Power conversion and dual electric drive

Abstract

An electric power conversion and dual electric drive device (2), a system comprising the device (2), a method (12) of operating the device (2) and a computer program for performing the method (12) are provided, which enable charging of a dual drive electric vehicle (EV) from a three-phase power grid without generating any torque, while utilizing all power electronics existing for the traction system and the motor inductance. Thus, space is saved and power density, efficiency and reliability are improved.

Description

Technical Field

[0001] This invention relates to charging in electric vehicle (EV) applications. To this end, the invention provides a power conversion and dual-electric drive device, a system including the device, a method for operating the device, and a computer program for performing the method. Background Technology

[0002] Most EV architectures rely on physically separate charging and traction functions, implemented by the on-board charger (OBC) and traction converter / inverter, respectively. As the name suggests, the OBC is always located on the vehicle, requires dedicated space, must be placed inside the vehicle, and cannot provide any additional functionality while the vehicle is moving. This translates to higher capital expenditure (CAPEX) and operating expenditure (OPEX).

[0003] However, charging and driving functions of an EV are not typically used simultaneously. Exemplary attempts to combine charging and driving functions in the same hardware imply numerous significant limitations.

[0004] For example, fully integrated solutions are limited in terms of functionality and operation. This makes EV systems lack flexibility and fails to eliminate the anxieties of most EV users.

[0005] To charge from a three-phase power grid, additional non-shared converters, multiple motors, or multiphase motors can be used. In other cases, charging from a three-phase power grid generates torque. Obviously, this is detrimental to the efficiency and lifespan of mechanical components and produces noise and vibration. Summary of the Invention

[0006] Given the aforementioned disadvantages, the goal of both single-phase and three-phase charging operations is to reduce the overall size and cost of the charging and traction drive systems in EV applications.

[0007] This and other objectives are achieved by means of embodiments defined in the appended independent claims. Further embodiments are set forth in the dependent claims, as well as in the following description and drawings.

[0008] A first aspect of the present invention provides a power conversion and dual-electric drive device. The device includes: a first power converter and a second power converter, each including three branches; a first motor and a second motor, each including three open-end stator windings, the three open-end stator windings each having a first end and a second end; a first power switch and a second power switch. The first end of the stator winding of the first motor is connected to a corresponding branch of the three branches of the first power converter. The first end of the stator winding of the second motor is connected to a corresponding branch of the three branches of the second power converter. The second ends of the stator windings of the first motor are connected together and have the same potential. The second ends of the stator windings of the second motor are connected together and have the same potential. The first power switch is used to selectively disconnect one second end of the second end of the stator winding of the first motor from all other second ends of the second end to establish at most two different potentials; the second power switch is used to selectively disconnect one second end of the second end of the stator winding of the second motor from all other second ends of the second end to establish at most two other different potentials.

[0009] The dual electric drive used in this article can refer to an electric drive that uses two independently controllable motors.

[0010] As used herein, a power converter can refer to a device capable of converting electrical energy from one form to another (e.g., converting between AC and DC and / or vice versa), changing voltage or frequency, or some combination thereof. Specifically, a power converter can include a switch-mode power converter.

[0011] The term "stator" as used in this article can refer to the stationary part of a rotating system, such as an electric motor. In an electric motor, the stator may include multiple windings to provide a rotating magnetic field that drives the rotor.

[0012] The open terminals used in this article can refer to the internal terminals of the stator windings in an electric motor that are accessible and reconfigurable.

[0013] The term "power switch" as used herein may refer to a switch designed for high-voltage and / or high-current applications. Specifically, a power switch may include power semiconductor devices such as insulated-gate bipolar transistors (IGBTs).

[0014] The device described in the first aspect enables the EV to achieve a charging mode that integrates with a three-phase power grid without generating any torque, and can utilize all existing power electronics devices in the traction system and motor inductors. Therefore, space can be saved and power density, efficiency, and reliability can be improved.

[0015] According to one implementation of the first aspect, the device further includes a third power switch for selectively combining two of the established different potentials, the two potentials relating to the majority of the stator windings of the first motor and the minority of the stator windings of the second motor.

[0016] This increases the possibility of connectivity for single-phase charging in conjunction with the device and provides the ability to couple the motor.

[0017] According to one implementation of the first aspect, the first power switch is used to keep the second ends of the stator windings of the first motor continuously connected to each other to establish a single different potential; the second power switch is used to keep the second ends of the stator windings of the second motor continuously connected to each other to establish a single different other potential.

[0018] This configuration enables the EV to operate in traction mode within a configuration that includes two power switches.

[0019] According to one implementation of the first aspect, the first power switch is used to keep the second ends of the stator windings of the first motor from being disconnected from each other to establish a single different potential; the second power switch is used to keep the second ends of the stator windings of the second motor from being disconnected from each other to establish another single different potential; and the third power switch is used not to combine any of the established different potentials.

[0020] This configuration enables the EV to achieve traction mode in a configuration that includes three power switches.

[0021] According to one implementation of the first aspect, the established different potentials can be connected to two corresponding branches of a single-phase power grid interface, which can be connected to the device.

[0022] According to one implementation of the first aspect, the first power switch is used to disconnect one of the second terminals of the stator winding of the first motor from all other second terminals of the second terminal to establish at most two different potentials; the second power switch is used to disconnect one of the second terminals of the stator winding of the second motor from all other second terminals of the second terminal to establish at most two different other potentials; the third power switch is used to combine the two potentials of the established different potentials, the two potentials involving the majority of the stator winding of the first motor and the minority of the stator winding of the second motor; the established different potentials can be connected to three corresponding branches of a three-phase power grid interface, which can be connected to the device.

