Capacitor capacitance online monitoring method, device, system and auxiliary discharge network

Abstract

The application provides a capacitor capacity online monitoring method, device, system and auxiliary discharge network. The method comprises the following steps: when a power converter is in an online running state, collecting a direct current power supply voltage multiple times and recording time points in a stage of bipolar junction transistor disconnection and resistor running; determining capacities of first and second aluminum electrolytic capacitors according to a starting time point of the stage of bipolar junction transistor disconnection and resistor running, a total output current of the first and second aluminum electrolytic capacitors, a resistor value of the resistor, the direct current power supply voltage and the time points; the first and second capacitor branches are connected in parallel with the direct current power supply; the first capacitor branch comprises the resistor and the first aluminum electrolytic capacitor connected in series; the second capacitor branch comprises the second aluminum electrolytic capacitor; and the bipolar junction transistor is connected in parallel with the resistor. The application can realize online monitoring of the capacities of the capacitors and improve the reliability of capacitor state monitoring.

Description

Technical Field

[0001] This application relates to the field of power electronics technology, and in particular to a method, device, system and auxiliary discharge network for online monitoring of capacitor capacitance. Background Technology

[0002] With the increasing maturity of power electronics technology and control strategies, the health status of power converters has gradually become a major concern. As one of the most common components, capacitors play a crucial role in filtering ripple voltage, power decoupling, and energy buffering. However, due to their susceptibility to heat and electrical stress, capacitors have a high degradation rate. Capacitor failures account for up to 30% of power converter failures. Compared to other types of capacitors, aluminum electrolytic capacitors (AECs) have a shorter lifespan. However, due to their advantages of large capacitance and low cost, AECs are generally not replaceable by other types of capacitors. Therefore, monitoring the health status of AECs is crucial for improving converter reliability.

[0003] Currently, common capacitor condition monitoring (CM) solutions are offline, requiring the power converter to be paused and typically necessitating significant manual intervention, making automation impossible. Another common capacitor condition monitoring solution is quasi-online CM, which estimates capacitance using charge-discharge curves under specific conditions (such as startup, shutdown, and no-load). It estimates capacitance by measuring the time constants of capacitance and discharge resistance. While quasi-online CM methods do not require additional current sensors or high sampling frequencies, continuous estimation is not possible during normal operation. Summary of the Invention

[0004] To address at least one problem in the prior art, this application proposes a method, apparatus, system, and auxiliary discharge network for online monitoring of capacitor capacitance, which can monitor the capacitance value of capacitors when the power converter is in online operation, thereby improving the reliability of capacitor condition monitoring.

[0005] To address the aforementioned technical problems, this application provides the following technical solution:

[0006] In a first aspect, this application provides a method for online monitoring of capacitor capacitance, comprising:

[0007] When the power converter is in online operation, during the stage when the bipolar junction transistor is in the off state and the resistor is in operation, the DC power supply voltage is sampled multiple times and the corresponding time points are recorded.

[0008] The starting time of the phase in which the bipolar junction transistor is in the off state and the resistor is in operation, the resistance value of the resistor, and the total output current of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor in the power converter are obtained.

[0009] Based on the starting time point, the total output current, the resistance value, the DC power supply voltage collected each time and their corresponding time points, the capacitance value of the first aluminum electrolytic capacitor and the capacitance value of the second aluminum electrolytic capacitor are monitored and determined.

[0010] The first capacitor branch and the second capacitor branch are connected in parallel with the DC power supply; the first capacitor branch includes the resistor and the first aluminum electrolytic capacitor connected in series; the second capacitor branch includes the second aluminum electrolytic capacitor; and the bipolar junction transistor is connected in parallel with the resistor.

[0011] In one embodiment, the step of repeatedly sampling the DC power supply voltage and recording the corresponding time points during the phase when the bipolar junction transistor is in the off state and the resistor is in operation includes:

[0012] When the power converter is in online operation, during the period when the bipolar junction transistor is in the off state and the resistor is in operation, the DC power supply voltage is collected and recorded at any two time points.

