CN205945494U - Intelligent power modules and frequency converters containing them - Google Patents

Abstract

The utility model discloses an intelligent power module and a frequency converter containing the same. The intelligent power module includes: a drive control device, a structural component, at least one switch device, a heat dissipation system, a sensor, and a condition evaluation device for the heat dissipation system. The drive control The device is electrically coupled to the switching device and the cooling system status evaluation device; the sensor collects at least one parameter of the switching device and the cooling system; the cooling system status evaluation device receives the parameter, It is used to judge the condition of the cooling system and the cause of the failure of the cooling system. The method and device for evaluating the condition of the heat dissipation system of the power module of the utility model can evaluate the condition of the heat dissipation system of the power module, and at the same time preliminarily determine the location and cause of the fault.

Description

Intelligent power modules and frequency converters containing them

technical field

The present disclosure generally relates to the technical field of electronic circuits, and specifically relates to an intelligent power module and a frequency converter including the same.

Background technique

In high-power power electronic products, the power module composed of switching devices (including but not limited to insulated gate bipolar transistors, metal-oxide semiconductor field effect transistors, etc.) is the core part of the product. Performance and design specifications basically determine the main performance indicators of high-power power electronic products.

In the traditional high-power power electronic devices composed of inverters, frequency converters or converters and other equipment occupy a large proportion, and the core components of such power electronic devices are three-phase inverters composed of switching devices. . High-power inverters work in a high-voltage and high-current environment, which has high requirements for the reliability and availability of the converter system. How to design a power module that is easy to maintain, has high reliability, and has ultra-high availability, It is the most important subject in power electronics design.

In the current mainstream power module design scheme, only the temperature of a certain point around the switching device is judged for over-temperature. point, compare the sampled temperature value with a fixed value, when the sampled temperature value is higher than a certain fixed value, the power module stops working immediately and reports an over-temperature fault. However, there are many reasons for reporting an over-temperature fault, including over-power output, high ambient temperature, dust accumulation on the radiator, poor radiator fins or blockage of the coolant flow channel, poor thermal conductive silicone grease, interference or damage to the sampling protection circuit, resulting in an error. Protection, etc. It is difficult for analysts to judge the specific cause of the fault from the point of over-temperature fault. It is necessary to remove the power module from the machine for inspection, and multiple disassembly and assembly tests can find out the cause, which greatly reduces the maintenance efficiency of the module.

Therefore, a new power module is needed for evaluating the condition of the heat dissipation system of the power module.

The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in the art to a person of ordinary skill in the art.

Utility model content

The present disclosure provides an intelligent power module and a frequency converter containing it, capable of early warning of faults and preliminary judgment of fault locations.

Other features and advantages of the present disclosure will become apparent from the following detailed description, or in part, be learned by practice of the present disclosure.

According to one aspect of the present disclosure, an intelligent power module is provided, including: a drive control device, at least one switching device, a heat dissipation system, a sensor, and a condition evaluation device for a heat dissipation system,

The sensor collects at least one parameter of the power module;

The cooling system status evaluation device receives the parameters to determine the cooling system status and the cause of the cooling system failure;

The driving control device is electrically coupled to the switching device and the heat dissipation system condition evaluation device respectively, and controls the switching device.

In an exemplary embodiment of the present disclosure, the heat dissipation system condition assessment device includes: a signal conditioning circuit, an analog-to-digital conversion circuit, and a computing processing chip,

The signal conditioning circuit receives the signal collected by the sensor;

The analog-to-digital conversion circuit receives the signal output by the signal conditioning circuit;

The calculation processing chip receives the signal output by the analog-to-digital conversion circuit and the external communication signal.

In an exemplary embodiment of the present disclosure, the computing processing chip is a microprocessor chip or an integrated circuit chip.

In an exemplary embodiment of the present disclosure, the heat dissipation system includes an air-cooled heat dissipation system and/or a water-cooled heat dissipation system.

In an exemplary embodiment of the present disclosure, the air-cooled heat dissipation system includes a cooling assembly and a cooling fan; the water-cooled heat dissipation system includes a cooling assembly and a circulation pump.

In an exemplary embodiment of the present disclosure, the parameters include the voltage of the DC busbar, the output current of the intelligent power module, the ambient temperature of the intelligent power module, and the temperature of the cooling components of the heat dissipation system. One or more of an inlet temperature, an outlet temperature of a cooling component of the heat dissipation system, an internal temperature of the switching device, and a switching signal frequency of the switching device.

In an exemplary embodiment of the present disclosure, the heat dissipation system condition evaluation device is configured to calculate the thermal resistance between the node of the switching device and the environment according to the parameters, and compare the thermal resistance with the first The preset value is compared, and the condition of the heat dissipation system is judged according to the comparison result.

In an exemplary embodiment of the present disclosure, the heat dissipation system condition evaluation device is configured to determine that the condition of the heat dissipation system is good when the thermal resistance is less than the first preset value; When the value is greater than the first preset value, an early warning signal is issued.

