POWER CONVERTER DEVICE, ESTIMATING PROGRAM AND ESTIMATING METHOD

Abstract

A current transformer device according to one aspect of the present disclosure comprises a base plate, a support on the base plate, a heat-generating element and a temperature sensor located on the support, and a control unit, and is connected to a load. The control unit includes a heat quantity calculation unit, which calculates a heat quantity of the heat-generating element based on information about the load; a refrigerant temperature calculation unit, which calculates a temperature of the refrigerant based on a flow rate of a refrigerant cooling the heat-generating element; and a thermal resistance calculation unit, which calculates a resistance value of the thermal resistance based on the flow rate and temperature of the refrigerant in a thermal model that represents the heat transferred between two different points under the heat-generating element, the base plate, the support, and the refrigerant as thermal resistance.a base plate temperature calculation unit, which calculates a temperature of the base plate based on the amount of heat and the thermal resistance, and a unit for calculating the temperature of the heat generating element, which calculates a temperature of the heat generating element based on the amount of heat and the temperature of the base plate.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a power conversion device, an estimation program, and an estimation method. GENERAL STATE OF THE ART

[0002] In a semiconductor switching element forming an inverter, if the temperature at a junction of the semiconductor element exceeds a specified value, damage may occur. Therefore, it is necessary to monitor the temperature of the semiconductor elements and adjust the output power to prevent damage to the semiconductor elements. Since placing a temperature sensor near the junction of the semiconductor elements increases costs, a temperature sensor is often placed at a position away from the semiconductor elements on the circuit board on which the semiconductor elements are mounted. In this case, there is a risk of lacking an adequate overheat protection function due to the poor response of the sensor.

[0003] Therefore, there is a method in which the temperature of a semiconductor element is estimated and the current flowing through the semiconductor element is restricted, causing the estimated temperature to exceed a permissible temperature and cause damage, thereby achieving overheat protection for the semiconductor elements and the power converter (see, for example, Patent Document 1). Patent Document 1 discloses a semiconductor chip temperature estimation device composed of a loss estimation unit for a semiconductor chip, a temperature estimation unit for a cooling element that cools the semiconductor chip, and a temperature rise estimation unit of the semiconductor chip.In this method, based on the loss calculated by the loss estimation unit, an estimated value of the refrigerant temperature, which is a base temperature, and a rise proportion of the semiconductor element temperature from this refrigerant temperature are calculated, and by summing the two, the semiconductor element temperature is estimated.

[0004] Generally, overheat protection control is effective when the estimated value of the semiconductor element temperature exceeds a preset threshold. This threshold is set at a value where a safety margin is deducted from the allowable temperature for the semiconductor element, with the margin depending on the estimation accuracy of the semiconductor element temperature. If the estimation accuracy is low, the problem arises that even if there is still a margin up to the allowable temperature, the overheat protection is triggered, making it impossible to achieve the desired output power. The higher the estimation accuracy, the smaller the margin can be set, thus enabling maximum output power from the converter.

[0005] Also known in the art is a technique in which, based on a temperature detected by a temperature sensor installed near a heat generating element (e.g., a switching element) of a power conversion device, the temperature of other elements not equipped with a temperature sensor is estimated (see, for example, Patent Document 2). PRIOR ART DOCUMENTS PATENT DOCUMENTS Patent Document 1: WO No. 2014 / 091852 Patent Document 2: JP 2011-97812 A SUMMARY OF THE INVENTION OBJECT OF THE INVENTION

[0006] The state of the art described above is problematic in that it may happen that the temperature of the elements of the current transformer device or the temperature and the amount of heat cannot be estimated with accuracy.

[0007] For example, in the technique of Patent Document 1, the temperature of the refrigerant and the influence of the flow velocity are not considered when calculating the rise rate of the semiconductor chip temperature, so the temperature estimation accuracy decreases depending on the usage situation.

[0008] The present disclosure provides a technique for estimating the temperature of the elements of the power conversion device or the temperature and the amount of heat with high accuracy. MEANS FOR SOLVING THE TASK

[0009] In order to solve the above-mentioned problems, a power conversion device according to one aspect of the present disclosure is a power conversion device comprising a base plate, a support provided on the base plate, a heat generating element and a temperature sensor provided on the support, and a control unit, and is connected to a load, and is characterized in that the control unit comprises a heat quantity calculation unit that calculates a heat quantity of the heat generating element based on information about the load, a refrigerant temperature calculation unit that calculates a temperature of the refrigerant based on a flow rate of a refrigerant cooling the heat generating element, a thermal resistance calculation unit that calculates the temperature of the refrigerant based on the flow rate and the temperature of the refrigerant in a thermal model that calculates the heat generated between two different points under the heat generating element, the base plate,expresses the heat transferred between the carrier and the refrigerant as thermal resistance, calculates a resistance value of the thermal resistance, and includes a base plate temperature calculation unit that calculates a temperature of the base plate based on the heat quantity and the thermal resistance, and a heat generating element temperature calculation unit that calculates a temperature of the heat generating element based on the heat quantity and the temperature of the base plate. EFFECT OF THE INVENTION

[0010] According to the present disclosure, the temperature of the elements of the power conversion device or the temperature and the amount of heat can be estimated with high accuracy. BRIEF DESCRIPTION OF THE CHARACTERS Fig. 1 is a view showing an example of the configuration of an estimation system according to a first embodiment. Fig. 2 is a view showing an example of the configuration of an estimation apparatus according to the first embodiment. Fig. 3 is an explanatory view of a model. Fig. 4 is a view showing a model of a first embodiment. Fig. 5 is a flowchart showing a processing flow of the estimation apparatus according to the first embodiment. Fig. 6 is an example arrangement of object positions. Fig. Figure 7 is an explanatory view of hotspots. Fig. 8 is a view showing a model of a second embodiment. Fig. 9 is a view showing a model of a third embodiment. Fig. 10 is a view showing a model of a fourth embodiment. Fig. 11 is a view showing a model of a fifth embodiment. Fig. 12 is a view showing an example of the configuration of an estimation system of a sixth embodiment. Fig. 13 is a view showing an example of the hardware configuration of the estimation apparatus according to the first embodiment. Fig. 14 is a view of an example of a thermal model according to a second embodiment. Fig. 15 is a view of an example of the thermal model according to the second embodiment. Fig. 16 is a view showing an example of the configuration of a power conversion device according to the second embodiment. Fig. 17 is a view showing an example of the configuration of a control device according to the second embodiment. Fig. 18 is a view showing an example of the configuration of a temperature estimation unit according to the second embodiment. Fig. 19 is a flowchart showing a processing flow of the power conversion device according to the second embodiment. Fig. 20 is a view showing an example of the configuration of the temperature estimation unit according to a third embodiment. Fig. 21 is an explanatory view of a winding water channel. Fig. 22 is an explanatory view of a straight water channel. Fig. 23 is a flowchart showing a processing flow of the power conversion device according to the third embodiment. EMBODIMENTS OF THE INVENTION

[0011] Hereinafter, ways of implementing a power conversion device, an estimation program, and an estimation method of the present disclosure (hereinafter referred to as "embodiments") will be described in detail with reference to the figures. However, the present disclosure is not limited by these embodiments. [First embodiment]

[0012] Fig. 1 is a view showing an example of the configuration of an estimation system according to a first embodiment. As shown in Fig. As shown in Figure 1, the estimation system 1 includes a converter device 10 and an estimation device 20. The converter device 10 is an example of a current transformer device.

[0013] The inverter device 10 converts direct current supplied from an external power source such as a battery or the like into alternating current and thus drives a load such as a motor or the like.

[0014] The converter device 10 includes heat-generating elements such as switching elements and freewheeling diodes (FWDs). The switching elements are, for example, IGBTs (insulated gate bipolar transistors). The switching elements can also be MOSFETs (metal oxide semiconductor field-effect transistors). The heat-generating elements also include busbars, capacitors, and inductors.

[0015] As in Fig. As shown in Figure 1, the inverter device 10 is divided into three parts: U-phase 11a, V-phase 11b, and W-phase 11c. Although not shown, the U-phase 11a, V-phase 11b, and W-phase 11c form a three-phase bridge circuit by being connected in parallel. Each phase is connected to a load (not shown). The load is, for example, a three-phase motor, and the U-phase 11a, V-phase 11b, and W-phase 11c are connected to the respective coils of the U-, V-, and W-phases. Here, a representative example of three-phase motor driving is given, but the inverter device 10 may be two-, four-, or more-phase.

[0016] In addition to the FWD and IGBT, a temperature sensor is provided on each phase. The temperature sensor is a thermistor, for example.

[0017] For example, an FWD 111a, an FWD 112a, an IGBT 113a, an IGBT 114a and a temperature sensor 121a are provided on the U-phase 11a.

[0018] For example, an FWD 111b, an FWD 112b, an IGBT 113b, an IGBT 114b and a temperature sensor 121b are provided on the V-phase 11b.

[0019] For example, an FWD 111c, an FWD 112c, an IGBT 113c, an IGBT 114c and a temperature sensor 121c are provided on the W phase 11c.

