Motor driving device and home appliance having same

Abstract

A motor driving device and a home appliance according to one embodiment disclosed herein comprises: a converter for converting input alternating current power into direct current power to output the direct current power; a direct current terminal capacitor for storing the direct current power; an inverter which includes a plurality of upper arm switching elements and lower arm switching elements connected in series, and converts the direct current power from the direct current terminal capacitor into alternating current power to drive a motor; a current detection unit disposed between the direct current terminal capacitor and the inverter; gate drivers for driving the switching elements included in the inverter; bootstrap capacitors which are charged in response to the lower arm switching elements being turned on and supply a driving voltage to the gate drivers of the upper arm switching elements; and a control unit for controlling the inverter on the basis of the current detected by the current detection unit, wherein the control unit first turns some of the plurality of lower arm switching elements on and off and then turns the other lower arm switching elements on and off before driving the motor.

Description

Motor-driven devices and home appliances having the same

[0001] The present disclosure relates to a motor driving device and a home appliance having the same, and more particularly, to a motor driving device capable of easily identifying whether a motor and an inverter are faulty and the location of the fault, and a home appliance having the same.

[0002] Home appliances are devices used for the convenience of the user. Furthermore, home appliances such as air conditioners, washing machines, and refrigerators, used in designated spaces like homes and offices, each perform unique functions and operations based on user input.

[0003] Meanwhile, a motor drive device is a device for driving a motor having a rotor that rotates and a stator with coils wound around it. In particular, the motor drive device can be used to drive a motor within a home appliance.

[0004] Meanwhile, the motor drive device requires an inverter that outputs AC power to drive the motor.

[0005] The inverter can output AC power of various frequencies and can operate in particular in response to motor loads.

[0006] Meanwhile, the motor drive device includes a switching element. To drive the switching element, power must be supplied to the gate driver before driving. The bootstrap technique is widely used as a power supply method for the gate driver.

[0007] Meanwhile, during inverter operation, there is a possibility that any of the inverter's multiple switching elements may short-circuit or open. Furthermore, failures may occur in the motor, including the windings, magnets, and bearings.

[0008] Previously, there were individual compressor protection and motor protection technologies, but they required a large number of information / sensors and it was difficult to accurately diagnose the fault location.

[0009] When a motor-driven compressor or fan stops, it's necessary to accurately diagnose the cause of the failure and replace the faulty component. However, when a failure occurs in the inverter's drive circuit (semiconductor components and drive IC) or in the motor (windings, magnets, bearings, etc.), the symptoms—overcurrent, overvoltage, and stoppage—are similar, making it difficult to pinpoint the faulty component.

[0010] For example, it is difficult to distinguish between a motor short circuit and an inverter IGBT switch open, or between a motor short circuit, a motor ground fault, and an inverter IGBT switch short circuit.

[0011] Prior art document 1 (Japanese JP 3108964 B2) is a technology for detecting leakage current and ground faults, phase loss and phase-to-phase short circuits of a motor, but cannot detect abnormalities in the drive section of an inverter, and abnormalities in the drive section of the inverter may be misdiagnosed as motor failure.

[0012] Prior document 2 (European EP 4170886 A1) could not distinguish whether a short circuit occurred in the inverter or the motor, and could not distinguish it from a ground fault.

[0013]

[0014] The purpose of the present disclosure is to provide a motor driving device capable of identifying whether a motor or inverter is faulty, and the type and location of the fault, and a home appliance having the same.

[0015] The purpose of the present disclosure is to provide a motor driving device capable of effectively performing fault diagnosis using a bootstrap circuit without adding a separate sensor, and a home appliance having the same.

[0016] The purpose of the present disclosure is to provide a motor driving device capable of accurately identifying the type and location of a fault in a motor and inverter, thereby reducing the time and cost required for fault diagnosis, and a home appliance equipped with the same.

[0017] The purpose of the present disclosure is to provide a motor driving device capable of accurately identifying the type and location of a failure of a motor and an inverter to prevent increased costs due to simultaneous replacement, and a home appliance equipped with the same.

[0018] The tasks of the present disclosure are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the description below.

[0019] In order to achieve the above or other purposes, a motor driving device according to one aspect of the present disclosure and a home appliance having the same can accurately determine whether there is a fault and the location of the fault by using sensing data acquired while charging a bootstrap capacitor.

[0020] In order to achieve the above or other purposes, a motor driving device according to one aspect of the present disclosure and a home appliance having the same can accurately determine whether there is a fault and the location of the fault while charging a bootstrap capacitor before driving the motor.

[0021] In order to achieve the above or other purposes, a motor driving device according to one aspect of the present disclosure and a home appliance having the same can obtain highly discriminatory data by turning on the lower arm switch twice or more in a bootstrap charging sequence.

[0022] A motor driving device and a home appliance according to one embodiment of the present disclosure include a converter that converts input AC power into DC power and outputs it, a DC capacitor that stores the DC power, an inverter that converts the DC power from the DC capacitor into AC power and drives a motor, a current detection unit that is arranged between the DC capacitor and the inverter, gate drivers that drive the switching elements included in the inverter, and bootstrap capacitors that are charged according to the turn-on of the lower arm switching element and supply a driving voltage to the gate driver of the upper arm switching element, and a control unit that controls the inverter based on a current detected by the current detection unit.

[0023] Before driving the above motor, the control unit first turns on and turns off some of the plurality of lower arm switching elements, and then turns on and turns off other lower arm switching elements.

[0024] The above control unit sequentially turns on and off the plurality of lower arm switching elements one by one.

[0025] Alternatively, the control unit first turns on and turns off one of the plurality of lower arm switching elements, and then turns on and turns off the remaining lower arm switching elements.

[0026] Before driving the motor, the control unit sequentially charges the bootstrap capacitors, and diagnoses whether the inverter and the motor are faulty based on the current detected by the current detection unit during the period in which each bootstrap capacitor is charged.

[0027] A motor drive device and a home appliance according to one embodiment of the present disclosure further include a DC voltage source for supplying power to the bootstrap capacitors, and bootstrap resistors for forming a path for current flowing from the DC voltage source to the bootstrap capacitors.

[0028] A motor drive device and a home appliance according to one embodiment of the present disclosure further include bootstrap diodes connected in series with the bootstrap resistors.

[0029] The time for turning on each lower arm switching element is 0.1 to 2.3 times the time constant value of the bootstrap capacitor and bootstrap resistor connected to each lower arm switching element.

[0030] The control unit diagnoses whether the inverter and the motor are faulty based on the current detected by the current detection unit.

[0031] The control unit diagnoses whether the inverter and the motor are faulty based on the sampled current value from the current detected by the current detection unit during the section in which the lower arm switching element is turned on.

[0032] The control unit diagnoses whether the inverter and the motor are faulty based on any one of the average value, maximum value, sum value, difference value, and sum value of the differences of the sampled current values ​​detected by the current detection unit in the section where the lower arm switching element is turned on.

[0033] The above control unit determines that the motor has a short-circuit failure if the current detected by the current detection unit in the section where the first lower arm switching element is turned on is greater than the current detected by the current detection unit in the section where the second lower arm switching element is turned on.

[0034] The above control unit determines that the motor has a short-circuit failure if, during normal operation, the current detected by the current detection unit in the section where the second lower arm switching element is turned on is greater than the current detected by the current detection unit in the section where the second lower arm switching element is turned on.

[0035] The above control unit determines that a phase open fault corresponding to the third lower arm switching element of the motor occurs when the current detected by the current detection unit in the section where the third lower arm switching element is turned on is greater than the current detected by the current detection unit in the section where the third lower arm switching element is turned on during normal operation.

[0036] The above control unit determines that, if no current is detected by the current detection unit only in the section where the lower arm switching element is turned on, there is an open fault in the corresponding lower arm switching element or the gate driver connected to the corresponding lower arm switching element.

[0037] The control unit determines that, if no current is detected by the current detection unit in a plurality of turn-on sections, a short-circuit failure of at least one lower switching element or at least one gate driver occurs.

[0038] The above control unit determines that, in the section where the lower arm switching element is turned on, if a change occurs in the sum of the differences between the sampled current values ​​detected by the current detection unit during normal operation, there is a short circuit failure of the motor.

