Heat dissipation method and heat dissipation system for frequency converter

Abstract

The present application relates to the field of inverter heat dissipation technology, and specifically to a heat dissipation method and a heat dissipation system for an inverter, the method comprising: real-time acquisition of the current inverter's core substrate temperature, internal ambient temperature, and input power; analysis of the acquired data to assess the insufficient heat dissipation inside the inverter and the efficiency difference between heat generation and heat dissipation; adjustment of the proportional gain Kp in the PID controller according to the difference in heat radiation efficiency to control the heat dissipation intensity of the inverter. The present application aims to utilize the relationship between the heat generation of the inverter's internal components and the heat dissipation intensity to enhance the inverter's responsiveness to heat dissipation intensity control.

Description

Technical Field

[0001] The present application relates to the technical field of inverter heat dissipation, and in particular to a heat dissipation method and a heat dissipation system for an inverter. Background Art

[0002] The inverter improves the process level and product quality by adjusting the running speed of the motor, while achieving significant energy-saving effects. With the rapid development of power electronics and microelectronics, the application of inverters is becoming more and more extensive. The thermal design of its power devices is directly related to the reliability and stability of the equipment. Since the inverter generates a lot of waste heat during the power conversion process, even if the efficiency loss is low, it will cause several kilowatts to tens of kilowatts of heat to be generated. Therefore, heat dissipation has become a key issue in the design and application of inverters.

[0003] As one of the main means of cooling electronic devices, the efficiency of convection cooling technology is significantly affected by the characteristics of air flow. In the case of high heat flux density, traditional gas forced convection cooling may not meet the heat dissipation requirements, especially when the computer is running large software, which is prone to thermal spikes, causing the device to overheat or even crash.

[0004] In the prior art, the heat dissipation intensity control of the convection heat dissipation equipment often only considers the temperature changes inside the inverter. The power consumption of the electronic devices in the inverter directly affects the heat intensity. The prior art does not focus on the relationship between the heat generation of the internal components of the inverter and the heat dissipation intensity, which leads to poor control of the heat dissipation intensity of the inverter. Summary of the invention

[0005] In order to solve the above technical problems, the present application provides a heat dissipation method and a heat dissipation system for a frequency converter, and the technical solutions adopted are as follows:

[0006] In a first aspect, an embodiment of the present application provides a heat dissipation method for a frequency converter, the method comprising the following steps:

[0007] Real-time collection of the current inverter's movement substrate temperature, internal ambient temperature and input power;

[0008] Analyze the correlation between the movement substrate temperature and the internal ambient temperature; calculate the ratio of the extreme values ​​of the two data in the same time window; determine whether the slopes of the fitted straight lines of the two data in the same time window have the same sign to determine the determination factor of the time window; reversely fuse the determination factors and ratios calculated in all the same time windows sliding on the two data, and then forwardly fuse the results with the correlation to obtain the heat dissipation defect index of the current inverter;

[0009] Obtain the extreme points of all calculated heat dissipation defect indexes; in a time window centered on each extreme point, use all corresponding power data and heat dissipation defect indexes as independent variables and dependent variables for straight line fitting, and calculate the mean square error of the fitting straight line; calculate the similarity between all corresponding power data and heat dissipation defect indexes; reversely fuse the similarity of all time windows centered on the extreme point with the mean square error to obtain the difference in thermal radiation efficiency of the inverter;

[0010] The proportional gain Kp in the PID controller is adjusted according to the difference in heat radiation efficiency to control the heat dissipation intensity of the inverter.

[0011] Preferably, the determination method of the determination factor of the time window is: if the slopes of the fitted straight lines of the two types of data in the same time window have the same sign, the determination factor of the time window is set to a value of 1; otherwise, it is set to a value of 0.

[0012] Preferably, the heat dissipation defect index of the current inverter is recorded as A, ;in, is the normalized function, a is the correlation between the movement substrate temperature and the internal ambient temperature, K is the number of sliding time windows, is the ratio of the extreme difference between the movement substrate temperature and the internal ambient temperature in the kth time window, is the determination factor of the kth time window, Adjust the parameters for the preset denominator.

