Fault determination apparatus and method for a vehicle electric machine

Abstract

The present invention relates to a fault determination device and method for a vehicle motor. A fault determination device of a drive device including a motor and a three-phase inverter that supplies power to the motor through three-phase electric lines can include a resistor provided in each phase of the three-phase electric lines, a voltage sensing device that senses a voltage across the resistor through a current flowing into the resistor, and a sensing controller that determines whether the resistor is faulty or the three-phase electric lines are open based on a sensed voltage of the voltage sensing device and three-phase currents and of the three-phase inverter.

Description

[0001] Cross-references to related applications

[0002] This application claims the benefit of Korean Patent Application No. 10-2020-0067234, filed on June 3, 2020, with the Korean Intellectual Property Office, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to a fault determination device and method for a vehicle motor, and more specifically, to a fault determination device and method for an inverter that drives a vehicle motor. Background Technology

[0004] Typically, in order to control and drive a brushed DC motor by feeding back its current, it is necessary to detect the drive current or feedback current. In particular, in the case of a control feedback current detection method that operates by feeding back the motor current, a more accurate and stable detection circuit or detection device is required.

[0005] Hall effect current sensing is widely used to detect the current in such motors. Hall effect current sensing is a method of estimating the magnitude of the current by measuring the magnetic flux generated by the current flowing in the conductor.

[0006] Figures 1A to 1C This is a schematic diagram illustrating a fault determination method for Hall current sensing. A Hall current sensor is a sensor that senses current by sensing the current flowing into a Hall element connected to a magnetic core and outputting a sensing voltage by sensing the current.

[0007] For example, when a Hall current sensor malfunctions, the sensor's output voltage exceeds the normal range due to an open / short circuit fault, thus confirming the fault.

[0008] A current sensor can detect currents ranging from -1A to +1A by converting the current into a voltage between 0V and 5V based on the sensed voltage. For example, 0A can be measured as 2.5V.

[0009] Figure 1A This is a schematic diagram used to describe the time point when the Hall sensor is open-circuited. Figure 1B This is a schematic diagram used to describe the time point when a Hall sensor is short-circuited.

[0010] Figure 1A and Figure 1B The fault shown may occur in the sensing circuit; when the Hall sensor, such as Figure 1A When the circuit is open as shown, it can output a sensing voltage of 5V as the maximum saturation voltage; when the Hall sensor is open... Figure 1BWhen short-circuited as shown, it can output a sensing voltage of 0V.

[0011] A fault at a point in time when a Hall sensor is open-circuited or short-circuited will not have an electrical effect on the power circuit (e.g., the motor and the inverter driving the motor).

[0012] at the same time, Figure 1C It is a schematic diagram used to describe the point in time when the wires connected to power circuits such as motors and inverters are open-circuited.

[0013] like Figure 1C As shown, when the wire is open-circuited, the actual current may not flow because the power circuit is electrically isolated, so the sensed current is also 0A. When the current is fixed at 0A in a current control mode where the current reference is not 0A, this type of open-circuit fault can be identified as an open-circuit fault.

[0014] Because this Hall-type current sensor method senses the magnetic field generated by the current, its responsiveness decreases due to poor accuracy when subjected to external magnetic field interference. Consequently, the cost of the component may also increase.

[0015] Meanwhile, in recent years, the method has shifted from Hall current sensing to component current resistance sensing in order to effectively respond to large currents and reduce costs.

[0016] When a fault occurs in a shunt resistor current sensor, the output voltage of the sensing circuit is fixed to a value corresponding to "0A" (2.5V) or repeats the minimum / maximum voltage, making it difficult to apply the same fault determination method as with Hall current sensors.

[0017] Therefore, it is necessary to consider the operating characteristics of shunt resistor current sensors, and at the same time, a current sensor fault determination method that can be distinguished from traditional fault determination methods is needed. Summary of the Invention

[0018] One aspect of the present invention provides a fault determination device and a fault determination method that can determine faults and their causes by taking into account the operating characteristics of a shunt resistor current sensor.

[0019] One aspect of the present invention provides a fault determination apparatus and a fault determination method capable of resolving erroneous determinations that overlap with methods for determining the disconnection of wires connected to a motor or inverter.

[0020] The technical problems to be solved by the present invention are not limited to those described above. Those skilled in the art will clearly understand from the following description any other technical problems not mentioned herein.