In an exemplary embodiment of the present disclosure, the heat dissipation system condition evaluation device is configured to compare the thermal resistance with a second preset value, and when the thermal resistance exceeds the second preset value , to issue a fault shutdown signal.

In an exemplary embodiment of the present disclosure, the heat dissipation system condition evaluation device is used to calculate the internal junction temperature of the switching device, and when the internal junction temperature of the switching device exceeds a third preset value, an over-temperature An early warning signal, when the internal junction temperature of the switching device exceeds a fourth preset value, an over-temperature fault signal is sent.

In an exemplary embodiment of the present disclosure, the heat dissipation system condition evaluation device is configured to calculate the cooling fluid flow rate of the heat dissipation system, and judge the cause of the failure according to the change of the thermal resistance and the flow rate.

In an exemplary embodiment of the present disclosure, there are multiple switching devices, and a single-phase topology, a dual-phase topology or a three-phase topology is adopted.

In an exemplary embodiment of the present disclosure, the intelligent power module further includes:

A DC busbar, the DC busbar includes a positive DC busbar and a negative DC busbar, electrically coupled to the DC positive and negative terminals of the intelligent power module, respectively;

an AC busbar, the AC busbar is electrically coupled to the AC terminal of the intelligent power module;

A DC support capacitor, the DC support capacitor is electrically coupled to the DC positive and negative terminals of the intelligent power module.

In an exemplary embodiment of the present disclosure, the sensor includes one or more of the following: a voltage sensor electrically coupled to the DC positive and negative terminals of the intelligent power module, and connected in series to the AC busbar A current sensor for measuring the ambient temperature, a plurality of second temperature sensors for measuring the temperature of the plurality of switching devices, a third temperature sensor for measuring the inlet of the cooling component of the cooling system, and measuring the temperature of the cooling system Fourth temperature sensor at the outlet of the cooling assembly.

According to one aspect of the present disclosure, a frequency converter is provided, including: at least one intelligent power module with any structure described above.

The intelligent power module of the utility model can evaluate the condition of the cooling system of the power module and give an overall evaluation score. At the same time, it can also preliminarily judge the location and cause of the fault, including early warning of dust accumulation in the radiator and pipe blockage, early warning of abnormal cooling fan or circulating pump in the cooling system, early warning of other abnormalities in the radiator, such as falling off of cooling fins, damage to cooling pipes, etc. Severe shutdown due to dust accumulation and pipeline blockage, over-temperature warning and over-temperature fault protection for switching devices.

It is to be understood that both the foregoing general description and the following detailed description are exemplary only and are not restrictive of the present disclosure.

Description of drawings

The above and other objects, features and advantages of the present disclosure will become more apparent by describing in detail example embodiments thereof with reference to the accompanying drawings.

Fig. 1 shows a schematic diagram of fault judgment of a power module in the prior art.

Fig. 2 shows a schematic diagram of a topology and parameter sampling points of a power module according to an exemplary embodiment of the present disclosure.

Fig. 3 shows schematic diagrams of three topological structures of power modules.

FIG. 4 shows a schematic diagram of an air-cooled heat dissipation system according to an exemplary embodiment of the present disclosure.

FIG. 5 shows a schematic diagram of a water-cooled heat dissipation system according to an exemplary embodiment of the present disclosure.

Fig. 6 shows a schematic diagram of the design idea of the utility model.

FIG. 7 shows a block diagram of an apparatus for evaluating the condition of a heat dissipation system of a power module according to an exemplary embodiment of the present disclosure.

FIG. 8 shows a flow chart of a method for evaluating the condition of a heat dissipation system of a power module according to an exemplary embodiment of the present disclosure.

FIG. 9 illustrates a cooling system condition assessment score curve according to an example embodiment of the present disclosure.

FIG. 10 shows a relationship diagram of the internal junction temperature Tj of the switching device, the output power P of the power module, and the ambient temperature Ta according to an exemplary embodiment of the present disclosure.

detailed description

Example embodiments will now be described more fully with reference to the accompanying drawings. Example embodiments may, however, be embodied in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete and will fully convey the concept of example embodiments to those skilled in the art. The drawings are merely schematic illustrations of the present disclosure and are not necessarily drawn to scale. The same reference numerals in the drawings denote the same or similar parts, and thus repeated descriptions thereof will be omitted.

Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided in order to give a thorough understanding of embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure may be practiced without one or more of the specific details being omitted, or other methods, components, steps, etc. may be adopted. In other instances, well-known structures, methods, implementations, or operations are not shown or described in detail to avoid obscuring aspects of the present disclosure.

Some of the block diagrams shown in the drawings are functional entities and do not necessarily correspond to physically or logically separate entities. These functional entities may be implemented in software, or in one or more hardware modules or integrated circuits, or in different network and/or processor means and/or microcontroller means.

