Motor driving apparatus and control method thereof

Abstract

A motor driving apparatus comprises: a power supply unit for supplying direct current power; a plurality of switching elements for converting the direct current power supplied from the power supply unit into three-phase alternating current power, the plurality of switching elements including upper switching elements and lower switching elements; a resistive element connected between a lower node of the lower switching elements and the power supply unit; and a control unit for generating, in a first mode, a voltage command vector on the basis of an average phase current determined while operating in a second mode, wherein in the second mode, the control unit controls the plurality of switching elements such that all of the plurality of switching elements are not turned on or off at a central point of a switching period, and determines the average phase current by sampling a current flowing via the resistive element at the central point of the switching period.

Description

Motor driving device and its control method

[0001] The disclosed invention relates to a motor driving device and a control method thereof that detects a phase current flowing in a motor and drives the motor according to the detected phase current.

[0002] Typically, motor drives convert direct current into multi-phase alternating current and apply it to the motor. To properly control the motor, a method is used to measure the phase current applied to the motor and control the current applied to the motor accordingly using pulse width modulation (PWM).

[0003] Recently, the space vector concept has been introduced and the space vector pulse width modulation (SVPWM) method is being used to control the power applied to the motor based on the three-phase current detected by one or more resistive elements.

[0004] However, when controlling the power applied to the motor using the space vector pulse width modulation (SVPWM) method, there was a problem in that the accurate three-phase current could not be measured from the current flowing through one or more resistance elements when the voltage command vector was located in the dead band, which is an area where the three-phase current cannot be detected.

[0005] In addition, when controlling the power applied to the motor using the space vector pulse width modulation (SVPWM) method, there was a problem in that the current flowing in one or more resistive elements could not be sampled in the zero vector section, which is a section in which multiple switching elements are all turned on or all turned off during the switching cycle, and thus the accurate phase current could not be measured from the current flowing in one or more resistive elements.

[0006] One aspect of the disclosed invention can provide a motor driving device and a control method thereof capable of restoring a phase current by using a current flowing in a resistance element.

[0007] A motor driving device according to the invention comprises: a power supply unit supplying direct current power; a plurality of switching elements converting direct current power supplied from the power supply unit into three-phase alternating current power, the plurality of switching elements including upper switching elements and lower switching elements; a resistor element connected between a lower node of the lower switching elements and the power supply unit; and a control unit generating a voltage reference vector based on an average phase current determined while operating in a second mode in a first mode; wherein, in the second mode, the control unit controls the plurality of switching elements so that none of the plurality of switching elements are turned on or none of the plurality of switching elements are turned off at a central point of a switching cycle, and samples a current flowing through the resistor element at a central point of the switching cycle to determine the average phase current.

[0008] A control method for a motor driving device according to the idea of ​​the present disclosure comprises a power supply unit supplying DC power, a plurality of switching elements converting the DC power supplied from the power supply unit into three-phase AC power, a plurality of switching elements including upper switching elements and lower switching elements, and a resistance element connected between a lower node of the lower switching elements and the power supply unit, the control method for a motor driving device comprising: in a first mode, generating a voltage command vector based on an average phase current; in a second mode, controlling the plurality of switching elements so that none of the plurality of switching elements are turned on or none of the plurality of switching elements are turned off at a central point of a switching cycle; and in the second mode, sampling a current flowing through the resistance element at a central point of a switching cycle to determine an average phase current.

[0009] According to one aspect of the present disclosure, there is a better effect of enabling more precise motor drive control by restoring the current flowing in the resistance element to a phase current.

[0010] According to one aspect of the present disclosure, there is a better effect of enabling more precise motor drive control by restoring the current flowing through the resistance element to a phase current in multiple modes.

[0011] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0012] Figure 1 illustrates a block diagram for explaining control operations between a power conversion system and other components.

[0013] Figure 2 illustrates a simplified circuit diagram of a motor drive device according to one embodiment.

[0014] FIG. 3 is a drawing for explaining the operation of an internal block of a control unit and a motor driving device according to one embodiment.

[0015] Figure 4 is a diagram for explaining space vector-based pulse width modulation.

[0016] Fig. 5 is a diagram for explaining a phase current detection method based on space vector-based pulse width modulation.

[0017] FIGS. 6 and 7 are drawings for explaining the operation of a switching element for driving a motor according to one embodiment.

[0018] Fig. 8 is a flowchart illustrating a method for controlling a switching element by a motor driving device according to one embodiment.

[0019] FIG. 9 is a diagram illustrating a method of modulating a voltage command vector during a first mode operation, according to one embodiment.

[0020] FIG. 10 shows an operating waveform of a switching element during a first mode operation, according to one embodiment.

[0021] FIGS. 11 to 13 illustrate the operating waveform of a switching element and the current waveform flowing through a resistive element during a second mode operation according to one embodiment.

[0022] FIG. 14 is a diagram illustrating a method for determining an average phase current during a second mode operation according to one embodiment.

[0023] FIG. 15 is a diagram showing that, according to one embodiment, the average phase current of the actual phase current during the second mode operation and the average phase current obtained by sampling the current flowing through the resistance element are consistent.

[0024] The embodiments described in this specification and the configurations illustrated in the drawings are merely preferred examples of the disclosed invention, and there may be various modified examples that can replace the embodiments and drawings of this specification at the time of filing of this application.

[0025] The terminology used herein is for the purpose of describing embodiments only and is not intended to limit and / or restrict the disclosed invention.

[0026] For example, in this specification, a singular expression may include a plural expression unless the context clearly indicates otherwise.

[0027] In this document, each of the phrases "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" may include any one of the items listed together in that phrase, or all possible combinations thereof.

[0028] The term "and / or" includes any combination of a plurality of related described elements or any one of a plurality of related described elements.

[0029] Terms such as "first," "second," or "first" or "second" may be used simply to distinguish one component from another and do not qualify the components in any other respect (e.g., importance or order).

[0030] When a component (e.g., a first component) is referred to as being "coupled" or "connected" to another component (e.g., a second component), with or without the terms "functionally" or "communicatively," it means that the component can be connected to the other component directly (e.g., wired), wirelessly, or through a third component.

[0031] The terms "include" or "have" are intended to specify the presence of a feature, number, step, operation, component, part or combination thereof described in this document, but do not preclude the presence or addition of one or more other features, numbers, steps, operations, components, parts or combinations thereof.

[0032] When a component is said to be “connected,” “coupled,” “supported,” or “in contact with” another component, this includes not only cases where the components are directly connected, coupled, supported, or in contact, but also cases where the components are indirectly connected, coupled, supported, or in contact through a third component.

[0033] When we say that a component is "on" another component, this includes not only cases where the component is in contact with the other component, but also cases where there is another component between the two components.

[0034] *In addition, terms such as "~part", "~device", "~block", "~absence", and "~module" may refer to a unit that processes at least one function or operation. For example, the terms may refer to at least one hardware such as an FPGA (field-programmable gate array) / ASIC (application specific integrated circuit), at least one software stored in memory, or at least one process processed by a processor.

[0035] Below, a motor driving device according to various embodiments is specifically described with reference to the attached drawings.

[0036] Figure 1 illustrates a block diagram of a power conversion system.

[0037] Referring to FIG. 1, the power conversion system may include a commercial power source (200), a motor drive device (10), and / or a motor (300).