[0021] According to one aspect of the present invention, a fault determination device for a drive device includes a motor and a three-phase inverter that supplies power to the motor via three-phase wires. The fault determination device may include: a resistor disposed in each phase of the three-phase wires; a voltage sensing device that senses the voltage across opposite ends of the resistor by means of the current flowing into the resistor; and a sensing controller that determines whether the resistor is faulty or whether the three-phase wires are open based on the sensed voltage of the voltage sensing device and the three-phase current of the three-phase inverter.

[0022] The sensing controller can determine whether the resistor is faulty or whether the three-phase wires are open based on whether the sensed voltage is within a predetermined fault voltage range.

[0023] When the sensed voltage exceeds the predetermined normal range, the sense controller can determine that the resistor is open.

[0024] When the sensed voltage remains above the fault voltage range within a predetermined normal range, the sense controller can determine that the resistance is normal.

[0025] When the sensed voltage remains within the fault voltage range and the sum of the three-phase currents is not equal to zero, the sense controller can determine that the resistor is short-circuited.

[0026] When the sensed voltage remains within the fault voltage range and the sum of the three-phase currents is zero, the sense controller can determine that an open circuit exists in the three-phase wires, including a wire with a resistor having the sensed voltage.

[0027] According to one aspect of the present invention, a method for determining a fault in a drive device, the drive device comprising a motor and a three-phase inverter supplying power to the motor via three-phase wires, the method comprising the following steps: sensing the voltage across opposite ends of a resistor in each phase of the three-phase wires by a voltage sensing device through current flowing into the resistor; and determining, by a sensing controller, whether the resistor is faulty or whether the three-phase wires are open-circuited based on the sensed voltage and the three-phase current of the three-phase inverter. Attached Figure Description

[0028] The above and other objects, features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0029] Figure 1A This is a schematic diagram used to describe the time point when the Hall sensor is open-circuited;

[0030] Figure 1B This is a schematic diagram used to describe the time point when a Hall sensor is short-circuited;

[0031] Figure 1CIt is a schematic diagram used to describe the point in time when the wires connected to power circuits such as motors and inverters are open-circuited;

[0032] Figure 2 This is a control block diagram of a fault determination device according to an embodiment of the present invention;

[0033] Figure 3A This is a schematic diagram illustrating the time points when the shunt resistor is open according to an embodiment of the present invention;

[0034] Figure 3B It shows when Figure 3A A schematic diagram of the inverter current when the shunt resistor is open.

[0035] Figure 4A This is a schematic diagram illustrating the time points when the shunt resistor is short-circuited according to an embodiment of the present invention;

[0036] Figure 4B It shows when Figure 4A A schematic diagram of the inverter current when the shunt resistor is short-circuited;

[0037] Figure 5A This is a schematic diagram illustrating an open-circuit wiring connection to the drive device according to an embodiment of the present invention;

[0038] Figure 5B It shows when Figure 5A A schematic diagram of the inverter current when the power supply is open.

[0039] Figure 6 This is a control flowchart describing a fault determination method according to an embodiment of the present invention; and

[0040] Figure 7 A computing system according to an embodiment of the present invention is shown. Detailed Implementation

[0041] It should be understood that the term "vehicle" or "of a vehicle" or other similar terms as used herein generally includes motor vehicles, such as passenger cars including sport utility vehicles (SUVs), buses, trucks, and various commercial vehicles, boats including various vessels and ships, aircraft, etc., and includes hybrid vehicles, electric vehicles, plug-in hybrid electric vehicles, hydrogen-powered vehicles, and other alternative fuel vehicles (e.g., vehicles powered by non-petroleum energy sources). As referred to herein, a hybrid vehicle is a vehicle with two or more power sources, such as both gasoline power and electric power.

[0042] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that when the terms “comprising” and / or “including” are used in this specification, they indicate the presence of the stated feature, value, step, operation, element, and / or component, but do not exclude the presence or addition of one or more other features, values, steps, operations, elements, components, and / or groups thereof. As used herein, the term “and / or” includes any and all combinations of one or more of the associated enumerations. Throughout the specification, unless expressly stated to the contrary, the word “comprising” and variations such as “including” or “including” will be understood to imply the inclusion of the stated element but not exclude any other element. Furthermore, the terms “unit,” “device,” “component,” and “module” described in the specification mean a unit for performing at least one function and operation, and can be implemented by hardware components or software components and combinations thereof.

