Motor drive system

Abstract

The present disclosure relates to a motor drive system including: a first motor and a second motor including a plurality of first windings and a plurality of second windings; a first inverter including DC terminals connected to a DC voltage source and AC terminals connected to the plurality of first windings; a first switching section including a plurality of first mode conversion switches connected to the plurality of first windings; a second inverter including DC terminals connected to the DC voltage source and AC terminals connected to the plurality of first mode conversion switches; a second switching section including a plurality of second mode conversion switches connected to the AC terminals of the second inverter and the plurality of second windings; a third switching section including a plurality of third mode conversion switches connected to the plurality of first windings; and a controller configured to control short-circuit / open-circuit states of the plurality of first mode conversion switches, the second mode conversion switches, and the third mode conversion switches based on whether the first motor and the second motor are driven.

Description

Technical Field

[0001] This disclosure relates to a motor drive device, and more specifically, to a motor drive system capable of driving two or more motors in various ways according to the required motor output. Background Technology

[0002] Typically, the first end of the windings of each phase included in the motor is connected to the inverter, and the second end is connected to each other, thus forming a Y-connection.

[0003] When the motor is driven, the switching elements inside the inverter are turned on / off via pulse width modulation, and the line voltage is applied to the Y-connected motor windings to generate AC current, thereby producing torque.

[0004] The fuel efficiency (or electrical efficiency) of environmentally friendly vehicles that use the torque generated by a motor as power (e.g., electric vehicles) depends on the inverter-motor power conversion efficiency, and maximizing both inverter power conversion efficiency and motor efficiency is crucial for improving fuel efficiency.

[0005] The efficiency of an inverter-motor system largely depends on the inverter's voltage utilization rate. When a vehicle drive point voltage utilization rate, determined by the relationship between motor speed and torque, is achieved within a high voltage utilization range, the vehicle's fuel efficiency can be improved.

[0006] However, when increasing the number of motor windings to increase maximum motor torque, the range with high voltage utilization becomes further away from the low torque region (the vehicle's main drive point), thus reducing fuel efficiency. When fuel efficiency is taken into account, the maximum motor torque may be limited if the high voltage utilization range includes the main drive point, thereby reducing vehicle acceleration performance.

[0007] To address this issue, an open-endwinding (OEW) motor drive technology has been proposed in the relevant technical field. Instead of short-circuiting the first end of the motor winding through a Y-connection, this technology connects two inverters to the two ends of the motor winding respectively and drives them accordingly.

[0008] The advantage of this OEW-based motor drive technology is that, compared to driving a motor with a typical Y-connection structure, it increases the phase voltage, thereby improving voltage utilization and achieving high output.

[0009] However, the problem with OEW motor drive technology is that, since two inverters drive a single motor, the power output of a single motor is limited, making this technology unsuitable for drive conditions requiring higher power.

[0010] The above description of the background technology is only for the purpose of helping to understand the background of this disclosure, and those skilled in the art should not assume that it corresponds to known related technologies.

[0011] The information disclosed in the Background section of this disclosure is intended only to enhance the understanding of the general background of this disclosure and should not be construed as an admission of prior art known to those skilled in the art or any form of implication. Summary of the Invention

[0012] The present disclosure aims to provide a motor drive system capable of driving two or more motors in various ways according to the required motor output, such that a single motor is driven, for example, in a Y-connection configuration and an open winding configuration, or each motor is driven in a Y-connection configuration.

[0013] According to one aspect, this disclosure provides a motor drive system, comprising: a first motor including a plurality of first windings respectively corresponding to a plurality of phases; a second motor including a plurality of second windings respectively corresponding to a plurality of phases, wherein the first ends of the plurality of second windings are connected to each other; a first inverter including a DC terminal connected to a DC voltage source and an AC terminal connected to the first ends of the plurality of first windings; a first switching unit including a plurality of first mode switching switches, wherein the first ends of the plurality of first mode switching switches are respectively connected to the second ends of the plurality of first windings; and a second inverter including a DC terminal connected to a DC voltage source and an AC terminal connected to the first ends of the plurality of first mode switching switches. The system includes: AC terminals of the respective second ends of the switching switches; a second switching section including a plurality of second mode switching switches, the two ends of which are connected to the AC terminals of the second inverter and the respective second ends of the plurality of second windings; a third switching section including a plurality of third mode switching switches, the first ends of which are respectively connected to the second ends of each of the plurality of first windings, and the second ends of the plurality of third mode switching switches being connected to each other; and a controller configured to control the short-circuit / open-circuit states of the plurality of first mode switching switches, the plurality of second mode switching switches, and the plurality of third mode switching switches according to the drive requests of the first motor and the second motor.

[0014] In an exemplary embodiment of this disclosure, in a mode that drives the first motor but not the second motor, the controller can adjust a plurality of first mode switching switches to a short-circuit state, adjust a plurality of second mode switching switches and a plurality of third mode switching switches to an open-circuit state, and adjust the first inverter and the second inverter respectively connected to the two ends of the first winding to drive the first motor in an open winding manner.