[0038] A commercial AC power source (200) can supply AC current (is) for the operation of the motor drive device (10) to the motor drive device (10).

[0039] In Fig. 1, the commercial AC power source (200) and the motor drive device (10) are shown as being connected in single phase, but the commercial AC power source (200) can supply AC current (is) to the motor drive device (10) in three phases.

[0040] For example, a commercial AC power source (200) can supply AC current (is) as a three-phase current to a motor drive device (10).

[0041] The motor driving device (10) may include a power supply unit (11), a plurality of switching elements (12), a resistance element (150) and / or a control unit (100).

[0042] The power supply unit (11) can convert AC current (is) supplied from a commercial AC power source (200) into DC power.

[0043] The power supply unit (11) may include an EMI filter, a power factor correction circuit (PFC) converter, and / or an output capacitor to convert the AC current (is) supplied from a commercial AC power source (200) into DC power.

[0044] The EMI filter can filter out noise included in the AC current (is) supplied from a commercial AC power source (200). The power factor correction circuit (PFC) can generate a signal that can maximize the power factor of the power supplied to the motor (300) so that the maximum power can be supplied to the motor (300) using the AC current (is) supplied from the commercial AC power source (200). The converter can convert the AC current (is) supplied from the commercial AC power source (200) into DC power through a switching operation. The output capacitor can supply DC power to the motor drive device (10) by alternately charging and discharging the DC power converted by the converter. Through this, the power supply unit (11) can supply DC power to a plurality of switching elements (12).

[0045] A plurality of switching elements (12) can receive direct current power from a power supply unit (11). The plurality of switching elements (12) can convert the direct current power supplied from the power supply unit (11) into three-phase alternating current power and supply it to the motor (300). The three-phase alternating current power can include three-phase currents (ia, ib, ic, see FIG. 2 below) supplied to the motor (300) from the plurality of switching elements (12). The three-phase currents (ia, ib, ic) can include a first phase current (ia), a second phase current (ib), and a third phase current (ic).

[0046] Although in FIG. 1, the motor drive device (10) is illustrated as supplying AC power to the motor (300) in three phases, one aspect of the present disclosure is that the motor drive device (10) can supply AC power to the motor (300) in a single phase. However, for convenience of explanation, the following description will describe the motor drive device (10) as supplying AC power to the motor (300) in three phases.

[0047] A resistance element (150) is connected between the power supply unit (11) and a plurality of switching elements (12), so that a current (idc) flowing between the power supply unit (11) and the plurality of switching elements (12) can be applied.

[0048] The resistance element (150) may include a shunt resistor. The shunt resistor may be a resistor for detecting three-phase currents (ia, ib, ic) supplied to the motor (300) from the plurality of switching elements (12). A method of detecting the three-phase currents (ia, ib, ic) supplied to the motor (300) from the plurality of switching elements (12) using the current (idc) flowing in the shunt resistor and controlling the driving of the motor (300) according to the detected three-phase currents (ia, ib, ic) may be referred to as a shunt algorithm. The shunt algorithm may be classified into a 1-shunt method, a 2-shunt method, and a 3-shunt method depending on the number of shunt resistors, and an embodiment according to the present disclosure may employ a 1-shunt method, a 2-shunt method, or a 3-shunt method. However, for convenience of explanation, the following description will focus on the 1-shunt method.

[0049] The control unit (100) can generate a switching control signal (S) for driving the switching element (12) using the current (idc) flowing in the resistance element (150). For example, the control unit (100) can sample the current (idc) flowing in the resistance element (150) to determine the three-phase currents (ia, ib, ic) supplied from the plurality of switching elements (12) to the motor (300), and can generate a switching control signal (S) for driving the plurality of switching elements (12) using the determined three-phase currents (ia, ib, ic). The plurality of switching elements (12) can operate according to the switching control signal (S) to control the three-phase currents (ia, ib, ic) supplied to the motor (300), and the motor (300) can be driven according to the three-phase currents (ia, ib, ic) supplied by the plurality of switching elements (12).

[0050] The motor (300) has a stator and a rotor, and a phase current (ia, ib, ic) is applied to the coils of the stator to cause the rotor to rotate. The motor (300) may include a surface-mounted permanent-magnet synchronous motor (SMPMSM), an interior permanent magnet synchronous motor (IPMSM), and a synchronous reluctance motor (Synrm).

[0051] Figure 2 illustrates a simplified circuit diagram of a motor drive device according to one embodiment.

[0052] Referring to FIG. 2, the plurality of switching elements (12) may include a plurality of upper switching elements (Sa1, Sb1, Sc1). The plurality of switching elements (12) may include a plurality of lower switching elements (Sa2, Sb2, Sc2).

[0053] The plurality of upper switching elements (Sa1, Sb1, Sc1) may include a first upper switching element (Sa1), a second upper switching element (Sb1), and a third upper switching element (Sc1).

[0054] The plurality of lower switching elements (Sa2, Sb2, Sc2) may include a first lower switching element (Sa2), a second lower switching element (Sb2), and a third lower switching element (Sc2).

[0055] The first upper switching element (Sa1) and the first lower switching element (Sa2) may be referred to as a first phase switching element (Sa, see FIG. 6).

[0056] *The second upper switching element (Sb1) and the second lower switching element (Sb2) may be referred to as a second phase switching element (Sb, see FIG. 6).

[0057] The third upper switching element (Sc1) and the first lower switching element (Sc2) may be referred to as a third phase switching element (Sc, see FIG. 6).

[0058] In the case of the first phase switching element (Sa), when the first upper switching element (Sa1) and the first lower switching element (Sa2) are turned on at the same time, the current flowing through the first upper switching element (Sa1) and the second lower switching element (Sa2) may increase rapidly, which may cause loss or failure of the first upper switching element (Sa1) and the first lower switching element (Sa2). In addition, in the case of the first phase switching element (Sa), when the first upper switching element (Sa1) and the first lower switching element (Sa2) are turned off at the same time, the current flowing through the first upper switching element (Sa1) and the second lower switching element (Sa2) may decrease rapidly, which may cause loss or failure of the first upper switching element (Sa1) and the first lower switching element (Sa2).

[0059] In this way, in order to prevent loss or failure of the switching elements of each phase, the upper switching element and the lower switching element among the switching elements of each phase cannot be turned on or off simultaneously. That is, in the section where the upper switching element among the switching elements of each phase is turned on, the lower switching element is turned off, and in the section where the upper switching element is turned off, the lower switching element is turned on.

[0060] Hereinafter, turning on the first phase switching element (Sa) means turning on the first upper switching element (Sa1) and turning off the first lower switching element (Sa1), and turning off the first phase switching element (Sa) means turning off the first upper switching element (Sa1) and turning on the first lower switching element (Sa2).

[0061] In addition, in the following, turning on the second phase switching element (Sb) means turning on the second upper switching element (Sb1) and turning off the second lower switching element (Sb1), turning off the second phase switching element (Sb) means turning off the second upper switching element (Sb1) and turning on the second lower switching element (Sb2), turning on the third phase switching element (Sc) means turning on the third upper switching element (Sc1) and turning off the third lower switching element (Sc1), and turning off the third phase switching element (Sc) means turning off the third upper switching element (Sc1) and turning on the third lower switching element (Sc2).

