Heat dissipation link diagnosis method and system for converter power module

Abstract

A heat dissipation link diagnosis method and system for a converter power module. The method comprises: acquiring a real-time temperature and a reference temperature of a converter power module; on the basis of the real-time temperature of the converter power module, obtaining a first temperature change curve by means of actual measurement; on the basis of the reference temperature of the converter power module, obtaining a second temperature change curve by means of calculation; and comparing the first temperature change curve with the second temperature change curve, so as to diagnose whether a heat dissipation link of the converter power module is abnormal.

Description

A heat dissipation link diagnosis method and system of a converter power module

[0001] Cross-reference to Related Applications

[0002] The present disclosure claims priority to Chinese Patent Application CN202411323631.7 entitled "A heat dissipation link diagnosis method and system of a converter power module" filed on September 23, 2024, the entire contents of which are incorporated by reference into the present disclosure. TECHNICAL FIELD

[0003] The present disclosure relates to the field of power electronics, in particular to a heat dissipation link diagnosis method and system of a converter power module. BACKGROUND

[0004] As a core component of a converter, a power module needs to effectively dissipate heat to transfer heat from the power module to the surrounding environment due to its high heat flux. When the power module dissipates heat abnormally, it will affect the reliable operation of the power module and even cause failure, thereby affecting the safe and stable operation of the converter. Therefore, ensuring that the power module efficiently transfers heat to the environment and discovering the abnormal heat dissipation problem of the power module in advance to ensure the service life of the power module and the safe and stable operation of the converter have become problems to be solved in the current converter technology.

[0005] SUMMARY

[0006] In order to solve the above technical problems or at least partially solve the above technical problems, the present disclosure provides a heat dissipation link diagnosis method and system of a converter power module.

[0007] In a first aspect, the present disclosure provides a heat dissipation link diagnosis method of a converter power module, comprising:

[0008] obtaining a real-time temperature and a reference temperature of the converter power module;

[0009] obtaining a first temperature change curve based on the real-time temperature of the converter power module;

[0010] obtaining a second temperature change curve based on the reference temperature of the converter power module;

[0011] comparing the first temperature change curve and the second temperature change curve to diagnose whether the heat dissipation link of the converter power module is abnormal.

[0012] In some embodiments, the reference temperature of the converter power module is used to obtain the second temperature change curve, comprising:

[0013] obtaining the loss of each power module under actual operating conditions based on operating state data of the converter;

[0014] The temperature of the power module when the power module heat dissipation link is normal is calculated based on the loss of each power module under the actual operating condition and the reference temperature of the power module of the converter.

[0015] The second temperature change curve is obtained based on the temperature of the power module when the power module heat dissipation link is normal.

[0016] In some embodiments, the loss of each power module under the actual operating condition is obtained based on the operating state data of the converter, including:

[0017] The conduction loss of the IGBT and the diode is calculated based on the operating state data of the converter, respectively.

[0018] The switching loss of the IGBT and the diode is calculated based on the operating state data of the converter, respectively.

[0019] The loss of each power module under the actual operating condition is obtained based on the conduction loss and / or the switching loss of the IGBT and the diode; wherein each power module comprises at least one IGBT and at least one diode.

[0020] In some embodiments, the calculation formula of the conduction loss of the IGBT and the diode is expressed as a function of the load current I, the modulation ratio m, the phase difference between the voltage and the current , the input voltage Vin, the output voltage Vout, the boost inductance L and the switching frequency fw.

[0021] In some embodiments, the switching loss of the IGBT and the diode is calculated based on the operating state data of the converter, respectively, including:

[0022] The calculation formula of the switching loss of the IGBT and the diode is expressed as a function of the DC bus voltage Vdc, the load current I, the modulation ratio m, the phase difference between the voltage and the current , the input voltage Vin, the output voltage Vout, the boost inductance L and the switching frequency fw.

[0023] In some embodiments, the temperature of the power module when the power module heat dissipation link is normal is calculated based on the loss of each power module under the actual operating condition and the reference temperature of the power module of the converter, including:

[0024] A predetermined number of power modules of the converter are selected, and the reference temperature of the selected power module of the converter is taken as the initial temperature.

[0025] The coupling thermal impedance parameters of the power module are obtained based on the initial temperature of a predetermined number of power modules of the converter and the loss under the actual operating condition, and based on a relationship model between the temperature of the power module and the coupling thermal impedance, which is obtained through testing or simulation;

[0026] The relationship model between the temperature of the power module and the coupling thermal impedance is reconstructed based on the coupling thermal impedance parameters of the power module.

[0027] The loss of each power module under the actual operating condition and the reference temperature of the power module of the converter are substituted into the reconstructed relationship model between the temperature of the power module and the coupling thermal impedance to obtain the temperature of the power module when the heat dissipation link of the power module is normal.

[0028] In some embodiments, the temperature change first curve and the temperature change second curve are compared to diagnose whether the heat dissipation link of the power module of the converter is abnormal, including:

[0029] The temperature change second curve is multiplied by a preset coefficient, or the temperature change second curve is added by a preset temperature threshold to obtain an improved temperature change second curve;

[0030] In a case where the value of the temperature change first curve is greater than the value of the improved temperature change second curve, it is determined that the heat dissipation link of the power module of the converter is abnormal;

[0031] In a case where the value of the temperature change first curve is less than or equal to the value of the improved temperature change second curve, it is determined that the heat dissipation link of the power module of the converter is normal.

[0032] In the second aspect, the disclosure provides a heat dissipation link diagnosis system of a power module of a converter, including a temperature detection unit, a temperature measurement unit, a temperature calculation unit and a temperature diagnosis unit.

