air conditioning unit

Abstract

This invention discloses an air conditioning device that determines the initial and equilibrium temperatures of a power module; controls the compressor's operating state to ensure the IGBT output current has a relative zero temperature coefficient; determines the total power module losses at the equilibrium temperature based on the IGBT's relative zero temperature coefficient parameters; acquires the thermal resistance of the inverter driver and refrigerant radiator, and determines the theoretical temperature based on the thermal resistance and total losses; determines the theoretical temperature rise based on the theoretical and initial temperatures, and determines the measured temperature rise based on the equilibrium and initial temperatures; determines the deviation value based on the theoretical and measured temperature rises; acquires the standard deviation value, and compares the deviation value with the standard deviation value to determine whether the refrigerant radiator is qualified. The air conditioning device can intelligently assess the reliability of the refrigerant radiator and its installation.

Description

Technical Field

[0001] This invention relates to the field of air conditioning technology, and in particular to an air conditioning device. Background Technology

[0002] To improve the reliability of inverter drives, air conditioning units generally use refrigerant radiators with strong heat dissipation capacity and high heat dissipation efficiency to cool the inverter drives.

[0003] The inverter drive and refrigerant radiator are assembled during product manufacturing. However, the accuracy of this assembly determines whether the refrigerant radiator can properly cool the inverter drive. Current technology typically relies on visual inspection to determine assembly accuracy, which introduces significant errors and lacks precision.

[0004] The information disclosed in this background section is only intended to enhance the understanding of the background technology of this application, and therefore may include prior art that is not known to those skilled in the art. Summary of the Invention

[0005] This invention proposes an air conditioning device that solves the technical problem that existing technologies cannot confirm whether the refrigerant radiator of a frequency converter driver is qualified.

[0006] To achieve the above-mentioned objectives, the present invention employs the following technical solution:

[0007] An air conditioning unit, comprising:

[0008] Refrigerant circulation loop, including the compressor;

[0009] Variable frequency drives, including:

[0010] Power modules, including IGBTs and diodes;

[0011] Temperature detection module, used to detect the temperature of the power module;

[0012] The refrigerant radiator is assembled with the frequency converter and connected to the refrigerant circulation loop via a refrigerant valve.

[0013] The air conditioning unit also includes:

[0014] The current detection module detects the IGBT output current.

[0015] The control module is configured as follows:

[0016] Control the compressor operation and open the refrigerant valve;

[0017] Determine the initial temperature and equilibrium temperature of the power module;

[0018] The compressor's operating status is controlled so that the IGBT output current is a current with a relative zero temperature coefficient.

[0019] Determine the total power module loss at equilibrium temperature based on the IGBT's relative zero temperature coefficient parameter;

[0020] Obtain the thermal resistance of the frequency converter driver and refrigerant radiator, and determine the theoretical temperature based on the thermal resistance and total loss; determine the theoretical temperature rise based on the theoretical temperature and initial temperature, and determine the measured temperature rise based on the equilibrium temperature and initial temperature; determine the deviation value based on the theoretical temperature rise and the measured temperature rise.

[0021] Obtain the standard deviation value and compare the deviation value with the standard deviation value to determine whether the refrigerant radiator is qualified.

[0022] The above technical solution has the following advantages or beneficial effects: the air conditioning unit determines the deviation value by comparing the theoretical temperature change with the actual temperature change of the power module based on the power module loss estimation and thermal resistance determination under a specific state, based on the IGBT relative zero temperature coefficient parameter, and compares it with the predetermined standard deviation value to determine whether the refrigerant radiator and its assembly with the frequency converter driver are qualified, and can intelligently evaluate the reliability of the refrigerant radiator and its installation.

[0023] In some embodiments, the total losses of the power module include IGBT conduction losses, diode conduction losses, IGBT switching losses, and diode switching losses, determined based on the IGBT's relative zero temperature coefficient parameter.

[0024] The above technical solution has the following advantages or beneficial effects: IGBT conduction loss, diode conduction loss, IGBT switching loss and diode switching loss determined based on the IGBT relative zero temperature coefficient parameter can avoid the errors and uncertainties caused by temperature changes, and can make up for the instability of the temperature sensitive saturation voltage drop detection method, so as to make the total loss of the power module more accurate, thereby ensuring the accuracy of the theoretical temperature rise, and thus more accurately judging whether the refrigerant heat sink and the frequency converter driver are assembled.

[0025] In some embodiments, the control module is configured as follows:

[0026] Determine the IGBT saturation voltage drop at relative zero temperature coefficient, the diode freewheeling current at relative zero temperature coefficient, and the diode forward voltage drop at relative zero temperature coefficient current based on the IGBT relative zero temperature coefficient current.

