Power module gate oxide self-recovery
By using the closed-loop power module gate oxide self-recovery control algorithm in parking mode, closing the switch and maintaining it at a predefined temperature, the problem of low recovery efficiency of gate oxide layer in the prior art is solved, extending the life of the inverter system controller and reducing energy consumption.
Patent Information
- Application Number
- CN202510071895.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-01-22
- Filing Date
- 2025-01-16
- Publication Date
- 2025-08-01
AI Technical Summary
The prior art is inefficient in restoring the gate oxide layer in the inverter system controller, and the use of a positive temperature coefficient heater will shorten its lifespan and increase vehicle energy consumption.
The closed-loop power module gate oxide self-recovery control algorithm is used to remove the captured charge and restore the threshold voltage by closing the switch in parking mode and using the inverter system controller to maintain the switch at a predefined temperature for a certain period of time.
Effectively restore the threshold voltage of the gate oxide layer, extending the life of the inverter system controller, and reducing energy consumption and thermal impact on other components.
Smart Images
Figure CN120415221A_ABST
Abstract
Description
Technical Field
[0001] The present disclosure relates to an automotive power system. Background Art
[0002] A motor vehicle may use electrical energy to power an electric motor. The electric motor may convert this electrical energy into mechanical energy to propel the vehicle. The motor vehicle may include various power electronic devices to regulate and store electrical energy. Summary of the Invention
[0003] An automotive power system includes: a traction battery; an electric motor including a Y-connected winding; an inverter system controller connected between the traction battery and the electric motor; and a switch having a terminal directly connected to the center point of the traction battery and a terminal directly connected to the neutral point of the Y-connected winding.
[0004] A method includes: during a parking mode, closing the switch to directly connect the center point of the traction battery and the neutral point of the Y-connected winding of the electric motor; and operating an inverter system controller connected between the traction battery and the electric motor to maintain its switch at a predefined temperature for a predefined period of time.
[0005] A vehicle includes: a traction battery; an electric motor; an inverter system controller connected between the traction battery and the electric motor; a switch connected between the traction battery and the winding of the electric motor; and a controller that, when the vehicle is not being driven, closes the switch and operates the inverter system controller to maintain its switch at a predefined temperature for a predefined period of time. Brief Description of the Drawings
[0006] Figure 1 is a schematic diagram of an automotive power system.
[0007] Figure 2 is a block diagram of a closed-loop power module gate oxide self-recovery control algorithm.
[0008] Figure 3 shows associated with Figure 1 the automotive power system of Figure 2 and the simulated power switch current waveform associated with the closed-loop power module gate oxide self-recovery control algorithm of
[0009] Figure 4 shows associated with Figure 1 the automotive power system of Figure 2 and the simulated power switch temperature waveform associated with the closed-loop power module gate oxide self-recovery control algorithm of
[0010] Figure 5 shows associated withFigure 1 associated with the automotive power system and Figure 2 the simulated power switch loss waveform associated with the closed-loop power module gate oxide self-recovery control algorithm.
[0011] Figure 6 shows the Figure 1 associated with the automotive power system and Figure 2 the simulated battery current waveform associated with the closed-loop power module gate oxide self-recovery control algorithm.
[0012] Figure 7 shows the Figure 1 associated with the automotive power system and Figure 2 the simulated phase current and battery voltage waveforms associated with the closed-loop power module gate oxide self-recovery control algorithm. Detailed Description
[0013] Embodiments are described herein. However, it should be understood that the disclosed embodiments are merely examples and other embodiments may take various and alternative forms. The drawings are not necessarily to scale. Some features may be exaggerated or minimized to show details of particular components. Thus, the specific structural and functional details disclosed herein should not be construed as limiting, but merely as a representative basis for teaching one of ordinary skill in the art.
