JP6643519B1 - Motor control device and its insulation resistance detection method - Google Patents

Abstract

Provided is a motor control device that can accurately detect an insulation resistance of a motor without causing secondary damage of a semiconductor switching element and further deterioration of insulation of the motor. A motor controller (Cont1, Cont2) including switching elements (TR1 to TR12) for controlling driving of motors (1, 2) by converting a direct current into an alternating current. A current detection unit 4 for detecting a current value between a second power supply unit S2 grounded via the second switch SW0 and a bus ML to which the winding L of the motors 1 and 2 and the second power supply unit S2 are connected. (41, 42), the power supply is turned off by the first switch MS, and the current value detected by the current detection unit 4 (41, 42) when the second switch SW0 is opened and closed, respectively, and the capacitor C ( An insulation resistance calculator 3 (31, 32) for calculating insulation resistance values of the motors 1 and 2 based on the voltage values of C1 and C2) and the voltage value of the second power supply unit S2. [Selection diagram] Fig. 1

Description

  The present invention relates to a motor control device having a motor insulation resistance detection function and a method for detecting insulation resistance of a motor control device.

  A motor such as a servomotor is driven by a motor control device including an inverter, and is used for a machine tool or the like. In a machine that performs machining using a cutting fluid such as a machine tool, there is a problem in that the cutting fluid adheres to the motor, and depending on the cutting fluid, enters the motor and deteriorates the insulation of the motor.

  Further, even when used for other than machine tools, the same problem may occur when used for a long period of time or depending on the use environment.

  Motor insulation deterioration gradually progresses, eventually leading to ground fault. If the motor is grounded, the earth leakage breaker will trip or the motor control device will be damaged, leading to a system down. The system down greatly affects the factory production line. Therefore, from the viewpoint of preventive maintenance, a device that can detect the insulation resistance of the motor is desired.

  As such a method for detecting the insulation resistance of a motor, there is Japanese Patent Application Laid-Open Publication No. H11-157556. Patent Literature 1 discloses an inverter unit that is connected to a positive DC bus and a negative DC bus in a DC power source and has an arm switching element that switches connection and disconnection to and from an AC motor. A motor drive unit that converts AC power into AC power at the unit, drives a AC motor, a low-voltage source provided between one of the positive DC bus or the negative DC bus, and the ground, and one of arm switching. Detects the closed-circuit current flowing through the closed circuit including the low-voltage source, AC motor, and part of the inverter section with the elements selected and connected, and the offset current flowing through the closed circuit with all arm switching elements shut off A current detection unit, and an offset removal unit that obtains a difference value between the value of the closed circuit current detected by the current detection unit and the value of the offset current. A motor drive device comprising: an insulation resistance deterioration determining unit that determines deterioration of the insulation resistance of the AC motor by comparing a difference value based on the value of the closed circuit current with a predetermined threshold value. .

  Patent Document 2 discloses a rectifier circuit that rectifies an AC voltage supplied from an AC power supply through a first switch to a DC voltage, and a power supply unit that smoothes the DC voltage rectified by the rectifier circuit with a capacitor. An inverter for driving a motor by converting a DC voltage smoothed by a power supply into an AC voltage by a switching operation of a semiconductor switching element, and one end connected to a coil of the motor, and the other end connected to one terminal of a capacitor. A current detector for measuring a current value flowing through the connected resistor, a voltage detector for measuring a voltage value at both ends of the capacitor, a second switch for grounding the other terminal of the capacitor, and stopping the operation of the motor. Using the two sets of current and voltage values measured in the two states of turning off the first switch and turning on and off the second switch. Te, a motor drive device characterized by having an insulation resistance detector for detecting the insulation resistance of the motor is the resistance between the coil and the ground of the motor is described.