[0039] The above control unit determines that there is a short circuit fault in the cable connecting the inverter and the motor when the currents detected by the current detection unit are the same in the section where each lower arm switching element is turned on.

[0040]

[0041] According to at least one of the embodiments of the present disclosure, it is possible to easily determine whether a motor or inverter is faulty, and the type and location of the fault.

[0042] Additionally, according to at least one of the embodiments of the present disclosure, fault diagnosis can be effectively performed using a bootstrap circuit without adding a separate sensor.

[0043] Additionally, according to at least one of the embodiments of the present disclosure, a motor can be stably driven using an accurately estimated motor constant.

[0044] In addition, according to at least one of the embodiments of the present disclosure, it is possible to accurately identify the type and location of a fault in a motor and an inverter, thereby reducing the time and cost required for fault diagnosis.

[0045] Additionally, according to at least one of the embodiments of the present disclosure, it is possible to accurately identify the type and location of a failure of a motor and an inverter, thereby preventing increased costs due to simultaneous replacement.

[0046] Meanwhile, various other effects will be disclosed directly or implicitly in the detailed description according to the embodiments of the present disclosure to be described later.

[0047] FIG. 1 is a drawing illustrating the configuration of an air conditioner according to one embodiment of the present disclosure.

[0048] Figure 2 is a schematic diagram of the outdoor unit and indoor unit of Figure 1.

[0049] Figure 3 is a circuit diagram of a motor driving device according to one embodiment of the present disclosure.

[0050] Figure 4 is a circuit diagram of a motor driving device according to one embodiment of the present disclosure.

[0051] FIG. 5 is a drawing for reference in a description of fault diagnosis according to an embodiment of the present disclosure.

[0052] FIG. 6 and FIG. 7 are simplified drawings of a bootstrap circuit according to one embodiment of the present disclosure.

[0053] Figure 8 is a drawing referenced in the description of bootstrap coffee seater charging.

[0054] FIG. 9 is a drawing for reference in a description of bootstrap capacitor charging according to one embodiment of the present disclosure.

[0055] FIG. 10 is a diagram illustrating the pulse width of an inverter lower arm switch according to one embodiment of the present disclosure.

[0056] FIG. 11 is a diagram illustrating switching pulses and current measurement values ​​for charging a bootstrap capacitor according to one embodiment of the present disclosure.

[0057] Figure 12 is a diagram illustrating a motor phase short circuit failure.

[0058] FIG. 13 is a diagram illustrating current sensing values ​​during normal operation according to one embodiment of the present disclosure.

[0059] Figure 14 is a diagram illustrating a switching pulse for charging a bootstrap capacitor and voltage / current values ​​in the event of a motor phase short-circuit fault.

[0060] Figure 15 is a diagram illustrating an open circuit fault in a motor.

[0061] Figure 16 is a diagram illustrating a switching pulse for charging a bootstrap capacitor and voltage / current values ​​in the event of a motor phase open fault.

[0062] Figure 17 is a diagram illustrating an inverter switching element open failure.

[0063] Figure 18 is a diagram illustrating a switching pulse and current value for charging a bootstrap capacitor when an inverter switching element open fault occurs.

[0064] Figure 19 is a diagram illustrating an inverter switching element short-circuit failure.

[0065] Figure 20 is a diagram illustrating a switching pulse and current value for charging a bootstrap capacitor when an inverter switching element short-circuits.

[0066] Figures 21 to 23 are drawings for reference in the description of interlayer short circuit faults and fault diagnosis of the motor.

[0067] Figures 24 and 25 are drawings for reference in the description of cable disconnection fault and fault diagnosis.

[0068] Figures 26 and 27 are drawings referenced in the description of ground fault and fault diagnosis.

[0069]

[0070] Hereinafter, embodiments disclosed in this specification will be described in detail with reference to the attached drawings. Regardless of the drawing numbers, identical or similar components are assigned the same reference numbers, and redundant descriptions thereof will be omitted.

[0071] The suffixes “module” and “part” used for components in the following description are given or used interchangeably only for the convenience of writing specifications, and do not have distinct meanings or roles in themselves.

[0072] Terms that include ordinal numbers, such as first, second, etc., may be used to describe various components, but the components are not limited by these terms. These terms are used solely to distinguish one component from another.

[0073] Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0074] Meanwhile, the motor drive device described in this specification may be a motor drive device installed in a home appliance. Home appliances include refrigerators, washing machines, dryers, air conditioners, dehumidifiers, cooking appliances, vacuum cleaners, and the like. Below, among various home appliances, air conditioners will be described with a focus on them.

[0075] FIG. 1 is a drawing illustrating the configuration of an air conditioner according to one embodiment of the present disclosure.

[0076] Referring to FIG. 1, an air conditioner (100) according to the present invention may include an indoor unit (21) and an outdoor unit (31) connected to the indoor unit (21).

[0077] The indoor unit (21) of the air conditioner can be any of a stand-alone air conditioner, a wall-mounted air conditioner, and a ceiling-mounted air conditioner, but the drawing exemplifies a stand-alone indoor unit (21).

[0078] Meanwhile, the air conditioner (100) may further include at least one of a ventilation device, an air purifier, a humidifier, and a heater, and may operate in conjunction with the operations of the indoor unit and the outdoor unit.

[0079] The outdoor unit (31) includes a compressor (not shown) that receives and compresses refrigerant, an outdoor heat exchanger (not shown) that exchanges heat between the refrigerant and outdoor air, an accumulator (not shown) that extracts gaseous refrigerant from the supplied refrigerant and supplies it to the compressor, and a four-way valve (not shown) that selects the flow path of the refrigerant according to heating operation. In addition, it further includes a number of sensors, valves, and an oil recovery device, but a description of their configuration will be omitted below.

[0080] The outdoor unit (31) operates the provided compressor and outdoor heat exchanger to compress or heat-exchange the refrigerant according to the settings and supply the refrigerant to the indoor unit (21). The outdoor unit (31) can be driven by a remote controller (not shown) or a demand of the indoor unit (21). At this time, since the cooling / heating capacity is varied in response to the indoor unit being driven, the number of outdoor units in operation and the number of compressors installed in the outdoor unit can also be varied. In addition, although one indoor unit (21) and one outdoor unit (31) are illustrated in FIG. 1, the present disclosure is not limited thereto. For example, multiple indoor units (21) can be connected to one outdoor unit (31) via refrigerant piping.

[0081] At this time, the outdoor unit (31) supplies compressed refrigerant to the connected indoor unit (21).

[0082] The indoor unit (21) receives refrigerant from the outdoor unit (31) and discharges hot and cold air into the room. The indoor unit (21) includes an indoor heat exchanger (not shown), an indoor fan (not shown), an expansion valve (not shown) for expanding the supplied refrigerant, and a number of sensors (not shown).

[0083] At this time, the outdoor unit (31) and the indoor unit (21) are connected by wire or wirelessly to transmit and receive data to each other, and the outdoor unit and the indoor unit are connected by wire or wirelessly to a remote controller (not shown) and can operate under the control of the remote controller (not shown).

[0084] A remote control (not shown) is connected to an indoor unit (21), and can input a user's control command to the indoor unit and receive and display status information of the indoor unit. At this time, the remote control can communicate with the indoor unit via wired or wireless communication depending on the connection type.

[0085] Figure 2 is a schematic diagram of the outdoor unit and indoor unit of Figure 1.

[0086] Referring to Fig. 2, the air conditioner (100) is largely divided into an indoor unit (21) and an outdoor unit (31).

[0087] The outdoor unit (31) may include a compressor (102) that compresses refrigerant, a compressor motor (102b) that drives the compressor, an outdoor heat exchanger (104) that dissipates heat from the compressed refrigerant, an outdoor fan (105a) that is arranged on one side of the outdoor heat exchanger (104) to promote heat dissipation from the refrigerant, and an outdoor blower (105) that is formed by a motor (105b) that rotates the outdoor fan (105a), an expansion mechanism or expansion valve (106) that expands condensed refrigerant, a cooling / heating switching valve or four-way valve (110) that changes the flow path of the compressed refrigerant, and an accumulator (103) that temporarily stores the vaporized refrigerant to remove moisture and foreign substances and then supplies the refrigerant at a constant pressure to the compressor.