[0033] The temperature detection unit is configured to obtain the real-time temperature and the reference temperature of the power module of the converter.

[0034] The temperature measurement unit is configured to obtain a temperature change first curve based on the real-time temperature of the power module of the converter.

[0035] The temperature calculation unit is configured to obtain a temperature change second curve based on the reference temperature of the power module of the converter.

[0036] The temperature diagnosis unit is configured to compare the temperature change first curve and the temperature change second curve to diagnose whether the heat dissipation link of the power module of the converter is abnormal. In some embodiments, the temperature detection unit includes a power module internal temperature detection unit and a radiator inlet temperature detection unit.

[0037] The power module internal temperature detection unit is configured to obtain the real-time temperature of the power module of the converter.

[0038] a radiator inlet temperature detection unit for obtaining a reference temperature of the power module of the converter.

[0039] In some embodiments, the radiator inlet temperature detection unit comprises an air inlet temperature detection unit and / or a liquid inlet temperature detection unit;

[0040] the air inlet temperature detection unit is configured to detect the air temperature at the air inlet of the air-cooled radiator;

[0041] the liquid inlet temperature detection unit is configured to detect the cooling medium temperature at the liquid inlet of the liquid-cooled radiator.

[0042] In a third aspect, the present disclosure also provides a computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements any of the above methods.

[0043] In a fourth aspect, the present disclosure also provides a computer program product comprising computer programs / instructions, wherein the computer programs, when executed by a processor, implement any of the above methods. BRIEF DESCRIPTION OF DRAWINGS

[0044] FIG. 1 is a flowchart of a method for diagnosing a thermal link of a power module of a converter according to an embodiment of the present disclosure;

[0045] FIG. 2 is a flowchart of a method for diagnosing a thermal link of a power module of a converter according to an embodiment of the present disclosure;

[0046] FIG. 3 is a distribution diagram of a power module of a converter according to an embodiment of the present disclosure;

[0047] FIG. 4 is a block diagram of a system for diagnosing a thermal link of a power module of a converter according to an embodiment of the present disclosure;

[0048] FIG. 5 is a three-dimensional view of a converter with an air-cooled power module according to an embodiment of the present disclosure;

[0049] FIG. 6 is a side view of an air-cooled converter according to an embodiment of the present disclosure;

[0050] FIG. 7 is a three-dimensional view of a power module cooling system of an air-cooled converter according to an embodiment of the present disclosure;

[0051] FIG. 8 is a three-dimensional view of a converter with a liquid-cooled power module according to an embodiment of the present disclosure;

[0052] FIG. 9 is a side view of a liquid-cooled converter according to an embodiment of the present disclosure;

[0053] FIG. 10 is a three-dimensional view of a power module cooling system of a liquid-cooled converter according to an embodiment of the present disclosure.

[0054] Reference signs: 1) air-cooled converter-7, converter front cabinet, 8, power module, 9, interface material, 10, air-cooled radiator, 11, cooling fan, 12, radiator inlet temperature detection unit, 2) liquid-cooled converter-13, converter front cabinet, 14, power module, 15, interface material, 16, liquid-cooled radiator, 17, liquid inlet, 18, liquid outlet, and 19, radiator liquid inlet temperature detection unit. DETAILED DESCRIPTION

[0055] In order to enable a person skilled in the art to better understand the technical solutions of the present disclosure, and to fully understand and implement the implementation process of the present disclosure how to apply technical means to solve technical problems and achieve corresponding technical effects, the technical solutions in the embodiments of the present disclosure will be described clearly and completely in conjunction with the drawings in the embodiments of the present disclosure. Obviously, the described embodiments are only a part of the embodiments of the present disclosure, not all embodiments. The embodiments of the present disclosure and various features in the embodiments can be combined with each other without conflict, and the technical solutions formed thereby are all within the protection scope of the present disclosure. Based on the embodiments in the present disclosure, all other embodiments obtained by a person skilled in the art without creative labor should be within the protection scope of the present disclosure.

[0056] It should be noted that the terms "first", "second", and the like in the specification and claims of the present disclosure and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or a chronological sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present disclosure described herein can be implemented in an order other than those illustrated or described herein. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0057] It should be noted that the steps shown in the flowchart of the drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown herein.

[0058] Fig. 1 shows a flowchart of a converter power module thermal link diagnostic method according to an embodiment of the present disclosure. Real-time temperature data and reference temperature data of the power module are collected by a temperature detection unit. A measured power module temperature value is obtained based on the real-time temperature data, and a calculated power module temperature value is obtained based on the reference temperature data. The measured power module temperature value and the calculated power module temperature value are compared to obtain a temperature difference value, to determine whether the power module thermal link cooling is abnormal. If it is abnormal, the power module output power is reduced and power module cooling link abnormal alarm information is output. For an air-cooled converter, the reference temperature is the air temperature at the inlet of the radiator. For a liquid-cooled converter, the reference temperature is the cooling medium temperature at the inlet of the radiator. The circuit of the converter power module can be different circuit topologies including DC-DC, DC-AC, AC-DC, and AC-AC conversion. The type and number of converter power module circuit topologies are not specifically limited in the present disclosure.

[0059] Fig. 2 is a flowchart of a converter power module cooling link diagnostic method according to an embodiment of the present disclosure. As shown in Fig. 2, a converter power module cooling link diagnostic method includes the following steps S201 to S204.

[0060] S201, obtaining real-time temperature and reference temperature of the converter power module.

[0061] S202, obtaining a first temperature change curve based on the real-time temperature of the converter power module.

[0062] S203, obtaining a second temperature change curve based on the reference temperature of the converter power module.

[0063] S204, comparing the first temperature change curve and the second temperature change curve to diagnose whether the cooling link of the converter power module is abnormal.