[0062] Each of the plurality of switching elements (12) may include an IGBT switch, a GaN switch, a SiC switch, etc.

[0063] The resistance element (150) can be connected between the lower node (N) of the plurality of lower switching elements (Sa1, Sb1, Sc1) and the power supply (11).

[0064] A current (idc) flowing between the power supply (11) and the plurality of switching elements (12) may flow through the resistance element (150). The current (idc) flowing between the power supply (11) and the plurality of switching elements (12) may be a rippled current.

[0065] The control unit (100) can generate a switching control signal (S) for driving a plurality of switching elements (12) using a current (idc) flowing through a resistance element (150), and supply the generated switching control signal (S) to the plurality of switching elements (12).

[0066] A plurality of switching elements (12) are driven according to a switching control signal (S), and the DC power supplied from the power supply unit (11) can be converted into three-phase current (ia, ib, ic) according to the driving of the plurality of switching elements (12). The three-phase current (ia, ib, ic) converted according to the driving of the plurality of switching elements (12) can be supplied to the motor (300).

[0067] FIG. 3 is a drawing for explaining the operation of an internal block of a control unit and a motor driving device according to one embodiment.

[0068] Referring to FIG. 3, the control unit (100) may include a speed control unit (110), a current control unit (120), a first axis converter unit (130), a switching control signal generation unit (140), a second axis converter (190), a current restoration unit (180), and / or an average phase current determination unit (170).

[0069] The average phase current determination unit (170) can determine the three-phase average phase current (icomp) by sampling the current flowing through the resistance element (150). The three-phase average phase current (icomp) can include a first average phase current (ia, avg, see FIG. 10) which is the average phase current of the first phase, a second average phase current (ib, avg, not shown) which is the average phase current of the second phase, and a third average phase current (ic, avg, see FIG. 10) which is the average phase current of the third phase.

[0070] The first phase may be a phase corresponding to the first upper switching element (Sa1) and the first lower switching element (Sa1), the second phase may be a phase corresponding to the second upper switching element (Sb1) and the second lower switching element (Sb2), and the third phase may be a phase corresponding to the third upper switching element (Sc1) and the third lower switching element (Sc2).

[0071] The average phase current determination unit (170) can transmit the determined three-phase average phase current (icomp) to the current restoration unit (180). For example, when the average phase current determination unit (170) determines the first average phase current (ia, avg, see FIG. 10), the determined first average phase current (ia, avg) can be transmitted to the current restoration unit (180), when the second average phase current (ib, avg) is determined, the determined second average phase current (ib, avg) can be transmitted to the current restoration unit (180), and when the third average phase current (ic, avg) is determined, the determined third average phase current (ic, avg) can be transmitted to the current restoration unit (180).

[0072] The current restoration unit (180) can obtain the three-phase restored phase current (irec) using the three-phase average phase current (icomp) received from the average phase current (icomp). The three-phase restored phase current (irec) can include a first-phase restored phase current restored from the first average phase current (ia, avg) received from the average phase current determination unit (170), a second-phase restored phase current restored from the second average phase current (ib, avg) received from the average phase current determination unit (170), and a third-phase restored phase current restored from the third average phase current (ib, avg) received from the average phase current determination unit (170).

[0073] The current restoration unit (180) obtaining the three-phase restoration phase current (irec) may mean detecting the phase current. Hereinafter, detecting the phase current by sampling the current (idc) flowing through the resistance element (150) means sampling the current (idc) flowing through the resistance element (150) to determine the average phase current (icomp), and obtaining the three-phase restoration phase current (irec) using the determined average phase current (icomp).

[0074] The current restoration unit (180) can transmit the acquired three-phase restoration phase current (irec) to the second-axis converter (190). For example, when the current restoration unit (180) acquires the first-phase restoration phase current, it can transmit the acquired first-phase restoration phase current to the second-axis converter (190), when the current restoration unit (180) acquires the second-phase restoration phase current, it can transmit the acquired second-phase restoration phase current to the second-axis converter (190), and when the current restoration unit (180) acquires the third-phase restoration phase current, it can transmit the acquired third-phase restoration phase current to the second-axis converter (190).

[0075] The second axis converter (190) can convert the three-phase restoration phase current (irec) received from the current restoration unit (180) into a two-phase current of the stationary coordinate system, and then convert the converted two-phase current of the stationary coordinate system into a two-phase current (id, iq) of the rotating coordinate system. For example, the second axis converter (190) can convert the first restoration phase current, the second restoration phase current, and the third restoration phase current received from the current restoration unit (180) into a two-phase current of the stationary coordinate system, and then convert the converted two-phase current of the stationary coordinate system into a two-phase current (id, iq) of the rotating coordinate system.

[0076] The second axis converter (190) can transmit the two-phase current (id, iq) of the rotating coordinate system to the current control unit (120).

[0077] The speed control unit (110) can generate current commands (id*, iq*). Although not shown in the drawing, the speed control unit (110) can generate current commands (id*, iq*) through PI control of the three-phase restored phase current (irec) restored from the current restoration unit (180).

[0078] The speed control unit (110) can generate the current command (id*) of the d-axis as 0. Meanwhile, the speed control unit (110) can further include a limiter that limits the level of the current command (iq*) of the q-axis so that it does not exceed the allowable range.

[0079] The speed control unit (110) can transmit the generated current command (id*, iq*) to the current control unit (120).

[0080] The current control unit (120) can generate voltage commands (Vd*, Vq*) using the two-phase currents (id, iq) of the rotating coordinate system received from the second axis converter (190) and the current commands (id*, iq*) received from the speed control unit (110). For example, the current control unit (120) can perform PI control based on the difference between the two-phase currents (id, iq) of the rotating coordinate system and the current commands (id* iq*) and generate voltage commands (Vd*, Vq*). Meanwhile, the current control unit (120) may further include a limiter that limits the level of the voltage commands (Vd*, Vq*) so that they do not exceed the allowable range.

[0081] The current control unit (120) can transmit the generated voltage command (Vd*, Vq*) to the first axis conversion unit (130).

[0082] The first axis conversion unit (130) can generate a voltage command vector (V*) using the voltage command (Vd*, Vq*) received from the current control unit (120). For example, the first axis conversion unit (130) can convert the voltage command (Vd*, Vq*) into an axis to generate a voltage command vector (V*) of a three-phase stationary coordinate system.

[0083] The voltage reference vector (V*) may include three-phase output reference vectors. For example, the voltage reference vector (V*) may include a first-phase output reference vector, a second-phase output reference vector, and a third-phase output reference vector.

[0084] The first axis conversion unit (130) can transmit the generated voltage command vector (V*) to the switching control signal generation unit (140).

[0085] The switching control signal generation unit (140) can generate a switching control signal (S) according to a pulse width modulation (PWM) method based on the voltage command vector (V*) received from the first axis conversion unit (130).

[0086] The switching control signal generation unit (140) may include a first pulse width modulation unit (141) and a second pulse width modulation unit (142).

[0087] The first pulse width modulation unit (141) can generate a first switching control signal (S1) to be supplied to a plurality of switching elements (12) when operating in the first mode described later.

[0088] The second pulse width modulation unit (142) can generate a second switching control signal (S2) to be supplied to a plurality of switching elements (12) when operating in the second mode described later.