[0027] IGBT conduction losses are determined based on the IGBT's relative zero temperature coefficient current and IGBT's relative zero temperature coefficient saturation voltage drop.

[0028] The diode conduction loss is determined based on the diode freewheeling current value under IGBT relative zero temperature coefficient current and the diode forward voltage drop under IGBT relative zero temperature coefficient current.

[0029] The above technical solution has the following advantages or beneficial effects: controlling the IGBT output current to reach the relative zero temperature coefficient current, determining the IGBT conduction loss by the IGBT relative zero temperature coefficient current and the IGBT relative zero temperature coefficient saturation voltage drop, and determining the diode conduction loss by the diode freewheeling current value under the IGBT relative zero temperature coefficient current and the diode forward conduction voltage drop under the IGBT relative zero temperature coefficient current, eliminating the need for actual current and voltage detection, avoiding detection errors, and improving detection speed and accuracy.

[0030] In some embodiments, the control module is configured as follows:

[0031] Obtain the switching frequency and duty cycle of the power module;

[0032] IGBT conduction losses are determined based on IGBT relative zero temperature coefficient current, IGBT relative zero temperature coefficient saturation voltage drop, switching frequency, and conduction duty cycle.

[0033] The diode conduction loss is determined based on the diode freewheeling current value under IGBT relative zero temperature coefficient current, the diode forward conduction voltage drop under IGBT relative zero temperature coefficient current, the switching frequency, and the conduction duty cycle.

[0034] The above technical solution has the following advantages or beneficial effects: the power module loss is related to the switching frequency and the duty cycle. Therefore, the switching frequency and the duty cycle are introduced to improve the accuracy of loss determination.

[0035] In some embodiments,

[0036] IGBT conduction loss = switching frequency * IGBT relative zero temperature coefficient current * IGBT relative zero temperature coefficient saturation voltage drop;

[0037] Diode conduction loss = switching frequency * (1 - conduction duty cycle) * diode freewheeling current value based on IGBT relative zero temperature coefficient current * diode forward conduction voltage drop based on IGBT relative zero temperature coefficient current.

[0038] The above technical solution has the following advantages or beneficial effects: it provides a specific method for determining the conduction loss of IGBTs and diodes, thereby improving the accuracy of loss determination.

[0039] In some embodiments, the air conditioning unit includes:

[0040] The storage module is used to store the correlation between IGBT switching losses and IGBT relative zero temperature coefficient current at several temperatures, and to store the correlation between diode switching losses and IGBT relative zero temperature coefficient current at several temperatures.

[0041] The control module is configured to determine the IGBT switching losses and diode switching losses based on the IGBT's relative zero temperature coefficient current, equilibrium temperature, and the storage module.

[0042] The above technical solution has the following advantages or beneficial effects: the correlation between IGBT switching losses, diode switching losses and IGBT relative zero temperature coefficient current is determined in advance, and the IGBT switching losses and diode switching losses are determined based on the IGBT relative zero temperature coefficient current, equilibrium temperature and storage module, which can improve the accuracy of the determination of switching losses.

[0043] In some embodiments, the thermal resistance of the frequency converter driver is determined by the thermal resistance value corresponding to the equilibrium temperature of the thermal resistance curve, and the thermal resistance of the refrigerant radiator is the standard thermal resistance of a qualified refrigerant radiator that has been determined in advance.

[0044] The above technical solution has the following advantages or beneficial effects: the thermal resistance of the frequency converter driver is a stable thermal resistance at the equilibrium temperature and will not change; the thermal resistance of the refrigerant heat sink is a standard thermal resistance; therefore, the theoretical temperature can be accurately determined.

[0045] In some embodiments, the equilibrium temperature is the temperature at which the real-time temperature detected by the temperature detection module remains constant within a set time period.

[0046] The above technical solution has the following advantages or beneficial effects: when the temperature of the frequency converter remains unchanged within a set time after setting a balance temperature, it indicates that the frequency converter has reached a thermal equilibrium state.

[0047] In some embodiments, the control module is configured to acquire a predetermined compressor target frequency, control the compressor operating frequency to reach the compressor target frequency, and then control the compressor operating state so that the IGBT output current is a relative zero temperature coefficient current.

[0048] The above technical solution has the following advantages or beneficial effects: first, the operating frequency of the compressor is controlled to reach the target frequency, and then the operating state of the compressor is adjusted so that the output current of the IGBT is a relative zero temperature coefficient current, so as to improve the speed at which the output current of the IGBT reaches the relative zero temperature coefficient current.

[0049] In some embodiments, the control module is configured to determine the theoretical temperature by multiplying the thermal resistance by the total loss.

[0050] The above technical solution has the following advantages or beneficial effects: the theoretical temperature is determined by multiplying the thermal resistance and the total loss, thus ensuring the uniformity of the theoretical temperature determination.

