JP2012215514A - Test device and test method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a test device in which convenience in determining a short circuit in a motor is improved, and a test method therefor.SOLUTION: A line voltage measuring circuit 22 measures voltages between respective two lines of three phase winding lines 121 to 123, and a voltage applying circuit 20 applies an impulse signal between two phases among three phase winding lines. A response time measuring circuit 23 measures response time from the application of the impulse signal until the line voltages meet a prescribed detection threshold. Further a short circuit determination circuit 27 determines the short circuit in the motor 1 based on the total of response time of combinations of respective two phases among the three phase winding lines 121 to 123.

Description

  The present invention relates to a test apparatus and a test method, and more particularly to an improvement of a test apparatus that performs an insulation evaluation test of a winding by applying an impulse signal.

  The motor is formed by winding an insulated wire around an iron core in which electromagnetic steel plates are stacked. When the insulation of this electric wire is burned or deteriorated, a short circuit may occur between the electric wires or between the electric wire and the iron core due to poor insulation, which may lead to motor burnout or an electric shock accident. For this reason, in a product including windings such as a motor, a transformer, and an electromagnetic coil, a winding insulation evaluation test is performed for the purpose of determining a short circuit such as insulation deterioration of the winding.

  When a winding is applied to a stator or a rotor in the production process of the motor, the insulation evaluation test for the winding is performed individually. However, for example, in a compressor used in an air conditioner, a refrigerator, etc., a compressor directly connected to the stator and rotor of the motor is incorporated in a metal container, and is stored in a metal container so as to withstand the pressure of the refrigerant compressed gas, and is completely sealed. Welding is performed. In this welding process, molten metal powder, so-called spatter, scatters in the container and adheres to the winding, which may cause a short circuit of the winding. For this reason, the insulation evaluation test of the winding is performed after the welding process.

  The winding insulation evaluation test is performed, for example, by applying a high-voltage surge impulse to the three-phase winding of the motor and measuring the response signal. That is, since the impedance of the winding in which the short circuit has occurred is different from that of the winding without a short circuit (normal product), the impulse response signal shows a value different from the normal value. For this reason, a short circuit of the winding can be determined by comparing the measured response signal with a normal value.

  A three-phase motor in which a permanent magnet is incorporated in a rotor, for example, an IPM (Interior Permanent Magnet) motor is known. The IPM motor has an advantage that the number of revolutions can be easily controlled, and is used for an electric vehicle (EV). In the IPM motor, since the permanent magnet is incorporated in the rotor, the impedance of the winding varies depending on the rotation angle of the rotor. In order to perform an insulation evaluation test of such an IPM motor, it is necessary to make the rotation angle of the rotor stationary at a specific rotation position.

  As a method for stopping the rotor at a specific rotational position, a technique is known in which a direct current is passed through two specific phases of a three-phase winding. By this method, if the rotor is stationary at a specific rotational position with respect to the three-phase winding and an impulse signal is applied to the winding at this rotational position, a short circuit of the winding can be determined. However, when the insulation evaluation test is performed after the motor is attached to the apparatus, there is a problem that it is complicated to rotate the rotor. In particular, in an electric vehicle, this problem is particularly important because the vehicle moves if the rotor is rotated.

  In a three-phase motor in which a permanent magnet is not arranged on the rotor, for example, a cage-type three-phase induction motor, a cage rotor made of an aluminum bar acts as a secondary winding. For this reason, as in the case of the IPM motor, the impedance of the three-phase winding fluctuates according to the rotational position of the rotor, and there is a problem that it is not possible to determine the short circuit of the motor when the rotor is at an arbitrary rotational position. there were.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a test apparatus and a test method thereof that can improve convenience when determining a short circuit of a motor. In particular, it is an object of the present invention to provide a test apparatus that can accurately determine a short circuit such as insulation deterioration of a motor in a state where the rotor is at an arbitrary rotational position.