Japanese Patent No. 4961045 JP-A-2005-129704

When detecting the insulation resistance of a plurality of motors in Patent Literature 1, an offset current flowing in a closed circuit including a low voltage source, an AC motor, and a part of an inverter unit is detected in a state where all arm switching elements are shut off. When one of the arm switching elements is selected and connected, the closed circuit current flowing through the closed circuit including the low voltage source, the AC motor, and a part of the inverter unit is detected, and the value of the closed circuit current and the offset current are detected. The current based on the insulation resistance of the motor is calculated by calculating the difference between the current value and the current value. If the insulation resistance of the motor is not reduced, no offset current will flow, but if the insulation resistance of the motor is reduced, a voltage is applied to the semiconductor switching element from a low voltage source through the insulation resistance of the motor, A leakage current flows, which becomes an offset current. In Patent Literature 1, the offset current (leakage current of the semiconductor switching element) is measured, and the difference between the offset current and the measurement result of the closed circuit current when the arm switching element is selected and connected is obtained. The effect of leakage current is eliminated. However, the measured offset current is equivalent to all axes of the measurement axis and the non-measurement axis, and includes the offset current of the measurement axis. On the other hand, the current measured at the time of measuring the closed circuit current is the sum of the current based on the insulation resistance of the motor of the measurement axis and the offset current of all non-measurement axes. Therefore, if an offset is removed by calculating a difference value between the closed circuit current and the offset current,
Calculation result = Current based on insulation resistance of motor of measurement axis + Offset current of all non-measurement axis
-(Offset current of measurement axis + offset current of all non-measurement axes)
= Current based on the insulation resistance of the motor of the measurement axis−offset current of the measurement axis, resulting in an error corresponding to the offset current of the measurement axis. As described above, in the method of Patent Document 1, when the insulation resistance of the motor is reduced, the offset current of all the non-measurement axes cannot be correctly obtained, and the offset current of the measurement axis is also included. However, there is a problem that an error corresponding to the offset current of the measurement axis occurs, and the current based on the insulation resistance of the motor cannot be accurately measured.

  In Patent Document 2, as in Patent Document 1, the insulation resistance of the motor is obtained from the results of two measurements. In calculating the motor insulation resistance from the two measurement results, the influence of the leakage current of the semiconductor switching element is eliminated by eliminating the equivalent resistance corresponding to the leakage current of each semiconductor switching element. . Since there is no error of the leakage current of the measurement axis as in Patent Document 1, the measurement accuracy is higher than that of Patent Document 1. However, in the method of Patent Document 2, the voltage of the smoothing capacitor is applied to the insulation resistance of the motor. For the smoothing capacitor, an electrolytic capacitor having a relatively large capacity is used and the internal impedance is low in order to suppress a fluctuation in the DC voltage due to the power supply frequency when driving the motor. Therefore, for example, when the insulation resistance of the motor is very small and the negative element of the semiconductor switching element is short-circuited and damaged, a very large current flows from the smoothing capacitor to the semiconductor switching element through the insulation deterioration part of the motor. In addition, there is a possibility that the semiconductor switching element may be damaged secondarily, and the insulation deterioration portion of the motor may be further deteriorated.

In some cases, a bootstrap power supply is used as a gate drive power supply for a positive-side semiconductor switching element of a small-capacity inverter. Bootstrap power supply, as shown in FIG. 4, the gate drive power source _{S 3} provided in the semiconductor switching element _TR 4 to Tr ₆ on the negative side, the resistor _{R b,} diode _{D b,} positive with capacitor _{C b} And a gate drive power supply for the semiconductor switching elements TR _{1 to} TR ₃ on the side. The negative side of the semiconductor-on of the switching element _TR 4 to Tr _6, the OFF, the gate drive power source _{S 3} of the negative-side semiconductor switching element _TR 4 to Tr _6, resistor _{R b,} capacitor _{C b} is charged through the diode _{D b} Then, it becomes a gate drive power supply for the positive-side semiconductor switching elements TR _{1 to} TR ₃ . As described above, in the case where the gate drive power supplies of the positive-side semiconductor switching elements TR _{1 to} TR ₃ are configured by bootstrap power supplies, in the method of Patent Document 2, the negative-side semiconductor switching elements TR _{4 to} TR of the bootstrap power supply are used. resistance R _b of the bootstrap power from the _sixth gate drive power _supply, a diode D _b, will the current flows to the current detection resistor for insulation resistance detected through a capacitor C _b, there is a problem that the insulation resistance detection accuracy is deteriorated Was.