[0015] In an exemplary embodiment of this disclosure, in a mode that drives the first motor but not the second motor, the controller can adjust a plurality of third mode switching switches to a short-circuit state to form a Y-connection at the second ends of a plurality of first windings, and can adjust the first inverter to drive the first motor.

[0016] In an exemplary embodiment of this disclosure, the controller may adjust a plurality of first mode switching switches to an open circuit state, adjust a second mode switching switch to an open circuit state, or adjust a switching element in a second inverter to an open circuit state.

[0017] In an exemplary embodiment of this disclosure, in the mode of simultaneously driving the first motor and the second motor, the controller can adjust a plurality of third mode switching switches to a short-circuit state to form a Y-shaped connection at the second end of a plurality of first windings, and can adjust the first inverter to drive the first motor. It can also adjust a plurality of first mode switching switches to an open-circuit state, adjust the second mode switching switches to a short-circuit state, and adjust the second inverter to drive the second motor.

[0018] In an exemplary embodiment of this disclosure, the controller may receive an input of a desired output and may determine a mode for driving the first motor and the second motor based on a comparison between the desired output of the input and a predetermined first reference value and a second reference value greater than the first reference value.

[0019] In an exemplary embodiment of this disclosure, when the required output is less than or equal to a predetermined first reference value, the controller can adjust a plurality of third mode switching switches to a short-circuit state to form a Y-connection at the second end of a plurality of first windings, and can adjust the first inverter to drive the first motor.

[0020] In an exemplary embodiment of this disclosure, the controller may adjust a plurality of first mode switching switches to an open circuit state, adjust a plurality of second mode switching switches to an open circuit state, or adjust the switching elements in the second inverter to an open circuit state.

[0021] In an exemplary embodiment of this disclosure, when the required output is greater than a first reference value and less than or equal to a second reference value, the controller can adjust a plurality of first mode switching switches to a short-circuit state, adjust a plurality of second mode switching switches and a plurality of third mode switching switches to an open-circuit state, and adjust the first inverter and the second inverter respectively connected to the two ends of the first winding to drive the first motor in an open winding manner.

[0022] In an exemplary embodiment of this disclosure, when the required output is greater than the second reference value, the controller can adjust a plurality of third mode switching switches to a short-circuit state to form a Y-connection at the second end of a plurality of first windings, and can adjust the first inverter to drive the first motor. It can also adjust a plurality of first mode switching switches to an open-circuit state, adjust a plurality of second mode switching switches to a short-circuit state, and adjust the second inverter to drive the second motor.

[0023] According to the above motor drive system, when a large output is required in an open-winding motor drive system, some inverters used in open-winding systems can be applied to drive additional motors without adding a separate inverter. Therefore, the required output can be ensured simply by adding a motor without adding an inverter, thereby minimizing the increase in manufacturing costs as the output increases.

[0024] Furthermore, the motor drive system according to various embodiments of this disclosure can drive the motor in various ways that best meet the required output level, such as various options such as single motor Y-connection drive, single motor OEW drive and multi-motor drive, thereby improving the overall efficiency of the system.

[0025] The methods and apparatus of this disclosure have other features and advantages, which will be apparent from or set forth in more detail in the accompanying drawings and the following detailed description, which together serve to explain certain principles of this disclosure. Attached Figure Description

[0026] Figure 1 This is a circuit diagram illustrating a motor drive system according to exemplary embodiments of the present disclosure; and

[0027] Figure 2 and Figure 3 This is a flowchart illustrating an operational example of a motor drive system according to an exemplary embodiment of the present disclosure.

[0028] It is understood that the accompanying drawings are not necessarily drawn to scale and present a simplified representation to some extent of the various features illustrating the basic principles of this disclosure. Specific design features of this disclosure, such as specific dimensions, orientations, locations, and shapes, will be determined in part by the particular intended application and environment of use.

[0029] In the accompanying drawings, reference numerals refer to the same or equivalent parts of this disclosure in the various figures. Detailed Implementation

[0030] Reference will now be made in detail to various embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings and described below. Although the present disclosure will be described in conjunction with exemplary embodiments thereof, it will be understood that this description is not intended to limit the present disclosure to those exemplary embodiments. On the other hand, the present disclosure is intended to cover not only the exemplary embodiments thereof, but also various alternatives, modifications, equivalents and other embodiments included within the spirit and scope of the present disclosure as defined in the appended claims.

[0031] In the following, motor drive systems according to various embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0032] Figure 1 This is a circuit diagram illustrating a motor drive system according to an exemplary embodiment of the present disclosure.

