Power device parameter adjustment

Abstract

The present disclosure provides "power device parameter adjustment." A computer includes: a processor; and a memory. The memory stores instructions executable by the processor to determine, based on measurements taken in a vehicle, that a parameter of a power device is outside a predetermined range; and to actuate a component in the vehicle to heat the power device.

Description

Technical Field

[0001] The present invention relates to the field of electric vehicles, and more particularly to power devices in electric vehicles. Background Art

[0002] Electric vehicles, hybrid electric vehicles, and plug-in hybrid electric vehicles use power devices such as IGBTs (insulated gate bipolar transistors) and power MOSFETs (metal oxide semiconductor field effect transistors) to drive motors in powertrains and applications such as charging units and power conversion units. Over time, as power devices age, electrical parameters such as threshold voltage and on-resistance can change. These changes in electrical parameters can degrade vehicle performance. Furthermore, replacing power devices is expensive and can require the hassle of taking the vehicle to a service station. Detecting aging power devices and adjusting their parameters is a problem. Summary of the Invention

[0003] A computer includes a processor programmed to determine, based on measurements performed in a vehicle, that a parameter of a power device is outside a predetermined range; and actuate a component in the vehicle to heat the power device.

[0004] The processor may also be programmed to determine that the power device is heated within a predetermined time; perform a second measurement on the power device; determine, based on the second measurement, that a parameter of the power device is within a target range; and store the state of the power device. The parameter of the power device that is outside the predetermined range may be one of a threshold voltage and an on-resistance.

[0005] The processor can also be programmed to determine a target time for heating the power device based on the measurement. The processor can also be programmed to monitor an adjusted time for the power device to be heated by the vehicle component; and actuate the vehicle component to stop heating the power device when the adjusted time for the power device to be heated by the component is greater than or equal to the target time.

[0006] The instructions to the vehicle component may include instructions executable to: activate a heating unit in the vehicle; and pump coolant along a coolant path to transfer heat from the heating unit to the power device.

[0007] The processor may also be programmed to actuate the vehicle component to perform measurements including: varying a gate-source voltage of the power device over time; monitoring current through the power device; and measuring the gate-source voltage when the current through the power device reaches a predetermined current.

[0008] Determining that the power device is operating outside of a predetermined range may include programming to determine that a gate-to-source voltage when a current through the power device reaches a predetermined current is outside of a predetermined range.

[0009] The processor may also be programmed to actuate the vehicle component to request authorization to adjust the power device via the human-machine interface; and transmit a second instruction to the component based in part on receiving the authorization to adjust the power device. Requesting authorization to adjust the power device may include instructing the human-machine interface to display a target time for heating the power device at the human-machine interface.

[0010] A method includes determining, based on a measurement performed in a vehicle, that a parameter of a power device is outside a predetermined range; and actuating a component in the vehicle to heat the power device. The method may also include determining that the power device is heated within a predetermined time; performing a second measurement on the power device; determining, based on the second measurement, that the parameter of the power device is within a target range; and storing a state of the power device.

[0011] The method may also include determining a target time for heating the power device based on the measurement. The method may also include monitoring a settling time for the power device to be heated by the vehicle component; and actuating the vehicle component to stop heating the power device when the settling time for the power device to be heated by the component is greater than or equal to the target time. The method may also include activating a heating unit in the vehicle; and pumping coolant along the coolant path to transfer heat from the heating unit to the power device.

[0012] The method may further include actuating a vehicle component to perform a measurement, including: varying a gate-source voltage of a power device over time; monitoring a current through the power device; and measuring the gate-source voltage when the current through the power device reaches a predetermined current. Determining that a parameter of the power device is outside a predetermined range may include determining that the gate-source voltage is outside the predetermined range when the current through the power device reaches the predetermined current. The method may further include requesting authorization to adjust the power device via a human-machine interface; and transmitting a second instruction to the component based in part on receiving the authorization to adjust the power device.

[0013] Also disclosed is a computer comprising a processor programmed to perform any of the above method steps. Also disclosed is a vehicle comprising a computer. Also disclosed is a computer program product comprising a computer-readable medium storing instructions executable by a processor to perform any of the above method steps.

[0014] A system including a vehicle includes: a power device; a measurement device for measuring an output of the power device; and a computer. The computer includes a processor programmed to: determine, based on a measurement performed in the vehicle by the measurement device, that a parameter of the power device is outside a predetermined range; and actuate a component in the vehicle to heat the power device. The processor may also be programmed to determine that the power device is heated within a predetermined time; perform a second measurement on the power device; determine, based on the second measurement, that the parameter of the power device is within a target range; and store a state of the power device. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a diagram of a system including an exemplary vehicle system for measuring and adjusting electrical parameters of power devices.

[0016] Figure 2 is a diagram of a portion of an exemplary vehicle system for measuring electrical parameters of power devices included in an exemplary inverter.

[0017] Figure 3 is a diagram of an exemplary inverter including six power devices.

[0018] Figure 4 is a diagram of an exemplary process for measuring power device parameters.

[0019] Figure 5A is a diagram of a first portion of an exemplary process for adjusting parameters of a power device.

[0020] Figure 5B yes Figure 5A FIG. 1 is a diagram of the second part of the exemplary process.

[0021] Figure 6A is a diagram of an exemplary vehicle configured for measuring and adjusting electrical parameters of power devices, the exemplary vehicle including a valve for controlling coolant flow switched to a position for normal operation.

[0022] Figure 6B yes Figure 6A FIG. 1 is a diagram of an exemplary vehicle in which a valve is switched to a position for adjusting an electrical parameter of a power device. DETAILED DESCRIPTION

[0023] Figure 1 An example system 5 is shown that includes a vehicle 10 , a server 12 , and a network 14 . The system 5 may also include a power source 52 .

[0024] Vehicle 10 includes inverter 20, which includes one or more power devices 22. As described herein, vehicle 10 can measure in a measurement mode and adjust in an adjustment mode parameters of power devices 22. System 5 can also include power source 52, which can be an electrical outlet.

[0025] Vehicle 10 includes a computer 24. Vehicle 10 may also include an inverter 20, a measurement unit 26, a motor 28, an engine 29, a coolant tank 30, a pump 34, a heating unit 38, a charging unit 44, a battery 46, a power unit 48, and a human-machine interface (HMI) 50 (collectively, components), each of which may be communicatively coupled to computer 24, for example, in a manner further described below. In some cases, vehicle 10 may not include one or more of these components. For example, as described below, in some cases, vehicle 10 may not include coolant tank 30.