[0013] Preferably, the sliding method is to use a preset time period as a sliding step and slide the time window in the order of the collection time from small to large.

[0014] Preferably, the heat radiation efficiency difference of the inverter is recorded as B, ; Where P is the number of time windows centered on the extreme point, is the similarity calculated in the pth time window centered on the extreme point, e is a natural constant, is the mean square error calculated in the pth time window centered at the extreme point.

[0015] Preferably, the extreme value point is obtained from a sequence of all calculated heat dissipation defect indexes sorted in chronological order.

[0016] Preferably, the size of the time window constructed with each extreme point as the center does not have the same value relationship as the size of the time window when analyzing the two types of data.

[0017] Preferably, the adjustment relationship of the proportional gain Kp is: ;in, is the adjusted proportional gain Kp, is a preset adjustment parameter, B is the heat radiation efficiency difference of the inverter; wherein, the initial value of Kp is a preset value.

[0018] Preferably, the method for adjusting the proportional gain Kp in the PID controller according to the difference in heat radiation efficiency to control the heat dissipation intensity of the inverter is:

[0019] The preset integral gain Ki, the initial value of the differential gain Kd and the adjusted proportional gain Kp are used as the input of the PID controller, and the improved PID controller is used to output a control signal, which is used to control the heat dissipation intensity of the inverter heat dissipation system.

[0020] In a second aspect, another embodiment of the present application further provides a heat dissipation system for a frequency converter, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein when the processor executes the computer program, any one of the heat dissipation methods for a frequency converter described above is implemented.

[0021] This application has at least the following beneficial effects:

[0022] The present application proposes a heat dissipation method and a heat dissipation system for a frequency converter. To address the problems of insufficient heat dissipation inside the frequency converter and the efficiency difference between heat generation and heat dissipation, Pearson correlation analysis, time window analysis and least squares straight line fitting methods are used to reflect the overall relationship between the internal heat generation capacity and heat dissipation capacity of the frequency converter, thereby solving the problem of heat dissipation system performance evaluation. To address the correlation problem between the heat generation efficiency and heat dissipation efficiency caused by the power consumption of the frequency converter, an extreme point detection algorithm, least squares straight line fitting and cosine similarity calculation method are used to reflect the synchronization and correlation between power changes and heat dissipation defect changes under special circumstances, thereby eliminating interference from non-related factors. By improving the PID controller, the proportional gain Kp is adjusted according to the thermal radiation efficiency difference B to achieve adaptive control of the heat dissipation intensity of the frequency converter, thereby enhancing the response capability of the frequency converter to internal heat generation changes and improving the stability and reliability of the system. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions and advantages in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the prior art descriptions are briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0024] Figure 1 A flow chart of a heat dissipation method for a frequency converter provided in one embodiment of the present application;

[0025] Figure 2A flowchart of a specific implementation method for controlling the heat dissipation intensity of a frequency converter provided in this application. DETAILED DESCRIPTION

[0026] Example 1

[0027] An embodiment of the present application provides a heat dissipation method for a frequency converter, for details, see Figure 1 , the method comprises the following steps:

[0028] Step 1: Collect the current inverter's movement substrate temperature, internal ambient temperature, and input power in real time.

[0029] In order to explore the heating state of the inverter, a temperature sensor is installed on the inverter movement substrate to monitor the heating data of the main components when the inverter is running; a temperature sensor is installed in the inner cavity of the inverter to monitor the temperature of the internal environment of the inverter; a power analyzer is installed at the input end of the inverter to monitor the input power of the inverter.

[0030] In this embodiment, the acquisition frequency of the core substrate temperature, internal environment temperature and input power is set to 20 Hz, and all the collected data are normalized as a whole to eliminate the influence of dimension.

[0031] Step 2: Analyze the collected data to evaluate the insufficient heat dissipation inside the inverter and the efficiency difference between heat generation and heat dissipation.

