MOTOR DRIVE DEVICE AND METHOD FOR CONTROLLING THE SAME

Abstract

A motor drive device includes a motor having a plurality of windings, a dual inverter including a first inverter connected to first ends of the plurality of windings and a second inverter connected to second ends of the plurality of windings, and configured to drive the motor through at least one of the first inverter and the second inverter according to a motor drive mode, and a controller configured to determine whether flux weakening control is performed according to an available voltage level of the dual inverter when a switching condition of the motor drive mode is satisfied, and to perform the flux weakening control by linearly adjusting an output voltage level of the dual inverter for a preset time interval for which the flux weakening control is performed.

Description

Technical area

[0001] The present disclosure relates to a motor driving device and a method for controlling the same, and more particularly to a motor driving device for stabilizing a torque output from a motor when switching a motor driving mode and a method for controlling the same. background

[0002] Recently, there has been a need for a motor drive technology that improves system efficiency while simultaneously covering both low and high power ranges with one motor. Therefore, a technology is introduced that allows one motor to be operated in two different modes using two inverters and a mode switch. These are closed-end wiring (CEW), where one motor is driven by one inverter via Y-wiring, and open-end wiring (OEW), where one motor is driven by two inverters.

[0003] Generally, switching between CEW mode and OEW mode can be determined by the reverse magnetic flux of the motor and the motor torque. However, if the motor drive mode is switched at the time when a switching condition is met, the motor output torque may become unstable due to the rapid decrease in the available voltage of the inverter. To solve this problem, there is a method for setting a switching reference line with maximum efficiency, but this method may cause a decrease in the efficiency of a motor drive device.

[0004] The information disclosed in the Background section above is intended to facilitate understanding of the background of the present disclosure and is not to be construed as an acknowledgment that this information is part of the prior art. SUMMARY

[0005] The present disclosure relates to stabilizing the torque output from a motor when switching a motor drive mode by linearly adjusting an output voltage level of an inverter for a predetermined time interval when switching a motor drive mode.

[0006] The technical problems to be solved in the present disclosure are not limited to the technical problems described above, and other technical problems not mentioned can be clearly understood by those skilled in the art to which the present disclosure relates from the following description.

[0007] To solve the above-mentioned technical problems, a motor drive device may include a motor having a plurality of windings, a dual inverter including a first inverter connected to first ends of the plurality of windings and a second inverter connected to second ends of the plurality of windings, and configured to drive the motor by at least one of the first inverter or the second inverter according to a motor drive mode, and a controller configured to determine whether flux weakening control is performed according to an available voltage level of the dual inverter when a switching condition of the motor drive mode is met, and to perform the flux weakening control by linearly adjusting an output voltage level of the dual inverter for a preset time interval,for which the flux weakening control is carried out.,

[0008] In one embodiment, the preset time interval may correspond to a time interval between a time at which the switching condition of the motor drive mode is satisfied and a time at which the motor drive mode is switched.

[0009] In one embodiment, the motor drive device may further comprise a plurality of mode switches, the first ends of which are connected to the second ends of the plurality of windings and the second ends of which are connected to each other. The motor drive mode may include a first drive mode in which the plurality of mode switches are turned on and the motor is driven by the first inverter among the first and second inverters, and a second drive mode in which the plurality of mode switches are turned off and the motor is driven by the first and second inverters.

[0010] In one embodiment, the switching condition of the motor operating mode may correspond to a switching condition for changing from the second drive mode to the first drive mode.

[0011] In one embodiment, the controller may set the output voltage level to a voltage limit level of the first drive mode for the preset time interval when the available voltage level exceeds the voltage limit level of the first drive mode, and then switch from the second drive mode to the first drive mode.

[0012] In one embodiment, the controller may switch from the second drive mode to the first drive mode without performing the flux weakening control when the available voltage level is less than or equal to the voltage limit level of the first drive mode.

[0013] In one embodiment, the available voltage level may vary depending on the DC terminal voltage of the dual inverter and may be set higher in the second drive mode than in the first drive mode.

[0014] In one embodiment, the controller may adjust the output voltage level by changing an adjustment factor of the available voltage level for the preset time interval when the flux weakening control is performed.