[0014] The various features shown and described in any one of the reference drawings can be combined with features shown in one or more other drawings to produce embodiments not explicitly shown or described. Combinations of the features shown provide representative embodiments for typical applications. However, for a particular application or implementation, various combinations and modifications of the features may be desirable that are consistent with the teachings of this disclosure.
[0015] An electric vehicle can use an inverter system controller to provide power to a motor to propel the vehicle. The inverter system controller can use insulated gate bipolar transistors or silicon carbide devices to convert DC power to AC power to supply the motor and convert AC to DC to charge the battery. These power devices are some of the important components of the inverter system controller.
[0016] These devices require a certain gate voltage to optimize efficiency and operate properly. The threshold voltage is the voltage at which the device first begins to conduct, and the gate voltage from the gate driver circuit is selected to be greater than the threshold voltage of the device based on the manufacturer's specifications. Based on this, the gate drive circuit is constructed and operates at one voltage to turn on the device and at another voltage to turn off the device. As the device ages and the gate oxide layer deteriorates, the threshold voltage for turning on and off the device also changes. This will result in more losses and, in some cases, will cause the gate drive circuit to be unable to operate the power device at all. These types of problems may require replacing the inverter system controller. The main cause of this problem is due to trapped charges in the gate oxide layer of the device. These trapped charges change the threshold voltage, which in turn changes the turn-on and turn-off voltages of the device.
[0017] Depending on the operating parameters and environmental conditions, the device can go through three aging stages. The first stage is the situation where the device is in its normal operation and there are no changes. The second stage can be the situation where the threshold voltage begins to decrease due to trapped charges. The third stage can be the situation where Fowler-Nordheim tunneling begins and the threshold voltage begins to rise continuously. The later stages are the situations where more power losses and inefficient operation of the device may become apparent.
[0018] Generally, methods for restoring the gate oxide include heating to a temperature of 120 °C for 30 minutes for one hour or longer. This existing method uses the vehicle's positive temperature coefficient heater or heat pump. Using this method, the coolant in the circuit must be heated. Another option is to direct the coolant to the motor and use the motor to heat the coolant. A third option is to turn the vehicle's gas engine on and off to keep the battery charged to operate the positive temperature coefficient heater. In the context of an electric vehicle, this option uses a plug and electricity to enable the positive temperature coefficient heater to heat the coolant.
[0019] These techniques may have drawbacks. The positive temperature coefficient heater is inefficient and uses power from the battery to heat the coolant. The coolant must be pumped and heated throughout the duration of the annealing process, which can cause unnecessary heating of other components in the circuit. Such cycling may shorten the life of the positive temperature coefficient heater. The positive temperature coefficient heater may require an increase in size and may require additional cooling routes and valves.
[0020] The present disclosure contemplates strategies and components for restoring the device threshold voltage or returning it as close as possible to the first-stage threshold voltage. This includes a device self-annealing method for removing trapped charges in the device.
[0021] Reference Figure 1, vehicle 10 includes a traction battery 12, an inverter system controller 14, an electric motor 16, a switch 18, and a controller 20. The inverter system controller 14 is connected between the traction battery 12 and the electric motor 16. The controller 20 communicates with / applies control to the components of the vehicle 10.
[0022] The traction battery 12 includes two sets of battery cells 22, 24, thus defining a center point therebetween.
[0023] The inverter system controller 14 includes a DC-link capacitor 26, current sensors 28, 30, 32, and power switches Q1, Q2, Q3, Q4, Q5, Q6, which have corresponding gates G1, G2, G3, G4, G5, G6 and junction temperature sensors Tj1, Tj2, Tj3, Tj4, Tj5, Tj6. The power switches Q1, Q2 are connected in series and define the first phase bridge of the inverter system controller 14, the power switches Q3, Q4 are connected in series and define the second phase bridge of the inverter system controller 14, and the power switches Q5, Q6 are connected in series and define the third phase bridge of the inverter system controller 14. The phase bridges are connected in parallel with each other and in parallel with the DC-link capacitor 26. Each of the current sensors 28, 30, 32 is arranged to detect the current associated with one of the phase bridges.
