Temperature multi-gear self-learning control method and system of PTC (Positive Temperature Coefficient) liquid heater

Abstract

The invention is suitable for the technical field of new energy vehicle battery or cabin heating, and provides a temperature multi-gear self-learning control method and system for a PTC liquid heater, and the method comprises the steps: obtaining the real-time water outlet temperature of the PTC liquid heater when the PTC high-pressure liquid heater enters a constant-temperature mode and the target temperature in PTC message information is kept unchanged, and obtaining the real-time water outlet temperature of the PTC liquid heater according to the real-time water outlet temperature of the PTC liquid heater; the relation between the real-time outlet water temperature and the target temperature is determined; based on the relation between the real-time outlet water temperature and the target temperature, the optimal power gear of the PTC liquid heater is determined; the optimal power gear represents the on-off condition of the insulated bipolar transistor corresponding to each group of PTC. According to the control method, the problem of frequent start and stop caused by too large temperature deviation in a traditional control method can be avoided, the switching frequency of the heater is reduced, the optimal working gear can be quickly selected during constant temperature control, and the effects that an IGBT in the PTC high-pressure liquid heater only needs passive heat dissipation and the appearance of the heater is not limited are achieved.

Description

Technical Field

[0001] This application belongs to the technical field of new energy vehicle battery or cockpit heating, and particularly relates to a temperature multi-gear self-learning control method and system for a PTC liquid heater. Background Art

[0002] With the urgent global demand for environmental protection and energy transformation, electric vehicles (EVs) have become the stars in the future transportation field. However, in cold climates, the endurance and battery performance of electric vehicles face severe challenges.

[0003] Currently, PTC high-voltage liquid heaters are widely used in the battery thermal management system and cockpit air-conditioning heating system of new energy pure electric vehicles (Battery Electric Vehicle, BEV), providing a strong guarantee for the safe operation and comfortable driving of new energy vehicles. The control methods of positive temperature coefficient (PTC) high-voltage liquid heaters are mainly divided into stepless constant temperature regulation and power gear control. Stepless constant temperature regulation requires a pulse width modulation circuit (Pulse Width Modulation, PWM) to control the power device insulated gate bipolar transistor (Insulate-Gate Bipolar Transistor, IGBT) output. Therefore, the IGBT needs active heat dissipation, which limits the shape of the heater; while power gear control has limited application scenarios due to its inability to achieve constant temperature control or poor constant temperature control effect.

[0004] Existing new energy vehicle models all use PTC with a power of 3KW - 20KW to heat and warm the high-voltage power battery and the passenger compartment. Since the performance of the high-voltage power battery of new energy vehicles is very sensitive to the working environment temperature, the general safe working temperature range is -10 to 50°C, and the best working temperature range is 20 to 30°C. Therefore, there are strict requirements for the inlet water temperature of the battery pack. The traditional power control type PTC stops working immediately after the outlet water temperature reaches the target temperature, and the PTC will restart when the temperature drops to a certain level. Throughout the heating process, the PTC will start and stop frequently, resulting in too long heating time and large temperature fluctuations, and cannot well meet the heating requirements of electric vehicles. Summary of the Invention

[0005] To overcome the problems existing in the related technologies, the embodiments of this application provide a temperature multi-gear self-learning control method and system for a PTC liquid heater, which can solve the problems of frequent start and stop of the PTC, resulting in too long heating time and large temperature fluctuations.

[0006] This application is implemented through the following technical solutions:

[0007] In a first aspect, an embodiment of the present application provides a temperature multi-gear self-learning control method for a PTC liquid heater, where the on / off of each group of PTCs in the PTC liquid heater is controlled by at least one IGBT; the method includes:

[0008] When the PTC high-pressure liquid heater enters the constant temperature mode and the target temperature in the PTC message information remains unchanged, obtain the real-time outlet water temperature of the PTC liquid heater, and determine the relationship between the real-time outlet water temperature and the target temperature;

[0009] Based on the relationship between the real-time outlet water temperature and the target temperature, determine the optimal power gear of the PTC liquid heater; the optimal power gear characterizes the on / off conditions of the insulated bipolar transistors corresponding to each group of PTCs.

[0010] In a possible implementation manner of the first aspect, the PTC message information includes the maximum power gear;

[0011] Based on the relationship between the real-time outlet water temperature and the target temperature, determining the optimal power gear of the PTC liquid heater includes:

[0012] When the relationship between the real-time outlet water temperature and the target temperature meets the first preset condition, control the PTC liquid heater to stop heating; the first preset condition is: the real-time outlet water temperature is greater than the sum of the target temperature and the preset floating amount;

[0013] When the relationship between the real-time outlet water temperature and the target temperature meets the second preset condition, control the PTC high-pressure liquid heater to operate at the maximum power gear; the second preset condition is: the real-time outlet water temperature is less than the target temperature;

[0014] When the relationship between the real-time outlet water temperature and the target temperature meets the third preset condition, query whether there is historical gear data corresponding to the target temperature in the self-learning database. If it exists, execute the experience execution program of the self-learning database to lock the optimal power gear corresponding to the target temperature. If it does not exist, execute the standard program for finding the optimal gear to find the optimal power gear; the third preset condition is: the real-time outlet water temperature is greater than or equal to the target temperature and less than or equal to the sum of the target temperature and the preset floating amount.

