INTEGRATED ON-BOARD AC CHARGER

Abstract

A switch is connected between a traction battery and a transfer circuit such that during a drive mode the switch is open and power from a traction battery bypasses field effect transistors of the transfer circuit and a transformer of the transfer circuit and flows through an inverter system controller to an electric machine and during a charge mode the switch is closed and power from a charging source flows sequentially through windings of the electric machine, the inverter system controller, the transformer and the switch to the traction battery.

Description

FIELD OF TECHNOLOGY

[0001] This disclosure relates to power systems for motor vehicles. GENERAL STATE OF THE ART

[0002] Unlike conventional vehicles with internal combustion engines, electric vehicles use electric motors for propulsion, drawing power from on-board energy storage systems, typically lithium-ion batteries.

[0003] Electric vehicles may require charging solutions. Certain on-board chargers convert AC power from a grid to DC power at a fixed rate. SUMMARY

[0004] A vehicle includes a traction battery, a power system comprising an electric machine including windings, a transfer circuit including a plurality of field-effect transistors and a transformer, and an inverter system controller connected between the electric machine and the transfer circuit, and a switch connected between the traction battery and the transfer circuit. The power system and switch are configured such that during a drive mode, the switch is open and power from the traction battery bypasses the field-effect transistors and the transformer and flows through the inverter system controller to the electric machine, and during a charge mode, the switch is closed and power from a charging source flows sequentially through the windings, the inverter system controller, the transformer, and the switch to the traction battery.

[0005] A method includes, in response to a drive mode, opening a switch connected between a traction battery and a transfer circuit including a plurality of field-effect transistors and a transformer such that power from the traction battery bypasses the field-effect transistors and the transformer and flows through an inverter system controller to windings of an electric machine; and, in response to a charge mode, closing the switch such that power from a charging source flows sequentially through the windings, the inverter system controller, the transformer, and the switch to the traction battery.

[0006] A motor vehicle power control system includes a controller programmed to close a switch connected between a traction battery and a transfer circuit and open a pair of switches of the transfer circuit in response to a charging mode such that power flows from a charging source through windings of an electric machine, an inverter system controller, a transformer of the transfer circuit, and the switch to the traction battery. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic diagram of an on-board AC charger connected between an AC grid and a traction battery. Fig. Figure 2 is a schematic representation of a vehicle and certain performance-related components therein. DETAILED DESCRIPTION

[0007] Embodiments are described in this specification. It should be understood, however, that the disclosed embodiments are merely examples, and other embodiments may take various and alternative forms. The figures are not necessarily to scale. Some features may be exaggerated or reduced to show details of specific components. Therefore, specific structural and functional details disclosed in this specification are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art.

[0008] Various features illustrated and described with respect to any of the figures may be combined with features illustrated in one or more other figures to produce embodiments not explicitly illustrated or described. The illustrated combinations of features provide representative embodiments for typical applications. However, various combinations and modifications of the features consistent with the teachings of this disclosure may be desirable for particular applications or implementations.

[0009] An on-board AC charger is typically a separate, closed-loop system consisting of electrical components separate from the traction inverter and motor. These systems may also include a power conversion module, adaptive charging control, thermal management, and a communications interface.

[0010] Some power conversion modules implement highly efficient, multi-stage conversion processes that convert AC power to DC power. They may incorporate semiconductor devices with low on-resistance and high thermal stability, reducing energy losses during conversion.

[0011] Adaptive charging controllers can use algorithms to monitor the battery's state of charge (SoC), temperature, and capacity, and adjust charging power according to speed and battery health requirements. These systems can also communicate with a power grid or a household energy management system to charge the vehicle during off-peak hours.

[0012] Thermal management systems can maintain desired temperatures of the charging components and battery during charging using active cooling techniques to dissipate heat.

[0013] Communication interfaces can support standard charging protocols and enable smart grid integration. Some can allow the vehicle to participate in demand response programs, where charging can be scheduled or modulated based on grid utilization.