[0051] Other features and advantages of the present invention will become clearer after reading the detailed embodiments of the invention in conjunction with the accompanying drawings. Attached Figure Description

[0052] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0053] Figure 1 This is an exploded view of the variable frequency drive and refrigerant radiator;

[0054] Figure 2 This is a schematic diagram according to an embodiment;

[0055] Figure 3 This is a flowchart of the detection process according to an embodiment;

[0056] Figure 4 This is a flowchart illustrating the total loss estimation process according to an embodiment.

[0057] Figure 5 This is a flowchart illustrating the compressor frequency adjustment process according to an embodiment.

[0058] Figure 6 This is a graph showing the relative zero temperature coefficient of the IGBT according to an embodiment;

[0059] Figure 7 This is a graph showing the relationship between the diode freewheeling current and forward voltage drop according to the embodiment.

[0060] Figure 8 This is a graph showing the relationship between IGBT switching losses and current according to an embodiment.

[0061] Figure 9 This is a graph showing the relationship between diode switching losses and current according to an embodiment.

[0062] Figure 10 This is a diagram showing the correspondence between thermal resistance and frequency converter according to an embodiment;

[0063] Figure 11 The thermal resistance curves of the IGBT and diode according to the embodiment are shown. Detailed Implementation

[0064] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0065] In the description of this application, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0066] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, unless otherwise stated, "a plurality of" means two or more.

[0067] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0068] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0069] The following disclosure provides many different embodiments or examples for implementing various structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described below. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0070] The air conditioning unit disclosed in this application performs a refrigeration cycle by using a compressor, a condenser, a throttling device, and an evaporator. The refrigeration cycle includes a series of processes involving compression, condensation, expansion, and evaporation to cool or heat an indoor space.

[0071] Low-temperature, low-pressure refrigerant enters the compressor, which compresses it into a high-temperature, high-pressure refrigerant gas and discharges the compressed refrigerant gas. The discharged refrigerant gas flows into the condenser. The condenser condenses the compressed refrigerant into a liquid phase, and the heat is released to the surrounding environment through the condensation process.

[0072] The throttling device expands the high-temperature, high-pressure liquid refrigerant that condenses in the condenser into a low-pressure liquid refrigerant. The evaporator evaporates the expanded refrigerant in the throttling device, returning the low-temperature, low-pressure refrigerant gas to the compressor. The evaporator achieves its cooling effect by utilizing the latent heat of refrigerant evaporation to exchange heat with the material being cooled. Throughout the cycle, the air conditioner regulates the temperature of the indoor space.

[0073] The outdoor unit of an air conditioning unit refers to the part of the refrigeration cycle that includes the compressor and the outdoor heat exchanger. The throttling device is located in the outdoor unit.

[0074] The indoor and outdoor heat exchangers function as either condensers or evaporators. When the indoor heat exchanger is used as a condenser, the air conditioner functions as a heater in heating mode; when the indoor heat exchanger is used as an evaporator, the air conditioner functions as a cooler in cooling mode.

[0075] The air conditioning unit includes a variable frequency drive.

[0076] In some embodiments, the air conditioning unit drives the compressor via a variable frequency drive.

[0077] In some embodiments, the air conditioning unit drives the compressor and fan via a variable frequency drive.

[0078] Since the variable frequency drive includes a power module, the power module generates a lot of heat when the variable frequency drive is running. It is necessary to dissipate heat from the power module to ensure its normal operation. Therefore, a refrigerant heat sink needs to be installed on the variable frequency drive to dissipate heat.

[0079] The proper assembly of the refrigerant radiator and its connection to the inverter driver is crucial for the radiator to meet heat dissipation standards. Improper assembly, either of the radiator itself or its connection to the inverter driver, will significantly reduce the radiator's cooling efficiency, leading to excessively high power module temperatures and impacting its lifespan. Therefore, ensuring that the refrigerant radiator and its assembly with the inverter driver meet the heat dissipation requirements of the power module is a key issue that air conditioning systems must address. The air conditioning system is used to test the inverter driver.

[0080] First, let's explain the variable frequency drive:

[0081] exist Figure 1 In the example, the frequency converter driver includes: a power module, a frequency converter driver heat sink, a frequency converter driver board, and a temperature detection module.

[0082] The power module includes IGBTs and diodes.

[0083] The power module is mounted on the frequency converter drive board.

[0084] The frequency converter drive heat sink is assembled with the power module to provide heat dissipation for the power module.

[0085] Variable frequency drive heat sinks are typically assembled by clamping the heat sink to the power module using brackets, screws, or other fixing methods.

[0086] In some embodiments, a thermally conductive layer or structure may be added between the heat sink and the power module to improve heat dissipation.