Fig. 2 shows a schematic diagram of a topology and parameter sampling points of a power module according to an exemplary embodiment of the present disclosure. As shown in FIG. 2, the power module 200 includes a switch device 201, a switch device cooling assembly 202 (including a water-cooled cooling assembly and/or an air-cooled cooling assembly), an AC bus bar 203, a DC bus bar 204, a DC support capacitor 205, A drive control device 206, various sensors and a cooling system condition evaluation device 207. The sensors include a current sensor 208 for measuring the output current parameters of the module, a voltage sensor 209 for measuring the voltage at both ends of the DC busbar, a temperature sensor 210 for measuring the internal temperature of the switching device, a temperature sensor 211 for measuring the temperature at the inlet of the cooling device for the switching device, and a measuring switch A temperature sensor 212 for the outlet temperature of the device cooling device, and a temperature sensor 213 for measuring the ambient temperature.

Fig. 3 shows schematic diagrams of three topological structures of power modules. As shown in Figure 3, power modules can be divided into single-phase modules, dual-phase modules, and three-phase modules according to the number of phases. Both dual-phase modules and three-phase modules are derived from single-phase modules, which are two or three Single-phase modules are connected in parallel and share the DC support capacitor and its related components.

As the power output module of the converter (inverter) system, the power module 200 will inevitably generate losses when the switching device 201 outputs power, and these losses will be directly converted into heat. If these heats are not taken away in time, it will directly cause If the internal temperature of the switching device 201 rises, if the switching device 201 works at high temperature for a long time, the working life of the switching device 201 will be greatly reduced. When the internal temperature of the switching device 201 is higher than a limit value, it will directly lead to its failure. The heat generated by the switching device 201 in the power module 200 is mainly taken away by the switching device cooling assembly 202, so that the switching device 201 is in a good working environment, and the operation stability and life of the switching device 201 are improved. At present, the switching device cooling assembly 202 is divided into an air-cooling cooling assembly and a water-cooling cooling assembly. As shown in Figure 4, the cooling fan 401 in the system and the air-cooled cooling assembly form an air-cooled heat dissipation system, the air-cooled cooling assembly includes thermal conductive silicone grease 402 and an air-cooled radiator 403, and the air-cooled radiator 403 has an air inlet 404 and the air outlet 405 , the switching device 201 is disposed on the thermal conductive silicone grease 402 of the air-cooled radiator 403 . As shown in Figure 5, the circulating water pump 501 and the water-cooled cooling assembly in the system form a water-cooled heat dissipation system. The water-cooled cooling assembly includes thermal conductive silicone grease 502 and a water-cooled plate 503. The water-cooled plate 503 has a water inlet 504 and a water outlet 505. The switching device 201 is set on the heat conduction silicone grease 502 of the water cooling plate 503 .

Due to the long-term operation of the air-cooled heat dissipation system or the operation in a relatively harsh environment (dusty, windy sand, etc.), dust accumulation in the air-cooled radiator 403 will reduce the flow of air volume, thereby reducing the heat dissipation capacity of the heat dissipation system. Due to water quality, electrical corrosion, etc., the water-cooled heat dissipation system will easily block the heat dissipation pipes after a long time, thereby reducing the heat dissipation capacity of the water-cooled heat dissipation system. Dust accumulation in the air-cooled radiator 403 or blockage of the heat dissipation pipe will seriously affect the heat dissipation of the switch device 201 , so that the switch device 201 will work in a relatively high temperature environment for a long time, greatly reducing the service life of the switch device 201 . Even when the output power P of the power module 200 is relatively large, the temperature of the switching device 201 is too high due to the reduction of the heat dissipation capacity of the heat dissipation system, so that over-temperature protection occurs, and the power module 200 can only be shut down for maintenance or load-reduced operation, which greatly The utilization rate of the power module 200 is reduced.

The utility model combines previous experience, based on the complexity of the failure causes of the heat dissipation system of the power module, and comprehensively considers the intelligent design requirements of the power module of the high-power inverter, and proposes a method and device for evaluating the condition of the heat dissipation system of the power module. The idea is shown in Figure 6. On the basis of collecting the temperature of each part of the power module 200, combined with the real-time parameters of the operation of the power module 200, such as the voltage and output current of the DC busbar, through calculation, analysis and comparison of various key parameters, a comprehensive score of the cooling system status is obtained . When the comprehensive score is lower than a predetermined value, the heat dissipation system condition assessment device 207 sends a sub-health warning message to the system, and in the warning state, the power module 200 needs to be properly de-loaded. When the comprehensive score is lower than a limit value, the heat dissipation system status evaluation device 207 sends an abnormal signal to the system, and at the same time, the power module 200 actively shuts down. When a characteristic parameter in each index is outside the limit standard, for example, when the internal junction temperature T _j of the switching device exceeds a predetermined value, the power module 200 will automatically shut down and report a corresponding fault signal. After the system receives the early warning from the power module 200, the maintenance personnel have enough time to prepare for its maintenance. When the power module 200 is shut down for protection, the problem of the cooling system can be determined or eliminated through the previous warning and other information, and the maintenance efficiency can be improved. .

