Exemplar-specific storage of thermal and electrical properties of power semiconductor circuits in order to control same, and control device and product for the exemplar-specific operation of the power semiconductor circuits

Abstract

In order to detect and store individual properties of power semiconductor circuits (EX), at least one individual electrical property (RON) and at least one individual heat conduction property (RT) are first detected as individual properties of the individual power semiconductor circuits (EX42, EX43) after the production process and before the installation of the power semiconductor circuits into a product (P). The properties are stored in a memory (M) individually for each exemplar (EX42, EX43) of the power semiconductor circuits (EX). The memory (M) can be accessed by a controller (C) of the respective power semiconductor circuit during the operation of the power semiconductor circuits. The invention further relates to a corresponding control device and to a product which use the individual properties thus provided.

Description

[0001] 202401590

[0002] 1

[0003] Description

[0004] Specimen-specific storage of thermal and electrical properties of power semiconductor circuits for their control and control device, as well as a product for the specimen-specific operation of the power semiconductor circuits.

[0005] Power semiconductors such as MOSFETs, IGBTs, or triacs are used to control currents. Since these represent a significant cost factor, it is desirable to fully utilize their current-carrying capacity. At the same time, it must be ensured that maximum temperatures or maximum currents (i.e., given maximum values) are not exceeded.

[0006] For this purpose, appropriate power semiconductor circuits are designed accordingly during the dimensioning of the power semiconductors, in particular depending on the application and on the electrical and thermal properties of the power semiconductor structure and its thermal connection.

[0007] Therefore, the dimensioning of power semiconductor circuits depends on the application and also on the selected power semiconductor component.

[0008] To operate as close as possible to the performance limit without exceeding the maximum values, thermal models are used that simulate the power semiconductor circuits. Based on the expected thermal power, which results from the component-specific power dissipation, the thermal model determines the current (thermal) state of the power semiconductors in the circuit in order to derate them (reduce the maximum permissible power) if necessary. Predicted thermal states can also be generated in the same way.

[0009] However, with regard to the costs of power semiconductors, it is desirable to determine the thermal states of power semiconductors more precisely in order to enable higher power outputs if necessary.

[0010] This problem is solved by the subject matter of claim 1. Further applications, properties, features, embodiments and advantages become apparent with regard to the dependent claims, the description and the figure. 202401590

[0011] 2

[0012] It has been recognized that considering the electrical and thermal properties of power semiconductor circuits on a sample-specific basis enables higher power outputs for individual power semiconductor circuits or power semiconductors. In particular, this makes it possible to reduce the safety margin to the nominal maximum values, which is caused by sample variations (tolerances), when designing and implementing protective measures against excessive temperatures. In other words, a power semiconductor circuit no longer needs to be designed according to the maximum detrimental component tolerance (of the relevant datasheet). Instead, each individual semiconductor circuit can be operated according to the properties specific to that particular sample of the circuit.The operation with regard to maximum thermal and electrical properties is therefore not based on the component-type-specific values ​​of the data sheet, but on the specific, i.e. individual, properties of the circuit in question.

[0013] It is therefore planned to record the individual thermal and electrical properties of power semiconductor circuits directly after their manufacture, i.e., at the end of the production line. Such properties are usually only used to identify and reject non-functional circuits after production. However, this proposal suggests using these (already recorded) individual properties for later operation as well. To this end, these individual, component-specific properties are not only recorded but also stored (in memory) for later use. With these individual properties, a thermal model used in operation can be applied on a component-specific basis, i.e., individually for a particular instance of a power semiconductor circuit. For advantageously designed components, higher performance can therefore be achieved, instead of merely on a component-specific basis (i.e.,to model (type-dependent). The instance variation, which must be considered as a safety tolerance in component-specific modeling, is thereby partially or completely obsolete. Depending on the individual properties, the thermally or electrically permissible operating range can thus be extended up to the instance-specific limit. Power semiconductor circuits that are individually less robust (compared to other instances of the same component) are not overloaded, i.e., not operated in a range that would be possible according to the tolerances for this component (component type), 202401590.

[0014] 3. However, this would lead to problems specific to each individual component. Here, the terms "component" or "component type" refer to specific types or manufacturer-specific versions of semiconductors, as specified in the datasheet. These terms are not intended to denote a specific or individual component, but only the type of component.

