Motor driving apparatus and control method thereof

Abstract

The invention relates to a motor driving apparatus and a control method thereof. The motor driving device includes: a motor having a plurality of windings; a dual inverter including a first inverter connected to a first end of the plurality of windings and a second inverter connected to a second end 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 driving mode; and a controller configured to determine whether to execute the field weakening control according to an available voltage level of the dual inverter when a switching condition of the motor driving mode is satisfied, and execute the field weakening control by linearly adjusting an output voltage level of the dual inverter within a preset time interval in which the field weakening control is executed.

Description

Technical Field

[0001] The present invention relates to a motor drive device and a control method thereof, and more particularly, to a motor drive device and a control method thereof for stabilizing torque output from a motor when switching a motor drive mode. Background Art

[0002] Recently, due to the demand for motor driving technology capable of improving system efficiency while covering both low power ranges and high power ranges with one motor, technology that can drive a motor in two different motor driving modes using two inverters and a mode switching switch has been introduced.

[0003] Here, one of the different motor driving modes is a closed end winding (CEW) mode in which one inverter drives the motor using a Y-type connection structure, and the other is an open end winding (OEW) mode in which two inverters drive the motor.

[0004] Generally, the switching between the CEW mode and the OEW mode can be determined by the reverse magnetic flux of the motor and the torque of the motor. However, when the motor drive mode is switched at the time point when the switching condition is satisfied, the torque output from the motor becomes unstable because the available voltage of the inverter decreases rapidly. To solve this problem, there is a method of adjusting the switching reference line of the maximum efficiency, but this method will lead to a decrease in the efficiency of the motor drive device.

[0005] The information disclosed in the above Background section is intended to assist in understanding the background of the invention and should not be regarded as an admission that the information constitutes any part of the prior art. Summary of the invention

[0006] The present invention aims to stabilize the torque output from a motor when switching the motor driving mode by linearly adjusting the output voltage level of an inverter within a preset time interval when switching the motor driving mode.

[0007] The technical problems solved by the present invention are not limited to the above-mentioned technical problems, and those skilled in the art to which the present invention belongs will be able to clearly understand other technical problems not mentioned from the following description.

[0008] In order to solve the above technical problems, a motor drive device may include: a motor having multiple windings; a dual inverter, including a first inverter connected to a first end of the multiple windings and a second inverter connected to a second end of the multiple windings, and configured to drive the motor through at least one of the first inverter or the second inverter according to a motor drive mode; and a controller, configured to: when a switching condition of the motor drive mode is met, determine whether to perform flux weakening control according to an available voltage level of the dual inverter, and perform flux weakening control by linearly adjusting the output voltage level of the dual inverter within a preset time interval for performing flux weakening control.

[0009] In one embodiment, the preset time interval may correspond to a time interval from a time point when the switching condition of the motor driving mode is satisfied to a time point when the motor driving mode is switched.

[0010] In one embodiment, the motor drive device may further include a plurality of mode switching switches, the first ends of the plurality of mode switching switches are connected to the second ends of the plurality of windings, and the second ends of the plurality of mode switching switches are connected to each other. The motor drive mode may include: a first drive mode, in which the plurality of mode switching switches are turned on, and the motor is driven by the first inverter of the first inverter and the second inverter; a second drive mode, in which the plurality of mode switching switches are turned off, and the motor is driven by the first inverter and the second inverter.

[0011] In one embodiment, the switching condition of the motor driving mode may correspond to the switching condition of switching from the second driving mode to the first driving mode.

[0012] In one embodiment, when the available voltage level is greater than the voltage limit level of the first driving mode, the controller may adjust the output voltage level to the voltage limit level of the first driving mode within a preset time interval and then switch from the second driving mode to the first driving mode.

[0013] In one embodiment, when the available voltage level is less than or equal to the voltage limit level of the first driving mode, the controller may switch from the second driving mode to the first driving mode without performing flux weakening control.

[0014] In one embodiment, the available voltage level may vary according to the DC terminal voltage of the dual inverter, and may be set higher in the second driving mode than in the first driving mode.