[0015] In a possible implementation manner of the first aspect, the historical gear data corresponding to the target temperature in the self-learning database includes the historical optimal power gear corresponding to the target temperature;

[0016] Executing the experience execution program of the self-learning database to lock the optimal power gear corresponding to the target temperature includes:

[0017] Obtain the historical optimal power gear;

[0018] If the historical optimal power level is less than or equal to the maximum power level, downshift to verify the rationality of the historical optimal power level, and based on the result of the downshift verification, lock the optimal power level corresponding to the target temperature; if the historical optimal power level is greater than the maximum power level, execute the standard procedure for finding the optimal gear to find the optimal power level.

[0019] In a possible implementation manner of the first aspect, executing the standard procedure for finding the optimal gear to find the optimal power level includes:

[0020] Control the PTC high-pressure liquid heater to start operating at the minimum power level and heat to the target temperature;

[0021] Control the PTC high-pressure liquid heater to upshift and heat on the basis of the minimum power level until the real-time water outlet temperature meets the second fixed condition; the second fixed condition includes that the real-time water outlet temperature remains between the difference between the target temperature and the preset floating amount and the sum of the target temperature and the preset floating amount for more than the preset time, or the real-time water outlet temperature is greater than the sum of the target temperature and the preset floating amount;

[0022] Take the current power level that meets the second fixed condition as the optimal power level.

[0023] In a possible implementation manner of the first aspect, after executing the standard procedure for finding the optimal gear to find the optimal power level, the temperature multi-gear self-learning control method of the PTC liquid heater further includes:

[0024] Store the optimal power level and the target temperature corresponding to the optimal power level in the self-learning database.

[0025] In a possible implementation manner of the first aspect, downshift to verify the rationality of the historical optimal power level, and based on the result of the downshift verification, lock the optimal power level corresponding to the target temperature, including:

[0026] Control the PTC high-pressure liquid heater to downshift and heat by one gear on the basis of the historical optimal power level. If the real-time water outlet temperature does not meet the first fixed condition at this time, heat at the historical optimal power level again. If the real-time water outlet temperature meets the first fixed condition, the result of the downshift verification is reasonable; the first fixed condition includes that the real-time water outlet temperature remains between the difference between the target temperature and the preset floating amount and the sum of the target temperature and the preset floating amount for more than the preset time, or the real-time water outlet temperature is greater than the sum of the target temperature and the preset floating amount;

[0027] If the real-time water outlet temperature is less than or equal to the difference between the target temperature and the preset floating amount at this time, the result of the downshift verification is unreasonable; perform an upshift operation until the real-time water outlet temperature meets the first fixed condition;

[0028] Lock the optimal power level corresponding to the target temperature for the current power level that meets the first fixed condition.

[0029] In a possible implementation of the first aspect, before determining the optimal power level of the PTC liquid heater, it further includes:

[0030] Based on the target power of the PTC liquid heater required by the user, determine multiple power levels;

[0031] Based on the multiple power levels, determine combinations of different levels; the combinations of different levels are used to control the on / off of insulated bipolar transistors to achieve the maximum number of levels.

[0032] In a possible implementation of the first aspect, based on the target power of the PTC liquid heater required by the user, determining multiple power levels includes:

[0033] Obtain the unit power of the PTC liquid heater;

[0034] Based on the target power of the PTC liquid heater required by the user and the unit power, determine the supplementary power;

[0035] Based on the supplementary power and the unit power, determine multiple power levels.

[0036] In a possible implementation of the first aspect, the multiple power levels are expressed as:

[0037] P(N) = N n+1 P left +(N n 2 n +N n-1 2 n-1 ...+N 0 2 0 )P unit

[0038] Wherein, P(N) is the power of the Nth level; N n+1 、N n 、N n-1 ...N 0 are Boolean coefficients; P left is the supplementary power; P unit is the unit power.

[0039] In the second aspect, the present application provides a temperature multi-level self-learning control system for a PTC liquid heater, which is used to execute the temperature multi-level self-learning control method of the PTC liquid heater as in the first aspect.

[0040] The beneficial effects of the embodiments of the present application compared with the prior art are:

[0041] In the embodiments of the present application, through the multi-gear self-learning control subroutine, the power gear is dynamically adjusted according to the relationship between the real-time outlet water temperature and the target temperature, avoiding the problem of frequent start and stop caused by excessive temperature deviation in the traditional control method, reducing the switching times of the heater, and enabling the rapid selection of the optimal working gear during constant temperature control, achieving the effect that the IGBT in the PTC high-pressure liquid heater only needs passive heat dissipation and the shape of the heater is not limited. The constant temperature effect is better than that of the traditional power control type heater, and the service life of the equipment is extended. And based on the dynamic adjustment strategy of real-time temperature feedback and target temperature, it can maintain the set temperature more accurately, avoid frequently triggering heating or stopping heating due to excessive temperature deviation, so as to realize the two control functions of power gear and constant temperature.

[0042] It should be understood that the above general description and the following detailed description are only exemplary and explanatory, and cannot limit this specification. Brief Description of the Drawings

[0043] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for use in the embodiments or the description of the prior art. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0044] Figure 1 It is a schematic flow chart of the temperature multi-gear self-learning control system of the PTC liquid heater provided by an embodiment of the present application;

[0045] Figure 2 It is a schematic logic diagram of the temperature multi-gear self-learning control subroutine provided by an embodiment of the present application;

[0046] Figure 3 It is a schematic structural diagram of the controller provided by an embodiment of the present application. Detailed Embodiments

[0047] In the following description, for the purpose of illustration rather than limitation, specific details such as specific system structures and technologies are presented in order to thoroughly understand the embodiments of the present application. However, those skilled in the art should clearly understand that the present application can also be implemented in other embodiments without these specific details. In other cases, the detailed descriptions of well-known systems, devices, circuits, and methods are omitted to avoid unnecessary details from interfering with the description of the present application.