[0064] Compared with the prior art, in the technical solution of the present disclosure, a measured power module temperature value is obtained based on real-time temperature data, and a calculated power module temperature value is obtained based on reference temperature data. The measured power module temperature value and the calculated power module temperature value are compared to obtain a temperature difference value, to determine whether the power module thermal link cooling is abnormal. If it is abnormal, the power module output power is reduced and power module cooling link abnormal alarm information is output. This avoids the failure of the power module due to abnormal cooling, ensures efficient transfer of heat from the power module to the environment, and early detection of power module thermal link cooling abnormality, thereby ensuring the service life of the power module and safe and stable operation of the converter.

[0065] The converter provided by the present disclosure can be composed of two different types of radiators (air-cooled radiator or liquid-cooled radiator), and thus is divided into an air-cooled converter and a liquid-cooled converter.

[0066] On the basis of the above-mentioned embodiments, the reference temperature of the power module of the converter is calculated to obtain a second temperature change curve, comprising:

[0067] Based on the operating state data of the converter, the loss of each power module under the actual operating condition is obtained.

[0068] Based on the loss of each power module under the actual operating condition and the reference temperature of the power module of the converter, the temperature of the power module when the heat dissipation link of the power module is normal is calculated.

[0069] Based on the temperature of the power module when the heat dissipation link of the power module is normal, the second temperature change curve is obtained.

[0070] On the basis of the above-mentioned embodiments, based on the operating state data of the converter, the loss of each power module under the actual operating condition is obtained, comprising:

[0071] Based on the operating state data of the converter, the conduction loss of the IGBT and the diode is calculated respectively.

[0072] Based on the operating state data of the converter, the switching loss of the IGBT and the diode is calculated respectively.

[0073] Based on the conduction loss and / or the switching loss of the IGBT and the diode, the loss of each power module under the actual operating condition is obtained; wherein each power module comprises at least one IGBT and at least one diode.

[0074] At present, there are mature algorithms for the loss of power devices under different DC / AC and AC / DC main circuit topologies, which can be borrowed. Based on the static characteristic curve of the power module and the actual main circuit test dynamic characteristic curve parameters, the average total loss of the power module in an output period can be calculated according to the operating principle of the converter.

[0075] The loss of the IGBT includes conduction loss and switching loss. The conduction loss of the IGBT is related to the inverter working modulation strategy, the load current I, the modulation ratio m, the phase difference φ between voltage and current, and the like, and is as follows:

[0076] The switching loss of the IGBT includes turn-on loss and turn-off loss. The size of the switching loss of the IGBT is related to the inverter working modulation strategy, the DC bus voltage Vdc, the load current I, the modulation ratio m, the phase difference φ between voltage and current, and the switching frequency fw, and is as follows:

[0077] The total loss of the IGBT can be expressed as follows: IGBT P cond(T) +P sw(T)(3)

[0078] The loss calculation method of the diode is almost the same as that of the IGBT. The conduction loss of the diode is related to the inverter working modulation strategy, the load current I, the modulation ratio m, and the phase difference φ between the voltage and the current, and can be expressed as follows:

[0079] For the diode, the turn-on loss can be ignored, and only the diode reverse recovery loss is calculated, which is related to the inverter working modulation strategy, the DC bus voltage Vdc, the load current I, the modulation ratio m, the phase difference φ between the voltage and the current, and the switching frequency fw, and can be expressed as follows:

[0080] The total loss of the diode can be expressed as follows: P Diode = P cond(D) + P sw(D) (6)

[0081] The total loss of the power module device can be expressed as: P All = P IGBT + P Diode (7)

[0082] For a power module composed of multiple IGBT devices, the losses of the individual IGBT devices can be calculated, and the losses of the power module of each bridge arm are obtained by taking the sum.

[0083] Similarly, for the power device loss of the conventional DC / DC converter main circuit topology, there is a mature algorithm that can be used. Based on the static characteristic curve of the power device and the actual main circuit test dynamic characteristic curve parameters, the average total loss of the power module can be calculated according to the main circuit parameters and the operation principle of the DC / DC converter. Taking a Boost converter as an example:

[0084] The loss of the IGBT includes conduction loss and switching loss. The conduction loss of the IGBT is related to the load current I, the ripple current ΔI, the input voltage Vin, and the output voltage Vout. Among them, ΔI can be expressed as a function of the boost inductance L, the input voltage Vin, the output voltage Vout, and the switching frequency fw. The conduction loss of the IGBT can be expressed as a function of the load current I, the input voltage Vin, the output voltage Vout, the boost inductance L, and the switching frequency fw: P cond(T) = f5(I, Vin, Vout, L, fw) (8)

[0085] The IGBT switching loss includes turn-on loss and turn-off loss. The IGBT switching loss is related to load current I, ripple current ΔI, input voltage Vin and output voltage Vout, and can also be expressed as a function of load current I, input voltage Vin, output voltage Vout, boost inductance L and switching frequency fw: P sw(T) = f6(I, Vin, Vout, L, fw) (9)

[0086] The total loss of the IGBT can be expressed as: P IGBT = P cond(T) + P sw(T) (10)

[0087] The loss calculation method of the diode is almost the same as that of the IGBT. The conduction loss and switching loss of the diode can also be expressed as a function of load current I, input voltage Vin, output voltage Vout, boost inductance L and switching frequency fw: P cond(D) = f7(I, Vin, Vout, L, fw) (11) P sw(D) = f8(I, Vin, Vout, L, fw) (12)

[0088] The total loss of the diode can be expressed as: P Diode = P cond(D) + P sw(D) (13)

[0089] The total loss of the power module device can be expressed as: P All = P IGBT + P Diode (14)

[0090] For a power module composed of multiple IGBT devices, the loss of each IGBT device can be calculated, and the loss of the power module of each bridge arm is obtained by taking the sum.