[0087] The temperature detection module is used to detect the temperature of the power module.

[0088] Variable frequency drives are generally purchased as finished products. The variable frequency drive heat sink and power module of the variable frequency drive itself are properly assembled and meet the heat dissipation standards.

[0089] During the assembly of an air conditioning unit, it is necessary to assemble the refrigerant radiator and the inverter drive.

[0090] Since the heat generation performance of the power module, the assembly of the frequency converter driver itself, and the heat dissipation performance of the frequency converter driver heat sink are all determined under specific conditions, the assembly relationship between the refrigerant heat sink and the frequency converter driver plays a crucial role in the heat dissipation performance of the refrigerant heat sink under these specific conditions. Therefore, it is necessary to test whether the assembly of the refrigerant heat sink and the frequency converter driver is qualified.

[0091] The air conditioning unit involves testing whether the assembly of the radiator and power module is qualified and meets the heat dissipation requirements.

[0092] The air conditioning unit is described below:

[0093] exist Figure 2 In one example, the air conditioning unit includes:

[0094] The refrigerant circulation loop includes the compressor.

[0095] In some embodiments, the refrigerant circulation loop includes a compressor, a four-way valve, an indoor heat exchanger, a throttling device, and an outdoor heat exchanger.

[0096] The refrigerant radiator is assembled with the frequency converter and connected to the refrigerant circulation loop via a refrigerant valve.

[0097] The refrigerant valve is used to control whether refrigerant flows through the refrigerant radiator.

[0098] The current detection module detects the output current of the IGBT.

[0099] The control module is configured as follows:

[0100] Control the compressor operation and open the refrigerant valve.

[0101] Determine the initial temperature and equilibrium temperature of the power module;

[0102] The compressor's operating status is controlled so that the IGBT output current is a current with a relative zero temperature coefficient.

[0103] Determine the total power module loss at equilibrium temperature based on the IGBT's relative zero temperature coefficient parameter;

[0104] Obtain the thermal resistance of the frequency converter driver and refrigerant radiator, and determine the theoretical temperature based on the thermal resistance and total loss; determine the theoretical temperature rise based on the theoretical temperature and initial temperature, and determine the measured temperature rise based on the equilibrium temperature and initial temperature; determine the deviation value based on the theoretical temperature rise and the measured temperature rise.

[0105] Obtain the standard deviation value and compare the deviation value with the standard deviation value to determine whether the refrigerant radiator is qualified.

[0106] The testing device determines the deviation value by comparing the theoretical temperature change based on the power module loss estimation and thermal resistance determination under a specific state with the actual temperature change of the power module. It then compares this deviation value with a pre-determined standard deviation value to determine whether the refrigerant radiator is qualified. This device can intelligently assess the reliability of the installation of the frequency converter drive and the refrigerant radiator.

[0107] The tested air conditioning unit demonstrates that the refrigerant radiator ensures the normal operation of the power module and extends its lifespan. The testing method for the air conditioning unit is simple, reliable, highly implementable, and convenient and quick.

[0108] In some embodiments, the air conditioning unit is started by controlling the compressor to operate. At this time, the refrigerant circulation loop realizes the circulation of refrigerant. In embodiments where the throttling device is an expansion valve, the expansion valve is in the open state.

[0109] The refrigerant valve opens to circulate the refrigerant to the refrigerant radiator, at which point the refrigerant radiator is in cooling mode.

[0110] In some embodiments, the indoor fan and the outdoor fan operate at a certain speed.

[0111] In embodiments where the throttling device is an expansion valve, the expansion valve is in the open state.

[0112] The initial temperature represents the ambient temperature. The ambient temperature remains constant or changes only slightly throughout the entire testing process and is therefore negligible.

[0113] In some embodiments, the equilibrium temperature is the temperature at which the power module reaches a stable state (thermal equilibrium state) after the temperature has risen for a period of time, that is, the temperature at which the temperature remains unchanged.

[0114] In some embodiments, the equilibrium temperature is the temperature at which the real-time temperature detected by the temperature detection module remains constant within a set time period.

[0115] The equilibrium temperature varies under different testing conditions.

[0116] In some embodiments, the thermal resistance of the frequency converter is determined by the thermal resistance value corresponding to the equilibrium temperature of the thermal resistance curve, and the thermal resistance of the refrigerant radiator includes the thermal resistance of the refrigerant radiator itself and the assembly thermal resistance between the refrigerant radiator and the frequency converter.

[0117] In some embodiments, the refrigerant radiator is a finished product with a fixed thermal resistance. The assembly thermal resistance between the refrigerant radiator and the inverter driver is a standard thermal resistance determined in advance based on the successful assembly of the refrigerant radiator and the inverter driver.