[0020] The arrangement of the temperature sensors is not based on the Fig. 1. Only a single temperature sensor may be provided for the converter device 10. For example, multiple temperature sensors may also be provided for the individual phases of the converter device 10.

[0021] The temperature sensor may be provided at a location adjacent to a heat generating element of the inverter device 10 or at a location not adjacent to a heat generating element. In the example of Fig. 1, temperature sensor 121a, temperature sensor 121b, and temperature sensor 121c are not adjacent to a heat-generating element. Preferably, the individual temperature sensors are arranged at a position on the substrate in the vicinity of a heat-generating element and in the vicinity of a hot spot, etc.

[0022] The estimation device 20 is a device for estimating the temperature or the heat quantity with respect to the inverter device 10. The estimation device 20 may be a microcomputer provided on the inverter device 10 or a computer separate from the inverter device 10.

[0023] The estimator 20 estimates the temperature or heat quantity of a position relative to the inverter device 10 based on the temperature detected by a temperature detection unit. Therefore, the estimator 20 can also estimate the temperature of a position whose temperature is not detected by a temperature sensor.

[0024] In particular, the estimation device 20 can estimate the temperature of heat generating elements such as switching elements and freewheeling diodes.

[0025] In an inverter device, it may happen that a temperature sensor is not provided in sufficient proximity to a heat-generating element. Furthermore, due to structural limitations, it may not be possible to install a temperature sensor in sufficient proximity to a heat-generating element.

[0026] Even in these cases, according to the estimation device 20 of the first embodiment, it is possible to estimate the temperature of the heat generating element.

[0027] Heat-generating elements such as switching elements and freewheeling diodes can be damaged by overheating. According to the first embodiment, by appropriately controlling heat dissipation, cooling, etc., of the heat-generating element based on the estimation result of the heat-generating element temperature, the heat-generating element and the inverter device can be protected.

[0028] The configuration of the estimator 20 is determined by Fig. 2 described. Fig. 2 is a view showing an example of the configuration of the estimation apparatus according to the first embodiment.

[0029] As in Fig. 2, the estimation device 20 comprises an input and output unit 21, a storage unit 22 and a control unit 23.

[0030] The input / output unit 21 is an interface for data input and output. The input / output unit 21 accepts inputs such as the temperature measured by the temperature sensors. Furthermore, the input / output unit 21 outputs the estimated temperature or heat quantity results to other devices, for example.

[0031] The input / output unit 21 can accept data input via input devices such as a keyboard, a mouse, and the like. The input / output unit 21 can also output data to an output device such as a display or the like.

[0032] The storage unit 22 and the control unit 23 are implemented, for example, by a computer having a CPU (central processing unit), ROM (read-only memory), RAM (random access memory), flash memory, input and output ports, and the like, or by various circuits.

[0033] Model information 221 can be stored in the storage unit 22. The control unit 23, for example, reads and executes a program stored in the storage unit 22, thus fulfilling the function of a calculation unit 231 and a compensation unit 232.

[0034] The model information 221 is information such as parameters for creating a model. The model of the first embodiment is a model that expresses a thermal resistance between target positions, including a thermal resistance between the position of a heat-generating element and the position of a temperature sensor on the inverter device 10, or a thermal resistance and mass flow rate of a heat dissipation portion. The heat dissipation portion is, for example, a water channel or fins.

[0035] Fig. 3 is an explanatory view of a model. As in Fig. As shown in Figure 3, the model is a model that simulates an electrical circuit. The model of the first embodiment is also referred to as a thermal model. Currents, voltages, and resistances in the electrical circuit correspond to heat quantities, temperatures, and thermal resistances in the thermal model.

[0036] In the example from Fig. 3, the model includes a variable temperature node 301, a thermal resistor 302, a thermal resistor 303, a variable temperature node 304, a thermal resistor 305, a variable temperature node 306, a mass flow dependent thermal resistor 307, a reference temperature node 308, a mass flow dependent thermal resistor 309, and a mass flow dependent variable temperature node 310.

[0037] The temperature of the variable-temperature nodes and the mass flow-dependent variable-temperature node are variables that change based on calculations. The temperature of the reference temperature node is a variable with a fixed value or a constant.

[0038] The resistance value of the thermal resistor is a variable with a fixed value or a constant. The resistance value of the mass flow-dependent thermal resistor changes with the mass flow rate of the heat dissipation section. The temperature of the mass flow-dependent variable-temperature node changes not only during the calculation but also with the mass flow rate of the heat dissipation section. The resistance value of the mass flow-dependent thermal resistor also changes with the temperature of the refrigerant (cooling water).

[0039] For example, the mass flow rate of the heat dissipation section is the mass flow rate of water flowing into the water channel. As the water mass flow rate increases, the resistance value decreases, while the heat dissipation performance increases.

[0040] In water convection, there are two types: forced convection and natural convection. The amount of heat transferred by forced convection is the product of the volume flow rate and the temperature. Therefore, this can also be viewed as a concept that the thermal resistance caused by forced convection and the thermal resistance caused by natural convection are different. However, the first version does not distinguish between the two and simply refers to "mass flow-dependent thermal resistance."

[0041] The temperature detected by the temperature sensor is set at the reference temperature node 308. A heat quantity Qigbt of the heat-generating element is input into the model.

[0042] The calculation unit 231 calculates the respective temperatures of the target positions based on the heat quantity of the heat generating element or the heat quantity of the heat generating element and the mass flow rate of the heat dissipating portion using the model expressing the thermal resistance between target positions including a thermal resistance between the position of a heat generating element and the position of a temperature sensor on the inverter device 10, or the model expressing the thermal resistance and the mass flow rate of a heat dissipating portion.

[0043] The calculation unit 231 calculates a temperature Tigbt of the variable-temperature node 301 based on the heat quantity Qigbt. Furthermore, the calculation unit 231 calculates the temperature Tbase based on the temperature Tigbt and a resistance value Rigbt-base of the thermal resistor 302.

[0044] The variable-temperature node 304 corresponds to the position of the temperature sensor. The temperature Tthermistor can therefore be referred to as the estimated value of the temperature detected by the temperature sensor. Thermal resistance 303 and thermal resistance 305 correspond to the thermal resistance of locations in the vicinity of the temperature sensor.

[0045] The calculation unit 231 calculates the temperature Tthermistor of the variable temperature node 304 based on the temperature Tigbt and the temperature Tbase.

[0046] In addition, the calculation unit 231 calculates a temperature Twater_out of the mass flow-dependent node 310 with variable temperature based on the resistance value Rbase-water of the mass flow-dependent thermal resistor 307, the temperature Twater_in of the reference temperature node 308, the resistance value of the mass flow-dependent thermal resistor 309 and the mass flow of the mass flow-dependent node 310 with variable temperature.

[0047] For example, the reference temperature node 308 and the mass flow dependent variable temperature node 310 correspond to endpoint positions of the heat dissipation section.

[0048] In this way, the calculation unit 231 calculates the respective temperature of the target positions from the model based on the heat amount of the heat generating element and the reference temperature set for at least one of the target positions.

[0049] In addition, the calculation unit 231 calculates the respective temperatures of the target positions based on the model expressing the thermal resistance including the thermal resistance between two positions selected from target positions including the position of the heat generating element, that is, the switching element or the flyback diode, a position on the base plate or the substrate that is not a hot spot formed by heat generated by respectively dissipating the heat generated by the heat generating element to the heat dissipation portion and the cooling water and is not adjacent to the heat generating element, an end point position of the heat dissipation portion provided on the inverter device 10, and the position of a temperature sensor.

[0050] The compensation unit 232 compensates based on the difference between the temperature calculated by the calculation unit 231 and the position of the temperature sensor (for example, Tthermistor from Fig. 3) and the temperature detected by the temperature sensor, the heat quantity of the target positions. Then, the calculation unit 231 further calculates the respective temperature of the target positions based on the temperature calculated with the heat quantity compensated by the compensation unit 232.

[0051] By feeding the calculated temperature back into the model in this way, the estimator 20 can increase the estimation accuracy. An embodiment of the feedback method is described below. (First embodiment)

[0052] Fig. 4 is a view showing a model of a first embodiment. As shown in Fig. As shown in Figure 4, a compensation node 311 was added to the model in the first embodiment. A detection temperature 401 is input to the compensation node 311. The detection temperature 401 is the temperature detected by the temperature sensor provided on the converter device 10.

[0053] In the first embodiment, the reference temperature node 308 was Fig. 3 is replaced by a mass flow-dependent variable-temperature node 308a. The more variable-temperature nodes included in the model, the more variables there are, which is why the computation speed tends to decrease but the estimation accuracy increases. The more reference temperature nodes or compensation nodes included in the model, the higher the estimation accuracy tends to be. The minimum number for the compensation node and the reference temperature node is one each.

[0054] In the circuit diagrams with the nodes from Fig. 4 etc., the processing operations have been schematized for descriptive purposes, and in practice it is not necessary to create circuit diagrams such as those shown.