  A test apparatus according to a first aspect of the present invention is a test apparatus for determining a short circuit of an electric motor composed of a three-phase winding, the line voltage measuring means for measuring each line voltage of the three-phase winding, A voltage applying means for applying an impulse signal to two phases of the three-phase winding; and a response time measuring means for measuring a response time until the line voltage matches a predetermined detection threshold after applying the impulse signal; Short circuit determination means for determining a short circuit of the motor based on the sum of the response times in each combination of the two phases of the three-phase winding.

  According to such a configuration, the principle that the total response time in each combination of the two phases of the three-phase winding is constant regardless of the rotational position of the rotor is used. Judgment of short circuit. Therefore, since the short circuit of the electric motor can be determined without specifying the rotational position of the rotor, the convenience in determining the short circuit of the electric motor can be improved. In particular, it is possible to determine a short circuit of an electric motor without rotating the rotor for a product such as an electric vehicle in which it is difficult to rotate the rotor for winding insulation evaluation after the electric motor is installed.

  A test apparatus according to a second aspect of the present invention includes response time comparison means for comparing the sum of the response times with a determination threshold in addition to the above configuration, and the short-circuit determination means is based on a comparison result of the response time comparison means. Thus, the electric motor is configured to determine a short circuit.

  A test method according to a third aspect of the present invention is a test method for determining a short circuit of an electric motor composed of a three-phase winding, the line voltage measuring step for measuring each line voltage of the three-phase winding, A voltage application step of applying an impulse signal to two phases of the three-phase winding; a response time measurement step of measuring a response time until the line voltage matches a predetermined threshold after the application of the impulse signal; A short-circuit determining step for determining a short-circuit of the electric motor based on the sum of the response times in each combination of the two phases of the three-phase winding.

  The test apparatus and test method according to the present invention uses the principle that the sum of response times in each combination of two phases of a three-phase winding is constant regardless of the rotational position of the rotor, and based on the sum of response times, The short circuit of the motor is judged. Therefore, since the short circuit of the electric motor can be determined without specifying the rotational position of the rotor, the convenience in determining the short circuit of the electric motor can be improved. In particular, even when the electric motor is attached to an object such as an electric vehicle that makes it difficult to rotate the rotor after the electric motor is attached, it is possible to determine a short circuit of the electric motor without rotating the rotor.

1 is a circuit diagram showing a configuration example of a test apparatus according to an embodiment of the present invention, and an impulse test apparatus 100 is shown as an example of the test apparatus. It is explanatory drawing which showed the electrical equivalent circuit of the UV phase of FIG. It is explanatory drawing which showed the mode when the short circuit occurred in the coil | winding 121 of FIG. It is the figure which showed an example of operation | movement of the impulse test apparatus 100 of FIG. 1, and has shown the change of the line voltage at the time of applying an impulse signal. It is explanatory drawing which showed an example of the motor 1 with which the insulation evaluation test by the impulse test apparatus 100 of FIG. 1 is performed. It is the figure which showed an example of the operation | movement in the IPM motor of FIG. 3 is a flowchart showing an example of a short circuit determination process of the impulse test apparatus 100 of FIG. 1. It is the flowchart which showed an example of the response time measurement (step S102) of the U-V phase in FIG. It is the flowchart which showed an example of the response time measurement (step S103) of the VW phase in FIG. It is the flowchart which showed an example of the response time measurement (step S104) of the WU phase in FIG.

  FIG. 1 is a circuit diagram showing a configuration example of a test apparatus according to an embodiment of the present invention. An impulse test apparatus 100 is shown as an example of the test apparatus. The impulse test apparatus 100 is an electronic device for determining a short circuit of the motor 1, and more specifically, by applying an impulse signal to the three-phase windings 121 to 123 of the motor 1, the three-phase windings 121 to 123 are applied. The operation to determine the short circuit of The short circuit of the winding means that an insulation failure occurs between the electric wires forming the winding or between the electric wires and the iron core. For example, it includes a state in which a current flows between wires or between a wire and an iron core, and a state in which a current can flow if a high voltage such as a surge impulse is applied by carbonizing an insulating film of the wire due to heat.