[0088] The indoor unit (21) includes an indoor heat exchanger (108) that is placed indoors and performs a cooling / heating function, an indoor fan (109a) that is placed on one side of the indoor heat exchanger (108) and promotes heat dissipation of the refrigerant, and an indoor blower (109) that is composed of an electric motor (109b) that rotates the indoor fan (109a).

[0089] At least one indoor heat exchanger (108) can be installed. At least one of an inverter compressor and a constant-speed compressor can be used as the compressor (102).

[0090] Additionally, the air conditioner (100) may be configured as an air conditioner that cools the room, or may be configured as a heat pump that cools or heats the room.

[0091] Meanwhile, the outdoor fan (105a) in the outdoor unit (31) can be driven by an outdoor fan driving unit (not shown) that drives a motor (105b).

[0092] Meanwhile, the compressor (102) in the outdoor unit (31) can be driven by a compressor motor drive unit (not shown) that drives the compressor motor (102b).

[0093] Meanwhile, the indoor fan (109a) in the indoor unit (21) can be driven by an indoor fan driving unit (not shown) that drives an indoor fan motor (109b).

[0094] An outdoor fan drive unit may be referred to as an outdoor fan drive unit. An indoor fan drive unit may also be referred to as an indoor fan drive unit.

[0095] FIG. 3 is an example of a circuit diagram of a motor driving device according to one embodiment of the present disclosure.

[0096] Referring to FIG. 3, a motor driving device (400) according to one embodiment of the present disclosure may include a converter (410) that converts input power (201) into direct current power and outputs it to a dc terminal, a converter control unit (415), a capacitor (C) connected to the dc terminal, an inverter (420) having a plurality of switching elements and converting direct current power from the capacitor (C) into alternating current, and an inverter control unit (430) that controls the inverter (420).

[0097] The motor driving device (400) may further include an input voltage detection unit (A), a DC voltage detection unit (B), an input current detection unit (D), and an output current detection unit (E).

[0098] The converter (410) can convert commercial AC power (201) into DC power and output it. To this end, the converter (410) may be equipped with a rectifier. In addition, it is also possible to additionally include a reactor.

[0099] A smoothing capacitor (C) is connected to the output terminal of the converter (410). The capacitor (C) can store the power output from the converter (410). Since the power output from the converter (410) is DC power, it can be called a DC terminal capacitor.

[0100] The above inverter (420) can output the converted AC power to the motor (250).

[0101] Referring to FIG. 3, the input voltage detection unit (A) can detect the input voltage (Vs) from the input AC power source (201).

[0102] The input voltage detection unit (A) may include a resistance element, an OP AMP, etc. for voltage detection. The detected input voltage (Vs) may be applied to the inverter control unit (230) as a discrete signal in the form of a pulse.

[0103] Meanwhile, the zero crossing point of the input voltage can also be detected by the input voltage detection unit (A).

[0104] The input current detection unit (D) can detect the input current (is) input from a commercial AC power source (201). For this purpose, a CT (current transformer), a shunt resistor, etc. can be used as the input current detection unit (D). The detected input current (is) can be input to the inverter control unit (430) as a pulse-shaped discrete signal for power consumption calculation.

[0105] Next, a capacitor (C) may be provided at the output terminal of the converter (410) to store or smooth the power converted by the converter (410). At this time, both ends of the capacitor (C) may be referred to as a dc terminal. Therefore, the capacitor (C) may also be referred to as a dc terminal capacitor.

[0106] Meanwhile, the converter control unit (415) can generate a converter switching control signal (Scc) based on the input voltage (Vs), input current (Is), and dc terminal voltage (Vdc), and output it to the converter (410).

[0107] The DC voltage detection unit (B) can detect the DC voltage (Vdc) at both ends of the smoothing capacitor (C). To this end, the DC voltage detection unit (B) can include a resistance element, an amplifier, etc. The detected DC voltage (Vdc) can be input to the inverter control unit (430) as a discrete signal in the form of a pulse.

[0108] The inverter (420) can drive the motor (250). To this end, the inverter (420) has a plurality of inverter switching elements, and can convert smoothed direct current (Vdc) into three-phase alternating current (AC) of a predetermined frequency by the on / off operation of the switching elements, and output the same to the three-phase synchronous motor (250).

[0109] The inverter (420) comprises a plurality of upper and lower arm switching elements connected in series. The inverter (420) comprises a pair of upper and lower arm switching elements, each of which is connected in series, and a total of three pairs of upper and lower arm switching elements are connected in parallel. A diode is connected in antiparallel to each switching element.

[0110] The switching elements within the inverter (420) perform on / off operations of each switching element based on the inverter switching control signal (Sic) from the inverter control unit (430). As a result, a three-phase AC power source having a predetermined frequency is output to the three-phase synchronous motor (250).

[0111] The inverter control unit (430) can control the switching operation of the inverter (420). To this end, the inverter control unit (430) detects the output current (i) detected by the output current detection unit (E). o ) can be entered.

[0112] The inverter control unit (430) outputs an inverter switching control signal (Sic) to the inverter (420) to control the switching operation of the inverter (420). The inverter switching control signal (Sic) is a switching control signal of pulse width modulation (PWM) and is an output current value (i) detected from the output current detection unit (E). o ) is generated and output based on it.

[0113] The output current detection unit (E) detects the output current (i) flowing between the inverter (420) and the three-phase motor (250). o ) is detected. That is, the current flowing in the motor (250) is detected. The output current detection unit (E) can detect all output currents (ia, ib, ic) of each phase, or can detect the output currents of two phases using three-phase balance.

[0114] The output current detection unit (E) may be located between the inverter (420) and the motor (250), and a CT (current transformer), shunt resistor, etc. may be used to detect the current.

[0115] When shunt resistors are used, three shunt resistors may be positioned between the inverter (420) and the synchronous motor (250), or one end of each shunt resistor may be connected to the three lower arm switching elements of the inverter (420). Alternatively, two shunt resistors may be used using three-phase equilibrium. Alternatively, when one shunt resistor is used, the shunt resistor may be positioned between the aforementioned capacitor (C) and the inverter (420).

[0116] Detected output current (i o ) is a discrete signal in the form of a pulse, which can be applied to the inverter control unit (430), and the detected output current (i o ) is generated based on the inverter switching control signal (Sic).

[0117] Meanwhile, the motor (250) may be a three-phase motor. The motor (250) has a stator and a rotor, and an AC power of a predetermined frequency is applied to the coils of the stator of each phase (a, b, c phases), causing the rotor to rotate. The stator is composed of a plurality of turns of windings.

[0118] The type of motor (250) may include various forms such as a brushless direct current motor (BLDC motor), a synchronous motor, and an induction motor. For example, the motor (250) may include a surface-mounted permanent magnet synchronous motor (SMPMSM), an interior permanent magnet synchronous motor (IPMSM), and a synchronous reluctance motor (Synrm). Among these, SMPMSM and IPMSM are synchronous motors that apply permanent magnets (Permanent Magnet Synchronous Motors (PMSM), and Synrm is characterized by not having a permanent magnet.

[0119] FIG. 4 is a circuit diagram of a motor driving device according to an embodiment of the present disclosure, illustrating a circuit diagram of a motor driving device including a bootstrap circuit.

[0120] Referring to FIG. 4, the motor driving device includes an inverter (420) including a plurality of switching elements (Sa, Sx, Sb, Sy, Sc, Sz).

[0121] The inverter (420) may include a first phase (A-phase) leg including a first upper-arm switching element (Sa) and a first lower-arm switching element (Sx) arranged in series, a second phase (B-phase) leg including a second upper-arm switching element (Sb) and a second lower-arm switching element (Sy) arranged in series, and a third phase (C-phase) leg including a third upper-arm switching element (Sc) and a third lower-arm switching element (Sz) arranged in series.

