However, due to the measurement error of the capacitor voltage, using only the measurement result of the capacitor voltage value at a certain time to deduce the time constant τ may have a large error. Therefore, first substitute the detection result U C (T i )of each bus capacitor voltage into the time constant formula to calculate the time constant τ(T i), and then calculate the average value of all these calculated time constants to obtain the average time constant τ avg As the calculation result of the final time constant.

[0069] In an embodiment of the present application, the method for calculating the bus capacitance value of the energy storage converter includes: calculating according to the energy storage element voltage, charging current, and the time constant corresponding to the charging current using the resistance formula to obtain the charging resistance corresponding to the charging current; the resistance formula is:

[0070]

[0071] In the formula, T i is the i-th sampling time point, t i is the sampling time of the i-th sampling time point, U B is the energy storage element voltage, i dc (T i ) is the charging current at the i-th sampling time point, τ(T i ) is the time constant at the i-th sampling time point, and R(T i ) is the charging resistance at the i-th sampling time point.

[0072] It should be noted that in order to reduce the calculation error, the charging resistance R(T dc (T i ) can be calculated according to the charging current Idc i i detected each time, and then the average value of all these calculated charging resistances is calculated to obtain the average charging resistance R avg As the calculation result of the final charging resistance.

[0073] Embodiment 2:

[0074] Figure 4 This is the topological schematic diagram of the energy storage converter described in the embodiment of the present application.

[0075] As Figure 4 shown, the embodiment of the present application provides an energy storage converter, including an energy storage element U B , a soft start module, a DC capacitor C, an AC / DC conversion module, and an output module. The first end of the energy storage element U B is connected to the first end of the DC capacitor C and the AC / DC conversion module respectively through the soft start module. The second end of the energy storage element U B is connected to the second end of the DC capacitor C and the AC / DC conversion module respectively. The AC / DC conversion module is connected to the output module, and the capacitance value of the DC capacitor C is obtained by using the above method for calculating the bus capacitance value of the energy storage converter. The soft start module includes a soft start resistor R, a soft start contactor K1, and a main contactor K2. The soft start contactor K1 is connected in series with the soft start resistor R and then connected in parallel with the main contactor K2.

[0076] It should be noted that the content of the calculation method of the bus capacitance value of the energy storage converter has been described in Embodiment 1, and the content of the calculation method of the bus capacitance value of the energy storage converter will not be repeated in this embodiment. The charging resistance calculated in the calculation method of the bus capacitance value of the energy storage converter is the resistance value of the soft start resistance R. The AC / DC conversion module is composed of multiple MOS transistors, and the output module is used to connect to the power grid. In this embodiment, the energy storage converter obtains n bus capacitance voltages and n charging currents during the process of charging the bus capacitance C. First, close the DC side soft start contactor K1, and the energy storage element U B charges the bus capacitance C through the soft start resistance R, and records the capacitance voltage curve and the charging current curve during the charging process, as Figure 2 and Figure 3 shown. Then, after the voltage of the bus capacitance reaches the charging threshold value, close the main contactor K2, and the energy storage element U B is directly connected to the bus capacitance C, and record the voltage of the bus capacitance after the main contactor K2 is closed. This voltage is used as the energy storage element voltage. Among them, the energy storage element U B can be selected as a battery. The charging threshold value can be 0.95 times the energy storage element voltage.

[0077] In the embodiment of the present application, during the soft start charging process of the energy storage converter, the energy storage element U B , the soft start resistance R and the bus capacitance C form a first-order RC circuit to obtain the voltage change curve of the bus capacitance as shown in Figure 2 .

[0078] In the embodiment of the present application, the energy storage converter realizes the detection of the capacitance value of the bus capacitance through the calculation method of the bus capacitance value of the energy storage converter. The energy storage converter does not need to stop, nor does it need to remove the capacitor and connect it to a dedicated instrument for measurement; the energy storage converter also does not need to add any electrical components, nor does it need to modify the existing circuit, so it will not increase any hardware costs. The energy storage converter can realize the detection of the capacitance value during the startup process of the energy storage converter. If it is found that the capacitance value decays severely, the startup process can be interrupted, thus avoiding serious faults such as liquid leakage and fire of the bus capacitance. The calculation method of the bus capacitance value of the energy storage converter has a simple algorithm and is easy to implement, and there is no need to upgrade the existing control chip of the energy storage converter.

[0079] Embodiment 3:

[0080] Figure 5 It is a framework schematic diagram of the bus capacitance value calculation device of the energy storage converter described in the embodiment of the present application.

[0081] As Figure 5As shown in the figure, an embodiment of the present application provides a device for calculating the capacitance value of the bus capacitor of an energy storage converter, including a data acquisition module 10, a first calculation module 20, a second calculation module 30, and a third calculation module 40;

[0082] The data acquisition module 10 is configured to acquire the voltage of the energy storage element of the energy storage converter, and acquire n bus capacitor voltages and n charging currents during the charging process of the bus capacitor of the energy storage converter;

[0083] The first calculation module 20 is configured to calculate, according to the energy storage element voltage and the bus capacitor voltage, to obtain the time constant corresponding to each bus capacitor voltage; calculate, according to the energy storage element voltage, the charging current, and the time constant corresponding to the charging current, to obtain the charging resistance corresponding to the charging current;

[0084] The second calculation module 30 is configured to calculate, according to all the time constants and all the charging resistances respectively, to obtain the corresponding average time constant and average charging resistance;

[0085] The third calculation module 40 is configured to calculate, according to the average time constant and the average charging resistance, to obtain the capacitance value of the bus capacitor in the energy storage converter.