  The impulse test apparatus 100 includes an IPM motor 1, switches SW2 to SW4, a voltage application circuit 20, a high voltage divider 21, a line voltage measurement circuit 22, a response time measurement circuit 23, an addition circuit 24, a response time comparison unit 25, a determination threshold value. A storage unit 26 and a short circuit determination circuit 27 are included.

  The motor 1 is an electric motor including a stator composed of three-phase windings 121 to 123, and a star connection is formed by connecting one end of each of the three-phase windings 121 to 123 to a neutral point 124. Examples of the motor 1 include a SPM motor (Surface Permanent Magnet Motor) in which a permanent magnet is disposed on the surface of a rotor, and a cage shape in which both ends of a conductive rigid body such as a plurality of aluminum bars or copper bars are connected to an annular conductor. There are squirrel-cage motors having a structured rotor. Here, it is assumed that the motor 1 is an IPM motor in which a permanent magnet is embedded in the rotor. Hereinafter, the windings 121 to 123 are U-phase, V-phase, and W-phase windings, respectively, and the U-phase, V-phase, and W-phase windings are connected to the voltage application circuit 20 via terminals 125 to 127, respectively. It shall be.

Voltage application circuit 20 is of the three-phase windings 121 to 123, a signal output means for applying an impulse signal voltage V _P to the windings of the two phases. The impulse signal refers to a voltage signal shorter than a predetermined time width, and for example, a signal of about 3000 to 5000 V is applied. Alternatively, a negative polarity signal of about −5000 to −3000 V may be applied.

  The voltage application circuit 20 includes a DC power source 201, a charging capacitor 202, and a charge / discharge switch SW1 having switching contacts SW1a and SW1b. The DC power supply 201 is a power supply device that charges the charging capacitor 202 by supplying electric charge to the charging capacitor 202 via the switching contact SW1a. The charging capacitor 202 is a capacitive element that applies an impulse signal to the two-phase winding via the switching contact SW1b.

  The charge / discharge switch SW1 is an interlocking switch composed of two open / close contacts SW1a and 1b, and is configured such that when one of the switches is on, the other is off. That is, when the switching contact SW1a is turned on, the DC power source 201 and the charging capacitor 202 are connected, the switching contact SW1b is turned off, the charging capacitor 202 and the motor 1 are disconnected, and charging is performed from the DC power source 201. The capacitor 202 is charged. Next, when the switching contact SW1a is turned off, the DC power supply 201 and the charging capacitor are cut off, the switching contact SW1b is turned on, and an impulse signal is output from the charging capacitor 202 to the motor 1. Here, on / off of the switching contacts SW1a and SW1b is switched based on a control signal of a control unit (not shown).

  The switches SW2 to SW4 are interlocking switches that turn on and off the two switching contacts in conjunction with each other. The switches SW2 to SW4 are switching parts that connect the both ends of the charging capacitor 202 to the terminals 125 to 127 of the motor 1 in a switchable manner. Specifically, the switches SW2 to SW4 are based on a control signal from a control unit (not shown). Any one of the terminals 125 to 127 is connected to both ends of the charging capacitor 202.

  The switch SW2 is an interlocking switch that interlocks the two open / close contacts SW2a and SW2b, and the connection state is switched so that the open / close contacts SW2a and SW2b coincide with each other. The switch SW2 connects or disconnects both ends of the charging capacitor 202 and the terminals 125 and 126 of the motor 1. The switch SW3 is an interlocking switch that interlocks the two open / close contacts SW3a and 3b to turn on / off, and the connection state is switched so that the on / off of the open / close contacts SW3a and SW3b coincide with each other. The switch SW3 connects or disconnects both ends of the charging capacitor 202 and the terminals 126 and 127 of the motor 1.