[0032] The temperature of the movement substrate mainly reflects the heating state of the key electronic components inside the inverter, while the internal ambient temperature represents the overall thermal environment of the inverter. When the substrate temperature rises, it usually means that the power consumption of the electronic components increases and more heat is generated, which will directly affect the increase in the internal ambient temperature. When the internal environment is too high, it will cause the temperature of the components inside the inverter to be too high, thus generating a positive feedback phenomenon. During the normal operation of the inverter, the convection heat dissipation equipment will reduce the temperature inside the inverter. When the heat dissipation capacity exceeds the heat generation capacity of the inverter substrate, the temperature inside the inverter will be effectively controlled. When the heat dissipation capacity is lower than the heat generation capacity of the inverter substrate, the internal temperature of the inverter will not decrease significantly, and may even rise.

[0033] In this application, the specific implementation method flow chart of controlling the heat dissipation intensity of the inverter by utilizing the heat dissipation and heating capacity of the inverter is as shown in the attached figure. Figure 2 shown.

[0034] In order to quantify the relationship between the heating capacity and heat dissipation capacity of the inverter cavity, as a preferred implementation mode, the present application analyzes the correlation between the movement substrate temperature and the internal ambient temperature; calculates the ratio of the extreme values ​​of the two data in the same time window; determines whether the slopes of the fitted straight lines of the two data in the same time window have the same sign to determine the determination factor of the time window; reversely fuses the determination factors and ratios calculated in all the same time windows sliding on the two data, and then forward fuses the results with the correlation to obtain the heat dissipation defect index of the current inverter.

[0035] It can be understood that fusion can be divided into forward fusion and reverse fusion. Forward fusion is a fusion method such as addition and multiplication between data, and reverse fusion is a fusion method such as subtraction and division between data. The specific forward fusion and reverse fusion methods are determined by the implementer according to actual conditions, and this application does not impose any special restrictions.

[0036] In this embodiment, specifically:

[0037] Taking all the currently collected movement substrate temperatures and internal environment temperatures as input, a correlation analysis algorithm is used to output the correlation between the two data, and the correlation can reflect the overall relationship between the heating capacity and the heat dissipation capacity. In this embodiment, the Pearson correlation coefficient can be used. In other embodiments, the correlation can also be calculated by covariance and chi-square test.

[0038] Furthermore, a time window with a time length of N is set. In this embodiment, N is taken as 20. The time window is traversed in order from small to large with a step length of 1 acquisition time, wherein the starting point of the time window is the initial acquisition time of the two types of data, and the end point of the time window is the cutoff acquisition time of the two types of data. It is assumed that the time window slides K-1 times in the two types of data, that is, there are K time windows in total, and the range of the two types of data in the same time window is calculated respectively, and the ratio of the range of the movement substrate temperature to the range of the internal environment temperature in the same time window is calculated. When the change trends of the two types of data are consistent, it means that the positive feedback generated by the substrate temperature on the inner cavity temperature has not been effectively offset by the heat dissipation system. Among them, the size of the time window and the sliding step can be set by the implementer.

[0039] Furthermore, the least squares method is used to fit the two data in the same time window as input, and the slopes of the fitted lines of the two data are output. When the slopes of the fitted lines of the two data have the same sign, the determination factor of the time window is set to a value of 1; otherwise, it is set to a value of 0.

[0040] Furthermore, based on the above analysis, the heat dissipation defect index of the current inverter is calculated and recorded as A. ;in, is the normalized function, a is the correlation between the movement substrate temperature and the internal ambient temperature, K is the number of sliding time windows, is the ratio of the extreme difference between the movement substrate temperature and the internal ambient temperature in the kth time window, is the determination factor of the kth time window, is a preset denominator adjustment parameter, and in this embodiment, the value is 0.01, in order to prevent the denominator from being 0. Among them, the normalization function in this embodiment is the minimum and maximum normalization, and in other embodiments, the maximum absolute value normalization can also be used to map the value range to Method within.