[0033] Reference Figure 1 A motor drive system according to an exemplary embodiment of the present disclosure may include: a first motor 100, including a plurality of first windings L11-L13 corresponding to a plurality of phases; a second motor 200, including a plurality of second windings L21-L23 corresponding to a plurality of phases; a first inverter 10, including a DC terminal connected to a DC voltage source 300 and an AC terminal connected to each first terminal of the plurality of first windings L11-L13; a first switching unit 40, including a plurality of first mode switching switches S41-S43, the first terminals of the first mode switching switches S41-S43 being respectively connected to the second terminals of the plurality of first windings L11-L13; and a second inverter 20, including a DC terminal connected to a DC voltage source 300 and a second terminal connected to the plurality of first mode switching switches S41-S43. The AC terminals of each of the second ends; a second switching section 50, including a plurality of second mode switching switches S51-S53, the two ends of which are respectively connected to the AC terminals of the second inverter 20 and the second ends of the plurality of second windings L21-L23; a third switching section 30, including a plurality of third mode switching switches S31-S33, the third mode switching switches S31-S33 including a first end respectively connected to the second ends of the plurality of first windings L11-L13 and a second end connected to each other; and a controller 400, for controlling the short-circuit / open-circuit states of the plurality of first mode switching switches S41-S43, the plurality of second mode switching switches S51-S53 and the plurality of third mode switching switches S31-S33 based on the drive requests of the first motor 100 and the second motor 200.

[0034] The first motor 100 and the second motor 200 may each include a plurality of first windings L11-L13 and a plurality of second windings L21-L23, each winding receiving phase voltage and phase current to form a magnetic field.

[0035] The plurality of first windings L11-L13 included in the first motor 100 may include one end connected to the first inverter 10 and the other end optionally connected to the second inverter 20 or connected to each other.

[0036] The plurality of second windings L21-L23 included in the second motor 200 may include selectively connected to one end of the second inverter 20 and the other end connected to each other.

[0037] The first inverter 10 and the second inverter 20 can convert the DC power stored in the battery 300 into three-phase AC power and supply it to the first motor 100 or the second motor 200. Alternatively, during regenerative braking, they can convert the regenerative braking energy generated by the regenerative braking torque of the first motor 100 or the second motor 200 into DC power and supply it to the battery 300. This conversion between DC power and AC power can be performed by pulse width modulation control of a plurality of first switching elements S11-S16 included in the first inverter 10 and a plurality of second switching elements S21-S26 included in the second inverter 20.

[0038] The terminal portions of the first inverter 10 and the second inverter 20 connected to the battery 300 may be referred to as the DC terminals of each inverter, and the terminal portions of the first inverter 10 and the second inverter 20 connected to the first motor 100 or the second motor 200 may be referred to as the AC terminals of each inverter.

[0039] The first inverter 10 may include a plurality of legs 11-13 to which a DC voltage generated in a DC link capacitor Cdc connected between the two ends of the battery 300 is applied. The legs 11-13 may correspond to a plurality of phases of the first motor 100 respectively and form an electrical connection therebetween.

[0040] The first branch 11 of the first inverter 10 may include two switching elements S11 and S12 connected in series between the two ends of a DC capacitor Cdc to which the voltage of the battery 300 is applied, and the connection node of the two switching elements S11 and S12 may be connected to one end of a phase winding L11 in the first motor 100 so that AC power corresponding to one of the multiple phases is input or output through the connection node.

[0041] Similarly, the second branch 12 of the first inverter 10 may include two switching elements S13 and S14 connected in series between the two ends of the DC capacitor Cdc, and the connection node of the two switching elements S13 and S14 may be connected to one end of a phase winding L12 in the first motor 100 so that AC power corresponding to one of the multiple phases is input or output through the connection node.

[0042] Furthermore, the third branch 13 of the first inverter 10 may include two switching elements S15 and S16 connected in series between the two ends of the DC capacitor Cdc, and the connection node of the two switching elements S15 and S16 may be connected to one end of a phase winding L13 in the first motor 100 so that AC power corresponding to one of the multiple phases is input or output through the connection node.

[0043] The second inverter 20 may have a structure similar to that of the first inverter 10. The second inverter 20 may include a plurality of branches 21-23 to which a DC voltage generated in a DC link capacitor Cdc connected between the two ends of the battery 300 is applied. Each of the branches 21-23 may correspond to a plurality of phases of the first motor 100 and the second motor 200, and may be selectively electrically connected to either the first motor 100 or the second motor 200.

[0044] The first branch 21 of the second inverter 20 may include two switching elements S21 and S22 connected in series between the two ends of the DC capacitor Cdc, and the connection node of the two switching elements S21 and S22 may be selectively connected to the other end of a phase winding L11 in the first motor 100 or a phase winding L21 in the second motor 200, so that AC power corresponding to one of the multiple phases is input or output through the connection node.

[0045] Similarly, the second branch 22 of the second inverter 20 may include two switching elements S23 and S24 connected in series between the two ends of the DC capacitor Cdc, and the connection node of the two switching elements S23 and S24 may be selectively connected to the other end of a phase winding L12 in the first motor 100 or a phase winding L22 in the second motor 200, so that AC power corresponding to one of the multiple phases is input or output through the connection node.