  The switch SW4 is an interlocking switch that interlocks the two open / close contacts SW4a and SW4b, and the connection state is switched so that the on / off of the open / close contacts SW4a and SW4b coincide with each other. By this switching, both ends of the charging capacitor 202 and the terminals 127 and 125 of the motor 1 are connected or disconnected.

  The voltage application circuit 20 applies an impulse signal to any two phases of the three-phase windings 121 to 123. That is, when the switching contact SW1b is turned on and an impulse signal is output from the charging capacitor 202, the switch SW2 is in the on state, and if the switches SW3 and SW4 are in the off state, the U-V phase winding 121 is used. And 122 are applied with impulse signals.

  Further, if the switch SW3 is in an on state and the switches SW2 and SW4 are in an off state, an impulse signal is applied to the V-W phase windings 122 and 123, respectively. If the switch SW4 is in an on state and the switches SW2 and SW3 are in an off state, an impulse signal is applied to the W-U phase windings 123 and 121, respectively.

  The high voltage divider 21 is input to the line voltage measurement circuit 22 in order to measure the signal voltage resulting from applying the impulse signal between the lines from the charging capacitor 202 via the switching contact SW1b and the switches SW2 to SW4. A voltage dividing resistor that divides the voltage into a predetermined voltage dividing ratio.

  The line voltage measurement circuit 22 is a line voltage measurement unit that measures line voltages of the three-phase windings 121 to 123. The line voltage refers to a potential difference between two terminals among terminals 125 to 127 corresponding to the three-phase windings 121 to 123, respectively. Here, the line voltage of the two-phase winding to which the impulse signal is applied is measured. For example, if the switch SW2 is in the on state and the switches SW3 and SW4 are in the off state, the U-V phase is measured. The voltage between the windings 121 and 122, that is, the potential difference between the terminals 125 and 126 is measured. Here, in order to prevent the impulse signal from being directly input to the line voltage measurement circuit 22, the line voltage of the winding is obtained based on the voltage division level by the high voltage divider 21.

  The response time measurement circuit 23 is a measurement unit that measures the response time until the line voltage of the winding coincides with a predetermined detection threshold after applying the impulse signal. The line voltage of the winding temporarily rises due to the impulse signal and then drops to 0 V or less, which is the ground voltage. At this time, the response time until the line voltage matches the detection threshold has a linear relationship with the impedance of the winding to which the impulse signal is applied. Therefore, the response time measurement circuit 23 indirectly measures the impedance of the winding by measuring the response time. Such measurement of the response time is performed for each of the three combinations of the U-V phase, the V-W phase, and the W-U phase. Here, it is assumed that the response time measurement circuit 23 measures, as the response time, the zero crossing time until the line voltage of the winding coincides with the ground voltage after applying the impulse signal.

  The adder circuit 24 is a computing means for obtaining the sum of the response times measured by the response time measurement circuit 23, and calculates the sum of the response times in each of the two-phase combinations of the three-phase windings 121 to 123. Specifically, the sum of the three response times of the U-V phase, the V-W phase, and the W-U phase is calculated.

  In addition, when a user operation is performed to instruct that the motor 1 to be tested is a standard product without a short circuit, the adder circuit 24 stores the sum of the calculated response times as a determination threshold in the determination threshold storage unit 26. To do. Here, the test apparatus designation (not shown) for the user to designate whether the impulse test apparatus 100 is a standard product or a test sample to be tested for the presence or absence of a short circuit is the impulse test apparatus 100. It shall have a switch. For example, the motor 1 without a short circuit is used as a standard product, the test piece designation switch is switched to the standard product side, the total response time is measured, and after the determination threshold is calculated, the standard motor 1 is replaced with the product under test. Then, change the test piece designation switch to the DUT side and measure the total response time.

  Further, it is more preferable that the adding circuit 24 calculates an allowable value obtained by subtracting a margin considering the variation of the specimen from the sum of the response times of the standard products as the determination threshold value. For example, the sum of response times of two or more standard products is measured, and a value obtained by subtracting 3σ (sigma) from the average value of the sum is calculated as a determination threshold value.