[0014] With reference to Fig. 1, a typical on-board AC charger 10 includes diodes 12, 14, 16, 18, 20, 22, 24, active switches 26, 28, 30, 32, 34, 36, 38, 40, 42, 44, 46, capacitors 48, 50, inductors 52, 54, 56, 58, and a high-frequency transformer 60. Diodes 12, 14 are in series and diodes 16, 18 are in series. Diodes 12, 14 are in parallel with diodes 16, 18. Diode 20 and inductor 54 are in series, diode 22 and inductor 56 are in series, and diode 24 and inductor 58 are in series. The previous three sets of components are in parallel. One terminal of active switch 26 is connected between diode 24 and inductor 58. One terminal of active switch 28 is connected between diode 22 and inductor 56. One terminal of active switch 30 is connected between diode 20 and inductor 54. Active switches 32, 34 are in series. Active switches 36, 38 are in series. Active switches 40, 42 are in series.The active switches 44, 46 are in series. The active switches 32, 34 and 36, 38 are in parallel. The active switches 40, 42 and 44, 46 are in parallel. The capacitor 48 is in parallel with the active switch 32, 34. The capacitor 50 is in parallel with the active switches 44, 46. The high-frequency transformer 60 includes a pair of coils 62, 64. Terminals of the coil 62 are connected between the active switches 32, 34 and 36, 38. Terminals of the coil 64 are connected between the active switches 40, 42 and 44, 46.

[0015] The on-board AC charger 10 is connected between an AC grid 66 and a traction battery 68. The capacitor 50 is in parallel with the traction battery 68. In total, the on-board AC charger 10 includes seven diodes, eleven active switches, four inductors, two capacitors, and a high-frequency transformer to achieve three-phase interleaved on-board AC charging from the AC grid 66 to the traction battery 68. Some on-board AC chargers include more than the Fig. 1. As a result, such chargers can take up considerable space and have a certain weight.

[0016] As shown, the power factor correction circuit and the high-frequency transformer are necessary. The former serves to meet power factor requirements and regulatory standards for the AC grid 66, and the latter achieves galvanic isolation.

[0017] An on-board AC charger is proposed that uses components from an electric propulsion system, such as an inverter and a motor. This allows the use of existing and pre-existing vehicle electrical components to reduce the number of additional components and thus the size and weight of the on-board AC charger. In one example, an on-board AC charger uses an inverter system controller and motor windings. The components include four diodes, eight active switches, an inductor, a power capacitor, a high-frequency transformer, and a relay. Additional contactors are also used, but are already part of a high-voltage battery system.Compared to the on-board AC charger 10, this can reduce the component count by three diodes, three active switches, three inductors, and one power capacitor, while achieving three-phase interleaved on-board AC charging from a power grid to a traction battery. Furthermore, this can reduce the DC bus capacitance of the inverter because two capacitors are in parallel during vehicle operation.

[0018] With reference to Fig. 2, a vehicle 70 includes a traction battery 72, a transmission circuit 74, an inverter system controller 76, an electric machine 78 (e.g., a motor), a rectifier 80, a controller 82, a switch 84 (e.g., a relay), and an inductor 86. The transmission circuit 74 is connected between the traction battery 72 and the inverter system controller 76. The inverter system controller 76 is connected between the transmission circuit 74 and the electric machine 78. The electric machine 78 is connected between the inverter system controller 76 and the rectifier 80. The controller 82 is connected to the components of Fig. 2 in communication / exercises control of these. It can implement the algorithms and control strategies considered in this document.