In some cases, instead of a bootstrap power supply, gate control signals of the semiconductor switching elements TR _{1 to} TR _{3 on} the positive side are transmitted by a high breakdown voltage IC. Thus even if such is performed transmission of the gate control signal using the high voltage IC, causes a current flows from the gate drive power source S ₃ of the negative-side current detection resistor for insulation resistance detecting through the power of the high voltage IC In addition, there is a problem that the insulation resistance detection accuracy is deteriorated.

  SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a bootstrap power supply and a high withstand voltage IC without the risk of secondary damage to a semiconductor switching element or further deterioration of insulation of a motor. An object of the present invention is to provide a motor control device that can be applied to the used motor control device and that can accurately detect the insulation resistance of the motor.

One embodiment of the present invention for solving the above problems is
A first power supply unit, a first switch that can turn off power supply from the first power supply unit, a DC supply unit that outputs power from the first power supply unit to a bus, and a first power supply unit that is connected to the bus. A capacitor and a motor control device including a switching element that converts a direct current supplied to the bus into an alternating current to drive and control a motor,
A second power supply unit having one end connected to the bus and the other end grounded via a second switch;
A current detection unit that detects a current value between the winding of the motor and the bus to which the second power supply unit is connected;
The power supply is turned off by the first switch unit, the current value detected by the current detection unit when the second switch is opened and closed, the voltage value of the capacitor, and the voltage value of the second power supply unit An insulation resistance calculation unit that calculates an insulation resistance value of the motor based on
And a motor control device comprising:

Another aspect of the present invention for solving the above-mentioned problem is:
A first power supply unit that is a non-grounded DC power supply, a DC supply unit that outputs power from the first power supply unit to a bus, a capacitor connected to the bus, and a DC supplied to the bus. A motor control device provided with a switching element for driving and controlling the motor by converting the
A second power supply unit having one end connected to the bus and the other end grounded via a second switch;
A current detection unit that detects a current value between the winding of the motor and the bus to which the second power supply unit is connected;
Based on the current value detected by the current detection unit at the time of opening and closing the second switch, and the voltage value of the capacitor and the voltage value of the second power supply unit, the insulation resistance value of the motor is determined. An insulation resistance calculator for calculating,
And a motor control device comprising:

Still another embodiment of the present invention for solving the above-mentioned problem,
A first power supply unit, a first switch that can turn off power supply from the first power supply unit, a DC supply unit that outputs power from the first power supply unit to a bus, and a first power supply unit that is connected to the bus. A capacitor, and a method for detecting the insulation resistance of a motor control device including a switching element that converts a direct current supplied to the bus into an alternating current to drive and control a motor,
Turning off the power supply by the first switch,
A second power supply unit having one end connected to the bus and the other end grounded via a second switch, wherein the second switch is opened, and the bus of the motor and the second power supply are connected; And a first current value between
The second switch is closed, and a second current value between the winding of the motor and the bus to which the second power supply unit is connected is detected by the current detection unit.
Calculating an insulation resistance value of the motor based on the detected first current value and the detected second current value, and a voltage value of the capacitor and a voltage value of the second power supply unit;
A method for detecting insulation resistance of a motor control device.