[0122] Additionally, the motor driving device may include a gate driving circuit (500) including gate drivers (gate drivers, 511) that drive a plurality of switching elements (Sa, Sx, Sb, Sy, Sc, Sz) included in the inverter (420) and bootstrap capacitors (Cboot).

[0123] The gate drive circuit (500) may include a DC voltage source (520) that supplies power to bootstrap capacitors (Cboot) and a switching unit (510) for switching.

[0124] A DC voltage source (520) may be used in common, and a switching unit (510) may be connected to the legs of each phase. Alternatively, the DC voltage source (520) may also be connected to the legs of each phase.

[0125] In Fig. 5, only the internal configuration of the switching unit (510) connected to the upper-arm switching element (Sa) of phase a is illustrated as an example.

[0126] The bootstrap capacitors (Cboot) are charged according to the turn-on of the lower arm switching elements (Sx, Sy, Sz) and supply a driving voltage to the gate driver (511) of the upper arm switching elements (Sa, Sb, Sc).

[0127] As switching elements (Sa, Sx, Sb, Sy, Sc, Sz), metal oxide semiconductor field effect transistors (MOSFETs), insulated gate bipolar mode transistors (IGBTs), etc. can be used.

[0128] The inverter (420) is composed of four or more switching elements (MOSFET, IGBT, GaN, SiC, etc.), and each switching element may have a driving circuit (bootstrap circuit). The switching element can operate stably through charging / discharging of a capacitor (Cboot) within the driving circuit (bootstrap circuit).

[0129] The gate drive circuit (500) may further include a DC voltage source (520) that supplies power to the bootstrap capacitors (Cboot), and bootstrap resistors (Rboot) that form a path for current flowing from the DC voltage source (520) to the bootstrap capacitors (Cboot).

[0130] Additionally, bootstrap diodes (Dboot) can be connected in series with bootstrap resistors (Rboot).

[0131] The bootstrap capacitors (Cboot), bootstrap resistors (Rboot), and bootstrap diodes (Dboot) can be referred to as a bootstrap circuit. In a broader sense, the entire gate drive circuit (500) can also be referred to as a bootstrap circuit.

[0132] Bootstrap resistors (Rboot) can form a current path according to the voltage difference between the DC voltage source (520) and the bootstrap capacitor (Cboot) and can limit the size of the current. Bootstrap diodes (Dboot) can limit the current path so that the bootstrap current flows from the DC voltage source (520) toward the bootstrap capacitor (Cboot).

[0133] The control unit (430) can charge the bootstrap capacitor (Cboot) by controlling the switching operation of the upper and lower arm switching elements (Sa, Sx, Sb, Sy, Sc, Sz).

[0134] More specifically, the control unit (430) can provide a switching signal for PWM control to the gate driver (511), and the gate driver (511) can turn on the switching elements (Sa, Sx, Sb, Sy, Sc, Sz) by applying a gate driving voltage to them according to the switching signal.

[0135] The control unit (430) may be the inverter control unit (430) described above, or may be a higher-level controller that controls the inverter control unit (430). Alternatively, the control unit (430) may include an inverter control unit (430) that controls the inverter and a diagnostic unit that performs fault diagnosis. Hereinafter, an example in which the control unit (430) performs control and fault diagnosis of the inverter (420) will be described.

[0136] Meanwhile, the lower switching elements (Sx, Sy, Sz) can be switched by supplying current from a single DC voltage source (520). The lower switching elements (Sx, Sy, Sz) can be connected to a common ground terminal.

[0137] Meanwhile, the Sangam switching elements (Sa, Sb, Sc) can charge the gate drive voltage to the bootstrap capacitors (Cboot) using the bootstrap method.

[0138] A current flows through the bootstrap capacitors (Cboot), the bootstrap resistor (Rboot), the bootstrap diode (Dboot), and the ground terminal (GND), thereby charging the gate drive voltage to the bootstrap capacitors (Cboot).

[0139] For example, when the upper arm switching element (Sa) among a pair of serially connected leg switching elements (Sa, Sx) is turned off and the lower arm switching element (Sx) is turned on, a current flowing through the bootstrap capacitor (Cboot1), the lower arm switching element (Sx), the resistor element (Rbs), and the ground terminal (GND) is formed, thereby charging the gate driving voltage in the bootstrap capacitor (Coot1). That is, the gate driving voltage is charged in the bootstrap capacitor (Coot1) by the bootstrap method.

[0140] Meanwhile, the method of charging the bootstrap capacitor (Cboot) of the gate driving circuit (500) corresponding to the Sangam switching element (Sa, Sb, Sc) can be controlled by the control unit (430).

[0141] That is, the control unit (430) can control the upper arm switching elements (Sa, Sb, Sc) and the lower arm switching elements (Sx, Sy, Sz) in the inverter (420) to turn on the lower arm switching elements (Sx, Sy, Sz) before the operation of a specific phase leg, so that the gate driving voltage is charged in the bootstrap capacitors (Cboot) connected to the gate driver (511) corresponding to the upper arm switching elements (Sa, Sb, Sc).

[0142] The current detection unit (425) may be placed between the dc capacitor (C) and the inverter (420). The current detection unit (425) may be the output current detection unit (E) described above. The current detection unit (425) may be mounted at the bottom of each leg. Alternatively, the current detection unit (425) may be mounted on the dc terminal (input terminal of the inverter (420)). Alternatively, the current detection unit (425) may be mounted on the output terminal (input terminal of the motor (250)) of the inverter (420).

[0143] The control unit (430) controls the inverter (420) based on the current detected by the current detection unit (425).

[0144] When a malfunction occurs, it's crucial to accurately diagnose the component failure and replace or repair the defective part. However, without knowing the exact cause of the failure and the defective part, service providers may mistakenly replace even working parts, failing to resolve the cause of the malfunction.

[0145] Although the causes of failures in the drive circuit are diverse, the phenomena caused by the failures are similar, so the accuracy of failure diagnosis may be reduced.

[0146] FIG. 5 is a drawing for reference in a description of fault diagnosis according to an embodiment of the present disclosure.

[0147] Referring to Fig. 5, a switching element short circuit of the inverter (420), a winding short circuit of the motor (250), and a ground fault may all result in a phenomenon in which the operation is quickly stopped by the overcurrent protection circuit (Arm short circuit) due to a sudden increase in current (HW overcurrent).

[0148] And the opening of the switching element of the inverter (420), the short circuit of the motor winding, and the locking of the motor may result in the phenomenon of the motor not rotating (locking). Or, it may result in a high overcurrent (SW overcurrent) exceeding a certain level. [

[0149] Figure 5 shows the causes of failures in the driving circuit and the phenomena that may occur.

[0150] In addition, the control unit (430) can accurately diagnose inverter failures (switch open, short circuit, Drive IC abnormality, etc.) and motor failures (line-to-line short circuit, layer-to-layer short circuit, phase open circuit, winding ground fault, demagnetization, binding, etc.) by performing rule or learning-based diagnostic logic.

[0151] Learning-based diagnostic logic can be utilized even in areas where model establishment is difficult, and has advantages in terms of temporal context judgment.

[0152] For example, the control unit (430) includes an artificial neural network that is machine-learned based on voltage, current, etc., and can determine whether there is a failure and identify major failed components.

[0153] The control unit (430) can provide the fault diagnosis results to the user or worker's terminal through a communication unit (not shown), or control the display (not shown) to display the fault diagnosis results.

[0154] The control unit (430) can diagnose whether the inverter (420) and the motor (250) are faulty based on the current detected by the current detection unit (425).

[0155] In particular, the control unit (430) can accurately determine whether there is a fault and the location of the fault by using sensing data obtained from the current detection unit (425) while charging the bootstrap capacitor (Cboot).

[0156] Before driving the motor, the control unit (430) can accurately determine whether there is a fault and the location of the fault while charging the bootstrap capacitor (Cboot).

[0157] The control unit (430) can obtain highly discriminative data by turning on the lower arm switch twice or more in a bootstrap charging sequence.