[0013] In one embodiment, the step of monitoring and determining the capacitance values ​​of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor based on the start time point, the total output current, the resistance value, the DC power supply voltage collected at each time, and their respective corresponding time points includes:

[0014] The capacitance value C1 of the first aluminum electrolytic capacitor and the capacitance value C2 of the second aluminum electrolytic capacitor are determined according to the following formula:

[0015]

[0016] Among them, U SM1 (t) represents the DC power supply voltage collected for the first time, ta represents the time point at which the DC power supply voltage was collected for the first time, and U SM2 (t) represents the DC power supply voltage collected for the second time, tb represents the time point at which the DC power supply voltage was collected for the second time, I represents the total output current, R represents the resistance value, and t1 represents the starting time point.

[0017] In one embodiment, during the phase when the bipolar junction transistor is in the off state and the resistor is in operation, the total output current of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor remains constant.

[0018] Secondly, this application provides an online capacitor capacitance monitoring device, comprising:

[0019] The acquisition module is used to acquire the DC power supply voltage multiple times and record the corresponding time points when the power converter is in online operation, during the stage when the bipolar junction transistor is in the off state and the resistor is in operation.

[0020] The acquisition module is used to acquire the starting time point of the stage when the bipolar junction transistor is in the off state and the resistor is in operation, the resistance value of the resistor, and the total output current of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor in the power converter.

[0021] The online monitoring module is used to monitor and determine the capacitance values ​​of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor based on the starting time point, the total output current, the resistance value, the DC power supply voltage collected each time and their corresponding time points.

[0022] The first capacitor branch and the second capacitor branch are connected in parallel with the DC power supply; the first capacitor branch includes the resistor and the first aluminum electrolytic capacitor connected in series; the second capacitor branch includes the second aluminum electrolytic capacitor; and the bipolar junction transistor is connected in parallel with the resistor.

[0023] In one embodiment, the acquisition module includes:

[0024] The acquisition unit is used to acquire and record the DC power supply voltage at any two time points when the power converter is in online operation, during the stage when the bipolar junction transistor is in the off state and the resistor is in operation.

[0025] Thirdly, this application provides an auxiliary discharge network, comprising: a bipolar junction transistor and a resistor; the resistor is connected in series with a first aluminum electrolytic capacitor in a power converter to form a first capacitor branch; the first capacitor branch is connected in parallel with a second capacitor branch, the second capacitor branch comprising: a second aluminum electrolytic capacitor in the power converter; the bipolar junction transistor is connected in parallel with the resistor.

[0026] Fourthly, this application provides an online capacitor capacitance monitoring system, comprising:

[0027] The microcontroller, the auxiliary discharge network, and the online capacitor capacitance monitoring device;

[0028] The microcontroller is used to control the opening and closing of the bipolar junction transistor.

[0029] Fifthly, this application provides an electronic device, including a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor executes the program to implement the online capacitor capacitance monitoring method.

[0030] Sixthly, this application provides a computer-readable storage medium having computer instructions stored thereon, which, when executed by a processor, implement the online capacitor capacitance monitoring method according to any one of claims 1 to 4.

[0031] As can be seen from the above technical solution, this application provides a method, device, system, and auxiliary discharge network for online monitoring of capacitor capacitance. The method includes: when the power converter is in online operation, during the stage where the bipolar junction transistor (BJT) is in the off state and the resistor is in operation, repeatedly acquiring the DC power supply voltage and recording the corresponding time points; obtaining the starting time point of the stage where the BJT is in the off state and the resistor is in operation, the resistance value of the resistor, and the total output current of the first and second aluminum electrolytic capacitors in the power converter; based on the starting time point, the total output current, the resistance value, the acquired DC power supply voltage, and their corresponding time points, monitoring and determining the capacitance value of the first and second aluminum electrolytic capacitors; wherein the first capacitor branch and the second capacitor branch are connected in parallel with the DC power supply; the first capacitor branch includes: a series-connected... The resistor and the first aluminum electrolytic capacitor are described; the second capacitor branch includes: the second aluminum electrolytic capacitor; the bipolar junction transistor (BJT) is connected in parallel with the resistor, which can monitor the capacitance value of the capacitor when the power converter is in online operation, thereby improving the reliability of capacitor status monitoring; specifically, the auxiliary discharge circuit has a simple and reliable structure, and can estimate the capacitance without interrupting the continuous operation of the power converter using a simple and low-cost resistor and a BJT. The estimation process only requires one auxiliary discharge circuit; it does not require a high sampling frequency, but only measures the bottom capacitor voltage and the total output current of the circuit to estimate the capacitance; at the same time, the auxiliary discharge circuit collects a small amount of data and does not require complex algorithms; it can obtain the operating status of the parallel capacitor relatively accurately, providing a basis for evaluating the operating status of the device. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a first flowchart illustrating the online capacitor capacitance monitoring method in this application embodiment;