[0046] Furthermore, the third branch 23 of the second inverter 20 may include two switching elements S25 and S26 connected in series between the two ends of the DC capacitor Cdc, and the connection node of the two switching elements S25 and S26 may be selectively connected to the other end of a phase winding L13 in the first motor 100 or a phase winding L23 in the second motor 200, so that AC power corresponding to one of the multiple phases is input or output through the connection node.

[0047] The first switching section 40 may include a plurality of first mode switching switches S41-S43, which are used to determine the state of electrical connection between the other end of each of the plurality of windings L11-L13 in the first inverter 10 and the AC terminal of the second inverter 20, that is, between the connection nodes of two switching elements in each of the plurality of branches 21-23 in the second inverter 20.

[0048] The short-circuit / open-circuit states of the plurality of first mode switching switches S41-S43 in the first switching unit 40 can be adjusted by the controller 400 based on the system's operating mode.

[0049] The second switching section 50 may include a plurality of second mode switching switches S51-S53, which are used to determine the state of electrical connection between one end of each of the plurality of windings L21-L23 in the second motor 200 and the AC terminal of the second inverter 20, that is, between the connection nodes of two switching elements in each of the plurality of branches 21-23 in the second inverter 20.

[0050] The short-circuit or open-circuit states of the multiple second-mode switching switches S51-S53 in the second switching unit 50 can also be adjusted by the controller 400 based on the system's operating mode.

[0051] The third switching unit 30 may include a plurality of third mode switching switches S31-S33, one end of which is connected to the other end of each of the plurality of windings L11-L13 included in the first motor 100, and the other ends of the plurality of third mode switching switches S31-S33 are connected to each other.

[0052] The short-circuit or open-circuit states of the multiple third-mode switching switches S31-S33 in the third switching section 30 can also be adjusted by the controller 400 based on the system's operating mode.

[0053] Basically, the controller 400 is a component that determines whether to drive the first motor 100 and the second motor 200 and the drive mode of their driving based on the required output of a system (e.g., a vehicle) including the first motor 100 and the second motor 200, and according to the determined drive mode, switches the open / short circuit states of the first to third mode switching switches S41-S43, S51-S53 and S31-S33 and the switching elements S11-S16 and S21-S26 included in the first inverter 10 and the second inverter 20 by means of pulse width modulation.

[0054] For example, the controller 400 can determine, based on the desired output, a first drive mode that drives the first motor 100 using only the first inverter 10 without driving the second motor 200, a second drive mode that drives the first motor 100 using the first inverter 10 and the second inverter 20, and a third drive mode that drives both the first inverter 10 and the second inverter 20.

[0055] The controller 400 can determine the drive mode based on the comparison result between the input desired output and a predetermined first reference value and a second reference value greater than the first reference value, and execute motor drive according to the corresponding drive mode.

[0056] When the required output is less than or equal to a predetermined first reference value, the controller 400 can drive the motor in the first drive mode.

[0057] In the first drive mode, the controller 400 can adjust multiple third mode switching switches S31-S33 to a short-circuit state.

[0058] Under the control of the controller 400, the other ends of the windings L11-L13 of the first motor 100 are electrically connected to each other to form a Y-shaped connection structure that serves as the neutral point of the motor. The controller 400 can drive the first motor 100 by switching the switching elements S11-S16 in the first inverter 10 via pulse width modulation control, which is conventional for driving motors including those with a general Y-shaped connection structure.

[0059] The first drive mode is a drive mode that drives only the first motor 100 when the input is at the minimum required output. Therefore, the second inverter 20 and the second motor 200 are not driven in the first drive mode. Thus, the controller 400 suppresses unnecessary leakage current by controlling the plurality of first mode switching switches S41-S43 used to form an electrical connection between the first motor 100 and the second inverter 20, and the plurality of second mode switching switches S51-S53 used to form an electrical connection between the second inverter 20 and the second motor 200, to an open circuit state.

[0060] In addition, in the first drive mode, the controller 400 can also suppress leakage current by disconnecting all the switching elements S21-S26 in the second inverter 20.

[0061] When the required output is greater than a predetermined first reference value and less than or equal to a second reference value, the controller 400 can drive the motor in the second drive mode.

[0062] In the second drive mode, the controller 400 can adjust all the multiple second mode changeover switches S51-S53 and multiple third mode changeover switches S31-S33 to the open circuit state, and adjust multiple first mode changeover switches S41-S43 to the short circuit state.

[0063] Under the control of the controller 400, the other ends of the multiple windings L11-L13 in the first motor 100 can be electrically connected to each of the branches 21-23 of the second inverter 20 to form an open winding (OEW) connection structure, in which the two ends of the multiple windings L11-L13 of the first motor 100 are respectively connected to the inverter.

[0064] The controller 400 can drive the first motor 100 by switching the switching elements S11-S16 in the first inverter 10 and the switching elements S21-S26 in the second inverter 20 via pulse width modulation control, which is conventional for driving motors in the OEW mode.