[0015] In one embodiment, the controller may stop an operation of changing the adjustment factor of the available voltage level if the switching condition is not met for the preset time interval.

[0016] In order to solve the aforementioned technical problems, a method for controlling a motor drive device having a dual inverter configured to drive a motor according to a motor drive mode may further include determining whether to perform flux weakening control according to an available voltage level of the dual inverter when a switching condition of the motor drive mode is satisfied, and performing the flux weakening control by linearly adjusting an output voltage level of the dual inverter for a preset time interval for which the flux weakening control is performed.

[0017] In one embodiment, the preset time interval may correspond to a time interval between a time at which the switching condition of the motor drive mode is satisfied and a time at which the motor drive mode is switched.

[0018] In one embodiment, the motor drive mode may include a first drive mode in which a neutral point of the motor is formed and the motor is driven by a first inverter of first and second inverters included in the dual inverter, and a second drive mode in which the neutral point of the motor is not formed and the motor is driven by the first and second inverters.

[0019] In one embodiment, the switching condition of the motor drive mode may correspond to a switching condition from the second drive mode to the first drive mode.

[0020] In one embodiment, the determination may include determining execution of the flux weakening control when the available voltage level exceeds a voltage limit level of the first drive mode.

[0021] In one embodiment, the determination may include determining switching from the second mode to the first mode without performing the flux weakening control when the available voltage level is less than or equal to the voltage limit level of the first drive mode.

[0022] In one embodiment, the available voltage level may vary depending on the DC terminal voltage of the dual inverter, and may be set higher in the second drive mode than in the first drive mode.

[0023] In one embodiment, the adjustment may include adjusting the output voltage level by changing an adjustment factor of the available voltage level for the preset time interval when the flux weakening control is performed.

[0024] In one embodiment, the motor drive device may further include stopping an operation for changing the adjustment factor of the available voltage level if the switching condition is not met for the preset time interval.

[0025] According to the present disclosure, it is possible to stabilize the torque output from the motor when switching the motor drive mode by linearly adjusting the output voltage level of the inverter for the preset time interval when switching the motor drive mode.

[0026] The effects achievable by the present disclosure are not limited to the effects described above, and other effects not mentioned can be clearly understood by those skilled in the art to which the disclosure refers from the following description.

[0027] The methods and apparatus of the present disclosure have additional features and advantages that will be apparent or more fully set forth in the accompanying drawings included herein and the following detailed description, which together serve to explain certain principles of the present disclosure. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a circuit diagram of a motor drive device according to an embodiment of the present disclosure; Fig. 2 is a view for describing switching of the motor drive mode according to an embodiment of the present disclosure; Fig. 3 is a flowchart for describing a method for controlling the motor drive device according to an embodiment of the present disclosure; and Fig. 4 and Fig. 5 are views for describing a process of switching the motor drive mode according to an embodiment of the present disclosure.

[0028] It should be understood that the accompanying drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the present disclosure. The specific constructional features of the present disclosure as contained herein, including, for example, specific dimensions, orientations, positions, and shapes, will be determined in part by the particular intended application and environment of use.

[0029] In the figures, reference numbers refer to the same or equivalent parts of the present disclosure in the several figures of the drawing. DETAILED DESCRIPTION

[0030] Hereinafter, the embodiments disclosed in this specification will be described in detail with reference to the accompanying drawings, and the same or similar components will be denoted by the same reference numerals regardless of the drawing symbols, and overlapping descriptions will be omitted. The suffixes "module" and "unit" for components used in the following description are indicated or used interchangeably in consideration of the convenience of writing the specification and do not have inherent meanings or roles separate from each other. Furthermore, in describing the embodiments disclosed in this specification, when it is determined that a detailed description of a related known technology might obscure the gist of the embodiments disclosed in this specification, a detailed description thereof will be omitted.Furthermore, the accompanying drawings are only for facilitating the understanding of the embodiments disclosed in this specification, and it should be understood that the technical spirit disclosed in this specification is not limited by the accompanying drawings, and all changes, equivalents, or substitutes included within the spirit and technical scope of the present disclosure are included in the accompanying drawings.