FIG. 7 shows a block diagram of a device for evaluating the condition of the heat dissipation system of a power module according to an example embodiment of the present disclosure. In combination with FIGS. The sensor is used to collect the voltage of the DC busbar 204 of the power module 200, the output current of the power module 200, the ambient temperature T _a of the power module 200, the inlet temperature T _in of the cooling component of the power module 200, and the cooling temperature of the power module 200 The component outlet temperature T _out , the temperature T _ntc of a thermistor at a certain point inside the switching device 201 , and the like. After the collected signal passes through the signal conditioning circuit, the analog-to-digital conversion module transmits the collected signal to the processing module. The processing module 704 may use a Microcontroller Unit (Microcontroller Unit; MCU) or a specially designed integrated circuit (Application Specific Integrated Circuit; ASIC). The frequency of the switching signal of the power module is provided by the system where the power module 200 is located and transmitted to the processing module. The processing module can store a plurality of parameters, and some parameters can be adjusted according to the cooling components of the switching device used. The parameters that need to be adjusted can be adjusted through external communication. The adjustable parameters include the thermal resistance R _jn between the internal node of the power module switching device and the thermistor, the specific heat capacity C of the cooling fluid, the conduction correction coefficient λ, The comprehensive score warning value of the cooling system, the comprehensive score protection shutdown value of the cooling system and the over-temperature protection shutdown value. The cooling system status evaluation device 207 calculates the output power P of the power module in real time through the collected voltage and output current of the DC busbar; calculates the power loss P of the switching device in real time through the voltage, output current and switching signal frequency of the DC busbar _loss ; Calculate the junction temperature T _j of the switching device through the power loss P _loss of the switching device, the temperature T _ntc of the internal thermistor of the switching device and the thermal resistance R _jn ; according to the thermal resistance R between the internal node of the switching device and the thermistor _jn , power loss P _loss of the switching device, internal thermistor temperature T _ntc of the switching device, and ambient temperature T _a to calculate the thermal resistance R _ja between the node of the power module switching device and the environment; The cooling fluid flow Q is estimated from the deviation ΔT, the switching device loss power P _loss , the specific heat capacity C of the cooling fluid, and the conduction correction parameter λ. Judging module 706, for comparing the thermal resistance R _ja between the node of the switching device and the environment with the first preset value, when judging the condition of the heat dissipation system according to the comparison result; according to the thermal resistance between the node of the switching device and the environment The cause of the fault can be judged by the change of thermal resistance R _ja and cooling fluid flow Q. In an embodiment, the judging module 706 is further configured to compare the thermal resistance R _ja between the switch device node and the environment with a second preset value, and when the thermal resistance exceeds the second preset value, Send a fault shutdown signal.

FIG. 8 shows a flow chart of a method for evaluating the condition of a heat dissipation system of a power module according to an exemplary embodiment of the present disclosure.

As shown in FIG. 8 , the method for assessing the condition of the heat dissipation system of a power module is based on the structure of the above-mentioned power module 200, and includes steps S802-S812:

In step S802, the ambient temperature T _a where the power module 200 is located, the temperature T _ntc of the internal thermistor of the switching device, the output current of the power module, the switching frequency of the switching device, the voltage of the DC busbar, and the cooling components of the heat dissipation system are collected. The inlet temperature T _in of the heat dissipation system and the outlet temperature T _out of the cooling components of the heat dissipation system.

The heat dissipation system condition evaluation device 207 collects the ambient temperature T _a of the power module 200 through sensors, the internal thermistor temperature T _ntc of the switching device, the output current of the power module, the voltage of the DC busbar, and the inlet temperature of the cooling components of the heat dissipation system T _in and the outlet temperature T _out of the cooling components of the heat dissipation system.

In step S804, the power loss P _loss of the switching device is calculated according to the voltage of the DC bus, the output current of the power module and the switching signal frequency of the switching device.

The power loss P _loss of the switching device is calculated according to the collected DC bus voltage, the output current of the power module 200 and the switching signal frequency of the power module switching device 201 provided by the system where the power module 200 is located. There are many methods for calculating the power loss P _loss in the prior art, and the present invention is not limited to specific calculation methods.

In step S806, the switching device is calculated according to the ambient temperature T _a of the power module, the internal thermistor temperature T _ntc of the switching device, the power loss P _loss and the thermal resistance R _jn between the internal node of the switching device and the thermistor The thermal resistance R _ja between the junction and ambient.

