Apparatus for diagnosing disconnection

Abstract

An apparatus for diagnosing disconnection according to an embodiment of the present invention comprises: a three-phase power connection line for supplying power to a motor; a duty detection circuit for detecting a duty of each phase of the three-phase power connection line; and a control unit for receiving the duty of each phase output from the duty detection circuit to determine whether each phase is disconnected.

Description

Single-line diagnostic device

[0001] The present invention relates to a single-line diagnostic device.

[0002] A hybrid electric vehicle (HEV) or plug-in hybrid vehicle (PHEV) is a vehicle that efficiently combines two or more different power sources to propel the vehicle. Most commonly, this refers to a vehicle powered by a fuel-powered engine and a battery-powered electric motor. HEVs or plug-in hybrid vehicles (PHEVs) are gaining attention as a means to address environmental pollution and improve energy efficiency.

[0003] A plug-in hybrid electric vehicle (PHEV) is a vehicle that is equipped with both a gasoline-powered internal combustion engine and a battery engine like a conventional hybrid vehicle, and can be powered by one or both of them. It is also equipped with a large-capacity, high-voltage battery that can be charged with electricity. It has the advantage of being able to be used continuously because it can be charged with electricity at home or at a charging station just like charging a cell phone or filling up with gasoline.

[0004] These hybrid or plug-in hybrid vehicles are essentially vehicles equipped with an engine, a motor, a battery, and a high-voltage battery. They propel the vehicle by driving an electric motor using electrical energy supplied by the battery. These electric motors typically require alternating current (AC) power, but the vehicle's onboard battery supplies direct current (DC) power.

[0005] To operate an electric motor, direct current is converted into alternating current to supply three-phase power. To ensure safety and reliability, three-phase short-circuit diagnosis is required.

[0006] The technical problem to be solved by the present invention is to provide a short circuit diagnosis device that diagnoses a short circuit in a three-phase motor using a hardware circuit.

[0007] In order to solve the above technical problem, a single-phase diagnosis device according to one embodiment of the present invention includes: a three-phase power connection line supplying power to a motor; a duty detection circuit detecting the duty of each phase of the three-phase power connection line; and a control unit receiving the duty of each phase output from the duty detection circuit and determining whether each phase is single-phase.

[0008] In addition, the duty detection circuit may include a first resistor connected to the power connection line of each phase, a first sensing resistor connected in series with the first resistor, and a comparator connected to a node between the first resistor and the first sensing resistor and comparing the voltage of the first sensing resistor with a first reference voltage.

[0009] Additionally, the result of the comparator may have a duty value when the voltage of the first sensing resistor is greater than the first reference voltage.

[0010] In addition, it includes a switching unit that supplies power to each of the three-phase power connection lines, and the first reference voltage can be generated by dividing the voltage of a DC power source that supplies power to the switching unit.

[0011] Additionally, the first reference voltage can be generated through voltage division of a second resistor having a resistance value corresponding to the first resistor and a third resistor having a resistance value corresponding to the first sensing resistor and connected in series with the second resistor.

[0012] In addition, the control unit can calculate the phase voltage of each phase using the duty of each phase, determine whether the phase voltage of each phase matches a first reference value, and determine a disconnection if the phase voltage does not match for a predetermined period of time or longer.

[0013] In addition, it includes a switching unit that supplies power to each of the three-phase power connection lines, and the first reference value may be half the voltage of the DC power supply that supplies power to the switching unit.

[0014] In addition, the control unit can calculate the phase voltage of each phase according to the duty time of each phase.

[0015] Additionally, the control unit can externally provide a short circuit warning when it determines that there is a short circuit.

[0016] In addition, the control unit can determine whether each phase is disconnected using the duty detection circuit when the motor is driven, and when the motor is not driven, can apply a disconnection detection signal to the three-phase power connection line and determine whether there is a disconnection using a change according to the disconnection detection signal reflected in a signal output from the motor.

[0017] According to embodiments of the present invention, a simple hardware circuit can be added to diagnose motor failure. This saves time and money and enhances vehicle stability and reliability. Furthermore, this circuit, along with a software-based motor failure diagnosis sequence, can be applied to products requiring high ASIL levels by determining motor failure diagnosis based on redundancy.

[0018] FIG. 1 is a block diagram of a single-line diagnostic device according to one embodiment of the present invention.

[0019] Figure 2 is a block diagram of a single-line diagnostic device according to an embodiment of the present invention.

[0020] Figures 3 and 4 illustrate circuit diagrams of a single-line diagnostic device according to an embodiment of the present invention.