[0026] To cool the power devices 22 during normal mode and to heat the power devices 22 in the inverter 20 during regulation mode, the vehicle 10 circulates coolant through the coolant path 54. Normal mode may also be referred to herein as normal operation. The coolant path 54 includes the coolant tank 30, the first pipe 32, the pump 34, the second pipe 36, the heating unit 38, the third pipe 40, the inverter 20, and the fourth pipe 42.

[0027] The coolant path 54 is merely an example. Elements such as the pump 34, the heating unit 38, and the inverter 20 may be arranged in a different order than in this example. Furthermore, in some cases, the coolant path 54 may not include all elements. For example, the coolant tank 30 may not be required for the coolant path 54.

[0028] The coolant path 54 is typically provided to remove heat from the power devices 22 in normal mode. Furthermore, as further described below, the coolant path 54 is arranged in a manner that transfers heat from the heating unit 38 to the power devices 22 in the inverter 22 during regulation mode. In the event that the coolant path 54 does not include the coolant tank 30, the coolant contained in the remainder of the coolant path 54 transfers heat to cool the power devices 22 in normal mode and to heat the power devices 22 in regulation mode.

[0029] The inverter 20 includes one or more power devices 22 and is drivingly coupled to (i.e., can drive) a motor 28 in a normal mode. The inverter 20 includes a computer and is communicatively coupled to a computer 24. As described in further detail below, the inverter 20 can provide a measurement unit 26 with access to electrical nodes and signals within the inverter 20 in a measurement mode. In some cases, the inverter 20 can operate normally (i.e., as in a normal mode) during the measurement mode. In these cases, the measurement mode indicates that the electrical nodes and other signals within the inverter 20 are available to the measurement unit 26, and the measurement unit 26 performs measurements while the inverter 20 operates normally. The measurement unit 26 can perform measurements of electrical parameters of the power devices 22. The power devices 22 can be devices such as power metal oxide semiconductor field effect transistors (MOSFETs) or insulated gate bipolar transistors (IGBTs). The power devices 22 have electrical parameters, including a threshold voltage. The electrical parameters are digital factors or other measurable factors that form a set describing the operating conditions of the corresponding power devices 22. The threshold voltage is the voltage between the control input and the first conductive terminal of power device 22 at which power device 22 conducts a current at or above a predetermined current. In the case of a power MOSFET, the control input is called the gate terminal, and the first conductive terminal to which the threshold voltage is referenced is called the source terminal. In the case of an IGBT, the control input is called the gate terminal, and the first conductive terminal to which the threshold voltage is referenced is called the emitter terminal. A power MOSFET has a second conductive terminal called the drain terminal. An IGBT has a second conductive terminal called the collector terminal.

[0030] The following procedures for measuring and adjusting power device 22 relate to measuring and adjusting the electrical parameters of a power MOSFET. These procedures can also be used to measure and adjust the electrical parameters of an IGBT.

[0031] The computer 24 includes a processor and memory. The memory includes one or more types of computer-readable media and stores instructions executable by the processor for performing various operations, including the operations disclosed herein. In addition, the computer 24 may include and / or may be communicatively coupled to one or more other computers, including vehicle components such as the inverter 20, the measurement unit 26, the motor 28, the engine 29, the coolant tank 30, the pump 34, the heating unit 38, the charging unit 44, the battery 46, the power unit 48, and the HMI 50, which may also include corresponding processors and memory. Communication (i.e., communicatively coupling) may be via a controller area network (CAN) bus or a local interconnect network (LIN) bus, for example, using wired technology or such. This can be achieved through a wired and / or wireless vehicle local area network (LAN) based on wireless technologies such as .

[0032] The measurement unit 26 is electrically coupled to the inverter 20 and includes one or more sensors for detecting electrical parameters of the power devices 22 in the inverter 20. The measurement unit 26 may further include one or more excitation units, such as power supplies or current sources, that can be used to apply a steady-state or time-varying voltage or current to a node on the power device 22 or other electrical nodes within the inverter 20. The measurement unit 26 includes a computer and is communicatively coupled to the computer 24. As described in further detail below, the measurement unit 26 can be programmed in a measurement mode to sense electrical parameters of one or more of the power devices 22 and provide data specifying the electrical parameters of the one or more power devices to the computer 24. In some cases, the measurement unit 26 can additionally or alternatively be programmed to apply a voltage or current to one or more nodes on the power devices 22 within the inverter 20.

[0033] The motor 28 is an electric motor as is known for use in powertrain applications in the vehicle 10. The motor 28 is electrically coupled to and driven by the inverter 20.

[0034] Vehicle 10 may also include an engine 29. Engine 29 may be a diesel or gasoline combustion engine. Computer 24 may be programmed to activate engine 29 during the tuning mode to charge battery 46. In this case, engine 29 may drive charging unit 44, which converts mechanical energy from engine 29 into electrical energy.

[0035] The coolant tank 30 is a tank for storing coolant. When the coolant circulates, the coolant enters the coolant tank 30 through the fourth pipe 42 connected between the inverter 20 and the coolant tank 30. The coolant leaves the coolant tank 30 through the first pipe 32 connected between the coolant tank 30 and the pump 34. As described above, in some cases, the vehicle 10 does not include the coolant tank 30.

[0036] The pump 34 can pump the coolant around the coolant path 54. The pump 34 includes a computer communicatively coupled to the computer 24 and an actuator for pumping the coolant. The computer in the pump 34 is programmed to control the actuator based on instructions from the computer 24.

[0037] The heating unit 38 includes a computer and a heating element 39, such as a resistive heating element, and may also include one or more switches for turning on the heating element 39. The computer in the heating unit 38 is communicatively coupled to the computer 24. The computer in the heating unit 38 is programmed to receive instructions from the computer 24 and, based on the instructions, turn the heating element 39 on and off. In normal mode, the heating element 39 will be turned off because the coolant is used to cool the power device 22 in this mode. As described in further detail below, during the adjustment mode, the heating element 39 in the heating unit 38 can be turned on to heat the power device 22, thereby adjusting the electrical parameters of the power device 22.

[0038] The charging unit 44 generates electrical energy from mechanical energy from the engine 29. During the regulation mode, the engine 29 may be activated from time to time to maintain the charge in the battery 46.

[0039] Battery 46 may be, for example, a lithium-ion or nickel-metal hydride battery, a supercapacitor, or a fuel cell. This list is not intended to be limiting. Battery 46 may be any type of charge storage device. Battery 46 may be connected to charging unit 44 so that it can be charged. Additionally or alternatively, battery 46 may be further charged by plugging vehicle 10 into an external power source, such as power source 52.

