Inverter cooling fin temperature control method and system

Abstract

The invention relates to the technical field of inverter heat management, and discloses an inverter cooling fin temperature control method and system, and the method comprises the steps: sampling the temperature of an inverter cooling fin, the environment temperature and the temperature of an inverter box body according to a preset period, and generating an over-temperature warning signal when any one exceeds a corresponding preset alarm threshold value; calculating to obtain an expected temperature value of the cooling fins of the inverter according to the corresponding relation between the real-time environment temperature and the expected temperature value of the cooling fins of the inverter and the corresponding relation between the preset environment temperature and the expected temperature value of the cooling fins of the inverter; a target temperature control interval of the inverter cooling fins is determined based on the expected temperature value of the inverter cooling fins, and according to the size relation between the actual temperature value of the inverter cooling fins and the target temperature control interval, the actual temperature of the inverter cooling fins is made to be within the target temperature control interval by controlling the duty ratio of a fan or the power of an inverter. According to the invention, the inverter can automatically detect the maximum power for operation at different environment temperatures, and the environment adaptability of the inverter is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of inverter thermal management, and in particular to a method and system for controlling the temperature of an inverter heat sink. Background Art

[0002] By adding a fan module inside or outside the inverter, the fan generates airflow to accelerate the heat dissipation of the heat sink and reduce the inverter temperature. This method is currently the most widely used and effective cooling method in the industry. In terms of fan control solutions, there are generally two types of control ideas:

[0003] 1. Adjust the fan speed (duty cycle of the fan) according to the actual power. Generally, a curve of the relationship between power and fan speed is obtained through experiments, and the fan speed is adjusted according to the curve. The advantage of this solution is that no temperature sensor is required, which reduces costs. The disadvantage is that the inverter heat sink temperature is indirectly controlled by the power size, and the power and fan speed curve needs to leave a margin, which is not conducive to the inverter efficiency, and the environmental adaptability (the control effect of the inverter heat sink temperature under different ambient temperatures) is poor. Some optimization solutions add the ambient temperature as a weight value to control the fan speed together with the power to improve the environmental adaptability.

[0004] 2. The temperature of the heat sink is detected by the built-in temperature sensor, and the fan speed is adjusted in real time according to the temperature change. The higher the temperature of the heat sink, the higher the fan speed. The advantage of this solution is that the temperature of the heat sink is directly controlled by monitoring its temperature, which is simple and direct, and there is no problem of environmental adaptability. The disadvantage is that it is difficult to confirm the control coefficient. If the coefficient is too small, the temperature of the heat sink will continue to rise, and the inverter will eventually enter over-temperature load reduction, or even over-temperature failure; if the coefficient is too large, it will also be detrimental to the efficiency of the inverter. In actual development, considering the hardware differences and long-term operation of the inverter, engineers will set the coefficient too large. Based on this solution, the temperature of the heat sink is processed in sections, and different control coefficients are used in different temperature sections, so that the temperature control is more refined, but it also increases the difficulty of determining the control coefficient.

[0005] Therefore, through the above analysis, it can be seen that it is difficult to simultaneously ensure high efficiency of the inverter and control the temperature of the radiator with the existing technology. Summary of the invention

[0006] In view of this, the present invention provides a method and system for controlling the temperature of an inverter heat sink, which solves the problem of how to simultaneously ensure the high efficiency of the inverter and the temperature control of the heat sink.

[0007] In a first aspect, the present invention provides a method for controlling the temperature of an inverter heat sink, the method comprising:

[0008] Sampling the inverter heat sink temperature, the ambient temperature and the inverter box temperature according to a preset period, and generating an over-temperature warning signal when any one of the inverter heat sink temperature, the ambient temperature and the inverter box temperature exceeds the corresponding preset alarm threshold;

[0009] The expected value of the inverter heat sink temperature is calculated using the corresponding relationship between the real-time ambient temperature and the preset ambient temperature and the expected value of the inverter heat sink temperature;

[0010] A target temperature control range of the inverter heat sink is determined based on the expected value of the inverter heat sink temperature, and according to the relationship between the actual value of the inverter heat sink temperature and the target temperature control range, the actual temperature of the inverter heat sink is made to be within the target temperature control range by controlling the fan duty cycle or the inverter power.

[0011] The inverter heat sink temperature control method provided by the embodiment of the present invention calculates the expected value by using the corresponding relationship between the real-time ambient temperature and the preset ambient temperature and the expected value of the inverter heat sink temperature, so that the control target of the heat sink temperature is more reasonable. Under different ambient temperatures, while ensuring that the heat sink temperature is within the target control range, the inverter can self-test the maximum power that can be operated, while improving the environmental adaptability of the inverter.

[0012] The corresponding relationship between the preset ambient temperature and the expected value of the inverter heat sink temperature includes:

[0013] When the ambient temperature is lower than the first temperature, the expected value of the inverter heat sink temperature is the first temperature;

[0014] When the ambient temperature is greater than a second temperature, the expected value of the inverter heat sink temperature is the second temperature;

[0015] When the ambient temperature is greater than or equal to the first temperature and less than the second temperature, there is a positive correlation between the ambient temperature and the expected value of the inverter heat sink temperature.