[0023] According to one implementation of the first aspect, at least one of the first power converter and the second power converter is configured to operate according to a direct torque control, field-oriented control, model predictive control or open-loop control strategy, and to adjust the torque of the corresponding motor according to a corresponding torque reference.

[0024] The torque used in this article can refer to the rotational equivalent of the linear force generated by the motor to propel the EV.

[0025] This increases the customizability for various EV needs.

[0026] According to one implementation of the first aspect, at least one of the first power converter and the second power converter is used to adjust the electrical parameters on the demand side of the first power converter and the second power converter.

[0027] This enables bidirectional operation of the at least one power converter and the device. Therefore, the device can charge energy storage devices such as batteries from the power grid and generate torque using the stored electricity. Furthermore, if needed, the device can return the stored electricity to the power grid.

[0028] According to one implementation of the first aspect, at least one of the first power converter and the second power converter is used to perform AC / AC power conversion; the first end of the stator winding of the corresponding motor is connected to the corresponding branch on the AC side of the at least one of the first power converter and the second power converter.

[0029] According to one implementation of the first aspect, at least one of the first power converter and the second power converter is used to perform AC / DC power conversion; the first end of the stator winding of the corresponding motor is connected to the corresponding branch on the AC side of the at least one of the first power converter and the second power converter.

[0030] These alternative configurations enhance customizability for a wide range of EV needs.

[0031] According to one implementation of the first aspect, at least one of the first power converter and the second power converter includes a parallel connection of three independently controlled half-bridges, the half-bridges providing the respective branches of the at least one of the first power converter and the second power converter.

[0032] This configuration enables the modular, multi-unit architecture of the power converter.

[0033] According to one implementation of the first aspect, at least one of the first power converter and the second power converter includes a parallel connection of three independently controlled two-level (2L) half-bridges.

[0034] This configuration, based on a 2L half-bridge that provides two DC voltage levels, implies low complexity.

[0035] According to one implementation of the first aspect, at least one of the first power converter and the second power converter includes three independently controlled n-level (nL) half-bridges connected in parallel, wherein the number of levels n exceeds 2.

[0036] This configuration, based on an nL half-bridge that provides an additional DC voltage level, reduces losses and stress on the switching devices, making it particularly suitable for high-voltage applications.

[0037] According to one implementation of the first aspect, the device can be connected to the power grid interface, the power grid interface including an electromagnetic interference (EMI) filter and a full-pole gate cutoff switch, the full-pole gate cutoff switch providing the branch of the power grid interface.

[0038] This configuration improves EMI suppression and operational safety in EV charging mode.

[0039] According to one implementation of the first aspect, at least one of the first motor and the second motor includes an induction motor or a permanent magnet synchronous motor.

[0040] The asynchronous (or induction) motor used in this article can refer to an AC drive motor, wherein the current required to generate torque in the rotor is obtained through electromagnetic induction in the magnetic field of the stator windings. In other words, the rotational speed of the induction motor must be slightly slower than that of the AC cycle in order to induce current in the rotor windings.

[0041] The synchronous motor used in this article can refer to an AC drive motor, in which the rotation of the rotor is synchronized with the frequency of the supply current, and the rotation period is exactly an integer equal to the AC cycle. In other words, the synchronous motor rotates at a speed locked to the line frequency. Permanent magnet synchronous motors use permanent magnets embedded in the rotor to generate a constant magnetic field.

[0042] These configurations enhance customizability for various EV needs.

[0043] A second aspect of the present invention provides a system comprising: an apparatus according to the first aspect or any embodiment thereof; a power grid interface connected to a first motor and a second motor of the apparatus; an energy storage device interface connected to a first power converter and a second power converter of the apparatus; and an energy storage device connected to the energy storage device interface.

[0044] The system is capable of charging the EV's energy storage device (e.g., a battery) from the power grid, using the stored power to generate torque, and even returning the stored power to the power grid when needed.

[0045] A third aspect of the present invention provides a method for operating a power conversion and dual-electric drive device. The device includes: a first power converter and a second power converter, each including three output branches; a first motor and a second motor, each including three open-end stator windings, the three open-end stator windings each having a first end and a second end; a first power switch and a second power switch; the second ends of the stator windings of the first motor are connected together and have the same potential; the second ends of the stator windings of the second motor are connected together and have the same potential. The method includes: connecting the first end of the stator winding of the first motor to a corresponding branch of the three branches of the first power converter; connecting the first end of the stator winding of the second motor to a corresponding branch of the three branches of the second power converter; selectively disconnecting at most one second end of the second end of the stator winding of the first motor from all other second ends using the first power switch to establish at most two different potentials; and selectively disconnecting at most one second end of the second end of the stator winding of the second motor from all other second ends using the second power switch to establish at most two other different potentials.

[0046] This allows EVs to achieve a charging mode that integrates with a three-phase power grid without generating any torque, and utilizes all existing power electronics in the traction system and motor inductance. Therefore, it saves space and improves power density, efficiency, and reliability.

[0047] According to one implementation of the third aspect, the method includes: utilizing the apparatus described in the first aspect or any embodiment thereof.

[0048] Therefore, by analogy, the aforementioned device features and related advantages also apply to the method described according to the third aspect.