[0118] In some embodiments, the refrigerant radiator is an assembled product with an uncertain thermal resistance. The thermal resistance of the refrigerant radiator is a first standard thermal resistance determined in advance based on the condition that the refrigerant radiator is qualified. The assembly thermal resistance between the refrigerant radiator and the inverter driver is a second standard thermal resistance determined in advance based on the condition that the refrigerant radiator and the inverter driver are assembled successfully.

[0119] exist Figure 10 In this example, the thermal resistance of the frequency converter driver includes the thermal resistance R of the power module. th1 , drive heatsink thermal resistance R th3 The assembly thermal resistance R between the two th2 .

[0120] Power module thermal resistance R th1At equilibrium temperature, the thermal resistance R of the driving heatsink is a fixed value. th3 The assembly thermal resistance R between the two th2 All values ​​are constants at equilibrium temperature.

[0121] Power module thermal resistance R th1 and heat sink thermal resistance R th3 These represent the thermal resistance values ​​corresponding to their respective thermal resistance curves at the equilibrium temperature.

[0122] exist Figure 11 In the example, the thermal resistance curves of the IGBT and diode of the power module are shown.

[0123] The thermal resistance R between the refrigerant radiator and its assembly with the inverter drive th4 The standard thermal resistance R is determined in advance based on the refrigerant radiator when it is successfully assembled with the inverter drive. th4 .

[0124] Inverter driver thermal resistance (R) th1 R th2 R th3 At equilibrium temperature, the thermal resistance is stable and will not change; the assembly thermal resistance is the standard thermal resistance (R). th4 Therefore, the theoretical temperature can be determined accurately.

[0125] In some embodiments, the control module is configured with a total thermal resistance (R) th1 R th2 R th3、 R th4 The theoretical temperature is determined by multiplying the total loss by the total loss.

[0126] The theoretical temperature is determined by multiplying the total thermal resistance by the total loss, thus establishing a consistent method for determining the theoretical temperature and ensuring uniformity in its determination.

[0127] In some embodiments, theoretical temperature = total thermal resistance (R) th1 R th2 R th3 R th4 Total loss.

[0128] Since the relative zero temperature coefficient parameter of IGBT is an inherent parameter of IGBT, it can be obtained through... Figure 6 Curve acquisition.

[0129] In some embodiments, the relative zero temperature coefficient parameter of the IGBT is stored in a storage module.

[0130] In some embodiments, the thermal resistance (R) of the frequency converter driver is stored in the storage module. th1 R th2 R th3), the thermal resistance R between the refrigerant radiator and the inverter drive th4 .

[0131] The standard deviation is a deviation value that meets the requirements and is determined in advance through experiments.

[0132] In some embodiments, the standard deviation value is stored in a storage module.

[0133] In some embodiments, the output module outputs information on whether the heat sink and power module are properly assembled.

[0134] exist Figure 3 In this example, the detection process for the empty baton jumping device is as follows:

[0135] S1, Begin.

[0136] S2, Detect the initial temperature of the power module.

[0137] S3 controls the operation of the air conditioning unit. The inverter driver generates heat and dissipates it through the refrigerant radiator.

[0138] S4. Determine the IGBT's relative zero temperature coefficient current.

[0139] S5. Adjust the compressor operating status to regulate the IGBT output current.

[0140] S6. Detect the output current of the IGBT.

[0141] S7. Is the output current of the IGBT a relative zero temperature coefficient current? If yes, proceed to step S8; otherwise, proceed to step S6.

[0142] S8, Detect the real-time temperature of the power module.

[0143] S9. If the real-time temperature remains unchanged within the set time, proceed to step S10; otherwise, proceed to step S8.

[0144] S10. Determine the real-time temperature as the equilibrium temperature.

[0145] S11. Determine the total power module loss at equilibrium temperature based on the IGBT relative zero temperature coefficient parameter.

[0146] S12. Obtain the thermal resistance of the frequency converter driver and the refrigerant heat sink. Determine the theoretical temperature based on the total thermal resistance and total loss. Determine the theoretical temperature rise based on the theoretical temperature and the initial temperature. Determine the measured temperature rise based on the equilibrium temperature and the initial temperature. Determine the deviation value based on the theoretical temperature rise and the measured temperature rise. Obtain the standard deviation value.

[0147] S13. If the deviation value is within the standard deviation threshold range, proceed to step S14; otherwise, proceed to step S15.

[0148] S14. The refrigerant radiator and frequency converter are assembled successfully.

[0149] S15. The refrigerant radiator and the frequency converter driver are not properly assembled.

[0150] In some embodiments, the total loss of the power module includes IGBT conduction loss determined based on the IGBT relative zero temperature coefficient parameter, diode conduction loss determined based on the IGBT relative zero temperature coefficient parameter, IGBT switching loss determined based on the IGBT relative zero temperature coefficient parameter, and diode switching loss determined based on the IGBT relative zero temperature coefficient parameter.