[0016] In the embodiment of the present invention, when the ambient temperature is lower than the first temperature, the expected value of the inverter heat sink temperature is set to the first temperature, which can ensure that the inverter heat sink has a relatively stable operating temperature in a low temperature environment; when the ambient temperature is greater than or equal to the first temperature and lower than the second temperature, the ambient temperature and the expected value of the inverter heat sink temperature are positively correlated, which can take into account the heat dissipation capacity of the environment. As the ambient temperature increases, the expected value of the heat sink temperature is appropriately increased to adjust the temperature target of the heat sink, which can ensure the normal heat dissipation of the inverter without excessively consuming heat dissipation resources such as fans; when the ambient temperature is higher than the second temperature, the expected value of the inverter heat sink temperature is set to the second temperature, which plays a protective role in a high temperature environment. When the ambient temperature is too high, the heat dissipation difficulty increases sharply. By fixing the expected value of the heat sink temperature at the second temperature, the heat sink temperature can be prevented from increasing unlimitedly with the ambient temperature, thereby preventing the inverter from being damaged due to excessive internal temperature.

[0017] In an optional embodiment, the target temperature control interval is (T ref -T,T ref ), where T ref represents the expected value of the inverter heat sink temperature, T is the preset temperature hysteresis, T∈[2°, 4°].

[0018] The embodiment of the present invention sets the target temperature control interval as the power backload interval, so as to achieve the purpose of the inverter operating power continuously and automatically testing the maximum power that can allow safe operation under the ambient temperature.

[0019] In an optional implementation, based on the relationship between the actual value of the inverter heat sink temperature and the target temperature control interval, controlling the fan duty cycle or the inverter power so that the actual temperature of the inverter heat sink is within the target temperature control interval includes:

[0020] Determine the actual value of the inverter heat sink temperature T h Is it greater than T ref ;

[0021] If the actual value of the inverter heat sink temperature is T h Greater than T ref , then determine the fan duty cycle D out Is it the maximum value? If not, adjust D out Increase to reduce T h , if D out If the inverter power limit value P is already the maximum, then reduce the inverter power limit value P limit , so that T h reduce;

[0022] When the actual value of the inverter heat sink temperature T h In the target temperature control range (Tref -T,T ref ) in the case of increasing the inverter power limit P limit , so that T h rise;

[0023] When the actual value of the inverter heat sink temperature T h Less than T ref -T, determine the fan duty cycle D out Is it the minimum value?

[0024] If not, adjust D out Reduce so that T h Increase, if D out If it is already the minimum, increase the inverter power limit P limit , so that T h Increase.

[0025] The embodiment of the present invention can keep the inverter heat sink temperature within a relatively reasonable range through a series of dynamic control measures based on the relationship between the actual value of the heat sink temperature and the target temperature control range, thereby ensuring that the internal components of the inverter operate in a stable temperature environment, thereby improving the stability and reliability of the inverter system, reducing the occurrence of failures, and extending the service life of the inverter.

[0026] In an optional implementation, a PI controller is used to adjust the duty cycle of the fan, and an output limit of the PI controller is determined according to a duty cycle range of the fan.

[0027] The embodiment of the present invention uses a PI controller to improve the temperature control response speed and accuracy. Different fans have their own operating ranges, including minimum duty cycle and maximum duty cycle. By setting the output limit of the PI controller to match the fan duty cycle range, it can be ensured that the control signal output by the controller is within the range acceptable to the fan.

[0028] In an optional implementation, after the step of controlling the fan duty cycle or the inverter power so that the actual temperature of the inverter heat sink is within the target temperature control range, the method further includes:

[0029] Determine whether the inverter is in grid-connected mode or off-grid mode;

[0030] If the inverter is not in the grid-connected mode and is not in the off-grid mode, the power limit of the inverter is limited to the rated power, the integral of the PI controller is cleared to 0, and the preset system duty cycle is assigned to the duty cycle of the fan;

[0031] If the inverter is in the grid-connected mode or the off-grid mode, the fan duty cycle is adjusted according to the control method of any of the above embodiments.

[0032] In an optional embodiment, the method further comprises: when the inverter heat sink temperature, the ambient temperature and the inverter box temperature are all lower than their respective corresponding preset temperature thresholds, generating an over-temperature clearing signal, wherein each temperature threshold range of the over-temperature clearing signal is lower than each temperature threshold range of the over-temperature warning signal;

[0033] When the over-temperature clearing signal is generated, the inverter switches to standby mode, and performs self-check after receiving the grid-connected or off-grid operation start signal sent by the control end. After the self-check is completed, it enters the grid-connected or off-grid operation mode again, assigns the fan duty cycle to the minimum value, and adjusts the fan duty cycle according to the control method of any of the above-mentioned implementation methods.

[0034] The temperature threshold ranges for clearing over-temperature signals in the embodiments of the present invention are smaller than the temperature threshold ranges for generating over-temperature warning signals because, in actual environments, temperature measurement may be interfered with by a variety of factors, resulting in small fluctuations in temperature readings. If the threshold for clearing over-temperature signals is the same as the threshold for generating over-temperature warning signals, these small temperature fluctuations may cause over-temperature warning signals to appear and disappear frequently, causing the automated monitoring system to frequently trigger unnecessary alarm actions. By setting the threshold for clearing over-temperature signals to be lower, it can be ensured that the over-temperature warning signal is cleared only after the temperature of the device drops to a safer range.