[0031] Terms containing ordinal numbers such as "second" or "first" can be used to describe different components, but the components are not restricted by the terms. The terms are used only to distinguish the individual components.

[0032] When a particular component is described as "connected" or "coupled" to another component, it is understood that it may be directly connected or coupled to another component, or other components may be interposed. Conversely, when a particular component is described as "directly connected" or "directly coupled" to another component, it is understood that no other components are interposed.

[0033] The singular expression includes the plural unless the context clearly indicates otherwise.

[0034] In the Specification, terms such as "comprise" or "have" are to be understood as indicating the presence of a feature, number, step, operation, component, part, or combination thereof described in the Specification, but do not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0035] Additionally, a unit or control unit, included in the name of an engine control unit (MCU), hybrid control unit (HCU), or the like, is the generally used term to refer to a controller for controlling a specific function of a vehicle and does not imply a generic functional unit. For example, each controller may include a communication device for communicating with another controller to control the relevant functions, a memory for storing an operating system, logical instructions, input / output information, and the like, and one or more processors for performing determinations, calculations, decisions, and the like necessary to control the relevant functions.

[0036] Fig. 1 is a circuit diagram of a motor drive device according to an embodiment of the present disclosure.

[0037] Referring to Fig. 1, a motor drive device according to an embodiment of the present disclosure may include a dual inverter 10 and 20, a motor 30 having a plurality of windings C1, C2, and C3 each corresponding to one of a plurality of phases, a mode switching unit 40, a battery 50, and a controller 100.

[0038] The first inverter 10 may include a plurality of first switching elements S11 to S16 connected to one end of the plurality of windings C1, C2, and C3, and the second inverter 20 may include a plurality of second switching elements S21 to S26 connected to the other ends of the plurality of windings C1, C2, and C3. The mode switching unit 40 may include a plurality of mode switching switches S31, S32, and S33. The controller 100 can control the ON / OFF states of the first switching elements S11, S12, S13, S14, S15 and S16, the second switching elements S21, S22, S23, S24, S25 and S26 and the mode switching switches S31, S32 and S33 based on a motor request output (ie, a torque command for the motor), a direct current (DC) terminal voltage (ie, a voltage of the battery) of the inverters 10 and 20, a phase current of the motor and a motor angle.

[0039] The first inverter 10 may include a plurality of branches 11, 12, and 13 to which the DC voltage of the battery 50 is applied. Each of the branches 11, 12, and 13 may correspond to one of a plurality of phases of the motor 30 so that electrical connections can be made. More specifically, the first branch 11 may include two switching elements S11 and S12 connected in series between the two ends of the battery 50, and a connection node of the two switching elements S11 and S12 may be connected to one end of the winding C1 of a phase in the motor 30 so that alternating current (AC) corresponding to one of the plurality of phases is input or output.Likewise, the second branch 12 may include two switching elements S13 and S14 connected in series between both ends of the battery 50, and a connection node of the two switching elements S13 and S14 may be connected to one end of the winding C2 of a phase in the motor 30, so that alternating current corresponding to one of the multiple phases is input or output. Furthermore, the third branch 13 may include two switching elements S15 and S16 connected in series between both ends of the battery 50, and a connection node of the two switching elements S15 and S16 may be connected to one end of the winding C3 of a phase in the motor 30, so that alternating current corresponding to one of the multiple phases is input or output.

[0040] The second inverter 20 may include a plurality of branches 21, 22, and 23 to which the DC voltage of the battery 50 is applied. Each of the branches 21, 22, and 23 may correspond to one of the multiple phases of the motor 30 so that electrical connections can be made. More specifically, the first branch 21 may include the two switching elements S21 and S22 connected in series between the two ends of the battery 50, and the connection node of the two switching elements S21 and S22 may be connected to the other end of the winding C1 of one phase in the motor 30 so that the AC current corresponding to one of the plurality of phases is input or output.Likewise, the second branch 22 may include two switching elements S23 and S24 connected in series between both ends of the battery 50, and the connection node of the two switching elements S23 and S24 may be connected to the other end of the winding C2 of one phase in the motor 30, so that the alternating current corresponding to one of the plurality of phases is input or output. Furthermore, the third branch 23 may include two switching elements S25 and S26 connected in series between both ends of the battery 50, and the connection node of the two switching elements S25 and S26 may be connected to the other end of the winding C3 of one phase in the motor 30, so that the alternating current corresponding to one of the plurality of phases is input or output.