[0040] The vehicle 10 may include a power unit 48. The power unit 48 may receive power from the battery 46. The power unit 48 may also convert the voltage level of the power from the battery 46 to one or more voltage levels compatible with power consumers in the vehicle 10, such as the pump 34, the heating unit 38, etc.

[0041] The vehicle 10 also includes a human-machine interface (HMI) 50. The HMI 50 can allow passengers of the first vehicle 10 to interact with the computer 24 and components of the vehicle (such as the measurement unit 26, the inverter 20, the pump 34, the heating unit 38, etc.). The HMI 50 can include any of a variety of computing devices (including a processor and memory) and communication capabilities. The HMI 50 can be a portable computer, a tablet computer, a mobile phone (e.g., a smartphone), etc. that includes the ability to communicate wirelessly using IEEE 802.11, Bluetooth, and / or cellular communication protocols. The HMI 50 can also include an interactive voice response (IVR) and / or a graphical user interface (GUI), including a touch screen, etc. The HMI 50 can communicate with a network extending outside the vehicle 10 and can communicate directly with an external server, for example, using Bluetooth, etc.

[0042] The HMI 50 may communicate a request to the user, such as a request for the user to authorize an adjustment mode, to adjust parameters of the power device 22. The HMI 50 may receive instructions from the user, such as instructions to authorize the adjustment mode, interrupt the adjustment mode, delay execution of the adjustment mode, etc., and transmit the instructions to the computer 24.

[0043] The system 5 may include a power source 52. The power source 52 may be an electrical outlet configured to provide power to the vehicle 10 to charge the battery 46. The power source 52 may also be used to provide power to the heating unit 38 when the vehicle 10 is operated in the conditioning mode.

[0044] The server 12 includes a processor and a memory storing instructions executable by the processor. The server 12 is communicatively connected to the vehicle 10 via a network 12 .

[0045] The server 12 is programmed to receive and store data related to the electrical parameters of the power devices 22 and adjustments made to the power devices 22. For example, the server 12 can store and maintain historical threshold voltage and / or on-resistance data for each power device 22. The server 12 can also store and maintain data indicating details of adjustment patterns, such as the duration and temperature at which adjustments were made to the power devices 22, and the resulting changes in threshold voltage and / or on-resistance. The server 12 can be programmed to correlate data from the vehicle 10 with other vehicles to form, for example, statistics indicating how long it takes for the threshold or on-resistance to be adjusted by a fixed amount (e.g., 1 volt) for the power devices 22 when heated to a specified temperature.

[0046] The network 14 is one or more mechanisms by which the vehicle 10 and the server 12 communicate with each other and can be one or more of a variety of wired or wireless communication mechanisms, including wired (e.g., cable and fiber optic) and / or wireless (e.g., cellular, wireless, satellite, microwave, and radio frequency) communication mechanisms and any desired network topology (or topology when multiple communication mechanisms are used). Exemplary communication networks include wireless communication networks that provide data communication services (e.g., using cellular, One or more of IEEE 802.11, etc.), local area networks (LANs) and / or wide area networks (WANs), including the Internet.

[0047] Types of wireless communications can include cellular, IEEE 802.11 (usually ), dedicated short range communications (DSRC), two-way satellite (e.g., emergency services), one-way satellite (e.g., receiving digital audio radio broadcasts), AM / FM radio, etc.

[0048] Figure 2A system or subsystem of an exemplary vehicle 10 is shown that is configured to measure parameters of power devices 22 included in inverter 20. Computer 24 is programmed to execute a measurement mode. Measurement mode is an operating mode in which computer 24 is programmed and measurement unit 26 is coupled to nodes and signals to measure one or more electrical parameters of power devices 22. Computer 24 is communicatively coupled to inverter 20 via communication channel CTL1. In measurement mode, computer 24 can send one or more instructions to inverter 20 to configure one of power devices 22 for measurement. As described in further detail below, configuring to measure power device 22 can include providing measurement unit 26 with access to one or more electrical nodes in inverter 20.

[0049] The computer 24 also communicates with the node V via the communication channel CTL2. MEAS to be communicatively coupled to the measurement unit 26 .

[0050] The inverter 20 includes one or more power devices 22 as described above. The inverter 20 receives commands as input from the computer 24 via the communication channel CTL1. In addition, the inverter 20 is coupled to the power output and ground connection of the power source 62. The inverter 20 can output one or more currents I1-I3 to the load 60 at nodes L1-L3, respectively.

[0051] The inverter 20 can be switched to a state that provides access to one or more nodes of the inverter 20 to the measurement unit 26. The inverter 20 can include an electrical switch that switches a node, such as a gate node or a source node of the power device 22, to a node coupled to the measurement unit 26. The computer 24 can actuate the switch to provide access to the selected electrical node to the measurement unit 26. The one or more nodes may include one or more of the gate nodes G1-G6 of the power device 22, and may also include nodes L1-L3. In addition, the inverter 20 can provide one or more signals IL1-IL3 from corresponding current sensors CS1-CS3. The signals IL1-IL3 are signals indicating currents I1-I3, respectively.

[0052] Measurement unit 26 is communicatively coupled to computer 24 via communication channel CTL2, such that measurement unit 26 can receive one or more instructions from computer 24. Measurement unit 26 can also receive signals IL1-IL3 from respective current sensors CS1-CS3 as inputs. Measurement unit 26 can also receive gate nodes G1-G6 of power device 22 as inputs. In addition, measurement unit 26 can receive power output and a ground connection from power supply 62 as inputs.

[0053] Based on inputs received from inverter 20 and power source 62, measurement unit 26 is programmed to determine a threshold voltage of one or more of power devices 22. Additionally or alternatively, measurement unit 26 may be programmed to determine an on-resistance of one or more of power devices 22. Measurement unit 26 is further programmed to output a signal V that represents the threshold voltage of one or more power devices 22, respectively. MEAS Alternatively, when measuring the on-resistance of the power device 22, V MEAS It can represent the on-resistance of the corresponding power device 22.

[0054] A power source 62 is coupled to provide a power output and a ground connection to the inverter 20 and the measurement unit 26. In some configurations, the power source 62 may be a battery, such as the battery 46. In other configurations, the power source 62 may be a power unit, such as the power unit 48.

[0055] The load 60 typically includes a motor, such as the motor 28. Additionally or alternatively, an electrical circuit including resistors, capacitors, inductors, and switching devices such as transistors may be included in the load 60.