[0035] In a second aspect, the present invention provides an inverter heat sink temperature control system, comprising:

[0036] A temperature monitoring module, used to sample the inverter heat sink temperature, ambient temperature and inverter box temperature according to a preset period, and generate an over-temperature warning signal when any one of the inverter heat sink temperature, ambient temperature and inverter box temperature exceeds the corresponding preset alarm threshold;

[0037] The heat sink temperature expected value calculation module is used to calculate the inverter heat sink temperature expected value by using the real-time ambient temperature and the corresponding relationship between the preset ambient temperature and the inverter heat sink temperature expected value;

[0038] The temperature control module is used to determine the target temperature control range of the inverter heat sink based on the expected value of the inverter heat sink temperature, and according to the relationship between the actual value of the inverter heat sink temperature and the target temperature control range, control the fan duty cycle or the inverter power to make the actual temperature of the inverter heat sink within the target temperature control range.

[0039] In a third aspect, the present invention provides a computer device, comprising: a memory and a processor, the memory and the processor are communicatively connected to each other, computer instructions are stored in the memory, and the processor executes the inverter heat sink temperature control method of the first aspect or any corresponding embodiment thereof by executing the computer instructions.

[0040] In a fourth aspect, the present invention provides a computer-readable storage medium having computer instructions stored thereon, the computer instructions being used to enable a computer to execute the inverter heat sink temperature control method of the first aspect or any corresponding embodiment thereof.

[0041] In a fifth aspect, the present invention provides a computer program product, comprising computer instructions, wherein the computer instructions are used to enable a computer to execute the inverter heat sink temperature control method of the first aspect or any corresponding embodiment thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0043] Figure 1 A schematic flow chart of a method for controlling the temperature of an inverter heat sink according to an embodiment of the present invention;

[0044] Figure 2 According to an embodiment of the present invention, env is the horizontal axis, T xRef Draw points for the vertical axis and draw a dot graph;

[0045] Figure 3 is a correspondence between an ambient temperature and an expected value of an inverter heat sink temperature according to an embodiment of the present invention;

[0046] Figure 4 A schematic diagram of a target temperature control interval and a fan duty cycle or inverter power adjustment method according to an embodiment of the present invention;

[0047] Figure 5 A schematic flow chart of a method for controlling the temperature of an inverter heat sink according to a specific example of an embodiment of the present invention;

[0048] Figure 6 is a temperature control curve diagram of the entire temperature range according to a specific example of an embodiment of the present invention;

[0049] Figure 7is a load reduction curve diagram of the entire temperature range according to a specific example of an embodiment of the present invention;

[0050] Figure 8 is a structural block diagram of an inverter heat sink temperature control system according to an embodiment of the present invention;

[0051] Fig. 9 Schematic diagram of the hardware structure of a computer device according to an embodiment of the present invention. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0053] In order to control the fan to consume relatively less energy, the heat sink temperature is controlled to a reasonable temperature, and the environmental adaptability of the inverter is improved. Under different ambient temperatures, the inverter can self-test the maximum power that can be operated. An embodiment of the present invention provides an inverter heat sink temperature control method embodiment. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described can be executed in a different order than here.

[0054] In this embodiment, a method for controlling the temperature of an inverter heat sink is provided. Figure 1 FIG. 1 is a flow chart of a method for controlling the temperature of an inverter heat sink according to an embodiment of the present invention. Figure 1 As shown, the process includes the following steps:

[0055] S101, sampling the inverter heat sink temperature, ambient temperature and inverter box temperature according to a preset period, and generating an over-temperature warning signal when any one of the inverter heat sink temperature, ambient temperature and inverter box temperature exceeds the corresponding preset alarm threshold.

[0056] Specifically, the heat sink is a key component of the inverter heat dissipation. When the heat sink temperature exceeds the preset alarm threshold, a warning signal is issued to trigger temperature control, which can avoid damage to the electronic components inside the inverter due to overheating; the ambient temperature also has an important impact on the operation of the inverter. When the ambient temperature is too high, even if the inverter works normally, its heat dissipation burden will increase; the cabinet temperature reflects the overall thermal condition inside the inverter. If the cabinet temperature is too high, it means that the heat accumulation inside the inverter has reached a certain level, which may be caused by a variety of reasons such as a failure in the heat dissipation system and abnormal heating of internal components. When any of the three temperature values ​​exceeds the corresponding alarm threshold, a warning is issued in time and the power is stopped or the machine is shut down, which can prevent excessive accumulation of heat in the cabinet, thereby protecting all electronic components in the cabinet.

[0057] Due to the changes in the environment around the inverter, the ambient temperature signal collected by the temperature sensor may be affected by various interferences, such as electromagnetic interference, high-frequency noise, wind and cloud shadows, which may cause fluctuations in the ambient temperature sampling and result in the subsequent expected value of the heat sink temperature T ref Fluctuation, which leads to the inverter power limit P limit The actual power changes continuously, so it is necessary to perform a first-order low-pass filtering on the ambient temperature sample, which can effectively filter out these high-frequency interference components and make the temperature data present a smooth curve that is more in line with the actual change law. In one embodiment, the time constant t=30s is set.