[0055] The compensation unit 232 first calculates ΔT, which is the difference between Tthermistor and Tthermistor_sensor (detection temperature 401). Then, the compensation unit 232 performs PID (proportional integral derivative) control on ΔT. If multiple heat-generating elements are present, at least one of ΔQi, ΔQj, and ΔQk is obtained by multiplying the loss ratios of the heat-generating elements, the thermal resistance ratios from the positions of the heat-generating elements to the temperature sensor, or the ratios of the temperature at the positions of the heat-generating elements and the reference temperature. Compensation is also possible using P control alone, but for applications requiring sensitive response, I and D control are also required.

[0056] The following is a calculation example for the case where the compensation unit 232 multiplies the ratios. For example, Kpid_gain is ΔQk, while the part multiplied by Kpid_gain corresponds to the ratio. Preferably, uniform compensation can be achieved by using the heat quantity ratio of the second example. • Example of thermal resistance ratio Kpid_gain×(Rdiode_thermistor) / (Rigbt_thermistor+Rdiode_thermistor) • Example of the loss ratio of the heat quantity element Kpid_gain×Qibt_thermistor / (Qigbt_thermistor+Qdiode_thermistor) • Example of the relationship between temperature and reference temperature Kpid_gain×(Tigbt−Tthermistor) / ((Tigbt−Tthermistor)+(Tigbt−Tthermistor))

[0057] Where Rdiode_thermistor and Rdiode_thermistor are the respective thermal resistances between the heat-generating elements (IGBT and FWD) and the temperature sensor. Qdiode is the heat quantity of the FWD. Tigbt and Tdiode are the respective temperatures at the positions of the heat-generating elements (IGBT and FWD), and Twater is the reference temperature (e.g., the inlet water temperature at the heat dissipation section).

[0058] The compensation unit 232 compensates at least one of the heat quantity at the position of the heat generating element, the heat quantity at the end point position of the heat dissipation section, and the heat quantity at the location not adjacent to a heat generating element. Specifically, the compensation unit 232 adds ΔQi, ΔQj, or ΔQk ​​to the heat quantity at the Fig. 4 shown position.

[0059] For example, the compensation unit 232 adds ΔQi to the amount of heat at the variable-temperature node 306, which corresponds to the temperature of the support. The position of the variable-temperature node 306 corresponds to the support.

[0060] For example, the compensation unit 232 adds ΔQj to the heat quantity at the mass flow-dependent variable-temperature node 308a, which corresponds to the cooling water temperature. The position of the mass flow-dependent variable-temperature node 308a is the end point of the heat dissipation section. In the first embodiment, for example, the end point of the heat dissipation section is the inlet point of the cooling water channel into the converter module. The temperature of this inlet point is the inlet water temperature of the cooling water channel.

[0061] For example, the compensation unit 232 adds ΔQk to the heat quantity at the position of input to the model (Qigbt input to the model). This position corresponds to the position of the heat-generating element.

[0062] The compensation unit 232 may add all of ΔQi, ΔQj, and ΔQk, or add one or two of them. Preferably, in the case of estimating Twater, ΔQk is compensated directly to improve the accuracy of the estimate.

[0063] After the heat quantity is added by the compensation unit 232, the calculation unit 231 calculates the temperature at the individual positions based on the added heat quantity.

[0064] As a result, the difference ΔT between Tthermistor and Tthermistor_senseor becomes smaller, and consequently the estimation accuracy of the temperature and the heat quantity of the estimator 20 is increased.

[0065] By iteratively repeating the calculation processing by the calculation unit 231 and the compensation processing by the compensation unit 232, the estimation accuracy of temperature and heat quantity can be increased.

[0066] In the prior art, the temperature at the position of the heat generating element is sometimes used as a reference temperature (fixed value). As in Fig. 3 and Fig. 4, in the model of the first embodiment, the variable temperature node 301 is arranged at the position of the heat generating element.

[0067] Therefore, even if a temperature sensor cannot be installed sufficiently close to the heat generating element, according to the first embodiment, the temperature and heat quantity of the heat generating element can be estimated with high accuracy.

[0068] Based on Fig. 5, a processing flow of the estimation device 20 is described. Fig. 5 is a flowchart showing the processing flow of the estimation apparatus according to the first embodiment.

[0069] As in Fig. 5, the estimation device 20 first retrieves the model information 221 stored in the storage unit 22 and reads the model (step S101).

[0070] Then, the estimator 20 sets the reference temperature in the model (step S102). For example, Twater _in from Fig. 3 of the reference temperature. If a model as in Fig. 4 which does not have a reference temperature node, the estimator 20 may skip the step of setting the reference temperature.

[0071] The estimator 20 also sets the mass flow rate of the heat dissipation section in the model (step S103). For example, the estimator 20 sets the mass flow rate as a parameter of the mass flow-dependent thermal resistance and the mass flow-dependent variable temperature node.

[0072] Then, the estimator 20 inputs the heat quantity of the heat-generating element into the model (step S104). For example, Qigbt corresponds to the heat quantity of the heat-generating element. Then, the estimator 20 calculates the temperature at each position based on the input heat quantity (step S105).

[0073] In addition, the estimator 20 compensates the heat amount based on the difference between the calculated temperature (Tthermistor) and the detection temperature (Tthermistor_sensor) (step S106).

[0074] At this time, the estimator 20 judges whether a convergence condition is met (step S107). If the estimator 20 judges that the convergence condition is met (Yes in step S107), the processing ends. If the estimator 20 judges that the convergence condition is not met (No in step S107), it returns to step S105 and repeats the processing.

[0075] The convergence condition includes, for example, that the frequency of execution of steps S105 and S106 reaches a certain value, that the processing time reaches or exceeds a specified time, or that ΔT falls below a threshold value, or the like.

[0076] When the processing is completed, the estimator 20 may output the calculated temperature (or heat quantity) to the inverter device 10 or another device.

[0077] As explained above, the estimator 20 can estimate the temperature and heat quantity of any position as long as the thermal resistance, etc., are modeled. The positions for which the estimator 20 calculates the temperature can be, for example, as shown in Fig. 6 must be specified. Fig. 6 is an example arrangement of object positions.

[0078] As in Fig. As shown in Figure 6, the target positions are not limited to positions near the heat-generating elements, but can also be positions remote from the heat-generating elements. The target positions can also be intermediate areas between the phases. Fig. 6 shaded positions do not border on a heat generating element and are nevertheless positions at which the estimation device 20 can estimate the temperature and the amount of heat.

[0079] As in Fig. As shown in Figure 6, the positions of the temperature sensors include positions on the carrier that are not adjacent to heat-generating elements. The positions of the temperature sensors are not limited to positions on the carrier and can also be positions on the base plate, in the water channel, or in the cooling water, for example.

[0080] Fig. Figure 7 is an explanatory view of hotspots. Fig. Fig. 7 is a top sectional view of a heat dissipation fin of the inverter device (example of the heat dissipation section). As in the general example of Fig. As shown in Figure 7, the more strongly an area is colored (shaded), the higher the temperature.

[0081] As in Fig. 7, hot spots are formed by heat generated when the heat generated by the heat generating elements (e.g., IGBT and FWD) is dissipated at the heat dissipation portion (near the maximum temperature of the shaded part of Fig. 7).

[0082] The locations serving as target positions of the estimator 20 that are not adjacent to heat-generating elements include locations that are not hot spots (are cold spots). Therefore, the estimator 20 can estimate the temperature and heat quantity of the cold spots. The positions of the temperature sensors that are not adjacent to heat-generating elements are cold spots. By introducing cold spots, the estimation accuracy for hot spots can also be increased. As shown in Fig. 6, the positions at which the estimator 20 calculates the temperature can be located at both hot spots and cold spots. (Second embodiment)

[0083] Fig. Fig. 8 is a view showing a model of a second embodiment. As shown in Fig. 8, in the model of the second embodiment, the mass flow dependent node 308a was in the model of the first embodiment ( Fig. 4) with variable temperature is replaced by a reference temperature node 308.

[0084] The model of the second embodiment, like the model of the first embodiment, includes the compensation node 311. However, the mass flow-dependent variable temperature node 308a has been replaced by the reference temperature node 308, and at the corresponding position, no compensation-related change in the amount of heat occurs, which is why the compensation unit 232 is set to the Fig. 4, the compensation using the heat quantity ΔQj is omitted.

[0085] In this way, the estimation device 20 in the second embodiment can estimate the temperature and the heat quantity using compensation processing for both the reference temperature and the heat quantity. This compensation can improve the estimation accuracy. (Third embodiment)

[0086] Fig. 9 is a view showing a model of a third embodiment. As shown in Fig. 9, the model of the third embodiment was adapted to the model of the second embodiment ( Fig. 8) a compensation node 331 was added.

[0087] The detection temperature 402 (Twaterout_sensor) is input to the compensation node 331. The detection temperature 402 is a temperature detected by a temperature sensor provided on the outlet side of a water channel forming the heat dissipation section.

[0088] The compensation unit 232 first calculates ΔTa, which is the difference between Twater_out and Twaterout_sensor (detection temperature 402). Then, the compensation unit 232 performs PID control on ΔTa to obtain ΔQm.