[0015] In one embodiment, when performing flux weakening control, the controller may adjust the output voltage level by changing the regulation factor of the available voltage level within a preset time interval.

[0016] In one embodiment, when the switching condition is not satisfied within a preset time interval, the controller may stop the operation of changing the adjustment factor of the available voltage level.

[0017] In addition, in order to solve the above-mentioned technical problems, a method for controlling a motor drive device including a dual inverter configured to drive a motor according to a motor drive mode may include: when a switching condition of the motor drive mode is met, determining whether to perform magnetic field weakening control based on the available voltage level of the dual inverter; and performing magnetic field weakening control by linearly adjusting the output voltage level of the dual inverter within a preset time interval for performing magnetic field weakening control.

[0018] In one embodiment, the preset time interval may correspond to a time interval from a time point when the switching condition of the motor driving mode is satisfied to a time point when the motor driving mode is switched.

[0019] In one embodiment, the motor driving mode may include: a first driving mode, in which the neutral point of the motor is formed and the motor is driven by the first inverter of the first inverter and the second inverter included in the dual inverter; a second driving mode, in which the neutral point of the motor is not formed and the motor is driven by the first inverter and the second inverter.

[0020] In one embodiment, the switching condition of the motor driving mode may correspond to a switching condition from the second driving mode to the first driving mode.

[0021] In one embodiment, determining whether to perform the flux weakening control may include: determining to perform the flux weakening control when the available voltage level is greater than the voltage limit level of the first driving mode.

[0022] In one embodiment, determining whether to perform the flux weakening control may include: when the available voltage level is less than or equal to the voltage limit level of the first driving mode, determining to switch from the second driving mode to the first driving mode without performing the flux weakening control.

[0023] In one embodiment, the available voltage level may vary according to the DC terminal voltage of the dual inverter, and may be set higher in the second driving mode than in the first driving mode.

[0024] In one embodiment, adjusting the output voltage level of the dual inverter may include adjusting the output voltage level by changing an adjustment factor of an available voltage level within a preset time interval when performing magnetic field weakening control.

[0025] In one embodiment, the method may further include: when the switching condition is not satisfied within a preset time interval, stopping the operation of changing the adjustment coefficient of the available voltage level.

[0026] According to the present invention, the torque output from the motor when the motor driving mode is switched can be stabilized by linearly adjusting the output voltage level of the inverter within a preset time interval when the motor driving mode is switched.

[0027] Effects that can be obtained from the present invention are not limited to the above-mentioned effects, and other effects that are not mentioned will be clearly understood from the following description by those skilled in the art to which the present invention pertains.

[0028] The methods and apparatus of the present invention have other features and advantages, which will be apparent from, or will be described in more detail in, the accompanying drawings and the following detailed description incorporated herein, which together serve to explain the specific principles of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 is a circuit diagram of a motor drive device according to an embodiment of the present invention;

[0030] Figure 2 is a schematic diagram for describing a switching motor driving mode according to an embodiment of the present invention;

[0031] Figure 3 is a flowchart for describing a method of controlling a motor drive device according to an embodiment of the present invention; and

[0032] Figure 4 and Figure 5 is a schematic diagram for describing a process of switching a motor driving mode according to an embodiment of the present invention.

[0033] It should be understood that the accompanying drawings are not necessarily drawn to scale, but are appropriately simplified drawings of various features presented to illustrate the basic principles of the present invention. The specific design features of the present invention included in this article (including, for example, specific size, direction, position and shape) will be determined in part by the specific environment to be applied and used.

[0034] In the drawings, like reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. DETAILED DESCRIPTION

[0035] Hereinafter, the embodiments disclosed in this specification will be described in detail with reference to the attached drawings, and regardless of the figure numbers, the same figure numbers represent the same or similar components, and their repeated descriptions will be omitted. The suffixes "module" and "unit" of the components used in the following description are given or used interchangeably in consideration of the convenience of writing the specification, and they themselves do not have different meanings or functions from each other. In addition, when describing the embodiments disclosed in this specification, when it is determined that the detailed description of the relevant known technology may obscure the main purpose of the embodiments disclosed in this specification, its detailed description will be omitted. In addition, the attached drawings are only for the convenience of understanding the embodiments disclosed in this specification, and it should be understood that the technical spirit disclosed in this specification is not limited by the attached drawings, and all modified forms, equivalent forms or alternative forms included in the spirit and technical scope of the present invention are included in the attached drawings.