[0015] A method for recording and capturing individual properties of power semiconductor circuits is described. It is intended to capture at least one individual (i.e., instance-specific) electrical property of a particular instance of a power semiconductor circuit. Furthermore, at least one individual (i.e., instance-specific) thermal property (heat conductivity property) of a particular instance of a power semiconductor circuit is captured. These properties are captured as individual properties, i.e., specific to an individual instance of a power semiconductor circuit. This is performed particularly for multiple power semiconductor circuits if they are to be operated together. The power semiconductor circuits in question, or the power semiconductors thereof, may have individual markings for this purpose. The markings chosen in Figure 1 are examples in EX42 and EX43.The individual properties of the power semiconductor circuits are recorded after their manufacture and before further use (i.e., integration) into a product. Specifically, these properties are recorded at the end of the production line (EOL), particularly during individual functional testing at the end of manufacturing. For multiple circuits, the individual properties of each circuit are preferably recorded at the end of its production run. In particular, the properties thus recorded are compared with relevant standard ranges, and the power semiconductor circuit in question is rejected if the standard ranges are not met. In other words, defective power semiconductor circuits are rejected based on their individually recorded properties. Preferably, however, these properties are reused, especially during the subsequent operation of the circuits.To enable this, the properties are individually stored in a memory for each instance of the power semiconductor circuits. This memory, in which the properties are stored on a per-specimen basis (individually for each instance), is capable of providing the properties after the power semiconductor circuits have been installed in a product. The memory thus retains the individual properties for later retrieval (retrieval after installation). Specifically, the memory is configured with the properties 202401590.

[0016] 4

[0017] (specific power semiconductor circuits) to be kept retrievable for a control device that controls these instances of the power semiconductor circuits. The memory thus not only preserves the properties for later statistical purposes in the evaluation of lifetime, for example, but also stores the properties on an instance-specific basis for later querying by a control device that controls these instances.

[0018] A power semiconductor circuit as described herein comprises at least one power semiconductor with a semiconductor area, (optionally) a housing for (each) power semiconductor (in particular a semiconductor switch), a mounting element (one or more parts), and a substrate. In the case of multiple power semiconductors, preferably at least one mounting element is provided for each power semiconductor. The mounting elements connect the semiconductors to the substrate. The mounting elements can be one or more parts. The mounting elements are in particular provided by a solder layer or a sintered layer. The substrate can have at least one electrically conductive layer and at least one insulating body. The power semiconductors are connected to the conductive layer (such as a conductor track or a conductive insert) of the substrate via the mounting elements. The circuit may also include a heat sink.These substrates can accommodate one or more power semiconductors. This creates heat conduction paths between the power semiconductors as the heat source and the substrate or heat sink. The thermal conductivity properties are determined individually for each power semiconductor circuit, and specifically for each heat path and each power semiconductor within the circuit. Thermal conductivity properties such as thermal conductivity or structural characteristics (layer thickness, air inclusions) that influence thermal resistance (or thermal conductivity) can be measured.

[0019] Individual electrical properties, including static and / or dynamic electrical properties of the power semiconductor circuit or the individual power semiconductors within the circuit, can be recorded and stored. These properties include, in particular, a power dissipation factor that assigns to at least one electrical operating point (defined by the current and / or voltage in or across the power path of the semiconductor switch or power semiconductor circuit) the heat dissipation generated at that operating point within the power semiconductor circuit. The operating point is 202401590

[0020] 5. In particular, the operating point is defined by a maximum, standard, or test current. Alternatively or in combination with this, the operating point may be defined by the level of a supply voltage. The electrical property is, in particular, a thermal electrical property, such as thermal power, which relates to power generated during the operation of the power semiconductor circuit at a specific electrical operating point or at a specific electrical power absorbed by the circuit, or which exists in the circuit at specific torque or power requirements, which may be configured as a traction inverter of a vehicle.

[0021] Electrical properties that can be considered include, for example, the active resistance (in steady state) and the voltage drop in the power path (source-drain or emitter-collector) in the active state. Alternatively, or in combination with these, a dynamic property can be considered, such as the slew rate (rising and / or falling edge), the magnitude of a gate capacitance, the magnitude of a Miller capacitance, or other parasitic elements that influence the switching behavior. At least one of these properties is individually defined for each power semiconductor or power semiconductor circuit.