[0091] On the basis of the above embodiment, the calculation formula of the conduction loss of the IGBT and the diode is expressed as a function of load current I, modulation ratio m, phase difference between voltage and current.

[0092] It should be noted that the loss calculation of power devices under different DC / AC and AC / DC main circuit topologies, the calculation formula of the conduction loss of the IGBT and the diode can be expressed as:

[0093] where T and D represent IGBT and diode respectively, I is load current, m is modulation ratio, is the phase difference between voltage and current, where f1 and f3 are related to the working modulation strategy of inverter, and are the sum of polynomials only related to fw, I, m, and Vdc.

[0094] Alternatively, on the basis of the above embodiment, the calculation formula of the conduction loss of IGBT and diode is expressed as a function of load current I, input voltage Vin, output voltage Vout, boost inductance L and switching frequency fw.

[0095] It should be noted that the loss of power devices under the topology of conventional DC / DC converter main circuit, the calculation formula of the conduction loss of IGBT and diode can be expressed as: cond(T) P cond(D) = f7(I, Vin, Vout, L, fw).

[0096] On the basis of the above embodiment, the switching loss of IGBT and diode is calculated based on the operating state data of the converter, including:

[0097] The calculation formula of the switching loss of IGBT and diode is expressed as a function of DC bus voltage Vdc, load current I, modulation ratio m, phase difference between voltage and current and switching frequency fw.

[0098] It should be noted that the loss calculation of power devices under different DC / AC and AC / DC main circuit topologies, the calculation formula of the switching loss of IGBT and diode can be expressed as:

[0099] where T and D represent IGBT and diode respectively, Vdc is DC bus voltage, I is load current, m is modulation ratio, is the phase difference between voltage and current, fw is the switching frequency, where f2 and f4 are related to the working modulation strategy of inverter, and are the sum of polynomials only related to fw, I, m, and Vdc.

[0100] Alternatively, on the basis of the above embodiment, the calculation formula of the switching loss of IGBT and diode is expressed as a function of load current I, input voltage Vin, output voltage Vout, boost inductance L and switching frequency fw.

[0101] It should be noted that the loss of the power device under the conventional DC / DC converter main circuit topology, the switching loss of IGBT and diode can be respectively expressed as: P sw(T) = f6(I, Vin, Vout, L, fw); P sw(D) = f8(I, Vin, Vout, L, fw).

[0102] On the basis of the above embodiment, the temperature of the power module under normal conditions of the power module heat dissipation link is calculated based on the loss of each power module under the actual operating condition and the reference temperature of the converter power module. The specific process is described as follows.

[0103] First, a predetermined number of converter power modules are selected, and the reference temperature of the selected converter power module is taken as the initial temperature.

[0104] Secondly, based on the initial temperature of the selected predetermined number of converter power modules and the loss under the actual operating condition, and based on the relationship model of the temperature of the power module and the coupled thermal impedance, the coupled thermal impedance parameters of the power module are obtained by test or simulation.

[0105] Figure 3 shows a power module distribution diagram of one embodiment of the present disclosure. Taking a converter with 6 power modules as an example, the temperatures T1(t), T2(t), T3(t), T4(t), T5(t), T6(t) of the power modules 1, 2, 3, 4, 5, 6 are given by formula (15), where P1(t), P2(t), P3(t), P4(t), P5(t), P6(t) are the real-time losses of the power modules 1, 2, 3, 4, 5, 6, respectively, Ta is the reference temperature, T01, T02, T03, T04, T05, T06 are the initial temperatures of the power modules 1, 2, 3, 4, 5, 6, respectively, T0a is the initial temperature of the reference temperature, Z11(t), Z21(t), Z31(t), Z41(t), Z51(t), Z61(t) are the coupling thermal impedances generated by the power module 1 to the power modules 1, 2, 3, 4, 5, 6, respectively, Z12(t), Z22(t), Z32(t), Z42(t), Z52(t), Z62(t) are the coupling thermal impedances generated by the power module 2 to the power modules 1, 2, 3, 4, 5, 6, respectively, Z13(t), Z23(t), Z33(t), Z43(t), Z53(t), Z63(t) are the coupling thermal impedances generated by the power module 3 to the power modules 1, 2, 3, 4, 5, 6, respectively, Z14(t), Z24(t), Z34(t), Z44(t), Z54(t), Z64(t) are the coupling thermal impedances generated by the power module 4 to the power modules 1, 2, 3, 4, 5, 6, respectively, Z15(t), Z25(t), Z35(t), Z45(t), Z55(t), Z55(t) are the coupling thermal impedances generated by the power module 5 to the power modules 1, 2, 3, 4, 5, 6, respectively, and Z16(t), Z26(t), Z36(t), Z46(t), Z56(t), Z66(t) are the coupling thermal impedances generated by the power module to the power module 6 to the power modules 1, 2, 3, 4, 5, 6, respectively. The initial temperatures of the 6 power modules are consistent with the reference temperature, i.e., T01, T02, T03, T04, T05, T06 are equal to T0a. The coupling thermal impedance parameters of the power modules can be obtained by experiments or simulations.

[0106] Again, the temperature and coupling thermal impedance relationship model of the power module is reconstructed based on the coupling thermal impedance parameters of the power module.