[0049] A fourth aspect of the invention provides a computer program comprising program code for performing, when implemented on a processor of the apparatus according to the first aspect or any embodiment thereof, the method according to the third aspect or any embodiment thereof.

[0050] It should be noted that all devices, elements, units, and apparatuses described in this invention can be implemented as software or hardware elements or any combination thereof. All steps performed by the various entities described in this application and the functions described as being performed by the various entities are intended to indicate that the respective entities are used to perform the corresponding steps and functions. Although the specific functions or steps performed by external entities are not reflected in the detailed description of the specific elements of the entities performing the specific steps or functions in the following detailed description of specific embodiments, those skilled in the art will understand that these methods and functions can be implemented by corresponding hardware or software elements or any combination thereof. Attached Figure Description

[0051] The above aspects will be set forth in the following description of various embodiments, taken in conjunction with the accompanying drawings, wherein:

[0052] Figure 1 illustrates an exemplary EV architecture with dual-motor drive;

[0053] Figure 2 An example of the apparatus provided by the present invention is shown;

[0054] Figure 3 An apparatus for generating torque (i.e., driving) provided by an example of the present invention is shown;

[0055] Figures 4 to 6 The apparatus for single-phase charging provided by various examples of the present invention is shown;

[0056] Figure 7 An apparatus for three-phase charging provided by an example of the present invention is shown;

[0057] Figure 8 An apparatus including an AC / AC power converter is shown as an example of the present invention;

[0058] Figure 9 An example of the present invention is shown, comprising an AC / DC power converter, device 2;

[0059] Figure 10 The overall scheme of the power converter of the device provided in the example of the present invention is shown;

[0060] Figure 11 A general scheme for a power grid interface that can be connected to the device provided in the example of the present invention is shown;

[0061] Figure 12 A flowchart of a method of operating the apparatus provided in this invention is shown. Detailed Implementation

[0062] The above aspects will now be described in conjunction with the embodiments shown in the accompanying drawings.

[0063] Unless otherwise stated, the features of these embodiments can be combined with each other.

[0064] The accompanying drawings should be considered as schematic illustrations, and the elements shown are not necessarily shown to scale. Rather, the various elements are shown so that their function and general purpose will be obvious to those skilled in the art.

[0065] Figure 1 illustrates an exemplary EV architecture with dual-motor drive.

[0066] In the charging mode of EV architecture 1, the three-phase AC input terminal 101 feeds power to the on-board charger 102, which in turn supplies power to the high-voltage power system battery 103, and the power is temporarily stored in the high-voltage power system battery 103.

[0067] In the traction mode of the EV architecture 1, the three-phase inverter 104 uses the electrical energy stored in the power system battery 103 to power the corresponding motor 105, and the corresponding motor 105 converts the electrical energy into torque applied to the EV drive shaft.

[0068] In both charging and traction modes, the auxiliary power module (APM) 106 uses the electrical energy stored in the power system battery 103 to convert high voltage down to low voltage (e.g., 12V) and provides the power to a low-voltage auxiliary battery 107 that temporarily stores the power. The control unit 108 of the EV's power system uses the electrical energy stored in the auxiliary battery 107 to ensure its operation.

[0069] The EV architecture shown in Figure 1 relies on physically separate charging and traction functions (104, 105). The charging function 102 is always an onboard function, requires dedicated space, needs to be placed inside the vehicle when it is in motion, and cannot provide any additional functions.

[0070] As described below, the present invention aims to combine the charging function and the traction function, without considering single-phase or three-phase charging operation.

[0071] Figure 2 The apparatus 2 provided by the present invention is shown as an example.

[0072] The device 2 is suitable for power conversion and dual electric drive, and includes: a first power converter 201, including three branches 202; and a second power converter 203, including three branches 204.

[0073] At least one of the first power converter 201 and the second power converter 203 can be used to adjust the electrical parameters on the demand side of the at least one of the first power converter 201 and the second power converter 203.

[0074] The device 2 further includes: a first motor 205, comprising three open-end stator windings 206, the three open-end stator windings 206 having a first end and a second end (labeled as 'a', 'b', and 'c'); and a second motor 207, comprising three open-end stator windings 208, the three open-end stator windings 208 having a first end and a second end (also labeled as 'a', 'b', and 'c').

[0075] At least one of the first motor 205 and the second motor 207 may include an induction motor or a permanent magnet synchronous motor.

[0076] The first end of the stator winding 206 of the first motor 205 is connected to a corresponding branch of the three branches 202 of the first power converter 201. Similarly, the first end of the stator winding 208 of the second motor 207 is connected to a corresponding branch of the three branches 204 of the second power converter 203. The second ends ('a', 'b', 'c') of the stator winding 206 of the first motor 205 are connected together and have the same potential. Likewise, the second ends ('a', 'b', 'c') of the stator winding 208 of the second motor 207 are connected together and have the same potential.

[0077] The device 2 further includes a first power switch (209, 'S1') and a second power switch (210, 'S2'). The first power switch (209, 'S1') is used to selectively disconnect one of the second terminals ('a', 'b', 'c') of the stator winding 206 of the first motor 205 (i.e., 'a') from all the other second terminals (i.e., 'b', 'c') to establish up to two different potentials. Similarly, the second power switch (210, 'S2') is used to selectively disconnect one of the second terminals ('a', 'b', 'c') of the stator winding 208 of the second motor 207 (i.e., 'a') from all the other second terminals (i.e., 'b', 'c') to establish up to two different other potentials.