[0022] As a thermal conductivity property, the temperature and / or temperature rise of the power semiconductor circuit, particularly of semiconductor switches, can be measured. This is measured under predefined operating conditions, for example, as the temperature or temperature rise resulting from a predefined energy or power input for a predefined duration, where the energy or power is electrical in nature and has been supplied to the circuit or semiconductor. Furthermore, the predefined operating conditions can include a specific pulse pattern used to drive the circuit or semiconductor. Thus, the temperature of the circuit or semiconductor switches, or its rise, is characteristic of a thermal conductivity property of the circuit or semiconductor switches.The operating conditions may further specify a given flow rate and / or a given temperature of the cooling medium flowing through the heat sink (where energy or power is supplied). In other words, the temperature or its increase may refer to a specific test operating mode, so that the temperature or its increase is indicative of the individual thermal conductivity. 202401590.

[0023] 6

[0024] In particular, the operating conditions can be defined by an end-of-line test of the circuit. The operating conditions correspond to a predetermined electrical load. The predetermined electrical load is specifically defined by the operating conditions.

[0025] Furthermore, the thermal conductivity can directly or indirectly characterize the thermal resistance in the semiconductor area of ​​a semiconductor switch, the circuit, the (optional) housing, the semiconductor switch's mounting element, the substrate, and / or the heat sink. For example, individual structural properties of the working area, the housing, the mounting element, and / or the substrate, and possibly also the heat sink connection, characterize the individual thermal conductivity. Such circuit properties include, for example, the second layer thickness, contact pressure, density, size, and / or location of air connections, and similar characteristics. This thermal conductivity is recorded and stored.

[0026] Preferably, the individual properties are stored as values ​​that directly reflect the measurement results obtained during the acquisition step. This applies to the individual electrical properties as well as the individual thermal conductivity properties. In particular, the individual properties can be stored as values ​​that refer to the same physical quantity that was measured. Alternatively, a conversion or evaluation can be performed between acquisition and storage. In this case, the individual properties can be stored as values ​​that represent parameters of a thermal model. These parameters are derived from the measurement results obtained during the acquisition step through conversion and / or evaluation. Furthermore, the measurement results can be converted, particularly to a different quantity than the one measured during the acquisition step.In other words, the measurement results obtained at the end of production (by recording) can be stored directly, or derived values ​​can be stored that characterize the relevant property.

[0027] The acquisition step can, for example, involve individually measuring the temperature or temperature change of the respective power semiconductor circuit. The temperature itself can be measured, or the measurement can be performed by deriving the temperature from a temperature-dependent electrical parameter of the 202401590.

[0028] 7

[0029] For example, a power semiconductor circuit can have a voltage drop across the electrodes of a semiconductor switch within the circuit. Thus, temperature or temperature changes can represent a parameter that characterizes the individual property (electrical property and / or thermal conductivity). Furthermore, the acquisition process can involve imaging a structural section of the power semiconductor circuit. In particular, the mounting element can be imaged as a structural section. Any defects present, which are shown in the acquired image, are characteristic of the thermal conductivity. In particular, defects in the form of influences, especially voids or air inclusions, characterize the individual thermal conductivity of the respective mounting element of the power semiconductor circuit.Characteristics of heat conduction properties can include the location, size (area), and distance of defects from each other, from the edge, or from the center.

[0030] As mentioned, the individual properties stored in memory are also used in controlling the respective power semiconductor circuit, particularly in derating the circuit. Preferably, these properties are used as model parameters of an individual thermal model of the individual power semiconductor circuit. The electrical properties, in particular, characterize the heat generation characteristics of the component and can therefore be considered conversion-specific thermal properties.

[0031] The power semiconductor circuit in question can be used in a product, particularly a power electronics product. The procedure described here relates specifically to the control of this power electronics product and / or the product itself. The control can be implemented as a control device.

[0032] A method for operating a product comprising at least one power semiconductor circuit as described herein involves the application of the procedure described here. The product may be designed as a power electronics device, in particular as a power inverter, power DC-DC converter, or power factor correction filter. The operation of such a product involves operating the at least one power semiconductor circuit taking into account its individual characteristics. These are, 202401590

[0033] 8 as described herein, stored in a memory. The operation specifically provides for temperature monitoring, which is carried out using a temperature model that takes into account at least one of the described individual properties. In other words, the monitoring preferably incorporates a temperature model that is specific to the power semiconductor circuit used, whereby the model's parameters represent at least one of the aforementioned individual properties. This ensures that the individual electrical and / or thermal properties are considered during product operation. This facilitates better utilization of the individual properties of each circuit by using the properties recorded at the end of manufacturing (and not just the properties of the circuit breaker types used, i.e., the type-specific properties) for temperature monitoring.