[0041] The plurality of mode switching switches S31, S32, and S33 may each have one end connected to the plurality of windings C1, C2, and C3, and the other end connected to each other. The plurality of mode switching switches S31, S32, and S33 may use various switching devices known in the art, such as a metal-oxide-semiconductor field-effect transistor (MOSFET), an insulated-gate bipolar transistor (IGBT), a thyristor, and a relay.

[0042] Although in Fig. 1, the motor drive device may further include a so-called Y-capacitor connecting two capacitors in series between a positive (+) DC terminal and a negative (-) DC terminal and grounding a connection node between the capacitors.

[0043] The controller 100 can control the drive of the motor 30 by switching the switching elements S11, S12, S13, S14, S15, S16, S21, S22, S23, S24, S25, and S26 included in the first inverter 10 and the second inverter 20 through pulse width modulation control based on a demand power required for the motor 30.

[0044] Furthermore, the controller 100 may control the ON / OFF state of the mode switching switches S31, S32, and S33 included in the mode switching unit 40 according to the motor drive mode. The motor drive mode may include a first drive mode and a second drive mode. In this case, the first drive mode may be referred to as "CEW mode," and the second drive mode may be referred to as "OEW mode."

[0045] The dual inverters 10 and 20 can drive the motor 30 through the first inverter 10 or the second inverter 20 depending on the motor drive mode. More specifically, the controller 100 can control the mode switching switches S31, S32, and S33 to turn on so that the other ends of the multiple windings C1 to C3 form a neutral point when the CEW mode is executed, and drive the motor 30 through the first inverter 10 of the two inverters 10 and 20. In contrast, the controller 100 can control the mode switching switches S31, S32, and S33 to turn off so that the other ends of the multiple windings C1 to C3 do not form a neutral point when the OEW mode is executed, and drive the motor 30 through the first inverter 10 of the two inverters 10 and 20.

[0046] Fig. 2 is a view for describing switching of the motor drive mode according to an embodiment of the present disclosure.

[0047] In Fig. 2 shows an operating point diagram of the engine, which indicates an output limit curve L1 of the CEW mode, an output limit curve L2 of the OEW mode, and a mode change reference line L3 based on an efficiency diagram.

[0048] Output limit curves L1 and L2 may specify a limit value for the motor's output torque for each motor speed (e.g., RPM) in each motor drive mode. Output limit curve L2 may have an output limit value greater than or equal to output limit curve L1 in at least part of a speed range. Output limit curves L1 and L2 may be set taking into account the durability, heat generation, current controllability, or the like of the motor and the inverter.

[0049] The mode switching reference line L3 based on the efficiency map (not shown) may correspond to a boundary line between a high-efficiency region of the CEW mode and a high-efficiency region of the OEW mode. The efficiency map may contain information about a higher-efficiency mode between the CEW mode and the OEW mode in each combination of the motor torque and counter magnetic flux and, depending on the implementation, may be in the form of a table. For example, the efficiency map may be derived based on a result of measuring the motor losses as a function of the motor speed and torque in each motor drive mode for each DC terminal voltage of the inverter through a test. In this case, the motor counter magnetic flux may be inversely proportional to the DC terminal voltage (i.e.to the battery voltage) of the inverter and proportional to the speed of the motor.

[0050] According to the embodiment, the mode change reference line L3 may have a shape such as L3' according to the specifications of the motor drive device. Fig. However, the mode switching reference lines L3 and L3' shown in Figure 2 are exemplary, and the present disclosure is not necessarily limited thereto.

[0051] To switch the motor drive mode according to the mode switching reference line L3, the controller 100 may switch the CEW mode and the OEW mode in both directions according to a torque command value and a motor return magnetic flux value with reference to the efficiency map. In this case, the reverse magnetic flux value may be calculated based on the motor torque command, the inverter DC terminal voltage, and the motor target speed. According to the embodiment, the controller 100 may correct the mode switching reference line by considering the output limit, hysteresis, or the like for the motor drive mode, and in this case, switch the motor drive mode according to the torque command value and the motor return magnetic flux value based on the corrected mode switching reference line.