[0043] Furthermore, the control logic of the present invention can be implemented as a non-volatile computer-readable medium on a computer-readable medium, which contains executable program instructions that are executed by a processor, controller, etc. Examples of computer-readable media include, but are not limited to, ROM, RAM, optical disc (CD)-ROM, magnetic tape, floppy disk, flash drive, smart card, and optical data storage device. The computer-readable medium can also be distributed across a network-connected computer system, enabling the computer-readable medium to be stored and executed in a distributed manner (e.g., via a telematics server or a controller area network (CAN)).

[0044] Hereinafter, some embodiments of the invention will be described in detail with reference to the exemplary accompanying drawings. When adding reference numerals to components in each drawing, it should be noted that the same or equivalent components are indicated by the same reference numerals even when shown in other drawings. Furthermore, in describing embodiments of the invention, detailed descriptions of well-known features or functions will be omitted to avoid unnecessarily obscuring the spirit of the invention.

[0045] In describing components according to embodiments of the present invention, terms such as first, second, "A", "B", (a), (b), etc., may be used. These terms are merely intended to distinguish one component from another, and they do not limit the nature, order, or sequence of the constituent components. Unless otherwise defined, all terms used herein (including technical or scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Such terms, as defined in a general dictionary, should be interpreted as having the same meaning as in the context of the relevant field, and should not be interpreted as having an ideal or overly formal meaning unless expressly defined as having such a meaning in this application.

[0046] Below, we will refer to Figures 2 to 6 Various embodiments of the present invention are described in detail.

[0047] Figure 2 This is a control block diagram of a fault determination device according to an embodiment of the present invention.

[0048] like Figure 2 As shown, the fault determination device can determine faults in a drive unit, which includes a motor 10, three-phase power lines 30, and a three-phase inverter 20 that supplies power to the motor 10 via the three-phase power lines 30. The fault determination device may include shunt resistors 100 connected to each phase of the three-phase power lines 30. The current flowing into the shunt resistors 100 can be sensed as an output voltage by a voltage sensing device 200. The sensing controller 300 can determine whether the shunt resistors 100 are faulty or whether the power lines 30 are open-circuited based on the sum of the sensed voltage from the voltage sensing device 200 and the three-phase currents of the inverter.

[0049] The shunt resistor 100, according to the implementation scheme, can be connected to each of the three phases of the three-phase inverter 120. Hereinafter, the shunt resistor 100 connected to phase U will be described as an example.

[0050] The wire 30 can be connected between the shunt resistor 100 and the drive device; the voltage sensing device 200 can determine the abnormal situation, i.e., the fault, by sensing the current flowing into the shunt resistor 100 and the wire 30 based on the current detection of the drive device.

[0051] like Figure 2 As shown, the shunt resistor current sensor (shunt resistor sensor) measures current by connecting a resistor between wires to allow current to flow into the resistor and by measuring the voltage across the opposite ends of the shunt resistor 100.

[0052] Compared to Hall-type current sensors, which rely on sensing the magnetic field generated by the current and are susceptible to interference from external magnetic fields, the shunt resistor 100 offers advantages in terms of higher accuracy and responsiveness. Furthermore, its cost is lower than that of a Hall sensor, making the shunt resistor 100 widely used for current sensing.

[0053] The following describes current sensing using a shunt resistor 100 connected to the drive unit.

[0054] Figure 3A This is a schematic diagram illustrating the time points when the shunt resistor is open according to an embodiment of the present invention. Figure 3B It shows when Figure 3A A schematic diagram of the inverter current when the shunt resistor is open.

[0055] like Figure 3A As shown, when the shunt resistor 100 is open, the actual power circuit (i.e., the drive unit) is open. Therefore, the actual current of the phase of the inverter with the open circuit is also 0A. In this case, since the shunt resistor 100 is open, the differential input of the voltage sensing device 200 (i.e., the sensing circuit) is determined to be "the inverter's output voltage - the motor's back electromotive force".

[0056] When a voltage (the inverter's output voltage minus the motor's back electromotive force) is applied to the sensing circuit, the voltage exceeds the normal sensing voltage range (0.5–4.5V), thus the sensing voltage is out of range. Therefore, the sensing voltage exhibits abnormal behavior (e.g., alternating between 0V and 5V values).

[0057] Figure 3B The current waveform is shown when the U-phase shunt resistor 100 is open.

[0058] As shown in the first waveform, due to the open circuit of the shunt resistor 100, the actual current of phase U becomes 0A; according to Kirchhoff's laws, the sum of the actual three-phase currents becomes zero.

