Method and apparatus for integrated bi-directional charging

Abstract

An electric vehicle includes a drive system that performs a method of transferring power between the vehicle and an external location. The drive system includes a battery, a rectifier, and a processor. The rectifier is one of a two-stage rectifier and a multi-stage rectifier. The processor is configured to connect the rectifier between an alternating current (AC) port of the socket at an external location and the battery. The rectifier is configured to convert between AC power at an AC port outside the rectifier and vehicle-side direct current (DC) power of the rectifier for bidirectional transfer of power between the external location and the battery.

Description

Technical Field

[0001] The subject disclosure relates to connections between electric vehicles and an electrical grid, and more particularly, to systems and methods for bidirectionally transferring power between an electric vehicle and an electrical grid. Background Art

[0002] Electric vehicles need to be charged from time to time. Charging stations are available to charge electric vehicles using both alternating current (AC) and direct current (DC). Circuitry to accommodate both types of charging stations takes up space. Therefore, it is desirable to provide an efficient and compact circuit that can accommodate both types of charging. Summary of the invention

[0003] In an exemplary embodiment, a method for transmitting power between a vehicle and an external location is disclosed. A rectifier is connected between an alternating current (AC) port of an outlet at the external location and a battery, wherein the rectifier is one of a two-level rectifier and a multi-level rectifier. The rectifier converts between AC power at the AC port outside the rectifier and direct current (DC) power at the vehicle side of the rectifier to bidirectionally transmit power between the external location and the vehicle.

[0004] In addition to one or more features described herein, the vehicle also includes a first inverter, a winding machine, and a second inverter for DC power transmission, and the method also includes connecting a rectifier to the first inverter to use the first inverter, the winding machine, and the second inverter for AC power transmission, wherein the first inverter is one of a two-level inverter and a multi-level rectifier, and the second inverter is one of a two-level rectifier and a multi-level rectifier. The method also includes disconnecting the rectifier from the AC port and connecting the first inverter to the DC port of the socket for DC power transmission. The winding machine is an electric motor of the vehicle, and the method also includes disconnecting the electric motor from the vehicle for power transmission. The method also includes connecting the vehicle's drive system between the AC port and the first inverter, and using the inverter of the drive system as a rectifier and the motor winding of the drive system as an inductor. The method also includes transmitting power in one of a three-phase configuration and a single-phase configuration with a rectifier.

[0005] In another exemplary embodiment, a drive system for an electric vehicle is disclosed. The drive system includes a battery, a rectifier, and a processor. The rectifier is one of a two-stage rectifier and a multi-stage rectifier. The processor is configured to connect the rectifier between an alternating current (AC) port of an outlet at an external location and the battery. The rectifier is configured to convert between AC power at the AC port outside the rectifier and direct current (DC) power on the vehicle side of the rectifier so as to transfer power bidirectionally between the external location and the battery.

[0006] In addition to one or more features described herein, the drive system also includes a first inverter, a winding machine, and a second inverter for DC power transmission, wherein the processor is further configured to connect a rectifier between the AC port and the first inverter to allow AC power transmission using the first inverter, the winding machine, and the second inverter, wherein the first inverter is one of a two-level inverter and a multi-level inverter, and the second inverter is one of a two-level inverter and a multi-level inverter. The processor is also configured to disconnect the rectifier from the AC port and connect the first inverter to the DC port of the socket to allow DC power transmission. The winding machine is an electric motor of the vehicle, and the processor is also configured to disconnect the electric motor from the vehicle for power transmission. The drive system also includes a second drive system connected in series between the AC port and the first inverter, wherein the inverter of the second drive system is used as a rectifier, the motor winding of the second drive system is used as an inductor between the AC port and the rectifier, and the inverter of the second drive system is one of a two-level inverter and a multi-level inverter. The rectifier operates in one of a three-phase configuration and a single-phase configuration. The neutral node or the second inverter is located at one of: between two capacitors isolating the neutral node from the positive bus and the negative bus of the battery, and between the first sub-battery and the second sub-battery connected in series. The winding machine includes a battery side winding and a grid side winding, and the turns ratio between the battery side winding and the grid side winding is adjustable to a selected value.

[0007] In another exemplary embodiment, an electric vehicle is disclosed. The electric vehicle includes a battery, a rectifier, and a processor. The rectifier is one of a two-stage rectifier and a multi-stage rectifier. The processor is configured to connect the rectifier between an alternating current (AC) port of an outlet at an external location and the battery. The rectifier is configured to convert between AC power at the AC port outside the rectifier and direct current (DC) power on the vehicle side of the rectifier so as to bidirectionally transfer power between the external location and the battery.