[0056] Figure 3 An exemplary inverter 20 is shown coupled to a load 60 and a power source 62. The inverter 20 includes six power devices 22-1, 22-2, 22-3, 22-4, 22-5, and 22-6 (collectively referred to as power devices 22). The six power devices 22-1, 22-2, 22-3, 22-4, 22-5, and 22-6 include gate terminals G1, G2, G3, G4, G5, and G6, drain terminals D1, D2, D3, D4, D5, and D6, and source terminals S1, S2, S3, S4, S5, and S6, respectively.

[0057] Power devices 22-1 and 22-4 are arranged in series between power node VP and ground node GND. Source terminal S1 of power device 22-1 is coupled to drain terminal D4 of power device 22-4 via node L1. Power devices 22-2 and 22-5 are similarly arranged in series between power node VP and ground node GND, with source terminal S2 of power device 22-2 coupled to drain terminal D5 of power device 22-5 via node L2. Power devices 22-3 and 22-6 are also arranged in series between power node VP and ground node GND, with source terminal S3 of power device 22-3 coupled to drain terminal D6 of power device 22-6 via node L3.

[0058] The inverter 20 includes three current sensors CS1, CS2, and CS3. The current sensors CS1, CS2, and CS3 measure the currents passing through nodes L1, L2, and L3, respectively, and output signals IL1, IL2, and IL3, respectively.

[0059] During the measurement mode, the measurement unit 26 can measure the voltage between the gate terminal and the source terminal of one of the power devices 22 while monitoring the current through the power device 22 to determine the gate-source voltage at which the current reaches a predetermined current. This measurement can be performed while the power device 22 is turned on. That is, the measurement can be performed during the period when the gate-source voltage rises from a voltage lower than the threshold voltage to the threshold voltage.

[0060] For example, to measure power device 22-4, measurement unit 26 can measure the voltage between gate terminal G4 and source terminal S1 (coupled to GND) while monitoring current I1 on node L1. Computer 24 is programmed to turn off power device 22-1 during this measurement, or to perform the measurement when it is known that power device 22-1 is off. Current I1 is monitored by current sensor CS1, which provides signal IL1 to measurement unit 26.

[0061] While the power device 22-4 is on, the gate-source voltage between the gate terminal G4 and the source terminal S1 increases from a voltage below the threshold voltage. As the gate-source voltage approaches the threshold voltage, the current I1 begins to increase. When the current I1 reaches a predetermined limit, the gate-source voltage between the gate terminal G4 and the source terminal S1 is identified as the threshold voltage of the power device 22-4.

[0062] The threshold voltage of each of the other power devices 22 - 1 , 22 - 2 , 22 - 3 , 22 - 5 , and 22 - 6 can be measured in a comparable manner. The voltages and currents to be measured are shown in Table 1 below.

[0063] Device Gate terminal source terminal Current Current sensor output condition 22-1 G1 L1 I1 IL1 G4 Off 22-2 G2 L2 I2 IL2 G5 level 22-3 G3 L3 I3 IL3 G6 level 22-4 G4 GND I1 IL1 G1 level 22-5 G5 GND I2 IL2 G2 level 22-6 G6 GND I3 IL3 G3 level

[0064] Table 1

[0065] In addition to or instead of measuring the threshold voltage of the corresponding power device 22, the measurement unit 26 may measure the on-resistance of the corresponding power device 22. In this case, the measurement unit 26 may, for example, apply a voltage from the gate to the source of the power device 22, measure the voltage from the drain to the source of the power device 22, and also measure the current from the drain to the source through the power device 22.

[0066] For example, to measure the on-resistance of power device 22-4, measurement unit 26 may apply (or measure) a voltage from G4 to GND. Measurement unit 26 may also measure a voltage from L1 to GND. Measurement unit 26 may also receive signal IL1 representing current I1. On-resistance may be calculated as on-resistance = (voltage from L1 to GND) / I1.

[0067] Figure 4is a flow chart of an exemplary process 400 for measuring electrical parameters of power device 22. Process 400 begins in block 405.

[0068] In block 405, the vehicle 10 is turned on. The computer 24 may be activated upon turning on the vehicle 10. For example, this may mean that power is applied to the computer 24 or the computer 24 is awakened from a sleep mode or otherwise set to an active mode to initiate the process 400 for measuring the thresholds of the power devices 22. Once the vehicle 10 is turned on and the computer 24 is activated, the process 400 continues in block 410.

[0069] In block 410, the computer 24 is programmed to determine whether the inverter 20 is operating. That is, the computer 24 may receive data from sensors associated with the inverter 20 indicating that the inverter 20 is actively driving the motor 28 or is energized under certain conditions to switch the power devices 22. If the inverter 20 is not operating, the process 400 continues in block 415. If the computer 24 determines that the inverter 20 is operating, the process 400 continues in block 420.

[0070] In block 415 (which may follow block 410), the computer 24 determines whether the vehicle 10 is still on. For example, the computer 24 may monitor the ignition input of the vehicle 10 to determine that the ignition is held in the "on" position. If the vehicle 10 is no longer on, the process 400 ends. If the vehicle 10 continues to operate, the process 400 returns to block 410 to monitor the operation of the inverter 20.

[0071] In box 420 (which may be after box 410), the computer 24 monitors the operating time of the inverter 20 since the last measurement. The operating time since the last measurement is defined herein as the operating time of the inverter 20 since the last measurement of the power device parameter. Once it is determined that the inverter 20 is operating as described in box 410, the computer 24 enables a counter that monitors the operating time since the last measurement. In box 420 (which may be run simultaneously with other boxes in process 400), the computer 24 continues to monitor the time that the inverter 20 is operating and counts it. The operating time since the last measurement of the inverter 20 can be used to estimate the number of times the corresponding power device 22 in the inverter 20 has switched since the last measurement. Once the timer is enabled, process 400 continues in box 425.

[0072] The previous paragraph describes monitoring the operating time of the inverter 20. In some cases, the power device 22 may be included in other components, such as the charging unit 44. The computer 24 may monitor the operating time since the last measurement of any vehicle component.

[0073] In block 425, the computer 24 determines whether the operating time since the last measurement, as monitored in block 420, is equal to or exceeds a sampling interval. The sampling interval may be defined as the time after the last measurement of the parameter of the power device 22 before triggering the next measurement of the parameter of the power device 22. If the operating time since the last measurement is less than the sampling interval, the process 400 continues in block 415. If the operating time since the last measurement is greater than or equal to the sampling interval, the process 400 continues in block 430.