According to the collected ambient temperature T _a of the power module, the temperature T _ntc of the internal thermistor of the switching device, the power loss P _loss and the thermal resistance R _jn between the internal node of the switching device and the thermistor, the junction of the switching device is calculated. The thermal resistance R _ja between the node and the environment, there are many specific calculation methods, for example, the following formula can be used to calculate the thermal resistance R _ja between the node of the switching device and the environment,

${\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}\mathrm{<span\; class="notranslate">\; a</span>}}<span\; class="notranslate">\; =</span>{\mathrm{<span\; class="notranslate">\; R</span>}}_{\mathrm{<span\; class="notranslate">\; j</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; +</span>\frac{{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; no</span>}\mathrm{<span\; class="notranslate">\; t</span>}\mathrm{<span\; class="notranslate">\; c</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; a</span>}}}{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}}}<span\; class="notranslate">\; .</span>$

In step S808, the cooling fluid flow rate Q is estimated according to the inlet temperature T _in of the cooling component of the cooling system, the outlet temperature T _out of the cooling component of the cooling system, the loss power P _loss , the specific heat capacity C of the cooling fluid, and the conduction correction parameter λ.

Calculate the cooling fluid flow Q according to the inlet temperature T _in of the cooling component of the cooling system, the outlet temperature T _out of the cooling component of the cooling system, the loss power P _loss , the specific heat capacity of the cooling fluid C, and the conduction correction parameter λ. The specific calculation method can be as follows There are many kinds, for example, the cooling fluid flow Q can be calculated by the following formula,

$\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}}}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; *</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; u</span>}\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; C</span>}}<span\; class="notranslate">\; .</span>$

In step S810, the thermal resistance R _ja between the junction of the switching device and the environment is compared with a first preset value, and the condition of the heat dissipation system is judged according to the comparison result.

Comparing the thermal resistance R _ja between the junction of the switching device and the environment with a first preset value, if it is less than the first preset value, the heat dissipation system is in good condition, and if it is greater than the first preset value, the heat dissipation If the system is abnormal, an early warning signal is issued. The first preset value may be that when the power module 200 is operating at full load, the ambient temperature T _a and the junction temperature T _j of the switching device are the thermal resistance between the junction of the switching device and the environment in an ideal state.

It is also possible to compare the thermal resistance R _ja between the junction of the switching device and the environment with a second preset value, and when the thermal resistance R _ja exceeds the second preset value, a fault shutdown signal is issued. The first preset value and the second preset value can be set and modified according to system conditions and specific needs of users.

In step S812, the cause of the fault is determined according to the thermal resistance R _ja between the junction of the switching device and the environment and the change of the flow rate Q of the cooling fluid.

After calculating the thermal resistance R _ja between the junction of the switching device and the environment and the flow rate Q of the cooling fluid, the location or cause of the fault can be preliminarily judged according to the changes of these two parameters.

In the above method, the evaluation index of the condition of the heat dissipation system is based on the thermal resistance R _ja between the node of the switching device of the power module and the environment. The heat dissipation system condition evaluation score curve is shown in Figure 9. Theoretically, the power module has a designed standard thermal resistance R _{ja_s} . When the actual thermal resistance R _ja is smaller than the standard thermal resistance R _{ja_s} , it may be because the radiator part of the heat dissipation system is normal. If the speed of the cooling fan increases or the flow rate of the circulating water pump increases, the actual thermal resistance R _ja will be smaller than the standard thermal resistance R _{ja_s} in this case, but no matter how small it is, the cooling system is considered to be in an ideal state, and it is judged as heat dissipation at this time. The system condition score D is 100. When the actual thermal resistance R _ja is greater than the standard thermal resistance R _{ja_s} , we believe that the performance of the heat dissipation system is degraded. As the actual thermal resistance R _ja value becomes larger and larger, the condition score D is getting lower and lower. When the actual thermal resistance R _ja reaches the maximum The condition score D is 0 at the value _Rjamax .