Still another embodiment of the present invention for solving the above-mentioned problem,
A first power supply unit that is a non-grounded DC power supply, a DC supply unit that outputs power from the first power supply unit to a bus, a capacitor connected to the bus, and a DC supplied to the bus. A method for detecting the insulation resistance of a motor control device comprising a switching element for driving and controlling the motor by converting the
A second power supply unit having one end connected to the bus and the other end grounded via a second switch, wherein the second switch is opened, and the bus of the motor and the second power supply are connected; And a first current value between
The second switch is closed, and a second current value between the winding of the motor and the bus to which the second power supply unit is connected is detected by the current detection unit.
Calculating an insulation resistance value of the motor based on the detected first current value and the detected second current value, and a voltage value of the capacitor and a voltage value of the second power supply unit;
A method for detecting insulation resistance of a motor control device.

  Other aspects of the present invention will be apparent from the following description of embodiments of the present invention.

  According to the present invention, the power supply from the first power supply unit is stopped by turning off the power supply by the first switch unit. In this state, when the second switch is opened, a leakage current flows through the switching element only by the voltage of the capacitor, and the first current value is detected by the current detection unit. On the other hand, similarly, when the second switch is closed in a state where the power supply from the first power supply unit is stopped, the winding of the motor using only the first current value and the voltage of the second power supply unit is changed. The second current value to which most of the passing current (the remainder is a minute leakage current of the negative switching element) is added is detected by the current detection unit. The calculation is performed based on both current values detected by the current detection unit, that is, the first current value and the second current value, and the voltage value of the capacitor and the voltage value of the second power supply unit. The value can be calculated with high accuracy.

  Here, when the first power supply unit is a DC power supply that is not grounded, the first switch unit is not provided, and there is no step of turning off the power supply by the first switch unit. Works the same.

  Further, according to the present invention, since the current value passing through the winding of the motor is measured using the voltage value of the second power supply unit, the motor is driven to use the voltage value of the capacitor for detecting insulation resistance. It is not necessary to close the switching element by performing gate drive control of the switching element to be controlled, and the current capacity of the second power supply unit can be set to a small current capacity required for insulation resistance detection. At the time of measurement, there is no possibility that a very large current flows from the capacitor to the negative-side switching element through the insulation-deteriorated portion of the motor, causing secondary damage to the switching element and further deteriorating the motor-deteriorated portion.

  Further, according to the present invention, even when the switching element for controlling the driving of the motor is driven by a bootstrap power supply or a high-voltage IC, it can be applied only by stopping the power supply. By performing the calculation in the same manner as described above, the insulation resistance value of the motor can be accurately calculated.

  Here, the “first switch” includes any switch including a circuit breaker, and can be configured to turn off the power supply from the power supply even if the terminal or the contact is in contact with the battery or the terminal of the power supply. If so, it shall be included. The “DC supply unit” naturally includes not only a power converter that converts AC to DC, but also a power converter that converts or maintains a voltage or the like from DC to DC. When a DC power supply is directly connected, the connection wires, contacts, terminals, and the like constitute a “DC supply unit”. In addition, the term "switch" includes the above-mentioned "switch", and may be anything as long as the current can be stopped, and includes a mechanical switch, a relay, a semiconductor switch, and the like.

  As described above, in the present invention, the motor control device can be applied to a motor control device using a bootstrap power supply or a high-withstand-voltage IC without secondary damage to the switching element or further deterioration of the insulation of the motor. Further, it is possible to provide a motor control device capable of accurately detecting the insulation resistance of the motor.

FIG. 2 is a circuit diagram showing a first embodiment of the motor control device of the present invention. FIG. 4 is a circuit diagram showing a second embodiment of the present invention using a bootstrap power supply in the motor control device of the present invention. FIG. 4 is a circuit diagram showing a third embodiment of the present invention using a high withstand voltage IC for driving a switching element in the motor control device of the present invention. Circuit diagram showing an example of a conventional motor control device

  FIG. 1 shows a first embodiment of the present invention.

  In the following description, current is a current value, voltage is a voltage value, impedance is an impedance value, and resistance can include a resistance value, and should be interpreted according to technical common sense of those skilled in the art. I do. Further, as for the gate drive power supply of the semiconductor switching element, since a normal insulated power supply is used unless otherwise specified, the details are omitted.