[0034] Figure 2 This is a second flowchart illustrating the online capacitor capacitance monitoring method in the embodiments of this application;

[0035] Figure 3 This is a schematic diagram showing the relationship between the auxiliary discharge circuit, the first aluminum electrolytic capacitor, the second aluminum electrolytic capacitor, and the DC power supply in an application example of this application.

[0036] Figure 4 This is a logic diagram of the power converter in an application example of this application;

[0037] Figure 5 This is a schematic diagram of the structure of the online capacitor capacitance monitoring device in the embodiments of this application;

[0038] Figure 6 This is a schematic block diagram of the system configuration of an electronic device according to an embodiment of this application. Detailed Implementation

[0039] To enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of this application.

[0040] In existing technologies, quasi-online condition monitoring (CM) schemes for capacitors require specific conditions, such as startup, shutdown, and no-load operation. These conditions are typically not the normal operating conditions of the power converter. During normal online operation, the capacitor experiences varying voltage and current conditions, making it risky or inaccurate to estimate capacitance values ​​using charge-discharge curves. Furthermore, because quasi-online CM schemes rely on charge-discharge curves under specific conditions, they cannot provide continuous monitoring during normal capacitor operation. Under normal operating conditions, the capacitor's operating conditions are continuous and dynamically changing, and quasi-online CM schemes cannot capture and analyze charge-discharge curves in real time during these dynamic changes. Therefore, continuous capacitance estimation is not possible, making them unsuitable for online monitoring of capacitor values.

[0041] To address the problems existing in the prior art, this application provides a method, apparatus, system, and auxiliary discharge network for online monitoring of capacitor capacitance. This method enables online capacitance estimation of parallel capacitors based on large-signal transient trajectories. Through a simple and low-cost auxiliary discharge network, transient conditions can be generated without interrupting the normal operation of the converter. This method does not require a high sampling frequency; it only needs to measure the capacitor voltage and the circuit's output current. After identifying the functional relationship between capacitance and discharge time, the capacitance value is obtained by calculating a system of two equations.

[0042] The following examples illustrate this in detail.

[0043] To improve the reliability of capacitor condition monitoring by monitoring capacitor capacitance values ​​while the power converter is in online operation, this embodiment provides a method for online capacitor capacitance monitoring, where the executing entity is an online capacitor capacitance monitoring device. This online capacitor capacitance monitoring device includes, but is not limited to, a server, such as... Figure 1 As shown, this method specifically includes the following:

[0044] Step 100: When the power converter is in online operation, during the stage when the bipolar junction transistor is in the off state and the resistor is in operation, the DC power supply voltage is collected multiple times and the corresponding time points are recorded.

[0045] Specifically, when the power converter is in online operation, a microprocessor can be used to control the bipolar junction transistor to be in the off state, and the resistor to be in operation. The power converter can be a modular multilevel converter.

[0046] Step 200: Obtain the starting time of the stage when the bipolar junction transistor is in the off state and the resistor is in operation, the resistance value of the resistor, and the total output current of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor in the power converter.

[0047] Specifically, the time when the microprocessor controls the bipolar junction transistor to turn off can be taken as the starting time of the off-state and the resistor operation phase. The total output current of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor can be represented as the sum of the output currents of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor.