[0089] For example, the compensation unit 232 adds ΔQm to the amount of heat at the position of input to the model (Qigbt input to the model).

[0090] The compensation unit 232 may also add both ΔQk and ΔQm to Qigbt.

[0091] In this way, the calculation unit 231 calculates the respective temperatures of the target positions from the model based on the heat quantity of the heat generating elements and the reference temperature (Twater_in) set at the position of the first end point on the heat generating element side of the heat dissipation section of the inverter device 10.

[0092] The compensation unit 232 further compensates the amount of heat used for the temperature calculated by the calculation unit 231 based on the difference between the temperature at the position of the second end point on the opposite side from the heat generating elements of the heat dissipation section (Twater_out) and the temperature detected by the temperature sensor provided at the second end point (Twaterout_sensor).

[0093] In the third embodiment, the estimation accuracy of the temperature and the heat quantity can be further increased by providing the compensation node. (Fourth embodiment)

[0094] Fig. 10 is a view showing a model of a fourth embodiment. As shown in Fig. 10, the model of the fourth embodiment was adapted to the model of the first embodiment ( Fig. 4) a filter 341 was added.

[0095] Filter 341 outputs a total heat quantity Qtotal_estimate of the model based on the heat quantity Qigbt. The calculation of filter 341 can be expressed, for example, as Qtotal_estimate = 1 / (1 + Ts) (ΣQi). Preferably, the filter is of the highest order possible. A time constant of the filter simulates a transfer time constant of the total heat quantity from the input heat quantity until it reaches the end point of the heat dissipation section.

[0096] For example, the total heat quantity Qtotal_estimate determines the temperature Twater_out on the outlet side of the water channel. The calculation unit 231 uses the heat quantity Qigbt and the temperature Twater_out to calculate the temperature of the variable-temperature nodes included in the model.

[0097] Thus, by filtering the heat quantities of the heat generating elements input into the model and thus calculating a sum of the heat quantities in the model (Qtotal_estimate), the calculation unit 231 calculates the temperature of the respective target positions based on the heat quantities of the heat generating elements (Qigbt) input into the model and the sum of the heat quantities.

[0098] In the fourth embodiment, the total heat quantity can thus be determined in advance by the filter 341, whereby the estimation accuracy of the temperature and the heat quantity can be further increased. (Fifth embodiment)

[0099] Fig. 11 is a view showing a model of a fifth embodiment. As shown in Fig. 1, in the case where the converter device 10 is designed with three phases, the thermal models for the individual phases can be combined.

[0100] In the example of Fig. 11, a single reference temperature node 352 is provided for the three phases.

[0101] For example, the compensation unit 232 compensates the heat amount of the variable temperature node 353a based on the difference between the detection temperature detected by the temperature sensor 121a and the temperature of the variable temperature node 351a calculated by the calculation unit 231.

[0102] The compensation unit 232 also compensates the heat amount of the variable temperature node 353b based on, for example, the difference between the detection temperature detected by the temperature sensor 121b and the temperature of the variable temperature node 351b calculated by the calculation unit 231.

[0103] Also, the compensation unit 232 compensates the heat amount of the variable temperature node 353c based on, for example, the difference between the detection temperature detected by the temperature sensor 121c and the temperature of the variable temperature node 351c calculated by the calculation unit 231.

[0104] Even if the configuration of the inverter device is complicated, the estimation device 20 can estimate the temperature and the heat quantity at each position by expressing it in the form of a model.

[0105] In the model of Fig. 11, there is no restriction on the number of cold spots such as Tbase_cold, and these can be any number. For example, in the heat dissipation section of Fig. 7, the accuracy is preferably increased by providing a cold spot for each phase. A temperature sensor such as a Tthermister is provided at at least one location. (Sixth embodiment)

[0106] Fig. 12 is a view showing an example of the configuration of an estimation system of a sixth embodiment. As shown in Fig. As shown in Figure 12, the compensation unit 232 in the estimation system 2 includes a ratio calculation unit 2321 and a PID control unit 2322. Furthermore, the estimation device 20 includes a heat quantity calculation unit 233. The estimated temperature output by the estimation device 20 is used to reduce the output power for the load such as the motor or the like.

[0107] The estimation device 20 is implemented by a part of a control CPU 23a. A power module main body 100 includes elements other than the control CPU 23a among the elements constituting the inverter device 10. For example, the power module main body 100 includes a substrate or the like on which heat-generating elements such as FWD and IGBT, a temperature sensor, and components are provided. The elements constituting the power module main body 100 are not limited to those mentioned above.

[0108] The control CPU 23a includes a duty cycle signal generation unit 2301. The duty cycle signal generation unit 2301 generates duty cycle signals from control signals (voltage command value, current sensor value, etc.) and inputs them to the power module main body 100.

[0109] The ratio calculation unit 2321 calculates the loss ratio of the heat-generating elements in the vicinity of the first position, which is the position where the heat quantity is compensated by the compensation unit 232, the ratio of the thermal resistances from the first position to the temperature sensor, or the ratio between the temperature of the first position and the temperature of the heat-generating elements. By thus considering the contribution of each element to the sensor temperature, the overall temperature can be evenly corrected, further improving the estimation accuracy of the heat quantity and temperature.

[0110] The PID control unit 2322 performs PID control on the difference between the temperature sensor detection value obtained from the power module main body 100 and the sensor temperature estimation value calculated by the calculation unit 231. For example, the PID control unit 2322 calculates ΔQi, ΔQj, or ΔQk ​​from Fig. 4 corresponding values.

[0111] The heat quantity calculation unit 233 calculates the heat quantity Qigbt of the heat generating elements. The heat quantity calculation unit 233 calculates the heat quantity as specified in Formula (4) of Patent Document 2.

[0112] The compensation unit 232 inputs a value x to the calculation unit 231, which is a multiplication of the PID correction amount calculated by the PID control unit 2322 and the ratio calculated by the ratio calculation unit 2321. The ratio calculation unit 2321 can calculate the ratio in the same method as the method of multiplying ΔQk by the ratio.

[0113] The calculation unit 231 calculates the temperature or the heat quantity based on x. For example, the calculation unit 231 outputs the estimated temperature of the heat-generating elements.

[0114] According to the estimation device 20 of the first embodiment, the temperature sensor 121a does not need to be in close contact with the heat-generating elements. Also, according to the estimation device 20, the heat quantity and temperature can be estimated at arbitrary positions of the individual parts of the inverter device 10.

[0115] Fig. 13 is a view of an example of the hardware configuration of the estimation device according to the first embodiment. As shown in Fig. 13, the estimation device 20 includes a computer with a processor 2010, a memory 2020, an input and output interface IF 2030 and a bus 2040. The processor 2010, the memory 2020 and the input and output interface IF 2030 can exchange information via the bus 2040.

[0116] The processor 2010 reads and executes an estimation program stored in the memory 2020 to perform the functions of the control unit 23. The processor 2010 is an example of the processing circuit and includes at least one of a CPU, a DSP (digital signal processor), and a system LSI (large-scale integration).

[0117] The memory 2020 includes at least one of RAM, ROM, flash memory, EPROM (erasable programmable read-only memory), and EEPROM (registered trademark) (electrically erasable programmable read-only memory). The input / output interface IF 2030 includes, for example, an AD converter, a DA converter, an input / output port, and the like.

[0118] A configuration is also possible in which the estimation device 20 includes a data readout unit that reads the estimation program from a data medium on which the computer-readable estimation program is recorded. The processor 2010 can control the data readout unit and acquire the estimation program recorded on the data medium from the data readout unit and store the acquired estimation program in the memory 2020. The data medium can include, for example, at least one of a non-volatile or volatile semiconductor memory, a magnetic disk, a flexible memory, an optical disk, a CD, and a DVD (digital versatile disc).

[0119] The estimation device 20 may include a communication unit that receives the estimation program from a server via a network. In this case, the processor 2010 may obtain the estimation program from the server via the communication unit and store the obtained estimation program in the memory 2020.

[0120] The control unit 23 of the estimation device 20 may include integrated circuits such as ASIC (application specific integrated circuit) and FPGA (field programmable gate array) and the like.

[0121] As discussed above, the estimation device 20 of the first embodiment includes the calculation unit 231 and the compensation unit 232. The calculation unit 231 calculates the respective temperatures of the target positions based on the heat quantity of the heat generation element or the heat quantity of the heat generation element and the mass flow rate of the heat dissipation section, using the model expressing the thermal resistance between target positions, which includes a thermal resistance between the position of a heat generating element and the position of a temperature sensor on the inverter device 10, or the model expressing the thermal resistance and the mass flow rate of a heat dissipation section. The compensation unit 232 compensates the heat quantity of the target positions based on the difference between the temperature of the temperature sensor position calculated by the calculation unit 231 and the temperature detected by the temperature sensor.As a result, the estimation device 20 can estimate the temperature, or the temperature and heat quantity, of the elements of the inverter device with high accuracy, particularly in cases where no temperature sensor is provided sufficiently close to the heat-generating elements of the inverter device. The estimated temperature is used to derate the output power for the load, such as the motor or the like.