[0065] Generally, it is well known that driving an OEW (Out-of-Wave) motor uses a larger voltage than driving a motor with a typical Y-connection structure, thus allowing for a larger output. Therefore, when an output greater than a first reference value and less than or equal to a second reference value is required while driving the first motor 100 in the first drive mode, the desired output can be achieved by adjusting the Y-connection structure of the first motor 100 to an open winding structure via mode switching switches S31-S33, S41-S43, and S51-S53.

[0066] When the required output is greater than the predetermined second reference value, the controller 400 can drive the motor in the third drive mode.

[0067] In the third drive mode, the controller 400 can adjust all the multiple second mode changeover switches S51-S53 and multiple third mode changeover switches S31-S33 to the short-circuit state, and adjust the multiple first mode changeover switches S41-S43 to the open-circuit state.

[0068] Under the control of the controller 400, the other ends of the multiple windings L11-L13 in the first motor 100 can be electrically connected to each other, and the branches 21-23 of the second inverter 20 can be electrically connected to the windings L21-L23 of the second motor 200 respectively. Therefore, a Y-shaped connection structure is formed by electrically connecting the other ends of the windings L11-L13 of the first motor 100 to each other to form the neutral point of the motor, and the second motor 200 is also connected to the second inverter 20 to allow driving the Y-shaped connection structure.

[0069] The controller 400 can drive the first motor 100 and the second motor 200 respectively by switching the switching elements S11-S16 in the first inverter 10 and the switching elements S21-S26 in the second inverter 20 respectively via conventional pulse width modulation control for driving motors including windings with a general Y-connection structure.

[0070] In this scenario, the first motor 100 can be a motor used for urban driving (e.g., driving on paved roads), while the second motor 200 can be a motor that requires additional driving force for harsh driving conditions (e.g., uneven roads, icy roads, etc.). For example, the first motor 100 can be a motor connected to the main drive wheel of a four-wheeled vehicle to be always driven while the vehicle is in motion, while the second motor 200 can be a motor connected to the auxiliary drive wheel of a four-wheeled vehicle to be selectively driven when greater driving force is required.

[0071] As described above, when the first motor 100 is driven in the first drive mode and an output greater than the second reference value is required, the controller 400 can immediately switch to a state where the second motor 200 can be driven by adjusting the mode switching switches S31-S33 and S41-S43, thereby quickly responding to the driving environment and ensuring the required output.

[0072] In the above description, the pulse width modulation control method for driving an inverter with a Y-shaped connection structure forming a neutral point and the pulse width modulation control method for driving an inverter with an open winding structure employ control methods known in the art, and therefore additional detailed descriptions will be omitted.

[0073] Figure 2 and Figure 3 This is a flowchart illustrating an operational example of a motor drive system according to an exemplary embodiment of the present disclosure.

[0074] Reference Figure 2 When the required output of the input is greater than the predetermined second reference value TH2 (Yes in P11), in order to drive the first motor 100 and the second motor 200 simultaneously with a Y-shaped connection structure, the controller 400 may first short-circuit multiple third mode switching switches S31-S33 to form a Y-shaped connection structure of the first motor 100 (P12).

[0075] In addition, the controller 400 can disconnect multiple first mode switching switches S41-S43 to adjust the first inverter 10 and the second inverter 20 respectively, and the controller 400 can short-circuit multiple second mode switching switches S51-S53 to electrically connect the second inverter 20 and the second motor 200 (P13).

[0076] Subsequently, the controller 400 can control the switching elements S11-S16 in the first inverter 10 and the switching elements S21-S26 in the second inverter 20 to switch in a pulse width modulation manner, thereby driving the first motor 100 and the second motor 200 respectively (P14).

[0077] When the required output of the input is less than the predetermined second reference value TH2 (No in P11) and therefore the second motor 200 does not need to be driven, the controller 400 can disconnect multiple second mode switching switches S51-S53 to make the second inverter 20 and the second motor 200 electrically isolated from each other (P15).

[0078] When the required output is determined to be greater than the first reference value TH1 (P16) based on the comparison between the predetermined first reference value TH1 and the required output, in order to control the first motor 100 in an open winding manner, the controller 400 can short-circuit a plurality of first mode switching switches S41-S43 to electrically connect the first motor 100 and the second inverter 20, and disconnect the third mode switching switches S51-S53 to insulate the other ends of the windings L11-L13 in the first motor 100 from each other.

[0079] After adjusting the mode switching switch as described above, the controller 400 can control the switching elements S11-S16 in the first inverter 10 and the switching elements S21-S26 in the second inverter 20 to switch in a pulse width modulation manner, thereby driving the first motor 100 (P17) in an open winding manner.

[0080] When it is determined in operation P16 that the desired output is less than or equal to the first reference value TH1 based on the comparison result between the predetermined first reference value TH1 and the desired output, in order to drive the first motor 100 in a Y-connection structure, the controller 400 can disconnect a plurality of first mode switching switches S41-S43 to electrically isolate the first motor 100 and the second inverter 20, and short-circuit the third mode switching switches S51-S53 to electrically connect the other ends of the windings L11-L13 in the first motor 100 to each other.