[0021] Figure 5 is a flowchart of a single-line diagnosis process of a single-line diagnosis device according to an embodiment of the present invention.

[0022] Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the attached drawings.

[0023] However, the technical idea of ​​the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of ​​the present invention, one or more of the components between the embodiments can be selectively combined or substituted for use.

[0024] In addition, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, may be interpreted in consideration of the contextual meaning of the relevant technology.

[0025] Additionally, the terms used in the embodiments of the present invention are intended to describe the embodiments and are not intended to limit the present invention.

[0026] In this specification, the singular may also include the plural unless specifically stated otherwise in the phrase, and when it is described as “A and / or at least one (or more) of B, C”, it may include one or more of all combinations that can be combined with A, B, C.

[0027] Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only intended to distinguish the components from other components, and are not intended to limit the nature, order, or sequence of the components.

[0028] And, when a component is described as being 'connected', 'coupled', or 'connected' to another component, it may include not only cases where the component is 'connected', 'coupled', or 'connected' directly to the other component, but also cases where the component is 'connected', 'coupled', or 'connected' by another component between the component and the other component.

[0029] Additionally, when described as being formed or arranged "above" or "below" each component, "above" or "below" includes not only cases where the two components are in direct contact with each other, but also cases where one or more other components are formed or arranged between the two components. Furthermore, when expressed as "above" or "below," the meaning may include not only the upward direction but also the downward direction based on one component.

[0030] A variation according to the present embodiment may include some components of each embodiment and some components of other embodiments. That is, a variation may include one embodiment among various embodiments, but may omit some components and include some components of the corresponding other embodiment. Or, the opposite may be true. The features, structures, effects, etc. to be described in the embodiments are included in at least one embodiment, and are not necessarily limited to just one embodiment. Furthermore, the features, structures, effects, etc. exemplified in each embodiment can be combined or modified in other embodiments by a person having ordinary skill in the art to which the embodiments belong. Therefore, the contents related to such combinations and modifications should be interpreted as being included within the scope of the embodiments.

[0031] FIG. 1 is a block diagram of a single-line diagnostic device according to one embodiment of the present invention.

[0032] FIG. 2 is a block diagram of a single-line diagnosis device according to an embodiment of the present invention, FIGS. 3 and 4 illustrate circuit diagrams of a single-line diagnosis device according to an embodiment of the present invention, and FIG. 5 is a flowchart of a single-line diagnosis process of a single-line diagnosis device according to an embodiment of the present invention.

[0033] A single-line diagnosis device according to an embodiment of the present invention is composed of a three-phase power connection line (110), a duty detection circuit (120), and a control unit (130), and may include a voltage distribution circuit (121), a comparator (122), a power supply unit (150), a switching unit (140), and a communication unit (not shown).

[0034] A short circuit diagnosis device according to an embodiment of the present invention may be a short circuit diagnosis device included in a motor drive unit that drives a motor and diagnoses a short circuit in the motor. Here, the motor drive unit may be a motor drive unit or inverter of a motor mounted on a vehicle. The vehicle may be an EV or HEV vehicle that utilizes a high-voltage system.

[0035] The three-phase power connection line (110) is composed of three lines that supply power to the motor (200). At this time, each phase can be U, V, and W phase, and can supply power to the motor (200) with a phase difference of 180 degrees. The motor (200) can be a three-phase motor. The three-phase motor includes a rotor made of permanent magnets and a stator on which three coils, that is, U-phase, V-phase, and W-phase coils, are wound. When current is supplied to the U-phase, V-phase, and W-phase coils wound on the stator, the U-phase, V-phase, and W-phase coils generate magnetic fields according to the supplied current, thereby rotating the rotor made of permanent magnets, thereby driving the motor.

[0036] The three-phase power connection line (110) can be connected to the output of the switching unit (140) that receives power from the power supply unit (150) and supplies three-phase power to the motor (200).

[0037] The power supply unit (150) can receive direct current power. The direct current power supply may be a battery or a battery installed in a vehicle. The direct current power supply may be a high-voltage direct current (HVDC). The switching unit (140) may include three upper switches and three lower switches connected in series with each upper switch. The switching unit (140) may be configured as a B6-bridge. A three-phase power connection line (110) may be connected to each node between each upper switch and each lower switch. According to the switching operation of the switching unit (140), the power input to the power supply unit (150) may be output as three-phase power to each node and supplied to the motor (200). According to the switching operation of the switching unit (140), the three-phase voltage may be converted into an alternating voltage and supplied to the motor (200).