[0122] The calculation unit 231 further calculates the respective temperatures of the target positions based on the temperature calculated with the heat quantity compensated by the compensation unit 232. This allows the estimation device 20 to further increase the estimation accuracy for the heat quantity and temperature.

[0123] Furthermore, the calculation unit 231 calculates the respective temperatures of the target positions based on the model expressing the thermal resistance, which includes the thermal resistance between two positions selected from target positions including the position of the heat-generating element (i.e., the switching element or the flywheel diode), a location not adjacent to the heat-generating element, an end point position of the heat dissipation portion provided on the inverter device 10, and the position of a temperature sensor. By using a model corresponding to the configuration of the inverter device 10, the estimation device 20 can estimate the temperature and heat quantity with high accuracy.

[0124] The compensation unit 232 compensates for at least one of the heat quantity at the position of the heat-generating element, the heat quantity at the end point position of the heat dissipation portion, and the heat quantity at the location not adjacent to a heat-generating element. In this way, the estimation device 20 can compensate for the heat quantity at a position according to the configuration of the inverter device 10, further increasing the estimation accuracy.

[0125] In this way, the calculation unit 231 calculates the respective temperatures of the target positions based on the model, based on the heat quantity of the heat-generating element and the reference temperature set for at least one of the target positions. In this way, the estimation device 20 can increase the estimation accuracy based on the reference temperature.

[0126] The calculation unit 231 calculates the respective temperatures of the target positions based on the model based on the heat quantity of the heat-generating elements and the reference temperature set at the position of the first end point on the heat-generating element side of the heat-dissipating section of the inverter device 10. The compensation unit 232 further compensates the heat quantity based on the difference between the temperature calculated by the calculation unit 231 at the position of the second end point on the opposite side from the heat-generating elements of the heat-dissipating section and the temperature detected by the temperature sensor provided at the second end point, which is used for the temperature calculated by the calculation unit 231. By providing multiple compensation nodes, the estimation device 20 can thus increase the estimation accuracy.

[0127] By filtering the heat quantities of the heat-generating elements input into the model and thus calculating a sum of the heat quantities in the model, the calculation unit 231 calculates the temperature of the respective target positions based on the heat quantities of the heat-generating elements input into the model and the sum of the heat quantities. In this way, the estimation device 20 can increase the estimation accuracy by using the sum of the heat quantities.

[0128] The compensation unit 232 adds the value obtained by multiplying the difference correction amount (e.g., the PID correction amount) by the loss ratio of the heat-generating elements in the vicinity of the first position, the ratio of the thermal resistances from the first position to the temperature sensor, or the ratio between the temperature of the first position and the temperature of the heat-generating elements to the heat quantity of the heat-generating elements at the first position. The influence of the distance from the heat-generating elements can thus be reflected in the compensation amount for each temperature sensor.

[0129] The above describes the case of applying the estimation device 20 of the first embodiment to the inverter device 10. The application object of the estimation device 20 may also be a power conversion device other than an inverter device, such as a converter device.

[0130] The estimation device 20 of the first embodiment can also acquire the temperature using a device other than a temperature sensor, such as a table or the like. For example, temperatures used for simulation can be set in the table. In this way, the estimation device 20 can be used as a simulator. [Second embodiment]

[0131] The arrangement of the nodes of the thermal model is not limited to the above description. In the second embodiment, nodes are arranged not only in the areas immediately below the heat-generating elements where high temperatures are prone to occur, but also in low-temperature parts away from the heat-generating elements.

[0132] Fig. 14 is a view showing an example of a thermal model according to the second embodiment. The power conversion device 5 of the second embodiment may be a similar device to the inverter device 10 of the first embodiment. However, the configuration of the thermal model is different between the first embodiment and the second embodiment. Fig. 14 is a sectional view of the current transformer device 5 (corresponds to the sectional view AA of Fig. 1), in which the heat is shown.

[0133] As in Fig. As shown in Figure 14, the power conversion device 5 includes a bus bar 501, an IGBT 502, a FWD 503, a temperature sensor 504, a bus bar 505, a support 506, a base plate 507, a space 508, and a heat sink 509. Refrigerant is present in the space 508. The positions designated 510 and 511 are end points of the heat sink (heat dissipation section). In the second embodiment, the refrigerant is water (cooling water).

[0134] As in Fig. 14, the thermal model includes a variable temperature node 521, a variable temperature node 522, a variable temperature node 523, a reference temperature node 524, and a variable temperature node 525.

[0135] The thermal model also includes a variable temperature node 531, a variable temperature node 532, a variable temperature node 533, a variable temperature node 534, and a variable temperature node 535 disposed on the base plate 507.

[0136] The thermal model has a thermal resistance 561, a thermal resistance 562, a thermal resistance 563, a thermal resistance 564, a thermal resistance 565, a thermal resistance 566, a thermal resistance 567 and a thermal resistance 568.

[0137] The thermal model has a mass flow dependent thermal resistance 569, a mass flow dependent thermal resistance 570, a mass flow dependent thermal resistance 571 and a mass flow dependent thermal resistance 572.

[0138] The thermal model has a mass flow dependent variable temperature node 541 and a mass flow dependent variable temperature node 542.

[0139] The reference temperature node, the variable temperature nodes, the mass flow rate dependent variable temperature node, the thermal resistors, and the mass flow rate dependent thermal resistors are defined as described in the first embodiment.

[0140] The variable temperature node 531, the variable temperature node 532, the variable temperature node 533, the variable temperature node 534, and the variable temperature node 535 arranged on the base plate 507 are not in contact with heat generating elements.

[0141] Because variable-temperature node 532 and variable-temperature node 533 are located immediately below a heat-generating element, they tend to have a high temperature. However, variable-temperature node 531, variable-temperature node 534, and variable-temperature node 535 are not located immediately below a heat-generating element, and therefore tend to have a lower temperature than the variable-temperature nodes located immediately below the heat-generating element.

[0142] The current transformer device 5 estimates not only the temperature at the parts with a tendency to high temperature (high-temperature parts), but also the parts with a tendency to low temperature (low-temperature parts). As shown in Fig. As shown in Figure 15, the heat model expresses the amount of heat as spreading in the surface direction by connecting the high-temperature parts and the low-temperature parts in a mesh-like manner using the thermal resistances. Fig. 15 is a view of an example of a thermal model according to the second embodiment. It shows the power conversion device 5 from above. Fig. 14 shows a sectional view along the line AA of Fig. 15.

[0143] In this way, the temperature gradient can be expressed in terms of area. The water temperature of water channel sections not adjacent to heat-generating elements rises and falls as a result of heat exchange with the water temperature wall. In this case, too, by arranging nodes on the water temperature wall, it is possible to express the temperature gradient by taking heat transfer into account.

[0144] Fig. 16 is a view showing an example of the configuration of the power conversion device according to the second embodiment. As shown in Fig. As shown in Figure 16, the current conversion device 5 is connected to a motor 71 via a current detection unit 72. The motor 71 is an example of the load.

[0145] A speed detection unit 73 detects the speed of the motor 71 and inputs it to the current conversion device 5. The current detection unit 72 detects the current of the motor 71 and inputs it to the current conversion device 5.

[0146] The power conversion device 5 is cooled by a heat sink 82. A flow path 81 is provided in the heat sink 82. A mass flow / water temperature detection unit 83 detects the flow rate and temperature of the cooling water flowing in the flow path 81 and inputs them to the power conversion device 5. The mass flow / water temperature detection unit 83 is a water temperature sensor and a flow rate sensor, each provided at at least one inlet or one outlet of the cooling water flow path.

[0147] The power conversion device 5 includes a control device 60, a converter main circuit 51, a gate driver circuit 52, a power supply circuit 53, and a carrier temperature detection unit 54.

[0148] The control device 60 is, for example, a microcomputer. The control device 60 has the same functions as the estimation device 20 of the first embodiment. The control device 60 controls the inverter main circuit 51.

[0149] The converter main circuit 51 is a circuit that causes the power conversion device 5 to operate as a converter. The gate driver circuit 52 is a circuit for controlling the converter main circuit 51. The power supply circuit 53 is a circuit for supplying electrical power to the converter main circuit 51. The carrier temperature detection unit 54 is a temperature sensor.

[0150] Fig. 17 is a view of an example of the configuration of the control device according to the second embodiment. As shown in Fig. As shown in Fig. 17, the control device 60 includes a motor control unit 61, an estimation unit 62, a derating control unit 63, and a PWM generation unit 64.

[0151] The motor control unit 61 generates voltage commands based on control commands (torque commands). The estimation unit 62 estimates the temperature of the heat-generating elements. The derating control unit 63 generates an output power restriction coefficient based on the temperature estimated by the estimation unit 62. For example, if the temperature estimated by the estimation unit 62 exceeds a threshold, the derating control unit 63 generates an output power restriction coefficient that causes the power conversion device 5 to derate.

[0152] The estimation unit 62 includes a heat quantity calculation unit 621 and a temperature estimation unit 622. The heat quantity calculation unit 621 and the temperature estimation unit 622 perform similar processing to the calculation unit 231 and the compensation unit 232 of the first embodiment.