[0036] Terms including ordinal numbers such as first or second may be used to describe various components, but these components are not limited by the terms. These terms are used only for the purpose of distinguishing one component from another.

[0037] When a component is described as being "connected" or "engaged" to another component, it should be understood that it can be directly connected or engaged to the other component, or other components can be arranged therebetween. On the other hand, when a component is described as being "directly connected" or "directly engaged" to another component, it should be understood that there are no other components therebetween.

[0038] Unless the context clearly dictates otherwise, a singular expression includes a plural form.

[0039] In the specification, it should be understood that terms such as “include” or “have” are intended to indicate the presence of the features, values, steps, operations, components, parts or a combination thereof described in the specification, but do not exclude the possibility of the presence or addition of one or more other features, values, steps, operations, components, parts or a combination thereof.

[0040] In addition, the unit or control unit included in the name of the motor control unit (MCU) or the hybrid control unit (HCU) is a term widely used to name a controller for controlling a specific function of the vehicle, and does not mean a general functional unit. For example, each controller may include a communication device for communicating with another controller for controlling the responsible function, a memory for storing an operating system, logic instructions, input / output information, etc., and one or more processors for performing determinations, calculations, decisions, etc. required for controlling the responsible function.

[0041] Figure 1 is a circuit diagram of a motor driving device according to an embodiment of the present invention.

[0042] refer to Figure 1 , a motor driving apparatus according to an embodiment of the present invention may include dual inverters 10 and 20 , a motor 30 having each of a plurality of windings C1 , C2 , and C3 corresponding to one phase of a plurality of phases, a mode switching unit 40 , a battery 50 , and a controller 100 .

[0043] 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 end 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 may 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 the motor demand output (i.e., the torque command of the motor), the DC terminal voltage of the inverters 10 and 20 (i.e., the voltage of the battery), the phase current of the motor and the motor angle.

[0044] 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 the plurality of phases of the motor 30, so that an electrical connection may be formed. 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 the connection node of the two switching elements S11 and S12 may be connected to one end of the winding C1 of one phase in the motor 30, so that an alternating current (AC) corresponding to one of the plurality of phases is input or output. Similarly, the second branch 12 may include two switching elements S13 and S14 connected in series between the two ends of the battery 50, and the connection node of the two switching elements S13 and S14 may be connected to one end of the winding C2 of one phase in the motor 30, so that an alternating current corresponding to one of the plurality of phases is input or output. In addition, the third branch 13 may include two switching elements S15 and S16 connected in series between the two ends of the battery 50, and the connection node of the two switching elements S15 and S16 can be connected to one end of the winding C3 of one phase in the motor 30, thereby inputting or outputting alternating current corresponding to one phase among the multiple phases.

[0045] 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 plurality of phases of the motor 30, so that an electrical connection may be formed. More specifically, the first branch 21 may include 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 as to input or output the AC corresponding to one of the plurality of phases. Similarly, the second branch 22 may include two switching elements S23 and S24 connected in series between the two 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 as to input or output the AC corresponding to one of the plurality of phases. In addition, the third branch 23 may include two switching elements S25 and S26 connected in series between the two ends of the battery 50, and the connection node of the two switching elements S25 and S26 can be connected to the other end of the winding C3 of one phase in the motor 30, thereby inputting or outputting alternating current corresponding to one phase of the multiple phases.

[0046] One end of the plurality of mode switching switches S31, S32 and S33 can be connected to the plurality of windings C1, C2 and C3 respectively, and the other end thereof can be connected to each other. The plurality of mode switching switches S31, S32 and S33 can adopt various switching devices known in the art, for example, metal oxide semiconductor field effect transistors (MOSFETs), insulated gate bipolar transistors (IGBTs), thyristors and relays.