[0058] The embodiment of the present invention updates the temperature value by sampling every second. h Greater than 87℃, box temperature T bo Greater than 89°C, ambient temperature T env When the temperature is greater than 68℃ or less than -27℃, an over-temperature warning signal is generated for example, and at the same time the heat sink temperature T h Less than 72℃, box temperature T bo Less than 72℃, ambient temperature T env When the temperature is less than 63° C. or greater than -25° C., the over-temperature alarm signal is cleared. This is only an example and is not limited thereto.

[0059] In the embodiment of the present invention, the temperature threshold ranges for clearing the over-temperature signal are smaller than the temperature threshold ranges for generating the over-temperature warning signal because in an actual environment, temperature measurement may be interfered by various factors, resulting in small fluctuations in temperature readings. For example, when other heating devices near the inverter are turned on or off, or when ventilation conditions change slightly in an instant, the data collected by the temperature sensor may rise or fall briefly. If the threshold for clearing the over-temperature signal is the same as the threshold for generating the over-temperature warning signal, these small temperature fluctuations may cause the over-temperature warning signal to appear and disappear frequently, causing the automated monitoring system to frequently trigger unnecessary alarm actions. By setting the threshold for clearing the over-temperature signal to be lower, it can be ensured that the over-temperature warning signal is cleared only after the temperature of the device drops to a safer range.

[0060] After generating the over-temperature clearing signal, the inverter switches to the standby mode, and performs a self-check after receiving the grid-connected or off-grid operation start signal sent by the control end. After the self-check is completed, it enters the grid-connected or off-grid operation mode again, assigns the minimum value to the fan duty cycle, and adjusts the fan duty cycle according to the control method provided in the embodiment of the present invention.

[0061] S102, calculating an expected value of the inverter heat sink temperature by using the real-time ambient temperature and a corresponding relationship between the preset ambient temperature and the expected value of the inverter heat sink temperature.

[0062] The embodiment of the present invention triggers temperature control based on an over-temperature warning signal, uses a closed-loop control system to improve the accuracy of the temperature control system, and improves environmental adaptability. ref is the given closed-loop control system, the heat sink temperature T h The sampling is used as feedback quantity, and the loop control uses PI controller to improve the loop response speed, where the expected value of the inverter heat sink temperature T ref By T env If T ref The calculated value is relatively low. In order to control the heat sink to this temperature, the fan duty cycle D out will quickly reach the maximum, resulting in a reduction in the inverter power limit P limit (The inverter power P cannot exceed P limit ), resulting in failure to achieve high power stable output. If the calculated value is relatively large, the inverter will run at high temperature, which is not conducive to the life of the inverter. Therefore, the functional relationship between the ambient temperature and the expected value of the heat sink temperature is very important. The steps for determining the functional relationship between the two in the embodiment of the present invention are as follows:

[0063] 1. Set the temperature of the temperature rise box to 0℃, charge the inverter at rated power, set the fan to operate at maximum speed, and wait for the radiator temperature to stabilize, recorded as T 0Ref1; Set the rated power of the inverter to discharge, set the fan to operate at the maximum speed, and wait for the radiator temperature to stabilize, recorded as T 0Ref2 Considering the temperature margin, T 0Ref =Max(T 0Ref1 ,T 0Ref2 )+1℃.

[0064] 2. Set the temperature of the temperature rise box to 5°C, charge the inverter at rated power, set the fan to operate at maximum speed, and wait for the radiator temperature to stabilize, recorded as T 5Ref1 ; Set the rated power of the inverter to discharge, set the fan to operate at the maximum speed, and wait for the radiator temperature to stabilize, recorded as T 5Ref2 Considering the temperature margin, T 5Ref =Max(T 5Ref1 ,T 5Ref2 )+1℃.

[0065] 3. Similarly, with 5℃ as a span, up to 55℃, the corresponding T xRef . env is the horizontal axis, T xRef Draw points for the vertical axis, and the plot diagram is as follows Figure 2 As shown, the calculation formula for the slope b of the regression line is:

[0066]

[0067] where x i and i are the observation points of the independent and dependent variables, respectively. and are the means of the independent and dependent variables respectively, and Σ represents the sum of all observation points.

[0068] The calculation formula for intercept a is:

[0069]

[0070] where b is the calculated slope.

[0071] In the embodiment of the present invention, a=39.7, b=0.72 are calculated and substituted into the formula to obtain the regression line equation: ref =T env *0.72+39.7.

[0072] In one embodiment, if Figure 3 As shown in the experiment, it is found that when T env When the temperature is less than 12.5℃, T ref Less than 48.3℃. At this temperature, the inverter has no risk of overheating or component damage due to temperature, so it can be limited to T ref Low value; when Tenv When it is greater than 53℃, T ref Greater than 78.3℃, in order to prevent the inverter temperature from being too high and causing it to run at high temperature for a long time, it can be limited to T ref Therefore, T ref The value range is (48.7,78.3).