[0008] In addition to one or more features described herein, the electric vehicle also includes a first inverter, a winding machine, and a second inverter for DC power transmission, wherein the processor is further configured to connect a rectifier between the AC port and the first inverter to allow AC power transmission using the first inverter, the winding machine, and the second inverter, wherein the first inverter is one of a two-level inverter and a multi-level inverter, and the second inverter is one of a two-level inverter and a multi-level inverter. The processor is also configured to disconnect the rectifier from the AC port and connect the first inverter to the DC port of the socket to allow DC power transmission. The winding machine is the electric motor of the vehicle, and the processor is also configured to disconnect the electric motor from the vehicle for power transmission. The electric vehicle also includes a drive system connected in series between the AC port and the first inverter, wherein the inverter of the drive system is used as a rectifier, and the motor winding of the drive system is used as an inductor between the AC port and the rectifier, and the inverter of the drive system is one of a two-level inverter and a multi-level inverter. The rectifier operates in one of a three-phase configuration and a single-phase configuration.

[0009] The above features and advantages and other features and advantages of the present disclosure will become apparent from the following detailed description when taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Other features, advantages and details appear, by way of example only, in the following detailed description, which refers to the accompanying drawings, in which:

[0011] Figure 1 An electric vehicle according to an exemplary embodiment is shown.

[0012] Figure 2 A driving circuit of a driving system of an electric vehicle in an embodiment is shown;

[0013] Figure 3 An alternative drive circuit is shown, where the AC port is connected to a front-end rectifier via a three-phase interface;

[0014] Figure 4 An alternative drive circuit for a motor including a front end rectifier and an AC port in a three-phase configuration is shown;

[0015] Figure 5 An alternative drive circuit is shown wherein the motor between the front end rectifier and the AC port is in a first single phase configuration;

[0016] Figure 6 An alternative drive circuit is shown in which the motor between the front end rectifier and the AC port is in a second single-phase configuration;

[0017] Figure 7 A first DC configuration of a drive circuit for transferring power between a battery and a universal charger via a DC port is shown;

[0018] Figure 8 A second DC configuration of the drive circuit for transferring power between a battery and a universal charger via a DC port is shown;

[0019] Fig. 9 An AC configuration of a drive circuit for transferring power between a battery and an external grid via an AC port is shown;

[0020] Fig.10 A diagram depicting a drive circuit in an alternative embodiment is shown;

[0021] Fig.11 A driving circuit in another alternative embodiment is shown;

[0022] Fig.12 A diagram depicting a winding machine along a longitudinal axis in an embodiment is shown;

[0023] Fig.13 A schematic diagram of a transmission system of an electric vehicle is shown;

[0024] Fig.14 is a flow chart of a method of preparing a vehicle to use an electric motor for power transfer purposes;

[0025] Fig.15 is a flow chart of a method for reconnecting an electric motor to a vehicle for driving purposes;

[0026] Fig.16 A two-level inverter in an exemplary embodiment is shown;

[0027] Fig.17 The branches of a flying capacitor type multilevel inverter are shown;

[0028] Fig.18 shows the branches of an X-type multilevel inverter in an embodiment;

[0029] Fig.19 shows the branches of an H-type dual multilevel inverter in an embodiment;

[0030] Fig. 20A shows the branches of a diode clamped multilevel inverter in an embodiment;

[0031] Fig. 20B shows the branches of an active clamped multilevel inverter in an embodiment;

[0032] Fig.21 shows the branches of a T-type multilevel inverter in an embodiment;

[0033] Fig. 22 Cascaded H-bridges of a multi-level inverter in an embodiment are shown;

[0034] Fig.23 A driving circuit of a driving system of an electric vehicle in another embodiment is shown;

[0035] Fig.24 shows a driving circuit of a driving system of an electric vehicle in another embodiment; and

[0036] Fig.25 A driving circuit of a driving system for an electric vehicle in another embodiment is shown. DETAILED DESCRIPTION

[0037] The following description is merely exemplary in nature and is not intended to limit the present disclosure, its application, or uses. It should be understood that throughout the drawings, corresponding reference numerals indicate the same or corresponding parts and features.

[0038] According to an exemplary embodiment, Figure 1 An electric vehicle 100 is shown. The electric vehicle 100 includes an electrical system 102 having a drive system 104 and an electric motor 106 that operates using power provided by the drive system. Figure 1 As shown, the electric vehicle 100 is shown as being plugged into an external power grid 108 or other external electrical device or location. The external power grid 108 may be a home, residence, office, charging station, etc. Note that the external power grid 108 may include more than one power source, but may also include other electrical components that are typically powered by the external power grid 108. For example, if the external power grid 108 is a home or residence, the electrical components may include lights, televisions, computers, clocks, appliances such as washing machines / dryers, electric stoves, refrigerators, etc. Electricity may flow between the external power grid 108 and the electric vehicle 100 in either direction (i.e., bidirectional). Thus, the external power grid 108 may be used to charge the drive system 104. Alternatively, the drive system 104 may be used to charge the external power grid 108 or to power one or more electrical components of the external power grid 108 (e.g., washing machines / dryers). It should be understood that the electric vehicle 100 may have more than one electric motor, and each electric motor may have an associated drive system.