[0052] The following describes a method for controlling the motor drive device to stabilize the torque output from the motor when switching the motor drive mode by linearly adjusting the output voltage level of the inverter for a predetermined time interval when switching the motor drive mode.

[0053] Fig. 3 is a flowchart for describing a method of controlling the motor drive device according to an embodiment of the present disclosure.

[0054] Referring to Fig. 3, the controller 100 may control the drive of the motor 30 by the first inverter 10 or the second inverter 20 according to the motor drive mode (S101). As described above, the motor drive mode may include the CEW mode and the OEW mode. The CEW mode may correspond to a mode in which the plurality of mode switching switches S31, S32, and S33 are turned on, and the motor 30 is driven by the first inverter 10 of the first and second inverters 10 and 20. In contrast, the OEW mode may correspond to a mode in which the plurality of mode switching switches S31, S32, and S33 are turned off, and the motor 30 is driven by the first and second inverters 10 and 20.

[0055] Thereafter, the controller 100 may determine whether the motor drive mode switching condition is satisfied based on the reverse magnetic flux of the motor 30 and the torque of the motor 30 (S102). In this embodiment, the motor drive mode switching condition may correspond to the switching condition from the OEW mode to the CEW mode. If the switching condition from the OEW mode to the CEW mode is not satisfied (NO in S102), the controller 100 may continue to execute the OEW mode in S101.

[0056] When the motor drive mode switching condition is met (i.e., when the switching condition from OEW mode to CEW mode is met) (YES in S102), the controller 100 may determine whether to perform flux weakening control depending on the available voltage levels of the dual inverters 10 and 20 (S103). More specifically, the controller 100 may determine whether to perform flux weakening control depending on whether the available voltage levels of the dual inverters 10 and 20 exceed the CEW mode voltage limit level.

[0057] Here, flux-weakening control refers to a control scheme that increases the speed range of a motor under given current and voltage limits in the motor drive device. Specifically, when the motor drive conditions exceed a certain torque or speed, the output voltage of the inverters (10, 20) exceeds the available voltage. By appropriately adjusting the output voltage within the available voltage through flux-weakening control, the motor speed range can be expanded. Such control is based on the property that the magnetic flux is proportional to the output voltage and inversely proportional to the torque.

[0058] Flux weakening control is performed when the output voltage level is higher than the available voltage level. The region around the operating point where switching occurs between CEW and OEW modes corresponds to the flux weakening control region for CEW mode and the non-flux weakening control region for OEW mode.

[0059] Therefore, in the present embodiment, flux weakening control is performed to prevent torque shock during the mode switching interval from the OEW mode to the CEW mode due to a rapid drop in the available voltage level. In other words, when a mode switching to the OEW mode is to occur, the available voltage in the OEW mode is forcibly reduced to the available voltage in the CEW mode for a predetermined time interval, while flux weakening control is not necessarily performed. By reducing the available voltage level, the output voltage level can be lowered to a level suitable for the CEW mode before the CEW mode is activated.

[0060] In this case, the available voltage levels of dual inverters 10 and 20 can vary depending on the DC terminal voltage (i.e., the battery voltage) of dual inverters 10 and 20, and can be set higher in OEW mode than in CEW mode. For example, the available voltage level in CEW mode can be equal to Vdc (battery voltage), and the available voltage level in OEW mode can be equal to Vdc *√3.

[0061] When the available voltage levels of the dual inverters 10 and 20 are less than or equal to the voltage limit level of the CEW mode (NO in S103), the controller 100 can switch the OEW mode to the CEW mode without performing the flux weakening control (S106).