[0089] The switching control signal generation unit (140) can supply the generated switching control signal (S) to a plurality of switching elements (12). In addition, the switching control signal (S) can be converted into a gate driving signal in a gate driving unit (not shown) and supplied to each of the plurality of switching elements (12).

[0090] A switching control signal (S) is applied to a plurality of switching elements (12) to drive the plurality of switching elements (12), and by driving the plurality of switching elements (12), the direct current power supplied from the power supply unit (11, see Fig. 1) can be converted into a three-phase alternating current power. The three-phase alternating current power can include three-phase currents (ia, ib, ic) as described above.

[0091] The motor (300) can be driven by three-phase currents (ia, ib, ic). Therefore, since the driving control of the motor (300) is performed according to the three-phase currents (ia, ib, ic) supplied to the motor (300) from a plurality of switching elements (12), it is necessary to detect the three-phase currents (ia, ib, ic) supplied to the motor (300) from a plurality of switching elements (12).

[0092] Below, an embodiment for detecting three-phase currents (ia, ib, ic) supplied from multiple switching elements (12) to a motor (300) is described.

[0093] Figure 4 is a diagram for explaining space vector-based pulse width modulation.

[0094] Fig. 5 is a diagram for explaining a phase current detection method based on space vector-based pulse width modulation.

[0095] FIGS. 6 and 7 are drawings for explaining the operation of a switching element for driving a motor according to one embodiment.

[0096] Referring to FIG. 4, the control unit (100) can generate a switching control signal (S) using a space vector-based pulse width modulation (SPWM) method.

[0097] The control unit (100) can generate a voltage reference vector (V*) by synthesizing two effective voltage vectors and a zero voltage vector. The effective voltage vector can include a first effective voltage vector (V1), a second effective voltage vector (V2), a third effective voltage vector (V3), a fourth effective voltage vector (V4), a fifth effective voltage vector (V5), and a sixth effective voltage vector (V6).

[0098] The zero voltage vector may include a first zero voltage vector (V0) and a second zero voltage vector (V7).

[0099] When a plurality of switching elements (12) are driven according to the first effective voltage vector (V1), the first phase switching element (Sa) is turned on, and the second phase switching element (Sb) and the third phase switching element (Sc) are turned off (100).

[0100] When a plurality of switching elements (12) are driven according to the second effective voltage vector (V2), the first phase switching element (Sa) and the second phase switching element (Sb) are turned on, and the third phase switching element (Sc) is turned off (110).

[0101] When multiple switching elements (12) are driven according to the first zero voltage vector (V0), the first phase switching element (Sa), the second phase switching element (Sb), and the third phase switching element (Sc) are all turned off (000).

[0102] When multiple switching elements (12) are driven according to the second zero voltage vector (V7), the first phase switching element (Sa), the second phase switching element (Sb), and the third phase switching element (Sc) are all turned on (111).

[0103] As illustrated in FIG. 4, the control unit (100) can synthesize a voltage command vector (V*) by synthesizing a first effective voltage vector (V1) and a second effective voltage vector (V2), and can generate a switching control signal (S) according to the synthesized voltage command vector (V*).

[0104] In this case, the plurality of switching elements (12) can operate according to the first effective vector (V1) or the second effective vector (V2) in one switching cycle. For example, when the plurality of switching elements (12) operate according to the voltage reference vector (V*) that is a composite of the first effective voltage vector (V1) and the second effective voltage vector (V2), one switching cycle can include a section (100) in which the first phase switching element (Sa) is turned on, the second phase switching element (Sb) and the third phase switching element (Sc) are turned off, and a section (110) in which the first phase switching element (Sa) and the second phase switching element (Sb) are turned on, and the third phase switching element (Sc) is turned off.

[0105] The voltage reference vector (V*) may be located in one of the first sector (Sec1), the second sector (Sec2), the third sector (Sec3), the fourth sector (Sec4), the fifth sector (Sec5), and the sixth sector (Sec6).

[0106] When synthesizing the first effective voltage vector (V1) and the second effective voltage vector (V2), the voltage command vector (V*) can be located in the first sector (Sec1).

[0107] When the voltage reference vector (V*) is located in the first region (A0), two phase currents among the three phase currents (ia, ib, ic) cannot be detected.

[0108] When the voltage reference vector (V*) is located in the second region (A1), one of the three phase currents (ia, ib, ic) cannot be detected.

[0109] When the voltage reference vector (V*) is located in the third area (A2), all three-phase currents (ia, ib, ic) can be detected.

[0110] The first region (A0) and the second region (A1), which are regions where some of the three-phase currents (ia, ib, ic) cannot be detected, may be referred to as dead zones or dead bands.

[0111] Referring to FIG. 6, the control unit (100) can detect a first phase current (ia) when a plurality of switching elements (12) operate according to a first effective voltage vector (V1). The control unit (100) can detect a third phase current (ic) when a plurality of switching elements (12) operate according to a second effective voltage vector (V2).

[0112] The control unit (100) cannot detect the phase current when the plurality of switching elements (12) operate according to the zero voltage vector. For example, the control unit (100) cannot detect the phase current when the plurality of switching elements (12) operate according to the first zero voltage vector (V0). For another example, the control unit (100) cannot detect the phase current when the plurality of switching elements (12) operate according to the second zero voltage vector (111).

[0113] Referring to FIG. 6, the operation of a plurality of switching elements (12) that operate according to a switching control signal (S) generated based on a voltage command vector (V*) generated by synthesizing a first effective voltage vector (V1), a second effective voltage vector (V2), and a zero voltage vector is shown.

[0114] In the switching cycle (Tsw), at T0 / 4, which is a cycle that includes the starting point (t2) of the switching cycle (Tsw) or the ending point (t3) of the switching cycle (Tsw), the first phase switching element (Sa), the second phase switching element (Sb), and the third phase switching element (Sc) can all be turned off according to the first zero voltage vector (V0).

[0115] At T1 / 2, the first phase switching element (Sa) can be turned on and the second phase switching element (Sb) and the third phase switching element (Sc) can be turned off according to the first effective voltage vector (V1).

[0116] At T1 / 2, the control unit (100) can detect the first phase current (ia) from the current (idc) flowing through the resistance element (150) by driving a plurality of switching elements (12) according to the first effective voltage vector (V1).

[0117] At T2 / 2, the first phase switching element (Sa) and the second phase switching element (Sb) can be turned on and the third phase switching element (Sc) can be turned off according to the second effective voltage vector (V2).

[0118] At T2 / 2, the control unit (100) can detect the third phase current (ic) from the current (idc) flowing through the resistance element (150) by driving a plurality of switching elements (12) according to the second effective voltage vector (V2).

[0119] At T0 / 2, since multiple switching elements (12) are driven according to the first zero voltage vector (V0) or the second zero voltage vector (V7), the phase current cannot be detected from the current (idc) flowing through the resistance element (150).

[0120] That is, the control unit (100) can detect the phase current in a section in which multiple switching elements (12) are driven according to the effective voltage vector during the switching period (Tsw), and cannot detect the phase current in a section in which multiple switching elements (12) are driven according to the zero voltage vector during the switching period (Tsw).