[0038] Short-circuit diagnosis of three-phase motors operating at high voltages is essential for safety and reliability. While a short-circuit diagnosis signal can be applied to the motor and the resulting output signal changes can be utilized to diagnose the motor short-circuit, applying this signal can affect motor operation during normal operation, potentially requiring the use of motor idle periods.

[0039] A short circuit diagnosis device according to an embodiment of the present invention can diagnose a short circuit even while the motor (200) is operating normally by using a duty detection circuit (120).

[0040] The duty detection circuit (120) detects the duty of each phase of the three-phase power connection line (110). Here, the duty is the time during which the voltage of each phase is higher than the reference voltage within one cycle, and the duty detection circuit (120) can detect the duty of each phase. The cycle of the duty is the time during which power is applied to the U, V, and W phases in that order, and may be the time from the start time of the voltage of phase U to the next start time. Alternatively, it may be a control cycle during which the control unit (130) controls the switching unit (140).

[0041] The process by which the duty detection circuit (120) detects the duty of each phase will be described in detail later.

[0042] The control unit (130) receives the duty of each phase output from the duty detection circuit (120) and determines whether each phase is open-circuited. The control unit (130) can receive the duty of each phase from the duty detection circuit (120). The control unit (130) can receive Duty_U, Duty_V, and Duty_W, which are the duties of the U, V, and W phases, respectively. The control unit (130) can calculate the phase voltage of each phase using the duty of each phase. The control unit (130) calculates the phase voltage instead of the line voltage using the duty of each phase, thereby enabling individual open-circuit diagnosis for each phase. The phase voltage is the voltage applied to the U, V, and W phases, and the line voltage means the voltage between UV, the voltage between VW, and the voltage between WU.

[0043] The duty detection circuit (120) may include a voltage division circuit (121) and a comparator (122). The voltage division circuit (121) may include a first resistor (R1) and a first sensing resistor (R_sen) connected to a power connection line of each phase. As shown in FIG. 3, the first resistor (R1) and the first sensing resistor (R_sen) may be connected in series and connected to the power connection lines of each phase. The first-first resistor and the first-first sensing resistor may be connected in series to the U-phase power connection line, the first-second resistor and the first-second sensing resistor may be connected in series to the V-phase power connection line, and the first-third resistor and the first-third sensing resistor may be connected in series to the W-phase power connection line. Each first sensing resistor (R_sen) may be connected to a ground. Here, the ground may be a ground (HV GND) of a high voltage section.

[0044] A comparator (122) may be connected to a node between a first resistor (R1) and a first sensing resistor (R_sen). The voltage of each three-phase power connection line is voltage-divided through the first resistor (R1) and the first sensing resistor (R_sen) connected in series, and the voltage across the first sensing resistor (R_sen) may be applied as an input to the comparator (122). The first sensing resistor (R_sen) may have a lower resistance value than the first resistor (R1), and may reduce the magnitude of the voltage of each three-phase power connection line and apply it to the comparator (122).

[0045] The comparator (122) can compare the voltage of the first sensing resistor (R_sen) with the first reference voltage. The comparator (122) can compare the voltage of the first sensing resistor (R_sen) with the first reference voltage (Vph_DC) and output a signal according to the comparison result. At this time, the signal output from the comparator (122) corresponds to the duty of each phase. That is, the comparator (122) can output the duty of each phase.

[0046] As a result of the comparison of the comparator (122), if the voltage of the first sensing resistor (R_sen) is greater than the first reference voltage (Vph_DC), a first value can be output, and if the voltage of the first sensing resistor (R_sen) is not greater than the first reference voltage (Vph_DC), a second value can be output. The duty of each phase can be output through the ratio at which the first value is output.

[0047] In the normal state, the phase voltage has a trigonometric waveform, and the voltage of the first sensing resistor (R_sen) also has a trigonometric waveform, and when the voltage is greater than the first reference voltage (Vph_DC) in the increasing direction, a first value corresponding to on is output, and when the voltage is less than the first reference voltage (Vph_DC) in the decreasing direction, a second value corresponding to off is output, and the first value is maintained for a certain period of time, so that the duty of the corresponding phase can be output accordingly. The first reference voltage (Vph_DC) can be set to a voltage value applied as a voltage division ratio of the first resistor (R1) and the first sensing resistor (R_sen) for 1 / 2 of the maximum voltage of each phase voltage in the normal state. Alternatively, it can be set to 1 / 3 to 2 / 3.