[0047] Although Figure 1 Although not shown, the motor drive device may further include a so-called Y-type capacitor, which connects two capacitors in series between a positive (+) DC terminal and a negative (-) DC terminal and grounds a connection node between the capacitors.

[0048] 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 based on the required output of the motor 30 through pulse width modulation control.

[0049] In addition, 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 driving mode. The motor driving mode may include a first driving mode and a second driving mode. In this case, the first driving mode may be referred to as a "CEW mode" and the second driving mode may be referred to as an "OEW mode".

[0050] The dual inverters 10 and 20 may drive the motor 30 through at least one of the first inverter 10 or the second inverter 20 according to the motor driving mode. More specifically, when the CEW mode is performed, the controller 100 may control the mode switching switches S31, S32, and S33 to be turned on so that the other ends of the plurality of windings C1 to C3 form a neutral point, and the motor 30 is driven by the first inverter 10 of the two inverters 10 and 20. In contrast, when the OEW mode is performed, the controller 100 may control the mode switching switches S31, S32, and S33 to be turned off so that the other ends of the plurality of windings C1 to C3 do not form a neutral point, and the motor 30 is driven by the two inverters 10 and 20.

[0051] Figure 2 is a schematic diagram for describing a switching motor driving mode according to an embodiment of the present invention.

[0052] refer to Figure 2 , shows an operating point map of the motor, which displays an output limit curve L1 of the CEW mode, an output limit curve L2 of the OEW mode, and a mode switching reference line L3 based on an efficiency map.

[0053] The output limit curves L1 and L2 may indicate the output torque limit value of the motor for each motor speed (e.g., RPM) in each motor drive mode. In at least a portion of the RPM region, the output limit curve L2 may have an output limit greater than or equal to the output limit curve L1, and the output limit curves L1 and L2 may be set in consideration of durability, heat generation, current controllability, etc. of the motor and inverter.

[0054] The mode switching reference line L3 based on the efficiency map (not shown) may correspond to the boundary line between the high efficiency area of ​​the CEW mode and the high efficiency area of ​​the OEW mode. The efficiency map may include information on the mode with higher efficiency between the CEW mode and the OEW mode in each combination of the torque and the reverse magnetic flux of the motor, and may be in the form of a table according to the implementation scheme. For example, the efficiency map may be obtained based on the results of the motor losses caused by the motor speed and torque measured by experiments for each DC terminal voltage of the inverter in each motor drive mode. In this case, the reverse magnetic flux of the motor may be inversely proportional to the DC terminal voltage of the inverter (i.e., the voltage of the battery) and directly proportional to the speed of the motor.

[0055] According to the embodiment, the mode switching reference line L3 may have a shape such as L3' according to the specifications of the motor driving device. Figure 2 The mode switching reference lines L3 and L3 ′ shown in are exemplary, and the present invention is not necessarily limited thereto.

[0056] In order to switch the motor drive mode according to the mode switching reference line L3, the controller 100 can refer to the efficiency map and bidirectionally switch the CEW mode and the OEW mode according to the torque command value and the reverse magnetic flux value of the motor. In this case, the reverse magnetic flux value can be calculated based on the torque command of the motor, the DC terminal voltage of the inverter, and the required speed of the motor. According to the embodiment, the controller 100 can correct the mode switching reference line by considering factors such as the output limit value and hysteresis of the motor drive mode. In this case, the motor drive mode is switched based on the corrected mode switching reference line and the torque command value and the reverse magnetic flux value of the motor.

[0057] Hereinafter, a method of controlling a motor driving apparatus will be described, which stabilizes torque output from a motor when switching a motor driving mode by linearly adjusting an output voltage level of an inverter within a preset time interval when switching a motor driving mode.

[0058] Figure 3 is a flowchart for describing a method of controlling a motor drive device according to an embodiment of the present invention.