[0121] *The control unit (100) can detect the phase current in a section in which a plurality of switching elements (12) are driven according to an effective voltage vector. For example, the control unit (100) can detect the first phase current (ia) in a first section (T1) in which the first phase switching element (Sa) is turned on and the second phase switching element (Sb) and the third phase switching element (Sc) are turned off according to a first effective vector (V1). In addition, the control unit (100) can detect the third phase current (ic) in a second section (T2) in which the first phase switching element (Sa) and the second phase switching element (Sb) are turned on and the third phase switching element (Sc) is turned off according to a second effective voltage vector (V2).

[0122] However, if the section in which multiple switching elements (12) are driven is short according to the effective voltage vector, a problem may occur in detecting the phase current through the current (idc) flowing through the resistance element (150).

[0123] Referring to Fig. 7, the phase current must be detected by sampling the current (idc) flowing through the resistance element (150) after the setting time, dead time, and A / D conversion time due to the ringing phenomenon caused by the plurality of switching elements (12).

[0124] Therefore, the period in which multiple switching elements (12) are driven according to the effective voltage vector must be longer than the minimum time (Tmin) for sampling the current (idc) flowing through the resistance element (150) to detect the phase current.

[0125] The minimum time (Tmin) may be a preset time depending on the performance of the motor driving device (10). Hereinafter, the minimum time (Tmin) is described as a preset time (Tmin).

[0126] At T0 / 4, which is a period including the central point (t1) of the switching period (Tsw), the first phase switching element (Sa), the second phase switching element (Sb), and the third phase switching element (Sc) can all be turned on according to the second zero voltage vector (V7).

[0127] Since the first section (T1) is shorter than the preset time (Tmin), the first phase current (ia) cannot be detected in the first section (T1).

[0128] Since the second section (T2) is also shorter than the preset time (Tmin), the third phase current (ic) cannot be detected in the second section (T1).

[0129] Therefore, if the period in which multiple switching elements (12) are driven according to the effective voltage vector is shorter than the preset time (Tmin), it is necessary to modulate the voltage command vector (V*) so that the period in which multiple switching elements (12) are driven according to the effective voltage vector is longer than the preset time (Tmin). This will be described below.

[0130] Fig. 8 is a flowchart illustrating a method for controlling a switching element by a motor driving device according to one embodiment.

[0131] FIG. 9 is a diagram illustrating a method of modulating a voltage command vector during a first mode operation, according to one embodiment.

[0132] FIG. 10 shows an operating waveform of a switching element during a first mode operation, according to one embodiment.

[0133] Referring to Fig. 8, the control unit (100) can start operation in the first mode (S1).

[0134] The first mode may include a mode in which an average phase current (ia, avg, ib, avg, ic, avg) is determined from a current (idc) flowing through a resistor element (150), a voltage reference vector (V*) is generated based on the determined average phase current (ia, avg, ib, avg, ic, avg) (S2, see FIG. 8), and a switching control signal (S) is generated according to the generated voltage reference vector (V*) to drive a plurality of switching elements (12). In addition, the first mode may include a mode in which the voltage reference vector (V*) is modulated so that a time for which the plurality of switching elements (12) are driven according to the effective voltage vector is longer than the preset time (Tmin) when a period in which the plurality of switching elements (12) are driven according to the effective voltage vector is shorter than a preset time (Tmin) for sampling the current (idc) flowing through the resistor element (150). Below, the first mode is described through FIGS. 7 to 10.

[0135] Referring to FIG. 7, according to one embodiment, in the first mode, the control unit (100) can control a plurality of switching elements (12) so that the first phase switching element (Sa), the second phase switching element (Sb), and the third phase switching element (Sc) are turned on at the center point (t1) of the switching cycle (Tsw).

[0136] According to the above, the first phase switching element (Sa) being turned on may include the first upper switching element (Sa1) being turned on and the first lower switching element (Sa2) being turned off, and the first phase switching element (Sa) being turned off may include the first upper switching element (Sa1) being turned off and the first lower switching element (Sa2) being turned off. The second phase switching element (Sb) being turned on may include the second upper switching element (Sb1) being turned on and the second lower switching element (Sb2) being turned off, and the second phase switching element (Sb) being turned off may include the second upper switching element (Sb1) being turned off and the second lower switching element (Sb2) being turned on. The third phase switching element (Sc) being turned on may include the third upper switching element (Sc1) being turned on and the third lower switching element (Sc2) being turned off, and the third phase switching element (Sc) being turned off may include the third upper switching element (Sc1) being turned off and the third lower switching element (Sc2) being turned on.

[0137] According to one embodiment, in the first mode, the control unit (100) can control the plurality of switching elements (12) so that the first phase switching element (Sa), the second phase switching element (Sb), and the third phase switching element (Sc) are turned off at the starting point (t2) of the switching cycle (Tsw) and the ending point (t3) of the switching cycle (Tsw).

[0138] Referring to FIGS. 7 and 8, according to one embodiment, in the first mode, the control unit (100) can control the plurality of switching elements (12) so that the first period (T1) is longer than the preset time (Tmin) based on the fact that the first period (T1) in which the first phase switching element (Sa) is on and the second phase switching element (Sb) and the third phase switching element (Sc) are off is shorter than the preset time (Tmin) (S3, S4).

[0139] According to one embodiment, in the first mode, the control unit (100) can control the plurality of switching elements (12) so that the second period (T2) is longer than the preset time (Tmin) based on the fact that the second period (T2) in which the first phase switching element (Sa) and the second switching element (Sb) are on and the third phase switching element (Sc) is off in the switching cycle (Tsw) is shorter than the preset time (Tmin) (S5, S6).

[0140] Referring to FIG. 9, the fact that the first section (T1) and the second section (T2) are shorter than the preset time (Tmin) may mean that the voltage command vector (V*) is located in the first area (A0), and the fact that one of the first section (T1) and the second section (T2) is shorter than the preset time (Tmin) may mean that the voltage command vector (V*) is located in the second area (A1).

[0141] In the first mode, the first pulse width modulation unit (140, see FIG. 3) can generate a first switching control signal (S1) for modulating the voltage command vector (V*) so that both the first section (T1) and the second section (T2) are longer than the preset time (Tmin) when the voltage command vector (V*) is located in the second area (A1) and one of the first section (T1) and the second section (T2) is shorter than the preset time (Tmin). In addition, in the first mode, the first pulse width modulation unit (141) can generate a first switching control signal (S1) for modulating the voltage command vector (V*) so that both the first section (T1) and the second section (T2) are longer than the preset time (Tmin) when the voltage command vector (V*) is located in the first area (A0) and the first section (T1) and the second section (T2) are shorter than the preset time (Tmin).

[0142] In the first mode, the first pulse width modulation unit (141) modulating the voltage reference vector (V*) may include injecting a voltage into the voltage reference vector (V*) through an injection voltage vector (Vm) and compensating the voltage through a compensation voltage vector (Vs) for compensating for the amount of the injected voltage vector (Vs). This may be expressed as a PWM shift method or a minimum voltage injection (MVI) method.

[0143] Referring to FIG. 10, FIG. 10 illustrates that in the first mode, a plurality of switching elements (12) are driven by modulating the voltage command vector (V*) based on at least one of the first section (T1) and the second section (T2) being shorter than a preset time (Tmin) so that both the first section (T1) and the second section (T2) are longer than a preset time (Tmin).