[0019] The transfer circuit 74 includes a capacitor 88, active switches 90, 92, 94, 96, 98, 100, 102, 104 (e.g., field-effect transistors with body diodes, such as metal-oxide-semiconductor field-effect transistors), a high-frequency transformer 106, and switches 108, 110 (e.g., contactors). The active switches 90, 92 are in series. The active switches 94, 96 are in series. The active switches 98, 100 are in series. The active switches 102, 104 are in series. The active switches 90, 92 and 94, 96 are in parallel. The active switches 98, 100 and 102, 104 are in parallel. The capacitor 88 is in parallel with the active switches 90, 92.

[0020] The high-frequency transformer 106 includes a pair of coils 112, 114. Terminals of coil 112 are connected between the active switches 90, 92 and 94, 96. Terminals of coil 114 are connected between the active switches 98, 100 and 102, 104. The switches 108, 110 are located on positive and negative rails of the transfer circuit 74, respectively. One terminal of switch 108 shares a node 116 with a positive terminal of the traction battery 72 and a terminal of switch 84. The other terminal of switch 108 is connected to the inverter system controller 76. The switch 110 is connected between the traction battery 72 and the inverter system controller 76.

[0021] The inverter system controller 76 includes a capacitor 118 and active switches 120, 122, 124, 126, 128, 130 (e.g., field-effect transistors that include diodes, such as insulated-gate bipolar transistors or metal-oxide-semiconductor field-effect transistors). The active switches 120, 122 are in series. The active switches 124, 126 are in series. The active switches 128, 130 are in series. The capacitor 118 is connected in parallel with and between the active switches 102, 104 and 120, 122.

[0022] The electric machine 78 includes windings 132, 134, 136. One terminal of winding 132 is connected between the active switches 120, 122. One terminal of winding 134 is connected between the active switches 124, 126. One terminal of winding 136 is connected between the active switches 128, 130.

[0023] Rectifier 80 includes diodes 138, 140, 142, and 144. Diodes 138, 140 are connected in series. Diodes 142, 144 are connected in series. Diodes 138, 140 and 142, 144 are connected in parallel. The other terminals of each of the windings 132, 134, and 136 are connected together and share a node with the cathodes of diodes 138, 140.

[0024] During operation of the vehicle 70, the switches 108, 110 are closed, the switch 84 is open, the active switches 90, 92, 94, 96, 98, 100, 102, 104 are off, and an AC grid 146 (a charge source) is not connected to the vehicle 70. The inverter system controller 76 operates the active switches 120, 122, 124, 126, 128, 130 via pulse width modulation to convert DC power from the traction battery 72 to AC power to power the electric machine 78 and propel the vehicle 70. The traction battery 72 thus supplies power to the electric machine 78 and the vehicle 70 via the inverter system controller 76 during the motoring mode of operation. Generated power is sent back to the traction battery 72 via the electric machine 78 and the inverter system controller 76 during the generation mode. As suggested above, a size of the capacitor 118 may be selected relative to that of Fig.1. The capacitors 88 and 118 are in parallel during operation of the vehicle 70.

[0025] During on-board AC charging mode, inductor 86 is connected between diodes 138, 140 and AC grid 146 (AC grid 146 is connected to the input of rectifier 80), switches 108, 110 are open, and switch 84 is closed. The inverter system controller 76, windings 132, 134, 136, and rectifier 80 cooperate to achieve power factor correction by controlling the inverter system controller 76 to meet the efficiency, power factor requirements, and regulatory standards for the AC power grid 146. The active switches 120, 124, 128 are off, and the active switches 122, 126, 130 are pulse-width modulated. The active switches 90, 92, 94, 96, 98, 100, 102, 104 are controlled to increase the voltage for charging the traction battery 72. They are pulse-width modulated.Here, the high-frequency transformer 106 performs dual functions of voltage amplification and high-voltage isolation. When short circuits occur, the switch 84 can open to handle the situation.

[0026] These topologies and strategies can be used, for example, with 400V and 800V electrical drive systems. Because the inverter system controller 76 and the electric machine 78 are utilized as described, power factor correction circuits can be common to 400V and 800V electrical drive systems.