[0059] refer to Figure 3 , the controller 100 may control the driving of the motor 30 through at least one of the first inverter 10 or the second inverter 20 according to the motor driving mode (step S101). As described above, the motor driving mode may include a CEW mode and an OEW mode. The CEW mode may correspond to a mode in which a 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 inverter 10 and the second inverter 10. In contrast, the OEW mode may correspond to a mode in which a plurality of mode switching switches S31, S32, and S33 are turned off, and the motor 30 is driven by the first inverter 10 and the second inverter 20.

[0060] Thereafter, the controller 100 may determine whether the switching condition of the motor drive mode is satisfied based on the reverse magnetic flux of the motor 30 and the torque of the motor 30 (step S102). In an embodiment, the switching condition of the motor drive mode may correspond to the switching condition from the OEW mode to the CEW mode. When the switching condition from the OEW mode to the CEW mode is not satisfied (No in step S102), the controller 100 may maintain the execution of the OEW mode in step S101.

[0061] When the switching condition of the motor drive mode is satisfied (i.e., when the switching condition from the OEW mode to the CEW mode is satisfied) (Yes in step S102), the controller 100 may determine whether to perform flux weakening control according to the available voltage level of the dual inverters 10 and 20 (step S103). More specifically, the controller 100 may determine whether to perform flux weakening control according to whether the available voltage level of the dual inverters 10 and 20 is greater than the voltage limit level of the CEW mode.

[0062] Here, field weakening control refers to a control scheme for increasing the speed range of the motor under given current and voltage limits in a motor drive. More specifically, when the motor drive condition exceeds a certain torque or a certain speed, the output voltage of the inverter (10, 20) exceeds the available voltage. By appropriately adjusting the output voltage to within the available voltage through field weakening control, the speed range of the motor can be expanded. This control is based on the property that the magnetic flux is proportional to the output voltage and inversely proportional to the torque.

[0063] When the output voltage level is higher than the available voltage level, the flux weakening control is performed. The area around the operating point where switching occurs between the CEW mode and the OEW mode corresponds to the flux weakening control area of ​​the CEW mode, and corresponds to the non-flux weakening control area of ​​the OEW mode.

[0064] Therefore, in this embodiment, the flux weakening control is performed to prevent the torque shock caused by the rapid decrease of the available voltage level in the mode switching interval from the OEW mode to the CEW mode. In other words, when it is determined that the mode switching is performed in the OEW mode, the available voltage level in the OEW mode is forcibly reduced to the available voltage level suitable for the CEW mode within a preset time interval, even if the current operating point is not in the region where the flux weakening control is required. By reducing the available voltage level, the output voltage level can be reduced to a level suitable for the CEW mode before entering the CEW mode.

[0065] In this case, the available voltage level of the dual inverters 10 and 20 may vary according to the DC terminal voltage of the dual inverters 10 and 20 (i.e., the voltage of the battery), and may be set to be higher in the OEW mode than in the CEW mode. For example, the available voltage level of the CEW mode may correspond to Vdc (the voltage of the battery), and the available voltage level of the OEW mode may correspond to Vdc (the voltage of the battery).

[0066] When the available voltage level of the dual inverters 10 and 20 is less than or equal to the voltage limit level of the CEW mode (No in step S103 ), the controller 100 may switch the OEW mode to the CEW mode without performing flux weakening control (step S106 ).

[0067] On the contrary, when the available voltage level of the dual inverters 10 and 20 is greater than the voltage limit level of the CEW mode (yes in step S103), the controller 100 can linearly adjust the output voltage level of the dual inverters 10 and 20 to the voltage limit level of the CEW mode within a preset time interval for performing weak magnetic control (steps S104 and S105), and then switch the OEW mode to the CEW mode (step S106). In this case, the preset time interval may correspond to the time interval from the time point when the switching condition of the motor drive mode is satisfied to the time point when the motor drive mode is switched. In an embodiment, the preset time interval may correspond to the time interval from the time point when the switching condition from the OEW mode to the CEW mode is satisfied to the time point when the CEW mode is executed.