In an ideal state, that is, when the entire heat dissipation system is in a standard state, the relationship between the internal junction temperature T _j of the switching device and the thermal resistance R _ja is Where ξ is the power loss of the power module 200 under full load operation. In one embodiment, under full load operating conditions, when the ambient temperature is 50°C, the ideal internal junction temperature T _j of the switching device is 125°C, and the corresponding thermal resistance R _ja is the standard thermal resistance R _{ja_s} . When the internal junction temperature T _j of the switching device reaches 135° C., the corresponding thermal resistance R _ja is the standard thermal resistance R _{ja_w} , and the status score D of the power module 200 is 60. When the internal junction temperature _Tj of the switching device reaches 150°C, the status score D of the power module is 0. The status score D of the power module 200 is only related to the thermal resistance R _ja and has no relationship to the external ambient temperature. When evaluating and calculating the condition of the cooling system, the calculation is based on the thermal resistance R _ja . When the thermal resistance R _ja is less than or equal to the standard thermal resistance R _{ja_s} , the entire cooling system is in a relatively ideal working state; when the thermal resistance R _ja When it is greater than the standard thermal resistance R _{ja_s} , it is judged that the entire heat dissipation system is abnormal in varying degrees. At this time, the power module 200 will issue a sub-health warning to the system. The lower the status score D, the more serious the abnormality. When the thermal resistance R _ja increases to the value When R _{ja_w} , the heat dissipation system status score D is 60 points at this time, that is, when the internal junction temperature T _j of the switching device is greater than 135°C, it is judged that the heat dissipation system is abnormally serious, and an automatic shutdown is implemented. In one embodiment, the standard thermal resistance R _{ja_s} can be set as a first predetermined value, and an early warning will be given when the first predetermined value is reached, and the value R _{ja_w can} be set as a second predetermined value, and a shutdown will be performed when the second predetermined value is reached. Protection can also be set to other values as needed. The evaluation of the heat dissipation system status of the power module 200 is based on the comprehensive score of factors such as radiators, thermal grease, cooling medium flow, and cooling medium quality in the heat dissipation system. These factors ultimately affect the thermal resistance R _ja , so the power module condition The evaluation is based on the calculated thermal resistance R _ja to perform scoring. There are two types of factors that affect the thermal resistance R _ja between the junction of the switching device and the environment: the first factor is the flow path factor, the flow path of the air-cooled heat dissipation system is the passage of heat dissipation air, and the flow path of the water-cooled heat dissipation system The channel is the channel through which the coolant circulates. When the power module 200 runs for a long time, the flow channel of the air-cooled heat dissipation system will become narrow due to problems such as dust accumulation or foreign matter intrusion, or the air-cooled radiator 403 will Dust or aging causes the flow rate of air blown out from the air-cooled heat sink 403 to be reduced. These two situations will directly cause the flow rate of air flowing through the air-cooled heat sink 403 to decrease, thereby causing the gap between the switching device node and the environment. The thermal resistance R _ja becomes larger. The water-cooled radiator, such as the water-cooled plate 503 , has electrochemical corrosion phenomenon. After running for a long time, the electrochemical influence accumulates, resulting in the internal flow channel of the water-cooled plate 503 becoming smaller. The fine particles after electrochemical corrosion are doped in the cooling liquid, the quality of the cooling liquid used by the user is not up to standard, or the abnormality of the circulating water pump of the water cooling system causes the flow rate of the water cooling plate 503 to decrease. These three situations will cause the switching device to be damaged. The thermal resistance R _ja between the junction and the environment becomes larger. The second factor is that the heat sink or thermal grease is abnormal. Due to the manufacturing process of the air-cooled radiator 403, the cooling fins may be loose or fall off, and the water-cooled radiator may have problems such as poor welding, which will make the radiator The heat dissipation capability of the heat sink decreases, thereby affecting the thermal resistance R _ja . Both the air-cooled heat dissipation system and the water-cooled heat dissipation system use thermally conductive silicone grease. If the coating of thermally conductive silicone grease is too thick or too thin, the conduction effect will be poor, thereby affecting the thermal resistance R _ja . At the same time, the heat-conducting silicone grease will dry out over time, and due to the effect of gravity, the heat-conducting silicone grease will slowly flow toward the ground plane, and this flow will make the heat-conducting silicone grease distributed at the bottom of the switching device 201 Uneven, these situations will lead to larger thermal resistance R _ja .

In the process of judging the abnormal fault of the heat dissipation system, the two parameters of the thermal resistance R _ja and the estimated cooling fluid flow Q are used as the judgment basis.

According to the law of energy conservation, once the heat dissipation system reaches thermal equilibrium, the temperature of each point inside the power module 200 reaches the equilibrium point, and the temperature of each point remains unchanged. At this time, the power loss P _loss of the switching device 201 should be equal to the dissipation power of the heat dissipation system. The power is equal, the dissipated power of the heat dissipation system is the heat taken away by the cooling fluid per unit time, and the flow rate Q of the cooling fluid at this time can be estimated when the temperature rise of the cooling fluid at the inlet and outlet of the radiator is known. In one embodiment , can be calculated by the following formula:

$\mathrm{<span\; class="notranslate">\; Q</span>}<span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; P</span>}}_{\mathrm{<span\; class="notranslate">\; l</span>}\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}\mathrm{<span\; class="notranslate">\; the\; s</span>}}}{\mathrm{<span\; class="notranslate">\; \&lambda;</span>}<span\; class="notranslate">\; *</span><span\; class="notranslate">\; (</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; o</span>}\mathrm{<span\; class="notranslate">\; u</span>}\mathrm{<span\; class="notranslate">\; t</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; T</span>}}_{\mathrm{<span\; class="notranslate">\; i</span>}\mathrm{<span\; class="notranslate">\; no</span>}}<span\; class="notranslate">\; )</span><span\; class="notranslate">\; *</span>\mathrm{<span\; class="notranslate">\; C</span>}}$

