Wind power converter direct current side capacitor temperature measuring method and device and storage medium

Abstract

The invention relates to the technical field of equipment state monitoring, in particular to a wind power converter direct current side capacitor temperature measuring method, device and equipment and a computer storage medium. According to the wind power converter direct current side capacitor temperature measuring method, the ripple current flowing through the direct current side capacitor is collected, then the hot spot temperature of the direct current side capacitor is analyzed, the hot spot temperature of the direct current side capacitor is accurately obtained, and therefore the electric thermal stress borne by the direct current side capacitor in the operation process is accurately reflected; and the method is of great significance to direct-current side capacitor reliability accurate evaluation.

Description

Technical Field

[0001] This invention relates to the field of equipment condition monitoring technology, and in particular to a method, apparatus, equipment, and computer storage medium for measuring the temperature of the DC-side capacitors of a wind power converter. Background Technology

[0002] Accurately obtaining the temperature of the DC-side capacitor, and thus accurately reflecting the electrothermal stress it experiences during operation, is of great significance for the accurate assessment of the reliability of the DC-side capacitor. However, in practical engineering, it is difficult to directly collect the temperature of the DC-side capacitor in the wind turbine converter system. Therefore, how to provide an accurate and timely indirect measurement method for the temperature of the DC-side capacitor is a problem that needs to be solved. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the problem of insufficient timeliness and accuracy of measurement in the prior art.

[0004] To solve the above-mentioned technical problems, the present invention provides a method for measuring the temperature of the DC-side capacitor of a wind power converter, comprising:

[0005] Construct an electrical model of the DC-side capacitor of the wind power converter;

[0006] The power loss of the DC-side capacitor is calculated based on the aforementioned electrical model;

[0007] Based on the power loss, a thermal model of the DC-side capacitor of the wind power converter is constructed.

[0008] The hot spot temperature of the DC-side capacitor is calculated based on the aforementioned thermal model.

[0009] Preferably, the electrical model for constructing the DC-side capacitor of the wind power converter includes:

[0010] Obtain the equivalent circuit parameters of the capacitor, including the equivalent series resistance, equivalent series inductance, and capacitance.

[0011] A circuit model is established based on the equivalent circuit parameters, including an ideal capacitor and a resistor and an inductor connected in series across the ideal capacitor.

[0012] Preferably, the calculation of the power loss of the DC-side capacitor based on the electrical model includes:

[0013] Based on the circuit model, a mathematical model is established between power loss, ripple current value and the equivalent series resistance value of the capacitor.

[0014] Preferably, establishing a mathematical model based on the circuit model to establish the relationship between power loss, ripple current, and the equivalent series resistance of the capacitor includes:

[0015] Based on the circuit model, the power loss is determined to be equal to the product of the square of the ripple current and the equivalent series resistance of the capacitor.

[0016] Preferably, the step of constructing a thermal model of the DC-side capacitor of the wind power converter based on the power loss includes:

[0017] Determine the thermal resistance and thermal capacity of the capacitor;

[0018] A thermal network is constructed based on the thermal resistance and thermal capacity, connecting the capacitor hot spot temperature, the casing temperature, and the ambient temperature.

[0019] Based on the aforementioned thermal network and heat transfer equation, a mathematical model is established relating the capacitor hot spot temperature, the total thermal resistance of the capacitor, the power loss, and the ambient temperature.

[0020] Preferably, the mathematical model established based on the thermal network and heat transfer equations, relating the capacitor hotspot temperature, the total thermal resistance of the capacitor, the power loss, and the ambient temperature, includes:

[0021] The hot spot temperature of the capacitor is determined to be equal to the sum of the product of the power loss and the total thermal resistance of the capacitor and the ambient temperature.

[0022] Preferably, the total thermal resistance of the capacitor includes the thermal resistance from the hot spot to the casing and the thermal resistance from the casing to the environment.

[0023] The present invention also provides a device for measuring the temperature of the DC-side capacitor of a wind power converter, comprising:

[0024] The electrical model building module is used to build an electrical model of the DC-side capacitor of a wind power converter.

[0025] A power loss calculation module is used to calculate the power loss of the DC-side capacitor based on the electrical model.

[0026] A thermal model building module is used to build a thermal model of the DC-side capacitor of the wind power converter based on the power loss.

[0027] The hot spot temperature calculation module is used to calculate the hot spot temperature of the DC-side capacitor based on the thermal model.