[0041] It should be understood that a reflects the overall relationship between the inverter's internal heating capacity and heat dissipation capacity, which is expressed by the normalized function Map the value of a to The larger the value of a, the stronger the positive feedback, that is, the poor operation of the cooling system, the heat dissipation capacity is significantly less than the heating capacity, which will lead to an increase in the A value, indicating a high heat dissipation defect index; b reflects the degree of influence of the rise in the inverter substrate temperature on the change in the inner cavity temperature. The smaller the value of b, the greater the change in the internal environment is than the change in the substrate temperature. The same trend screening of the two is performed through c, so when b is smaller, the greater the degree of influence of heat on heat dissipation, the poor operation of the cooling system, and the increase in the A value. A, as a heat dissipation defect index, comprehensively reflects the performance of the inverter's internal heat dissipation system. The higher the A value, the poor operation of the cooling system, the greater the heat dissipation capacity is significantly less than the heating capacity, and there is a large heat dissipation defect, which may cause the internal temperature of the inverter to be too high, affecting the stable operation of the equipment.

[0042] During the operation of the inverter, the input power reflects the electric energy consumed by the inverter during operation, and most of this electric energy will be converted into heat energy, causing the internal temperature of the inverter to rise. The heat dissipation defect index A is a comprehensive indicator to measure the performance of the internal heat dissipation system of the inverter. It analyzes the relationship between the movement substrate temperature and the internal ambient temperature, as well as their changing trends, to evaluate whether the heat dissipation system can effectively discharge this heat. When the input power shows a higher power consumption, it means that the heat generated inside the inverter increases (not only the movement substrate temperature rises), which will increase the burden on the heat dissipation system.

[0043] Accordingly, based on the above analysis, as a preferred implementation mode, the present application obtains the extreme points in all calculated heat dissipation defect indexes; within the time window centered on each extreme point, all corresponding power data and heat dissipation defect indexes are used as independent variables and dependent variables for straight line fitting, and the mean square error of the fitting straight line is calculated; the similarity between all corresponding power data and heat dissipation defect indexes is calculated; the similarity of all time windows centered on the extreme point is reversely fused with the mean square error to obtain the difference in thermal radiation efficiency of the inverter.

[0044] In this embodiment, specifically:

[0045] All calculated heat dissipation defect indexes are obtained and sorted in the order of acquisition time to obtain a sequence, which is recorded as a heat dissipation defect sequence.

[0046] As analyzed above, the greater the input power of the inverter, the higher the heat generated. In order to analyze the relationship between the input power of the inverter and the heat dissipation defect, the extreme point detection algorithm is used to output the extreme point of the heat dissipation defect sequence with the heat dissipation defect sequence as input. The extreme point represents the special case of the heat dissipation defect.

[0047] Furthermore, a time window is constructed with each extreme point as the center to more carefully analyze the relationship between the inverter input power and the heat dissipation defects under special circumstances. The size of the time window can take different values ​​from the size of the time window when analyzing the two data of the movement substrate temperature and the internal ambient temperature. In this embodiment, the size of the time window constructed with the extreme point as the center is 9 time lengths, and other embodiments can be set according to actual conditions.

[0048] The input power and the heat dissipation defect index in the time window centered at each extreme point are used as input, the input power is used as the independent variable, and the heat dissipation defect index is used as the dependent variable. The least squares straight line fitting is used to output the mean square error d of the fitting straight line. Among them, the least squares straight line fitting is a well-known technology and will not be described in detail. In other embodiments, the linear regression method can also be used.

[0049] The input power and the heat dissipation defect index in each time window are used as input to calculate the similarity between them. In this embodiment, the cosine similarity is used for calculation, and in other embodiments, the DTW distance can also be used for calculation.

[0050] Furthermore, based on the above analysis, the difference in heat radiation efficiency of the inverter is calculated and recorded as B. ; Where P is the number of time windows centered on the extreme point, is the similarity calculated in the pth time window centered on the extreme point, e is a natural constant, is the mean square error calculated in the pth time window centered at the extreme point.