[0027] The algorithms, methods, or processes disclosed in this document may be executable by or implemented by a computer, controller, or processing device, which may include any dedicated electronic control unit or programmable electronic control unit. Furthermore, the algorithms, methods, or processes may be stored in many forms as computer- or controller-executable data and instructions, including, but not limited to, information permanently stored on non-writable storage media, such as read-only memory devices, and information modifiably stored on writable storage media, such as compact discs, random access memory devices, or other magnetic and optical media. The algorithms, methods, or processes may also be implemented in software-executable objects.Alternatively, the algorithms, methods, or processes may be implemented 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 a combination of firmware, hardware, and software components.

[0028] While exemplary embodiments are described above, these embodiments are not intended to describe all possible forms encompassed by the claims. Furthermore, the terms used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosed subject matter. For example, "controller" and "controllers" may be used interchangeably throughout this specification, since the functionality of a controller may be distributed across multiple controllers / modules, all of which may communicate using standard techniques.

[0029] As previously described, the features of various embodiments may be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments may have been described as providing advantages or being preferred over other prior art embodiments or implementations with respect to one or more desired characteristics, one of ordinary skill in the art will understand that one or more features or characteristics may be compromised to achieve desired overall system attributes depending on the specific application and implementation. These attributes may include, but are not limited to, strength, durability, marketability, appearance, installation, size, serviceability, weight, manufacturability, ease of assembly, etc.Thus, embodiments that are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics are not outside the scope of the disclosure and may be desirable for particular applications.

[0030] According to the present invention, a vehicle is provided comprising: a traction battery; a power system comprising an electric machine including windings, a transfer circuit including a plurality of field-effect transistors and a transformer, and an inverter system controller connected between the electric machine and the transfer circuit;and a switch connected between the traction battery and the transfer circuit, wherein the power system and the switch are configured such that during a drive mode, the switch is open and power from the traction battery bypasses the field-effect transistors and the transformer and flows through the inverter system controller to the electric machine, and during a charge mode, the switch is closed and power from a charging source flows sequentially through the windings, the inverter system controller, the transformer, and the switch to the traction battery.

[0031] According to one embodiment, the transfer circuit includes a pair of switches configured to be closed during the drive mode and open during the charge mode.

[0032] According to one embodiment, one of the pair of switches shares a node with a positive terminal of the traction battery and a terminal of the switch.

[0033] According to one embodiment, the invention is further characterized by a rectifier connected to the windings such that during the charging mode, power from the charging source flows first through the rectifier and then through the windings.

[0034] According to one embodiment, the rectifier includes a plurality of diodes and wherein the windings share a node with cathodes of some of the diodes.

[0035] According to one embodiment, the transfer circuit includes a capacitor configured to be connected in parallel with the traction battery when the switch is closed.

[0036] According to one embodiment, the invention is further characterized by a controller programmed to selectively open and close the switch in response to predetermined conditions.

[0037] According to one embodiment, some of the field effect transistors are connected on one side of the transformer and others of the field effect transistors are connected on another side of the transformer.

[0038] According to the present invention, a method includes: in response to a drive mode, opening a switch connected between a traction battery and a transfer circuit including a plurality of field-effect transistors and a transformer such that power from the traction battery bypasses the field-effect transistors and the transformer and flows through an inverter system controller to windings of an electric machine; and, in response to a charge mode, closing the switch such that power from a charging source flows sequentially through the windings, the inverter system controller, the transformer, and the switch to the traction battery.

[0039] In one aspect of the invention, the method includes, in response to the drive mode, closing a pair of switches of the transmission circuit.

[0040] In one aspect of the invention, the method includes, in response to the charging mode, opening the pair of switches.

[0041] According to the present invention, there is provided a motor vehicle power control system comprising: a controller programmed to, in response to a charging mode, close a switch connected between a traction battery and a transfer circuit and open a pair of switches of the transfer circuit such that power flows from a charging source through windings of an electric machine, an inverter system controller, a transformer of the transfer circuit, and the switch to the traction battery.