[0081] After adjusting the mode switching switch as described above, the controller 400 can control the switching elements S11-S16 in the first inverter 10 to switch in a pulse width modulation manner, thereby driving the first motor 100 (P18) in a Y-connection structure.

[0082] Reference Figure 3 The controller 400 can first determine whether to drive the first motor 100 with a Y-shaped connection structure (P21). That is, in operation P21, the controller 400 can determine whether to execute the first drive mode or the third drive mode by comparing the required output with the reference values ​​TH1 and TH2.

[0083] When the first motor 100 is not required to be driven by the Y-connection structure, the controller 400 can short-circuit multiple first mode switching switches S41-S43 to electrically connect the first motor 100 and the second inverter 20, disconnect multiple second mode switching switches to electrically isolate the second inverter 20 and the second motor 200, and disconnect multiple third mode switching switches S51-S53 to electrically isolate the other ends of the windings L11-L13 in the first motor 100 from each other (P22).

[0084] In operation P22, the controller 400 can control the switching elements S11-S16 in the first inverter 10 and the switching elements S21-S26 in the second inverter 20 to switch in a pulse width modulation manner, thereby driving the first motor 100 in an open winding manner.

[0085] In operation P21, when it is determined that the first motor 100 needs to be driven by a Y-connection, the controller 400 can then determine whether the second motor 200 needs to be driven (P23).

[0086] When the second motor 200 is not required to drive, the controller 400 can disconnect multiple first mode selector switches S41-S43 to electrically isolate the first motor 100 and the second inverter 20, and short-circuit multiple third mode selector switches S51-S53 to electrically connect the other ends of windings L11-L13 in the first motor 100 to each other (P24). In this case, the short-circuit / open-circuit state of the multiple second mode selector switches S51-S53 is irrelevant, but it is preferred to be open-circuited to suppress leakage current.

[0087] In operation P24, the controller 400 may not control the switching elements S21-S26 in the second inverter 20, but may control the switching elements S11-S16 in the first inverter 10 to switch in a pulse width modulation manner, so that only the first motor 100 can be driven in a Y-connection structure.

[0088] In operation P23, when it is determined that the second motor 200 needs to be driven, the controller 400 can disconnect multiple first mode switching switches S41-S43 to electrically isolate the first motor 100 and the second inverter 20, short-circuit multiple second mode switching switches S51-S53 to electrically connect the second inverter 20 and the second motor 200, and short-circuit multiple third mode switching switches S51-S53 to electrically connect the other ends of the windings L11-L13 in the first motor 100 to each other (P25).

[0089] In operation P25, after adjusting the mode switching switch, the controller 400 can control the switching elements S11-S16 in the first inverter 10 and the switching elements S21-S26 in the second inverter 20 to switch in pulse width modulation mode, thereby driving the first motor 100 and the second motor 200 respectively.

[0090] As described above, the motor drive systems according to various embodiments of this disclosure can utilize some inverters already applied to open-winding motor drive systems to drive additional motors when a large output is required, without the need to add a separate inverter. Therefore, the required output can be ensured simply by adding a motor, without adding an inverter. Consequently, the motor drive systems according to various embodiments of this disclosure can minimize the increase in manufacturing costs as output increases.

[0091] Furthermore, the motor drive system according to various embodiments of this disclosure can drive the motor in various ways that best meet the required output level, such as single-motor Y-connection drive, single-motor open winding (OEW) drive, and multi-motor drive, thereby improving the overall efficiency of the system.

[0092] Furthermore, terms related to control devices such as "controller," "control device," "control unit," "control apparatus," "control module," or "server" refer to hardware devices including a memory and a processor configured to execute one or more steps interpreted as an algorithmic structure. The memory stores algorithmic steps, and the processor executes the algorithmic steps to perform one or more processes of methods according to various exemplary embodiments of this disclosure. A control device according to exemplary embodiments of this disclosure can be implemented using a non-volatile memory configured to store algorithms for controlling the operation of various components of a vehicle or data regarding software commands for executing the algorithms, and a processor configured to perform the aforementioned operations using the data stored in the memory. The memory and processor can be separate chips. Alternatively, the memory and processor can be integrated into a single chip. The processor can be implemented as one or more processors. The processor can include various logic circuits and arithmetic circuits, can process data according to a program provided by the memory, and can generate control signals based on the processing results.

[0093] The control device may be at least one microprocessor operated by a predetermined program, which may include a series of commands for performing the methods included in the various exemplary embodiments described above in this disclosure.

[0094] The invention described above can also be embodied as computer-readable code on a computer-readable recording medium. A computer-readable recording medium is any data storage device capable of storing data that can be subsequently read by a computer system and storing and executing program instructions that can be subsequently read by a computer system. Examples of computer-readable recording media include hard disk drives (HDDs), solid-state drives (SSDs), silicon disk drives (SDDs), read-only memory (ROM), random access memory (RAM), CD-ROMs, magnetic tapes, floppy disks, optical data storage devices, and implementations as carrier waves (e.g., transmitted over the Internet). Examples of program instructions include machine language code generated by a compiler, and high-level language code that can be executed by a computer using an interpreter, etc.