[0048] The first reference voltage (Vph_DC) can be generated through a reference voltage generation circuit (160) connected to the power supply unit (150). The first reference voltage (Vph_DC) can be generated by dividing the voltage of the DC power applied to the power supply unit (150). The first sensing resistor (R_sen) is a value whose size is reduced through voltage division, and thus the first reference voltage (Vph_DC) can also be generated through voltage division of the voltage of the DC power applied to the power supply unit (150). The reference voltage generation circuit (160) can include a second resistor (R2) and a third resistor (R3) connected in series, as shown in Fig. 4. The first reference voltage (Vph_DC) can be generated through voltage division of the second resistor (R2) and the third resistor (R3) connected in series. The second resistor (R2) and the third resistor (R3) may be formed with values ​​for generating the first reference voltage (Vph_DC). For example, the second resistor (R2) and the third resistor (R3) may be implemented so that the first reference voltage (Vph_DC) is a voltage value applied with a voltage division ratio of the first resistor (R1) and the first sensing resistor (R_sen) for half the voltage of the DC power source. The second resistor (R2) may have a resistance value corresponding to the first resistor (R1), and the third resistor (R3) may have a resistance value corresponding to the first sensing resistor (R_sen). Alternatively, it is obvious that the second resistor (R2) and the third resistor (R3) may have different values ​​from the first resistor (R1) and the first sensing resistor (R_sen) depending on the magnitude of the first reference voltage (Vph_DC).

[0049] The control unit (130) can calculate the phase voltage of each phase using the duty of each phase. The control unit (130) can calculate the phase voltage of each phase using the duty time of each phase received from the duty detection circuit (120). The phase voltage can be calculated according to the ratio of the time that the duty is on. The time that the duty is on can vary depending on the size of the first reference voltage (Vph_DC), and the phase voltage according to the first reference voltage (Vph_DC) can be calculated using a pre-stored relational expression. That is, the phase voltage can be calculated according to the ratio of the first reference voltage (Vph_DC) and the time that the duty is on. For example, the first reference voltage (Vph_DC) is a value corresponding to half the voltage of the DC power of the power unit (150), and when the duty is 50%, the corresponding phase voltage can be calculated as half the voltage of the DC power.

[0050] The control unit (130) determines whether the phase voltage of each phase matches the first reference value, and if the mismatch occurs for a predetermined period of time or longer, it can be determined as a disconnection. The control unit (130) determines whether the phase voltage of each phase matches the first reference value, which is the phase voltage value in a normal state, and if it matches the first reference value, it can be determined as normal. If the calculated phase voltage does not match the first reference value, it is not determined as a disconnection right away, but if it continues to mismatch for a preset period of time or longer, it can be determined that a disconnection has occurred in the power connection line of the corresponding phase. For example, the control unit (130) can determine as a disconnection if the mismatch occurs for a predetermined period or longer, if it continues to mismatch for a predetermined period or longer, or if the number of mismatches exceeds a threshold.

[0051] The first reference value may be set to half the voltage of the DC power input to the power supply unit (150) that supplies power to the switching unit (140). When the voltage of the DC power supply is HVDC, the first reference value may be HVDC / 2.

[0052] If the control unit (130) determines that a short circuit exists, it can provide a short circuit warning to the user or external parties. The control unit (130) can notify an external upper controller or user of the short circuit warning through the communication unit. If the control unit (130) is in a normal state, it can control the switching unit (140) to supply three-phase power to the motor (200).

[0053] As described above, a simple hardware circuit, the duty detection circuit (120), can be used to diagnose a motor short circuit. This enables short circuit diagnosis without applying a separate sequence for motor short circuit diagnosis, saving time and cost, and enhancing the stability and reliability of devices, such as vehicles, that use the motor.

[0054] The control unit (130) determines whether each phase is disconnected using the duty detection circuit (120) when the motor (200) is driven, and when the motor (200) is not driven, it applies a disconnection detection signal to the three-phase power connection line (110) and determines whether there is a disconnection using a change according to the disconnection detection signal reflected in the signal output from the motor (200).

[0055] The control unit (130) not only diagnoses whether there is a disconnection using the duty detection circuit (120), but also applies a disconnection detection signal to the three-phase power connection line (110) using software during the idle period when the motor (200) is not driven, and determines whether there is a disconnection using a change according to the disconnection detection signal reflected in the signal output from the motor (200). The disconnection detection signal may be a PWM signal for disconnection diagnosis or a high-frequency small signal. By applying the method of using the disconnection detection signal together with the method of using the duty detection circuit (120) during the idle period of the motor (200), it is possible to determine motor disconnection diagnosis with redundancy, and apply it to products requiring a high ASIL level.