[0153] The heat quantity calculation unit 621 calculates the heat quantity of the heat generating elements based on the load information. The load information includes, for example, the rotational speed of the motor 71, a switching frequency, and current. The temperature estimation unit 622 calculates the temperature of the nodes and heat generating elements of the thermal model. For example, the temperature estimation unit 622 calculates the temperature of the heat generating elements based on the carrier temperature, which is a sensor value, the inlet water temperature of the cooling water, and the flow rate of the cooling water, in addition to the heat quantity calculated by the heat quantity calculation unit 621.

[0154] Fig. 18 is a view showing an example of the configuration of the temperature estimation unit according to the second embodiment. As shown in Fig. 18, the temperature estimation unit 622 includes a thermal resistance calculation unit 6221, a refrigerant temperature calculation unit 6222, a base plate temperature calculation unit 6223, and a heat generating element temperature calculation unit 6224.

[0155] The thermal resistance calculation unit 6221 calculates the resistance value of the thermal resistance based on the flow rate and temperature of the cooling water in a thermal model that expresses the heat transfer between two different points (two nodes) of a heat-generating element, the base plate 507, the support 506, and cooling water (an example of the refrigerant) as thermal resistance. Here, points on bodies mean points on the surface and inside of the body in question. For example, a point on the base plate 507 is a point on the base plate 507, the surface, and the inside. Therefore, the thermal model can be said to be a model that expresses the heat transfer between two different points on the surface and inside of a heat-generating element, the base plate 507, the support 506, and the cooling water, as thermal resistance.In still other words, the thermal model is a model that expresses the heat transfer between two different points selected from points that may exist on the surface and inside of a heat generating element, the base plate 507, the support 506, and the cooling water, as thermal resistance.

[0156] Through 3D heat flow analysis, a table is provided in advance indicating the relationship between water temperature, flow rate, and thermal resistance. The thermal resistance calculation unit 6221 can use the table to calculate the thermal resistance from the water temperature and flow rate.

[0157] For example, the thermal resistance calculation unit 6221 calculates the thermal resistance R th conv1 (V,T) of the mass flow dependent thermal resistance 569, the thermal resistance R th conv2 (V,T) of the mass flow dependent thermal resistance 570, the thermal resistance R th conv3(V,T) of the mass flow dependent thermal resistance 571 and the thermal resistance R th conv4 (V,T) of the mass flow dependent thermal resistance 572. V and T represent the flow rate and the temperature, respectively.

[0158] The mass flow-dependent thermal resistance expresses the heat transfer from the base plate 507 and heat dissipation fins on the base plate 507 to the cooling water. Thus, the temperature estimation unit 622 can calculate transient temperature changes by setting a heat capacity (node) between each node of the thermal model and the reference temperature, thus forming a CR circuit. Setting the heat capacity is optional, and if no transient temperature changes are required and steady-state temperature changes are calculated, an R circuit without C is possible.

[0159] The refrigerant temperature calculation unit 6222 calculates the temperature due to the heat transfer of the cooling water based on the flow characteristics of the cooling water, which change due to the amount of heat absorbed by the heat-generating elements, the support, or the base plate, the flow rate of the refrigerant, the temperature at the end points of the cooling water flow path, and the temperature of the cooling water. The refrigerant temperature calculation unit 6222 calculates the temperature T using formula (1). wtr of the node corresponding to the cooling water (for example, the mass flow-dependent variable-temperature node 542). Where ρ and c represent the density and specific heat of the cooling water, respectively. [Equation 1] Twtr=Qwtr_allρ(Twtr)∗c(Twtr)∗V+Twtr_in

[0160] As shown in formula (1), the refrigerant temperature calculation unit 6222 adds to the inlet temperature T wtr_inthe increase in water temperature (in formula (1) the first term on the right-hand side).

[0161] The base plate temperature calculation unit 6223 calculates the temperature of the base plate 507 based on the heat quantity and the thermal resistance.

[0162] The base plate temperature calculation unit 6223 can calculate the temperature of the variable temperature node 531 from the variable temperature node 531 and the variable temperature node 532. The variable temperature node 531 is a node at the low-temperature part of the base plate 507 and is a node that is not adjacent to a heat-generating element.

[0163] The base plate temperature calculation unit 6223 can calculate the temperature of the variable temperature node 532 among the variable temperature node 531 and the variable temperature node 532. The variable temperature node 532 is a node at the high-temperature part of the base plate 507 and is a node adjacent to a heat generating element.

[0164] The base plate temperature calculation unit 6223 calculates the temperature T using formula (2) base a node of the base plate 507 connected to the mass flow dependent thermal resistor (for example, the variable temperature node 533). [Equation 2] Tbase=Qbase_wtrRbase−wtr(V,Twtr)+Twtr

[0165] As shown in formula (2), the base plate temperature calculation unit 6223 adds to the water temperature T wtr the increase in temperature (in formula (2) the first term on the right-hand side).

[0166] The heat-generating element temperature calculation unit 6224 calculates the temperature of the heat-generating elements based on the heat quantity and the temperature of the base plate 507. The heat-generating element temperature calculation unit 6224 calculates the temperature Tigbt of a heat-generating element (for example, the temperature T element2 of node 533 with variable temperature). [Equation 3] Tigbt=Wigbt_baseRigbt−base+Tbase

[0167] As shown in formula (3), the heat generating element temperature calculation unit 6224 adds to the temperature T base of the node of the base plate 507 the increase in temperature (in formula (3) the first term on the right side).

[0168] Like the compensation unit 232 of the first embodiment, the temperature estimation unit 622 compensates one or more of the heat amount, the cooling water temperature, the flow rate, and the thermal resistance based on the difference between the temperature of the position of the temperature sensor calculated by the base plate temperature calculation unit 6223 and the temperature detected by the temperature sensor.

[0169] Based on Fig. 19, a processing flow of the power conversion device 5 of the second embodiment will be described. Fig. 19 is a flowchart showing the processing flow of the power conversion device according to the second embodiment.

[0170] As in Fig. As shown in Figure 19, the power conversion device 5 first detects the three-phase current value (step S201). The power conversion device 5 detects the rotational speed of the motor 71 (step S202). Then, the power conversion device 5 calculates the electrical energy loss (heat amount) based on the three-phase current value and the rotational speed of the motor 71 (step S203).

[0171] Next, the power conversion device 5 detects the flow rate of the cooling water (step S204). Then, the power conversion device 5 calculates the thermal resistance value of the thermal model based on the flow rate (step S205).

[0172] Subsequently, the current conversion device 5 detects the inlet temperature of the cooling water (step S206). The current conversion device 5 then calculates the temperature of the cooling water based on the inlet temperature (step S207).

[0173] Next, the power conversion device 5 calculates the temperature of the base plate based on the temperature of the cooling water (step S208). The power conversion device 5 also calculates the temperature of the heat-generating elements based on the temperature of the base plate (step S209).

[0174] The current transformer device 5 compensates the heat quantity based on the difference between the calculated temperature and the detection temperature (step S210).

[0175] At this time, the power conversion device 5 judges whether a convergence condition is met (step S211). If the power conversion device 5 judges that the convergence condition is met (Yes in step S211), the processing ends. If the power conversion device 5 judges that the convergence condition is not met (No in step S211), it returns to step S204 and repeats the processing.

[0176] The convergence condition includes, for example, that the frequency of execution of step S210 reaches a certain value, that the processing time reaches or exceeds a specified time, or that the compensation amount falls below a threshold value, or the like.

[0177] Generally, there is an imbalance in the heat generation of the U, V, and W phase elements of a converter during stall or low-speed motor rotation. When the motor is stalled, more current flows through the elements of one phase than through the elements of the other two phases, which is why the amount of heat generated is concentrated in one phase. When the elements of the converter main circuit are arranged closely together, the heat transfer pattern to the cooling water changes compared to when the motor is rotating at a sufficiently high speed, which can lead to a decrease in the accuracy of temperature estimation at the junctions between the elements of the converter main circuit.

[0178] In the second embodiment, the heat transfer mode to the cooling water is modeled, thereby increasing the estimation accuracy of the temperature of the heat-generating elements. In the second embodiment, the nodes are arranged not only in the high-temperature parts adjacent to the heat-generating elements, but also in the low-temperature parts, thus increasing the estimation accuracy of the temperature of the heat-generating elements.

[0179] In a method that compares the estimated value of a temperature sensor and an actual sensor value, and establishes an observer that corrects the losses occurring or the temperature of each part of the thermal model, the temperature of the elements is accurately estimated. If the temperature estimation accuracy of the temperature sensor is low, the correction will not work. However, according to the second embodiment, if the estimation accuracy of the temperature of the heat-generating elements is increased, a proper correction function is achieved.

[0180] According to the current transformer device 5 as shown in Fig. As shown in Figure 14, in the second embodiment, the temperature sensor 504 does not need to be in close contact with the heat-generating elements. Also, according to the power conversion device 5, the heat quantity and temperature can be estimated at any position of the individual parts of the power conversion device 5. [Third Embodiment]

[0181] In a third embodiment, a water channel is also modeled by the thermal model. In the third embodiment, the density ρ and the specific heat c, the parameters of formula (1) sin, are calculated according to the temperature of the cooling water.