[0107] Specifically, the power module 1 loss is P1(t), the remaining power module loss is 0, the reference temperature Ta is a stable value, the temperatures T1(t), T2(t), T3(t), T4(t), T5(t), T6(t) of the power modules 1, 2, 3, 4, 5, 6 are calculated by formula (15), Z11(t), Z21(t), Z31(t), Z41(t), Z51(t), Z61(t) are calculated, R11 is the steady-state thermal resistance corresponding to the thermal impedance of the power module 1 (the thermal resistance value is equal to the temperature difference after thermal equilibrium divided by the applied steady-state power), and the coupling thermal impedance of the remaining power modules is obtained in the same way as the coupling thermal impedance of the power module 1.

[0108] Finally, the loss of each power module under actual operating conditions and the reference temperature of the power converter power module are substituted into the reconstructed temperature and coupling thermal impedance relationship model of the power module to obtain the temperature of the power module when the power module heat dissipation link is normal.

[0109] For example, the loss of each power module under actual operating conditions is obtained by the power module loss calculation method, and the loss and reference temperature of each power module are substituted into formula (15) to calculate the temperatures T1(t), T2(t), T3(t), T4(t), T5(t), T6(t) of the power modules 1, 2, 3, 4, 5, 6 when the power module heat dissipation link is normal. When the measured temperature is greater than the calculated temperature, it is considered that the power module heat dissipation link is abnormal.

[0110] On the basis of the above embodiment, the temperature change first curve is compared with the temperature change second curve to diagnose whether the heat dissipation link of the power converter power module is abnormal. The specific process is as follows.

[0111] The temperature change second curve is multiplied by a preset coefficient, or the temperature change second curve is added to a preset temperature threshold to obtain an improved temperature change second curve.

[0112] In the case where the value of the temperature change first curve is greater than the value of the improved temperature change second curve, it is determined that the heat dissipation link of the power converter power module is abnormal.

[0113] In the case where the value of the temperature change first curve is less than or equal to the value of the improved temperature change second curve, it is determined that the heat dissipation link of the power converter power module is not abnormal.

[0114] It is explained here that the value of the first temperature change curve and the value of the second temperature change curve are the average values of all values on the respective curves.

[0115] In actual application, a certain temperature difference allowance should be considered, for example, multiplying the calculated value of the power module temperature by 1.1 times (the coefficient is determined according to the consistency control ability of mass production) or adding a fixed value (the allowance is determined according to the consistency control ability of mass production) such as 5℃ to the calculated value of the power module temperature. When the converter is in actual operation, the power module and reference temperature data are collected by the temperature detection unit, and the temperature value of the power module when the power module heat dissipation link is normal is calculated. When the measured temperature value of the power module is greater than the calculated temperature value of the power module, it can be considered that the power module heat dissipation link is abnormal.

[0116] In other words, the temperature of the power module (with an NTC inside) and the reference temperature are collected in real time by the temperature detection unit, the real-time temperature curve of the power module is obtained, the loss of the power module in the converter is obtained through the running state data (input voltage, bus voltage, output voltage, output current, power factor, etc.) of the converter through calculation or table lookup, and the thermal impedance of the heat dissipation link of the power module is extracted through simulation or test. According to the real-time loss and thermal impedance of the power module in the converter, the temperature rise change curve between the power module in the converter and the reference temperature can be calculated, and the reference temperature is added to obtain the calculated real-time temperature change curve of the power module in the converter. The measured temperature change curve and the calculated temperature change curve of the power module are compared, and when the measured temperature change curve is greater than the calculated temperature change curve of the power module plus a preset temperature difference threshold (considering the dispersion of devices, the dispersion of processes and aging), it can be confirmed that the heat dissipation link of the power module is abnormal, which is used for diagnosing the heat dissipation link of the power module of the converter.

[0117] Fig. 4 is a block diagram of a heat dissipation link diagnosis system of a power module of a converter provided by an embodiment of the present disclosure. As shown in Fig. 4, the heat dissipation link diagnosis system of the power module of the converter includes a temperature detection unit 401, a temperature measurement unit 402, a temperature calculation unit 403 and a temperature diagnosis unit 404.

[0118] The temperature detection unit 401 is configured to obtain the real-time temperature and the reference temperature of the power module of the converter.

[0119] The temperature measurement unit 402 is configured to obtain a first temperature change curve based on the real-time temperature measurement of the power module of the converter.

[0120] The temperature calculation unit 403 is configured to obtain a second temperature change curve based on the reference temperature calculation of the power module of the converter.

[0121] The temperature diagnosis unit 404 is configured to compare the temperature change first curve with the temperature change second curve to diagnose whether the heat dissipation link of the power module of the converter is abnormal.

[0122] Compared with the prior art, in the technical solution of the present disclosure, the measured power module temperature value is obtained based on real-time temperature data, and the calculated power module temperature value is obtained based on reference temperature data. The measured power module temperature value and the calculated power module temperature value are compared to obtain a temperature difference value to determine whether the heat dissipation of the power module heat link is abnormal. If it is abnormal, the output power of the power module is reduced, and power module heat dissipation link abnormal alarm information is output. This avoids the failure of the power module due to abnormal heat dissipation, ensures that the power module efficiently transfers heat to the environment, and discovers the abnormal heat dissipation problem of the power module heat link in advance, thereby ensuring the service life of the power module and the safe and stable operation of the converter.

[0123] On the basis of the above-mentioned embodiments, the temperature detection unit comprises a power module internal temperature detection unit and a radiator inlet temperature detection unit;

[0124] The power module internal temperature detection unit is configured to obtain the real-time temperature of the power module of the converter.

[0125] The radiator inlet temperature detection unit is configured to obtain the reference temperature of the power module of the converter.

[0126] On the basis of the above-mentioned embodiments, the radiator inlet temperature detection unit comprises an air inlet temperature detection unit and / or a liquid inlet temperature detection unit.