If it is detected that the thermal resistance R _ja becomes larger and the cooling fluid flow rate Q becomes smaller, there may be two reasons in this case: the first is the internal dust accumulation or blockage of the radiator, which will reduce the heat dissipation effect of the radiator. As a result, the thermal resistance R _ja becomes larger, and at the same time, due to dust accumulation or blockage, the flow resistance inside the radiator will become larger, which will cause the flow Q of the cooling fluid to become smaller; the second is the heat dissipation of the cooling system A decrease in the fan speed or a decrease in the speed of the circulation pump results in a decrease in the flow Q of the cooling fluid, which also results in an increase in the thermal resistance R _ja . When either of these two situations occurs, the power module 200 will send a cooling system abnormal warning to the system. The system can judge whether it is a radiator according to whether multiple modules report a cooling system abnormal warning or a single module reports a cooling system abnormal warning. The problem of dust accumulation or blockage is also the problem of cooling fan or circulation pump. If the system receives multiple modules to report abnormal cooling system warnings, it means that there is a common problem among multiple power modules in the system. In this case, there should be a problem with the common parts of the power module cooling, and it can be determined that it is the cooling fan or The circulation pump is abnormal; if the system receives a cooling system abnormality warning reported by a single power module, it means that the power module has a personality problem, and it can be determined that the radiator of the power module has accumulated dust or is abnormally blocked.

If it is detected that the thermal resistance R _ja becomes larger and the cooling fluid flow Q is basically unchanged, it means that the fluid flow in the heat dissipation system is normal, and the possible situation is that the radiator itself is abnormal, and this abnormality can also be divided into Two types: Abnormal thermal conductive silicone grease or abnormal radiator. The abnormal radiator structure is abnormal, which may be caused by loose cooling fins or abnormal flow channels of the water-cooled radiator. These two abnormalities cannot be distinguished in detail, so these two abnormalities are classified into one category.

If it is detected that the thermal resistance _Rja remains unchanged and the flow rate Q of the cooling fluid increases significantly, it should also be judged as an abnormality of the thermal conductive silicone grease or the abnormality of the radiator, because the standard value of _Rja is based on knowing the value of the flow rate Q of the cooling fluid Based on the calculation, if the cooling fluid flow rate Q becomes larger, the theoretical thermal resistance R _ja becomes smaller, and at this time the thermal resistance R _ja is basically unchanged from the standard value, and in fact the thermal resistance R _ja is already greater than the actual calculated theoretical value , so the judgment result is consistent with the situation that the thermal resistance R _ja becomes larger while the flow rate Q of the cooling fluid remains basically unchanged.

The method for assessing the condition of the heat dissipation system of the power module in this embodiment can evaluate the condition of the heat dissipation system of the power module and give an overall assessment score. At the same time, it can also preliminarily judge the location and cause of the fault, including early warning of dust accumulation in the radiator and pipe blockage, early warning of abnormal cooling fan or circulating pump in the cooling system, early warning of other abnormalities in the radiator, such as falling off of cooling fins, damage to cooling pipes, etc. Severe downtime caused by dust accumulation and pipe blockage.

The power module 200 with the cooling system status evaluation device 207 not only transmits the cooling system status score D to the system, but also has functions such as over-temperature warning and over-temperature protection, and transmits these information to the system through a specified communication protocol.

The over-temperature early warning and over-temperature protection of the utility model take the internal junction temperature T _j of the switching device as a reference basis. In one embodiment, the calculation formula of the internal junction temperature T _j of the switching device is T _j = P _loss * R _ja + T _a , the internal junction temperature T _j of the switching device is not only related to the thermal resistance R _ja , but also related to the power loss P _loss of the power module 200 at this time and the ambient temperature T _a . The switching loss P _loss of the power module 200 is approximately proportional to the output power P. Under the ideal condition of R _ja , when the output power P of the power module 200 exceeds the rated power, the loss of the switching device 201 will also increase, resulting in the ambient temperature T When _a is relatively high, the internal junction temperature T _j of the switching device will exceed 125°C, and an over-temperature warning needs to be issued at this time. When the ambient temperature T _a is relatively low, the appropriate overpower of the power module 200 will not issue an over-temperature warning. Under the ideal condition of R _ja , the internal junction temperature T _j of the switching device is related to the output power P of the power module and the ambient temperature T The relationship diagram of _a is shown in Figure 10. During the actual operation of the power module 200, there may be a relatively large thermal resistance _Rja , but due to the relatively low ambient temperature or the relatively low temperature of the circulating fluid, the internal junction temperature _Tj of the switching device is not very high, even higher than the ideal junction temperature In this case, the power module 200 can still operate normally, but because the thermal resistance R _ja is relatively large, it has already indicated that there is a problem in the heat dissipation system, so the power module needs to send an early warning to the system. In one embodiment, when it is detected and calculated that the internal junction temperature T _j of the switching device exceeds the over-temperature warning value, an over-temperature warning should be issued to remind the system or maintenance personnel to maintain the power module 200. At this time, the power module 200 can still be normal. running, there will be no automatic shutdown protection. When the internal junction temperature T _j of the switching device exceeds the over-temperature protection value, the power module 200 will send an over-temperature fault signal to the system, and at the same time automatically shut down itself.