[0034] As an example, the product can be configured as a power traction inverter for a vehicle. It can also be configured in multiple ways. At least one power semiconductor circuit can be used per phase, which can be connected in parallel. Each power semiconductor circuit can form a half-bridge, thus forming a multiphase bridge circuit together with the other semiconductor circuits. The properties are determined and stored individually for each semiconductor circuit, for each phase, or for the entire product (and are also applied in the relevant thermal model during control).

[0035] The procedure described here can be implemented in the form of a control device. This device is configured to control power semiconductor circuits as described herein. The individual properties are recorded and stored as described. In particular, the properties are stored in a memory. The memory can be part of the control device. Other embodiments provide for the memory to be located outside the control device, and the control device therefore has a data interface configured to retrieve the individual properties from the memory. The memory can, in particular, be part of a control module that houses the control device. In this case, a corresponding connection exists between the control device within the control module and the memory within the control module.Other embodiments provide for the memory to be located outside the control device, outside the control module, or outside the product. In this case, see 202401590.

[0036] 9

[0037] In this case, the control device, the control module in which the control device is located, or the product in which the control device is located has a communication interface for retrieving individual properties from a memory, which is, for example, configured as cloud storage. Each power semiconductor circuit is preferably equipped with a unique identifier. When retrieving properties from the memory, this identifier can be transmitted to the memory, so that the memory outputs the relevant property associated with the identifier. If the memory and the control device or power semiconductor circuit are in the same device, this arrangement can provide a unique assignment, making the transmission of an identifier unnecessary. The control device is configured to apply the individual properties when controlling the at least one power semiconductor circuit.In particular, the control device can include a thermal model that is designed or parameterized according to the individual properties of the at least one power semiconductor circuit. The thermal model can be part of a temperature monitoring system for the control device. Furthermore, the individual properties can be used within the framework of a control system implemented by the control device, in particular a control system for the operation of an electric machine, such as vector control.

[0038] A product (as described herein) can be provided with individual power semiconductor circuits and a control module as described herein. The control module includes the control device as described herein. The control device is connected to the power semiconductor circuits for control purposes. The memory is preferably located in the control module. The memory is connected to the control device. The individual properties of the individual power semiconductor circuits are stored in the memory. The control device preferably includes thermal models of the power semiconductor circuits, which are parameterized according to the associated individual properties. The control device can provide temperature monitoring, which uses the models for temperature determination or estimation.

[0039] Figure 1 serves to further illustrate embodiments of the method and devices described herein. 202401590

[0040] 10

[0041] Figure 1 shows below an individual instance EX42 of a power semiconductor circuit EX. Like another instance EX43, the EX42 power semiconductor circuit has a heat sink KK on which a substrate S is mounted. The substrate S serves as a support for two semiconductor switches H1 and H2, each connected to the substrate S via one of the mounting elements B1 and B2. The substrate S serves to electrically connect the semiconductor switches H1 and H2 and, for this purpose, has conductive traces or other conductive structures, which are not shown for the sake of simplicity. The mounting elements B1 and B2 are, in particular, symbolically represented sintered layers that connect the undersides of the respective semiconductor switches H1 and H2 to corresponding surface sections of the substrate S.A connecting element can also be provided between the substrate S and the heat sink KK, the thermal properties of which can be individually defined for the EX 42 unit. A connection V, symbolically represented as a bonding connection, connects to a corresponding (conductive) surface of the substrate S, to which the underside of the semiconductor switch H2 is also connected. A half-bridge circuit can be formed by connecting elements H1 and H2 in series via the connection V. The substrate S with the semiconductor switches H1 and H2 mounted on it can be referred to as a power module. More than two semiconductor switches can be provided on the substrate S. Several substrates S can be provided on the heat sink KK.

[0042] The individual thermal conductivity and electrical properties of the depicted EX42 power semiconductor circuit EX are recorded after its manufacture, or at the end of the manufacturing process, and stored in memory M. In the illustrated example, the memory is mounted on the heat sink KK. However, it can also be located on the substrate S. The memory M preferably stores the individual properties of the EX42 instance. By its arrangement, memory M is assigned to this EX42 instance. If multiple instances are assigned to memory M, the identifiers of the individual instance are stored together with their associated individual properties (in such a way that this assignment can be retrieved).

[0043] An alternative version of memory M is represented by the reference symbol M'. This memory stores individual properties of several instances, designated 42 and 43. For each instance 202401590

[0044] 11

[0045] 42, 43 represent a thermal resistance RT, RT and an ancillary resistance RON, RON'. Instead of the ancillary resistance, a power dissipation factor can be represented for each unit.