[0127] The air inlet temperature detection unit is configured to detect the air temperature at the air inlet of the air-cooled radiator.

[0128] The liquid inlet temperature detection unit is configured to detect the cooling medium temperature at the liquid inlet of the liquid-cooled radiator.

[0129] The following will be described in detail with respect to air-cooled converters and liquid-cooled converters. For the air-cooled converter, the reference temperature is the air temperature at the air inlet of the radiator. For the liquid-cooled converter, the reference temperature is the cooling medium temperature at the liquid inlet of the radiator.

[0130] 1) Air-cooled converter

[0131] Figure 5 is a three-dimensional view of a converter with air-cooled power modules, Figure 6 is a side view of the air-cooled converter of Figure 5, and Figure 7 is a three-dimensional view of the power module cooling system of the air-cooled converter of Figure 5. The air-cooled converter is composed of a converter front cabinet 7, a power module 8, an interface material 9, an air-cooled radiator 10, a radiator fan 11, and a radiator inlet temperature detection unit 12. The converter front cabinet 7 includes a sampling control unit for collecting and processing temperature sensor data and determining whether the power module thermal link cooling is abnormal. If the power module thermal link is abnormal, the sampling control unit controls the power output of the power module and outputs corresponding cooling abnormality warning information. The power module 8 is internally integrated with at least one power module temperature detection unit, which can be a temperature detection device such as a thermistor, for detecting the temperature of the power module. The power module 8 conducts heat to the air-cooled radiator 10 through the interface material 9, and transfers heat to the external environment through the radiator fan 11. The air-cooled radiator 10 is composed of a base plate 101 and fins 102. The radiator inlet temperature detection unit 12 is used to detect the air temperature at the inlet of the radiator and is located on the side of the radiator inlet. If the radiator fan is a blowing fan, the position of the radiator inlet temperature detection unit is shown in Figure 6. If the radiator fan is an exhaust fan, cold air first passes through the radiator and then passes through the radiator fan. If the radiator fan is located above the radiator for back inlet cooling, the radiator inlet temperature detection unit is located on the side of the radiator inlet. The temperature detection unit can be a temperature detection device such as a thermistor. If there is only one radiator inlet temperature detection unit 12, the temperature of the detection unit is the air temperature at the inlet of the radiator. If there are multiple radiator inlet temperature detection units 12, the average, median, or other statistical value of the temperatures of the multiple radiator inlet temperature detection units is determined as the air temperature at the inlet of the radiator.

[0132] The temperature T7 of the power module is measured by the internally integrated temperature detection unit of the power module 8, the air temperature T8 at the inlet of the radiator is obtained by the radiator inlet temperature detection unit 12, and the temperature value T9 of the power module when the power module cooling link is normal is calculated from the air temperature T8 at the inlet of the radiator (a certain temperature difference allowance has been considered). When the measured temperature value T7 of the power module is greater than the calculated temperature value T9 of the power module, it can be considered that the power module cooling link is abnormal. The sampling control unit of the converter front cabinet 7 determines that the power module cooling link is abnormal, reduces the output power of the power module, and outputs power module cooling link abnormality warning information. The power module cooling abnormality is caused by cooling abnormality in at least one of the power module body, the interface material, the air-cooled radiator, and the radiator fan.

[0133] 2) Liquid-cooled converter

[0134] Figure 8 is a three-dimensional view of a converter with a liquid-cooled heat dissipation power module, Figure 9 is a side view of the liquid-cooled converter of Figure 8, and Figure 10 is a three-dimensional view of the power module heat dissipation system of the liquid-cooled converter of Figure 8. The liquid-cooled converter is composed of a converter front cabinet 13, a power module 14, an interface material 15, a liquid-cooled heat sink 16, a liquid inlet 17, a liquid outlet 18, and a liquid inlet temperature detection unit 19. The converter front cabinet 13 includes a sampling control unit for collecting and processing temperature sensor temperature data and determining whether the power module thermal link is abnormal. If the power module thermal link is abnormal, the sampling control unit controls the power output of the power module and outputs corresponding heat dissipation abnormality warning information. The power module 14 is internally integrated with at least one power module temperature detection unit, which can be a temperature detection device such as a thermistor, for detecting the temperature of the power module. The power module 14 conducts heat to the liquid-cooled heat sink 16 through the interface material 15, and the heat is transferred away from the liquid-cooled heat sink 16 by a cooling medium. The cooling medium of the liquid-cooled heat sink 16 flows into the heat sink through the liquid inlet 17, and the cooling liquid absorbs heat and flows out from the liquid outlet 18. The liquid inlet temperature detection unit 19 is used to collect the temperature of the cooling medium at the liquid inlet of the liquid-cooled heat sink, which can be a temperature detection device such as a thermistor.

[0135] The power module 14 obtains the temperature T10 of the power module through the internally integrated temperature detection unit, the temperature T11 of the cooling medium at the liquid inlet of the liquid-cooled heat sink is obtained by the liquid inlet temperature detection unit 19, and the temperature value T12 of the power module when the power module heat dissipation link is normal is calculated from the temperature T11 of the cooling medium at the liquid inlet of the liquid-cooled heat sink (a certain temperature difference allowance has been considered). When the measured temperature value T10 of the power module is greater than the calculated temperature value T12 of the power module, it can be considered that the power module heat dissipation link is abnormal. The sampling control unit of the converter front cabinet 13 determines that the power module heat dissipation link is abnormal, reduces the output power of the power module, and outputs power module heat dissipation link abnormality warning information. The power module heat dissipation abnormality is caused by heat dissipation abnormality at at least one of the power module body, the interface material, and the liquid-cooled heat sink.