[0086] It should be noted that the content of the modules in the device of Embodiment 3 has been described in the steps of the method of Embodiment 1, and the content of the modules of the device for calculating the capacitance value of the bus capacitor of the energy storage converter will not be repeated in this embodiment. In this embodiment, the device for calculating the capacitance value of the bus capacitor of the energy storage converter realizes the calculation of the capacitance value of the bus capacitor in the energy storage converter through the data acquisition module, the first calculation module, the second calculation module, and the third calculation module.

[0087] In an embodiment of the present application, the first calculation module 20 is further configured to calculate, according to the energy storage element voltage and the bus capacitor voltage using the time constant formula, to obtain the time constant corresponding to each bus capacitor voltage; the time constant formula is:

[0088]

[0089] In the formula, T i is the i-th sampling time point, t i is the sampling time of the i-th sampling time point, U B is the voltage of the energy storage element, U C (T i )is the bus capacitor voltage at the i-th sampling time point, and τ(T i )is the time constant at the i-th sampling time point.

[0090] In the embodiment of the present application, the first calculation module 20 is further configured to calculate according to the energy storage element voltage, the charging current, and the time constant corresponding to the charging current using the resistance formula to obtain the charging resistance corresponding to the charging current; the resistance formula is:

[0091]

[0092] In the formula, T i is the i-th sampling time point, t i is the sampling time of the i-th sampling time point, U B is the energy storage element voltage, i dc (T i ) is the charging current at the i-th sampling time point, τ(T i ) is the time constant at the i-th sampling time point, and R(T i ) is the charging resistance at the i-th sampling time point.

[0093] Embodiment 4:

[0094] Figure 6 It is a schematic diagram of the terminal device described in the embodiment of the present application.

[0095] As Figure 6 shown, the embodiment of the present application provides a terminal device, including a processor and a memory;

[0096] The memory is used to store program codes and transmit the program codes to the processor;

[0097] The processor is configured to execute the above-mentioned method for calculating the bus capacitor capacitance value of the energy storage converter according to the instructions in the program code.

[0098] It should be noted that the processor is configured to execute the steps in the above-mentioned embodiment of the method for calculating the bus capacitor capacitance value of an energy storage converter according to the instructions in the program code. Alternatively, when the processor executes the computer program, it implements the functions of each module / unit in the above-mentioned system / device embodiments.

[0099] Exemplarily, the computer program can be divided into one or more modules / units. One or more modules / units are stored in the memory and executed by the processor to complete the present application. One or more modules / units can be a series of computer program instruction segments capable of completing specific functions, and the instruction segments are used to describe the execution process of the computer program in the terminal device.

[0100] The terminal device can be a computing device such as a desktop computer, a notebook, a handheld computer, and a cloud server. The terminal device may include, but is not limited to, a processor and a memory. Those skilled in the art can understand that this does not constitute a limitation on the terminal device, and it may include more or fewer components than shown in the figure, or combine certain components, or different components. For example, the terminal device may further include input / output devices, network access devices, a bus, etc.

[0101] The so-called processor may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0102] The memory may be an internal storage unit of the terminal device, such as the hard disk or memory of the terminal device. The memory may also be an external storage device of the terminal device, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc., equipped on the terminal device. Further, the memory may also include both the internal storage unit and the external storage device of the terminal device. The memory is used to store computer programs and other programs and data required by the terminal device. The memory may also be used to temporarily store data that has been output or is to be output.

[0103] Those skilled in the art can clearly understand that for the convenience and brevity of description, the specific working processes of the above-described systems, devices, and units can refer to the corresponding processes in the foregoing method embodiments, and will not be described herein again.

[0104] In several embodiments provided by 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 merely illustrative. For example, the division of the units is only a logical function division. In actual implementation, there can be other division methods. For example, 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 displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces. The indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.

[0105] The units described as separate components may or may not be physically separated. The components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0106] In addition, in each embodiment of the present invention, the functional units can be integrated in a processing unit, or each unit can exist physically alone, or two or more units can be integrated in one unit. The above-mentioned integrated units can be implemented in the form of hardware or in the form of software functional units.

[0107] If the above-mentioned 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 invention, in essence, or the part that contributes to the prior art, or all or part of this technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to enable a computer device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in each embodiment of the present invention. The foregoing storage medium includes: various media such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs that can store program codes.

[0108] As described above, the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them. Although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of each embodiment of the present application.