[0078] The device 2 may also include a third power switch (211, 'S3') for selectively combining the two potentials of the established different potentials, the two potentials relating to the majority of the stator windings 206 of the first motor 205 and the minority of the stator windings 208 of the second motor 207.

[0079] Typically, the connectivity between the branches (213, 'A', 'B', 'C') of the power grid interface 212 and the second terminals ('a', 'b', 'c') of the stator windings (206, 208) of the first motor 205 and the second motor 207 can be represented by the switching states of the first power switch (209, 'S1'), the second power switch (210, 'S2'), and (where applicable) the third power switch (211, 'S3') as follows:

[0080] Table I—Connectivity between power grid interface 212 (branch A, B, C) and motors 205 and 207 (stator winding terminals a, b, c)

[0081]

[0082] For example, if all the power switches are in the closed / conducted / open state (i.e., S1=S2=S3=1), the branch 'A' of the power grid interface 212 is connected to the second terminal 'b' of the second motor 207.

[0083] Charging the energy storage device 216 from the power grid 214 requires the formation of a system, which includes: a power conversion and dual electric drive device 2 as described above; a power grid interface 212 connected to a first motor 205 and a second motor 207 of the device 2; an energy storage device interface 215 connected to the first power converter 201 and the second power converter 203 of the device 2; and an energy storage device 216 connected to the energy storage device interface 215.

[0084] Figure 2 The device 2 shown can replace the corresponding device shown in FIG1, which includes the on-board charger 102, the power system battery 103, the three-phase inverter 104 and the motor 105.

[0085] Figure 1 and Figure 2 The comparison shows that the on-board charger 102 shown in Figure 1 is integrated into the motor (205, 207).

[0086] The device 2 is capable of charging the energy storage device 216 (e.g., battery) of the EV from the power grid 214, using the stored power to generate torque, and even returning the stored power to the power grid when needed.

[0087] Figure 3 A device 2 for generating torque (i.e., driving) is shown as an example of the present invention.

[0088] The generation of torque / drive requires the second ends ('a', 'b', 'c') of the stator windings 206 of the first motor 205 to be connected to each other to form a star structure, and the second ends ('a', 'b', 'c') of the stator windings 208 of the second motor 207 to be connected to each other to form a star structure, and the two star structures are isolated from each other, as shown below:

[0089] The first power switch (209, 'S1') can be used to keep the second terminals ('a', 'b', 'c') of the stator winding 206 of the first motor 205 from being disconnected from each other in order to establish a single distinct potential.

[0090] The second power switch (210, 'S2') can be used to keep the second terminals ('a', 'b', 'c') of the stator winding 208 of the second motor 207 from being disconnected from each other in order to establish a single, different potential.

[0091] The third power switch (211, 'S3') can be used to avoid combining any of the different potentials that have been established.

[0092] In other words, such as Figure 3 As shown, the first power switch (209, 'S1') can be in a closed / conducting / open state (i.e., S1 = 1), the second power switch (210, 'S2') can also be in a closed / conducting / open state (i.e., S2 = 1), and the third power switch (211, 'S3') can be in an open / non-conducting / closed state (i.e., S3 = 0).

[0093] Referring to Table I as defined above, the results show that the connectivity between the branches (213, 'A', 'B', 'C') of the power grid interface 212 and the second terminals ('a', 'b', 'c') of the stator windings (206, 208) of the corresponding motors (205, 207) can be represented by the above combination of the switching states of the first power switch (209, 'S1'), the second power switch (210, 'S2'), and the third power switch (211, 'S3'):

[0094] Table II—Possible combinations of switching states S1, S2, and S3 that allow torque / drive generation

[0095]

[0096] The lack of connection between the grid interface 212 and the motors (205, 207) obviously prevents charging, and the electrical energy from the energy storage device 216 can be used to generate torque / drive.

[0097] Regarding the generation of torque / drive, at least one of the first power converter 201 and the second power converter 203 can be used to operate according to a direct torque control (DTC), field-oriented control (FOC), model predictive control (MPC), or open-loop control strategy, and can be used to adjust the torque of the corresponding motor according to the corresponding torque reference.

[0098] Figures 4 to 6 A device 2 for single-phase charging is shown, according to various examples of the present invention.

[0099] For single-phase charging, the established different potentials are connected to two of the three branches (213, 'A', 'B', 'C') of the single-phase grid interface 212, which can be connected to the device 2.

[0100] Clearly, choosing two of the three branches will result in three permutations, each represented by a separate graph.

[0101] Figure 4 Device 2 is shown, wherein the established different potentials are connected to two branches ('A' and 'C') of the branches (213, 'A', 'B', 'C') of the power grid interface 212.

[0102] Referring to Table I as defined above, the connectivity between the branch (213, 'A', 'C') of the power grid interface 212 and the second terminals ('a', 'b', 'c') of the stator windings (206, 208) of the corresponding motors (205, 207) can be represented as follows, based on a combination of the switching states of the first power switch (209, 'S1'), the second power switch (210, 'S2'), and the third power switch (211, 'S3'):

[0103] Table III—Possible combinations of switch states S1, S2, and S3 that allow single-phase charging via grid interface branches A and C

[0104]

[0105] For example, given a combination of S1=1, S2=0 and S3=0 (or 1), all the second ends ('a', 'b', 'c') of the stator winding 206 of the first motor 205 are connected to the power grid interface branch 'A', and the second ends ('b', 'c') of the stator winding 208 of the second motor 207 are connected to the power grid interface branch 'C'.