[0074] In block 430, the computer 24 initiates a measurement mode. The computer 24 may set the device index n=1. During the measurement mode, the computer 24 may be programmed to measure one or more of the power devices 22 in the inverter 20. For example, in Figure 3 In the case of the inverter 20 shown, the computer 24 can be programmed to sequentially measure each of the power devices 22-1 to 22-6 in a loop. The computer 24 can set the device index n=1 to measure the first power device 22 (e.g., power transistor 22-1), and then increment the index to measure additional power devices 22. Once the device index n=1 is set, the process 400 continues at block 435.

[0075] In block 435, computer 24 is programmed to measure power device 22-n. To measure power device 22-n, computer 24 may be programmed to couple inverter 20 and measurement unit 26 so that the electrical nodes and signals to be measured (e.g., as described above with reference to Table 1) are available for measurement at measurement unit 26. For example, in the case of n=1, computer 24 is programmed to provide measurement unit 26 with access to gate terminal G1 and node L1 connected to power device 22-1 (coupled to source terminal S1), as well as signal IL1 output by current sensor CS1. Process 400 continues in block 440.

[0076] In block 440, the computer 24 is programmed to measure the power device 22-n via the measurement unit 26. The measurement unit 26 may monitor the current through the drain terminal of the power device 22-n based on the signal from the corresponding current sensor. In addition, the measurement unit 26 may monitor the voltage across the gate terminal and the source terminal of the power device 22-n.

[0077] For example, to measure the power device 22-1, the computer 24 can be programmed to turn off the power device 22-4. When the power device 22-4 is off, the current I1 through the node L1 is equal to the drain current of the power device 22-1. The measurement unit 26 can monitor the signal IL1 to determine the current through the node L1. The measurement unit 26 can then monitor the voltage between the gate terminal G1 of the power device 22-1 coupled to the node L1 and the source terminal S1 of the power device 22-1. Alternatively, the measurement unit 26 can apply a voltage between the gate terminal G1 and the source terminal S1 and cause the voltage to vary over time. Alternatively, the measurement unit 26 can monitor the voltage between the gate terminal G1 and the source terminal S1 while the power device 22-1 is operating to deliver power to the load 60 (which may include the motor 28) and is switching from the off state to the on state.

[0078] When current I1, as determined based on signal IL1, exceeds a predetermined threshold, measurement unit 26 measures the voltage across gate terminal G1 and source terminal S1. Based on this data, measurement unit 26 determines the threshold voltage of power device 22-1. Typically, the predetermined current is selected so that the voltage across gate terminal G1 and source terminal S1 equals the threshold voltage. The predetermined current of power device 22-1 is typically in the range of 100 nanoamperes to 100 milliamperes.

[0079] Additionally or alternatively, measurement unit 26 can measure the on-resistance of power device 22-1. The measurement unit can apply a voltage between gate terminal G1 and source terminal S1. Measurement unit 26 can also measure the voltage from power supply L1 and monitor signal IL1 to determine current I1. Measurement unit 26 can determine on-resistance = (voltage from power supply L1) / I1. Once the threshold voltage or on-resistance of power device 22-n is determined, process 400 then continues at block 445.

[0080] In block 445, the computer 24 determines whether the threshold voltage and / or on-resistance of the power device 22-n is outside a predetermined range. The predetermined range may be, for example, a specified operating range for the power device 22-n, or an operating range determined to be optimal for operation of the vehicle 10. If the threshold voltage or on-resistance of the power device 22-n is outside the predetermined range, the process 400 continues in block 450. Otherwise, the process 400 continues in block 455.

[0081] In block 450, the computer 24 sets a "calibration flag" for the power device 22-n. That is, the computer 24 stores a value in a memory associated with the computer 24, which is a calibration flag (e.g., a binary variable set to 1) indicating that the threshold voltage or on-resistance of the power device 22-n is outside a predetermined range. The calibration flag can be an indication that the computer 24 is performing adjustments on the power device 22-n. Process 400 then continues in block 455.

[0082] In block 455, the computer 24 determines whether the device index n exceeds or equals the total number m of power devices 22 in the inverter 20. If n=m, the process 400 ends. If the device index n is less than the total number m of power devices 22 in the inverter 20, the process 400 continues in block 460.

[0083] In block 460 , computer 24 increments device index n. Process 400 then continues in block 435 .

[0084] Figure 5A and Figure 5B is a diagram of an exemplary process for adjusting a parameter of power device 22. For example, the parameter to be adjusted may be a threshold or an on-resistance of power device 22. Process 500 begins in block 505.

[0085] In block 505, the vehicle 10 is turned on. The computer 24 in the vehicle 10 is activated. For example, this may mean that power is applied to the computer 24 or the computer 24 is awakened from a sleep mode or otherwise set to an active mode to initiate the process 500 for adjusting the parameters of the power device 22. Once the vehicle 10 is turned on and the computer 24 is activated, the process 500 continues in block 510.

[0086] In block 510, the computer 24 determines whether at least one calibration flag is set, indicating that the threshold voltage or on-resistance of at least one power device 22 is outside a predetermined range. If the calibration flag is not set, the process 500 ends. If the at least one calibration flag is set, the process 500 continues in block 515.

[0087] In block 515, the computer 24 determines a target adjustment time for adjusting a parameter of at least one power device 22 ("power device 22 to be adjusted"), wherein the threshold voltage or on-resistance is determined to be outside a predetermined range. The target adjustment time is defined herein as an estimated time required to heat the power device 22 to adjust the threshold voltage or on-resistance to a target threshold voltage or on-resistance. The target threshold voltage or on-resistance of the power device 22 to be adjusted may be, for example, an original threshold voltage or original on-resistance of the power device 22. For example, the computer 24 may maintain a record of the threshold voltage and / or on-resistance of the power device 22 at the time of manufacture. As another example, the target threshold voltage and / or on-resistance of the power device 22 to be adjusted may be a value within a predetermined range, or a value within a range based on the predetermined range.

[0088] For example, the target threshold voltage of the power device 22 to be adjusted may be a value within a range included in but less than a predetermined range. The predetermined range may be defined as V range-min ≤Predetermined range≤V range-max , where V range-min is the minimum voltage of the predetermined range and V range-max In this case, the range for adjusting the target threshold voltage of the power device 22 to be adjusted can be defined as (V range-min +x%)≤predetermined range≤(V range-max -x%), where x is a value selected to provide a certain operating margin after adjustment, such as 10. In the case where a single power device 22 is to be adjusted, the computer 24 determines the difference between the threshold voltage of the power device 22 to be adjusted and the target threshold voltage of the power device 22 to be adjusted.