[0144] Through this, the phase current (ia, ib, ic) can be detected by sampling the current (idc) flowing through the resistance element (150) in a section where multiple switching elements (12) are driven according to the effective voltage vector.

[0145] *In order to detect the phase current (ia, ib, ic) that matches the actual phase current (e.g., ia, real, ic, real) by sampling the current (idc) flowing through the resistor element (150), the current (idc) flowing through the resistor element (150) must be sampled to obtain an accurate average phase current (ia, avg, ib, avg, ic, avg). In order to obtain an accurate average phase current (ia, avg, ib, avg, ic, avg), the phase current (ia, ib, ic) must be sampled at a point where the fundamental component of the phase current (ia, ib, ic) can be sampled during the switching period (Tsw), and generally, the point where the fundamental component of the phase current (ia, ib, ic) can be sampled is the starting point (t2), the center point (t1), or the end point (t3) of the switching period (Tsw).

[0146] However, in the first mode, when the motor driving device (10) is driven, as shown in FIG. 10, a plurality of switching elements (12) are driven according to a zero voltage vector at the starting point (e.g., t21, t22) of the switching cycle (Tsw), the center point (e.g., t11, t12) of the switching cycle (Tsw), and the end point (e.g., t31, t32) of the switching cycle (Tsw), so that the current (idc) flowing through the resistance element (150) in the above section cannot be sampled, and the accurate average phase current (ia, avg, ib, avg, ic, avg) cannot be obtained.

[0147] Therefore, in the first mode, it is not possible to obtain an accurate average phase current (ia, avg, ib, avg, ic, avg), which may result in a decrease in the performance of the drive control of the motor (300). Hereinafter, a second mode for accurately obtaining the average phase current used in the first mode will be described.

[0148] FIGS. 11 to 13 illustrate the operating waveform of a switching element and the current waveform flowing through a resistive element during a second mode operation according to one embodiment.

[0149] Referring to FIGS. 11 to 13, according to one embodiment, in the second mode, the control unit (100) can control the plurality of switching elements (12) such that not all of the plurality of switching elements (12) are turned on or not all of the switching elements (12) are turned off at the central point (t1) of the switching cycle (Tsw).

[0150] Referring to FIG. 11, according to one embodiment, in the second mode, the control unit (100) can control a plurality of switching elements (12) such that the first phase switching element (Sa) is turned off at the center point (t1) of the switching cycle (Tsw), and the second phase switching element (Sb) and the third switching element (Sc) are turned on.

[0151] According to one embodiment, in the second mode, the control unit (100) can control the plurality of switching elements (12) such that the first phase switching element (Sa) is turned on at the starting point (t2) of the switching period (Tsw) and the ending point (t3) of the switching period (Tsw), and the second phase switching element (Sb) and the third phase switching element (Sc) are turned on at the starting point (t2) of the switching period (Tsw) and the ending point (t3) of the switching period (Tsw).

[0152] According to one embodiment, in the second mode, the control unit (100) can sample the current (idc) flowing through the resistance element (150) at the center point (t1) of the switching cycle (Tsw) to determine the first average phase current (ia, avg), which is the first phase average phase current corresponding to the first phase switching element (Sa).

[0153] Additionally, in the second mode, the control unit (100) can sample the current (idc) flowing through the resistance element (150) at the starting point (t2) of the switching cycle (Tsw) or the ending point (t3) of the switching cycle (Tsw) to determine the first average phase current (ia, avg), which is the first phase average phase current corresponding to the first phase switching element (Sa).

[0154] Referring to FIG. 12, according to one embodiment, in the second mode, the control unit (100) can control the plurality of switching elements (12) so that the second phase switching element (Sb) is turned off at the center point (t1) of the switching cycle (Tsw), and the first phase switching element (Sa) and the third switching element (Sc) are turned on.

[0155] According to one embodiment, in the second mode, the control unit (100) can control the plurality of switching elements (12) such that the second phase switching element (Sb) is turned on at the starting point (t2) of the switching cycle (Tsw) and the ending point (t3) of the switching cycle (Tsw), and the first phase switching element (Sa) and the third phase switching element (Sc) are turned on at the starting point (t2) of the switching cycle (Tsw) and the ending point (t3) of the switching cycle (Tsw).

[0156] According to one embodiment, in the second mode, the control unit (100) can sample the current (idc) flowing through the resistance element (150) at the center point (t1) of the switching cycle (Tsw) to determine the second average phase current (ib, avg), which is the second average phase current corresponding to the second phase switching element (Sb).

[0157] Additionally, in the second mode, the control unit (100) can sample the current (idc) flowing through the resistance element (150) at the starting point (t2) of the switching cycle (Tsw) or the ending point (t3) of the switching cycle (Tsw) to determine the second average phase current (ib, avg), which is the second average phase current corresponding to the second phase switching element (Sb).

[0158] Referring to FIG. 13, according to one embodiment, in the second mode, the control unit (100) can control the plurality of switching elements (12) so that the third phase switching element (Sc) is turned off at the center point (t1) of the switching cycle (Tsw), and the first phase switching element (Sa) and the second switching element (Sb) are turned on.

[0159] According to one embodiment, in the second mode, the control unit (100) can control the plurality of switching elements (12) such that the third phase switching element (Sc) is turned on at the starting point (t2) of the switching cycle (Tsw) and the ending point (t3) of the switching cycle (Tsw), and the first phase switching element (Sa) and the second phase switching element (Sb) are turned on at the starting point (t2) of the switching cycle (Tsw) and the ending point (t3) of the switching cycle (Tsw).

[0160] According to one embodiment, in the second mode, the control unit (100) can sample the current (idc) flowing through the resistance element (150) at the center point (t1) of the switching cycle (Tsw) to determine a third average phase current (ic, avg), which is a third phase average phase current corresponding to the third phase switching element (Sc).

[0161] Additionally, in the second mode, the control unit (100) can sample the current (idc) flowing through the resistance element (150) at the starting point (t2) of the switching cycle (Tsw) or the ending point (t3) of the switching cycle (Tsw) to determine the third average phase current (ic, avg), which is the third phase average phase current corresponding to the third phase switching element (Sc).

[0162] According to the present disclosure, there is a better effect of obtaining an accurate average phase current by sampling the current (idc) flowing through the resistance element (150) at the starting point (t2), the middle point (t1) or the ending point (t3) of the switching cycle (Tsw).

[0163] FIG. 14 is a diagram illustrating a method for determining an average phase current during a second mode operation according to one embodiment.

[0164] FIG. 15 is a diagram showing that, according to one embodiment, the average phase current of the actual phase current during the second mode operation and the average phase current obtained by sampling the current flowing through the resistance element are consistent.

[0165] Referring to FIGS. 14 and 15, according to various embodiments, in the second mode, the control unit (100) can determine the average phase current during two switching cycles (e.g., Tsw1, Tsw2).

[0166] In one embodiment, the control unit (100) can determine the first average phase current (ia, avg) by sampling the current (idc) flowing through the resistance element (150) at the center point (t11) of the first switching cycle (Tsw1).