Motor controller _{C ONT1} includes a rectifier circuit (DC supply _{unit) S DC,} line ML of the positive side of the line ML ₊ and negative _- and consisting line ML, a smoothing capacitor (capacitor) _{C 1,} the semiconductor switching element TR an inverter composed of ₁ to Tr _6, made of an insulating resistance calculating unit _{3 1} Tokyo.

Motor controller C _ONT1, the electromagnetic contactor (first switch) via a MS three-phase AC power source (first power supply unit) rectifier three-phase AC voltage supplied from the S ₁ that is capable of turning off the power supply and outputs a DC voltage by full-wave rectifying the line ML by (DC supply unit) S _DC.

The output DC voltage, line ML of the positive side bus ML ₊ and the negative side of the line ML _- is smoothed by the connected smoothing capacitor (capacitor) C _1, C ₂ between.

Smoothed bus _ML +, ML _- DC voltage supplied to the positive side of the bus ML ₊ and the negative busbar ML _- is constituted by a semiconductor switching element _TR 1 to Tr ₆ that are connected between the The motor 1 is driven by an alternating current which is supplied to the inverter and supplied to the buses ML ₊ and ML ₋ by inversely converting the direct current.

Motor controller _{C ONT 2} is line ML of the positive side of the line ML ₊ and negative _- and line ML consisting, a smoothing capacitor (capacitor) _{C 2,} and the inverter composed of a semiconductor switching element _TR 7 _{to Tr 12,} It made of an insulating resistance calculating unit 3 _2.

Motor controller _{C ONT 2,} the DC voltage from the rectifier circuit _{S DC} together with the motor controller _{C ONT1} is supplied, reverse direct current into alternating current supplied to the line ML by inverter composed of a semiconductor switching element _TR 7 _{to Tr 12} It is configured to drive the motor 2 after conversion.

  This embodiment shows a configuration applied to two-axis driving in which the motor 1 and the motor 2 drive different axes, respectively.

Insulation resistance calculating unit _{3 1} of the motor control apparatus 1, the negative-side line ML of the line ML _- and a DC power supply (second power supply unit) provided between the ground E _{S 2,} the switch SW ₀ (first Switch), a current detection resistor R ₁ connected to the negative bus ML ₋ and the winding L of the motor 1, and a current from the voltage of the current detection resistor R ₁ , and controls a detection operation of the insulation resistance, Moreover, and a detection control unit (current detector) 4 ₁ Tokyo for calculating the insulation resistance values.

Insulation resistance calculating unit 3 ₂ of the motor control device 2, the negative-side line ML of the line ML _- the current from the current detection resistor R ₂ connected to the winding L of the motor _2, the voltage of the current detection resistor R ₂ detecting, also, and a detection control unit (current detector) 4 ₂ for calculating the insulation resistance values.

The current detection resistors R ₁ and R ₂ may be connected to only one phase winding L of the U-phase, V-phase and W-phase of the motors 1 and ₂ of the respective axes. Since the resistance of the winding L is very small, it is possible to detect any phase.

DC power source S ₂ is in the range of lower voltage than the voltage of the smoothing capacitor C _1, C _2, the power of the highest possible voltage, the potential of the ground E side and negative side bus ML _- used Ensure a higher state. In addition, a power supply having a very small current capacity is used as required for measurement.

To set the smoothing capacitor _{C 1,} a C _{2 of the} voltage the voltage of the DC power source _{S 2} lower than the semiconductor switching arm of inverter section from the insulation resistance _{R m1, R m @ 2} of the motor 1 at the time of measurement (positive) a current flows through the element _TR 1 _{~TR 3, TR} 7 _~TR freewheeling diode _D smoothing capacitor through _{f C} 1, _{C 2} of ₉ in the direction of charging, the detection accuracy of the insulation resistance _{R m1, R m @ 2} drops It is to prevent.