[0059] However, as shown in the second waveform, the sensing current ias_SH of phase U has an alternating maximum and minimum value within the sensing range, instead of 0A. As shown in Equation 1 below, the sum of the sensing currents is "ias_SH - ias", not 0A.

[0060] [Formula 1]

[0061] The actual sum of the three-phase currents = ias + ibs + ics = 0 (ibs + ics = -ias)

[0062] The sum of the sensed three-phase currents = ias_SH + ibs_SH + ics_SH ≒ ias_SH - ias

[0063] like Figure 3B As shown in the last waveform, since the sum of the sensed three-phase currents in Formula 1 is “ias_SH-ias”, the sum of the sensed three-phase currents has a positive value when measuring the root mean square (RMS).

[0064] In other words, such as Figure 3A As shown, when the shunt resistor 100 is open, the actual current of phase U is 0A. However, the sensed voltage exhibits alternating maximum and minimum values, exceeding the predetermined normal range. This waveform indicates that the shunt resistor 100 is open.

[0065] Figure 4A This is a schematic diagram illustrating the time points when the shunt resistor is short-circuited according to an embodiment of the present invention. Figure 4B It shows when Figure 4A A schematic diagram of the inverter current when the shunt resistor is short-circuited.

[0066] like Figure 4A As shown, when the shunt resistor 100 is short-circuited, the actual power circuit (i.e., the drive unit) is short-circuited. Therefore, actual current flows into the short-circuited phase.

[0067] When the shunt resistor 100 is short-circuited, the differential input of the voltage sensing device 200 (i.e., the sensing circuit) is also electrically short-circuited, so the sensing current of the corresponding phase is always 0A. That is, in this case, current may actually flow into the shunt resistor 100, but the sensing current may become 0A; the sensing voltage can be output within a predetermined range or as a corresponding predetermined value (e.g., 2.5V).

[0068] Figure 4B The current waveform is shown when the U-phase shunt resistor 100 is short-circuited.

[0069] Similar to the first and second waveforms, the sensed current value is 0A due to the short circuit of the shunt resistor 100; however, the actual current of phase U is "-ias", not 0A.

[0070] In other words, as shown in the second waveform, the sensing current ias_SH of phase U is "-ias" instead of 0A; according to Kirchhoff's laws, the sum of the currents of the three phases becomes 0, thus establishing Formula 2.

[0071] [Formula 2]

[0072] The actual sum of the three-phase currents = ias + ibs + ics = 0 (ibs + ics = -ias)

[0073] The sum of the sensed three-phase currents = ias_SH + ibs_SH + ics_SH ≒ 0 + ibs + ics = -ias

[0074] Because the sum of the sensed three-phase currents in Formula 2 equals - "actual U-phase current", therefore... Figure 4B As shown in the last waveform, RMS is positive.

[0075] Figure 5A This is a schematic diagram illustrating an open circuit in the wiring connected to the power circuit (i.e., the drive unit) according to an embodiment of the present invention. Figure 5B It shows when Figure 5A A schematic diagram of the inverter current when the power supply is open.

[0076] like Figure 5A As shown, when a fault (error) occurs, such as an open circuit in wire 30, the actual U-phase current is 0A, and the sensed current is also 0A. In this case, because the sensed current is 0A, the result is shown as... Figure 4A The same sensing results were obtained when the shunt resistor 100 was short-circuited.

[0077] like Figure 5A As shown, when the wire 30 is open-circuited, the shunt resistor 100 is normal, therefore the sensed current and actual current of phase U can both be 0A. This can be achieved through... Figure 5B The first and second waveforms can be observed.

[0078] Furthermore, according to Kirchhoff's laws, the sum of the actual three-phase currents is 0A, and the sensed current is also 0A. Figure 5B (The third waveform in the text).

[0079] As described above, when a shunt resistor is used to detect current, when a fault occurs, the sensing voltage of the sensing circuit (i.e., the voltage sensing device) may be fixed at a specific value corresponding to 0A, or the minimum and maximum voltages may repeat. Therefore, a situation similar to a broken wire (i.e., an open circuit) may occur. Consequently, the fault may be incorrectly identified or repaired.

[0080] According to an embodiment of the present invention, the sensing controller 300 of the fault determination device can determine whether the shunt resistor 100 and the wire 30 have failed based on the actual current, the sensed current, and the sensed voltage corresponding to the actual current and the sensed current.