[0158] Depending on the location of a fault, such as a short circuit or open circuit of a specific component, the impedance and the impedance change tendency vary. Accordingly, the pattern of voltage and current data detected during the bootstrap charging sequence that charges the bootstrap capacitor (Cboot) also varies. That is, the impedance varies depending on the location of the fault, and a short circuit / open circuit fault of the motor can be determined by the waveform changes of the injection signal and the response signal. The injection signal may be a pulse that turns on the lower arm switching elements (Sx, Sy, Sz) during the bootstrap charging sequence. The response signal may be a current detected by the current detection unit (425) during the bootstrap charging sequence.

[0159] The control unit (430) can determine whether there is a fault based on the current detected by the current detection unit (425) during the bootstrap charging sequence that charges the bootstrap capacitor (Cboot), and can determine the type of fault and the location of the fault.

[0160] FIG. 6 and FIG. 7 are simplified drawings of a bootstrap circuit according to an embodiment of the present disclosure, and illustrate the equivalent circuit of a bootstrap circuit (530), an inverter (420), and a motor (250) in a simplified manner.

[0161] The control unit (430) detects various failures of the inverter (420) and the motor (250) by utilizing the inverter switching element driving circuit (bootstrap circuit (530)).

[0162] The gate drive circuit (500) may include a DC voltage source (520) that supplies power to bootstrap capacitors (Cboot) and a bootstrap circuit (530). The bootstrap circuit (530) may be connected to the lower arm switching elements (Sx, Sy, Sz) of the inverter (420).

[0163] The bootstrap circuit (530) may include bootstrap capacitors (Cboot) that are charged when a pulse is applied by switching the lower switching elements (Sx, Sy, Sz), and bootstrap resistors (Rboot) and bootstrap diodes (Dboot) that form a path for current flowing from a DC voltage source (520) to the bootstrap capacitors (Cboot).

[0164] The control unit (430) charges the bootstrap capacitors (Cboot) by turning on / off the lower arm switching elements (Sx, Sy, Sz) of the inverter (420).

[0165] While charging the bootstrap capacitors (Cboot), current flows to the input terminal (dc terminal) of the inverter (420), and the current can be measured by the current detection unit (425).

[0166] The current detection unit (425) may be one current detection means (Shunt, CT, etc.) mounted on the DC terminal, or three current detection means (Shunt, CT, etc.) mounted on each lower leg of the inverter (420), or a current detection means (Shunt, CT, etc.) mounted on the output terminal (motor input terminal) of the inverter (420).

[0167] The bootstrap circuit (530) may include a first bootstrap capacitor (Cboot1) that is charged in response to the turn-on of the first lower-arm switching element (Sx) and supplies a driving voltage to the gate driver (511) of the first upper-arm switching element (Sa), a second bootstrap capacitor (Cboot2) that is charged in response to the turn-on of the second lower-arm switching element (Sy) and supplies a driving voltage to the gate driver (511) of the second upper-arm switching element (Sb), and a third bootstrap capacitor (Cboot3) that is charged in response to the turn-on of the third lower-arm switching element (Sz) and supplies a driving voltage to the gate driver (511) of the third upper-arm switching element (Sc).

[0168] Additionally, a first bootstrap resistor (Rboot1) and a first bootstrap diode (Dboot1) may be connected to the first bootstrap capacitor (Cboot1). The first bootstrap circuit (531) may include a first bootstrap capacitor (Cboot1), a first bootstrap resistor (Rboot1), and a first bootstrap diode (Dboot1).

[0169] A second bootstrap resistor (Rboot2) and a second bootstrap diode (Dboot2) may be connected to the second bootstrap capacitor (Cboot2). The second bootstrap circuit (532) may include a second bootstrap capacitor (Cboot2), a second bootstrap resistor (Rboot2), and a second bootstrap diode (Dboot2).

[0170] A third bootstrap resistor (Rboot3) and a third bootstrap diode (Dboot3) may be connected to the third bootstrap capacitor (Cboot3). The third bootstrap circuit (533) may include a third bootstrap capacitor (Cboot3), a third bootstrap resistor (Rboot3), and a third bootstrap diode (Dboot3).

[0171] Figure 8 is a drawing referenced in the description of conventional bootstrap coffee seater charging.

[0172] Referring to Fig. 8, in a conventional general method, all lower arm switches (Sx, Sy, Sz) of an inverter (420) are turned on simultaneously to charge a capacitor (Cboot). When all lower arm switches (Sx, Sy, Sz) are turned on simultaneously, the voltages at the three-phase bootstrap capacitors (Cboot1, Cboot2, Cboot3) increase equally and converge to the bootstrap circuit power voltage. In addition, after the capacitor (Cboot) is fully charged, the lower arm switches (Sx, Sy, Sz) are turned off simultaneously.

[0173] In order to detect various failures of the inverter (420) and the motor (250), the motor driving device performs a diagnosis through the current sensed by the current detection unit (425) while charging the bootstrap capacitor (Cboot) through the on / off of the lower arm switches (Sx, Sy, Sz) of each leg of the inverter (420). To this end, the charging sequence of the bootstrap capacitor (Cboot) is configured for the purpose to detect various failures.

[0174] The control unit (430) first turns on some of the plurality of lower arm switching elements (Sx, Sy, Sz) before driving the motor (250), and then turns them off after a time corresponding to a set pulse width.

[0175] Thereafter, the control unit (430) turns on and turns off at least some of the other lower arm switching elements that are not turned on / off among the plurality of lower arm switching elements (Sx, Sy, Sz).

[0176] The control unit (430) performs the same charging sequence of the bootstrap capacitor (Cboot) until the bootstrap capacitor (Cboot) is charged.

[0177] In addition, the control unit (430) performs a fault diagnosis based on the current detected by the current detection unit (425) in a section in which one or more of the plurality of lower arm switching elements (Sx, Sy, Sz) are turned on.

[0178] That is, before driving the motor (250), the control unit (430) sequentially charges the bootstraps (Cboot), and in the section where each bootstrap (Cboot1, Cboot2, Cboot3) is charged, based on the current detected by the current detection unit (425), diagnoses whether the inverter (420) and the motor (250) are faulty.

[0179] The control unit (430) can diagnose whether the inverter (420) and the motor (250) are faulty based on the sampled current value from the current detected by the current detection unit (425) in the section where the lower switching element (Sx, Sy, Sz) is turned on.

[0180] In addition, the control unit (430) can diagnose whether the inverter (420) and the motor (250) are faulty based on any one of the average value, maximum value, sum value, difference value, and sum value of the differences of the current values ​​sampled by the current detection unit (425) in the section where the lower-arm switching elements (Sx, Sy, Sz) are turned on. A large difference value means a steeper slope, which means a large amount of change in the value. The difference value is used to most simply determine the amount of change in the value, and the slope and change amount values ​​can also be used in the same manner.

[0181] According to the present disclosure, a fault can be diagnosed by utilizing a processed value based on a current value, such as an average, an accumulation, a difference, or a difference of displacement, detected by a current detection unit (425) according to a processed charging sequence of bootstraps (Cboot). Accordingly, an open and a short of a semiconductor element (or Drive IC) of an inverter (420), and a ground fault, a winding short, a line short, a phase open, an inter-turn short, a cable disconnection (disconnection) of a motor (250), etc. can be diagnosed, and it is possible to more accurately determine which component among the inverter (420) PCB and (250) is faulty.

[0182] FIG. 9 is a diagram for reference in a description of bootstrap capacitor charging and fault diagnosis according to one embodiment of the present disclosure.

[0183] Referring to FIG. 9, unlike the conventional method of FIG. 8, the lower arm switching elements (Sx, Sy, Sz) of the inverter (430) are not turned on / off simultaneously, but the operating timing of each lower arm switching element (Sx, Sy, Sz) is changed to charge the voltage of the bootstrap capacitors (Cboot) unevenly.

[0184] That is, it can be confirmed that the operating timings of the lower arm switching elements (Sx, Sy, Sz) of each leg of the inverter (430) are not the same, and the voltages of the bootstrap capacitors (Cboot) are also charged at different times, resulting in unbalanced charging.

[0185] Referring to FIG. 9, the control unit (430) can configure a charging sequence to sequentially turn on and off a plurality of lower arm switching elements (Sx, Sy, Sz) one by one.