[0024] The electric motor 16 includes a Y-connected winding 34, thus defining a neutral point.
[0025] The terminals of the switch 18 tap the neutral point of the Y-connected winding 34. The other terminal of the switch 18 taps the center point of the traction battery 12 between the sets of battery cells 22, 24. When closed, the switch 18 directly connects the neutral point and the center point.
[0026] Reference Figure 2, at operation 36, a difference is taken between a reference temperature (e.g., 120 °C) Tj_Ref and one of the junction temperatures Tji (i = 1, 2, 3,......, 6). The resulting difference is provided to the proportional-integral block PI1. At operation 40, the output of the proportional-integral block PI1 is multiplied by the output from the feedback block 38. The phase currents are summed at operation 42. At operation 44, a difference is taken between the resulting product from operation 40 and the resulting sum from operation 42. The resulting difference is provided to block 46, which includes multiplication operations 48, 50, difference operation 52, proportional-integral block PI2, and an inverter gate 54 arranged as shown. The output from the square-wave generator 56 is provided to the feedback block 38 and block 46. The outputs from block 46 and the triangular-wave generator 58 are provided to the comparator 60. The resulting output is provided to AND gates 62, 64. The output from the square-wave generator 56 is provided to AND gate 62 and inverter gate 66. The output from inverter gate 66 is provided to AND gate 64. The output from AND gate 62 affects the control of gates G1, G3, G5. The output from AND gate 64 affects the control of gates G2, G4, G6.
[0027] When the vehicle 10 is being driven, the switch 18 is open. The proposed strategy is disabled, and the inverter system controller 14 and the motor 16 are controlled by a conventional control strategy.
[0028] When the vehicle 10 is not being driven (e.g., when parked) and recovery of the power switches Q1, Q2, Q3, Q4, Q5, Q6 is required, the switch 18 is closed and a closed-loop power module gate oxide self-recovery control algorithm is executed to maintain the junction temperature at a predefined temperature for a predefined duration (e.g., 120 °C for 30 minutes to 1 hour or longer, if needed). This process can be repeated whenever the threshold voltage of the device increases or decreases outside the range of the first-stage threshold voltage, which can be detected via known sensors and techniques.
[0029] Tj_Ref is the target junction temperature of power switches Q1, Q2, Q3, Q4, Q5, Q6, which is set to 120 °C in this example. Depending on the type of power switch, etc., other temperatures may be required. The feedback temperature comes from junction temperature sensors Tj1, Tj2, Tj3, Tj4, Tj5, Tj6. It can be the temperature of a single device or the average temperature of all power switches Q1, Q2, Q3, Q4, Q5, Q6. A proportional-integral (PI) controller PI1 is used to control the actual junction temperature of power switches Q1, Q2, Q3, Q4, Q5, Q6, and its output is the target current that is the sum of the three winding currents. A second PI controller PI2 is used to make the motor winding current track the reference current, where the gate control signals G1, G2, G3, G4, G5, G6 control power switches Q1, Q2, Q3, Q4, Q5, Q6 respectively. The carrier signal has a frequency fsw that defines the switching frequency of power switches Q1, Q2, Q3, Q4, Q5, Q6. The square wave has a duty cycle of 50%, and its frequency fo defines the fundamental frequency of the current of power switches Q1, Q2, Q3, Q4, Q5, Q6.
[0030] This strategy will heat power switches Q1, Q2, Q3, Q4, Q5, Q6 and maintain their junction temperatures at the target temperature (e.g., 120 °C), which achieves the recovery of the threshold voltage of the device (or returns it as close as possible to the first-stage threshold voltage). At the same time, the battery cell groups 22, 24 maintain the same state of charge without affecting the performance of the traction battery 12.