[0167] In one embodiment, the control unit (100) can determine the third average phase current (ic, avg) by sampling the current (idc) flowing through the resistance element (150) at the center point (t12) of the second switching cycle (Tsw2), which is the next switching cycle following the first switching cycle (Tsw1).

[0168] The control unit (100) can determine all average phase currents of the three phases based on the first average phase current (ia, avg) determined in the first switching cycle (Tsw1) and the third average phase current (ic, avg) determined in the second switching cycle (Tsw2).

[0169] For example, when the control unit (100) obtains the first average phase current (ia, avg) and the third average phase current (ic, avg), the control unit (100) can determine the second average phase current (ib, avg) by using the fact that the sum of the first average phase current (ia, avg), the second average phase current (ib, avg), and the third average phase current (ic, avg) is 0.

[0170] In the present disclosure, it has been described that the first average phase current (ia, avg) is determined in the first switching period (Tsw1) and the third average phase current (ic, avg) is determined in the second switching period (Tsw2), but the method for determining the average phase current is not limited thereto. For example, when the first average phase current (ia, avg) is determined in the first switching period (Tsw1) and a plurality of switching elements (12) are driven as illustrated in FIG. 12 in the second switching period (Tsw2), the second average phase current (ib, avg) can be determined in the second switching period (Tsw2).

[0171] Referring again to FIG. 8, in one embodiment, the control unit (100) may initiate operation in the second mode in response to operating in the first mode for a first predetermined period of time (S7, S8).

[0172] As described above, in the second mode, the control unit (100) can sample the current (idc) flowing through the resistance element (150) at the center point (t1) of the switching cycle (Tsw) (S9). In addition, the control unit (100) can determine the average phase current based on the sampled current (idc) (S10).

[0173] In one embodiment, the control unit (100) may operate in the first mode in response to operating in the second mode for a second predetermined period of time (S11).

[0174] The first predetermined time may be longer than the second predetermined time.

[0175] According to one embodiment, in the first mode, the control unit (100) can generate a voltage command vector (V*) based on the average phase current (ia, avg, ib, avg, ic, avg) determined while operating in the second mode.

[0176] According to the present disclosure, while operating in the first mode, the motor can operate in the second mode at predetermined intervals to obtain an accurate average phase current, and when operating in the first mode again, the motor can generate a voltage command vector using the accurate average phase current obtained in the second mode, thereby providing a better effect of improving the drive control performance of the motor.

[0177] A motor driving device according to one embodiment of the present disclosure includes: a power supply unit for supplying DC power; a plurality of switching elements for converting the DC power supplied from the power supply unit into three-phase AC power, the plurality of switching elements including upper switching elements and lower switching elements; a resistor element connected between a lower node of the lower switching elements and the power supply unit; and a control unit for generating a voltage reference vector based on an average phase current determined while operating in a second mode in a first mode; wherein, in the second mode, the control unit controls the plurality of switching elements so that none of the plurality of switching elements are turned on or none of the plurality of switching elements are turned off at a central point of a switching cycle, and samples a current flowing through the resistor element at a central point of the switching cycle to determine the average phase current.

[0178] The upper switching elements include a first upper switching element, a second upper switching element, and a third upper switching element, and in the second mode, the control unit can control the plurality of switching elements so that the first upper switching element is turned off at a central point of a switching cycle and the second upper switching element and the third upper switching element are turned on.

[0179] In the second mode, the control unit can control the plurality of switching elements so that the first upper switching element is turned on at the start point of the switching cycle and the end point of the switching cycle, and the second upper switching element and the second upper switching element are turned off at the start point of the switching cycle and the end point of the switching cycle.

[0180] In the second mode, the control unit can determine a first average phase current corresponding to the first upper switching element by sampling the current flowing through the resistive element at a central point of the switching cycle.

[0181] In the second mode, the control unit can determine a third average phase current corresponding to the third upper switching element by sampling the current flowing through the resistive element at the center point of the next switching cycle of the switching cycle, and can determine the average phase current based on the first average phase current and the third average phase current.

[0182] The upper switching elements include a first upper switching element, a second upper switching element, and a third upper switching element, and in the first mode, the control unit can control the plurality of switching elements so that the first upper switching element, the second upper switching element, and the third upper switching element are turned on at a central point of the switching cycle.

[0183] In the first mode, the control unit can control the plurality of switching elements so that the first upper switching element, the second upper switching element, and the third upper switching element are turned off at the start point of the switching cycle and the end point of the switching cycle.

[0184] In the first mode, the control unit can control the plurality of switching elements so that the first period is longer than the preset time based on the fact that the first upper switching element is on and the second upper switching element and the third upper switching element are off in the switching cycle is shorter than the preset time.

[0185] In the first mode, the control unit can control the plurality of switching elements so that the second period is longer than the preset time based on the fact that the second period in which the first upper switching element and the second upper switching element are on and the third upper switching element is off in the switching cycle is shorter than the preset time.

[0186] The control unit operates in the second mode in response to operating in the first mode for a first predetermined time, and operates in the first mode in response to operating in the second mode for a second predetermined time, wherein the first predetermined time may be longer than the second predetermined time.

[0187] A method for controlling a motor driving device according to one embodiment of the present disclosure includes a power supply unit for supplying DC power, a plurality of switching elements for converting the DC power supplied from the power supply unit into three-phase AC power, a plurality of switching elements including upper switching elements and lower switching elements, and a resistance element connected between a lower node of the lower switching elements and the power supply unit, the method comprising: in a first mode, generating a voltage command vector based on an average phase current; in a second mode, controlling the plurality of switching elements so that none of the plurality of switching elements are turned on or none of the plurality of switching elements are turned off at a central point of a switching cycle; and in the second mode, sampling a current flowing through the resistance element at a central point of the switching cycle to determine the average phase current.

[0188] The upper switching elements may include a first upper switching element, a second upper switching element, and a third upper switching element, and controlling the plurality of switching elements in the second mode may include controlling the plurality of switching elements such that the first upper switching element is off at a central point of a switching cycle and the second upper switching element and the third upper switching element are on.

[0189] Controlling the plurality of switching elements in the second mode may include controlling the plurality of switching elements so that the first upper switching element is turned on at a starting point of the switching period and an ending point of the switching period, and the second upper switching element and the second upper switching element are turned off at a starting point of the switching period and an ending point of the switching period.

[0190] Determining the average phase current by sampling the current flowing through the resistive element at a central point of the switching cycle in the second mode may include determining the first average phase current of the phase corresponding to the first upper switching element by sampling the current flowing through the resistive element at a central point of the switching cycle.

[0191] In the second mode, the method may further include determining a third average phase current corresponding to the third upper switching element by sampling the current flowing through the resistive element at the center point of the next switching cycle of the switching cycle, and determining the average phase current based on the first average phase current and the third average phase current.

[0192] The upper switching elements include a first upper switching element, a second upper switching element, and a third upper switching element, and the control method of the motor driving device may further include controlling a plurality of switching elements so that the first upper switching element, the second upper switching element, and the third upper switching element are turned on at a central point of a switching cycle in the first mode.

[0193] It may further include controlling a plurality of switching elements so that the first upper switching element, the second upper switching element, and the third upper switching element are turned off at the start point of the switching cycle and the end point of the switching cycle in the first mode.