[0089] Based on the difference between the target threshold voltage and the actual threshold voltage, and also based on the temperature at which the adjustment is performed, the computer 24 can determine an estimated adjustment time for adjusting the threshold of the power device 22 to be adjusted. The rate at which the threshold voltage is adjusted may depend on the temperature of the power device 22 during the adjustment process. The temperature of the power device 22 to be adjusted during the adjustment process is referred to herein as the adjustment temperature. For example, the adjustment temperature can be determined based on a temperature to which the power device 22 or other components of the vehicle 10 (such as the inverter 20, the pump 34, etc.) can be heated without damaging the power device 22 or other components, with a margin to allow for variations between vehicles 10. The adjustment temperature range is a range that includes the adjustment temperature (such as the adjustment temperature + / - 10%) as a target for controlling the adjustment temperature.

[0090] Based on the determined adjustment temperature and the rate of adjusting the threshold, an expected adjustment time can be calculated. The rate of adjusting the threshold can be determined based on the type of power device 22 to be adjusted. Alternatively, the rate of adjusting the threshold can be determined based on historical adjustment data of the power device 22 to be adjusted, as described below.

[0091] In some cases, the expected trim time may be determined from a table maintained by computer 24. For example, for a known trim temperature, the table may list the expected trim time as a function of the difference between the actual threshold voltage and the target threshold voltage of power device 22 based on one or both of device type data and device history data.

[0092] The computer 24 may maintain (i.e., store in memory) a record or history of adjustments made to the power device 22. The adjustment record may indicate the adjustment time required to adjust the power device 22 to be adjusted during a previous adjustment period. In this case, the expected adjustment time may be based in part on the adjustment time required for the previous adjustment. For example, the amount of threshold adjustment and the time of adjustment may be recorded for previous measurements. Based on the previous measurements, the rate of threshold adjustment may be determined to be equal to the threshold adjustment divided by the threshold adjustment time. The time for the current adjustment may be determined based on the adjustment rate calculated from the previous adjustment and the difference between the actual threshold voltage and the target threshold voltage.

[0093] In some cases, a tuning profile can be generated for tuning power device 22. The profile is a data set that includes a sequence of tuning times and corresponding tuning temperatures for device 22. For example, computer 24 can be programmed to heat power device 22 to a first temperature during a first tuning time, and then to a second temperature during a second tuning time.

[0094] In the event that more than one power device 22 has a threshold voltage outside of the predetermined range, the adjustment time determination may be made based on the power device 22 having the largest difference between the actual threshold voltage and the target threshold voltage.

[0095] If the parameter to be adjusted is on-resistance, a similar approach can be used to determine the adjustment time. A target on-resistance can be identified based on data associated with the power device 22-n. A difference between the actual on-resistance and the target on-resistance can be determined. Then, based on the difference between the target on-resistance and the actual on-resistance, and also based on the temperature at which the adjustment is performed, the computer 24 can determine an estimated adjustment time for adjusting the on-resistance of the power device 22-n to be adjusted. Once the adjustment time is determined, process 500 continues at block 520.

[0096] In block 520, the computer 24 requests authorization from the user to perform the adjustment process. For example, the computer 24 may send a message to the user via the HMI 50. The message may include information suggesting that the adjustment be performed on the power device 22 to be adjusted and also indicating the expected adjustment time. The message may also request authorization from the user to perform the adjustment. Once authorization is requested from the user, the process 500 continues in block 525.

[0097] At block 525, computer 24 determines whether the user has authorized the adjustment. For example, computer 24 may wait a predetermined time after requesting authorization from the user. If computer 24 receives input authorizing the adjustment, process 500 continues at block 530. If computer 24 does not receive input authorizing the adjustment within the predetermined time, process 500 ends.

[0098] In block 530, the computer 24 determines whether the vehicle 10 is turned off. For example, the computer 24 may monitor the vehicle ignition to determine if the ignition is switched to the off state. If the vehicle is turned off, the process 500 continues in block 535. If the vehicle 10 continues to operate, the process continues in block 525.

[0099] In block 535, the computer 24 initiates the adjustment. The computer 24 activates components in the vehicle 10 to heat the power devices 22 in the inverter 20. In one example, the computer 24 turns on the heating unit 38. In addition, the computer 24 activates the pump 34 so that coolant is pumped from the coolant tank 30, through the pump 34, further through the heating unit 38, through the inverter 20, and back to the coolant tank 30. The computer 24 controls the heating unit 38 to maintain the coolant within the adjustment temperature range described above. As noted above, in some cases, the coolant tank 30 may not be necessary. In these cases, the computer 24 activates the pump 34 so that coolant is pumped through the pump 34, further through the heating unit 38, through the inverter 22, and back to the pump 34.

[0100] To provide power to the heating unit 38, the vehicle 10 can be connected to an external power source, such as the power source 52. In this case, the computer 24 can send instructions to the user, for example, via the HMI 50, to plug the vehicle 10 into the power source 52. The heating unit 38 can receive power directly from the power source 52. Alternatively, the battery 46 can be charged from the power source 52, and the heating unit 38 can receive power from the battery 46.

[0101] In other cases, engine 29 may power heating unit 38. Heating unit 38 may receive power from battery 46 and may operate engine 29 to recharge battery 46. Once the conditioning process is initiated and power is provided to heating unit 38, process 500 continues at block 540.

[0102] At block 540, the computer 24 determines whether an input has been received to terminate the process 500. The input may be an input from a user indicating that the computer 24 should terminate the adjustment process. For example, the input may be a signal from the vehicle ignition indicating that the vehicle 10 has been turned on. As another example, the input may be an input from the vehicle 10 (e.g., based on user input) to terminate the adjustment process. If an input is detected, the process 500 ends. If no input is detected, the process 500 continues at block 545.

[0103] At block 545, computer 24 determines whether the adjusted run time is greater than or equal to the target adjusted run time. Adjusted run time is defined as the time during which the power device is heated by the vehicle component. If the adjusted run time is less than the target adjusted run time, process 500 continues at block 535. If the adjusted run time is greater than or equal to the target adjusted run time, process 500 continues at block 550.