[0051] It should be understood that d reflects the error degree of the fitting straight line between the input power and the heat dissipation defect index. The smaller the value of d, the more accurately the fitting straight line can reflect the relationship between the input power and the heat dissipation defect index, and the greater the influence of the input power on the heat dissipation defect, that is, the greater the heating efficiency of the inverter is than the heat dissipation efficiency, the greater the difference in thermal radiation efficiency, and the larger the B value; f reflects the synchronization between the change of the input power of the inverter and the change of the heat dissipation defect index. The larger the value of f, the stronger the consistency of the change trend between the input power and the heat dissipation defect, indicating that the change of power is more closely related to the change of heat dissipation defect, and the larger the B value. B represents the difference in thermal radiation efficiency. The larger the B value, the stronger the correlation between the heating efficiency and the heat dissipation efficiency caused by the power consumption of the inverter under special circumstances, that is, the increase in power is more likely to lead to an increase in heat dissipation defects.

[0052] In other embodiments, the expression of the heat radiation efficiency difference B of the inverter can also be set as .

[0053] Step 3: Adjust the proportional gain Kp in the PID controller according to the difference in heat radiation efficiency to control the heat dissipation intensity of the inverter.

[0054] As described in the background technology, the prior art does not focus on the relationship between the heat generation of the internal components of the inverter and the heat dissipation intensity, resulting in poor heat dissipation efficiency. An improved PID algorithm is now proposed, which enables the inverter to adaptively adjust the heat dissipation intensity according to the relationship between the heat generation efficiency and the heat dissipation efficiency of the internal components.

[0055] As a preferred implementation, the present application combines the preset integral gain Ki, the initial value of the differential gain Kd and the adjusted proportional gain Kp as the input of the PID controller, and uses the improved PID controller to output a control signal, which is used to control the heat dissipation intensity of the inverter heat dissipation system. The specific improvement method in this embodiment is as follows:

[0056] The heat dissipation intensity of the inverter is controlled using an initial PID algorithm, and the initial value of the PID algorithm is set. Specifically, in this embodiment, the initial value of the proportional gain Kp is set to 0.5, the initial value of the integral gain Ki is set to 0.125, and the initial value of the differential gain Kd is set to 0.1.

[0057] Since Kp determines the linear relationship between the controller output and the error, a larger Kp can improve the system's response speed and steady-state accuracy. Conversely, based on B, Kp is adjusted. The specific proportional gain Kp adjustment relationship is: ;in, is the adjusted proportional gain Kp, is a preset adjustment parameter, B is the heat radiation efficiency difference of the inverter; wherein, the initial value of Kp is a preset value.

[0058] It should be understood that adjusting the parameters , used to map B to a certain range. In this embodiment The value is 1.4, and the specific value can be adjusted according to the actual situation. Kp determines the linear relationship between the controller output and the error. The larger B is, the greater the impact of the inverter's heating efficiency on the heat dissipation efficiency, that is, an increase in power is more likely to lead to an increase in heat dissipation defects, which means that the inverter's heat dissipation system needs to respond more actively to the increase in heat to avoid overheating. At this time, increasing Kp will enhance the controller's response to the error, allowing the heat dissipation system to adjust the heat dissipation intensity more quickly to cope with greater heating efficiency, and vice versa.

[0059] With the preset integral gain Ki, the initial value of the differential gain Kd and the improved proportional gain Kp as input, the improved PID controller is used to output a control signal, which will be applied to the cooling system of the inverter, thereby adjusting the fan speed or the working efficiency of the heat sink to reduce the actual temperature of the inverter, which is used to control the heat dissipation intensity of the inverter.

[0060] Example 2

[0061] Based on the same inventive concept as the above method, an embodiment of the present application also provides a heat dissipation system for a frequency converter, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, wherein the processor implements any one of the above-mentioned heat dissipation methods for a frequency converter when executing the computer program.

[0062] Those skilled in the art will readily appreciate other embodiments of the present application after considering the specification and practicing the invention herein. The present application is intended to cover any variations, uses or adaptations of the present application, which follow the general principles of the present application and include common knowledge or customary technical means in the art that are not invented by the present application.