[0028] The present invention also provides a device for measuring the temperature of the DC-side capacitor of a wind power converter, comprising:

[0029] Memory, used to store computer programs;

[0030] A processor is used to execute the computer program to implement the steps of the above-described method for measuring the temperature of the DC-side capacitor of a wind power converter.

[0031] The present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the above-described method for measuring the temperature of the DC-side capacitor of a wind power converter.

[0032] The technical solution of the present invention has the following advantages over the prior art:

[0033] The method for measuring the temperature of the DC-side capacitor of a wind power converter described in this invention collects the ripple current flowing through the DC-side capacitor and then analyzes the hot spot temperature of the DC-side capacitor, accurately obtaining the hot spot temperature of the DC-side capacitor. This accurately reflects the electrothermal stress borne by the DC-side capacitor during operation, which is of great significance for the accurate assessment of the reliability of the DC-side capacitor. Attached Figure Description

[0034] To make the content of this invention easier to understand, the invention will be further described in detail below with reference to specific embodiments and accompanying drawings, wherein:

[0035] Figure 1 This is a schematic diagram showing the location and structure of the DC-side capacitors in a wind power converter;

[0036] Figure 2 This is a flowchart illustrating the implementation of a method for measuring the temperature of the DC-side capacitor in a wind power converter, as provided by this invention.

[0037] Figure 3 It is an electrical and thermal model for estimating the temperature of the DC-side capacitors in a wind power converter. Detailed Implementation

[0038] The core of this invention is to provide a method, device, equipment, and computer storage medium for measuring the temperature of the DC-side capacitor in a wind power converter, which effectively and accurately obtains the hot spot temperature of the DC-side capacitor.

[0039] To enable those skilled in the art to better understand the present invention, the invention will be further described in detail below with reference to the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] like Figure 1 , Figure 1This is a schematic diagram of the location and structure of the DC-side capacitor in a wind power converter. The entire wind power converter consists of a wind turbine (101), a rectifier (102), a DC-side capacitor (103), an inverter (104), and a grid-side filter assembly (105). The DC-side capacitor (103) is responsible for both the output power of the rectifier (102) and the input power of the inverter (104), and is one of the core components for power conversion in the wind power converter.

[0041] Please refer to Figure 2 , Figure 2 The flowchart illustrates the implementation of a method for measuring the temperature of the DC-side capacitor in a wind power converter, as provided by this invention. The specific operation steps are as follows:

[0042] S101: Construct an electrical model of the DC-side capacitor of the wind power converter;

[0043] S102: Calculate the power loss of the DC-side capacitor based on the electrical model;

[0044] S103: Based on the power loss, construct a thermal model of the DC-side capacitor of the wind power converter;

[0045] S104: Calculate the hot spot temperature of the DC-side capacitor based on the thermal model.

[0046] like Figure 3 , Figure 3 Electrical and thermal models for estimating the temperature of the DC-side capacitors in wind power converters.

[0047] Based on the above embodiments, this embodiment will provide a detailed description of step S101:

[0048] 1. Obtain the equivalent circuit parameters of the capacitor, including the equivalent series resistance, equivalent series inductance, and capacitance:

[0049] Electrical models typically begin by determining the equivalent circuit parameters of the capacitor, which include:

[0050] Equivalent series resistance (ESR): The resistance inside a capacitor, which leads to power loss and heat generation.

[0051] Equivalent series inductance (ESL): The inductance inside a capacitor affects the rate of change of current.

[0052] Capacitance (C): The ability of a capacitor to store electrical charge.

[0053] 2. Establish a circuit model based on the equivalent circuit parameters, including an ideal capacitor and a resistor and inductor connected in series across the ideal capacitor:

[0054] Based on the above parameters, a simplified circuit model can be constructed, which typically includes:

[0055] ESR: Resistance connected in series across the capacitor.

[0056] ESL: Inductance connected in series across the capacitor.

[0057] The values ​​of the above parameters can be obtained from the performance parameter table of the device provided by the manufacturer.

[0058] Ideal capacitor (C): An ideal capacitor element, without considering the effects of ESR and ESL.

[0059] Based on experience, when the voltage across the DC-side capacitor remains stable, the higher the output power of the converter, the higher the ripple current flowing through the capacitor. Due to the effect of its equivalent series resistance, the DC-side capacitor will generate greater power loss, resulting in a higher capacitor temperature and thus shortening the capacitor's lifespan.

[0060] 3. Consider the impact of ripple current:

[0061] Ripple current is the result of voltage fluctuations on the DC-side capacitor, and it has a direct impact on the capacitor's power loss and temperature.