[0039] The electric vehicle 100 also includes a controller 110. The controller 110 may include processing circuitry, which may include an application specific integrated circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) executing one or more software or firmware programs and a memory, a combinational logic circuit, and / or other suitable components that provide the described functionality. The controller 110 may include a non-transitory computer-readable medium storing instructions that, when processed by one or more processors of the controller 110, implement a method of controlling the operation of the drive system 104.

[0040] Figure 2 The drive circuit 200 of the drive system 104 of the electric vehicle 100 in the embodiment is shown. The drive circuit 200 includes a power supply or battery 202, a first inverter 204, a second inverter 206 and a winding machine 208. The first inverter 204 and the second inverter 206 are electrically separated from each other and can be powered using a separate power module and driver. The first inverter 204 and the second inverter 206 each include a plurality of transistors or MOSFETs suitable for conversion between direct current (DC) and alternating current (AC). The winding machine 208 includes a winding divided into two electrically insulated winding groups. Each winding group has its own neutral connection. The two winding groups share the same stator core and have the same rotor. The winding can be electromagnetically symmetrical about the winding machine to avoid any imbalance, increase the convenience of control, etc., but in other embodiments, it can be electromagnetically asymmetrical about the winding machine. The winding machine can be of any form (i.e., a winding field synchronous machine, a synchronous reluctance machine, an internal permanent magnet motor, a surface permanent magnet motor, an induction motor, etc.).

[0041] The first inverter 204 can be used to convert between DC power at the external grid 108 and AC power at the electric motor 106. The second inverter 206 can be used to convert between DC power at the battery 202 and AC power at the electric motor 106. The drive circuit 200 can be connected to the external grid 108 via a universal charger 210, which is a socket of the external grid including a DC port (DC port 212) and an AC port (AC port 214). The winding machine 208 is incorporated into the electric motor 106.

[0042] The drive circuit 200 includes a high voltage DC bus 216 for connecting to a high voltage socket of a DC port 212 and a low voltage DC bus 218 for connecting to a low voltage socket of the DC port 212. A first DC port switch 220 controls the connection between the DC port 212 and the high voltage DC bus 216. A second DC port switch 222 controls the connection between the DC port 212 and the low voltage DC bus 218. An AC bus 224 extends between the AC port 214 and a front end rectifier 226. An AC port switch 228 on the AC bus 224 controls the connection between the AC port 214 and the front end rectifier 226. An inductor (L1) may be provided on the AC bus 224. The front end rectifier 226 decouples AC / DC power transmission between the AC port 214 and other components of the drive circuit 200 (e.g., the first inverter 204).

[0043] In various embodiments, the first inverter 204 may be a two-level inverter or a multi-level inverter, the second inverter 206 may be a two-level inverter or a multi-level inverter, and the front-end rectifier 226 may be a two-level inverter or a multi-level inverter. The front-end rectifier 226 may also be a one-level rectifier, a multi-level rectifier, or a Vienna rectifier, which are types of two-level inverters or multi-level inverters. Figure 16-22 Examples of a two-level inverter or a multi-level inverter are shown.

[0044] The battery contactor switch 230 is located between the battery 202 and the high voltage DC bus 216. The battery contactor switch 230 can be turned on (closed) during the driving mode (to operate the electric vehicle 100), and can be turned off or on (opened or closed) during the charging mode. During the operation of the front end rectifier 226 during AC charging, the switch 232 between the low voltage DC bus 218 and the battery 202 can be opened to disconnect the battery and the low voltage DC bus. Figure 2 As shown, the front end rectifier 226 is a single phase rectifier. However, this is not meant to be a limitation of the present invention.

[0045] Figure 3-6 The driver circuit 200 is shown in various alternative embodiments. Figure 3-6 Each of the first inverter 204, the second inverter 206, and the front-end rectifier 226 may be a two-level inverter or a multi-level inverter, an example of which is shown in FIG. Figure 16-22 Shown in. Figure 3 An alternative drive circuit 300 is shown in which the AC port 214 is connected to the front end rectifier 226 via a three-phase interface including a first bus 302, a second bus 304, and a third bus 306. The first bus 302 includes a first switch 308 and a first inductor 310. The second bus 304 includes a second switch 312 and a second inductor 314. The third bus 306 includes a third switch 316 and a third inductor 318.

[0046] In various embodiments, the first inverter 204, the second inverter 206, and the winding machine 208 operate as an electrical system of a first motor drive (a first drive system) of the electric vehicle 100. Figure 4-6 In the embodiment, the second motor drive (second drive system) of the electric vehicle 100 can be used to achieve the same Figure 3 The front-end rectifier 226 in the second motor drive can be used as the inductors 310, 314, and 318, and the inverter of the second motor drive can be used as the front-end rectifier 226.