[0106] Figure 5 Device 2 is shown, wherein the established different potentials are connected to two branches ('B' and 'C') of the branches (213, 'A', 'B', 'C') of the power grid interface 212.

[0107] Referring to Table I as defined above, the connectivity between the branch (213, 'B', 'C') of the power grid interface 212 and the second terminals ('a', 'b', 'c') of the stator windings (206, 208) of the corresponding motors (205, 207) can be represented as follows, based on a combination of the switching states of the first power switch (209, 'S1'), the second power switch (210, 'S2'), and the third power switch (211, 'S3'):

[0108] Table IV—Possible combinations of switch states S1, S2, and S3 that allow single-phase charging via grid interface branches B and C

[0109]

[0110] For example, given a combination of S1=1, S2=0 and S3=0 (or 1), all the second ends ('a', 'b', 'c') of the stator winding 206 of the first motor 205 are connected to the power grid interface branch 'B', and the second ends ('b', 'c') of the stator winding 208 of the second motor 207 are connected to the power grid interface branch 'C'.

[0111] Figure 6 Device 2 is shown, wherein the established different potentials are connected to two branches ('A' and 'B') of the branches (213, 'A', 'B', 'C') of the power grid interface 212.

[0112] Referring to Table I as defined above, the connectivity between the branch (213, 'A', 'B') of the power grid interface 212 and the second terminals ('a', 'b', 'c') of the stator windings (206, 208) of the corresponding motors (205, 207) can be represented as follows based on a combination of the switching states of the first power switch (209, 'S1'), the second power switch (210, 'S2'), and the third power switch (211, 'S3'):

[0113] Table V—Possible combinations of switch states S1, S2, and S3 that allow single-phase charging via grid interface branches A and B.

[0114]

[0115] For example, given a combination of S1=0, S2=1, and S3=0 (or 1), all the second ends ('b', 'c') of the stator winding 206 of the first motor 205 are connected to the power grid interface branch 'B', and all the second ends of the stator winding 208 of the second motor 207 are not connected to any of the power grid interface branches, or are connected to the power grid interface branch 'B' (depending on the switching state of the third power switch (211, 'S3')).

[0116] Typically, each combination of switching states listed in Tables III, IV, and V above ensures that at least two of the three stator windings (206, 208) of the respective motors (205, 207) (corresponding to the different potentials established above) are connected to the same power grid interface branch 213. In the tables, the second terminals of the respective motors (205, 207) having the same potential are indicated by shaded portions.

[0117] Placing the multiple second terminals of the respective motors (205, 207) at the same potential prevents the motors (205, 207) from generating torque / drive, while providing a continuous power transmission path for charging the energy storage device 216 from the power grid 214.

[0118] Figure 7 An example of the present invention is shown, which is a device 2 for three-phase charging.

[0119] For three-phase charging, the established different potentials are connected to the three corresponding branches (213, 'A', 'B', 'C') of the three-phase grid interface 212, which can be connected to the device 2 as follows:

[0120] The first power switch (209, 'S1') can be used to disconnect one of the second terminals ('a', 'b', 'c') of the stator winding 206 of the first motor 205 (i.e., second terminal 'a') from all the other second terminals (i.e., second terminals 'b', 'c') of the second terminals ('a', 'b', 'c') to establish up to two different potentials.

[0121] The second power switch (210, 'S2') can be used to disconnect one of the second terminals ('a', 'b', 'c') of the second terminal ('a', 'b', 'c') of the stator winding 208 of the second motor 207 from all the other second terminals ('b', 'c') to establish up to two different other potentials.

[0122] The third power switch (211, 'S3') can be used to combine the two potentials of the established different potentials, which involve the majority of the stator windings 206 of the first motor 205 (i.e., the second terminals 'b', 'c') and the minority of the stator windings 208 of the second motor 207 (i.e., the second terminal 'a').

[0123] In other words, such as Figure 7 As shown, the first power switch (209, 'S1') can be in an open / non-conducting / closed state (i.e., S1 = 0), the second power switch (210, 'S2') can also be in an open / non-conducting / closed state (i.e., S2 = 0), and the third power switch (211, 'S3') can be in a closed / conducting / open state (i.e., S3 = 1).

[0124] Therefore, referring to Table I as defined above, the connectivity between the branch (213, 'A', 'B', 'C') of the power grid interface 212 and the second terminals ('a', 'b', 'c') of the stator windings (206, 208) of the corresponding motors (205, 207) can be represented by a single combination of the switching states of the first power switch (209, 'S1'), the second power switch (210, 'S2'), and the third power switch (211, 'S3') as follows:

[0125] Table VI—Possible combinations of switch states S1, S2, and S3 that allow three-phase charging via grid interface branches A, B, and C

[0126]

[0127] The combination of switching states described in Table VI above ensures that at least two of the three stator windings (206, 208) of the respective motors (205, 207) (corresponding to the different potentials established above) are connected to the same power grid interface branch 213. In the table, the second terminals of the respective motors (205, 207) having the same potential are indicated by shaded portions.

[0128] Placing the multiple second terminals of the respective motors (205, 207) at the same potential prevents the motors (205, 207) from generating torque / drive, while providing a continuous power transmission path for charging the energy storage device 216 from the power grid 214.

[0129] Figure 8 An example of the present invention is shown, comprising an AC / AC power converter, device 2.