[0151] The IGBT conduction loss, diode conduction loss, IGBT switching loss, and diode switching loss determined based on the IGBT relative zero temperature coefficient parameters can avoid errors and uncertainties caused by temperature changes. This can compensate for the instability of temperature-sensitive saturation voltage drop detection methods, making the determination of the total loss of the power module more accurate, thereby ensuring the accuracy of the theoretical temperature rise and thus more accurately judging whether the refrigerant heat sink and frequency converter are properly assembled.

[0152] The methods for determining IGBT conduction losses, diode conduction losses, and switching losses based on IGBT relative zero temperature coefficient parameters employ the Vcesat (IGBT saturation voltage drop) detection method under the IGBT relative zero temperature coefficient system current. The so-called relative zero temperature coefficient current Vcesat (IGBT saturation voltage drop) detection method is based on the fact that the IGBT power device in the frequency converter drive power module can be equivalent to a diode and MOSFET in series conduction mode when turned on. Temperature changes affect the intrinsic carrier concentration and the bipolar diffusion coefficient, hence diodes have a negative temperature coefficient (NTC) characteristic. However, for MOSFETs, temperature affects the threshold voltage Vth and mobility μ, thus exhibiting a typical positive temperature coefficient (PTC) characteristic. Therefore, the IGBT in the frequency converter drive module exhibits a negative temperature coefficient characteristic at low conduction currents and a positive temperature coefficient characteristic at high conduction currents. Therefore, the point where these characteristics diverge is considered the relative zero temperature coefficient point. Figure 8As shown, its advantage is that this point is insensitive to temperature changes, corresponding to a specific conducting current value of the IGBT in the frequency converter power module. Therefore, under this specific current, Vcesat (IGBT saturation voltage drop) is a fixed value. This eliminates errors caused by temperature and many uncertain factors. Thus, it can compensate for the instability of temperature-sensitive Vcesat detection methods. Based on the IGBT switching losses and diode switching losses determined by the relative zero temperature coefficient parameter, the switching losses of the power module can be estimated more accurately.

[0153] In some embodiments, the control module is configured as follows:

[0154] Based on the IGBT's relative zero temperature coefficient current I CZERO Determine the saturation voltage drop V of the IGBT with relative zero temperature coefficient. cezero The diode freewheeling current value I of IGBT under relative zero temperature coefficient current Fref Compared to IGBT, the forward voltage drop V of the diode under zero temperature coefficient current is... Fref .

[0155] exist Figure 6 In the example, the IGBT's relative zero temperature coefficient current I is determined by the IGBT current versus voltage drop curve. CZERO and the relative zero temperature coefficient saturation voltage drop V of IGBT cezero .

[0156] exist Figure 7 In the example, the diode freewheeling current value I under the IGBT relative zero temperature coefficient current is determined by the diode freewheeling current value and the forward voltage drop curve. Fref Compared to IGBT, the forward voltage drop V of the diode under zero temperature coefficient current is... Fref .

[0157] The control module is configured to operate based on the IGBT's relative zero temperature coefficient current I. CZERO The relative zero temperature coefficient saturation voltage drop V of IGBT cezero Determine the IGBT conduction loss E con .

[0158] The control module is configured to operate based on the IGBT's relative zero temperature coefficient current I. CZERO The diode freewheeling current value I Fref and the IGBT relative zero temperature coefficient current I CZERO The forward voltage drop V of the diode below Fref Determine the diode conduction loss E Dcon .

[0159] Controlling the IGBT output current to achieve a relative zero temperature coefficient current I CZEROWith the IGBT's relative zero temperature coefficient current I CZERO The relative zero temperature coefficient saturation voltage drop V of IGBT cezero Determine the IGBT conduction loss E con With the IGBT having a relative zero temperature coefficient current I CZERO The diode freewheeling current value I Fref and the IGBT relative zero temperature coefficient current I CZERO The forward voltage drop V of the diode below Fref Determine the diode conduction loss E Dcon It eliminates the need for actual current and voltage detection, avoiding detection errors and improving detection speed and accuracy.

[0160] In some embodiments, the control module is configured as follows:

[0161] Obtain the switching frequency fsw and duty cycle d of the power module;

[0162] The control module is configured to operate based on the IGBT's relative zero temperature coefficient current I. CZERO IGBT relative zero temperature coefficient saturation voltage drop V cesat The switching frequency fsw and the duty cycle d determine the IGBT conduction loss.

[0163] In some embodiments, the IGBT conduction loss E con = Switching frequency fsw * IGBT relative zero temperature coefficient current I CZERO *IGBT relative zero temperature coefficient saturation voltage drop V cesat .