[0186] In Fig. 9, an example of turning on / off in the order of the first phase (A phase), the second phase (B phase), and the third phase (C phase) is shown.

[0187] Referring to Fig. 9, the control unit (430) first applies a pulse to the first lower arm switching element (Sx). That is, the control unit (430) turns on / off the first lower arm switching element (Sx) among the plurality of lower arm switching elements (Sx, Sy, Sz).

[0188] Accordingly, a current flowing through the DC voltage source (520), the first bootstrap capacitor (Cboot1), the first bootstrap resistor (Rboot1), the first bootstrap diode (Dboot1), and the ground terminal (GND) is formed, thereby allowing the voltage to be charged to the first bootstrap capacitor (Cboot1).

[0189] Meanwhile, the second bootstrap capacitor (Cboot2) and the third bootstrap capacitor (Cboot3) do not form a path toward the lower switching element (Sy, Sz), but a path is formed from the DC voltage source (520) to the motor (250), so that a small amount of voltage can be charged.

[0190] In the section where a pulse is applied to the first lower arm switching element (Sx), the voltage of the first bootstrap capacitor (Cboot1) increases relatively significantly, and the voltage of the second bootstrap capacitor (Cboot2) and the third bootstrap capacitor (Cboot3) increases relatively small.

[0191] Thereafter, the control unit (430) applies a pulse to the second lower arm switching element (Sy). That is, the control unit (430) turns on / off the second lower arm switching element (Sy) among the plurality of lower arm switching elements (Sx, Sy, Sz).

[0192] Accordingly, a current flowing through the DC voltage source (520), the second bootstrap capacitor (Cboot2), the second bootstrap resistor (Rboot2), the first bootstrap diode (Dboot2), and the ground terminal (GND) is formed, thereby allowing the second bootstrap capacitor (Cboot2) to be charged with voltage.

[0193] Meanwhile, the first bootstrap capacitor (Cboot1) and the third bootstrap capacitor (Cboot3) can also be charged with a small amount of voltage.

[0194] In the section where a pulse is applied to the second lower switching element (Sy), the voltage of the second bootstrap capacitor (Cboot2) increases relatively significantly, and the voltage of the first bootstrap capacitor (Cboot1) and the third bootstrap capacitor (Cboot3) increases relatively small.

[0195] In addition, since the voltage charged from the first pulse also acts from the second pulse, the current value decreases. Referring to Fig. 9, it can be confirmed that the current sensing value in the section where the pulse is applied to the second lower arm switching element (Sy) is lower than the current sensing value in the section where the pulse is applied to the first lower arm switching element (Sx).

[0196] Thereafter, the control unit (430) applies a pulse to the third lower arm switching element (Sz). That is, the control unit (430) turns on / off the third lower arm switching element (Sz) among the plurality of lower arm switching elements (Sx, Sy, Sz).

[0197] Accordingly, a current flowing through the DC voltage source (520), the third bootstrap capacitor (Cboot3), the third bootstrap resistor (Rboot3), the third bootstrap diode (Dboot3), and the ground terminal (GND) is formed, thereby allowing the voltage to be charged in the third bootstrap capacitor (Cboot3).

[0198] Meanwhile, the first bootstrap capacitor (Cboot1) and the second bootstrap capacitor (Cboot2) can also be charged with a small amount of voltage.

[0199] The current sensing value in the section where a pulse is applied to the third lower arm switching element (Sz) becomes smaller than the current sensing value in the section where a pulse is applied to the second lower arm switching element (Sy).

[0200] In Fig. 9, pulses are applied in the order of a, b, and c, but pulses may be applied in a different order.

[0201] Alternatively, the control unit (430) may configure a charging sequence to first turn on and then turn off any one of the plurality of lower arm switching elements (Sx, Sy, Sz), and then turn on and then turn off the remaining lower arm switching elements.

[0202] The charging sequence of the bootstrap circuit (530) is characterized by charging the lower switching elements (Sx, Sy, Sz) at least twice.

[0203] As an example, the first lower arm switching element (Sx) can be turned on, and the second lower arm switching element (Sy) and the third lower arm switching element (Sz) can be turned on simultaneously or sequentially. Alternatively, the first lower arm switching element (Sx) and the second lower arm switching element (Sy) can be turned on simultaneously, and the third lower arm switching element (Sz) can be turned on. However, for fault diagnosis, it is not important which leg of the lower arm switching element (Sx, Sy, Sz) of the inverter (430) is operated first.

[0204] FIG. 10 is a diagram illustrating the pulse width of an inverter lower arm switch according to one embodiment of the present disclosure.

[0205] The time for turning on each lower arm switching element (Sx, Sy, Sz) may be 0.1 to 2.3 times the time constant value of the bootstrap capacitors (Cboot1, Cboot2, Cboot3) and bootstrap resistors (Rboot1, Rboot2, Rboot3) connected to each lower arm switching element (Sx, Sy, Sz). If it exceeds 0.1 to 2.3 times, the discrimination power of fault diagnosis may decrease.

[0206] Referring to (a) of Fig. 10, it is preferable that the turn-on time of the inverter lower arm switching elements (Sx, Sy, Sz) for fault diagnosis be a pulse width at which the capacitor (Cboot) charging voltage becomes a value between 10 and 90%.

[0207] For example, referring to (b) and (c) of FIG. 10, in order to charge the bootstrap capacitor (Cboot) to a voltage of 10 to 90%, the pulse width may be 0.1Γ to 2.3Γ for the time constant (Γ = Rboot X Cboot) of the bootstrap circuit (530).

[0208] Fault diagnosis is performed before the motor (250) operates. The control unit (430) operates the lower arm switching elements (Sx, Sy, Sz) of the inverter (430) in sequence and performs fault diagnosis using measured values.

[0209] One example of a measurement value input to the control unit (430) is a current value, and is characterized by using at least one measurement value in each pulse within the switching sequence.

[0210] FIG. 11 is a diagram illustrating a switching pulse and current measurement value for charging a bootstrap capacitor according to an embodiment of the present disclosure, showing an example of a current measurement value according to a switching pulse.

[0211] Fig. 11 (a) shows the voltage of the first bootstrap capacitor (Cboot1), Fig. 11 (b) shows the measured value of the current detection unit (425), and Fig. 11 (c) shows the switching pulse.

[0212] Referring to Fig. 11, when a switching pulse is applied to the first lower arm switching element (Sx), the voltage of the first bootstrap capacitor (Cboot1) increases significantly. Thereafter, when other lower arm switching elements (Sy, Sz) are switched, the voltage of the first bootstrap capacitor (Cboot1) may increase slightly in a stepwise manner. For example, when a switching pulse is applied to the second switching element (Sy), the voltage of the first bootstrap capacitor (Cboot1) may increase slightly.

[0213] In order to detect a fault in the inverter (420) and motor (250), a simply measured current value can be utilized, but by processing and utilizing multiple sampled values ​​(P11, P12, P13, P21, P22, P23), the discrimination power of fault diagnosis can be increased. In addition, a processed value that is easy to diagnose can be used for each fault diagnosis item.

[0214] For example, the average (average of P11, P12, P13 and average of P21, P22, P23) during the entire interval, the maximum value (P11, P21), and the sum value (P11+ P12+P13, P21+P22+P23) can be used as the processing value.

[0215] Additionally, the slope, difference value, and sum of differences corresponding to the change in the measured value can be used as the processed value. For example, the difference of the sampling values ​​within the same pulse (the difference between P11 and P12, the difference between P12 and P13, the difference between P11 and P13), and the difference of the sampling values ​​of different pulses (the difference between P11 and P21) can be used.

[0216] The control unit (430) can diagnose whether the inverter (420) and the motor (250) are faulty based on any one of the average value, maximum value, sum value, difference value, and sum value of the differences of the sampled current values.

[0217] The current value measured during the charging sequence of the bootstrap circuit (530) or its processed value is used as a major factor in fault diagnosis.

[0218] As an example, in a normal circuit without a fault, the values ​​of the major factors according to the above sequence can be recorded in advance, and a fault can be determined by comparing them with the measured / processed major factor values ​​at the time of fault diagnosis (Rule base).