[0081] Figure 6 This is a control flowchart describing a fault determination method according to an embodiment of the present invention. According to an embodiment of the present invention, reference will be made below. Figure 6 Describe the fault control methods.

[0082] First, the sensing controller 300 can determine whether the sensing voltage sensed by the voltage sensing device 200 exceeds a predetermined normal range (step S610).

[0083] When the sensed voltage exceeds the normal range, the sense controller 300 can determine that the shunt resistor 100 is open (step S620).

[0084] According to the implementation plan, the normal range can be set to 0.5–4.5V; when the sensing voltage alternates between the minimum and maximum values ​​outside the normal range, such as Figure 3B As shown, the sensing controller 300 can determine that the shunt resistor 100 is an open circuit fault.

[0085] On the other hand, when the sensed voltage is within the normal range, the sense controller 300 can determine whether the shunt resistor is faulty based on whether the sensed voltage is within the predetermined fault voltage range (step S630).

[0086] like Figure 6 As shown, the predetermined fault voltage range can be set to a specific value, such as 2.5V, or it can be set to a threshold range that includes a specific value.

[0087] When the sensed voltage does not remain within the normal range but exceeds the fault voltage range (e.g., 2.5V), the sense controller 300 can determine that the shunt resistor 100 is normal (step S640).

[0088] In other words, when the sensed voltage is within the normal range and is not the sensed voltage output when the sensed current is 0A, the sense controller 300 can determine that the shunt resistor 100 is in a normal state without a fault.

[0089] However, when the sensed voltage remains within the fault voltage range, the sense controller 300 may additionally consider the three-phase current of the inverter 120 and whether it is 0A to distinguish between a short circuit in the shunt resistor 100 and an open circuit in the wire 30 (step S650).

[0090] In other words, the sensing controller 300 can determine whether the shunt resistor 100 is short-circuited or whether a fault has occurred in the wire 30 based on whether the sensed voltage is within a predetermined fault voltage range.

[0091] When the sensed voltage remains within the fault voltage range and the sum of the three-phase currents is not equal to zero, the sense controller 300 can determine that the shunt resistor 100 is short-circuited (step S660).

[0092] like Figure 4B As shown, when the shunt resistor 100 is short-circuited, the actual current measured in the wire 30 flowing into phase U is not 0A, and the sensing current of the shunt resistor 100 is 0A.

[0093] On the other hand, when the sensed voltage remains within the fault voltage range and the sum of the three-phase currents is equal to zero, the sense controller 300 can determine that the wire 30 is open (step S670).

[0094] like Figure 5B As shown, when wire 30 is open-circuited, the actual current measured in wire 30 flowing into phase U is 0A, and the sensing current of shunt resistor 100 is also 0A.

[0095] In summary, the fault determination method according to an embodiment of the present invention utilizes the shunt resistor 100 to divide the sensed voltage range at opposite ends into a normal range, a specific fault voltage range, and the sum of the three-phase currents, and determines the fault in each case. In particular, when the sum of the three-phase currents is 0A, an open-circuit fault in the wire 30 can be distinguished from a short-circuit fault in the shunt resistor 100.

[0096] Figure 7 A computing system according to an embodiment of the present invention is shown.

[0097] refer to Figure 7 The computing system 1000 may include at least one processor 1100, memory 1300, user interface input device 1400, user interface output device 1500, storage device 1600, and network interface 1700, which are interconnected via bus 1200.

[0098] Processor 1100 may be a central processing unit (CPU) or a semiconductor device that processes instructions stored in memory 1300 and / or storage device 1600. Memory 1300 and storage device 1600 may include various types of volatile or non-volatile storage media. For example, memory 1300 may include read-only memory (ROM) and random access memory (RAM).

[0099] Therefore, the operation of the methods or algorithms described in conjunction with the embodiments disclosed herein can be directly implemented as hardware or software modules executed by processor 1100, or as a combination thereof. The software modules may reside in storage media (i.e., memory 1300 and / or storage device 1600), such as RAM, flash memory, ROM, EPROM, EEPROM, registers, hard disks, removable disks, and CD-ROMs.

[0100] An exemplary storage medium can be coupled to processor 1100, and processor 1100 can read information from the storage medium and record information in the storage medium. Alternatively, the storage medium can be integrated with processor 1100. The processor and storage medium can reside within an application-specific integrated circuit (ASIC). The ASIC can reside within a user terminal. In another scenario, processor 1100 and storage medium can reside as separate components within the user terminal.