[0047] Figure 4An alternative drive circuit 400 in a three-phase configuration is shown, which includes a motor 402 between a front-end rectifier 226 and an AC port 214. The motor 402 includes three winding branches 404, 406, 408. Switches 410, 412, and 414 connect each of the three winding branches 404, 406, 408 of the motor 402 to a socket of the AC port 214, respectively. When the switches 410, 412, 414 are closed, the motor 402 can operate on the AC power transmitted between the AC port 214 and the front-end rectifier 226. The disconnect switches between the three winding branches 404, 406, 408 can be opened during power transmission operation to disconnect the neutral connection between the three winding branches 404, 406, 408, and can be closed when the electric vehicle is operated in a propulsion mode.

[0048] Figure 5 An alternative drive circuit 500 is shown in which the motor 402 is in a first single-phase configuration between the front-end rectifier 226 and the AC port 214. A first switch 504 is located between the AC port 214 and the upstream ends of the three winding branches 404, 406, 408 of the motor 402. A second switch 506 connects the downstream end of the motor 402 back to the AC port 214. When the first switch 504 and the second switch 506 are closed, the motor 402 can be operated with all three winding branches 404, 406, 408 tapped into one phase.

[0049] Figure 6 An alternative drive circuit 600 is shown in which the motor 402 is in a second single-phase configuration between the front end rectifier 226 and the AC port 214. A first switch 604 is connected between the AC port 214 and the first winding branch 404, and a second switch 606 is connected between the AC port 214 and the third winding branch 408. The first switch 604 and the second switch 606 are closed to operate the motor 402 connected to the neutral point.

[0050] Figure 7A first DC configuration 700 of the drive circuit 200 is shown for transferring power between the battery 202 and the universal charger 210 via the DC port 212. The controller 110 or processor can control the configuration of the switches to select the first DC configuration 700. The controller 110 can select the DC configuration when DC power transfer is required and when the voltage of the battery 202 is the same as the voltage of the DC port 212. In the first DC configuration 700, the first DC port switch 220, the second DC port switch 222, and the battery contact switch 230 are closed, while the AC port switch 228 is open, thereby disabling the front end rectifier 226, the first inverter 204, the second inverter 206. As a result, from the perspective of the front end functionality, the first inverter 204 and the second inverter 206, the winder 208, and the front end rectifier 226 are removed from the drive circuit. The battery 202 is therefore directly connected to the DC port 212. Power can be transferred via Figure 7 The illustrated current path 702 flows between the battery 202 and the universal charger 210 in either direction. Figure 7 Each of the first inverter 204, the second inverter 206 and the front-end rectifier 226 in the embodiment of the present invention may be a two-level inverter or a multi-level inverter, an example of which is shown in FIG. Figure 16-22 Shown in.

[0051] Figure 8 A second DC configuration 800 of the drive circuit 200 for transferring power between the battery 202 and the universal charger 210 via the DC port 212 is shown. When DC power transfer is required and when the voltage of the battery 202 is different from the voltage of the DC port 212, the controller 110 or processor selects the second DC configuration 800. In the second DC configuration 800, the first DC port switch 220 and the second DC port switch 222 are closed, while the battery contact switch 230 and the AC port switch 228 are open. As a result, from a functional perspective, the first inverter 204, the second inverter 206, and the winder 208 are included in the drive circuit 200, while the front end rectifier 226 is not included in the drive circuit. Figure 8 Each of the first inverter 204, the second inverter 206 and the front-end rectifier 226 in the embodiment of the present invention may be a two-level inverter or a multi-level inverter, an example of which is shown in FIG. Figure 16-22 Shown in.

[0052] like Figure 82 and AC current 804, the current can flow through the circuit in either direction. The first inverter 204 and the second inverter 206 are used as a dual active bridge DC-DC converter, LLC converter or CLLC converter. The grid-side DC current 802 is converted into AC current 804 at the first inverter 204. The AC current 804 flows between the first inverter 204 and the grid-side winding of the winding machine 208 including the first set of coils. On the grid side of the winding machine 208, the AC current 804 flows between the second inverter 206 and the battery-side winding of the winding machine 208, which includes the second set of coils. The second inverter 206 converts the DC current from the battery into an AC current flowing to the winding machine 208. The first set of coils and the second set of coils enable the winding machine 208 to act as a transformer, which electrically isolates the AC current 804 from the grid-side DC current 802. Power may flow through the winding machine 208 in either direction between the battery 202 and the DC port 212 .

[0053] Fig. 9 An AC configuration 900 of the drive circuit 200 is shown for transferring power between the battery 202 and the external grid 108 via the AC port 214. In the AC configuration 900, the battery contactor switch 230 is open, and the first DC port switch 220 and the second DC port switch 222 are open. The AC port switch 228 is closed, thereby connecting the front end rectifier 226 to the AC port 214.