[0104] In block 550, the computer 24 initiates measurement of the power device 22 being adjusted via the measurement unit 26. The computer 24 implements the measurement in a manner similar to that described above with reference to blocks 435 and 440. That is, in the case of threshold voltage adjustment, the computer 24 may send an instruction to the inverter 20 to apply a varying gate-source voltage to the power device 22 being adjusted. Then, when the drain current reaches a predetermined current, the measurement unit 26 may determine the threshold voltage of the power device 22 based on the gate-source voltage of the power device 22. In the case of on-resistance adjustment, the computer 24 may send an instruction to the inverter 20 to apply a voltage from the gate to the source of the power device 22 being adjusted. The computer 24 may also instruct the measurement unit to measure the drain-to-source current through the power device 22 being adjusted and the drain-to-source voltage of the power device 22 being adjusted. The on-resistance can be determined based on the drain-to-source voltage and the drain-to-source current of the power device 22 being adjusted. Once the threshold voltage measurement and / or determination of the on-resistance of the power device 22 is complete, process 500 continues at block 555 .

[0105] In block 555, the computer 24 determines whether the threshold voltage or on-resistance of the power device 22 being adjusted is within a target range. The target range is a range extending around the target threshold voltage or on-resistance, respectively. For example, the target threshold range can be + / - 10% of the target threshold voltage. If the threshold voltage is not within the target threshold range, the process continues in block 560. If the threshold voltage is within the target threshold range, the process continues in block 565.

[0106] In block 560 , the computer 24 maintains the calibration flag in a set state. The computer 24 also updates the current threshold and / or on-resistance data to reflect the actual threshold and / or on-resistance of the power device 22 to be adjusted. The process 500 then continues in block 515 .

[0107] In block 565 (which may follow block 555), the computer 24 resets the calibration flag, i.e., from "set" or binary 1 to unset or binary zero. The computer 24 also reports the status of the power device 22. The computer 24 may display a message on the HMI 50, for example, indicating that the adjustment process was successful. The computer 24 may also store data representing the actual parameters of the power device 22. The computer 24 may also provide the data to the server 12. As described above, the server 12 may use this data to generate statistics regarding the results of the adjustments performed on the power device 22. Once the calibration flag is reset and the status of the power device 22 is reported, the process 500 ends.

[0108] Figure 6A and Figure 6B An example vehicle 610 is shown that includes a mechanism for adjusting parameters of the power device 22. The example vehicle 610 includes the same or similar components as the vehicle 10, except that the vehicle 610 does not include the heating unit 38 or the motor 28, but instead includes a motor 628 and a valve 612. The motor 628 and the valve 612 are arranged so that heat from the motor 628 can be transferred to the coolant and used to heat the power device 22 in the inverter 20 during the regulation mode. Figure 6A Vehicle 610 is shown configured for normal operation. Figure 6B Vehicle 610 is shown configured for a regulation mode.

[0109] The vehicle 610 includes a valve 612. In a first position, used in normal mode, the valve directs coolant from the pump 34 directly to the inverter 20 via a pipe 639. In this mode, coolant is provided to cool the inverter 20.

[0110] Figure 6BVehicle 610 is shown in regulation mode. In regulation mode, computer 24 switches valve 612 to a second position. In the second position, valve 612 directs coolant from pump 34 to motor 628. Motor 628 can heat the coolant during regulation mode. In other words, motor 628 can operate to generate heat. Coolant can be directed through the motor to collect heat from the motor. The coolant is further directed to inverter 20 via pipe 640 to transfer heat from motor 28 to power devices 22 within inverter 20.

[0111] During adjustment, the computer 24 can monitor the coolant temperature and turn the motor on and off to adjust the coolant temperature within the target temperature range. The power to drive the motor can be received from an external power source 52, which can be, for example, an electrical outlet. Alternatively, the vehicle 610 can include an engine 29 that can be operated from time to time to charge the battery 46. In this case, the motor 628 can receive power from the battery 46.

[0112] In another example, a positive temperature coefficient (PTC) heater, such as a cabin heater, may be used to heat the coolant during the trim mode. A valve may be included in the vehicle to direct coolant flow through the PTC heater during the trim mode.

[0113] in conclusion

[0114] Computing devices (such as those discussed herein) typically each include instructions that can be executed by one or more computing devices (such as those identified above) and used to perform the blocks or steps of the above-described processes. For example, the process blocks discussed above can be embodied as computer-executable instructions.

[0115] Computer-executable instructions may be compiled or interpreted by a computer program created using a variety of programming languages ​​and / or technologies, including, but not limited to, Java, TM , C, C++, Visual Basic, Java Script, Perl, HTML, etc. Generally speaking, a processor (e.g., a microprocessor) receives instructions, for example, from a memory, a computer-readable medium, etc., and executes these instructions to perform one or more processes, including one or more of the processes described herein. Various computer-readable media can be used to store and transmit such instructions and other data in files. A file in a computing device is typically a collection of data stored on a computer-readable medium (such as a storage medium, random access memory, etc.).

[0116] Computer-readable media include any media that participate in providing data (e.g., instructions) that can be read by a computer. Such media can take many forms, including but not limited to non-volatile media, volatile media, etc. Non-volatile media include, for example, optical or magnetic disks and other permanent memories. Non-volatile media include dynamic random access memory (DRAM) that typically constitutes main memory. Common forms of computer-readable media include, for example, floppy disks, floppy disks, hard disks, magnetic tape, any other magnetic media, CD-ROMs, DVDs, any other optical media, punch cards, paper tape, any other physical media with hole patterns, RAM, PROMs, EPROMs, FLASH-EEPROMs, any other memory chips or cassettes, or any other media from which a computer can read.

[0117] All terms used in the claims are intended to be given their common and ordinary meanings as understood by those skilled in the art, unless otherwise expressly indicated herein. Specifically, use of singular articles such as "a," "an," "the," and the like should be understood to refer to one or more of the indicated elements, unless a claim expressly provides a limitation to the contrary.

[0118] The term "exemplary" is used herein in the sense of meaning an example; for example, reference to an "exemplary widget" should be understood as a reference merely to an example of a widget.

[0119] As used herein, the adverb "about" modifying a value or result means that the shape, structure, measurement, value, determination, calculation, etc. may deviate from the precisely described geometry, distance, measurement, value, determination, calculation, etc. because of imperfections in materials, machining, manufacturing, sensor measurements, calculations, processing time, communication time, etc.

[0120] In the accompanying drawings, the same reference numerals represent the same elements. In addition, some or all of these elements may be changed. With respect to the media, processes, systems, methods, etc. described herein, it should be understood that although the steps of such processes, etc. have been described as occurring according to a certain ordered sequence, such processes may be implemented using the described steps performed in an order other than the order described herein. It should also be understood that certain steps may be performed simultaneously, other steps may be added, or certain steps described herein may be omitted. In other words, the description of the process herein is provided for the purpose of illustrating certain embodiments and should in no way be construed as limiting the claimed invention.