Adopting the method of the utility model allows maintenance personnel to have sufficient maintenance preparation time, and at the same time greatly reduces downtime and increases operating efficiency. After receiving the early warning signal, the maintenance personnel can determine which specific link in the power module cooling system is abnormal by reading the cooling system operating parameters stored in the storage device when the early warning signal is sent out, so as to adopt different maintenance measures.

Regarding the device in the above embodiment, the specific manner in which each module executes operations has been described in detail in the embodiment of the method, and will not be described in detail here.

Exemplary embodiments of the present disclosure have been specifically shown and described above. It should be understood that the disclosure is not limited to the detailed structures, arrangements or methods of implementation described herein; on the contrary, the disclosure is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.

Claims (15)

1. An intelligent power module, characterized in that it comprises: a drive control device, at least one switching device, a heat dissipation system, a sensor, and a condition evaluation device for a heat dissipation system, The sensor collects at least one parameter of the power module; The cooling system status evaluation device receives the parameters to determine the cooling system status and the cause of the cooling system failure; The driving control device is electrically coupled to the switching device and the heat dissipation system condition evaluation device respectively, and controls the switching device. 2. The intelligent power module according to claim 1, wherein the heat dissipation system condition evaluation device comprises: a signal conditioning circuit, an analog-to-digital conversion circuit, and a calculation processing chip, The signal conditioning circuit receives the signal collected by the sensor; The analog-to-digital conversion circuit receives the signal output by the signal conditioning circuit; The calculation processing chip receives the signal output by the analog-to-digital conversion circuit and the external communication signal. 3. The intelligent power module according to claim 2, wherein the computing processing chip is a microprocessor chip or an integrated circuit chip. 4. The intelligent power module according to claim 1, wherein the heat dissipation system comprises an air-cooled heat dissipation system and/or a water-cooled heat dissipation system. 5. The intelligent power module according to claim 4, wherein the air-cooled heat dissipation system includes a cooling assembly and a cooling fan; the water-cooled heat dissipation system includes a cooling assembly and a circulation pump. 6. The intelligent power module according to claim 1, wherein the parameters include the voltage of the DC busbar, the output current of the intelligent power module, the ambient temperature of the intelligent power module, the heat dissipation One or more of the inlet temperature of the cooling component of the system, the outlet temperature of the cooling component of the heat dissipation system, the internal temperature of the switching device, and the switching signal frequency of the switching device. 7. The intelligent power module according to claim 1, wherein the heat dissipation system condition evaluation device is used to calculate the thermal resistance between the node of the switching device and the environment according to the parameters, and the The thermal resistance is compared with the first preset value, and the condition of the heat dissipation system is judged according to the comparison result. 8. The intelligent power module according to claim 7, wherein the heat dissipation system status evaluation device is configured to determine that the heat dissipation system is in good condition when the thermal resistance is smaller than the first preset value; When the thermal resistance is greater than the first preset value, an early warning signal is issued. 9. The intelligent power module according to claim 7, wherein the heat dissipation system evaluation device is configured to compare the thermal resistance with a second preset value, and when the thermal resistance exceeds the first When the second preset value is reached, a fault shutdown signal is issued. 10. The intelligent power module according to claim 1, wherein the heat dissipation system condition evaluation device is configured to calculate the internal junction temperature of the switching device, when the internal junction temperature of the switching device exceeds a third preset value , an over-temperature warning signal is issued, and when the internal junction temperature of the switching device exceeds a fourth preset value, an over-temperature fault signal is issued. 11. The intelligent power module according to claim 7, wherein the heat dissipation system condition evaluation device is configured to calculate the cooling fluid flow rate of the heat dissipation system, and judge the fault according to the change of the thermal resistance and the flow rate reason. 12 . The intelligent power module according to claim 1 , wherein there are multiple switching devices, and a single-phase topological structure, a two-phase topological structure or a three-phase topological structure is adopted. 13. The intelligent power module according to claim 1, further comprising: A DC busbar, the DC busbar includes a positive DC busbar and a negative DC busbar, electrically coupled to the DC positive and negative terminals of the intelligent power module, respectively; an AC busbar, the AC busbar is electrically coupled to the AC terminal of the intelligent power module; A DC support capacitor, the DC support capacitor is electrically coupled to the DC positive and negative terminals of the intelligent power module. 14. The intelligent power module according to claim 13, wherein the sensor comprises one or more of the following: a voltage sensor electrically coupled to the DC positive and negative terminals of the intelligent power module, connected in series to the The current sensor on the AC busbar, the first temperature sensor for measuring the ambient temperature, the multiple second temperature sensors for measuring the temperature of the multiple switching devices, the third temperature sensor for measuring the inlet of the cooling component of the heat dissipation system, and the measurement The fourth temperature sensor at the outlet of the cooling component of the heat dissipation system. 15. A frequency converter, characterized by comprising: at least one intelligent power module with a structure according to any one of claims 1-14.