[0054] In one embodiment, AC power is transmitted from the external grid 108 to the electric vehicle 100. AC current 902 flows from the AC port 214 to the front-end rectifier 226. The front-end rectifier 226 converts the AC current 902 into a DC current 904 that flows to the first inverter 204. The first inverter 204 converts the DC current 904 into a grid-side AC current 906 that flows to the winding machine 208. At the winding machine 208, the grid-side AC current 906 flows through the grid-side winding (i.e., the first set of coils) to induce a battery-side AC current 908 in the battery-side winding (i.e., the second set of coils). The battery-side AC current 908 flows to the second inverter 206, which converts the battery-side AC current into a DC current 910 for charging the battery 202.

[0055] In another embodiment, AC power is transmitted from the electric vehicle 100 to the external grid 108. DC current 910 flows from the battery 202 to the second inverter 206. The second inverter 206 converts the DC current 910 into a battery-side AC current 908 that is sent to the winding machine 208. At the winding machine 208, the battery-side AC current 908 flows through the battery-side winding (i.e., the second set of coils) to induce a grid-side AC current 906 in the grid-side winding (i.e., the first set of coils). The grid-side AC current 906 is sent to the first inverter 204, which converts the grid-side AC current into a DC current 904. The DC current 904 is sent from the first inverter 204 to the front-end rectifier 226. The front-end rectifier 226 converts the DC current 904 into an AC current 902 that flows to the AC port 214. Fig. 9 Each of the first inverter 204, the second inverter 206 and the front-end rectifier 226 in the embodiment of the present invention may be a two-level inverter or a multi-level inverter, an example of which is shown in FIG. Figure 16-22 Shown in.

[0056] Fig.10 A diagram 1000 is shown depicting the drive circuit 200 in an alternative embodiment. A first set of Y capacitors 1002 extends across the electrodes of the battery 202 to isolate the second inverter 206 from ground 1004. In addition, a second set of Y capacitors 1006 is located between the high voltage DC bus 216 and the low voltage DC bus 218 to isolate the first inverter 204 from ground 1004. The first set 1002 and the second set 1006 further provide electrical isolation across the winding machine 208. Fig.10 Each of the first inverter 204, the second inverter 206 and the front-end rectifier 226 in the embodiment of the present invention may be a two-level inverter or a multi-level inverter, an example of which is shown in FIG. Figure 16-22 Shown in.

[0057] Fig.11 A matrix converter that can be used within the drive circuit 200 in an embodiment is shown. The matrix converter 1102 converts AC current into AC current and can be inserted into the drive circuit 200 to replace the front-end rectifier 226 and the first inverter 204. For a three-phase winding, the matrix converter 1102 can operate using 9 switches instead of the 12 or more switches it replaces (i.e., 6 or more transistors of the front-end rectifier 266 and 6 or more transistors of the first inverter 204). When the matrix converter 1102 is used, the input inductor L1 is not required. Figure 4 The front-end rectifier 226 may be a two-level inverter or a multi-level inverter, an example of which is shown in FIG. Figure 16-22 Shown in.

[0058] Fig.12A diagram 1200 depicting a winding machine 208 along a longitudinal axis in an embodiment is shown. In an embodiment, the winding machine 208 is a three-phase permanent magnet motor and includes a stator 1202 and a rotor 1204. The rotor 1204 includes one or more permanent magnets 1238 forming a D axis 1222 (direct axis). The stator 1202 includes a grid side winding including a first set of coils and a battery side winding including a second set of coils. The first set of coils and the second set of coils are interlaced with each other. Because the winding machine 208 is a three-phase permanent magnet motor, the grid side winding includes a first grid side coil 1206, a second grid side coil 1208, and a third grid side coil 1210, and the battery side winding includes a first battery side coil 1216, a second battery side coil 1218, and a third battery side coil 1220.

[0059] The first grid side coil 1206 and the first battery side coil 1216 form a first thermocouple pair 1240. The second grid side coil 1208 and the second battery side coil 1218 form a second thermocouple pair 1244. The third grid side coil 1210 and the third battery side coil 1220 winding W2 form a third thermocouple pair 1246. The A axis is the magnetic flux axis of the coil. A first A axis 1224 is shown for the grid side winding and a second A axis 1226 is shown for the battery side winding. The direction of rotation 1228 of the rotor 1204 is shown. The grid side winding uses +i q 1230 consumes power from the grid. Battery side winding W2 uses -i q 1232 supplies power to the battery.

[0060] Fig.13 A schematic diagram 1300 of a drive train for an electric vehicle 100 is shown. When power is being transferred into or out of the electric vehicle 100, the electric motor 106 (i.e., the winder 208) is disconnected from the rest of the vehicle so that rotation of the electric motor during power transfer does not cause the vehicle to move. The electric motor 106 is shown connected to an axle 1302 of the electric vehicle 100 via a first clutch 1304, a first gear set 1306, a second clutch 1308, and a second gear set 1310. The first clutch 1304 can be disengaged to separate the winder 208 from the rest of the electric vehicle 100.