  The response time comparison unit 25 is a comparison unit that compares the sum of the response times calculated by the addition circuit 24 with the determination threshold value stored in the determination threshold value storage unit 26. Specifically, it is determined whether or not the sum of the response times calculated by the adding circuit 24 is smaller than the determination threshold value.

  The determination threshold value storage unit 26 is a storage device that holds a determination threshold value. For example, the determination threshold value storage unit 26 holds a determination threshold value calculated by the addition circuit 24.

  The short circuit determination circuit 27 is a determination unit that determines the short circuit of the motor 1 based on the sum of the response times calculated by the adder circuit 24. Specifically, based on the comparison result of the response time comparison unit 25, A short circuit of the motor 1 is determined. That is, if the sum of the response times of the U-V phase, the V-W phase, and the W-U phase is smaller than the determination threshold in the determination threshold storage unit 26, it is determined that the motor 1 is short-circuited. On the other hand, if the total response time is equal to or greater than the determination threshold, it is determined that the motor 1 is not short-circuited.

  Since the three-phase windings 121 to 123 form a star connection, the total impedance of the U-V phase, the V-W phase, and the W-U phase is constant regardless of the rotational position of the rotor. Furthermore, since the response time has a linear relationship with the impedance of the winding, the sum of the response times of the U-V phase, the V-W phase, and the W-U phase is constant regardless of the rotational position of the rotor. Become. Using this principle, the short circuit determination circuit 27 determines the short circuit of the motor based on the sum of the response times, so that it is possible to accurately determine the short circuit of the motor regardless of the rotational position of the rotor. For this reason, when determining the short circuit of the motor, it is not necessary to specify the rotational position of the rotor, and the convenience in determining the short circuit of the motor can be improved.

FIG. 2 is an explanatory diagram showing an electrically equivalent circuit of the U-V phase of FIG. Since the impulse signal is a signal including a high-frequency component, it is necessary to treat the impulse test apparatus 100 as a distributed constant circuit when obtaining a response to the impulse signal. That is, the windings 121 and 122 of the U-V phase, and an inductance L which is proportional to the winding, the DC resistance R, and the stray capacitance _{C C} generated between the wires of the windings 121 and 122, winding 121, It has core 30, 31 of the 122 and the stray capacitance _{C S} occurring between the wires.

Therefore, if the impulse signal from the voltage application circuit 20 is applied, the line voltage of the windings 121 and 122 of the U-V phase is vibrated by the inductance L, the stray capacitance _{C C} and _{C S,} the DC resistance R Attenuates and disappears. The V-W phase windings 122 and 123 and the W-U phase windings 123 and 121 can also be regarded as a similar equivalent circuit.

FIG. 3 is an explanatory diagram showing a state in which a short circuit has occurred in the winding 121 of FIG. The winding 121 is formed by winding an electric wire so that two or more layers are formed on the iron core 30. When a short circuit occurs in the same layer of the winding 121 or between different layers, for example, a short circuit path Q is formed between points corresponding to n rotations of the winding, and a current I flows through the short circuit path Q. Therefore, the inductance L of the winding 121, the DC resistance R, stray capacitance C _C and C _S are respectively changed, consequently will be the impedance is changed, the response of the windings 121 and 122 of the 2-phase to an impulse signal Time varies. In this way, if a short circuit occurs in the winding, the response time fluctuates. Therefore, by measuring the sum of the response times of the U-V phase, the V-W phase, and the W-U phase, Can be determined.

FIG. 4 is a diagram illustrating an example of the operation of the impulse test apparatus 100 of FIG. 1, and illustrates a change in line voltage when an impulse signal is applied. The vertical axis represents voltage, and the horizontal axis represents time. 4 (a) shows the impulse signal generated from the voltage application circuit 20 in FIG. 1, the impulse signal of the voltage V _P is generated which consists of a short duration.