[0042] According to one embodiment, the controller is further programmed to open the switch and close the pair of switches in response to a drive mode such that power flows from the traction battery through the inverter system controller and to the electric machine while bypassing the switch and the transformer.

[0043] According to one embodiment, one of the pair of switches shares a node with a positive terminal of the traction battery and a terminal of the switch.

[0044] According to one embodiment, the invention is further characterized by a rectifier connected to the windings such that during the charging mode, power from the charging source flows first through the rectifier and then through the windings.

[0045] According to one embodiment, the transfer circuit includes a capacitor configured to be connected in parallel with the traction battery when the switch is closed.

[0046] According to one embodiment, the transmission circuit includes a plurality of field effect transistors, and wherein some of the field effect transistors are connected on one side of the transformer and others of the field effect transistors are connected on another side of the transformer.

Claims

[1] Vehicle comprising: a traction battery; a power system comprising an electric machine including windings, a transfer circuit including a plurality of field-effect transistors and a transformer, and an inverter system controller connected between the electric machine and the transfer circuit; and a switch connected between the traction battery and the transfer circuit, wherein the power system and the switch are configured such that during a drive mode the switch is open and power from the traction battery bypasses the field effect transistors and the transformer and flows through the inverter system controller to the electric machine, and during a charge mode the switch is closed and power from a charging source flows sequentially through the windings, the inverter system controller, the transformer, and the switch to the traction battery. [2] The vehicle of claim 1, wherein the transfer circuit includes a pair of switches configured to be closed during the drive mode and open during the charge mode. [3] The vehicle of claim 2, wherein one of the pair of switches shares a node with a positive terminal of the traction battery and a terminal of the switch. [4] The vehicle of claim 1, further comprising a rectifier connected to the windings such that, during the charging mode, power from the charging source flows first through the rectifier and then through the windings. [5] The vehicle of claim 4, wherein the rectifier includes a plurality of diodes and wherein the windings share a node with cathodes of some of the diodes. [6] The vehicle of claim 1, wherein the transfer circuit includes a capacitor configured to be connected in parallel with the traction battery when the switch is closed. [7] The vehicle of claim 1, further comprising a controller programmed to selectively open and close the switch in response to predetermined conditions. [8] The vehicle of claim 1, wherein some of the field effect transistors are connected on one side of the transformer and others of the field effect transistors are connected on another side of the transformer. [9] Method comprising: in response to a drive mode, opening a switch connected between a traction battery and a transfer circuit including a plurality of field-effect transistors and a transformer such that power from the traction battery bypasses the field-effect transistors and the transformer and flows through an inverter system controller to windings of an electric machine; and in response to a charging mode, closing the switch so that power flows from a charging source sequentially through the windings, the inverter system controller, the transformer and the switch to the traction battery. [10] The method of claim 9, further comprising, in response to the drive mode, closing a pair of switches of the transmission circuit. [11] The method of claim 10, further comprising, in response to the charging mode, opening the pair of switches. [12] Motor vehicle power control system, comprising: a controller programmed, in response to a charging mode, to close a switch connected between a traction battery and a transfer circuit and open a pair of switches of the transfer circuit such that power flows from a charging source through windings of an electric machine, an inverter system controller, a transformer of the transfer circuit, and the switch to the traction battery. [13] The automotive power control system of claim 12, wherein the controller is further programmed to open the switch and close the pair of switches in response to a drive mode such that power flows from the traction battery through the inverter system controller and to the electric machine while bypassing the switch and the transformer. [14] The automotive power control system of claim 12, wherein one of the pair of switches shares a node with a positive terminal of the traction battery and a terminal of the switch. [15] The automotive power control system of claim 12, further comprising a rectifier connected to the windings such that, during the charging mode, power from the charging source flows first through the rectifier and then through the windings.

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