[0068] More specifically, when the available voltage level of the dual inverters 10 and 20 is greater than the voltage limit level of the CEW mode (Yes in step S103), the controller 100 may adjust the output voltage level of the dual inverters 10 and 20 by changing the adjustment coefficient of the available voltage level of the dual inverters 10 and 20 (step S104). When the OEW mode is executed, the available voltage level of the dual inverters 10 and 20 may correspond to "Regulation factor for available voltage levels".

[0069] Thereafter, the controller 100 may determine whether a preset time interval has elapsed (step S105 ).

[0070] When the preset time interval elapses (Yes in step S105 ), the controller 100 may switch the OEW mode to the CEW mode (step S106 ).

[0071] Before the preset time interval elapses (No in step S105 ), the controller 100 may determine whether the switching condition of the motor driving mode (ie, the switching condition from the OEW mode to the CEW mode) is not satisfied (step S107 ).

[0072] When the switching condition of the motor drive mode is satisfied (No in step S107 ), the controller 100 may maintain the execution of the flux weakening control (step S104 ).

[0073] When the switching condition of the motor drive mode is not satisfied within the preset time interval (yes in step S107), the controller 100 may stop the operation of changing the adjustment coefficient of the available voltage level (step S108). For example, the controller 100 may change the adjustment coefficient of the available voltage level to "1" when the switching condition of the motor drive mode is not satisfied. Therefore, the controller 100 may prevent the weak magnetic control from being performed in the area where the switching condition of the motor drive mode is not satisfied.

[0074] At the same time, unlike the implementation scheme of performing weak magnetic control within a preset time interval, a method of performing weak magnetic control when the current reverse magnetic flux of the motor is within a range close to the mode switching baseline can be considered, but according to this method, since the current reverse magnetic flux of the motor can be continuously within a range close to the mode switching baseline, the efficiency of the motor drive device will be reduced.

[0075] Figure 4 and Figure 5 is a schematic diagram for describing a process of switching a motor driving mode according to an embodiment of the present invention.

[0076] refer to Figure 4 , at time point ta, the controller 100 may determine that the switching condition from the OEW mode to the CEW mode is satisfied. The controller 100 may linearly reduce the adjustment coefficient of the available voltage level from "1.0" to "x" within the interval (i.e., the preset time interval) from time point ta to time point tb. Thereafter, at time point tb, the controller 100 may nonlinearly increase the adjustment coefficient of the available voltage level from "x" to "1.0", and switch the motor drive mode from the OEW mode to the CEW mode.

[0077] In this case, the adjustment coefficient of the available voltage level can be adjusted in the direction of reducing the available voltage level to the voltage limit level of the CEW mode within the preset time interval. "x" and the preset time interval can be set differently according to the implementation scheme. In addition, when the preset time interval for performing the weak magnetic control increases, the change of the motor torque decreases, but the efficiency of the motor drive device will decrease.

[0078] refer to Figure 5 , a schematic diagram showing the operation points of the dual inverters 10 and 20 moving along the constant torque curve Te within a preset time interval (the time interval from the time point ta to the time point tb). At the time point ta, the operation points of the dual inverters 10 and 20 are located on the constant torque curve Te, and within the preset time interval (the time interval from the time point ta to the time point tb), the operation points of the dual inverters 10 and 20 can move linearly to the voltage limit of the CEW mode.

[0079] At the same time, the present invention described above can be implemented as a computer-readable code on a medium having a program recorded thereon. Computer-readable recording media include any type of recording media storing data that can be read by a computer system. Examples of computer-readable media include hard disk drives (HDDs), solid-state drives (SSDs), silicon disk drives (SDDs), read-only memories (ROMs), random access memories (RAMs), CD-(ROMs), magnetic tapes, floppy disks, optical data storage devices, and the like. Therefore, the above detailed description should not be interpreted as limiting in all aspects, but should be interpreted as exemplary. The scope of the present invention is determined by a reasonable interpretation of the appended claims, and all modifications within the equivalent scope of the present invention are included within the scope of the present invention.