[0046] Memory M' is part of an exemplary product P, which, in addition to instance EX42, also includes instance EX43, each with a performance characteristic of circuit EX. Product P has a control device C, which is connected to both instances EX42 and EX43. This is indicated by the arrows to the right of the control device C. The properties marked 42 in memory M' are the individual properties of instance EX42. The properties marked 43 in memory M' are the individual properties of instance EX43. The control device C has an interface I, which is configured for communication with memory M'. In the illustrated example, memory M' is located outside the control device C, but within product P.It can also be provided that the memory is located outside of the product P, with a data connection, in particular via the internet, establishing the connection between memory M' and interface I of the control device C. This data exchange is represented by the horizontal double arrow, which represents the transmission of identification markers (42, 43) from the control device C to memory M' and the subsequent transmission of the relevant properties RT, RON from memory M' to interface I. The vertical double arrow indicates that the instance EX42 has individual properties stored in memory M' (in case memory M is not present), and that these individual properties are available for the operation of the instance EX42 shown below.

Claims

202401590 12 Patent claims 1. Method for recording and storing individual properties of power semiconductor circuits (EX) comprising the following steps: Capturing at least one individual electrical property (RON) and at least one individual thermal conductivity property (RT) as individual properties of the individual power semiconductor circuits (EX42, EX43) after manufacturing and before installation of the power semiconductor circuits into a product (P); The properties are stored individually for each instance (EX42, EX43) of the power semiconductor circuits (EX) in a memory (M), which can be retrieved during the operation of the power semiconductor circuits for a control (C) of the respective power semiconductor circuit.

2. Method according to claim 1, wherein the individual electrical properties are a power loss factor, an ON resistance (RON), a slope, a gate capacitance, and / or a voltage drop on the power path in the ON state of semiconductor switches of the power semiconductor circuits, which are detected and stored.

3. Method according to claim 1 or 2, wherein a temperature or temperature increase of semiconductor switches (H1, H2) of the power semiconductor circuits (EX) resulting from a predetermined electrical load is detected and stored as a thermal conductivity property, and / or wherein a thermal resistance (RT) in the semiconductor area of ​​a semiconductor switch (H1, H2), the housing of the semiconductor switch (H1, H2), in a mounting element (B1, B2) of the semiconductor switch (H1, H2), in a substrate (S) on which the semiconductor switch (H1, H2) is mounted, and / or a heat sink (KK) on which the semiconductor switch (H1, H2) is arranged, is detected and stored as at least one individual thermal conductivity property.

4. A method according to claim 1, 2 or 3, wherein the individual properties are stored in the form of values ​​that directly reflect measurement results themselves, which are measured in the acquisition step, or wherein the individual properties are stored in the form of values ​​that reflect parameters of a thermal model, wherein the Parameters are derived from measurement results, which are measured during the acquisition step. 202401590 13 5. Method according to one of the preceding claims, wherein the detection step comprises the individual measurement of a temperature or temperature change of the power semiconductor circuits under given conditions and / or an imaging representation of a fastening element (B1 , B2) of a semiconductor switch (H1 , H2) of the power semiconductor circuits (EX).

6. Method according to claim 5, wherein the detection step provides for individually and image-based representation of the fastening element (B1 , B2) of the semiconductor switch (H1 , H2) of the power semiconductor circuits (EX), wherein the thermal conductivity of the fastening element (B1 , B2) is stored as an individual thermal conductivity property, which is characteristic of defects that are detected in the image-based representation of the fastening element (B1 , B2).

7. Method for operating a product configured as a power converter or power DC-DC converter or power factor correction filter, wherein the product has at least one power semiconductor circuit (EX42, EX43), wherein the method provides to operate the at least one power semiconductor circuit (EX42, EX43) taking into account the individual properties which are stored in a memory (M) according to the method according to one of the preceding claims.

8. Control device (C) configured for controlling power semiconductor circuits (EX), the individual properties of which are stored in a memory (M) according to the method of one of the preceding claims, wherein the control device (C) has a data interface which is configured to retrieve the individual properties and to use them when controlling the power semiconductor circuits (EX).

9. Product (P) with individual power semiconductor circuits (EX42, EX43) and a control module comprising the control device (C) according to claim 8, wherein the control device (C) is connected to the power semiconductor circuits (EX42, EX43) in a controlling manner, the memory (M) is arranged in the control module and is connected to the control device (C), wherein the individual properties of the individual power semiconductor circuits (EX42, EX43) are stored in the memory (M). 202401590 14 10. Product (P) according to claim 9, wherein the product is configured as a power converter or as a power DC-DC converter or as a power factor correction filter.

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