[0048] It should be understood that, as used in the specification of this application and the appended claims, the term "comprising" indicates the presence of the described features, wholes, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0049] It should also be understood that the term "and / or" used in the specification of this application and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations.

[0050] As used in the specification of this application and the appended claims, the term "if" can be interpreted as "when", "once", "in response to determining", or "in response to detecting" depending on the context. Similarly, the phrases "if determined" or "if [the described condition or event] is detected" can be interpreted as meaning "once determined", "in response to determining", "once [the described condition or event] is detected", or "in response to detecting [the described condition or event]" depending on the context.

[0051] In addition, in the description of the specification of this application and the appended claims, the terms "first", "second", "third", etc. are only used for distinguishing descriptions and cannot be understood as indicating or implying relative importance.

[0052] Reference to "one embodiment" or "some embodiments" or the like described in the specification of this application means that a specific feature, structure, or characteristic described in connection with that embodiment is included in one or more embodiments of this application. Thus, statements such as "in one embodiment", "in some embodiments", "in other some embodiments", "in still other embodiments", etc. that appear in different places in this specification do not necessarily all refer to the same embodiment, but mean "one or more but not all embodiments", unless otherwise specifically emphasized in other ways. The terms "comprising", "including", "having", and their variants all mean "including but not limited to", unless otherwise specifically emphasized in other ways.

[0053] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0054] Figure 1 is a schematic flow chart of a temperature multi - gear self - learning control method for a PTC liquid heater provided by an embodiment of this application. Referring to Figure 1 , the detailed description of the temperature multi - gear self - learning control method for the PTC liquid heater is as follows:

[0055] The embodiment of the present application provides a temperature multi - gear self - learning control method for a PTC liquid heater. In the PTC liquid heater, the on - off of each group of PTCs is controlled by at least one IGBT. The method includes:

[0056] Step 101, when the PTC high - pressure liquid heater enters the constant - temperature mode and the target temperature in the PTC message information remains unchanged, obtain the real - time outlet water temperature of the PTC liquid heater, and determine the relationship between the real - time outlet water temperature and the target temperature.

[0057] Exemplarily, when the PTC high - pressure liquid heater enters the constant - temperature mode, that is, the outlet water temperature of the PTC high - pressure liquid heater is stabilized near the set value, the sensor will continuously monitor the change of the outlet water temperature. Once there is a trend of temperature increase or decrease, the control system will quickly respond. If the temperature starts to be higher than the set value, the PTC element will automatically reduce the power to reduce heat generation; on the contrary, if the temperature is lower than the set value, the PTC element will increase the power to increase the heating speed to ensure that the liquid is always in a suitable constant - temperature state. This constant - temperature mode has important applications in many fields. For example, in the thermal management system of a vehicle, it heats the coolant in the vehicle to ensure that the engine can quickly reach the optimal working temperature in cold weather, and at the same time provides a stable heat source for the heating equipment in the vehicle to improve the comfort of the driver and passengers.

[0058] Step 102, based on the relationship between the real - time outlet water temperature and the target temperature, determine the optimal power gear of the PTC liquid heater.

[0059] Among them, the optimal power gear characterizes the on - off situation of the insulated bipolar transistors corresponding to each group of PTCs.

[0060] Since the on - off of each group of PTCs in the PTC liquid heater is controlled by at least one IGBT, there are multiple combinations of IGBT on - off, resulting in different powers. According to the relationship between the real - time outlet water temperature and the target temperature, the most suitable power is selected. Different combinations of IGBT on - off form different power gears. Therefore, by determining the optimal power gear of the PTC liquid heater, the PTC liquid heater can raise the water temperature close to the target temperature and avoid the situation where the water temperature far exceeds the target temperature, resulting in frequent on - off switching of IGBTs, leading to overheating or other failures.

[0061] In this embodiment, through a multi-gear self-learning control method, the power gear is dynamically adjusted according to the relationship between the real-time outlet water temperature and the target temperature, avoiding the problem of frequent start and stop caused by excessive temperature deviation in the traditional control method, reducing the switching times of the heater, quickly selecting the optimal working gear during constant temperature control, achieving the effect that the IGBT in the PTC high-pressure liquid heater only needs passive heat dissipation and the shape of the heater is not limited, and the constant temperature effect is better than that of the traditional power control type heater, prolonging the service life of the equipment. And based on the dynamic adjustment strategy of real-time temperature feedback and target temperature, it can maintain the set temperature more accurately, avoid frequent triggering of heating or stopping heating due to excessive temperature deviation, and achieve two control functions of power gear and constant temperature.

[0062] In one embodiment, before determining the optimal power gear of the PTC liquid heater, the temperature multi-gear self-learning control method of the PTC liquid heater further includes:

[0063] Based on the target power of the PTC liquid heater required by the user, determine multiple power gears. Based on the multiple power gears, determine combinations of different gears; the combinations of different gears are used to control the on and off of the insulated bipolar transistor to achieve the maximum number of gears.

[0064] Exemplarily, based on the target power of the PTC liquid heater required by the user, determining multiple power gears includes:

[0065] First, obtain the unit power P of the PTC liquid heater unit .

[0066] The unit power of the PTC liquid heater can be comprehensively calculated based on customer power requirements, structural limitations, IGBT selection and quantity.

[0067] Next, based on the target power and unit power of the PTC liquid heater required by the user, determine the supplementary power.