[0031] Figures 3 to 7 The simulation results are shown when the proposed strategy works to remove the trapped charge in the device to recover the device. In this example, the target junction temperature is 120 °C, switch 18 is closed, fo = 50 Hz, fsw = 10 kHz, and the coolant temperature is 70 °C. Other values of the control parameters can be used based on the simulation or test results. Therefore, all power switches Q1, Q2, Q3, Q4, Q5, Q6 conduct current simultaneously.
[0032] Figure 3 The currents of power switches Q1, Q2 are shown. These currents and the switching of the device result in power losses and increase the temperature of the device, as shown in Figure 4 and Figure 5 Each switch has a power loss of 416 W, which helps to maintain the switch junction temperature at 120 °C. Figure 6 The currents of the battery cell groups 22, 24 are shown, where the positive and negative currents with a frequency of 50 Hz will maintain the constant state of charge of both. Moreover, Figure 7 The battery voltage and each phase current of the Y-connected winding 34 are shown.
[0033] The algorithms, methods, or processes disclosed herein may be delivered to or implemented by a computer, controller, or processing device, which may include any dedicated electronic control unit or programmable electronic control unit. Similarly, the algorithms, methods, or processes may be stored in various forms as data and instructions executable by a computer or controller, including but not limited to information permanently stored on a non-writable storage medium such as a read-only memory device and information alterably stored on a writable storage medium such as an optical disc, a random access memory device, or other magnetic and optical media. The algorithms, methods, or processes may also be implemented as software-executable objects. Alternatively, the algorithms, methods, or processes may be embodied, in whole or in part, using suitable hardware components such as application specific integrated circuits, field programmable gate arrays, state machines, or other hardware components or devices, or combinations of firmware, hardware, and software components.
[0034] Although the above describes exemplary embodiments, these embodiments are not intended to describe all possible forms covered by the claims. The words used in the specification are descriptive words rather than limiting words, and it should be understood that various changes may be made without departing from the spirit and scope of these disclosure materials. For example, the terms "controller" and "a plurality of controllers" may be used interchangeably herein because the functions of the controller may be distributed across several controllers / modules, which may all communicate via standard techniques.
[0035] As previously described, the features of the various embodiments may be combined to form additional embodiments that may not be explicitly described or shown in the present invention. Although the various embodiments may have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art should recognize that one or more features or characteristics may be compromised to achieve the desired overall system attributes, depending on the specific application and implementation. These attributes may include, but are not limited to: strength, durability, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. To this end, embodiments described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of this disclosure and may be desirable for a particular application.
[0036] According to the present invention, there is provided an automotive power system having: a traction battery; an electric motor including a Y-connected winding; an inverter system controller connected between the traction battery and the electric motor; and a switch having a terminal directly connected to the center point of the traction battery and a terminal directly connected to the neutral point of the Y-connected winding.
[0037] According to an embodiment, the invention is further characterized by a controller programmed to close the switch during a parking mode and operate the inverter system controller to maintain its switches at a predefined temperature for a predefined period of time.
[0038] According to an embodiment, the controller is further programmed to operate the inverter via closed-loop control to maintain the switch at the predefined temperature for the predefined period of time.
[0039] According to an embodiment, the controller is further programmed to open the switch after expiration of the predefined period of time.
[0040] According to an embodiment, the traction battery includes two sets of battery cells, and a center point is therebetween the two sets of battery cells.
[0041] According to an embodiment, the invention is further characterized by a controller programmed to close the switch during a parking mode and operate the inverter system controller to maintain its switches at a predefined temperature for a predefined period of time such that the state of charge of the two sets of battery cells is the same.
[0042] According to the invention, a method includes: during a parking mode, closing a switch to directly connect a center point of a traction battery and a neutral point of a Y-connected winding of a motor; and operating an inverter system controller connected between the traction battery and the motor to maintain its switches at a predefined temperature for a predefined period of time.
[0043] In one aspect of the invention, the operation is performed via closed-loop control.