[0130] At least one of the first power converter 201 and the second power converter 203 can be used to perform AC / AC power conversion. For this purpose, the first end of the stator winding (206, 208) of the respective motor (205, 207) can be connected to the respective branch (202, 204) on the AC side of at least one of the first power converter 201 and the second power converter 203.

[0131] like Figure 8 As shown, energy storage device interface 215 can be connected to the first AC / AC power converter 201 and the second AC / AC power converter 203, and energy storage device 216 can be connected to energy storage device interface 216. Since energy storage device 216 is a DC device, such as a high-voltage power system battery, energy storage device interface 215 is used for mediation between energy storage device 216 and the first AC / AC power converter 201 and the second AC / AC power converter 203. In other words, energy storage device interface 215 can be an AC / DC device, such as... Figure 8 As shown.

[0132] Figure 9 An example of the present invention is shown, comprising an AC / DC power converter, device 2.

[0133] Figure 9 The device 2 shown corresponds to Figure 8 The embodiment shown differs in that, Figure 9In the illustrated device 2, at least one of the first power converter 201 and the second power converter 203 can be used to perform AC / DC power conversion. For this purpose, the first end of the stator winding (206, 208) of the respective motor can be connected to the corresponding branch (202, 204) on the AC side of at least one of the first power converter 201 and the second power converter 203.

[0134] exist Figure 9 In the illustrated embodiment, the energy storage device interface 215 is used for mediation between the energy storage device 216, which is a DC device, and the DC side of the first AC / DC power converter 201 and the second AC / DC power converter 203. In other words, the energy storage device interface 215 is a DC / DC device, such as... Figure 9 As shown.

[0135] If the energy storage device 216 is matched with the first AC / DC power converter 201 and the second AC / DC power converter 203 in terms of DC voltage, the energy storage device interface 215 can be omitted.

[0136] Figure 8 and Figure 9 The configuration shown enhances customizability for various EV needs.

[0137] Figure 10 The overall scheme of the power converter (201, 203) of the device 2 provided in the example of the present invention is shown.

[0138] Figure 10 At least one of the first power converter 201 and the second power converter 203, as schematically suggested below, may include a parallel connection (on the same track) of at least three independently controlled half-bridges 1001. These half-bridges 1001 present / provide the respective branches (202, 204) of at least one of the first power converter 201 and the second power converter 203.

[0139] For example, at least one of the first power converter 201 and the second power converter 203 may include a parallel connection of three independently controlled two-level (2L) half-bridges 1001A, such as... Figure 10 The left side of the middle section is shown. This type of 2L half-bridge 1001A may include a series connection of a power switch with a center tap.

[0140] This 2L half-bridge-based configuration is used to alternate between two levels of DC voltage, such as +V. DC / 2 and -V DC / 2, which means low circuit complexity. The 2L half-bridge is particularly suitable for medium voltage applications.

[0141] Alternatively, at least one of the first power converter 201 and the second power converter 203 may include a parallel connection of three independently controlled n-level (nL) half-bridges (1001B to 1001D), wherein the number of n-level DC voltages exceeds 2. Figure 10 The right side of the middle section shows various three-level (3L) half-bridges (1001B to 1001D).

[0142] This 3L half-bridge-based configuration is used to alternate between three levels of DC voltage, such as +V. DC / 2, 0 and -V DC / 2. The additional zero-voltage level reduces losses and stress on the switching devices. Therefore, the 3L half-bridge is particularly suitable for high-voltage applications.

[0143] As a first example, the 3L Neutral Point Clamped (NPC) half-bridge 1001B may include the aforementioned 2L half-bridge, which is connected in parallel to a series connection of diodes for clamping the midpoint, wherein the parallel connection is closed in series by an additional power switch.

[0144] As a second example, the 3L Active Neutral Point Clamped (ANPC) half-bridge 1001C may include two 2L half-bridges connected in parallel as described above, wherein the parallel connection is closed in series by an additional power switch.

[0145] This configuration based on the 3L-ANPC half-bridge 1001C can "force" switching losses on specific power switches of the half-bridge, which improves overall efficiency.

[0146] As a third example, the 3L flying capacitor (FC) half-bridge 1001D may include the aforementioned 2L half-bridge connected in parallel to the flying capacitor, wherein the parallel connection is closed in series by an additional power switch.

[0147] Specifically, for all three-level configurations, the number of levels n can be extended from 3 to N.

[0148] Each of the aforementioned independently controlled half-bridges 1001 can be composed of independently controlled half-bridges connected in parallel (the purpose of which is to shunt the output current of the half-bridges 1001).

[0149] Figure 10The upper part indicates that the power switch forming the half-bridge 1001 may include an insulated gate bipolar transistor (IGBT) or a field effect transistor (FET).

[0150] Figure 11 An overall scheme is shown that can be connected to the power grid interface 212 of the device 2 provided in the example of the present invention.

[0151] Figure 11 The device 2 shown can be connected to the power grid interface 212, which preferably includes an electromagnetic interference (EMI) filter 1101 and a full-pole gate cutoff switch 1102, which presents / provides the branch 213 of the power grid interface 212.

[0152] This configuration improves EMI suppression and operational safety in EV charging mode.

[0153] Figure 12 A flowchart of method 12 of the operating device 2 provided in the example of the present invention is shown.

[0154] The method 12 is used to operate a power conversion and dual electric drive device 2, the device 2 including: a first power converter 201 and a second power converter 203; a first motor 205 and a second motor 207; a first power switch (209, 'S1') and a second power switch (210, 'S2').