[0062] Therefore, the electrical model needs to consider the magnitude and frequency of the ripple current.

[0063] Ripple current (I ripple ): The AC component flowing through the capacitor is usually generated by the switching action of the converter.

[0064] Based on the above embodiments, this embodiment will provide a detailed description of step S102:

[0065] The power loss of the capacitor is mainly caused by ESR. Based on the circuit model, a mathematical model is established between the power loss, ripple current, and the equivalent series resistance of the capacitor:

[0066] Based on the circuit model, the power loss is determined to be equal to the product of the square of the ripple current and the equivalent series resistance of the capacitor:

[0067] P loss =I ripple 2 ×ESR

[0068] Among them, P loss It is power loss, I ripple It is the ripple current, and ESR is the equivalent series resistance.

[0069] Based on the above embodiments, this embodiment will provide a detailed description of step S103:

[0070] 1. Determine thermal resistance and heat capacity:

[0071] The construction of a thermal model first requires determining the thermal resistance and thermal capacity of the capacitor, which describe how the capacitor responds to temperature changes:

[0072] Thermal resistance (Rth): Describes the resistance to heat transfer from the hot spot of a capacitor to the environment. It typically includes the thermal resistance from the hot spot to the casing (Rthhc) and the thermal resistance from the casing to the environment (Rthca).

[0073] Heat capacity (Cth): describes the ability of a capacitor to store heat.

[0074] 2. Construct a thermal network between the capacitor hotspot temperature, the casing temperature, and the ambient temperature based on the aforementioned thermal resistance and thermal capacitance.

[0075] Constructing a thermal network using thermal resistance and thermal capacity typically includes:

[0076] Capacitor hot spot (Th): The highest temperature point inside a capacitor.

[0077] Case temperature (Tc): The temperature of the capacitor case.

[0078] Ambient temperature (Ta): The ambient temperature at which the capacitor is located.

[0079] 3. Consider the heat generated by power loss.

[0080] The power loss of a capacitor is converted into heat, which is a key input in the thermal model. The power loss can be calculated using the electrical model.

[0081] Based on the above embodiments, this embodiment will provide a detailed description of step S104:

[0082] Based on the aforementioned thermal network and heat transfer equations, a mathematical model is established relating the capacitor hotspot temperature, the total thermal resistance of the capacitor, the power loss, and the ambient temperature:

[0083] The heat transfer equation is used to describe the flow of heat between the inside of a capacitor and its surroundings. This typically involves heat transfer mechanisms such as conduction, convection, and radiation.

[0084]

[0085] The capacitor hotspot temperature is determined to be equal to the sum of the product of the power loss and the total thermal resistance of the capacitor and the ambient temperature.

[0086] Th = P loss Rth+Ta

[0087] Among them, P loss Rth is the power loss, Th is the hot spot temperature of the capacitor, Ta is the ambient temperature, and Rth is the total thermal resistance. The total thermal resistance of the capacitor includes the thermal resistance from the hot spot to the casing and the thermal resistance from the casing to the environment.

[0088] A higher hotspot temperature (Th) value of the DC-side capacitor indicates higher thermal stress on the capacitor. Analyzing the ripple current and hotspot temperature during DC-side capacitor operation reflects the magnitude of electrical and thermal stresses experienced by the capacitor. High electrical and thermal stresses exacerbate capacitor fatigue, making the DC-side capacitor more prone to failure. Therefore, by combining the capacitor's thermal model with the collection of ripple current and hotspot temperature information for the DC-side capacitor, a data foundation can be provided for reliability assessment and condition monitoring.

[0089] This invention provides a device for measuring the temperature of the DC-side capacitor in a wind power converter; the specific device may include:

[0090] The electrical model building module is used to build an electrical model of the DC-side capacitor of a wind power converter.

[0091] A power loss calculation module is used to calculate the power loss of the DC-side capacitor based on the electrical model.

[0092] A thermal model building module is used to build a thermal model of the DC-side capacitor of the wind power converter based on the power loss.

[0093] The hot spot temperature calculation module is used to calculate the hot spot temperature of the DC-side capacitor based on the thermal model.

[0094] The wind power converter DC-side capacitor temperature measuring device of this embodiment is used to implement the aforementioned wind power converter DC-side capacitor temperature measuring method. Therefore, the specific implementation of the wind power converter DC-side capacitor temperature measuring device can be found in the previous embodiment section of the wind power converter DC-side capacitor temperature measuring method. For example, the electrical model construction module, power loss calculation module, thermal model construction module, and hot spot temperature calculation module are respectively used to implement steps S101, S102, S103, and S104 in the above-mentioned wind power converter DC-side capacitor temperature measuring method. Therefore, its specific implementation can be referred to the description of the corresponding embodiments, and will not be repeated here.