[0164] The control module is configured to operate based on the IGBT's relative zero temperature coefficient current I. CZERO The diode freewheeling current value I Fref IGBT relative zero temperature coefficient current I CZERO The forward voltage drop V of the diode below Fref The switching frequency fsw and the duty cycle d determine the diode's conduction loss E. Dcon .

[0165] In some embodiments, the diode conduction loss E Dcon = Switching frequency fsw * (1 - On duty cycle d) * Current I based on the IGBT's relative zero temperature coefficient CZERO The diode freewheeling current value I Fref *IGBT relative zero temperature coefficient current I CZERO The forward voltage drop V of the diode below Fref .

[0166] Power module losses are related to the switching frequency fsw and the duty cycle d. Therefore, the switching frequency and duty cycle are introduced to improve the accuracy of loss determination. Furthermore, specific methods for determining IGBT conduction losses and diode conduction losses are provided to further improve the accuracy of loss determination.

[0167] In some embodiments, the air conditioning unit includes:

[0168] The storage module is used to store the IGBT switching losses (IGBT turn-on losses E) at several temperatures. on and IGBT turn-off loss E off The relative zero temperature coefficient current I of the IGBT CZERO The correlation is used to store the diode switching loss (diode reverse recovery loss Erec) and the IGBT relative zero temperature coefficient current I at certain temperatures. CZERO The relationship between them.

[0169] The control module is configured to operate based on the IGBT's relative zero temperature coefficient current I. CZERO Balancing temperature and storage modules determines IGBT switching losses (IGBT turn-on losses E). on and IGBT turn-off loss E off ) and diode switching loss (diode reverse recovery loss Erec).

[0170] Predetermine certain temperature-related IGBT switching losses (IGBT turn-on losses E). on and IGBT turn-off loss E off Diode switching loss (diode reverse recovery loss Erec) and IGBT relative zero temperature coefficient current I CZERO The correlation is based on the IGBT's relative zero temperature coefficient current I. CZERO Balancing temperature and storage modules determines IGBT switching losses (IGBT turn-on losses E). on and IGBT turn-off loss E off The determination accuracy of switching losses can be improved by considering diode switching losses (diode reverse recovery loss Erec) and diode switching losses (diode reverse recovery loss Erec).

[0171] exist Figure 8 In the example, the IGBT turn-on loss E of the power module at equilibrium temperature is read from the storage module. on Current-current relationship curve, IGBT turn-off loss E off Find the IGBT's relative zero temperature coefficient current I based on the current-temperature relationship curve. CZERO The corresponding IGBT turn-on loss E at (10A) on (1.5mJ) and IGBT turn-off loss E off (1.4mJ).

[0172] exist Figure 9 In this example, the power stored in the storage module is read; the diode reverse recovery loss Erec versus current curve at equilibrium temperature is used to find the IGBT relative zero temperature coefficient current I. CZERO The diode reverse recovery loss Erec at (10A) is 1.15mJ.

[0173] IGBT loss E IGBT-toal Including IGBT conduction loss E con With IGBT switching loss E sw .

[0174] E IGBT-toal =E con +E sw =E con +E on +E off .

[0175] Diode loss E DIODE-Total Including diode conduction loss E Dcon With diode switching loss E Dsw .

[0176] E DIODE-Total =E Dcon +E Dsw =E Dcon +Erec.

[0177] Total losses include IGBT losses E IGBT-toal and diode loss E DIODE-Total .

[0178] Total loss P toal =6*E IGBT-toal +6*E DIODE-Total .

[0179] The process for determining the total loss is as follows: Figure 4 As shown.

[0180] In some embodiments, the control module is configured to acquire a predetermined compressor target frequency, control the compressor operating frequency to reach the compressor target frequency, and then control the compressor operating state so that the IGBT output current is a relative zero temperature coefficient current.

[0181] First, control the compressor's operating frequency to reach the target frequency, which is a predetermined frequency that can reach near the relative zero temperature coefficient current threshold, in order to accelerate the speed of output current adjustment. Then, finely adjust the compressor's operating state so that the IGBT output current is a relative zero temperature coefficient current, in order to improve the speed at which the IGBT output current reaches the relative zero temperature coefficient current.

[0182] exist Figure 5 In this example, the compressor frequency regulation process is as follows:

[0183] S1, Begin.

[0184] S2, the compressor starts, the refrigerant valve opens, and the indoor and outdoor fans start to the set speed.

[0185] S3. Obtain the target frequency of the compressor.

[0186] S4. Adjust the compressor frequency.

[0187] S5. Has the compressor frequency reached the target frequency? If yes, proceed to step S6; otherwise, proceed to step S4.

[0188] S6. Detect the IGBT output current.