[0073] Based on the above process, the corresponding relationship between the ambient temperature and the expected value of the inverter heat sink temperature is: when the ambient temperature is less than 12.5°C, the expected value of the inverter heat sink temperature is 48.7°C; when the ambient temperature is greater than or equal to 12.5°C and less than 53°C, there is a positive correlation between the ambient temperature and the expected value of the inverter heat sink temperature. For example, T ref =T env *0.72+39.7; When the ambient temperature is greater than 53℃, the expected value of the inverter heat sink temperature is 78.3℃. This ensures that the inverter heat sink has a relatively stable operating temperature in a low temperature environment. In a medium temperature environment, the ambient temperature and the expected value of the inverter heat sink temperature are positively correlated, which can fully utilize the heat dissipation capacity of the environment. As the ambient temperature rises, the expected value of the heat sink temperature is appropriately increased to adjust the temperature target of the heat sink, which can ensure the normal heat dissipation of the inverter without excessively consuming heat dissipation resources such as fans; in a high temperature environment, the heat sink temperature can be prevented from rising unlimitedly with the ambient temperature, preventing the inverter from being damaged due to excessive internal temperature.

[0074] S103, determining a target temperature control range of the inverter heat sink based on an expected value of the inverter heat sink temperature, and making the actual temperature of the inverter heat sink within the target temperature control range by controlling the fan duty cycle or the inverter power according to the relationship between the actual value of the inverter heat sink temperature and the target temperature control range.

[0075] Specifically, the present invention sets the target temperature control interval (T ref -T,T ref ) is the power backload range, such as Figure 4 As shown, the effect is that when the heat sink temperature T h Down to T ref Below, it will slowly return to the load. When T h Higher than T ref , start adjusting the fan, D out Increase, T h Down to T again ref Below, D out Maintain, power slowly returns, T h Again higher than T ref , D out Increase again, and so on, D out Eventually it increases to D max, and when T h Again higher than T ref , at this time, the power will be reduced. In this way, the inverter operating power will automatically test the maximum power that can be allowed to operate safely at the ambient temperature, and the inverter will be able to operate safely when the set power is greater than P limit The output power is maximized when the temperature is high. The width of this interval is 2 to 4, in degrees Celsius.

[0076] The specific process of the above step S103, which controls the fan duty cycle or the inverter power so that the actual temperature of the inverter heat sink is within the target temperature control range, is as follows:

[0077] a1, determine the actual value of the inverter heat sink temperature T h Is it greater than T ref ;

[0078] a2, if the actual value of the inverter heat sink temperature is T h Greater than T ref , then determine the fan duty cycle D out Is it the maximum value? If not, adjust D out Increase to reduce T h , if D out If the inverter power limit value P is already the maximum, then reduce the inverter power limit value P limit , so that T h reduce;

[0079] a3, when the actual value of the inverter heat sink temperature T h In the target temperature control range (T ref -T,T ref ) in the case of increasing the inverter power limit P limit , so that T h rise;

[0080] a4, when the actual value of the inverter heat sink temperature T h Less than T ref -2, determine the fan duty cycle D out Is it the minimum value?

[0081] a5, if not, adjust D out Reduce so that T h Increase, if D out If it is already the minimum, increase the inverter power limit P limit , so that T h Increase.

[0082] The embodiment of the present invention can keep the inverter heat sink temperature within a relatively reasonable range through the above-mentioned series of dynamic control measures based on the relationship between the actual value of the heat sink temperature and the target temperature control range, thereby ensuring that the internal components of the inverter operate in a stable temperature environment, thereby improving the stability and reliability of the inverter system, reducing the occurrence of failures, and extending the service life of the inverter.

[0083] The embodiment of the present invention uses a PI controller to adjust the duty cycle of the fan. The use of a PI controller can improve the temperature control response speed and accuracy. The mathematical expression of the PI controller is:

[0084]

[0085] Wherein, k represents the sampling number, k = 0, 1, 2, ...; u k Indicates the calculated output value at the kth sampling moment; e k Indicates the input error value at the kth sampling moment; K p Indicates the proportionality coefficient; K i Indicates the integral coefficient. If the deviation is always positive or negative, the integral term of the PI controller will continue to accumulate, so the integral term must be limited, and the output must also be limited. The output limit of the PI controller is determined according to the duty cycle range of the fan. Assuming the duty cycle range of the fan is (300,950), D should be designed. out =625-CtrlOut, CtrlOut is limited to (-325, 325).

[0086] The inverter heat sink temperature control method provided by the embodiment of the present invention calculates the expected value by using the corresponding relationship between the real-time ambient temperature and the preset ambient temperature and the expected value of the inverter heat sink temperature, so that the control target of the heat sink temperature is more reasonable. Under different ambient temperatures, while ensuring that the heat sink temperature is within the target control range, the inverter can self-test the maximum power that can be operated, thereby improving the environmental adaptability of the inverter, and by using a PI controller, the temperature control response speed and accuracy are improved.

[0087] After the step of controlling the fan duty cycle or the inverter power so that the actual temperature of the inverter heat sink is within the target temperature control range, the embodiment of the present invention further includes:

[0088] S104, determining whether the inverter is in grid-connected mode or off-grid mode;

[0089] S105, if the inverter is not in the grid-connected mode and is not in the off-grid mode, limiting the power limit of the inverter to the rated power, clearing the integral of the PI controller to 0, and assigning a preset system duty cycle to the duty cycle of the fan;

[0090] S106: If the inverter is in the grid-connected mode or the off-grid mode, the fan duty cycle is adjusted according to the above control method.

[0091] It should be noted that if the inverter is not in grid-connected mode or off-grid mode, it means that the inverter is in burning mode, fault mode or standby mode, which means that the inverter is not running, so the heat sink temperature does not need to be controlled, and the integral of the PI controller needs to be cleared to 0.