[0068] Exemplarily, the target power P of the PTC liquid heater required by the user total can be expressed as:

[0069] P total = P left +(2 n +2 n-1 +...+2 0 )P unit

[0070] P left is the supplementary power, so the supplementary power can be determined through the above formula. 2 n 2 n-1 ...2 0is a coefficient, and n is a non - negative integer, which can be preset according to the number of IGBTs. Among them, the supplementary power P left is actually the target power P required by the customer total is the remainder when it cannot be evenly divided by the unit power, and it needs to satisfy P left ≤2 n P unit .

[0071] Determine multiple power levels based on the supplementary power and the unit power.

[0072] Exemplarily, 2 0 P unit , 2 1 P unit ,..., 2 n P unit , P left correspond to different power - level groupings, and they can be arbitrarily combined into different power levels. The multiple power levels can be expressed as:

[0073] P(i) = i n+1 P left +(i n 2 n +i n-1 2 n-1 ...+i 0 2 0 )P unit

[0074] Among them, P(i) is the power of the i - th level, i = 0, 1, 2,..., N; N is the number of power - level groupings, then P(N) is the power of the maximum level; i n+1 , i n , i n-1 ...i 0 are Boolean coefficients, taking values of 0 or 1. Each Boolean coefficient corresponds to a group of IGBTs. A group of IGBTs includes at least one IGBT. These coefficients determine the on - off of the PTC heating pack controlled by one or more IGBTs. For example, if i n =1, then turn on the IGBT corresponding to 2 n P unit power, and the PTC heating pack controlled is turned on. If i n =0, then turn off the IGBT corresponding to 2 n P unit power, and the PTC heating pack controlled is turned off; P left is the supplementary power; P unit is the unit power.

[0075] N and i n+1 i n i n-1 ...i0 The relationship is: 0d N = 0b i n+1 i n i n-1 ...i 0 ; 0d represents decimal, 0b represents binary, and convert the decimal N to the binary i n+1 i n i n-1 ...i 0 。i n+1 i n i n-1 ...i 0 is the binary coefficient of N.

[0076]

[0077] Among them, P left %P unit represents P left and P unit The result of dividing the two numbers is equal to P left and P unit The remainder after dividing the two numbers. In the above formula, P total 、P left 、P unit all use the design values without considering the tolerance.

[0078] In this embodiment, before selecting the optimal power gear, the number of multiple gears is designed according to the user's requirements first. Different gear combinations are used to control the on / off of the insulated bipolar transistor to achieve the maximum number of gears, meet the user's driving habits and the power usage requirements, and improve the user-friendliness of the product.

[0079] In one embodiment, the PTC message information includes the above-mentioned target temperature set by the user, and also includes the maximum power gear of the PTC liquid heater used by the user.

[0080] Introduce the specific process of determining the optimal power gear of the PTC liquid heater based on the relationship between the real-time outlet water temperature and the target temperature. Since the real-time outlet water temperature is a continuously changing quantity, when it is heated to the target temperature, if the heating cannot be maintained, the temperature must continue to drop. Therefore, there are various relationships between the real-time outlet water temperature and the target temperature. Based on different relationships, different operations of the PTC liquid heater are set correspondingly to keep the outlet water temperature within the target temperature range, so as to find the optimal power gear that can keep the outlet water temperature within the target temperature range but does not waste resources. Step 102 includes:

[0081] When the relationship between the real-time outlet water temperature and the target temperature meets the first preset condition, control the PTC liquid heater to stop heating.

[0082] Among them, the first preset condition is that the real-time outlet water temperature is greater than the sum of the target temperature T and the preset floating amount. The preset floating amount can be taken as 1°C - 5°C, such as 1°C, 2°C, 3°C, 4°C, and 5°C.

[0083] When the relationship between the real-time outlet water temperature and the target temperature T meets the second preset condition, control the PTC high-pressure liquid heater to operate at the maximum power level.

[0084] Among them, the second preset condition is that the real-time outlet water temperature is less than the target temperature T.

[0085] When the relationship between the real-time outlet water temperature and the target temperature T meets the third preset condition, query whether there is historical data of the power level corresponding to the target temperature T in the self-learning database. If it exists, execute the experience execution program of the self-learning database to lock the optimal power level corresponding to the target temperature T. If it does not exist, execute the standard program for finding the optimal power level to find the optimal power level.

[0086] Among them, the third preset condition is that the real-time outlet water temperature is greater than or equal to the target temperature T and less than or equal to the sum of the target temperature T and the preset floating amount.

[0087] In one embodiment, for the situation when the above third preset condition is met, the historical data of the power level corresponding to the target temperature T in the self-learning database includes the historical optimal power level corresponding to the target temperature T.

[0088] Among them, executing the experience execution program of the self-learning database to lock the optimal power level corresponding to the target temperature T includes:

[0089] Obtain the historical optimal power level; if the historical optimal power level is less than or equal to the maximum power level, downshift to verify the rationality of the historical optimal power level, and based on the result of the downshift verification, lock the optimal power level corresponding to the target temperature T.

[0090] Exemplarily, the historical optimal power level is less than or equal to the maximum power level, indicating that the power corresponding to the historical optimal power level is less than or equal to the power corresponding to the maximum power level. Downshift to verify the rationality of the historical optimal power level, and based on the result of the downshift verification, lock the optimal power level corresponding to the target temperature T, including:

[0091] Control the PTC high-pressure liquid heater to reduce one gear for heating based on the historical optimal power gear. If the real-time outlet water temperature does not meet the first fixed condition at this time, then heat with the historical optimal power gear. If the real-time outlet water temperature meets the first fixed condition, the result of the gear reduction verification is reasonable. Among them, the first fixed condition includes that the real-time outlet water temperature remains between the difference between the target temperature T and the preset floating amount and the sum of the target temperature T and the preset floating amount for more than the preset time, or the real-time outlet water temperature is greater than the sum of the target temperature T and the preset floating amount.