[0063] It should be understood that the present application is not limited to the exact construction that has been described above and shown in the drawings, and that various modifications and changes may be made without departing from the scope thereof.

Claims

1. A heat dissipation method for a frequency converter, characterized in that: The method comprises the following steps: Real-time collection of the current inverter's movement substrate temperature, internal ambient temperature and input power; Analyze the correlation between the movement substrate temperature and the internal ambient temperature; calculate the ratio of the extreme values ​​of the two data in the same time window; determine whether the slopes of the fitted straight lines of the two data in the same time window have the same sign to determine the determination factor of the time window; reversely fuse the determination factors and ratios calculated in all the same time windows sliding on the two data, and then forwardly fuse the results with the correlation to obtain the heat dissipation defect index of the current inverter; Obtain the extreme points of all calculated heat dissipation defect indexes; in a time window centered on each extreme point, use all corresponding power data and heat dissipation defect indexes as independent variables and dependent variables for straight line fitting, and calculate the mean square error of the fitting straight line; calculate the similarity between all corresponding power data and heat dissipation defect indexes; reversely fuse the similarity of all time windows centered on the extreme point with the mean square error to obtain the difference in thermal radiation efficiency of the inverter; The proportional gain Kp in the PID controller is adjusted according to the difference in heat radiation efficiency to control the heat dissipation intensity of the inverter.

2. The heat dissipation method for a frequency converter according to claim 1, characterized in that: The determination method of the determination factor of the time window is: if the slopes of the fitted straight lines of the two types of data in the same time window have the same sign, the determination factor of the time window is set to a value of 1; otherwise, it is set to a value of 0.

3. The heat dissipation method for a frequency converter according to claim 1, characterized in that: The heat dissipation defect index of the current inverter is recorded as A. ;in, is the normalized function, a is the correlation between the movement substrate temperature and the internal ambient temperature, K is the number of sliding time windows, is the ratio of the extreme difference between the movement substrate temperature and the internal ambient temperature in the kth time window, is the determination factor of the kth time window, Adjust the parameters for the preset denominator.

4. The heat dissipation method for a frequency converter according to claim 3, characterized in that: The sliding method is to use a preset time period as a sliding step and slide the time window in the order of the collection time from small to large.

5. The heat dissipation method for a frequency converter according to claim 1, characterized in that: The difference in heat radiation efficiency of the inverter is recorded as B. ; Where P is the number of time windows centered on the extreme point, is the similarity calculated in the pth time window centered on the extreme point, e is a natural constant, is the mean square error calculated in the pth time window centered on the extreme point.

6. The heat dissipation method for a frequency converter according to claim 5, characterized in that: The extreme value points are obtained from a sequence of all calculated heat dissipation defect indices sorted in chronological order.

7. The heat dissipation method for a frequency converter according to claim 6, characterized in that: The size of the time window constructed with each extreme point as the center does not have the same value relationship as the size of the time window when analyzing the two types of data mentioned above.

8. The heat dissipation method for a frequency converter according to claim 1, characterized in that: The adjustment relationship of proportional gain Kp is: ;in, is the adjusted proportional gain Kp, is the preset adjustment parameter, B is the heat radiation efficiency difference of the inverter; among them, the initial value of Kp is the preset value.

9. The heat dissipation method for a frequency converter according to claim 8, characterized in that: The method for adjusting the proportional gain Kp in the PID controller according to the difference in heat radiation efficiency to control the heat dissipation intensity of the inverter is: The preset integral gain Ki, the initial value of the differential gain Kd and the adjusted proportional gain Kp are used as the input of the PID controller, and the improved PID controller is used to output a control signal, which is used to control the heat dissipation intensity of the inverter heat dissipation system.

10. A heat dissipation system for a frequency converter, comprising a memory, a processor, and a computer program stored in the memory and running on the processor, characterized in that: When the processor executes the computer program, the heat dissipation method for the inverter according to any one of claims 1 to 9 is implemented.

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