[0182] Fig. 20 is a view showing an example of the configuration of the temperature estimation unit according to the third embodiment. As shown in Fig. 20, the temperature estimation unit 622 of the third embodiment includes, in addition to the configuration elements of the temperature estimation unit of the second embodiment, a unit 6225 for calculating the physical values ​​of the refrigerant.

[0183] The refrigerant physical value calculation unit 6225 calculates physical values ​​of the cooling water. The physical values ​​are the density ρ and the specific heat c. The refrigerant physical value calculation unit 6225 calculates the density ρ and the specific heat c using a table relating the water temperature to the density and specific heat, based on the water temperature calculated by the refrigerant temperature calculation unit 6222. The density ρ and the specific heat c calculated by the refrigerant physical value calculation unit 6225 are used as parameters of formula (1).

[0184] In the third embodiment, the thermal model is configured according to the shape of the water channel. Specifically, the thermal model expresses the thermal resistance due to heat transfer according to the shape of the cooling water channel.

[0185] Water channels of different shapes include, for example, winding water channels and straight water channels. Fig. 21 is an explanatory view of a winding water channel. Fig. 22 is an explanatory view of a straight water channel. In Fig. 21 and Fig. 22, the display form of heat capacities (nodes) immediately below a heat generating element and not adjacent to a heat generating element is changed.

[0186] The refrigerant temperature calculation unit 6222 calculates the water temperature based on a thermal model including temperature nodes of the refrigerant and temperature nodes of the casing body of the water channel.

[0187] The thermal model has a two-point convection connection between the heat generating element, the support or the base plate and the refrigerant, the two-point convection connection including the refrigerant temperature node immediately below the heat generating element, the support or the base plate temperature node and the heat generating element, the support or the base plate temperature node connected to the two refrigerant temperature nodes one further upstream.

[0188] As in Fig. 21 and Fig. As shown in Figure 22, the thermal resistance due to heat transfer between the nodes differs in direction and position depending on the shape of the water channel.

[0189] Based on Fig. 23, a processing flow of the power conversion device 5 of the third embodiment will be described. Fig. 19 is a flowchart showing the processing flow of the power conversion device according to the second embodiment.

[0190] As in Fig. As shown in Figure 23, the power conversion device 5 first detects the three-phase current value (step S301). The power conversion device 5 detects the rotational speed of the motor 71 (step S302). Then, the power conversion device 5 calculates the electrical energy loss (heat amount) based on the three-phase current value and the rotational speed of the motor 71 (step S303).

[0191] Next, the power conversion device 5 detects the flow rate of the cooling water (step S304). Then, the power conversion device 5 calculates the thermal resistance value of the thermal model based on the flow rate and the estimated cooling water temperature (step S305).

[0192] Subsequently, the power conversion device 5 calculates the physical values ​​of the cooling water (step S306-1). The power conversion device 5 detects the inlet temperature of the cooling water based on the calculated physical values ​​(step S306-2). Then, the power conversion device 5 calculates the temperature of the cooling water based on the inlet temperature (step S307).

[0193] Next, the power conversion device 5 calculates the temperature of the base plate based on the temperature of the cooling water (step S308). The power conversion device 5 also calculates the temperature of the heat-generating elements based on the temperature of the base plate (step S309).

[0194] The current transformer device 5 compensates the heat quantity based on the difference between the calculated temperature and the detection temperature (step S310).

[0195] At this time, the power conversion device 5 judges whether a convergence condition is met (step S311). If the power conversion device 5 judges that the convergence condition is met (Yes in step S311), the processing ends. If the power conversion device 5 judges that the convergence condition is not met (No in step S311), it returns to step S304 and repeats the processing.

[0196] Depending on the shape of the cooling channel, unintended rises and falls in water temperature may occur. For example, if the cooling water channel is tortuous, discrepancies between adjacent water temperatures may occur due to the transfer of heat flow from the water wall, resulting in a decrease in the water temperature estimation accuracy.

[0197] The water channel is heated from multiple directions, so that when large amounts of heat are applied, there is no temperature boundary layer, resulting in discrepancies in the water temperature distribution. As a result, the estimation accuracy of the base plate temperature, which is calculated from the water temperature, and the element temperature decreases.

[0198] In the third embodiment, the heat is configured according to the shape of the water channel, so that a decrease in the estimation accuracy can be prevented.

[0199] The disclosed embodiments are to be considered in all respects as exemplary and not restrictive. Indeed, the above embodiments may be implemented in a variety of ways. The above embodiments may be subject to various omissions, substitutions, and changes without departing from the scope and spirit of the appended claims.

[0200] Thermal resistance includes thermal conduction resistance, heat transfer resistance, and heat convection resistance. Thermal conduction resistance indicates the heat transfer between two different points on the heat-generating element, base plate, support, or refrigerant. Thermal convection resistance indicates the heat transfer via convection between two different points on the heat-generating element, base plate, support, or refrigerant.

[0201] Based on the definition of thermal conduction resistance and thermal convection resistance, the operation of the thermal resistance calculation unit 6221 can also be expressed as follows. The thermal resistance calculation unit 6221 calculates the resistance value of the thermal resistance based on the flow rate and temperature of the refrigerant in a thermal model that expresses heat transfer between two different points under a heat-generating element, base plate, support, or refrigerant as thermal conduction resistance, heat transfer at two different points of the refrigerant as heat transport, and heat transfer by convection between two different points under a heat-generating element, base plate, support, or refrigerant as thermal convection resistance.

[0202] The method for estimating temperature using the power conversion device 5 of the second embodiment and the third embodiment can also be applied to the thermal model described in the first embodiment. Therefore, the following configurations can be achieved based on each embodiment. (1) Configuration corresponding to the heat model in FIG. 3

[0203] The control device 60 of the power conversion device 5 has the heat quantity calculation unit 621, the refrigerant temperature calculation unit 6222 and the thermal model which calculates the temperature of the heat generating elements based on the heat quantity, flow rate and temperature of the refrigerant, wherein the thermal model includes a first variable temperature node (301), a first thermal resistance (302), a second thermal resistance (303), a second variable temperature node (304), a third thermal resistance (305), a third variable temperature node (306), a first mass flow-dependent thermal resistance (307), a reference temperature node (308), a second mass flow-dependent thermal resistance (309) and a mass flow-dependent variable temperature node (310). (2) Configuration corresponding to the heat model in FIG. 4

[0204] In the current transformer device 5 of (1), the reference temperature node of the thermal model is a mass flow-dependent variable temperature node. The thermal model further comprises a compensation node (311). (3) Configuration corresponding to the heat model in FIG. 8

[0205] In the current transformer device 5 of (1), the thermal model further comprises a compensation node (311). (4) Configuration corresponding to the heat model in FIG. 9

[0206] In the power conversion device 5 of (1), the thermal model further comprises a first compensation node (311) and a second compensation node (331). (5) Configuration corresponding to the heat model in FIG. 10

[0207] In the current transformer device 5 of (1), the reference temperature node of the thermal model is a mass flow-dependent variable temperature node. The thermal model further comprises a compensation node (311) and a filter (341) that simulates a heat transfer coefficient. (6) Configuration corresponding to the heat model in FIG. 11

[0208] The current transformer device 5 of (1) has three thermal models, wherein the three thermal models correspond to the three phases, respectively.

[0209] The control device 60 of the second embodiment and the third embodiment can be implemented by integrating in a computer the control device 60 according to Fig. The configuration described in (13) causes the execution of the program listed in (7) below. In this case, the computer executes the procedure of (8).

[0210] (7) A program for calculating a temperature with respect to a current transformer device comprising a base plate, a support provided on the base plate, a heat generating element and a temperature sensor provided on the support, and a control unit, and connected to a load, characterized by: a heat quantity calculation process that calculates a heat quantity of the heat generating element based on information about the load, a refrigerant temperature calculation process that calculates a temperature of the refrigerant based on a flow rate of a refrigerant cooling the heat generating element, a thermal resistance calculation procedure that calculates a thermal resistance value based on the flow rate and temperature of the refrigerant in a thermal model that expresses the heat transferred between two different points under the heat generating element, the base plate, the support and the refrigerant as thermal resistance, a base plate temperature calculation process that calculates a base plate temperature based on the heat quantity and the thermal resistance, and a heat generating element temperature calculation process that calculates a heat generating element temperature based on the heat quantity and the base plate temperature.