[0189] S7. Does the IGBT output current reach the relative zero temperature coefficient current? If yes, proceed to step S8; otherwise, proceed to step S9.

[0190] S8, keep the compressor frequency constant.

[0191] S9. Adjust the compressor frequency and proceed to step S6.

[0192] The air conditioning unit automatically detects the reliability and proper installation of the refrigerant radiator, avoiding customer complaints caused by power device damage and abnormal alarms due to insufficient refrigerant radiator reliability and proper installation, thus ensuring product reliability. In the description of the above embodiments, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.

[0193] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. An air conditioning unit, comprising: Refrigerant circulation loop, including the compressor; Variable frequency drives, including: Power modules, including IGBTs and diodes; Temperature detection module, used to detect the temperature of the power module; The refrigerant radiator is assembled with the frequency converter and connected to the refrigerant circulation loop via a refrigerant valve. Its characteristic is that it further includes: The current detection module detects the IGBT output current. The control module is configured as follows: Control the compressor operation and open the refrigerant valve; Determine the initial temperature and equilibrium temperature of the power module; The compressor's operating status is controlled so that the IGBT output current is a current with a relative zero temperature coefficient. Determine the total power module loss at equilibrium temperature based on the IGBT's relative zero temperature coefficient parameter; Obtain the thermal resistance of the frequency converter driver and refrigerant radiator, and determine the theoretical temperature based on the thermal resistance and total loss; determine the theoretical temperature rise based on the theoretical temperature and initial temperature, and determine the measured temperature rise based on the equilibrium temperature and initial temperature; determine the deviation value based on the theoretical temperature rise and the measured temperature rise. Obtain the standard deviation value and compare the deviation value with the standard deviation value to determine whether the refrigerant radiator is qualified.

2. The air conditioning device according to claim 1, characterized in that, The total losses of the power module include IGBT conduction losses, diode conduction losses, IGBT switching losses, and diode switching losses, all determined based on the IGBT's relative zero temperature coefficient parameters.

3. The air conditioning device according to claim 2, characterized in that, The control module is configured as follows: Determine the IGBT saturation voltage drop at relative zero temperature coefficient, the diode freewheeling current at relative zero temperature coefficient, and the diode forward voltage drop at relative zero temperature coefficient current based on the IGBT relative zero temperature coefficient current. IGBT conduction losses are determined based on the IGBT's relative zero temperature coefficient current and IGBT's relative zero temperature coefficient saturation voltage drop. The diode conduction loss is determined based on the diode freewheeling current value under IGBT relative zero temperature coefficient current and the diode forward voltage drop under IGBT relative zero temperature coefficient current.

4. The air conditioning device according to claim 3, characterized in that, The control module is configured as follows: Obtain the switching frequency and duty cycle of the power module; IGBT conduction losses are determined based on IGBT relative zero temperature coefficient current, IGBT relative zero temperature coefficient saturation voltage drop, switching frequency, and conduction duty cycle. The diode conduction loss is determined based on the diode freewheeling current value under IGBT relative zero temperature coefficient current, the diode forward conduction voltage drop under IGBT relative zero temperature coefficient current, the switching frequency, and the conduction duty cycle.

5. The air conditioning device according to claim 4, characterized in that, IGBT conduction loss = switching frequency * IGBT relative zero temperature coefficient current * IGBT relative zero temperature coefficient saturation voltage drop; Diode conduction loss = switching frequency * (1 - conduction duty cycle) * diode freewheeling current value based on IGBT relative zero temperature coefficient current * diode forward voltage drop based on IGBT relative zero temperature coefficient current.

6. The air conditioning device according to claim 2, characterized in that, The air conditioning unit includes: The storage module is used to store the correlation between IGBT switching losses and current at several temperatures, and to store the correlation between diode switching losses and current at several temperatures. The control module is configured to determine the IGBT switching losses and diode switching losses based on the IGBT's relative zero temperature coefficient current, equilibrium temperature, and the storage module.

7. The air conditioning device according to claim 1, characterized in that, The thermal resistance of the frequency converter driver is determined by the thermal resistance curve at the equilibrium temperature, and the thermal resistance of the refrigerant radiator is the standard thermal resistance of a qualified refrigerant radiator that has been determined in advance.

8. The air conditioning device according to claim 1, characterized in that, The equilibrium temperature is the temperature at which the real-time temperature detected by the temperature detection module remains constant within a set time period.

9. The air conditioning device according to claim 1, characterized in that, The control module is configured to acquire a predetermined target compressor frequency, control the compressor's operating frequency to reach the target compressor frequency, and then control the compressor's operating state so that the IGBT output current is a relative zero temperature coefficient current.

10. The air conditioning device according to claim 1, characterized in that, The control module is configured to determine the theoretical temperature by multiplying the thermal resistance by the total loss.

Images