[0048] Step 300: Based on the starting time point, the total output current, the resistance value, the DC power supply voltage collected at each time, and their respective corresponding time points, monitor and determine the capacitance value of the first aluminum electrolytic capacitor and the capacitance value of the second aluminum electrolytic capacitor; wherein, the first capacitor branch and the second capacitor branch are connected in parallel with the DC power supply; the first capacitor branch includes: the resistor and the first aluminum electrolytic capacitor connected in series; the second capacitor branch includes: the second aluminum electrolytic capacitor; the bipolar junction transistor is connected in parallel with the resistor.

[0049] Specifically, during the period when the bipolar junction transistor is in the off state and the resistor is in operation, the total output current of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor can remain constant. It is understood that the first aluminum electrolytic capacitor is an aluminum electrolytic capacitor connected in series with the resistor in the power converter; the second aluminum electrolytic capacitor can be an aluminum electrolytic capacitor in the power converter connected in parallel with the first capacitor branch composed of the resistor and the first aluminum electrolytic capacitor; and the DC power supply can be a DC power supply in the power converter.

[0050] To estimate the capacitance of two parallel capacitors, such as Figure 2 As shown, in one embodiment, step 100 includes:

[0051] Step 101: When the power converter is in online operation, during the stage when the bipolar junction transistor is in the off state and the resistor is in operation, the DC power supply voltage is collected and recorded at any two time points.

[0052] To estimate the capacitance of two parallel capacitors, in one embodiment, step 300, which involves monitoring and determining the capacitance values ​​of the first and second aluminum electrolytic capacitors based on the starting time point, the total output current, the resistance value, the DC power supply voltage collected at each time, and their corresponding time points, includes:

[0053] The capacitance value C1 of the first aluminum electrolytic capacitor and the capacitance value C2 of the second aluminum electrolytic capacitor are determined according to the following formula:

[0054]

[0055] Among them, U SM1 (t) represents the DC power supply voltage collected for the first time, ta represents the time point at which the DC power supply voltage was collected for the first time, and U SM2 (t) represents the DC power supply voltage collected for the second time, tb represents the time point at which the DC power supply voltage was collected for the second time, I represents the total output current, R represents the resistance value, and t1 represents the starting time point.

[0056] Furthermore, this embodiment analyzes the capacitance estimation method for two parallel capacitors, and this scheme can also be extended to multiple parallel capacitors.

[0057] To further illustrate this solution, this application provides an application example of an online capacitor capacitance monitoring method, such as... Figure 3As shown, this method utilizes an auxiliary discharge network, consisting of a resistor R and a small-current negative-positive-negative NPN transistor Q (i.e., a bipolar junction transistor, BJT). The resistor R is connected in series with a first aluminum electrolytic capacitor C1. The capacitor branch formed by the resistor R and the first aluminum electrolytic capacitor C1, a second aluminum electrolytic capacitor C2, and a DC power supply U are also included. SM In parallel operation, the total output current I of the first and second aluminum electrolytic capacitors can be represented as the sum of the output currents I1 and I2 of the first and second aluminum electrolytic capacitors. Q is controlled by a microcontroller to charge and discharge C1 and C2. The entire measurement process is divided into three stages. The specific description is as follows:

[0058] Phase 1 [t0-t1]: The BJT is in the closed state, and resistor R is not connected to the circuit. After the Laplace transform, the current flowing through C1 and C2 and the output current can be expressed as:

[0059]

[0060] In the formula, I1(s) and I2(s) are the currents of C1 and C2, respectively, and U SM I(s) is the DC power supply voltage, I(s) is the output current of the circuit, s is the complex frequency, which is a variable after converting I from the time domain t to the complex frequency domain s, C1 is the capacitance of the first aluminum electrolytic capacitor, and C2 is the capacitance of the second aluminum electrolytic capacitor.