[0061] Fig.14 1400 is a flow chart of a method for preparing a vehicle for use with an electric motor 106 for power transfer purposes. At box 1402, the vehicle is in park. At box 1404, the electric motor 106 is disconnected from the rest of the vehicle, such as by disengaging the first clutch 1304. At box 1406, a power level, speed, and operating frequency for the power transfer are selected. At box 1408, a winding machine is used for power transfer.

[0062] Fig.151500 is a flow chart of a method for reconnecting the electric motor 106 to the vehicle for driving purposes. In box 1502, power transmission between the vehicle and the external power grid is stopped. In box 1504, the electric motor is switched to electric mode using a first inverter (externally powered) or a second inverter (powered by a battery). In box 1506, the speed of the electric motor 106 is reduced or decreased to restore the kinetic energy of the electric motor. In box 1508, the clutch is engaged when the speed of the electric motor drops below a selected speed threshold. In box 1510, the battery contact switch 230 is opened to discharge the high voltage DC bus. In box 1512, the vehicle returns to a safe mechanical and electrical state.

[0063] Fig.16 A two-level inverter 1600 in an exemplary embodiment is shown. The two-level inverter 1600 includes at least one branch (e.g., a first branch 1602, a second branch 1604, a third branch 1606) extending from a positive bus 1608 to a negative bus 1610. Each branch includes two switches connected in series between the positive bus 1608 and the negative bus 1610. For example, the first branch 1602 includes a switch S1 and a switch S2. The phase winding is connected to the branch between the two switches of the branch. For example, the phase winding 1612 is connected to the first branch 1602 between the switch S1 and the switch S2.

[0064] Fig.17 A branch 1700 of a flying capacitor type multilevel inverter is shown. The branch 1700 includes four switches (labeled S1, S2, S3, and S4) connected in series between a positive bus 1608 and a negative bus 1610. The node between switch S1 and switch S2 is connected to a node between switch S3 and switch S4 through a flying capacitor 1702.

[0065] Fig.18 A branch 1800 of an X-type multilevel inverter in an embodiment is shown. The branch 1800 includes a first sub-branch 1802 and a second sub-branch 1804, the first sub-branch 1802 includes switches S1, S2, S3 and S4 sequentially connected in series between the positive bus 1608 and the negative bus 1610, and the second sub-branch 1804 includes switches S5, S6, S7 and S8 sequentially connected in series between the positive bus and the negative bus. A first diode D1 is connected between a node between switch S3 and switch S4 and a node between switch S5 and switch S6. A second diode D2 is connected between a node between switch S7 and switch S8 and a node between switch S1 and switch S2.

[0066] Fig.19A branch 1900 of an H-type dual multilevel inverter in an embodiment is shown. The branch 1900 includes a first sub-branch 1902 and a second sub-branch 1904, the first sub-branch 1902 including switches S1 and S2 connected in series between the positive bus 1608 and the negative bus 1610, and the second sub-branch 1904 including switches S5 and S6 connected in series between the positive bus and the negative bus. The third sub-branch 1906 is connected from a node between the switch S1 and the switch S2 and a node between the switch S5 and the switch S6. In an embodiment, the third sub-branch may include additional switches S3 and S4 or a bidirectional switch, however this is not meant to be limiting.

[0067] Fig. 20A 1 shows a branch 2000 of a diode clamped multilevel inverter in an embodiment. The branch 2000 includes four switches (labeled S1, S2, S3, and S4) that are sequentially connected in series between the positive bus 1608 and the negative bus 1610. The first diode D1 connects the neutral node N to the node between the switch S1 and the switch S2. Similarly, the second diode D2 connects the neutral node N to the node between the switch S3 and the switch S4. The neutral node N is located outside the inverter and is isolated from the positive bus 1608 by the first capacitor 2002 and isolated from the negative bus by the second capacitor 2004. In another embodiment, the battery (i.e. Figure 2 The battery 202) may be divided into a first sub-battery and a second sub-battery connected in series, and a neutral node N may be located between the first sub-battery and the second sub-battery.

[0068] Fig. 20B FIG. 2 shows a branch 2010 of an active clamped multilevel inverter in an embodiment. The active clamped multilevel inverter includes switches S1, S2, S3, and S4. The first clamp switch 2012 replaces Fig. 20A The first diode D1 and the second clamp switch 2014 are replaced Fig. 20A The second diode D2.

[0069] Fig.21 A branch 2100 of a T-type multilevel inverter in an embodiment is shown. The branch 2100 includes a first switch S1 and a second switch S2 connected in series between the positive bus 1608 and the negative bus 1610. A neutral line 2102 connects a node between the first switch S1 and the second switch S2 to a neutral node N. The neutral line 2102 includes a switch S3 and a switch S4 or a bidirectional switch, however this is not meant to be limiting.