[0092] For example, the preset floating amount ΔT is set to 3°C, the preset time is set to 1 min, and the historical optimal power gear is the 3rd gear. Heat with the 3rd gear. If the temperature is greater than or equal to T + 3, the PTC stops working, aiming to maintain the temperature between [T, T + 3]. As the temperature drops, when the temperature is less than or equal to T, downshift, and downshift one gear to heat with the 2nd gear. During the heating process with the 2nd gear, if T - 3 ≤ T 实时 ≤ T + 3 cannot be maintained for more than 1 min, then heat with the 3rd gear again. At this time, T - 3 ≤ T 实时 ≤ T + 3 can be maintained for more than 1 min, then the result of the gear reduction verification is reasonable.

[0093] Among them, if after heating with the 3rd gear again, T 实时 >T + 3, then the result of the gear reduction verification can be classified as unreasonable, and it is necessary to continue to downshift based on the 2nd gear, and so on, until T - 3 ≤ T 实时 ≤ T + 3 is maintained for more than 1 min, and the corresponding optimal power gear is found. If T - 3 ≤ T 实时 ≤ T + 3 can never be maintained for more than 1 min, then exit the self-learning database experience execution program, execute the optimal gear search standard program, and use the optimal gear search standard program to find the optimal power gear.

[0094] If the real-time outlet water temperature is less than or equal to the difference between the target temperature T and the preset floating amount at this time, the result of the gear reduction verification is unreasonable; perform an upshift operation until the real-time outlet water temperature meets the first fixed condition. Lock the current power gear that meets the first fixed condition as the optimal power gear corresponding to the target temperature T.

[0095] For example, the preset floating amount ΔT is set to 3°C, the preset time is set to 1 min, and the historical optimal power gear is the 3rd gear. Downshift one gear to heat with the 2nd gear. During the heating process with the 2nd gear, if T 实时 ≤ T - 3, then the result of the gear reduction verification is unreasonable, indicating that the historical optimal power gear recorded in the database can no longer meet the current temperature requirements due to actual situation changes. Then it is necessary to perform an upshift operation to the 3rd gear until T - 3 ≤ T 实时 ≤ T + 3 is maintained for more than 1 min, and the corresponding optimal power gear is found.

[0096] Exemplarily, when there is no experience in the self - learning database or the historical optimal power gear in the self - learning database experience cannot meet the actual temperature requirements, the standard procedure for finding the optimal gear is executed to find the optimal power gear, including:

[0097] Control the PTC high - pressure liquid heater to start running at the minimum power gear and heat to the target temperature T.

[0098] Control the PTC high - pressure liquid heater to increase the gear for heating on the basis of the minimum power gear until the real - time water outlet temperature meets the second fixed condition; the second fixed condition includes that the real - time water outlet temperature remains between the difference between the target temperature T and the preset floating amount and the sum of the target temperature T and the preset floating amount for more than the preset time, or the first measured real - time water outlet temperature is greater than the sum of the target temperature T and the preset floating amount. Wherein, the first measured real - time water outlet temperature is the temperature of the PTC water outlet measured for the first time using the current gear.

[0099] Take the current power gear that meets the second fixed condition as the optimal power gear.

[0100] Taking a 7KW heater as an example, the user requires the target power P of the PTC liquid heater total = 7KW, n = 2, P unit = 1KW, P left = 0, P(1)=1KW, P(2)=2KW, P(3)=4KW, P(4)=4KW, P(5)=5KW, P(6)=6KW, P(7)=7KW. Therefore, the heater can be divided into N = 7 gears. Assuming that the target temperature T in the message is 25°C, the allowable power gear is 7KW and it is enabled to run, and the measured PTC real - time water outlet temperature is 10°C.

[0101] Exemplarily, during the actual operation of the PTC liquid heater, two IGBTs in a group of IGBTs do not start simultaneously. There is a certain delay in their turn - on, that is, after one IGBT starts, the other IGBT will start working after a short delay, which can effectively avoid the impact caused by simultaneous start - up and ensure the heater runs more smoothly and safely.

[0102] At this time, 10°C is less than 25°C, which meets the second preset condition. The real - time water outlet temperature is less than the target temperature T. When the temperature multi - gear self - learning control sub - program corresponding to the temperature multi - gear self - learning control method of the PTC liquid heater is executed for the first time, first heat at the maximum power gear P(7)=7KW. When the PTC real - time water outlet temperature reaches 25°C, it meets the third preset condition that the real - time water outlet temperature is greater than or equal to the target temperature T and less than or equal to the sum of the target temperature T and the preset floating amount of 3°C, which is 28°C.