[0211] (8) A method for calculating a temperature with respect to a power conversion device comprising a base plate, a support provided on the base plate, a heat generating element and a temperature sensor provided on the support, and a control unit, and connected to a load, characterized in that it comprises: a heat quantity calculation step in which a heat quantity of the heat generating element is calculated based on information about the load, a refrigerant temperature calculation step in which a temperature of the refrigerant is calculated based on a flow rate of a refrigerant cooling the heat generating element, a thermal resistance calculation step in which a resistance value of the thermal resistance is calculated based on the flow rate and the temperature of the refrigerant in a thermal model that expresses the heat transferred between two different points under the heat generating element, the base plate, the support and the refrigerant as thermal resistance, a base plate temperature calculation step in which a base plate temperature is calculated based on the heat quantity and the thermal resistance, and a heat generating element temperature calculating step that calculates a heat generating element temperature based on the heat quantity and the base plate temperature by a computer. EXPLANATION OF REFERENCE SYMBOLS 1, 2 estimation system 5 Current transformer device 10 Converter device 20 Estimating device 21 Input and output unit 22 storage unit 23 Tax Section 51 Inverter main circuit 52 Gate driver circuit 53 Power supply circuit 54 Carrier temperature detection unit 61 Engine control section 62 estimation unit 63 Reduction control unit 64 PWM generation unit 71 Engine 72 Current measuring unit 73 Speed ​​detection unit 81 flow channel 82 heat sink 83 Mass flow / water temperature recording unit 60 Control device 221 model information 231 Calculation section 232 compensation unit 233 Heat quantity calculation unit 301, 304, 306, 351a, 351b, 351c, 353a, 353b, 353c, 521, 522, 523, 525, 531, 532, 533, 534, 535 Variable temperature nodes 302, 303, 305, 561, 562, 563, 564, 565, 566, 567, 568 Thermal resistance 307, 309, 569, 570, 571, 572 mass flow dependent thermal resistance 308, 352, 524 Reference temperature nodes 308a, 310, 541, 542 Mass flow dependent node with variable temperature 311, 331 compensation nodes 341 filters 401, 402 Detection temperature 501 Busbar 502 IGBT 503 FWD 504 Temperature sensor 505 busbar 506 circuit board 507 base plate 508 Room 509 heat sink 621 Heat quantity calculation unit 622 Temperature estimation unit 2321 Ratio calculation unit 2322 PID control unit 6221 Thermal resistance calculation unit 6222 Refrigerant temperature calculation unit 6223 Base plate temperature calculation unit 6224 Heat generating element temperature calculation unit 6225 Unit for calculating the physical values ​​of the refrigerant QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2011-97812 A

[0005]

Claims

[1] A current transformer device comprising a base plate, a support provided on the base plate, a heat generating element and a temperature sensor provided on the support, and a control unit, and connected to a load, characterized by , that: the control unit includes: a heat quantity calculation unit that calculates a heat quantity of the heat generating element based on information about the load, a refrigerant temperature calculation unit that calculates a temperature of the refrigerant based on a flow rate of a refrigerant cooling the heat generating element, a thermal resistance calculation unit that calculates a thermal resistance value based on the flow rate and temperature of the refrigerant in a thermal model that represents the heat transferred between two different points under the heat generating element, the base plate, the support and the refrigerant as thermal resistance, a base plate temperature calculation unit that calculates a temperature of the base plate based on the heat quantity and the thermal resistance, and a heat generating element temperature calculating unit that calculates a heat generating element temperature based on the heat quantity and the base plate temperature. [2] Current transformer device according to claim 1, further characterized bya compensation unit that compensates for one or more of the heat quantity, the refrigerant temperature, the flow rate, and the thermal resistance based on the difference between the temperature of the temperature sensor position calculated by the base plate temperature calculation unit and the temperature detected by the temperature sensor. [3] Current transformer device according to claim 1 or 2, further characterized by a refrigerant property value calculation unit that calculates a physical value of the refrigerant, wherein the refrigerant temperature calculation unit calculates the temperature of the refrigerant based on the flow rate of the refrigerant, the temperature of the refrigerant and the physical value of the refrigerant, wherein the thermal resistance calculation unit calculates the resistance value of the thermal resistance based on the flow rate and the temperature of the refrigerant in a thermal model that expresses the heat transfer between the two points and a heat transport due to the flow of the refrigerant as thermal resistance. [4] Current transformer device according to one of claims 1 to 3, characterized by that the base plate temperature calculation unit calculates the temperature of a location that is not adjacent to the heat generating element of the base plate. [5] Current transformer device according to one of claims 3 or 4, characterized by that the refrigerant temperature calculation unit calculates the water temperature based on a thermal model including temperature nodes of the refrigerant and temperature nodes of a casing body of a water channel. [6] Current transformer device according to claim 5, characterized bythat the thermal model has a two-point convection connection between the heat generating element, the support or the base plate and the refrigerant, the two-point convection connection including the temperature node of the refrigerant immediately below the temperature node of the heat generating element, the support or the base plate and the temperature node of the heat generating element, the support or the base plate which is connected to the two temperature nodes of the refrigerant one further upstream. [7] A current transformer device comprising a base plate, a support on the base plate, a heat generating element and a temperature sensor provided on the support, and a control unit, and connected to a load, characterized by , that: the control unit includes: a heat quantity calculation unit that calculates a heat quantity of the heat generating element based on information about the load, a refrigerant temperature calculation unit that calculates a temperature of the refrigerant based on a flow rate of a refrigerant cooling the heat generating element, and a heat model that calculates the temperature of the heat generating element based on the heat quantity, the flow rate and the temperature of the refrigerant, wherein the thermal model includes a first variable temperature node, a first thermal resistance, a second thermal resistance, a second variable temperature node, a third thermal resistance, a third variable temperature node, a first mass flow dependent thermal resistance, a reference temperature node, a second mass flow dependent thermal resistance, and a mass flow dependent variable temperature node. [8] Current transformer device according to claim 7, characterized by that the heat model also has a compensation node. [9] Current transformer device according to claim 7, characterized by that the reference temperature node is a mass flow dependent variable temperature node, wherein the heat model further comprises a compensation node and a filter simulating a heat transfer coefficient. [10] Current transformer device according to claim 5, characterized by that it has three heat models, each of which corresponds to three phases. [11] An estimation program that, on a power conversion device, uses a model that expresses the thermal resistance between target positions, which includes a thermal resistance between the position of a heat generating element and the position of a temperature sensor on the converter device, or a model that expresses the thermal resistance and the mass flow rate of a heat dissipation section, to cause a computer to execute a calculation process that calculates the respective temperatures of the target positions based on the heat quantity of the heat generating element or the heat quantity of the heat generating element and the mass flow rate of the heat dissipation section, and a compensation process that compensates the heat quantity of the target positions based on the difference between the temperature of the temperature sensor position calculated in the calculation process and the temperature detected by the temperature sensor. [12] Estimation program according to claim 11, characterized by that the position of the temperature sensor includes a position on a support that is not adjacent to the heat generating element. [13] Estimation program according to claim 11 or 12, characterized by that the temperature of the respective target positions is calculated based on the temperature calculated with the amount of heat compensated in the compensation process. [14] Estimation program according to one of claims 11 to 13, characterized by that the compensation process adds a value from multiplying a PID correction amount for the difference by a loss ratio of the heat generating element in the vicinity of the first position, the ratio of the thermal resistance from the first position to the temperature sensor, or the ratio between the temperature of the first position and the temperature of the heat generating element to the heat amount of the heat generating element at the first position. [15] Estimation program according to one of claims 11 to 13, characterized by that the compensation process adds the value from a multiplication of a correction amount for the difference by a loss ratio of the heat generating element in the vicinity of the first position, a ratio of the thermal resistance from the first position to the temperature sensor or a ratio between the temperature of the first position and the temperature of the heat generating elements to the heat amount of the heat generating element at the first position. [16] Estimation program according to one of claims 11 to 15, characterized bythat the calculation process calculates the respective temperatures of the target positions using a model expressing the thermal resistance including the thermal resistance between two positions selected from target positions including the position of the heat generating element, that is, a switching element or a flywheel diode, a location not adjacent to the heat generating element, an end point position of a heat dissipation portion provided on the power conversion device, and the position of a temperature sensor. [17] Estimation program according to claim 16, characterized by that the position not adjacent to the heat generating element includes a position that is not a hot spot formed by heat generated by dissipating the heat generated by the heat generating element at the heat dissipation portion. [18] Estimation program according to one of claims 11 to 17, characterized bythat the calculation process calculates the respective temperature of the target positions using the model based on the heat quantity of the heat generating element and a reference temperature set for at least one of the target positions. [19] Estimation program according to one of claims 11 to 18, characterized by that the calculation process filters the heat quantity of the heat generating element entered into the model and thus calculates a sum of the heat quantities in the model and calculates the temperature of the respective target positions based on the heat quantity of the heat generating element entered into the model and the sum of the heat quantity. [20] Estimation method using a model expressing the thermal resistance between target positions, which includes a thermal resistance between the position of a heat generating element and the position of a temperature sensor on the converter device, or a model expressing the thermal resistance and mass flow rate of a heat dissipation section on a power conversion device, characterized by : a calculation step in which the respective temperature of the target positions is calculated based on the heat quantity of the heat generating element or the heat quantity of the heat generating element and the mass flow rate of the heat dissipation section, and a compensation step in which the heat quantity of the target positions is compensated based on the difference between the temperature of the temperature sensor position calculated in the calculation process and the temperature detected by the temperature sensor.

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