[0095] A specific embodiment of the present invention also provides a wind power converter DC-side capacitor temperature measurement device, comprising: a memory for storing a computer program; and a processor for executing the computer program to implement the steps of the above-described wind power converter DC-side capacitor temperature measurement method.

[0096] A specific embodiment of the present invention also provides a computer-readable storage medium storing a computer program, which, when executed by a processor, implements the steps of the above-described method for measuring the temperature of the DC-side capacitor of a wind power converter.

[0097] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application 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.

[0098] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. 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... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0099] 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.

[0100] 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.

[0101] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for measuring the temperature of the DC-side capacitor in a wind power converter, characterized in that, include: Construct an electrical model of the DC-side capacitor of the wind power converter; The power loss of the DC-side capacitor is calculated based on the aforementioned electrical model; Based on the power loss, a thermal model of the DC-side capacitor of the wind power converter is constructed. The hot spot temperature of the DC-side capacitor is calculated based on the aforementioned thermal model.

2. The method for measuring the temperature of the DC-side capacitor of a wind power converter according to claim 1, characterized in that, The electrical model for constructing the DC-side capacitor of the wind power converter includes: Obtain the equivalent circuit parameters of the capacitor, including the equivalent series resistance, equivalent series inductance, and capacitance. A circuit model is established based on the equivalent circuit parameters, including an ideal capacitor and a resistor and an inductor connected in series across the ideal capacitor.

3. The method for measuring the temperature of the DC-side capacitor of a wind power converter according to claim 2, characterized in that, The calculation of power loss of the DC-side capacitor based on the electrical model includes: Based on the circuit model, a mathematical model is established between power loss, ripple current value and the equivalent series resistance value of the capacitor.

4. The method for measuring the temperature of the DC-side capacitor of a wind power converter according to claim 3, characterized in that, The mathematical model established based on the circuit model, relating power loss, ripple current, and the equivalent series resistance of the capacitor, includes: Based on the circuit model, the power loss is determined to be equal to the product of the square of the ripple current and the equivalent series resistance of the capacitor.

5. The method for measuring the temperature of the DC-side capacitor of a wind power converter according to claim 1, characterized in that, The construction of the thermal model for the DC-side capacitor of the wind power converter based on the power loss includes: Determine the thermal resistance and thermal capacity of the capacitor; A thermal network is constructed based on the thermal resistance and thermal capacity, connecting the capacitor hot spot temperature, the casing temperature, and the ambient temperature. Based on the aforementioned thermal network and heat transfer equation, a mathematical model is established relating the capacitor hot spot temperature, the total thermal resistance of the capacitor, the power loss, and the ambient temperature.

6. The method for measuring the temperature of the DC-side capacitor of a wind power converter according to claim 5, characterized in that, The mathematical model established based on the thermal network and heat transfer equations, relating the capacitor hotspot temperature, total capacitor thermal resistance, power loss, and ambient temperature, includes: The hot spot temperature of the capacitor is determined to be equal to the sum of the product of the power loss and the total thermal resistance of the capacitor and the ambient temperature.

7. The method for measuring the temperature of the DC-side capacitor of a wind power converter according to claim 6, characterized in that, The total thermal resistance of the capacitor includes the thermal resistance from the hot spot to the casing and the thermal resistance from the casing to the environment.

8. A device for measuring the temperature of the DC-side capacitor of a wind power converter, characterized in that, include: The electrical model building module is used to build an electrical model of the DC-side capacitor of a wind power converter. A power loss calculation module is used to calculate the power loss of the DC-side capacitor based on the electrical model. A thermal model building module is used to build a thermal model of the DC-side capacitor of the wind power converter based on the power loss. The hot spot temperature calculation module is used to calculate the hot spot temperature of the DC-side capacitor based on the thermal model.

9. A device for measuring the temperature of the DC-side capacitor of a wind power converter, characterized in that, include: Memory, used to store computer programs; A processor, configured to execute the computer program to implement the steps of the method for measuring the DC-side capacitor temperature of a wind power converter as described in any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, The computer-readable storage medium stores a computer program that, when executed by a processor, implements the steps of the wind power converter DC-side capacitor temperature measurement method as described in any one of claims 1 to 7.

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