FIG. 4B shows changes in the line voltage when an impulse signal is applied to the windings of the U-V phase, the V-W phase, and the W-U phase, respectively. For example, the line voltage of the windings 121 and 122 of the UV-phase takes a maximum value soaring by application of an impulse signal, 0V becomes then match the ground voltage to the zero crossing time T _UV decreases, Thereafter, the damped vibration is repeated. Further, the line voltage of the V-W phase windings 122 and 123 shows the same change as the line voltage of the U-V phase windings 121 and 122, but the zero cross time T _VW is equal to T _UV . It is shorter than that. Similarly, the zero-crossing time T _WU of the line voltage of the W-U phase windings 123 and 121 is longer than T _UV . These differences in the zero crossing time are caused by differences in the positional relationship between the permanent magnet embedded in the rotor of the motor 1 and the winding (that is, the rotational position of the rotor).

  FIG. 5 is an explanatory diagram showing an example of a motor 1 that is subjected to an insulation evaluation test by the impulse test apparatus 100 of FIG. 1, in which an IPM motor is shown. FIG. 5A schematically shows a cross section of the IPM motor. The IPM motor includes a rotor 41 having permanent magnets 131 to 134 embedded therein and a stator 42 including three-phase windings 121 to 123. The rotor 41 has the south pole facing the stator 42, the north pole facing the rotation axis of the rotor 41, the north pole facing the stator 42, and the south pole of the rotor 41. Permanent magnets 132 and 134 arranged toward the rotation shaft are alternately embedded. Here, it is assumed that four permanent magnets are embedded. The three-phase windings 121 to 123 are formed by winding an insulated wire around an iron core in which electromagnetic steel plates are stacked.

  FIG. 5B shows a state in which the rotor 41 is rotated counterclockwise from the state of FIG. 5A. FIG. 5C shows the state of FIG. The state when the rotor 41 is rotated counterclockwise is shown. In the IPM motor 1, the rotor 41 is rotationally driven by the magnetic interaction between the three-phase windings 121 to 123 and the permanent magnets 131 to 134.

  In the IPM motor 1, since the permanent magnets 131 to 134 are embedded in the rotor 41, the magnetic field around the three-phase windings 121 to 123 changes according to the rotational position of the rotor 41, and each of the windings 121 to 123 is changed. The impedance also varies. For this reason, the response time to the impulse signal also fluctuates during the winding insulation evaluation test.

  FIG. 6 is a diagram showing an example of the operation in the IPM motor of FIG. 5, and how the impedance changes in the U-V phase, the V-W phase, and the W-U phase when the rotation angle of the rotor is changed. Is shown. The vertical axis represents impedance, and the horizontal axis represents the rotation angle of the rotor. FIG. 6A shows a state of impedance change when each of the windings 121 to 123 is not short-circuited, and FIG. 6B shows a state of impedance change when the W-phase is short-circuited. .

  As shown in FIG. 6A, when the windings 121 to 123 are not short-circuited, the impedances of the windings of the U-V phase, the V-W phase, and the W-U phase are shifted by 120 degrees. A sine waveform is shown. For this reason, the sum of the impedances of the windings of the U-V phase, the V-W phase, and the W-U phase is constant regardless of the rotation angle of the rotor.

  On the other hand, when there is a short circuit in the W phase, the U-V phase impedance is the same as in FIG. 6A, but the V-W phase impedance slightly increases and the W-U phase impedance increases significantly. is doing. Also in this case, the windings of the U-V phase, the V-W phase, and the W-U phase each show a sine waveform, and the phases thereof are the same as those in the case where there is no short circuit. For this reason, the sum total of the impedances of the windings of the U-V phase, the V-W phase, and the W-U phase is constant regardless of the rotor rotation angle.

  Steps S101 to S110 in FIG. 7 are flowcharts showing an example of a short circuit determination process of the impulse test apparatus 100 in FIG. First, when the user switches the specimen specifying switch, it is specified whether the motor 1 to be tested is a standard product without a short circuit or a product under test for which the presence or absence of a short circuit is determined (step). S101). Next, the response time to the impulse signal is measured for the U-V phase windings 121, 122, and the V-W phase windings 122, 123 and the W-U phase windings 123, 121 are also sequentially responded. Time is measured (steps S102 to S104). Further, the adding circuit 24 calculates the sum of the response times of the U-V phase, the V-W phase, and the W-U phase (step S105).