[0070] Fig. 22A cascaded H-bridge 2200 of a multilevel inverter in an embodiment is shown. For illustrative purposes, the cascaded H-bridge 2200 includes a first H-type dual multilevel inverter 2202 and a second H-type dual multilevel inverter 2204. A first cascade line 2206 is connected between a switch of a first branch 2208 of the first H-type dual multilevel inverter 2202 and a second branch 2214 of the second H-type dual multilevel inverter 2204. A second cascade line 2216 is connected between a switch of a first branch 2212 of the second H-type dual multilevel inverter 2204 and a second branch 2210 of the first H-type dual multilevel inverter 2202.

[0071] exist Figure 16-22 In the inverter shown, the switch can be a transistor or a diode, such as but not limited to a Si IGBT transistor, an antiparallel diode, a SiC MOSFET, a SiC Schottky diode, a GaN switch / diode, a Ga2O3 switch / diode, a diamond-based power device, etc.

[0072] Fig.23 A drive circuit 2300 of a drive system 104 of an electric vehicle 100 in another embodiment is shown. The drive circuit 2300 supports single-phase and three-phase AC charging. The drive circuit 2300 includes a power source or battery 202, a first inverter 204, a second inverter 206, and a winding machine 208. The first inverter 204 and the second inverter 206 are electrically separated from each other and can be powered using separate power modules and drivers. The first inverter 204 and the second inverter 206 each include a plurality of transistors or MOSFETs suitable for converting between direct current (DC) and alternating current (AC). Each of the first inverter 204, the second inverter 206, and the front-end rectifier 226 can be a two-stage inverter or a multi-stage inverter, such as a Vienna rectifier, an example of which is shown in FIG. Figure 16-22 Shown in.

[0073] The first inverter 204 can be used to connect to the external power grid 108 ( Figure 1 ) and the DC power at the electric motor 106 ( Figure 1 ) at the power supply 106. The second inverter 206 can be used to convert between the DC power at the battery 202 and the AC power at the electric motor 106. The drive circuit 200 can be connected to the external power grid 108 via a universal charger 210, which is a socket of the external power grid including a DC port (DC port 212) and an AC port (AC port 214). The winding machine 208 is incorporated in the electric motor 106.

[0074] The drive circuit 2300 includes a high voltage DC bus 216 for connecting to a high voltage socket of the DC port 212 and a low voltage DC bus 218 for connecting to a low voltage socket of the DC port 212. The first DC port switch 220 controls the connection between the DC port 212 and the high voltage DC bus 216. The second DC port switch 222 controls the connection between the DC port 212 and the low voltage DC bus 218. The AC port 214 is connected to the front end rectifier 226 via a three-phase interface including a first bus 302, a second bus 304, and a third bus 306. The first bus 302 includes a first switch 308 and a first inductor 310. The second bus 304 includes a second switch 312 and a second inductor 314. The third bus 306 includes a third switch 316 and a third inductor 318.

[0075] The first pair of isolation capacitors 2302 and 2304 establish a first neutral node N1 between the high voltage DC bus 216 and the low voltage DC bus 218, thereby allowing the first inverter 204 to operate as a multi-level inverter with a neutral point (eg, T-type, diode clamped, active clamped, etc.).

[0076] The second pair of isolation capacitors 2306 and 2308 establish a second neutral node N2 between the positive and negative buses of the battery 202, thereby allowing the second inverter 206 to operate as a multi-level inverter using a neutral point (eg, T-type, diode clamped, active clamped, etc.).

[0077] The front end rectifier 226 outputs to a positive voltage line 2310 connected to the high voltage DC bus 216, a negative voltage line 2312 connected to the low voltage DC bus 218, and a neutral voltage line 2314 connected to the first neutral node N1. During operation of the front end rectifier 226 during AC charging, a switch 2320 between the low voltage DC bus 218 and the battery 202 may be opened to disconnect the battery and the low voltage DC bus.

[0078] Fig.24 A drive circuit 2400 of the drive system 104 of the electric vehicle 100 in another embodiment is shown. The drive circuit 2400 supports single-phase and three-phase AC charging, where the neutral grid is directly connected to the neutral point of the DC link capacitor to eliminate leakage current and improve electromagnetic charging. The drive circuit 2400 includes Fig.23 The components of the driving circuit 2300 and the neutral line 2402 connected from the neutral node of the universal charger 210 to the neutral voltage line 2314 and thus to the first neutral node N1. The neutral line 2402 can also be connected as an input to the front end rectifier 226. A switch 2404 on the neutral line 2402 can open or close the connection to the first neutral node N1. Another switch 2406 on the neutral line 2402 can open or close the connection to the front end rectifier 226.