[0155] The first power converter 201 and the second power converter 203 each include three branches (202, 204). The first motor 205 and the second motor 207 each include three open-end stator windings (206, 208), and the three open-end stator windings (206, 208) each have a first end and a second end (denoted as 'a', 'b', 'c').

[0156] The second ends ('a', 'b', 'c') of the stator winding 206 of the first motor 205 are connected together and have the same potential. Similarly, the second ends ('a', 'b', 'c') of the stator winding 208 of the second motor 207 are connected together and have the same potential.

[0157] The method 12 includes the steps of connecting (1201), connecting (1202), selectively disconnecting (1203), and selectively disconnecting (1204):

[0158] The first step involves connecting (1201) the first end of the stator winding 206 of the first motor 205 to a corresponding branch of the three branches 202 of the first power converter 201.

[0159] The second step involves connecting (1202) the first end of the stator winding 208 of the second motor 207 to a corresponding branch of the three branches 204 of the second power converter 203.

[0160] The third step involves using the first power switch (209, S1) to selectively disconnect (1203) at most one of the second terminals ('a', 'b', 'c') of the stator winding 206 of the first motor 205 from all the other second terminals ('a', 'b', 'c') to establish at most two different potentials.

[0161] The fourth step involves using the second power switch (210, S2) to selectively disconnect (1204) at most one of the second terminals ('a', 'b', 'c') of the stator winding 208 of the second motor 207 from all the other second terminals ('a', 'b', 'c') to establish at most two different other potentials.

[0162] This allows EVs to achieve a charging mode that integrates with a three-phase power grid without generating any torque, and utilizes all existing power electronics in the traction system and motor inductance. Therefore, it saves space and improves power density, efficiency, and reliability.

[0163] Preferably, the method 12 includes using the apparatus 2 according to the first aspect or any embodiment thereof.

[0164] Therefore, by analogy, the aforementioned features and related advantages of the device 2 are also applicable to the method 12 according to the third aspect.

[0165] The processor or processing circuit of the device 2 may include hardware and / or the processing circuit may be controlled by software. The hardware may include analog circuits or digital circuits, or both analog and digital circuits. The digital circuit may include components such as application-specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), adaptive compute acceleration platforms (ACAPs), digital signal processors (DSPs), or multi-functional processors.

[0166] The device 2 may further include storage circuitry storing one or more instructions that can be executed by a processor or processing circuitry (specifically, under software control). For example, the storage circuitry may include a computer program (not shown) comprising program code for executing the method 12 according to the third aspect of the invention, when implemented on a processor of the device 2 according to the first aspect or any embodiment thereof.

[0167] This invention has been described primarily in conjunction with various embodiments and implementations as examples. However, based on a study of the drawings, the invention, and the independent claims, those skilled in the art will be able to understand and implement other variations when practicing the claimed invention. In the claims and description, the word "comprising" does not exclude other elements or steps, and the quantifier "a" does not exclude a plurality. A single element or other unit may fulfill the function of several entities or items listed in the claims. Listing measures in dissimilar dependent claims does not imply that combinations of these measures cannot be used in advantageous implementations.

Claims

1. A power conversion and dual-electric drive device (2), characterized in that, The device (2) includes: The first power converter (201) and the second power converter (203) each include three branches (202, 204). The first motor (205) and the second motor (207) each include three open-end stator windings (206, 208), and the three open-end stator windings (206, 208) each have a first end and a second end (a, b, c). First power switch (209, S1), second power switch (210, S2) and third power switch (211, S3). The first end of the stator winding (206) of the first motor (205) is connected to the corresponding branch of the three branches (202) of the first power converter (201); The first end of the stator winding (208) of the second motor (207) is connected to the corresponding branch of the three branches (204) of the second power converter (203); The second ends (a, b, c) of the stator windings (206) of the first motor (205) are connected together and have the same potential; The second ends (a, b, c) of the stator windings (208) of the second motor (207) are connected together and have the same potential; The first power switch (209, S1) is used to selectively disconnect one of the second terminals (a, b, c) of the stator winding (206) of the first motor (205) from all the other second terminals (b, c) of the second terminal (a, b, c) to establish up to two different potentials. The first power switch (209, S1) is also used to prevent the second terminals (a, b, c) of the stator winding (206) of the first motor (205) from being disconnected from each other to establish a single different potential. The second power switch (210, S2) is used to selectively disconnect one of the second terminals (a, b, c) of the stator winding (208) of the second motor (207) from all the other second terminals (b, c) of the second terminal (a, b, c) to establish up to two different other potentials. The second power switch (210, S2) is also used to prevent the second terminals (a, b, c) of the stator winding (208) of the second motor (207) from being disconnected from each other to establish a single different other potential. The third power switch (211, S3) is used to selectively combine two of the established different potentials, which involve the majority of the stator windings (206) of the first motor (205) and the minority of the stator windings (208) of the second motor (207). The third power switch (211, S3) is also used not to combine any of the established different potentials.

2. The apparatus (2) according to claim 1, characterized in that, The established different potentials can be connected to two corresponding branches (213, A, B, C) of the power grid interface (212), which can be connected to the device (2). The power grid interface (212) is a single-phase power grid interface.