[0219] Alternatively, by inputting the above-mentioned major factors using machine learning or deep learning technology and outputting the cause of the failure (inverter switch opening, short circuit, Drive IC failure, and motor failure such as line-to-line short circuit, layer-to-layer short circuit, phase open, winding ground fault, demagnetization, and restraint, etc.) as a result, the cause of the failure can be determined and the defective component can be identified. For example, in the case of inverter switching element opening, the defective component is the inverter PCB, and in the case of motor line-to-line short circuit, the motor (250) can be determined as the defective component.

[0220] Below, various fault diagnosis cases are illustrated with reference to the drawings. In the motor (250) / inverter (420), even if the fault is the same (ground fault / short circuit / open circuit), various phenomena may appear depending on the fault location. Therefore, when a fault occurs, the phenomenon may appear differently depending on the location.

[0221] Hereinafter, the current detected by the current detection unit (425) may be either the measured current value itself or a value obtained by processing sampled values.

[0222] Figure 12 is a diagram illustrating a motor phase short circuit failure, and illustrates a case where a BC phase short circuit occurs.

[0223] FIG. 13 is a diagram illustrating current sensing values ​​during normal operation according to one embodiment of the present disclosure.

[0224] Figure 14 is a diagram illustrating a switching pulse for charging a bootstrap capacitor and voltage / current values ​​in the event of a motor BC phase short-circuit fault, where (a) shows voltage, (b) shows current, and (c) shows pulse.

[0225] Referring to FIGS. 12 to 14, when a motor phase short circuit fault occurs, an impedance change occurs in the circuit of FIG. 12, and accordingly, a change also occurs in the measured current pattern.

[0226] During normal operation, from the second pulse onwards, the voltage charged from the first pulse also acts, so the current value decreases. Referring to Fig. 13, the current value (1310) from the first pulse is the largest, and the current value (1330) from the third pulse is smaller than the current value (1320) from the second pulse.

[0227] Referring to Fig. 14, in the section where the first lower switching element (Sx) is turned on, the voltage of the first bootstrap capacitor (Cboot1) rises significantly.

[0228] In the section where the second lower switching element (Sy) is turned on, during normal operation, only the voltage of the second bootstrap capacitor (Cboot2) should rise significantly, but due to the phase short circuit, the voltages of both the second bootstrap capacitor (Cboot2) and the third bootstrap capacitor (Cboot3) rise significantly. Accordingly, the second current value (1420) may appear larger than the first current value (1410) and the third current value (1430).

[0229] Referring to Figure 14, when a BC phase short circuit occurs, it can be confirmed that the current size in the second pulse (ON section of Sy) is larger than when normal. In addition, it can be confirmed that the difference (slope) value in the second pulse changes significantly when the motor BC phase short circuit occurs.

[0230] In addition, it can be confirmed that the magnitude of the peak value in each pulse changes. That is, in normal, the magnitude of the current (1310) in the first pulse is larger than the current (1320) in the second pulse, but in the case of a BC phase short circuit, it can be confirmed that the magnitude of the current (1420) in the second pulse is larger than the peak value of the first pulse (1410). In this way, a fault can be detected by comparing the magnitudes of the main factors at normal times.

[0231] The control unit (430) can determine that a short-circuit failure of the motor (250) has occurred if the current (1410) detected by the current detection unit (425) in the section where the first lower arm switching element (Sx) is turned on is greater than the current (1420) detected by the current detection unit (425) in the section where the second lower arm switching element (Sy) is turned on.

[0232] In addition, the control unit (430) can determine that the motor (250) has a short-circuit failure if the current (1420) detected by the current detection unit (425) in the section where the second lower arm switching element (Sy) is turned on is greater than the current (1320) detected by the current detection unit in the section where the second lower arm switching element (Sy) is turned on during normal operation.

[0233] As another example, in the case of an AB phase short circuit, a very high current may be formed when the first lower arm switching element (Sx) is turned on. The control unit (430) can determine a phase short circuit fault based on this change in the current pattern.

[0234] Figure 15 is a diagram illustrating a motor phase open failure, and illustrates a case where phase C opens.

[0235] Figure 16 is a diagram illustrating a switching pulse for charging a bootstrap capacitor and voltage / current values ​​when a motor C-phase open fault occurs, where (a) shows voltage, (b) shows current, and (c) shows pulse.

[0236] Referring to FIGS. 15 and 16, in the section where the first lower arm switching element (Sx) is turned on, the voltage of the first bootstrap capacitor (Cboot1) rises significantly.

[0237] Meanwhile, in the section where the first lower-arm switching element (Sx) is turned on, the voltage of the second bootstrap capacitor (Cboot2) rises relatively less than the voltage of the first bootstrap capacitor (Cboot1). The voltage of the third bootstrap capacitor (Cboot3) should rise to the same level as the voltage of the second bootstrap capacitor (Cboot2), but does not rise due to the opening of phase C.

[0238] Additionally, in the section where the second lower switching element (Sy) is turned on, the voltage of the second bootstrap capacitor (Cboot2) rises significantly, and the voltage of the first bootstrap capacitor (Cboot1) rises slightly. However, the voltage of the third bootstrap capacitor (Cboot3) does not rise due to the opening of phase C.

[0239] However, in the section where the third lower switching element (Sz) is turned on, a current flowing through the DC voltage source (520), the third bootstrap capacitor (Cboot3), the third bootstrap resistor (Rboot3), and the third bootstrap diode (Dboot3) is formed, so that voltage can be charged to the third bootstrap capacitor (Cboot3).

[0240] In this way, the current value pattern also changes depending on the change in the charging state.

[0241] Referring to Fig. 16, it can be confirmed that the size of the current value (1630) and the size of the difference value in the third pulse (ON section of Sz) are larger than when normal (see Fig. 13).

[0242] The control unit (430) can determine that an open fault of a phase (C phase) corresponding to the third lower arm switching element (Sz) of the motor (250) occurs if the current (1630) detected by the current detection unit (425) in the section where the third lower arm switching element (Sz) is turned on is greater than the current (1330) detected by the current detection unit (425) in the section where the third lower arm switching element (Sz) is turned on during normal operation.

[0243] The control unit (430) can determine that, if no current is detected by the current detection unit (425) only in the section where a specific lower arm switching element is turned on, an open failure of the corresponding lower arm switching element or the gate driver (511) connected to the corresponding lower arm switching element has occurred.

[0244] Fig. 17 is a diagram illustrating an inverter switching element open failure, and Fig. 18 is a diagram illustrating a switching pulse for charging a bootstrap capacitor and a current value when an inverter switching element open failure occurs.

[0245] Figures 17 and 18 illustrate a case where an open fault occurs in the A-phase lower arm switching element, and the same phenomenon may also occur in the case of an IGBT signal open or a gate driver failure.

[0246] Referring to FIGS. 17 and 18, when an open fault occurs in phase A, no current (1810) is detected in the section where the first lower arm switching element (Sx) corresponding to phase A is turned on. Thereafter, a current (1820) is detected in the section where the second lower arm switching element (Sy) of another phase is turned on. In this case, the control unit (430) can determine that there is an open fault in the first lower arm switching element (Sx) or a fault in the inverter PCB in a wide range.

[0247] Fig. 19 is a diagram illustrating an inverter switching element short-circuit failure, and Fig. 20 is a diagram illustrating a switching pulse for charging a bootstrap capacitor and a current value when an inverter switching element short-circuit failure occurs.

[0248] Figures 19 and 20 illustrate a case where a short circuit failure occurs in the A-phase lower arm switching element, and the same phenomenon may also occur in the case of an IGBT signal short circuit or gate driver failure.

[0249] Referring to FIGS. 19 and 20, when a short circuit fault occurs in phase A, no current is detected in the section where the first lower arm switching element (Sx) corresponding to phase A is turned on. In addition, no current (1820) is detected in the section where the lower arm switching elements (Sy, Sy) of other phases are turned on. In this case, the control unit (430) can determine that there is a short circuit fault in the first lower arm switching element (Sx) or a fault in the inverter PCB in a wide range.

[0250] The control unit (430) can determine that a short circuit failure of at least one lower switching element or at least one gate driver occurs when no current is detected by the current detection unit (425) in multiple turn-on sections.