[0095] In various exemplary embodiments of this disclosure, each of the above operations may be performed by a control device, and the control device may be configured by multiple control devices or a single integrated control device.

[0096] In various exemplary embodiments of this disclosure, the control device may be implemented in hardware or software, or in a combination of hardware and software.

[0097] In addition, the terms "unit" and "module" disclosed in the specification refer to a unit used to process at least one function or operation, which can be implemented by hardware, software or a combination thereof.

[0098] For ease of interpretation and precise definition of the appended claims, the features are described using the terms “upper,” “lower,” “inner,” “outer,” “up,” “lower,” “upward,” “downward,” “front,” “back,” “behind,” “inner,” “outer,” “inward,” “outer,” “within,” “outside,” “forward,” and “backward,” with reference to the location of the features in the exemplary embodiments shown in the figures. It will be further understood that the term “connection” or its derivatives refer to both direct and indirect connections.

[0099] For purposes of illustration and description, the foregoing description of specific exemplary embodiments of this disclosure has been provided. These descriptions are not intended to be exhaustive or to limit this disclosure to its precise forms, and it will be apparent that many modifications and variations are possible in accordance with the foregoing teachings. Exemplary embodiments were chosen and described to explain certain principles of this disclosure and its practical application, so that others skilled in the art can implement and utilize the various exemplary embodiments of this disclosure and their various alternatives and modifications. The scope of this disclosure is intended to be defined by the appended claims and their equivalents.

Claims

1. A motor drive system, comprising: The first motor includes a plurality of first windings corresponding to a plurality of phases; The second motor includes a plurality of second windings corresponding to a plurality of phases, the first ends of the plurality of second windings being connected to each other; The first inverter includes a DC terminal connected to a DC voltage source and an AC terminal connected to the respective first ends of the plurality of first windings; A first switching section includes a plurality of first mode switching switches, the first ends of which are respectively connected to the second ends of the plurality of first windings; The second inverter includes a DC terminal connected to the DC voltage source and an AC terminal connected to the respective second terminal of the plurality of first mode switching switches; The second switching section includes a plurality of second mode switching switches, the two ends of which are connected to the AC terminals of the second inverter and the respective second ends of the plurality of second windings; The third switching section includes a plurality of third mode switching switches, the first ends of the plurality of third mode switching switches are respectively connected to the second ends of the plurality of first windings, and the second ends of the plurality of third mode switching switches are connected to each other; as well as The controller is connected to the first inverter, the second inverter, the first switch section, the second switch section, and the third switch section, and is configured to control the short-circuit / open-circuit states of the plurality of first mode switching switches, the plurality of second mode switching switches, and the plurality of third mode switching switches according to the drive requests of the first motor and the second motor.

2. The motor drive system according to claim 1, wherein, The controller is configured to: In the mode of driving the first motor without driving the second motor, the plurality of first mode switching switches are adjusted to the short-circuit state, the plurality of second mode switching switches and the plurality of third mode switching switches are adjusted to the open-circuit state, and the first inverter and the second inverter connected to the two ends of the first winding are adjusted to drive the first motor in an open winding manner.

3. The motor drive system according to claim 1, wherein, The controller is configured to: In the mode of driving the first motor without driving the second motor, the plurality of third mode switching switches are adjusted to the short-circuit state to form a Y-shaped connection at the second end of the plurality of first windings, and the first inverter is adjusted to drive the first motor.

4. The motor drive system according to claim 3, wherein, The controller is configured to: Adjust the plurality of first mode switching switches to the open circuit state, adjust the plurality of second mode switching switches to the open circuit state, or adjust the switching elements in the second inverter to the open circuit state.

5. The motor drive system according to claim 1, wherein, The controller is configured to: In the mode of simultaneously driving the first motor and the second motor, the plurality of third mode switching switches are adjusted to the short-circuit state to form a Y-shaped connection at the second end of the plurality of first windings, and the first inverter is adjusted to drive the first motor. In addition, the plurality of first mode switching switches are adjusted to the open-circuit state, the plurality of second mode switching switches are adjusted to the short-circuit state, and the second inverter is adjusted to drive the second motor.

6. The motor drive system according to claim 1, wherein, The controller is configured to: The system receives the input of the desired output and determines the mode for driving the first motor and the second motor based on the comparison between the input of the desired output and a predetermined first reference value and a second reference value greater than the first reference value.

7. The motor drive system according to claim 6, wherein, The controller is configured to: When the desired output is less than or equal to the predetermined first reference value, the plurality of third mode switching switches are adjusted to the short-circuit state to form a Y-connection at the second end of the plurality of first windings, and the first inverter is adjusted to drive the first motor.

8. The motor drive system according to claim 7, wherein, The controller is configured to: Adjust the plurality of first mode switching switches to the open circuit state, adjust the plurality of second mode switching switches to the open circuit state, or adjust the switching elements in the second inverter to the open circuit state.