[0121] According to the present invention, a computer is provided having: a processor; and a memory storing instructions executable by the processor such that the processor is programmed to: determine, based on measurements performed in a vehicle, that a parameter of a power device is outside a predetermined range; and actuate a component in the vehicle to heat the power device.

[0122] According to one embodiment, the processor is further programmed to: determine that the power device is heated within a predetermined time; perform a second measurement on the power device; determine that a parameter of the power device is within a target range based on the second measurement; and store a state of the power device.

[0123] According to one embodiment, the parameter of the power device outside the predetermined range is one of a threshold voltage and an on-resistance.

[0124] According to one embodiment, the processor is further programmed to determine a target time for heating the power device based on the measurement.

[0125] According to one embodiment, the processor is further programmed to: monitor a regulation time for the power device to be heated by the vehicle component; and actuate the vehicle component to stop heating the power device when the regulation time for the power device to be heated by the component is greater than or equal to a target time.

[0126] According to one embodiment, the instructions to the vehicle component include instructions executable to: activate a heating unit in the vehicle; and pump coolant along a coolant path to transfer heat from the heating unit to the power device.

[0127] According to one embodiment, the processor is further programmed to: actuate the vehicle component to perform measurements including: varying a gate-source voltage of the power device over time; monitoring current through the power device; and measuring the gate-source voltage when the current through the power device reaches a predetermined current.

[0128] According to one embodiment, determining that the power device is operating outside of a predetermined range includes programming to determine that a gate-source voltage when a current through the power device reaches a predetermined current is outside of a predetermined range.

[0129] According to one embodiment, the processor is further programmed to actuate the vehicle component to: request authorization to adjust the power device via the human-machine interface; and transmit a second instruction to the component based in part on receiving the authorization to adjust the power device.

[0130] According to one embodiment, requesting authorization to adjust the power device includes instructing the human-machine interface to: display a target time for heating the power device at the human-machine interface.

[0131] According to the present invention, a method is executable by a computer comprising: a processor; and a memory storing instructions executable by the processor, the instructions comprising: determining, based on measurements performed in a vehicle, that a parameter of a power device is outside a predetermined range; and actuating a component in the vehicle to heat the power device.

[0132] According to one embodiment, the above invention is further characterized by determining that the power device is heated within a predetermined time; performing a second measurement on the power device; determining that a parameter of the power device is within a target range based on the second measurement; and storing the state of the power device.

[0133] According to one embodiment, the above invention is further characterized in that a target time for heating the power device is determined based on the measurement.

[0134] According to one embodiment, the above invention is further characterized by monitoring an adjustment time of the power device being heated by the vehicle component; and actuating the vehicle component to stop heating the power device when the adjustment time of the power device being heated by the component is greater than or equal to a target time.

[0135] According to one embodiment, the above invention is further characterized by activating a heating unit in the vehicle; and pumping coolant along a coolant path to transfer heat from the heating unit to the power device.

[0136] According to one embodiment, the above invention is further characterized in that actuating a vehicle component to perform a measurement includes: varying a gate-source voltage of a power device over time; monitoring a current through the power device; and measuring the gate-source voltage when the current through the power device reaches a predetermined current.

[0137] According to one embodiment, determining that the parameter of the power device is outside the predetermined range includes determining that a gate-source voltage when the current through the power device reaches a predetermined current is outside the predetermined range.

[0138] According to one embodiment, the above invention is further characterized by requesting authorization to adjust the power device via the human-machine interface; and transmitting the second instruction to the component based in part on receiving the authorization to adjust the power device.

[0139] According to the present invention, a system is provided that includes a vehicle, the system having: a power device; a measuring device for measuring the output of the power device; and a computer, the computer including: a processor; and a memory storing instructions that are executable by the processor so that the processor is programmed to: determine, based on measurements performed in the vehicle by the measuring device, that a parameter of the power device is outside a predetermined range; and actuate a component in the vehicle to heat the power device.

[0140] According to one embodiment, the processor is further programmed to: determine that the power device is heated within a predetermined time; perform a second measurement on the power device; determine that a parameter of the power device is within a target range based on the second measurement; and store a state of the power device.

Claims

1. A method executable by a computer, the computer comprising: processor; and a memory storing instructions executable by the processor, the method comprising: determining, based on a measurement of an electrical parameter of the power switching device performed in the vehicle, that an electrical parameter of the power switching device is outside a predetermined range, wherein the electrical parameter of the power switching device that is outside the predetermined range is one of a threshold voltage and an on-resistance; as well as A component in the vehicle is actuated to heat the power switching device based on determining that an electrical parameter of the power switching device is outside of a predetermined range.

2. The method of claim 1, further comprising: Determining that the power switching device is heated within a predetermined time; performing a second measurement on the power switching device; determining, based on the second measurement, that the electrical parameter of the power switching device is within a target range; as well as The state of the power switch device is stored.

3. The method of claim 1 , further comprising: A target time for heating the power switch is determined based on the measurement.

4. The method of claim 3, further comprising: monitoring a settling time of heating of the power switching device by a component in the vehicle; as well as When the adjusted time that the power switching device is heated by the component in the vehicle is greater than or equal to the target time, the component in the vehicle is actuated to stop heating the power switching device.

5. The method of claim 1, further comprising: activating a heating unit in the vehicle; as well as Coolant is pumped along a coolant path to transfer heat from the heating unit to the power switching device.

6. The method of claim 1, further comprising: Actuating a component in the vehicle to perform the measurement comprises: varying a gate-source voltage of the power switching device over time; monitoring current through the power switching device; and When the current through the power switching device reaches a predetermined current, the gate-source voltage is measured.

7. The method of claim 6, wherein determining that the electrical parameter of the power switching device is outside the predetermined range comprises: It is determined that the gate-source voltage when the current through the power switching device reaches the predetermined current is outside the predetermined range.

8. The method of claim 1, further comprising: requesting authorization to adjust the power switching device via a human-machine interface; as well as A second instruction is transmitted to a component in the vehicle based in part on receiving authorization to adjust the power switch.

9. The method of claim 8, wherein requesting the authorization to adjust the power switch comprises: The target time for heating the power switch device is displayed on the human-machine interface.

10. A computer programmed to perform the method of any one of claims 1 to 9.

11. A vehicle comprising a computer programmed to perform the method of any one of claims 1 to 9.

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