  Further, the adding circuit 24 determines whether or not the motor 1 to be tested is a standard product (step S106). If the user specifies that the motor 1 is a standard product, the adder circuit 24 calculates a value obtained by subtracting a margin considering the variation of the test object from the sum of the response times of the motor 1 as a determination threshold value. Then, the determination threshold value is stored in the determination threshold value storage unit 26, and the process is terminated (step S109). On the other hand, if the user specifies that the motor 1 is a device under test, the response time comparison unit 25 compares the sum of the response times of the motor 1 with the determination threshold (step S107). If the sum of the response times is smaller than the determination threshold value, the short circuit determination circuit 27 determines that the motor 1 has a short circuit, and ends the process (step S108). On the other hand, if the sum of the response times is equal to or greater than the determination threshold, it is determined that there is no short circuit in the motor 1 and the process is terminated (step S110).

  Steps S201 to S205 in FIG. 8 are flowcharts illustrating an example of response time measurement (step S102) of the U-V phase in FIG. First, the U-V phase windings 121 and 122 are selected (step S201). That is, based on a control signal generated by a control unit (not shown), the switch SW2 is turned on, the switches SW3 and SW4 are turned off, and the terminals 125 and 126 of the motor 1 are connected to the voltage application circuit 20. Next, it is determined whether or not the charging of the charging capacitor 202 has been completed (step S202). If the charging of the charging capacitor 202 has been completed, the voltage application circuit 20 applies an impulse signal to the U-V phase windings 121 and 122 (step S203). Further, the response time measurement circuit 23 determines whether or not the line voltage of the U-V phase windings 121 and 122 to which the impulse signal is applied matches the predetermined detection threshold (step S204). If the line voltage matches the detection threshold, the time from when the impulse signal is applied until that point is stored as the response time, and the process is terminated (step S205).

  Steps S301 to S305 in FIG. 9 are flowcharts illustrating an example of V-W phase response time measurement (step S103) in FIG. In this flowchart, an impulse signal is applied to the windings 122 and 123 of the V-W phase instead of the windings 121 and 122 of the U-V phase, and the response time to the impulse signal is measured. Since this is the same as steps S201 to S205 in FIG.

  Steps S401 to S405 in FIG. 10 are flowcharts showing an example of W-U response time measurement (step S104) in FIG. In this flowchart, an impulse signal is applied to the W-U phase windings 123 and 121 instead of the U-V phase windings 121 and 122, and a response time to the impulse signal is measured. Since this is the same as steps S201 to S205 in FIG.

  According to the present embodiment, using the principle that the sum of the response times in the two-phase combinations of the three-phase windings 121 to 123 is constant regardless of the rotational position of the rotor, The short circuit of the motor 1 is determined based on the total time. Therefore, since the short circuit of the motor 1 can be determined without specifying the rotational position of the rotor, the convenience in determining the short circuit of the motor 1 can be improved. In particular, a short circuit of the motor 1 can be determined without rotating the rotor of a product that is difficult to rotate the rotor for insulation evaluation of the winding after the motor 1 is mounted, such as an electric vehicle.

  In the present embodiment, an example in which motor 1 includes a stator including three-phase windings 121 to 123 has been described. However, the present invention is not limited to this. For example, the motor 1 includes a rotor including three-phase windings, and the impulse test apparatus 100 determines whether the rotor three-phase windings are short-circuited. It may be configured to.

  In the present embodiment, an example in which the impulse test apparatus 100 determines a short circuit of the motor 1 has been described. However, this invention is not limited to this, The structure which determines the short circuit of motors, such as a motor and a generator, may be sufficient. For example, the electric motor may be configured to determine a short circuit of a generator provided with a stator or rotor made of three-phase windings.