Claims

1. A method for calculating the capacitance value of the bus capacitor of an energy storage converter, characterized in that, Including the following steps: Obtaining the voltage of the energy storage element of the energy storage converter, and obtaining n bus capacitor voltages and n charging currents during the charging process of the bus capacitor of the energy storage converter; Calculating according to the voltage of the energy storage element and the voltage of the bus capacitor to obtain a time constant corresponding to each bus capacitor voltage; Calculating according to the voltage of the energy storage element, the charging current and the time constant corresponding to the charging current to obtain a charging resistance corresponding to the charging current; Calculating respectively according to all the time constants and all the charging resistances to obtain the corresponding average time constant and average charging resistance; Calculating according to the average time constant and the average charging resistance to obtain the capacitance value of the bus capacitor in the energy storage converter.

2. The method for calculating the bus capacitance value of the energy storage converter according to claim 1, wherein Including: Calculating according to the voltage of the energy storage element and the voltage of the bus capacitor by using the time constant formula to obtain a time constant corresponding to each bus capacitor voltage; The time constant formula is: where T i is the i-th sampling time point, t i is the sampling time at the i-th sampling time point, U B is the energy storage element voltage, U C (T i ) is the bus capacitor voltage at the i-th sampling time point, τ(T i ) is the time constant at the i-th sampling time point.

3. The method for calculating the bus capacitor capacitance value of the energy storage converter according to claim 1, wherein, Including: Calculating according to the voltage of the energy storage element, the charging current and the time constant corresponding to the charging current by using the resistance formula to obtain a charging resistance corresponding to the charging current; The resistance formula is: Where, T i is the i-th sampling time point, t i is the sampling time at the i-th sampling time point, U B is the energy storage element voltage, i dc (T i ) is the charging current at the i-th sampling time point, τ(T i ) is the time constant at the i-th sampling time point, R(T i ) is the charging resistance at the i-th sampling time point.

4. The method for calculating the bus capacitance value of the energy storage converter according to any one of claims 1-3, characterized in that, Including: Performing a division calculation according to the average time constant and the average charging resistance to obtain the capacitance value of the bus capacitor in the energy storage converter.

5. A energy storage converter, characterized in that, Including an energy storage element, a soft start module, a DC capacitor, an AC / DC conversion module and an output module. The first end of the energy storage element is connected to the first end of the DC capacitor and the AC / DC conversion module respectively through the soft start module. The second end of the energy storage element is connected to the second end of the DC capacitor and the AC / DC conversion module respectively. The AC / DC conversion module is connected to the output module. The capacitance value of the DC capacitor is obtained by using the calculation method for the capacitance value of the bus capacitor of the energy storage converter according to any one of claims 1-4.

6. The energy storage converter according to claim 5, characterized in that, The soft start module includes a soft start resistor, a soft start contactor and a main contactor. The soft start contactor is connected in series with the soft start resistor and then connected in parallel with the main contactor.

7. A device for calculating the capacitance value of the bus capacitor of an energy storage converter, characterized in that, Including: A data acquisition module, a first calculation module, a second calculation module and a third calculation module; The data acquisition module is used to obtain the voltage of the energy storage element of the energy storage converter, and obtain n bus capacitor voltages and n charging currents during the charging process of the bus capacitor of the energy storage converter; The first calculation module is used to calculate according to the voltage of the energy storage element and the voltage of the bus capacitor to obtain a time constant corresponding to each bus capacitor voltage; Calculating according to the voltage of the energy storage element, the charging current and the time constant corresponding to the charging current to obtain a charging resistance corresponding to the charging current; The second calculation module is used to calculate respectively according to all the time constants and all the charging resistances to obtain the corresponding average time constant and average charging resistance; The third calculation module is used to calculate according to the average time constant and the average charging resistance to obtain the capacitance value of the bus capacitor in the energy storage converter.

8. The bus capacitor capacitance calculation device of the energy storage converter according to claim 7, characterized in that, The first calculation module is further configured to calculate, according to the energy storage element voltage and the bus capacitor voltage, by using a time constant formula, to obtain a time constant corresponding to each of the bus capacitor voltages; the time constant formula is: Where, T i is the i-th sampling time point, t i is the sampling time at the i-th sampling time point, U B is the energy storage element voltage, U C (T i ) is the bus capacitor voltage at the i-th sampling time point, τ(T i ) is the time constant at the i-th sampling time point.

9. The bus capacitor capacitance calculation device for an energy storage converter according to claim 7, wherein The first calculation module is further configured to calculate, according to the energy storage element voltage, the charging current, and the time constant corresponding to the charging current, by using a resistance formula, to obtain a charging resistance corresponding to the charging current; the resistance formula is: Where, T i is the i-th sampling time point, t i is the sampling time at the i-th sampling time point, U B is the energy storage element voltage, i dc (T i ) is the charging current at the i-th sampling time point, τ(T i ) is the time constant at the i-th sampling time point, R(T i ) is the charging resistance at the i-th sampling time point.

10. A terminal device, characterized in that, including a processor and a memory; The memory is configured to store program code and transmit the program code to the processor; The processor is configured to execute, according to the instructions in the program code, the method for calculating the capacitance value of the bus capacitor of the energy storage converter as described in any one of claims 1-4.

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