[0101] In the foregoing, although the invention has been described with reference to exemplary embodiments and accompanying drawings, the invention is not limited thereto, but can be modified and altered by those skilled in the art without departing from the spirit and scope of the invention as claimed in the appended claims.

[0102] Therefore, exemplary embodiments of the present invention are provided to explain the spirit and scope of the invention, but not to limit them; thus, the spirit and scope of the invention are not limited by these embodiments. The scope of the invention should be interpreted based on the appended claims, and all technical ideas equivalent to the scope of the claims should be included within the scope of the invention.

[0103] This technology provides a fault determination device and method that considers the operating characteristics of a shunt resistor current sensor to determine faults and their causes.

[0104] In embodiments of the present invention, fault determination apparatus and fault determination method may be provided that can resolve erroneous determinations that overlap with methods for determining the disconnection of wires connected to a motor or inverter.

[0105] In embodiments of the present invention, a fault determination apparatus and method may be provided that not only replaces the performance of conventional Hall sensors but also reduces costs by utilizing shunt resistors.

[0106] Furthermore, various effects can be provided directly or indirectly through this invention.

[0107] In the foregoing, although the invention has been described with reference to exemplary embodiments and accompanying drawings, the invention is not limited thereto, but can be modified and altered by those skilled in the art without departing from the spirit and scope of the invention as claimed in the appended claims.

Claims

1. A fault determination device for a drive device, the drive device comprising a motor and a three-phase inverter supplying power to the motor via three-phase wires, the fault determination device comprising: A resistor, which is installed in each phase of a three-phase wire; A voltage sensing device configured to sense the voltage across opposite ends of a resistor by means of a current flowing into the resistor; as well as The sensing controller is configured to determine whether a resistor is faulty or whether a three-phase wire is open-circuited based on the sensed voltage from a voltage sensing device and the three-phase current of the three-phase inverter. The sensing controller is further configured to determine whether a resistor short circuit or a three-phase wire open circuit is determined based on whether the sum of the three-phase currents is equal to zero while the sensing voltage remains within the range of the fault voltage.

2. The fault determination device for the drive device according to claim 1, wherein, When the sensed voltage exceeds the predetermined normal range, the sense controller determines that the resistor is open.

3. The fault determination device for the drive device according to claim 1, wherein, When the sensed voltage remains above the fault voltage range within a predetermined normal range, the sense controller determines that the resistance is normal.

4. The fault determination device for the drive device according to claim 3, wherein, When the sensed voltage remains within the fault voltage range and the sum of the three-phase currents is not equal to zero, the sense controller determines that the resistor is short-circuited.

5. The fault determination device for the drive device according to claim 3, wherein, When the sensed voltage remains within the fault voltage range and the sum of the three-phase currents is zero, the sense controller determines that an open circuit exists in the three-phase wires, including a wire with a resistor having the sensed voltage.

6. A method for determining a fault in a drive device, the drive device comprising a motor and a three-phase inverter supplying power to the motor via three-phase wires, the fault determination method comprising: The voltage sensing device senses the voltage across the opposite ends of the resistor in each phase of a three-phase wire by passing the current flowing into the resistor; The sensing controller determines whether there is a resistor fault or an open circuit in the three-phase wires based on the sensed voltage and the three-phase current of the three-phase inverter. Determining whether a resistor is faulty includes: The determination of whether it is a resistor short circuit or a three-phase wire open circuit is based on whether the sum of the three-phase currents is equal to zero while the sensed voltage remains within the range of the fault voltage.

7. The fault determination method according to claim 6, wherein, Determining whether a resistor is faulty includes: When the sensed voltage exceeds the predetermined normal range, an open circuit in the resistor is detected.

8. The fault determination method according to claim 6, wherein, Determining whether a resistor is faulty includes: When the sensed voltage remains above the fault voltage range within the predetermined normal range, the resistance is determined to be normal.

9. The fault determination method according to claim 8, wherein, Determining whether a resistor is faulty includes: A resistance short circuit is determined when the sensed voltage remains within the fault voltage range and the sum of the three-phase currents is not equal to zero.

10. The fault determination method according to claim 8, wherein, Determining whether a resistor is faulty includes: When the sensed voltage remains within the fault voltage range and the sum of the three-phase currents is equal to zero, an open circuit is identified in the three-phase wires, including a wire with a resistor having the sensed voltage.

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