[0061] Phase 2 [t1-t2]: The BJT is in the off state, and R is in operation. At this time, the currents of C1 and C2 can be expressed as:

[0062]

[0063] Solving (2) yields:

[0064]

[0065] Transforming equation (3) into its time-domain form and assuming the output current I remains constant, we can obtain:

[0066]

[0067] Phase 3 [t2-t3]: The BJT is in the closed state, C1 begins to charge, and C2 begins to discharge. This time interval should be long enough to allow the voltage of C1 and C2 to return to U. SM (t).

[0068] Because aluminum electrolytic capacitors have a lifespan of thousands of hours, their capacitance changes slowly. To reduce power loss and voltage stress on C1 during charging / discharging, measurements are only performed a few times every few hours, each lasting only a few seconds.

[0069] The capacitance estimation is based on stage 2. It is achieved by measuring U at any two times between t1 and t2. SM Furthermore, by recording the time t and substituting it into formula (4), the capacitance values ​​of capacitors C1 and C2 can be calculated respectively. This allows for monitoring of the capacitors and provides a basis for evaluating their operating status. The structure of the power converter in this application example can be as follows: Figure 4 As shown, the power converter may include: bridge arm cp, bridge arm bp, bridge arm ap, bridge arm cn, bridge arm bn and bridge arm an. Bridge arm cn may include: valve tower 1 and valve tower 2. Valve tower 2 may include: multiple sub-modules SM1, SM2...SM k SM N SM k Including: Insulated Gate Bipolar Transistor (IGBT1 and IGBT2, etc.)

[0070] From a software perspective, in order to monitor the capacitance value of capacitors while the power converter is in online operation, thereby improving the reliability of capacitor condition monitoring, this application provides an embodiment of an online capacitor capacitance monitoring device for implementing all or part of the aforementioned online capacitor capacitance monitoring method. See [link to embodiment]. Figure 5 The online capacitor capacitance monitoring device specifically includes the following components:

[0071] The acquisition module 01 is used to acquire the DC power supply voltage multiple times and record the corresponding time points when the power converter is in the online operation state, during the stage when the bipolar junction transistor is in the off state and the resistor is in operation.

[0072] The acquisition module 02 is used to acquire the starting time of the stage when the bipolar junction transistor is in the off state and the resistor is in operation, the resistance value of the resistor, and the total output current of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor in the power converter.

[0073] The online monitoring module 03 is used to monitor and determine the capacitance values ​​of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor based on the start time point, the total output current, the resistance value, the DC power supply voltage collected each time, and their respective corresponding time points; wherein, the first capacitor branch and the second capacitor branch are connected in parallel with the DC power supply; the first capacitor branch includes: the resistor and the first aluminum electrolytic capacitor connected in series; the second capacitor branch includes: the second aluminum electrolytic capacitor; the bipolar junction transistor is connected in parallel with the resistor.

[0074] In one embodiment, the acquisition module includes:

[0075] The acquisition unit is used to acquire and record the DC power supply voltage at any two time points when the power converter is in online operation, during the stage when the bipolar junction transistor is in the off state and the resistor is in operation.

[0076] The embodiments of the capacitor capacitance online monitoring device provided in this specification can be used to execute the processing flow of the embodiments of the above-described capacitor capacitance online monitoring method. Its functions will not be repeated here, but can be referred to the detailed description of the embodiments of the above-described capacitor capacitance online monitoring method.

[0077] To further illustrate this solution, this application provides an embodiment of an auxiliary discharge network. In this embodiment, the auxiliary discharge network includes: a bipolar junction transistor and a resistor; the resistor is connected in series with a first aluminum electrolytic capacitor in a power converter to form a first capacitor branch; the first capacitor branch is connected in parallel with a second capacitor branch, the second capacitor branch including: a second aluminum electrolytic capacitor in the power converter; the bipolar junction transistor is connected in parallel with the resistor.

[0078] To further illustrate this solution, this application provides an embodiment of an online capacitor capacitance monitoring system. In this embodiment, the online capacitor capacitance monitoring system includes: a microcontroller, the auxiliary discharge network, and the online capacitor capacitance monitoring device; the controller is used to control the closing and opening of the bipolar transistor.