Claims

1. A motor drive device, comprising: 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 or the second inverter according to a motor driving mode; as well as A controller is configured to: when the switching condition of the motor drive mode is met, determine whether to perform weakening control for adjusting the output voltage level of the dual inverter according to the available voltage level of the dual inverter, and perform the weakening control by adjusting the available voltage level of the dual inverter within a preset time interval.

2. The motor drive device according to claim 1, wherein: The preset time interval corresponds to a time interval from a time point when a switching condition of the motor driving mode is satisfied to a time point when the motor driving mode is switched.

3. The motor drive device according to claim 1, further comprising a plurality of mode switching switches, wherein first ends of the plurality of mode switching switches are respectively connected to second ends of the plurality of windings, and second ends of the plurality of mode switching switches are connected to each other, in, The motor driving modes include: a first driving mode, wherein the plurality of mode switching switches are turned on, and the motor is driven by the first inverter of the first inverter and the second inverter; and A second driving mode, wherein the plurality of mode switching switches are turned off, and the motor is driven by the first inverter and the second inverter.

4. The motor drive device according to claim 3, wherein: The switching condition of the motor driving mode corresponds to a switching condition for switching from the second driving mode to the first driving mode.

5. The motor drive device according to claim 4, wherein: The controller is further configured to: When the available voltage level is greater than the voltage limit level of the first driving mode, adjusting the output voltage level to the voltage limit level of the first driving mode within a preset time interval; 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 driving mode to the first driving mode without performing flux weakening control when the available voltage level is less than or equal to the voltage limit level of the first driving mode.

7. The motor driving device according to claim 3, wherein: The available voltage level varies according to the DC terminal voltage of the dual inverter and is set to be higher in the second driving mode than in the first driving mode.

8. The motor driving device according to claim 1, wherein: The controller is further configured to adjust the output voltage level by changing the adjustment coefficient of the available voltage level within a preset time interval when performing the flux weakening control.

9. The motor drive device according to claim 8, wherein: The controller is further configured to stop the operation of changing the adjustment coefficient of the available voltage level when the switching condition is not satisfied within a preset time interval.

10. A method for controlling a motor drive device, the motor drive device comprising a dual inverter, the dual inverter being configured to drive a motor according to a motor drive mode, the method comprising: When the switching condition of the motor drive mode is satisfied, determining whether to perform a flux weakening control for adjusting the output voltage level of the dual inverter according to the available voltage level of the dual inverter; Field weakening control is performed by adjusting the available voltage level of the dual inverters at preset time intervals.

11. The method according to claim 10, wherein: The preset time interval corresponds to a time interval from a time point when a switching condition of the motor driving mode is satisfied to a time point when the motor driving mode is switched.

12. The method according to claim 10, wherein: The motor driving modes include: a first driving mode in which a neutral point of the motor is formed and the motor is driven by a first inverter of a first inverter and a second inverter included in a dual inverter; and A second driving mode in which a neutral point of the motor is not formed and the motor is driven by the first inverter and the second inverter.

13. The method according to claim 12, wherein: The switching condition of the motor driving mode corresponds to a switching condition from the second driving mode to the first driving mode.

14. The method according to claim 13, wherein: Determining whether to perform the flux weakening control for adjusting the output voltage level of the dual inverter includes: when the available voltage level is greater than the voltage limit level of the first driving mode, determining to perform the flux weakening control.

15. The method according to claim 13, wherein: Determining whether to perform flux weakening control for adjusting the output voltage level of the dual inverter includes: when the available voltage level is less than or equal to the voltage limit level of the first driving mode, determining to switch from the second driving mode to the first driving mode without performing flux weakening control.

16. The method according to claim 12, wherein: The available voltage level varies according to the DC terminal voltage of the dual inverter and is set to be higher in the second driving mode than in the first driving mode.

17. The method according to claim 10, wherein: Adjusting the available voltage level of the dual inverter includes adjusting the output voltage level by changing an adjustment coefficient of the available voltage level within a preset time interval when performing magnetic field weakening control.

18. The method according to claim 17, further comprising: When the switching condition is not satisfied within the preset time interval, the operation of changing the adjustment coefficient of the available voltage level is stopped.

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