[0103] Since there is no historical optimal power gear corresponding to the target temperature of 25°C in the self-learning database during the first run, the standard program for finding the optimal gear is executed to find the optimal power gear. The PTC operates at the minimum power gear P(1) = 1KW. During this period, if the real-time water outlet temperature of the PTC drops to 22°C, the PTC heats at 7KW. When the real-time water outlet temperature of the PTC reaches 25°C again, the PTC operates at 2KW, and so on, until the real-time water outlet temperature of the PTC stabilizes between 22°C and 28°C for more than 1 minute or the first water outlet temperature of the PTC exceeds 28°C, then the current gear and the target temperature are stored in the self-learning database; for easy understanding, assume that the optimal power gear when the real-time water outlet temperature of the PTC is 25°C is 4KW. If the PTC executes the temperature multi-gear self-learning control subroutine for the second time, it first heats at 7KW. When the real-time water outlet temperature of the PTC reaches 25°C, the PTC operates at 3KW. When the real-time water outlet temperature of the PTC reaches 22°C, the PTC operates at 4KW, so that the optimal gear of 4KW can be quickly found. The purpose of executing 3KW is to verify whether the 4KW gear is the optimal one; generally, the coolant flow rate of the automotive thermal management system is relatively stable. If the coolant flow rate increases or decreases sharply due to other reasons, the self-learning experience data can also be updated in a timely manner, and the program after reading the self-learning data still has the function of updating the data.

[0104] Exemplarily, if the historical optimal power gear is greater than the maximum power gear, the standard program for finding the optimal gear is executed to find the optimal power gear.

[0105] Among them, the historical optimal power gear being greater than the maximum power gear indicates that the historical optimal power gear does not match the current optimal power gear at this time, and the optimal power gear needs to be re-searched. Another situation is that when executing the standard program for finding the optimal gear, the optimal power gear cannot be found, then the current highest gear cannot achieve the constant temperature effect, which indicates that the host computer allows the PTC power to be too small or other external abnormalities cause it. Therefore, for the PTC, it can only continue to operate at the currently allowed maximum gear.

[0106] In this embodiment, when there is no experience in the self-learning database or due to actual situations such as the coolant flow rate itself changing within a certain range in the actual situation, and the historical optimal power gear in the self-learning database experience cannot meet the actual temperature requirements, the standard program for finding the optimal gear is executed to determine the optimal power gear. The historical optimal power gear in the self-learning database experience can also be used to perform upshift or downshift operations to quickly determine the optimal power gear, reduce the search time, and improve work efficiency.

[0107] It should be noted that the power levels in this embodiment and each embodiment correspond to the power set for the power levels. For the convenience of description in this application, it is set that a large power level corresponds to a large power, and a small power level corresponds to a small power. Of course, in actual applications, it is also possible to use the order of symbols or numbers from small to large to correspond to the power order from large to small, which should not be used as a limiting condition for the solution of this application.

[0108] In one embodiment, after executing the optimal gear search standard program and finding the optimal power gear, the temperature multi-gear self-learning control method of the PTC liquid heater further includes:

[0109] Storing the optimal power gear and the target temperature T corresponding to the optimal power gear into the self-learning database.

[0110] Exemplarily, storing data such as the optimal power gear and the target temperature T corresponding to the optimal power gear into the self-learning database includes recording new data into the self-learning database and updating the historical data in the self-learning database, that is, replacing the historical data with the new data. Among them, updating the historical data in the self-learning database needs to meet any one of the two conditions: one is that this gear can keep the PTC outlet temperature within the range of [T - 3, T + 3] for more than the preset time and is different from the original historical data; the other is that this gear enables the PTC outlet temperature to reach T + 3 for the first time and is different from the original historical data. The historical data includes the historical optimal power gear and the target temperature T corresponding to the historical optimal power gear.

[0111] When the self-learning database records data, it will first compare whether it is the same as the historical data to avoid writing duplicate data and increase the service life of the controller memory module.

[0112] Generally, the coolant flow of the vehicle thermal management system is relatively stable. If the coolant flow increases or decreases sharply due to other reasons, it is also possible to update the self-learning experience data in a timely manner, and the program after reading the self-learning data still has the function of updating data.

[0113] The specific process of the temperature multi-gear self-learning control method of the PTC liquid heater is introduced in the above embodiments. To make the method of this application clearer, the control program logic corresponding to this method is introduced next, such as Figure 2 The temperature multi-gear self-learning control subroutine shown.

[0114] The temperature multi-gear self-learning control subroutine is initialized with i = 0 and j = 1, where j is the accumulator parameter and is subsequently assigned to i. i represents the i-th gear, and the preset temperature floating amount ΔT is set to 3°C. The target temperature T in the PTC message information is set to the temperature Ttg required by the user, and the number of power gear groups N is calculated as Ntg. First, operate at the maximum power gear P(N) for a period of time. If it is monitored that the real-time PTC outlet water temperature is not within [T, T + 3], then determine whether the real-time PTC outlet water temperature is less than T. If so, continue heating at the maximum power gear P(N); otherwise, the real-time PTC outlet water temperature is greater than T + 3, and the PTC stops working.

[0115] If it is monitored that the real-time PTC outlet water temperature is within [T, T + 3], first query whether there is gear historical data corresponding to the target temperature. If there is, read the power gear in the self-learning database and execute the self-learning database experience execution program. Determine whether the historical optimal power gear N' corresponding to the target temperature in the gear historical data is within (1, Ntg) to ensure that the maximum power of the PTC can achieve the historical optimal power gear. If so, heat according to the historical optimal power gear, start delaying the timing of the preset heating time D. At this time, determine whether the real-time PTC outlet water temperature is less than T - 3. If the temperature is too low, less than or equal to T - 3, perform a gear up operation until T - 3 ≤ PTC real-time outlet water temperature ≤ T + 3 for more than 1 minute; otherwise, perform a gear down operation.