[0062] On the other hand, if the available voltage levels of the dual inverters 10 and 20 exceed the voltage limit level of the CEW mode (YES in S103), the controller 100 may linearly adjust the output voltage levels of the dual inverters 10 and 20 to the voltage limit level of the CEW mode for the preset time interval for which the weak magnetic flux is performed (S104 and S105), and then switch the OEW mode to the CEW mode (S106). In this case, the preset time interval may correspond to a time interval between the time when the switching condition of the motor drive mode is satisfied and the time when the motor drive mode is switched. In the embodiment, the preset time interval may correspond to the time interval between the time when the switching condition from the OEW mode to the CEW mode is satisfied and the time when the CEW mode is executed.

[0063] Specifically, when the available voltage levels of dual inverters 10 and 20 exceed the voltage limit of the CEW mode (YES in S103), the controller 100 can adjust the output voltage levels of dual inverters 10 and 20 by changing an adjustment factor of the available voltage levels of dual inverters 10 and 20 (S104). When the OEW mode is implemented, the available voltage levels of both inverters 10 and 20 can be equal to Vdc *√3 * "adjustment factor of the available voltage levels".

[0064] Thereafter, the controller 100 can determine whether the preset time interval has elapsed (S105).

[0065] When the preset time interval has elapsed (YES in S105), the controller 100 can switch from the OEW mode to the CEW mode (S106).

[0066] Before the preset time interval elapses (NO in S105), the controller 100 may determine whether the switching condition (ie, the switching condition from the OEW mode to the CEW mode) of the motor drive mode is not satisfied (S107).

[0067] When the motor drive mode switching condition is satisfied (NO in S107), the controller 100 may maintain the execution of the flux weakening control (S104).

[0068] If the motor drive mode switching condition is not met for the preset time interval (YES in S107), the controller 100 may terminate the process of changing the available voltage level adjustment factor (S108). For example, the controller 100 may change the available voltage level adjustment factor to "1" at the time when the motor drive mode switching condition is not met. Therefore, the controller 100 may prevent flux weakening control from being performed in a region where the motor drive mode switching condition is not met.

[0069] Meanwhile, unlike the embodiment in which the flux weakening control is performed for the preset time interval, a method of performing the flux weakening control while the actual back magnetic flux of the motor is in a range near the mode switching reference line may be considered, but since the actual back magnetic flux of the motor may continuously be in the range near the mode switching reference line, the efficiency of the motor driving device may be reduced.

[0070] Fig. 4 and Fig. 5 are views for describing a method of switching the motor drive mode according to an embodiment of the present disclosure.

[0071] With reference to Fig. 4, at a time ta, the controller 100 may determine that the switching condition from the OEW mode to the CEW mode is met. The controller 100 may linearly decrease the adjustment factor of the available voltage level from "1.0" to "x" for an interval from time ta to a time tb (i.e., the preset time interval). Thereafter, at time tb, the controller 100 may nonlinearly increase the adjustment factor of the available voltage level from "x" to "1.0" and switch the motor drive mode from the OEW mode to the CEW mode.

[0072] In this case, the adjustment factor of the available voltage level can be adjusted in a direction that lowers the available voltage level to the voltage limit level of the CEW mode for the preset time interval. "x" and the preset time interval can be set differently depending on the design. As the preset time interval for which flux weakening control is performed increases, the change in motor torque decreases, but the efficiency of the motor drive device may be reduced.

[0073] In Fig.Figure 5 illustrates a view in which the operating points of the dual inverters 10 and 20 are moved along a constant torque curve Te for the current time interval (time interval from time ta to time tb). At time ta, the operating points of the dual inverters 10 and 20 are located on the constant torque curve Te, and for the specified time interval (time interval from time ta to time tb), the operating points of the dual inverters 10 and 20 can be shifted linearly up to the voltage limit of the CEW mode.

[0074] Meanwhile, the present disclosure described above can be implemented as computer-readable code on a medium on which a program is recorded. The computer-readable recording medium includes all types of recording media on which data readable by a computer system is stored. Examples of computer-readable media include a hard disk drive (HDD), a solid state disk (SSD), a silicon disk drive (SDD), a read-only memory (ROM), a random access memory (RAM), a CD-ROM, a magnetic tape, a floppy disk, an optical data storage device, etc. Therefore, the above detailed description should not be construed as limiting in all respects and should be considered as illustrative.The scope of the present disclosure should be determined by reasonable interpretation of the appended claims, and all changes within the equivalent scope of the present disclosure are included within the scope of the present disclosure.