[0044] In one aspect of the invention, the method includes opening the switch after expiration of the predefined period of time.
[0045] In one aspect of the invention, the operation causes the state of charge of the groups of battery cells on each side of the center point to be the same.
[0046] According to the invention, there is provided a vehicle having: a traction battery; a motor; an inverter system controller connected between the traction battery and the motor; a switch connected between the traction battery and a winding of the motor; and a controller programmed to, when the vehicle is not being driven, close the switch and operate the inverter system controller to maintain its switches at a predefined temperature for a predefined period of time.
[0047] According to an embodiment, the winding is a Y-connected winding, and the switch is connected to the neutral point of the Y-connected winding.
[0048] According to an embodiment, the traction battery includes two sets of battery cells and a center point therebetween, and wherein the switch is connected to the neutral point.
[0049] According to an embodiment, the controller is further programmed to operate the inverter system controller to maintain its switch at the predefined temperature for the predefined period of time such that the state of charge of each set of battery cells is the same.
[0050] According to an embodiment, the controller is further programmed to open the switch after expiration of the predefined period of time.
[0051] According to an embodiment, the controller is further programmed to operate the inverter system controller via closed-loop control to maintain its switch at a predefined temperature for a predefined period of time.
Claims
1. An automotive power system, comprising: A traction battery; An electric motor, the electric motor including a Y-connected winding; An inverter system controller connected between the traction battery and the electric motor; And A switch having a terminal directly connected to the center point of the traction battery and a terminal directly connected to the neutral point of the Y-connected winding.
2. The automotive power system according to claim 1, further comprising a controller programmed to close the switch during a parking mode and operate the inverter system controller to maintain its switches at a predefined temperature for a predefined period of time.
3. The automotive power system according to claim 2, wherein the controller is further programmed to operate the inverter via closed-loop control to maintain the switch at the predefined temperature for the predefined period of time.
4. The automotive power system according to claim 2, wherein the controller is further programmed to open the switch after expiration of the predefined period of time.
5. The automotive power system according to claim 1, wherein the traction battery includes two sets of battery cells, and wherein the center point is between the two sets of battery cells.
6. The automotive power system according to claim 5, further comprising a controller programmed to close the switch during a parking mode and operate the inverter system controller to maintain its switches at a predefined temperature for a predefined period of time such that the state of charge of the two sets of battery cells is the same.
7. A method, comprising: During a parking mode, closing a switch to directly connect the center point of a traction battery and the neutral point of a Y-connected winding of an electric motor; And operating an inverter system controller connected between the traction battery and the electric motor to maintain its switches at a predefined temperature for a predefined period of time.
8. The method according to claim 7, wherein the operation is performed via closed-loop control.
9. The method according to claim 7, further comprising opening the switch after expiration of the predefined period of time.
10. The method according to claim 7, wherein the operation causes the state of charge of each set of battery cells on each side of the center point to be the same.
11. A vehicle, comprising: A traction battery; An electric motor; An inverter system controller connected between the traction battery and the electric motor; A switch connected between the traction battery and the winding of the electric motor; And A controller programmed to close the switch and operate the inverter system controller to maintain its switches at a predefined temperature for a predefined period of time when the vehicle is not being driven.
12. The vehicle according to claim 11, wherein the winding is a Y-connected winding, and the switch is connected to the neutral point of the Y-connected winding.
13. The vehicle according to claim 11, wherein the traction battery includes two sets of battery cells and a center point therebetween, and wherein the switch is connected to the neutral point.
14. The vehicle according to claim 13, wherein the controller is further programmed to operate the inverter system controller to maintain its switches at the predefined temperature for the predefined period of time such that the state of charge of the respective groups of battery cells is the same.
15. The vehicle according to claim 11, wherein the controller is further programmed to operate the inverter system controller via closed-loop control to maintain its switches at a predefined temperature for a predefined period of time.