[0116] Regarding the gear down timing of the gear down operation, if the real-time outlet water temperature is greater than T - 3, it is necessary to determine whether the real-time outlet water temperature is greater than or equal to T + 3. If not and it lasts for more than 1 minute, the current gear is the optimal power gear, and update this optimal power gear to the self-learning database; if so, the PTC real-time outlet water temperature stops working, maintain the temperature within [T, T + 3), and as the temperature drops, until the temperature is less than or equal to T, then perform a gear down operation. The purpose of performing the gear down operation is to verify whether the historical optimal power gear is the optimal one until T - 3 ≤ PTC real-time outlet water temperature ≤ T + 3 for more than 1 minute, and update the current optimal power gear to the self-learning database.

[0117] If it is determined that the historical optimal power gear N' corresponding to the target temperature in the gear historical data is greater than Ntg, first operate at the Ntg gear and execute the optimal gear search standard program to find the optimal power gear.

[0118] If it is queried that there is no gear historical data corresponding to the target temperature, then execute the optimal gear search standard program. Start delaying the timing of the preset heating time D, and at the same time start searching from the P(1) gear until T - 3 ≤ PTC real-time outlet water temperature ≤ T + 3 for more than 1 minute, or the first measured real-time outlet water temperature is greater than T + 3, and update the current optimal power gear to the self-learning database.

[0119] The temperature multi - gear self - learning control method of the PTC liquid heater in the embodiments of the present application, through the multi - gear self - learning control sub - routine, dynamically adjusts the power gear according to the relationship between the real - time water outlet temperature and the target temperature, designs the number of multi - gears, and different gear combinations are used to control the on - off of the insulated bipolar transistor to achieve the maximum number of gears. On the basis of the maximum number of gears, the optimal gear search standard program and the self - learning database experience execution program are used to quickly find the optimal power gear, avoiding the frequent start - stop problem caused by too large temperature deviation in the traditional control method, thereby reducing the switching times of the heater, quickly selecting the optimal working gear during constant - temperature control, achieving the effect that the IGBT in the PTC high - pressure liquid heater only needs passive heat dissipation and the shape of the heater is not limited, and the constant - temperature effect is better than that of the traditional power - controlled heater, and extending the service life of the equipment. And based on the dynamic adjustment strategy of real - time temperature feedback and target temperature, it can more accurately maintain the set temperature, avoid frequently triggering heating or stopping heating due to too large temperature deviation, so as to realize the two control functions of power gear and constant temperature. In addition, the heater has a self - learning function, can quickly select the optimal working gear during constant - temperature control, realizes that the IGBT only needs passive heat dissipation and the shape of the heater is not limited, and the constant - temperature effect is better than that of the traditional power - controlled heater.

[0120] The present application provides a temperature multi - gear self - learning control system for a PTC liquid heater, which is used to execute the temperature multi - gear self - learning control method of the PTC liquid heater in the above - mentioned embodiments.

[0121] The temperature multi - gear self - learning control system of the PTC liquid heater includes a controller that implements the steps in any of the above - mentioned method embodiments.

[0122] The embodiments of the present application also provide a controller. Refer to Figure 3 , the controller 300 may include: at least one processor 310 and a memory 320. A computer program that can run on at least one processor 310 is stored in the memory 320. When the processor 310 executes the computer program, it implements the steps in any of the above - mentioned method embodiments.

[0123] Exemplarily, the computer program can be divided into one or more modules / units. One or more modules / units are stored in the memory 320 and executed by the processor 310 to complete the present application. One or more modules / units can be a series of computer program segments capable of performing specific functions, and this program segment is used to describe the execution process of the computer program in the controller 300.

[0124] Those skilled in the art can understand, Figure 3These are merely examples of the controller and do not constitute a limitation thereto. It may include more or fewer components than those shown in the figures, or combine certain components, or have different components, such as input / output devices, network access devices, buses, etc.

[0125] The processor 310 may be a central processing unit (CPU), or may also be other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc. The general-purpose processor may be a microprocessor or the processor may also be any conventional processor, etc.

[0126] The memory 320 may be an internal storage unit of the controller, or may also be an external storage device of the controller, such as a plug-in hard disk, a smart media card (SMC), a secure digital (SD) card, a flash card, etc. The memory 320 is used to store computer programs and other programs and data required by the server and the processor. The memory 320 may also be used to temporarily store data that has been output or is to be output.

[0127] The bus may be an industry standard architecture (ISA) bus, a peripheral component interconnect (PCI) bus, an extended industry standard architecture (EISA) bus, etc. The bus may be divided into an address bus, a data bus, a control bus, etc. For ease of representation, the buses in the drawings of the present application are not limited to only one bus or one type of bus.

[0128] The temperature multi-gear self-learning control method for the PTC liquid heater provided by the embodiments of the present application can be applied to controllers such as computers, tablet computers, laptop computers, netbooks, personal digital assistants (PDAs), etc. The embodiments of the present application do not impose any restrictions on the specific type of the controller.

[0129] It should be understood that the magnitudes of the sequence numbers of the steps in the above embodiments do not imply the order of execution. The order of execution of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0130] The above embodiments are only used to illustrate the technical solutions of the present application, rather than limiting them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present application, and should all be included within the protection scope of the present application.

Claims

1. A temperature multi-level self-learning control method for a PTC liquid heater, characterized in that: Each group of PTC distribution in the PTC liquid heater is controlled on and off by at least one insulating bipolar transistor; comprising: When the PTC high-pressure liquid heater enters the constant temperature mode and the target temperature in the PTC message information remains unchanged, obtaining the real-time outlet water temperature of the PTC liquid heater, and determining the relationship between the real-time outlet water temperature and the target temperature; Based on the relationship between the real-time water outlet temperature and the target temperature, the optimal power gear of the PTC liquid heater is determined; the optimal power gear represents the on-off status of the insulated bipolar transistors corresponding to each group of PTCs.