  In the present embodiment, the short circuit determination circuit 27 determines that the motor 1 is short-circuited if the sum of the response times of the three-phase windings 121 to 123 is smaller than the determination threshold value. Although an example in which it is determined that the motor 1 is not short-circuited has been described, the present invention is not limited to this. For example, a second determination threshold value that is larger than the first determination threshold value for determining a short-circuit of the winding is defined, and the disconnection (open) of the winding is determined based on the second determination threshold value. May be. That is, if the total response time is smaller than the first determination threshold, it is determined that the winding is short-circuited, and if the total response time is larger than the second determination threshold, the winding is disconnected. If the total response time is equal to or greater than the first determination threshold and equal to or less than the second determination threshold, it is determined that the winding is neither short-circuited nor disconnected.

  In this case, the sum of the response times of the three-phase windings 121 to 123 is obtained for two or more standard products, and the value obtained by subtracting 3σ (sigma) from the average value of these sums is used as the first determination threshold value. It is desirable that a value obtained by adding 3σ to the average value of the sum of the values is used as the second determination threshold value.

  In the present embodiment, an example in which an impulse signal is applied to the windings of the U-V phase, the V-W phase, and the W-U phase and the response time is measured has been described. It is not limited to the structure which measures a response time 3 times in total. For example, after measuring the response time of the windings of the U-V phase, the V-W phase, and the W-U phase, the response time is measured again by applying the impulse signal in the reverse direction and measuring the response time again. The structure which measures once may be sufficient.

  In the present embodiment, an example has been described in which a short circuit of the motor 1 is determined based on the sum of response times with respect to the impulse signal. However, the present invention is not limited to this. For example, the impedances of the three-phase windings 121 to 123 are obtained by an impedance measuring device, and the sum of the impedances of the three-phase windings 121 to 123 is compared with a determination threshold value. By doing so, the structure which determines the short circuit of the motor 1 may be sufficient. That is, since the sum of the impedances of the three-phase windings 121 to 123 is constant regardless of the rotational position, the product under test is compared by comparing the sum of the impedance of the product under test with the sum of the impedances of the standard product. The short circuit of the motor 1 can be determined.

DESCRIPTION OF SYMBOLS 1 Motor 20 Voltage application circuit 21 High voltage divider 22 Line voltage measurement circuit 23 Response time measurement circuit 24 Addition circuit 25 Response time comparison part 26 Determination threshold memory | storage part 27 Short-circuit determination circuit 30, 31 Iron core 41 Rotor 42 Stator 100 Impulse test apparatus 121-123 Winding 124 Neutral points 125-127 Terminals 131-134 Permanent magnet 201 DC power supply 202 Charging capacitor SW1 Charging / discharging switch SW2-SW4 switch

Claims (3)

A test device for determining a short circuit of an electric motor comprising three-phase windings,
A line voltage measuring means for measuring each line voltage of the three-phase winding;
A voltage applying means for applying an impulse signal to two phases of the three-phase winding;
Response time measuring means for measuring a response time until the line voltage matches a predetermined detection threshold after application of the impulse signal;
A test apparatus comprising: a short-circuit determining unit that determines a short-circuit of the electric motor based on a sum of the response times in each combination of two phases of the three-phase winding. Response time comparison means for comparing the sum of the response times with a determination threshold value,
The test apparatus according to claim 1, wherein the short circuit determination unit determines a short circuit of the electric motor based on a comparison result of the response time comparison unit. A test method for determining a short circuit of an electric motor comprising three-phase windings,
A line voltage measurement step for measuring each line voltage of the three-phase winding;
A voltage application step of applying an impulse signal to two phases of the three-phase winding;
A response time measuring step of measuring a response time until the line voltage matches a predetermined threshold after application of the impulse signal;
A test method comprising: a short-circuit determination step for determining a short-circuit of the electric motor based on a sum of the response times in each combination of two phases of the three-phase winding.

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