[0079] Fig.25 FIG. 2 shows a driving circuit 2500 of a driving system 104 of an electric vehicle 100 in another embodiment. The driving circuit 2500 includes Figure 2 206. The winding machine 208 includes a first interconnect 2502 connected to the first inverter 204 and a second interconnect 2504 connected to the second inverter 206. The winding machine 208 includes a winding 2506 connected between the first interconnect 2502 and the second interconnect 2504. The windings are grouped according to battery-side windings and grid-side windings, and each battery-side winding is paired with a grid-side winding. The windings can be adjustable windings, where the turns ratio (e.g., the turns ratio between the battery-side winding and its associated grid-side winding A2) can be adjusted to increase or decrease the voltage transmission through the winding machine 208. For example, the winding pairs can be configured and interconnected to have different turns ratios (i.e., two integer turns ratios, such as 1:1, 2:3, 3:2, 1:3, 3:1, etc. and fractional turns ratios, such as 1:1.2, 2.5:1, etc.). The turns ratio may be selected to allow battery 202 to be charged at different states of charge (SOC) from different grid-side voltages at AC port 214 .

[0080] Note that the present invention is mainly discussed with respect to the power grid, but can be used with respect to any external device. When the present invention is used with respect to any external device, "grid side" can refer to "external side".

[0081] The terms "one" and "an" do not indicate a limitation of quantity, but rather indicate the presence of at least one of the referenced items. The term "or" means "and / or", unless the context clearly indicates otherwise. References to "an aspect" throughout the specification mean that a particular element (e.g., feature, structure, step, or characteristic) described in conjunction with that aspect is included in at least one aspect described herein, and may or may not be present in other aspects. In addition, it should be understood that the described elements may be combined in any suitable manner in various aspects.

[0082] When an element such as a layer, film, region, or substrate is referred to as being “on” another element, it can be directly on the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” another element, there are no intervening elements present.

[0083] Unless otherwise indicated herein, all test standards are the most recent standards in effect as of the filing date of the present application or, if priority is claimed, the filing date of the earliest priority application in which the test standards appear.

[0084] Unless defined otherwise, technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0085] Although the above disclosure has been described with reference to exemplary embodiments, it will be appreciated by those skilled in the art that various changes may be made and equivalents may be substituted for its elements without departing from the scope thereof. In addition, many modifications may be made to adapt specific situations or materials to the teachings of the disclosure without departing from the essential scope of the disclosure. Therefore, it is intended that the disclosure is not limited to the specific embodiments disclosed, but will include all embodiments falling within its scope.

Claims

1. A method of transmitting power between a vehicle and an external location, comprising: connecting a rectifier between an alternating current (AC) port of an outlet at an external location and the battery, wherein the rectifier is one of a two-stage rectifier and a multi-stage rectifier; and Converts between AC power at an AC port outside the rectifier and direct current (DC) power on the vehicle side of the rectifier to transfer power bidirectionally between the external location and the vehicle.

2. The method according to claim 1, wherein: The vehicle also includes a first inverter, a winder, and a second inverter for DC power transmission, and the method also includes connecting the rectifier to the first inverter to perform AC power transmission using the first inverter, the winder, and the second inverter, wherein the first inverter is one of a two-level inverter and a multi-level rectifier, and the second inverter is one of a two-level rectifier and a multi-level rectifier. 3 . The method of claim 2 , further comprising disconnecting the rectifier from the AC port and connecting the first inverter to a DC port of the outlet for DC power transfer.

4. The method according to claim 2, wherein: The winding machine is an electric motor of a vehicle, and the method further includes disconnecting the electric motor from the vehicle for power transfer.

5. The method of claim 2, further comprising connecting a drive system of a vehicle between the AC port and the first inverter, and using an inverter of the drive system as the rectifier and a motor winding of the drive system as an inductor.

6. A driving system for an electric vehicle, comprising: Battery; A rectifier, wherein the rectifier is one of a two-stage rectifier and a multi-stage rectifier; as well as A processor is configured to connect a rectifier between an alternating current (AC) port of an outlet at an external location and a battery, the rectifier being configured to convert between AC power at the AC port external to the rectifier and direct current (DC) power at a vehicle side of the rectifier to transfer power bidirectionally between the external location and the battery.

7. The drive system of claim 6, further comprising a first inverter, a winding machine, and a second inverter for DC power transmission, wherein the processor is further configured to connect a rectifier between the AC port and the first inverter to allow AC power transmission using the first inverter, the winding machine, and the second inverter, wherein the first inverter is one of a two-level inverter and a multi-level inverter, and the second inverter is one of a two-level inverter and a multi-level inverter.

8. The drive system according to claim 7, wherein: The processor is also configured to disconnect the rectifier from the AC port and connect the first inverter to the DC port of the outlet to allow DC power transfer.

9. The drive system according to claim 7, wherein: The winding machine is an electric motor of a vehicle, and the processor is further configured to disconnect the electric motor from the vehicle for power transfer.

10. The drive system according to claim 7 further includes a second drive system connected in series between the AC port and the first inverter, wherein the inverter of the second drive system is used as the rectifier, the motor winding of the second drive system is used as an inductor between the AC port and the rectifier, and the inverter of the second drive system is one of a two-level inverter and a multi-level inverter.

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