[0079] Figure 6 This is a schematic diagram of the physical structure of an electronic device provided in an embodiment of the present invention, such as... Figure 6 As shown, the electronic device includes: a memory 601, a processor 602, and a computer program stored in the memory 601 and executable on the processor 602. When the processor 602 executes the computer program, it implements the following method:

[0080] Step 100: When the power converter is in online operation, during the stage when the bipolar junction transistor is in the off state and the resistor is in operation, the DC power supply voltage is collected multiple times and the corresponding time points are recorded.

[0081] Step 200: Obtain the starting time of the stage when the bipolar junction transistor is in the off state and the resistor is in operation, the resistance value of the resistor, and the total output current of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor in the power converter.

[0082] Step 300: Based on the starting time point, the total output current, the resistance value, the DC power supply voltage collected at each time, and their respective corresponding time points, monitor and determine the capacitance value of the first aluminum electrolytic capacitor and the capacitance value of the second aluminum electrolytic capacitor; wherein, the first capacitor branch and the second capacitor branch are connected in parallel with the DC power supply; the first capacitor branch includes: the resistor and the first aluminum electrolytic capacitor connected in series; the second capacitor branch includes: the second aluminum electrolytic capacitor; the bipolar junction transistor is connected in parallel with the resistor.

[0083] This embodiment discloses a computer program product, which includes a computer program that, when executed by a processor, implements the following method:

[0084] Step 100: When the power converter is in online operation, during the stage when the bipolar junction transistor is in the off state and the resistor is in operation, the DC power supply voltage is collected multiple times and the corresponding time points are recorded.

[0085] Step 200: Obtain the starting time of the stage when the bipolar junction transistor is in the off state and the resistor is in operation, the resistance value of the resistor, and the total output current of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor in the power converter.

[0086] Step 300: Based on the starting time point, the total output current, the resistance value, the DC power supply voltage collected at each time, and their respective corresponding time points, monitor and determine the capacitance value of the first aluminum electrolytic capacitor and the capacitance value of the second aluminum electrolytic capacitor; wherein, the first capacitor branch and the second capacitor branch are connected in parallel with the DC power supply; the first capacitor branch includes: the resistor and the first aluminum electrolytic capacitor connected in series; the second capacitor branch includes: the second aluminum electrolytic capacitor; the bipolar junction transistor is connected in parallel with the resistor.

[0087] This embodiment provides a computer-readable storage medium storing a computer program that, when executed by a processor, implements the following method:

[0088] Step 100: When the power converter is in online operation, during the stage when the bipolar junction transistor is in the off state and the resistor is in operation, the DC power supply voltage is collected multiple times and the corresponding time points are recorded.

[0089] Step 200: Obtain the starting time of the stage when the bipolar junction transistor is in the off state and the resistor is in operation, the resistance value of the resistor, and the total output current of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor in the power converter.

[0090] Step 300: Based on the starting time point, the total output current, the resistance value, the DC power supply voltage collected at each time, and their respective corresponding time points, monitor and determine the capacitance value of the first aluminum electrolytic capacitor and the capacitance value of the second aluminum electrolytic capacitor; wherein, the first capacitor branch and the second capacitor branch are connected in parallel with the DC power supply; the first capacitor branch includes: the resistor and the first aluminum electrolytic capacitor connected in series; the second capacitor branch includes: the second aluminum electrolytic capacitor; the bipolar junction transistor is connected in parallel with the resistor.

[0091] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0092] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0093] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0094] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0095] In the description of this specification, the references to terms such as "an embodiment," "a specific embodiment," "some embodiments," "for example," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0096] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for online monitoring of capacitor capacitance, characterized in that, include: When the power converter is in online operation, during the stage when the bipolar junction transistor is in the off state and the resistor is in operation, the DC power supply voltage is sampled multiple times and the corresponding time points are recorded. The starting time of the phase in which the bipolar junction transistor is in the off state and the resistor is in operation, the resistance value of the resistor, and the total output current of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor in the power converter are obtained. Based on the starting time point, the total output current, the resistance value, the DC power supply voltage collected each time and their corresponding time points, the capacitance value of the first aluminum electrolytic capacitor and the capacitance value of the second aluminum electrolytic capacitor are monitored and determined. The first capacitor branch and the second capacitor branch are connected in parallel with the DC power supply; the first capacitor branch includes the resistor and the first aluminum electrolytic capacitor connected in series; the second capacitor branch includes the second aluminum electrolytic capacitor; and the bipolar junction transistor is connected in parallel with the resistor.