Claims

[1] Motor drive device, comprising: a motor with a plurality of windings; a dual inverter having a first inverter connected to the first ends of the plurality of windings and a second inverter connected to the second ends of the plurality of windings, and configured to drive the motor through the first inverter and / or the second inverter according to a motor drive mode; and a controller configured to determine whether to perform flux weakening control for adjusting an output voltage level of the dual inverter based on an available voltage level of the dual inverter when a switching condition of the motor drive mode is met, and to perform the flux weakening control by adjusting the available voltage level of the dual inverter for a preset time interval. [2] The motor driving device according to claim 1, wherein the preset time interval corresponds to a time interval from a time point at which the switching condition of the motor driving mode is satisfied to a time point at which the motor driving mode is switched. [3] The motor driving device according to claim 1, further comprising a plurality of mode switching switches, the first ends of which are respectively connected to the second ends of the plurality of windings and the second ends of which are connected to each other, wherein the motor driving mode includes: a first drive mode in which the plurality of mode switching switches are turned on and the motor is driven by the first and second inverters via the first inverter; and a second operating mode in which the plurality of mode switching switches are turned off and the motor is driven via the first and second inverters. [4] The motor drive device according to claim 3, wherein the switching condition of the motor drive mode corresponds to a switching condition for switching from the second drive mode to the first drive mode. [5] The motor drive device according to claim 4, wherein the controller is further configured: adjust the output voltage level to a voltage limit level of the first drive mode for the preset time interval when the available voltage level exceeds the voltage limit level of the first drive mode; and to switch from the second drive mode to the first drive mode. [6] The motor driving device according to claim 4, wherein the controller is further configured to switch from the second drive mode to the first drive mode without performing the flux weakening control when the available voltage level is less than or equal to a voltage limit level of the first drive mode. [7] The motor drive device according to claim 3, wherein the available voltage level varies depending on a DC terminal voltage of the dual inverter and is set higher in the second drive mode than in the first drive mode. [8] The motor driving device according to claim 1, wherein the controller is further configured to adjust the output voltage level by changing an adjustment factor of the available voltage level for the preset time interval when the flux weakening control is performed. [9] The motor driving device according to claim 8, wherein the controller is further configured to stop an operation for changing the adjustment factor of the available voltage level when the switching condition is not satisfied for the preset time interval. [10] A method of controlling a motor drive device including a dual inverter configured to drive a motor according to a motor drive mode, the method comprising: Determining whether to perform flux weakening control for adjusting an output voltage level of the dual inverter according to an available voltage level of the dual inverter when a switching condition of the motor drive mode is satisfied; and Perform flux weakening control by adjusting the available voltage level of the dual inverter for a specified time interval. [11] The method according to claim 10, wherein the preset time interval corresponds to a time interval from a time point at which the switching condition of the motor drive mode is satisfied to a time point at which the motor drive mode is switched. [12] The method of claim 10, wherein the motor drive mode comprises: a first drive mode in which a neutral point of the motor is formed and the motor is driven by a first inverter of first and second inverters included in the dual inverter; and a second drive mode in which the neutral point of the motor is not formed and the motor is driven via the first and second inverters. [13] The method according to claim 12, wherein the switching condition of the motor drive mode corresponds to a switching condition from the second drive mode to the first drive mode. [14] The method of claim 13, wherein determining comprises determining execution of the flux weakening control when the available voltage level exceeds a voltage limit level of the first drive mode. [15] The method of claim 13, wherein determining includes determining switching from the second mode to the first mode without performing the flux weakening control when the available voltage level is less than or equal to a voltage limit level of the first mode. [16] The method of claim 12, wherein the available voltage level varies depending on a DC terminal voltage of the dual inverter and is set higher in the second drive mode than in the first drive mode. [17] The method of claim 10, wherein adjusting comprises adjusting the output voltage level by changing an adjustment factor of the available voltage level for the preset time interval when the flux weakening control is performed. [18] The method of claim 17, further comprising stopping an operation for changing the adjustment factor of the available voltage level if the switching condition is not met for the predetermined time interval.

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