[0092] Since the fan speed is determined by the duty cycle, the heat generated by the inverter can be effectively dissipated under appropriate conditions. Therefore, after the heat sink temperature is controlled in the target temperature control range, the system PWM is assigned to the fan duty cycle, which can provide a relatively stable heat dissipation environment for the inverter and continue to update the various monitored temperatures for continuous temperature control.

[0093] In a specific embodiment, the flow chart of the inverter heat sink temperature control method provided by the embodiment of the present invention is as follows: Figure 5 As shown, the inverter heat sink temperature, ambient temperature and inverter box temperature are updated once per second. When sampling the ambient temperature, a first-order low-pass filter is used to reduce fluctuations, and an over-temperature warning is issued and cleared according to the set temperature threshold. The expected value of the heat sink temperature is calculated based on the real-time ambient temperature. If it is over-rated, that is, over-rated operation, T ref The calculation of T needs to be appropriately increased. ref =P / Pn*(T env *0.72+39.7), so that the loop can easily control the heat sink temperature and not enter load reduction too quickly. By comparing the real-time heat sink temperature with the expected value, the fan duty cycle or inverter power is adjusted to make the actual temperature of the inverter heat sink within the target temperature control range. Then, the fan duty cycle is updated according to the state of the inverter. The full temperature range temperature control curve obtained in the process is as follows: Figure 6 As shown, the full temperature range load reduction curve is as follows Figure 7 As shown, it can be seen that the radiator temperature can be well controlled within the target control range. At the same time, the inverter can self-test the maximum operating power, achieving environmental adaptability and ensuring the high efficiency of the inverter and radiator temperature control.

[0094] In this embodiment, an inverter heat sink temperature control system is also provided, which is used to implement the above embodiments and preferred implementations, and will not be repeated here. As used below, the term "module" can implement a combination of software and / or hardware for a predetermined function. Although the system described in the following embodiments is preferably implemented in software, the implementation of hardware, or a combination of software and hardware, is also possible and conceivable.

[0095] This embodiment provides an inverter heat sink temperature control system. Figure 8 As shown, including:

[0096] The temperature monitoring module 801 is used to sample the inverter heat sink temperature, the ambient temperature and the inverter box temperature according to a preset period, and generate an over-temperature warning signal when any one of the inverter heat sink temperature, the ambient temperature and the inverter box temperature exceeds the corresponding preset alarm threshold;

[0097] The heat sink temperature expected value calculation module 802 is used to calculate the inverter heat sink temperature expected value by using the real-time ambient temperature and the corresponding relationship between the preset ambient temperature and the inverter heat sink temperature expected value;

[0098] The temperature control module 803 is used to determine the target temperature control range of the inverter heat sink based on the expected value of the inverter heat sink temperature, and according to the relationship between the actual value of the inverter heat sink temperature and the target temperature control range, control the fan duty cycle or the inverter power to make the actual temperature of the inverter heat sink within the target temperature control range.

[0099] In some optional implementations, the correspondence between the preset ambient temperature and the expected value of the inverter heat sink temperature in the heat sink temperature expected value calculation module 802 includes:

[0100] When the ambient temperature is lower than the first temperature, the expected value of the inverter heat sink temperature is the first temperature; when the ambient temperature is greater than or equal to the first temperature and lower than the second temperature, there is a positive correlation between the ambient temperature and the expected value of the inverter heat sink temperature; when the ambient temperature is greater than the second temperature, the expected value of the inverter heat sink temperature is the second temperature.

[0101] In some optional implementations, the target temperature control interval in the heat sink temperature expected value calculation module 802 is (T ref -T,T ref ), where T ref represents the expected value of the inverter heat sink temperature, T is the preset temperature hysteresis, T∈[2°, 4°].

[0102] In some optional implementations, the temperature control module 803 controls the fan duty cycle or the inverter power according to the relationship between the actual value of the inverter heat sink temperature and the target temperature control interval so that the actual temperature of the inverter heat sink is within the target temperature control interval, including:

[0103] Determine the actual value of the inverter heat sink temperature T h Is it greater than T ref ;

[0104] If the actual value of the inverter heat sink temperature is T hGreater than T ref , then determine the fan duty cycle D out Is it the maximum value? If not, adjust D out Increase to reduce T h , if D out If the inverter power limit value P is already the maximum, then reduce the inverter power limit value P limit , so that T h reduce;

[0105] When the actual value of the inverter heat sink temperature T h In the target temperature control range (T ref -2,T ref ) in the case of increasing the inverter power limit P limit , so that T h rise;

[0106] When the actual value of the inverter heat sink temperature T h Less than T ref -T, determine the fan duty cycle D out Is it the minimum value?

[0107] If not, adjust D out Reduce so that T h Increase, if D out If it is already the minimum, increase the inverter power limit P limit , so that T h Increase.

[0108] In some optional implementations, a PI controller is used to adjust the duty cycle of the fan, and an output limit of the PI controller is determined according to a duty cycle range of the fan.

[0109] In some optional embodiments, the system further comprises: a duty cycle updating module, configured to determine whether the inverter is in a grid-connected mode or an off-grid mode;

[0110] If the inverter is not in the grid-connected mode and is not in the off-grid mode, the power limit of the inverter is limited to the rated power, the integral of the PI controller is cleared to 0, and the preset system duty cycle is assigned to the duty cycle of the fan;

[0111] If the inverter is in the grid-connected mode or the off-grid mode, the fan duty cycle is adjusted according to the control method of any of the above embodiments.