2. The online capacitor capacitance monitoring method according to claim 1, characterized in that, During the phase when the bipolar junction transistor is in the off state and the resistor is in operation, the DC power supply voltage is repeatedly sampled and recorded at the corresponding time points, including: When the power converter is in online operation, during the period when the bipolar junction transistor is in the off state and the resistor is in operation, the DC power supply voltage is collected and recorded at any two time points.

3. The online capacitor capacitance monitoring method according to claim 1, characterized in that, The step of monitoring and determining the capacitance values ​​of the first and second aluminum electrolytic capacitors based on the starting time point, the total output current, the resistance value, the DC power supply voltage collected at each time, and their corresponding time points includes: The capacitance value C1 of the first aluminum electrolytic capacitor and the capacitance value C2 of the second aluminum electrolytic capacitor are determined according to the following formula: Among them, U SM1 (t) represents the DC power supply voltage collected for the first time, t a U represents the time point at which the DC power supply voltage was first collected. SM2 (t) represents the DC power supply voltage collected in the second sampling, t b The time point at which the DC power supply voltage is collected for the second time is indicated, I represents the total output current, R represents the resistance value, and t1 represents the starting time point.

4. The online capacitor capacitance monitoring method according to claim 1, characterized in that, During the period when the bipolar junction transistor is in the off state and the resistor is in operation, the total output current of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor remains unchanged.

5. A capacitor capacitance value online monitoring device, characterized in that, include: The acquisition module is used to acquire the DC power supply voltage multiple times and record the corresponding time points when the power converter is in online operation, during the stage when the bipolar junction transistor is in the off state and the resistor is in operation. The acquisition module is used to acquire the starting time point of the stage when the bipolar junction transistor is in the off state and the resistor is in operation, the resistance value of the resistor, and the total output current of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor in the power converter. The online monitoring module is used to monitor and determine the capacitance values ​​of the first aluminum electrolytic capacitor and the second aluminum electrolytic capacitor based on the starting time point, the total output current, the resistance value, the DC power supply voltage collected each time and their corresponding time points. The first capacitor branch and the second capacitor branch are connected in parallel with the DC power supply; the first capacitor branch includes the resistor and the first aluminum electrolytic capacitor connected in series; the second capacitor branch includes the second aluminum electrolytic capacitor; and the bipolar junction transistor is connected in parallel with the resistor.

6. The online capacitor capacitance monitoring device according to claim 5, characterized in that, The acquisition module includes: The acquisition unit is used to acquire and record the DC power supply voltage at any two time points when the power converter is in online operation, during the stage when the bipolar junction transistor is in the off state and the resistor is in operation.

7. An auxiliary discharge network, characterized in that, include: Bipolar junction transistors and resistors; The resistor is connected in series with the first aluminum electrolytic capacitor in the power converter to form the first capacitor branch. The first capacitor branch is connected in parallel with the second capacitor branch, and the second capacitor branch includes: the second aluminum electrolytic capacitor in the power converter; The bipolar junction transistor is connected in parallel with the resistor.

8. A capacitor capacitance value online monitoring system, characterized in that, include: Microcontroller, the auxiliary discharge network of claim 7, and the online capacitor capacitance monitoring device of claim 5 or 6; The microcontroller is used to control the opening and closing of the bipolar junction transistor.

9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the online capacitor capacitance monitoring method according to any one of claims 1 to 4.

10. A computer-readable storage medium storing computer instructions thereon, characterized in that, When the instruction is executed by the processor, it implements the online capacitor capacitance monitoring method according to any one of claims 1 to 4.

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