9. The motor drive system according to claim 6, wherein, The controller is configured to: When the required output is greater than the first reference value and less than or equal to the second reference value, the plurality of first mode switching switches are adjusted to the short-circuit state, the plurality of second mode switching switches and the plurality of third mode switching switches are adjusted to the open-circuit state, and the first inverter and the second inverter connected to the two ends of the first winding are adjusted to drive the first motor in an open winding manner.

10. The motor drive system according to claim 6, wherein, The controller is configured to: When the required output is greater than the second reference value, the plurality of third mode switching switches are adjusted to the short-circuit state to form a Y-shaped connection at the second end of the plurality of first windings, and the first inverter is adjusted to drive the first motor. The plurality of first mode switching switches are adjusted to the open-circuit state, the plurality of second mode switching switches are adjusted to the short-circuit state, and the second inverter is adjusted to drive the second motor.

11. A control method for a motor drive system, the motor drive system comprising: The first motor includes a plurality of first windings corresponding to a plurality of phases; The second motor includes a plurality of second windings corresponding to a plurality of phases, the first ends of the plurality of second windings being connected to each other; the first inverter includes a DC terminal connected to a DC voltage source and an AC terminal connected to the respective first ends of the plurality of first windings; the first switching section includes a plurality of first mode switching switches, the first ends of the plurality of first mode switching switches being respectively connected to the second ends of the plurality of first windings. A second inverter includes a DC terminal connected to the DC voltage source and an AC terminal connected to the respective second terminals of the plurality of first mode switching switches; a second switching section includes a plurality of second mode switching switches, the two ends of which are connected to the AC terminal of the second inverter and the respective second terminals of the plurality of second windings; a third switching section includes a plurality of third mode switching switches, the first terminals of which are respectively connected to the second terminals of the plurality of first windings, and the second terminals of the plurality of third mode switching switches are connected to each other. The method includes: The controller connected to the first inverter, the second inverter, the first switch section, the second switch section, and the third switch section controls the short-circuit / open-circuit states of the plurality of first mode switching switches, the plurality of second mode switching switches, and the plurality of third mode switching switches according to the drive requests of the first motor and the second motor.

12. The method according to claim 11, wherein, The controller is configured to: In the mode of driving the first motor without driving the second motor, the plurality of first mode switching switches are adjusted to the short-circuit state, the plurality of second mode switching switches and the plurality of third mode switching switches are adjusted to the open-circuit state, and the first inverter and the second inverter connected to the two ends of the first winding are adjusted to drive the first motor in an open winding manner.

13. The method according to claim 11, wherein, The controller is configured to: In the mode of driving the first motor without driving the second motor, the plurality of third mode switching switches are adjusted to the short-circuit state to form a Y-shaped connection at the second end of the plurality of first windings, and the first inverter is adjusted to drive the first motor.

14. The method according to claim 13, wherein, The controller is configured to adjust the plurality of first mode switching switches to the open circuit state, adjust the plurality of second mode switching switches to the open circuit state, or adjust the switching elements in the second inverter to the open circuit state.

15. The method according to claim 11, wherein, The controller is configured to: In the mode of simultaneously driving the first motor and the second motor, the plurality of third mode switching switches are adjusted to the short-circuit state to form a Y-shaped connection at the second end of the plurality of first windings, and the first inverter is adjusted to drive the first motor. In the other mode, the plurality of first mode switching switches are adjusted to the open-circuit state, the second mode switching switches are adjusted to the short-circuit state, and the second inverter is adjusted to drive the second motor.

16. The method according to claim 11, wherein, The controller is configured to: The system receives the input of the desired output and determines the mode for driving the first motor and the second motor based on the comparison between the input of the desired output and a predetermined first reference value and a second reference value greater than the first reference value.

17. The method according to claim 16, wherein, The controller is configured to: When the desired output is less than or equal to the predetermined first reference value, the plurality of third mode switching switches are adjusted to the short-circuit state to form a Y-connection at the second end of the plurality of first windings, and the first inverter is adjusted to drive the first motor.

18. The method according to claim 17, wherein, The controller is configured to: Adjust the plurality of first mode switching switches to the open circuit state, adjust the plurality of second mode switching switches to the open circuit state, or adjust the switching elements in the second inverter to the open circuit state.

19. The method of claim 16, wherein, The controller is configured to: When the required output is greater than the first reference value and less than or equal to the second reference value, the plurality of first mode switching switches are adjusted to the short-circuit state, the plurality of second mode switching switches and the plurality of third mode switching switches are adjusted to the open-circuit state, and the first inverter and the second inverter connected to the two ends of the first winding are adjusted to drive the first motor in an open winding manner.

20. The method of claim 16, wherein, The controller is configured to: When the required output is greater than the second reference value, the plurality of third mode switching switches are adjusted to the short-circuit state to form a Y-shaped connection at the second end of the plurality of first windings, and the first inverter is adjusted to drive the first motor. The plurality of first mode switching switches are adjusted to the open-circuit state, the plurality of second mode switching switches are adjusted to the short-circuit state, and the second inverter is adjusted to drive the second motor.

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