[0112] In an optional embodiment, the system further includes:

[0113] An over-temperature clearing signal generating module is used to generate an over-temperature clearing signal when the inverter heat sink temperature, the ambient temperature and the inverter box temperature are all lower than their corresponding preset temperature thresholds, and each temperature threshold range of the over-temperature clearing signal is lower than each temperature threshold range of the over-temperature warning signal;

[0114] The restart module is used to switch the inverter to standby mode after generating a clear overtemperature signal, and perform self-check after receiving a grid-connected or off-grid operation start signal sent by the control end. After the self-check is completed, the inverter enters the grid-connected or off-grid operation mode again, assigns a minimum value to the fan duty cycle, and adjusts the fan duty cycle according to the control method of any of the above-mentioned implementation methods.

[0115] The further functional description of each of the above modules and units is the same as that of the above corresponding embodiments and will not be repeated here.

[0116] The inverter heat sink temperature control system in this embodiment is presented in the form of a functional unit, where the unit refers to an ASIC (Application Specific Integrated Circuit) circuit, a processor and memory that executes one or more software or fixed programs, and / or other devices that can provide the above functions.

[0117] The embodiment of the present invention also provides a computer device having the above Figure 8 The inverter heat sink temperature control system shown.

[0118] See also Fig. 9 , Fig. 9 is a schematic diagram of the structure of a computer device provided by an optional embodiment of the present invention, such as Fig. 9 As shown, the computer device includes: one or more processors 10, a memory 20, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components are connected to each other using different buses for communication, and can be installed on a common mainboard or installed in other ways as needed. The processor can process the instructions executed in the computer device, including instructions stored in or on the memory to display the graphical information of the GUI on an external input / output device (such as, a display device coupled to the interface). In some optional embodiments, if necessary, multiple processors and / or multiple buses can be used together with multiple memories and multiple memories. Similarly, multiple computer devices can be connected, and each device provides some necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). Fig. 9 A processor 10 is taken as an example.

[0119] The processor 10 may be a central processing unit, a network processor or a combination thereof. The processor 10 may further include a hardware chip. The hardware chip may be a dedicated integrated circuit, a programmable logic device or a combination thereof. The programmable logic device may be a complex programmable logic device, a field programmable gate array, a general purpose array logic or any combination thereof.

[0120] The memory 20 stores instructions executable by at least one processor 10, so that at least one processor 10 executes the method shown in the above embodiment.

[0121] The memory 20 may include a program storage area and a data storage area, wherein the program storage area may store an operating system, an application required for at least one function; the data storage area may store data created according to the use of the computer device, etc. In addition, the memory 20 may include a high-speed random access memory, and may also include a non-transient memory, such as at least one disk storage device, a flash memory device, or other non-transient solid-state storage device. In some optional embodiments, the memory 20 may optionally include a memory remotely arranged relative to the processor 10, and these remote memories may be connected to the computer device via a network. Examples of the above-mentioned network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and combinations thereof.

[0122] The memory 20 may include a volatile memory, such as a random access memory; the memory may also include a non-volatile memory, such as a flash memory, a hard disk or a solid state drive; the memory 20 may also include a combination of the above types of memory.

[0123] The computer device further comprises a communication interface 30 for the computer device to communicate with other devices or a communication network.

[0124] The embodiment of the present invention also provides a computer-readable storage medium. The method according to the embodiment of the present invention can be implemented in hardware, firmware, or can be implemented as a computer code that can be recorded in a storage medium, or can be implemented as a computer code that is originally stored in a remote storage medium or a non-temporary machine-readable storage medium and will be stored in a local storage medium through a network download, so that the method described herein can be stored in such software processing on a storage medium using a general-purpose computer, a dedicated processor, or programmable or dedicated hardware. Among them, the storage medium can be a magnetic disk, an optical disk, a read-only storage memory, a random access memory, a flash memory, a hard disk or a solid-state hard disk, etc.; further, the storage medium can also include a combination of the above types of memories. It can be understood that a computer, a processor, a microprocessor central control system or programmable hardware includes a storage component that can store or receive software or computer code. When the software or computer code is accessed and executed by a computer, a processor or hardware, the method shown in the above embodiment is implemented.

[0125] A part of the present invention may be applied as a computer program product, such as a computer program instruction, which, when executed by a computer, can call or provide the method and / or technical solution according to the present invention through the operation of the computer. Those skilled in the art should understand that the existence of the computer program instruction in a computer-readable medium includes, but is not limited to, a source file, an executable file, an installation package file, etc., and accordingly, the way in which the computer program instruction is executed by the computer includes, but is not limited to: the computer directly executes the instruction, or the computer compiles the instruction and then executes the corresponding compiled program, or the computer reads and executes the instruction, or the computer reads and installs the instruction and then executes the corresponding installed program. Here, the computer-readable medium may be any available computer-readable storage medium or communication medium accessible to the computer.

[0126] Although the embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art may make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations are all within the scope defined by the appended claims.