[0136] Reducing the power output of the power module can reduce the temperature of the power module with abnormal power module heat dissipation link, ensuring the safety of the converter. Methods for reducing the power output of the power module include:

[0137] (1) Reducing the real-time output power P of the power module to a derated output power P1. After the power is reduced, the loss of the power module will decrease, thereby reducing the temperature of the power module to within a safe range;

[0138] (2) Reducing the output power of the power module according to the degree of deviation of the measured temperature value of the power module from the calculated temperature value of the power module. The greater the deviation, the greater the power reduction. The relationship between the deviation and the power reduction is not specifically limited in this application.

[0139] On the basis of the above-mentioned embodiments, the embodiments of the present disclosure further provide a computer readable storage medium, which stores a computer program, wherein the computer program is executed by a processor to implement the steps of the method of the above-mentioned aspects.

[0140] On the basis of the above-mentioned embodiments, the embodiments of the present disclosure further provide a computer program product, which comprises computer programs / instructions, wherein the computer programs are executed by a processor to implement the steps of the method of the above-mentioned aspects.

[0141] The computer readable storage medium can be implemented by any type of volatile or non-volatile storage devices or a combination thereof, and the computer readable storage medium can include, but is not limited to, for example, random access memory (RAM), read only memory (ROM), flash memory, EPROM memory, EEPROM memory, registers, computer storage media (such as a hard disk, a floppy disk, a solid state disk, a removable disk, a CD-ROM, a DVD-ROM, a Blu-ray disc, etc.).

[0142] The computer readable storage medium can also store at least one computer executable program / instruction, such as computer readable instructions. The computer readable storage medium includes, but is not limited to, for example, volatile memory and / or non-volatile memory. The volatile memory may, for example, include random access memory (RAM) and / or cache memory, etc. The computer readable storage medium may, for example, include read only memory (ROM), a hard disk, a flash memory, etc. For example, the non-transitory computer readable storage medium can be connected to a computing device such as a computer, and then, in the case where the computing device runs the computer readable instructions stored on the computer readable storage medium, the various methods as described above can be performed.

[0143] In addition, the computer device can also include (but not limited to) a data bus, an input / output (I / O) bus, a display, and an input / output device (such as a keyboard, a mouse, a speaker, etc.), etc.

[0144] The processor can communicate with external devices via a wired or wireless network through the I / O bus.

[0145] In one embodiment, the at least one computer executable instruction can also be compiled or composed into a software product / computer program product, wherein one or more computer executable instructions are executed by the processor to perform the steps of various functions and / or methods in the embodiments described in the present technology.

[0146] In summary, the present disclosure provides a heat dissipation link diagnosis method and system for a converter power module. The method comprises: obtaining a real-time temperature and a reference temperature of the converter power module; obtaining a first temperature change curve based on the real-time temperature of the converter power module; obtaining a second temperature change curve based on the reference temperature of the converter power module; and comparing the first temperature change curve with the second temperature change curve to diagnose whether the heat dissipation link of the converter power module is abnormal. A diagnosis system with the same technical concept is also disclosed, comprising a temperature detection unit, a temperature measurement unit, a temperature calculation unit, and a temperature diagnosis unit. The temperature detection unit is configured to obtain the real-time temperature and the reference temperature of the converter power module. The temperature measurement unit is configured to obtain the first temperature change curve based on the real-time temperature of the converter power module. The temperature calculation unit is configured to obtain the second temperature change curve based on the reference temperature of the converter power module. The temperature diagnosis unit is configured to compare the first temperature change curve with the second temperature change curve to diagnose whether the heat dissipation link of the converter power module is abnormal. The present disclosure obtains a measured power module temperature value based on real-time temperature data and a calculated power module temperature value based on reference temperature data, compares the measured power module temperature value with the calculated power module temperature value to obtain a temperature difference value, judges whether the heat dissipation of the power module is abnormal, avoids the failure of the power module caused by abnormal heat dissipation, ensures efficient heat transfer of the power module to the environment, and discovers the abnormal heat dissipation problem of the power module in advance, thereby ensuring the service life of the power module and the safe and stable operation of the converter.

[0147] In the embodiments of the present disclosure, it should be understood that the disclosed apparatus and method can also be implemented by other means. The apparatus embodiments described above are only schematic, for example, the flowcharts and block diagrams in the drawings show possible implementation architectures, functions and operations of the apparatus, method and computer program product according to the embodiments of the present disclosure. In this regard, each block in the flowcharts or block diagrams can represent a module, a program segment or a part of code, which contains one or more executable instructions for implementing the specified logical function. It should also be noted that in some alternative implementations, the functions noted in the blocks can occur in a different order than that noted in the drawings. For example, two consecutive blocks can actually be executed substantially in parallel, and sometimes they can be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and the combination of blocks in the block diagrams and / or flowcharts, can be implemented by a dedicated hardware-based system for executing the specified functions or actions, or can be implemented by a combination of dedicated hardware and computer instructions.

[0148] It is to be understood that the terminology "including", "comprising", or any other variation thereof, is intended to cover a non-exclusive inclusion such that processes, methods, articles, or apparatuses that comprise a list of elements are not necessarily limited to those elements, but can include other elements not expressly listed or inherent to such processes, methods, articles, or apparatuses. Without limitation, an element preceded by "comprises a" does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0149] Although the disclosed embodiments of the present disclosure are as described above, the above description is only for the purpose of facilitating understanding of the present disclosure and is not intended to limit the present disclosure. Any person skilled in the art of the present disclosure can make any modification and change in the form and details without departing from the spirit and scope of the present disclosure, but the patent protection scope of the present disclosure shall be subject to the scope defined by the appended claims.