[0056] The short-circuit diagnosis process of the short-circuit diagnosis device according to an embodiment of the present invention can be performed as shown in FIG. 5. When a high-voltage direct current (HVDC) power source is applied in step S1, a first reference voltage, Vph_DC, can be generated in step S2. Here, it can be generated as Vph_DC = HVDC * R2 / (R2+R3). When the control unit (130) drives the switching unit (140) with PWM in step S3, the duty detection circuit (120) can generate Duty_U, V, W, which are the duties of each phase. At this time, the phase voltage of each phase can be voltage-divided in the voltage distribution circuit (121). Here, the voltage of each first sensing resistor can be calculated as Vph_each phase = each phase phase voltage * Rsen1 / (R1+Rsen1). Duty_U, V, W can be generated by comparing the Vph_DC calculated in step S2 with the phase voltage values ​​of each phase through a comparator (122). In step S4, the MCU, which is the control unit (130), can determine whether the phase voltage values ​​of each phase are normal values ​​using Duty_U, V, W or not, and whether the motor is disconnected. At this time, the first reference value, which is the normal phase voltage, can be HVDC / 2. As a result of determining whether there is a disconnection, if NOK, a motor disconnection warning is notified to the driver in step S6, and if OK, normal operation can be resumed in step S7.

[0057] As described above, a simple hardware circuit, the duty detection circuit (120), can be used to diagnose a motor disconnection. This enables disconnection diagnosis without applying a separate sequence for motor disconnection diagnosis, saving time and cost and improving the stability and reliability of devices, such as vehicles, that use the motor. In addition, since motor disconnection diagnosis can be determined through redundancy along with a software-based motor disconnection diagnosis sequence, it can be applied to products requiring a high ASIL level.

[0058] Meanwhile, embodiments of the present invention can be implemented as computer-readable code on a computer-readable recording medium. Computer-readable recording media include all types of recording devices that store data that can be read by a computer system.

[0059] Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, and optical data storage devices. In addition, the computer-readable recording media can be distributed across network-connected computer systems, so that computer-readable code can be stored and executed in a distributed manner. In addition, functional programs, codes, and code segments for implementing the present invention can be easily inferred by programmers in the technical field to which the present invention pertains.

[0060] Those skilled in the art will appreciate that the present invention can be implemented in modified forms without departing from the essential characteristics of the above-described description. Therefore, the disclosed methods should be considered illustrative rather than restrictive. The scope of the present invention is set forth in the claims, not the foregoing description, and all differences within the scope equivalent thereto should be construed as being encompassed by the present invention.

Claims

1. 3-phase power cable to supply power to the motor; A duty detection circuit that detects the duty of each phase of the above three-phase power connection line; and A short circuit diagnosis device including a control unit that receives the duty of each phase output from the above duty detection circuit and determines whether each phase is short circuited.

2. In paragraph 1, The above duty detection circuit, A first resistor connected to the power connection line of each of the above phases and a first sensing resistor connected in series with the first resistor; and A short circuit diagnosis device including a comparator connected to a node between the first resistor and the first sensing resistor and comparing the voltage of the first sensing resistor with a first reference voltage.

3. In paragraph 2, A short circuit diagnosis device having a duty value when the voltage of the first sensing resistor is greater than the first reference voltage as a result of the above comparator.

4. In paragraph 2, It includes a switching unit that supplies power to each of the three-phase power connection lines, The above first reference voltage is A short circuit diagnosis device generated by distributing the voltage of a direct current power source that supplies power to the above switching unit.

5. In paragraph 4, The above first reference voltage is, A short circuit diagnosis device generated through voltage division of a second resistor having a resistance value corresponding to the first resistor and a third resistor having a resistance value corresponding to the first sensing resistor and connected in series with the second resistor.

6. In paragraph 1, The above control unit, A short circuit diagnosis device that calculates the phase voltage of each phase using the duty of each phase above, determines whether the phase voltage of each phase matches a first reference value, and determines a short circuit if it does not match for a predetermined period of time.

7. In paragraph 6, It includes a switching unit that supplies power to each of the three-phase power connection lines, The above first reference value is A short circuit diagnostic device that is half the voltage of the DC power supply that supplies power to the above switching unit.

8. In paragraph 6, The above control unit, A short circuit diagnosis device that calculates the phase voltage of each phase according to the duty time of each phase.

9. In paragraph 1, The above control unit, A short circuit diagnostic device that provides a short circuit warning externally when it determines that there is a short circuit.

10. In paragraph 1, The above control unit, When the above motor is driven, the duty detection circuit is used to determine whether each phase is open, A short circuit diagnosis device that applies a short circuit detection signal to the three-phase power connection line when the above motor is not driven, and determines whether there is a short circuit by using a change according to the short circuit detection signal reflected in the signal output from the motor.

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