Claims

1. A method for controlling the temperature of an inverter heat sink, characterized in that: include: Sampling the inverter heat sink temperature, the ambient temperature and the inverter box temperature according to a preset period, and generating an over-temperature warning signal when any one of the inverter heat sink temperature, the ambient temperature and the inverter box temperature exceeds the corresponding preset alarm threshold; The expected value of the inverter heat sink temperature is calculated using the corresponding relationship between the real-time ambient temperature and the preset ambient temperature and the expected value of the inverter heat sink temperature; A target temperature control range of the inverter heat sink is determined based on the expected value of the inverter heat sink temperature, and according to the relationship between the actual value of the inverter heat sink temperature and the target temperature control range, the actual temperature of the inverter heat sink is made to be within the target temperature control range by controlling the fan duty cycle or the inverter power.

2. The method according to claim 1, characterized in that The corresponding relationship between the preset ambient temperature and the expected value of the inverter heat sink temperature includes: When the ambient temperature is lower than the first temperature, the expected value of the inverter heat sink temperature is the first temperature; When the ambient temperature is greater than a second temperature, the expected value of the inverter heat sink temperature is the second temperature; When the ambient temperature is greater than or equal to the first temperature and less than the second temperature, there is a positive correlation between the ambient temperature and the expected value of the inverter heat sink temperature.

3. The method according to claim 1 or 2, characterized in that: The target temperature control interval is (T ref -T,T ref ), where T ref represents the expected value of the inverter heat sink temperature, T is the preset temperature hysteresis, T∈[2°, 4°].

4. The method according to claim 1, characterized in that: Based on the relationship between the actual value of the inverter heat sink temperature and the target temperature control interval, controlling the fan duty cycle or the inverter power so that the actual temperature of the inverter heat sink is within the target temperature control interval includes: Determine the actual value of the inverter heat sink temperature T h Is it greater than T ref ; If the actual value of the inverter heat sink temperature is T h Greater than T ref , then determine the fan duty cycle D out Is it the maximum value? If not, adjust D out Increase to reduce T h , if D out If it is already the maximum, reduce the inverter power limit P limit , so that T h reduce; When the actual value of the inverter heat sink temperature T h In the target temperature control range (T ref -T,T ref ) in the case of increasing the inverter power limit P limit , so that T h rise; When the actual value of the inverter heat sink temperature T h Less than T ref -T, determine the fan duty cycle D out Is it the minimum value? If not, adjust D out Reduce so that T h Increase, if D out If it is already the minimum, increase the inverter power limit P limit , so that T h Increase.

5. The method according to claim 4, characterized in that The duty cycle of the fan is adjusted by using a PI controller, and the output limit of the PI controller is determined according to the duty cycle range of the fan.

6. The method according to claim 4, characterized in that After the step of controlling the fan duty cycle or the inverter power so that the actual temperature of the inverter heat sink is within the target temperature control range, the method further includes: Determine whether the inverter is in grid-connected mode or in off-grid mode; If the inverter is not in the grid-connected mode and is not in the off-grid mode, the power limit of the inverter is limited to the rated power, the integral of the PI controller is cleared to 0, and the preset system duty cycle is assigned to the duty cycle of the fan; If the inverter is in the grid-connected mode or the off-grid mode, the fan duty cycle is adjusted according to the control method according to any one of claims 1 to 5.

7. The method according to claim 6, characterized in that Also includes: When the inverter heat sink temperature, the ambient temperature and the inverter box temperature are all lower than their corresponding preset temperature thresholds, an over-temperature clearing signal is generated, and each temperature threshold range of the over-temperature clearing signal is lower than each temperature threshold range of the over-temperature warning signal; When the over-temperature clearing signal is generated, the inverter switches to standby mode, and performs self-check after receiving the grid-connected or off-grid operation start signal sent by the control end. After the self-check is completed, it enters the grid-connected or off-grid operation mode again, assigns the minimum value to the fan duty cycle, and adjusts the fan duty cycle according to any control method described in claims 1-5.

8. An inverter heat sink temperature control system, characterized in that: include: A temperature monitoring module, used to sample the inverter heat sink temperature, ambient temperature and inverter box temperature according to a preset period, and generate an over-temperature warning signal when any one of the inverter heat sink temperature, ambient temperature and inverter box temperature exceeds the corresponding preset alarm threshold; The heat sink temperature expected value calculation module is used to calculate the inverter heat sink temperature expected value by using the real-time ambient temperature and the corresponding relationship between the preset ambient temperature and the inverter heat sink temperature expected value; The temperature control module is used to determine the target temperature control range of the inverter heat sink based on the expected value of the inverter heat sink temperature, and according to the relationship between the actual value of the inverter heat sink temperature and the target temperature control range, control the fan duty cycle or the inverter power to make the actual temperature of the inverter heat sink within the target temperature control range.

9. A computer device, characterized in that: include: A memory and a processor, wherein the memory and the processor are communicatively connected to each other, the memory stores computer instructions, and the processor executes the inverter heat sink temperature control method according to any one of claims 1 to 7 by executing the computer instructions.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores computer instructions, and the computer instructions are used to enable a computer to execute the inverter heat sink temperature control method according to any one of claims 1 to 7.

11. A computer program product, characterized in that The method comprises computer instructions, wherein the computer instructions are used to enable a computer to execute the inverter heat sink temperature control method according to any one of claims 1 to 7.

Images