[0194] In the first mode, the first upper switching element is turned on and the second upper switching element and the third upper switching element are turned off in the switching cycle, and the first section is controlled so that the first section is longer than the preset time, based on the first section being shorter than the preset time.

[0195] In the first mode, the second section in which the first upper switching element and the second upper switching element are on and the third upper switching element is off is shorter than the preset time, and controlling the plurality of switching elements so that the second section is longer than the preset time may be further included.

[0196] In response to operating in the first mode for a first predetermined period of time, operating in the second mode; and further comprising operating in the first mode in response to operating in the second mode for a second predetermined period of time, wherein the first predetermined period of time may be longer than the second predetermined period of time.

[0197] Meanwhile, the disclosed embodiments may be implemented in the form of a recording medium storing computer-executable instructions. The instructions may be stored in the form of program code, and when executed by a processor, may generate program modules to perform the operations of the disclosed embodiments. The recording medium may be implemented as a computer-readable recording medium.

[0198] Computer-readable storage media include all types of storage media that store instructions that can be deciphered by a computer. Examples include read-only memory (ROM), random access memory (RAM), magnetic tape, magnetic disks, flash memory, and optical data storage devices.

[0199] Additionally, a computer-readable recording medium may be provided in the form of a non-transitory storage medium. Here, the term "non-transitory storage medium" simply means a tangible device that does not contain signals (e.g., electromagnetic waves). This term does not distinguish between cases where data is permanently stored in the storage medium and cases where data is temporarily stored. For example, a "non-transitory storage medium" may include a buffer in which data is temporarily stored.

[0200] According to one embodiment, the method according to various embodiments disclosed in the present document may be provided as included in a computer program product. The computer program product may be traded as a product between a seller and a buyer. The computer program product may be distributed in the form of a machine-readable recording medium (e.g., compact disc read only memory (CD-ROM)), or may be distributed online (e.g., downloaded or uploaded) via an application store (e.g., Play Store™) or directly between two user devices (e.g., smartphones). In the case of online distribution, at least a portion of the computer program product (e.g., a downloadable app) may be temporarily stored or temporarily generated on a machine-readable recording medium, such as the memory of a manufacturer's server, an application store's server, or an intermediary server.

[0201] The disclosed embodiments have been described with reference to the attached drawings as described above. Those skilled in the art will understand that the present invention can be implemented in forms other than the disclosed embodiments without altering the technical spirit or essential features of the present invention. The disclosed embodiments are illustrative and should not be construed as limiting.

Claims

1. Power supply unit that supplies direct current power; In a plurality of switching elements that convert the direct current power supplied from the power supply unit into three-phase alternating current power, a plurality of switching elements including upper switching elements and lower switching elements; A resistor element connected between the lower node of the lower switching elements and the power supply; and In the first mode, a control unit is included that generates a voltage command vector based on the average phase current determined while operating in the second mode; In the second mode, the control unit, A motor drive device that controls the plurality of switching elements so that none of the plurality of switching elements are turned on or off at a central point of the switching cycle, and determines the average phase current by sampling the current flowing through the resistance element at the central point of the switching cycle.

2. In paragraph 1, The above upper switching elements include a first upper switching element, a second upper switching element, and a third upper switching element, In the second mode, the control unit, A motor driving device that controls the plurality of switching elements so that the first upper switching element is turned off at the center point of the switching cycle and the second upper switching element and the third upper switching element are turned on.

3. In paragraph 2, In the second mode, the control unit, A motor driving device that controls the plurality of switching elements so that the first upper switching element is turned on at the starting point of the switching period and the ending point of the switching period, and the second upper switching element and the second upper switching element are turned off at the starting point of the switching period and the ending point of the switching period.

4. In paragraph 3, In the second mode, the control unit, A motor drive device that samples the current flowing through the resistive element at the central point of the switching cycle to determine the first average phase current corresponding to the first upper switching element.

5. In paragraph 4, In the second mode, the control unit, A motor driving device that samples the current flowing through the resistive element at the center point of the next switching cycle of the above switching cycle to determine a third average phase current corresponding to the third upper switching element, and determines the average phase current based on the first average phase current and the third average phase current.

6. In paragraph 1, The above upper switching elements include a first upper switching element, a second upper switching element, and a third upper switching element, In the above first mode, the control unit, A motor driving device that controls the plurality of switching elements so that the first upper switching element, the second upper switching element, and the third upper switching element are turned on at the central point of the switching cycle.

7. In paragraph 6, In the above first mode, the control unit, A motor driving device that controls the plurality of switching elements so that the first upper switching element, the second upper switching element, and the third upper switching element are turned off at the start point of the switching cycle and the end point of the switching cycle.

8. In paragraph 7, In the above first mode, the control unit, A motor driving device that controls the plurality of switching elements so that the first period is longer than the preset time based on the fact that the first upper switching element is on and the second upper switching element and the third upper switching element are off in the switching cycle is shorter than the preset time.

9. In paragraph 7, In the above first mode, the control unit, A motor driving device that controls the plurality of switching elements so that the second period is longer than the preset time based on the fact that the second period in which the first upper switching element and the second upper switching element are on and the third upper switching element is off in the switching cycle is shorter than the preset time.

10. In paragraph 1, The above control unit, In response to operating in the first mode for a first predetermined period of time, it operates in the second mode, and in response to operating in the second mode for a second predetermined period of time, it operates in the first mode. A motor driving device wherein the first predetermined time is longer than the second predetermined time.

11. A method for controlling a motor driving device, comprising a power supply unit that supplies direct current power, a plurality of switching elements that convert the direct current power supplied from the power supply unit into three-phase alternating current power, a plurality of switching elements including upper switching elements and lower switching elements, and a resistance element connected between the lower node of the lower switching elements and the power supply unit, In the first mode, a voltage command vector is generated based on the average phase current; In the second mode, the plurality of switching elements are controlled so that neither all of the plurality of switching elements are turned on nor all of the plurality of switching elements are turned off at the central point of the switching cycle; A control method of a motor drive device, comprising: in the second mode, determining the average phase current by sampling the current flowing through the resistance element at the center point of the switching cycle; 12. In paragraph 11, The above upper switching elements include a first upper switching element, a second upper switching element, and a third upper switching element, Controlling the plurality of switching elements in the second mode is as follows: A control method of a motor driving device, comprising: controlling the plurality of switching elements so that the first upper switching element is turned off at a central point of the switching cycle, and the second upper switching element and the third upper switching element are turned on.

13. In paragraph 12, Controlling the plurality of switching elements in the second mode is as follows: A control method for a motor driving device, comprising: controlling the plurality of switching elements so that the first upper switching element is turned on at a starting point of the switching period and an ending point of the switching period, and the second upper switching element and the second upper switching element are turned off at a starting point of the switching period and an ending point of the switching period.

14. In paragraph 13, In the second mode, the average phase current is determined by sampling the current flowing through the resistive element at the center point of the switching cycle. A control method of a motor driving device, comprising: sampling a current flowing through the resistive element at a central point of the switching cycle to determine a first average phase current corresponding to the first upper switching element.

15. In paragraph 14, A control method of a motor driving device further comprising: in the second mode, sampling a current flowing through the resistance element at a central point of a next switching cycle of the switching cycle to determine a third average phase current corresponding to the third upper switching element, and determining the average phase current based on the first average phase current and the third average phase current.

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