Claims

1. A method of diagnosing a thermal link of a power module of a power converter, wherein, The method comprises: obtaining real-time temperature and reference temperature of a power module of a converter; calculating a first temperature change curve based on the real-time temperature of the power module of the converter; calculating a second temperature change curve based on the reference temperature of the power module of the converter; comparing the first temperature change curve with the second temperature change curve to diagnose whether the heat dissipation link of the power module of the converter is abnormal.

2. The diagnostic method of the thermal link of a power converter module according to claim 1, wherein, The calculating of the second temperature change curve based on the reference temperature of the power module of the converter comprises: obtaining the loss of each power module under actual operating conditions based on operating state data of the converter; calculating the temperature of the power module when the heat dissipation link of the power module is normal based on the loss of each power module under actual operating conditions and the reference temperature of the power module of the converter; obtaining the second temperature change curve based on the temperature of the power module when the heat dissipation link of the power module is normal.

3. The diagnostic method of the thermal link of a power converter module according to claim 2, wherein, The obtaining of the loss of each power module under actual operating conditions based on operating state data of the converter comprises: calculating the conduction loss of IGBT and diode respectively based on operating state data of the converter; calculating the switching loss of IGBT and diode respectively based on operating state data of the converter; obtaining the loss of each power module under actual operating conditions based on the conduction loss and / or switching loss of IGBT and diode; wherein each power module comprises at least one IGBT and at least one diode.

4. The diagnostic method of the thermal link of a power converter module according to claim 3, wherein, The calculating of the conduction loss of IGBT and diode respectively based on operating state data of the converter comprises: The calculation formula of the turn-on loss of the IGBT and diode is expressed as load current I, modulation ratio m, phase difference between voltage and current a function of or expressing the calculation formula of the conduction loss of IGBT and diode as a function of load current I, input voltage Vin, output voltage Vout, boost inductance L and switching frequency fw.

5. The diagnostic method of the thermal link of a power converter module according to claim 3, wherein, The calculating of the switching loss of IGBT and diode respectively based on operating state data of the converter comprises: The calculation formula of the switching loss of the IGBT and diode is expressed as the DC bus voltage Vdc, load current I, modulation ratio m, phase difference between voltage and current a function of switching frequency fw or expressing the calculation formula of the switching loss of IGBT and diode as a function of load current I, input voltage Vin, output voltage Vout, boost inductance L and switching frequency fw.

6. The diagnostic method of the thermal link of a power converter module according to claim 2, wherein, The calculating of the temperature of the power module when the heat dissipation link of the power module is normal based on the loss of each power module under actual operating conditions and the reference temperature of the power module of the converter comprises: selecting a predetermined number of power modules of the converter, and taking the reference temperature of the selected power modules of the converter as initial temperature; obtaining the coupling thermal impedance parameter of the power module based on the initial temperature and the loss under actual operating conditions of the selected predetermined number of power modules of the converter, and based on the relationship model between the temperature of the power module and the coupling thermal impedance; reconstructing the relationship model between the temperature of the power module and the coupling thermal impedance based on the coupling thermal impedance parameter of the power module; substituting the loss of each power module under actual operating conditions and the reference temperature of the power module of the converter into the reconstructed relationship model between the temperature of the power module and the coupling thermal impedance to obtain the temperature of the power module when the heat dissipation link of the power module is normal.

7. The diagnostic method of the thermal link of a power converter module according to claim 1, wherein, The comparing the temperature change first curve with the temperature change second curve to diagnose whether the heat dissipation link of the converter power module is abnormal comprises: multiplying the temperature change second curve by a preset coefficient, or adding a preset temperature threshold to the temperature change second curve to obtain an improved temperature change second curve; in the case that the value of the temperature change first curve is greater than the value of the improved temperature change second curve, determining that the heat dissipation link of the converter power module is abnormal; in the case that the value of the temperature change first curve is less than or equal to the value of the improved temperature change second curve, determining that the heat dissipation link of the converter power module is not abnormal.

8. A heat dissipation link diagnosis system of a converter power module, comprising a temperature detection unit, a temperature measurement unit, a temperature calculation unit and a temperature diagnosis unit; wherein, the temperature detection unit is configured to obtain a real-time temperature and a reference temperature of the converter power module; the temperature measurement unit is configured to obtain a temperature change first curve based on the real-time temperature of the converter power module; the temperature calculation unit is configured to obtain a temperature change second curve based on the reference temperature of the converter power module; the temperature diagnosis unit is configured to compare the temperature change first curve with the temperature change second curve to diagnose whether the heat dissipation link of the converter power module is abnormal.

9. The heat dissipation link diagnosis system of the converter power module according to claim 8, wherein the temperature detection unit comprises a power module internal temperature detection unit and a radiator inlet temperature detection unit; wherein, the power module internal temperature detection unit is configured to obtain the real-time temperature of the converter power module; the radiator inlet temperature detection unit is configured to obtain the reference temperature of the converter power module.

10. The heat dissipation link diagnosis system of the converter power module according to claim 9, wherein the radiator inlet temperature detection unit comprises an air inlet temperature detection unit and / or a liquid inlet temperature detection unit; wherein, the air inlet temperature detection unit is configured to detect the air temperature at the air inlet of the air-cooled radiator; the liquid inlet temperature detection unit is configured to detect the cooling medium temperature at the liquid inlet of the liquid-cooled radiator.

11. A computer readable storage medium having stored thereon a computer program, wherein, The computer program is executed by a processor to implement the steps of the method of any one of claims 1 to 7.

12. A computer program product comprising computer programs / instructions, wherein, The computer program is executed by a processor to implement the steps of the method of any one of claims 1 to 7.

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