2. The temperature multi-level self-learning control method of a PTC liquid heater according to claim 1, characterized in that: The PTC message information includes the maximum power gear; The determining the optimal power level of the PTC liquid heater based on the relationship between the real-time outlet water temperature and the target temperature includes: When the relationship between the real-time outlet water temperature and the target temperature meets a first preset condition, the PTC liquid heater is controlled to stop heating; the first preset condition is: the real-time outlet water temperature is greater than the sum of the target temperature and a preset floating amount; When the relationship between the real-time outlet water temperature and the target temperature meets a second preset condition, the PTC high-pressure liquid heater is controlled to operate at the maximum power gear; the second preset condition is: the real-time outlet water temperature is less than the target temperature; When the relationship between the real-time water outlet temperature and the target temperature meets the third preset condition, the self-learning database is queried to see whether there is historical data on the gear position corresponding to the target temperature. If so, the self-learning database experience execution program is executed to lock the optimal power gear position corresponding to the target temperature. If not, the optimal gear search standard program is executed to find the optimal power gear position. The third preset condition is that the real-time water outlet temperature is greater than or equal to the target temperature, and less than or equal to the sum of the target temperature and the preset floating amount.

3. The temperature multi-level self-learning control method of a PTC liquid heater according to claim 2, characterized in that: The gear position history data corresponding to the target temperature in the self-learning database includes the historical optimal power gear position corresponding to the target temperature; The executing of the self-learning database experience execution program to lock the optimal power gear corresponding to the target temperature includes: Obtaining the historical optimal power gear; If the historical optimal power gear is less than or equal to the maximum power gear, the rationality of the historical optimal power gear is verified by downshifting, and based on the result of the downshift verification, the optimal power gear corresponding to the target temperature is locked; if the historical optimal power gear is greater than the maximum power gear, the optimal gear search standard procedure is executed to find the optimal power gear.

4. The temperature multi-level self-learning control method of a PTC liquid heater according to claim 2, characterized in that: The method of executing the optimal gear search standard procedure to search for the optimal power gear includes: Controlling the PTC high-voltage liquid heater to start operating at a minimum power gear and heating to a target temperature; Controlling the PTC high-pressure liquid heater to perform up-shift heating on the basis of the minimum power gear until the real-time outlet water temperature meets a second fixed condition; the second fixed condition includes that the real-time outlet water temperature is maintained between the difference between the target temperature and the preset floating amount and the sum of the target temperature and the preset floating amount for more than a preset time, or the real-time outlet water temperature is greater than the sum of the target temperature and the preset floating amount; The current power level that meets the second fixed condition is used as the optimal power level.

5. The temperature multi-level self-learning control method of a PTC liquid heater according to claim 2, characterized in that: After executing the optimal gear search standard procedure to find the optimal power gear, the temperature multi-gear self-learning control method of the PTC liquid heater further includes: The optimal power gear and the target temperature corresponding to the optimal power gear are stored in a self-learning database.

6. The temperature multi-level self-learning control method of a PTC liquid heater according to claim 3, characterized in that: The downshifting verifies the rationality of the historical optimal power gear, and based on the result of the downshifting verification, locks the optimal power gear corresponding to the target temperature, including: The PTC high-pressure liquid heater is controlled to heat at a lower level based on the historical optimal power level. If the real-time outlet water temperature does not meet the first fixed condition at this time, heating is performed at the historical optimal power level again. If the real-time outlet water temperature meets the first fixed condition, the result of the downshift verification is reasonable. The first fixed condition includes that the real-time outlet water temperature is maintained between the difference between the target temperature and the preset floating amount and the sum of the target temperature and the preset floating amount for more than a preset time, or the real-time outlet water temperature is greater than the sum of the target temperature and the preset floating amount. If the real-time outlet water temperature is less than or equal to the difference between the target temperature and the preset floating amount, the result of the downshift verification is unreasonable; an upshift operation is performed until the real-time outlet water temperature meets the first fixed condition; The current power level that meets the first fixed condition is locked to the optimal power level corresponding to the target temperature.

7. The temperature multi-level self-learning control method of a PTC liquid heater according to claim 1, characterized in that: Before determining the optimal power level of the PTC liquid heater, the method further includes: Determine multiple power levels based on the target power of the PTC liquid heater required by the user; Based on the multiple power gears, a combination of different gears is determined; the combination of different gears is used to control the on and off of the insulated bipolar transistor to achieve a maximum number of gears.

8. The temperature multi-level self-learning control method of a PTC liquid heater according to claim 7, characterized in that: The method of determining multiple power levels based on the target power of the PTC liquid heater required by the user includes: Obtaining the unit power of the PTC liquid heater; Determining the supplementary power based on the target power of the PTC liquid heater required by the user and the unit power; Based on the supplementary power and the unit power, multiple power gears are determined.

9. The temperature multi-level self-learning control method of a PTC liquid heater according to claim 7, characterized in that: The multiple power gears are expressed as: P(N)=N n+1 P left +(N n 2 n +N n-1 2 n-1 ...+N02 0 )P unit Where, P(N) is the power of the Nth gear; N n+1 、N n 、N n-1 ...N0 is a Boolean coefficient; P left To supplement power; P unit is the unit power.

10. A temperature multi-level self-learning control system for a PTC liquid heater, characterized in that: Used to execute the temperature multi-level self-learning control method of a PTC liquid heater as claimed in any one of claims 1 to 9.

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