[0251] Figures 21 to 23 are drawings for reference in the description of interlayer short circuit faults and fault diagnosis of the motor.

[0252] Fig. 21 illustrates a case where a short circuit between layers of a motor (250) has occurred, Fig. 22 illustrates a normal circuit waveform, showing the current value measured by the current detection unit (425), the sum of the current values, and the sum of the differences (2210), and Fig. 23 illustrates a waveform when a short circuit between layers has occurred, showing the current value measured by the current detection unit (425), the sum of the current values, and the sum of the differences (2310).

[0253] Referring to FIGS. 21 to 23, when the coil of the motor (250) is stuck and an interlayer short circuit occurs, a change occurs in the current value pattern due to a change in impedance.

[0254] In particular, the fluctuations are clearly evident in the sum of the differences (2210, 2310). Therefore, in the diagnosis of inter-floor short circuits, using the sum of the differences can improve the fault diagnosis discrimination ability.

[0255] The control unit (430) can determine that there is an interlayer short circuit failure of the motor (250) when, in a section where one or more lower arm switching elements (Sx, Sy, Sz) are turned on, a sum of the differences (2310) of the sampled current values ​​detected by the current detection unit (425) changes from the sum of the differences (2210) during normal operation.

[0256] Figures 24 and 25 are drawings referenced in the description of cable disconnection faults and fault diagnosis. Figure 24 illustrates a case where a cable disconnection has occurred, and Figure 25 illustrates a waveform measured when a cable disconnection occurs.

[0257] Referring to Figures 24 and 25, when a cable is disconnected, the current of each sequence appears to be of the same size.

[0258] Accordingly, the control unit (430) can determine that there is a short circuit fault in the cable connecting the inverter (420) and the motor (250) if the currents detected by the current detection unit (425) are the same in the section where each lower arm switching element (Sx, Sy, Sz) is turned on.

[0259] Figures 26 and 27 are drawings referenced in the description of ground faults and fault diagnosis. Figure 26 illustrates the current loop formed when a ground fault occurs, and Figure 27 illustrates the waveform measured when a cable is disconnected.

[0260] The control unit (430) can determine whether a ground fault exists by operating a ground fault detection algorithm before bootstrap charging.

[0261] Referring to Figures 26 and 27, when insulation breakdown occurs inside the compressor, a current loop flowing to ground is formed.

[0262] When the lower switching element (Sx) is turned on in a grounding situation, current can flow through the path of Fig. 26.

[0263] At this time, the ground fault current can be detected through the current detection means (ex, Shunt) of the current detection unit (425), and when it is higher than the limit value, it can be determined as a ground fault.

[0264] Meanwhile, the motor driving device according to an embodiment of the present disclosure and the operating method of a home appliance including the same can be implemented as processor-readable code on a processor-readable recording medium. The processor-readable recording medium includes any type of recording device that stores data readable by the processor. Furthermore, the processor-readable recording medium can be distributed across network-connected computer systems, so that the processor-readable code can be stored and executed in a distributed manner.

[0265] Although the preferred embodiments of the present disclosure have been illustrated and described above, the present disclosure is not limited to the specific embodiments described above, and various modifications may be made by a person having ordinary skill in the art to which the present disclosure pertains without departing from the gist of the present disclosure as claimed in the claims.

Claims

1. A converter that converts input AC power into DC power and outputs it; A DC capacitor storing the above DC power; An inverter having a plurality of upper and lower arm switching elements connected in series, and converting direct current power from the DC terminal capacitor into alternating current power to drive a motor; A current detection unit disposed between the DC capacitor and the inverter; Gate drivers for driving switching elements included in the above inverter, and Bootstrap capacitors that are charged according to the turn-on of the lower arm switching element and supply a driving voltage to the gate driver of the upper arm switching element; and A control unit that controls the inverter based on the current detected by the current detection unit; Before driving the above motor, The above control unit, First, some of the above multiple lower switching elements are turned on and then turned off, A motor drive device that turns on and off other lower switching elements.

2. In paragraph 1, The above control unit, A motor driving device that sequentially turns on and off the above-described plurality of lower arm switching elements one by one.

3. In paragraph 1, The above control unit, First, turn on and then turn off any one of the above multiple lower switching elements, A motor drive device that turns on and off the remaining lower switching elements.

4. In paragraph 1, A DC voltage source supplying power to the above bootstrap capacitors; and A motor drive device further comprising bootstrap resistors forming a path for current flowing from the DC voltage source to the bootstrap capacitors.

5. In paragraph 4, A motor drive device further comprising bootstrap diodes connected in series with the above bootstrap resistors.

6. In paragraph 1, The time to turn on each lower switching element is, A motor drive device having a time constant of 0.1 to 2.3 times the value of the bootstrap capacitor and bootstrap resistor connected to each lower switching element.

7. In paragraph 1, The above control unit, A motor driving device that diagnoses whether the inverter and the motor are faulty based on the current detected by the current detection unit.

8. In paragraph 7, The above control unit, A motor driving device that diagnoses whether the inverter and the motor are faulty based on a sampled current value from the current detected by the current detection unit in a section where the above-mentioned lower arm switching element is turned on.

9. In paragraph 8, The above control unit, A motor driving device that diagnoses whether the inverter and the motor are faulty based on any one of the average value, maximum value, sum value, difference value, and sum value of the differences of the sampled current values ​​from the current detected by the current detection unit in the section where the above-mentioned lower-arm switching element is turned on.

10. In paragraph 7, The above control unit, In the section where the first lower switching element is turned on, the current detected by the current detection unit is In the section where the second lower switching element is turned on, if the current detected by the current detection unit is greater than that detected by the current detection unit, A motor drive device that determines that the above motor has a short-circuit failure.

11. In paragraph 7, The above control unit, In the section where the second lower switching element is turned on, the current detected by the current detection unit is During normal operation, if the current detected by the current detection unit is greater than the current detected in the section where the second lower arm switching element is turned on, A motor drive device that determines that the above motor has a short-circuit failure.

12. In paragraph 7, The above control unit, In the section where the third lower switching element is turned on, the current detected by the current detection unit is During normal operation, if the current detected by the current detection unit is greater than the current detected in the section where the third lower arm switching element is turned on, A motor driving device that determines an open-phase fault corresponding to the third lower arm switching element of the above motor.

13. In paragraph 7, The above control unit, A motor driving device that determines that an open fault of a corresponding lower arm switching element or a gate driver connected to a corresponding lower arm switching element exists when no current is detected in the current detection section only in the section where the lower arm switching element is turned on.

14. In paragraph 7, The above control unit, A motor driving device that determines that a short-circuit failure of at least one lower arm switching element or at least one gate driver occurs when no current is detected in the current detection section during a plurality of turn-on sections.

15. In paragraph 7, The above control unit, In the section where the above-mentioned lower switching element is turned on, the sum of the differences of the sampled current values ​​from the current detected by the current detection unit is During normal driving, if there is a change in the sum of the differences, A motor drive device that determines that the above motor has a short circuit failure between layers.

16. In paragraph 7, The above control unit, If the currents detected by the current detection unit are the same in the section where each lower switching element is turned on, A motor driving device that determines a short circuit failure in a cable connecting the inverter and the motor.

17. A converter that converts input AC power into DC power and outputs it; A DC capacitor storing the above DC power; An inverter having a plurality of upper and lower arm switching elements connected in series, and converting direct current power from the DC terminal capacitor into alternating current power to drive a motor; A current detection unit disposed between the DC capacitor and the inverter; Gate drivers for driving switching elements included in the above inverter, and Bootstrap capacitors that are charged according to the turn-on of the lower arm switching element and supply a driving voltage to the gate driver of the upper arm switching element; and A control unit that controls the inverter based on the current detected by the current detection unit; Before driving the above motor, The above control unit, Charge the bootstrap capacitors sequentially, In the section where each bootstrap capacitor is charged, based on the current detected by the current detection unit, A motor driving device that diagnoses whether the inverter and the motor are faulty.

18. A home appliance having a motor drive device according to any one of claims 1 to 17.

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