3. The device (2) according to claim 1, characterized in that, The first power switch (209, S1) is used to disconnect one of the second terminals (a, b, c) of the stator winding (206) of the first motor (205) from all the other second terminals (b, c) to establish a maximum of two different potentials; The second power switch (210, S2) is used to disconnect one of the second terminals (a, b, c) of the second terminal (a) of the stator winding (208) of the second motor (207) from all the other second terminals (b, c) of the second terminal (a, b, c) to establish up to two different other potentials; The third power switch (211, S3) is used to combine the two potentials of the established different potentials, which involve the majority (b, c) of the stator windings (206) of the first motor (205) and the fewest (a) of the stator windings (208) of the second motor (207). The established different potentials can be connected to three corresponding branches (213, A, B, C) of the power grid interface (212), which can be connected to the device (2), and the power grid interface (212) is a three-phase power grid interface.

4. The apparatus (2) according to claim 2 or 3, characterized in that, At least one of the first power converter (201) and the second power converter (203) is used to operate according to a direct torque control (DTC), field-oriented control (FOC), model predictive control (MPC) or open-loop control strategy, and is used to adjust the torque of the corresponding motor according to the corresponding torque reference.

5. The apparatus (2) according to any one of claims 1 to 3, characterized in that, At least one of the first power converter (201) and the second power converter (203) is used to adjust the electrical parameters on the demand side of at least one of the first power converter (201) and the second power converter (203).

6. The apparatus (2) according to any one of claims 1 to 3, characterized in that, At least one of the first power converter (201) and the second power converter (203) is used to perform AC / AC power conversion; The first end of the stator winding (206, 208) of the corresponding motor is connected to the corresponding branch (202, 204) on the AC side of at least one of the first power converter (201) and the second power converter (203).

7. The apparatus (2) according to any one of claims 1 to 3, characterized in that, At least one of the first power converter (201) and the second power converter (203) is used to perform AC / DC power conversion; The first end of the stator winding (206, 208) of the corresponding motor is connected to the corresponding branch (202, 204) on the AC side of at least one of the first power converter (201) and the second power converter (203).

8. The apparatus (2) according to any one of claims 1 to 3, characterized in that, At least one of the first power converter (201) and the second power converter (203) includes a parallel connection of three independently controlled half-bridges (1001), which provide the respective branch (202, 204) of at least one of the first power converter (201) and the second power converter (203).

9. The apparatus (2) according to claim 8, characterized in that, At least one of the first power converter (201) and the second power converter (203) includes three independently controlled two-level ( two -level, 2 L) Parallel connection of half-bridge (1001A).

10. The apparatus (2) according to claim 8, characterized in that, At least one of the first power converter (201) and the second power converter (203) includes three independently controlled [functions / systems]. n Level ( n -level, n L) Parallel connection of half-bridge (1001B to 1001D), wherein the number of levels n More than 2.

11. The apparatus (2) according to claim 1, characterized in that, The device (2) can be connected to a power grid interface (212), which includes an electromagnetic interference (EMI) filter (1101) and a full-pole gate cutoff switch (1102), the full-pole gate cutoff switch (1102) providing the branch of the power grid interface (212).

12. The apparatus (2) according to any one of claims 1 to 3, characterized in that, At least one of the first motor (205) and the second motor (207) includes an induction motor or a permanent magnet synchronous motor.

13. A power conversion system, characterized in that, include: The apparatus (2) according to any one of claims 1 to 12; The power grid interface (212) is connected to the first motor (205) and the second motor (207) of the device (2); The energy storage device interface (215) is connected to the first power converter (201) and the second power converter (203) of the device (2). An energy storage device (216) is connected to the energy storage device interface (215).

14. A method (12) for operating a power conversion and dual electric drive device (2), characterized in that, The device (2) includes: The first power converter (201) and the second power converter (203) each include three branches (202, 204). The first motor (205) and the second motor (207) each include three open-end stator windings (206, 208), the three open-end stator windings (206, 208) each having a first end and a second end; First power switch (209, S1), second power switch (210, S2) and third power switch (211, S3). The second ends (a, b, c) of the stator windings (206) of the first motor (205) are connected together and have the same potential; The second ends (a, b, c) of the stator windings (208) of the second motor (207) are connected together and have the same potential; The method (12) includes: Connect (1201) the first end of the stator winding (206) of the first motor (205) to the corresponding branch of the three branches (202) of the first power converter (201); Connect (1202) the first end of the stator winding (208) of the second motor (207) to the corresponding branch of the three branches (204) of the second power converter (203); Using the first power switch (209, S1), at most one of the second terminals (a, b, c) of the stator winding (206) of the first motor (205) is selectively disconnected (1203) from all other second terminals (a, b, c) to establish at most two different potentials. The first power switch (209, S1) is also used to prevent the second terminals (a, b, c) of the stator winding (206) of the first motor (205) from being disconnected from each other to establish a single different potential. Using the second power switch (210, S2), at most one of the second terminals (a, b, c) of the stator winding (208) of the second motor (207) is disconnected (1204) from all other second terminals (a, b, c) to establish at most two different other potentials. The second power switch (210, S2) is also used to prevent the second terminals (a, b, c) of the stator winding (208) of the second motor (207) from being disconnected from each other to establish a single different other potential. The third power switch (211, S3) is used to selectively combine two of the established different potentials, which involve the majority of the stator windings (206) of the first motor (205) and the minority of the stator windings (208) of the second motor (207). The third power switch (211, S3) is also used not to combine any of the established different potentials.

15. The method (12) according to claim 14, characterized in that, include: Using the apparatus (2) according to any one of claims 1 to 12.

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