During normal motor control, switch SW ₀ is turned on the electromagnetic contactor MS remains off, the motor control of each axis is performed by an inverter. When the insulation resistance is detected, the motor control devices _Cont1 and _Cont2 are operated as follows.

Stops the motor control operation of all axes, the semiconductor switching element _TR 1 _{to Tr 12} turns off to cut off the electromagnetic contactor MS. Inverter DC voltage _{V PN} and the current detection resistor _{R 1} of the voltage _{V R1A,} measures the voltage _{V R2A} of the current detection resistor _{R 2.}

Since the voltage of the smoothing capacitor _C 1, _{C 2} is applied to the semiconductor switching element _TR 1 _{to Tr 12} constituting the inverter, the DC voltage _{V PN} inverter is substantially the smoothing capacitor _C 1, the voltage of _{C 2} equal. Such voltage, current flows through the TR ₄ from the semiconductor switching element TR _1, also, a current flows to the current detection resistor _{R 1.} Likewise current flows in _{TR 10} from the semiconductor switching element TR _7, also, a current flows to the current detection resistor _{R 2.}

Current flowing from the current and TR ₇ flows from the semiconductor switching element TR ₁ of the positive to TR ₄ to TR ₁₀ are leakage current of the semiconductor switching element. Although the leakage current flows in all phases similarly, the motor insulation resistance can be obtained by focusing on one phase to which the current detection resistors R ₁ and R ₂ are connected.

When the equivalent leakage resistance of the semiconductor switching elements of TR ₁ and TR ₄ is R _tr1, and the equivalent leakage resistance of the semiconductor switching elements of TR ₇ and TR ₁₀ is R _tr2 , the following equations (1) and (2) Holds.

_{(V PN -V R1A) / R} tr1 = V R1A / R tr1 + V R1A / R 1 ··· (1)
_{(V PN -V R2A) / R} tr2 = V R2A / R tr2 + V R2A / R 2 ··· (2)

Then turn on the switch SW _0, the negative side bus ML _- voltage _{V DC} of the DC power source _{S 2} is applied to the ground E against the current detection resistor _{R 1} of the voltage _{V R1B} and the current detection resistor _{R 2} of the voltage Measure _VR2B .

If the motor 1 is insulation deterioration, the voltage of the DC power source S ₂ is applied to the semiconductor switching element TR ₄ through the insulation resistance R _m1 of the motor, current flows to the current detection resistor R ₁ and the semiconductor switching element TR _4.

If there is likewise insulation deterioration in the motor 2, the voltage of the DC power source S ₂ is applied to the semiconductor switching element TR ₁₀ through the insulation resistance R _{m @ 2} of the motor, current flows to the current detection resistor R ₂ and the semiconductor switching element TR ₁₀ .

Further, the voltage of the smoothing capacitor _C 1, _{C 2,} namely in a state where the DC voltage _{V PN} is applied to the semiconductor switching element _TR 1, TR ₄ of the inverter, a current flows from the semiconductor switching element TR ₁ to TR _4, Moreover, current also flows to the current detection resistor R _1.

Similarly, the _{TR 10} from the semiconductor switching element TR ₇ and a current flows, also a current flows to the current detection resistor _{R 2.}

Current flowing from these semiconductor switching elements TR ₁ to _{TR 10} from current and TR ₇ flows to TR ₄ is the leakage current of the semiconductor switching element. However, the leakage current of the semiconductor switching elements, so generally small compared to the current flowing through the reduction of motor insulation resistance, voltage C _1, C ₂ of the smoothing capacitor can be assumed that almost no decrease.

  At this time, the following equations (3) and (4) hold.

_{(V PN -V R1B) / R} tr1 + (V DC -V R1B) / R m1 = V R1B / R tr1 + V R1B / R 1 ··· (3)
_{(V PN -V R2B) / R} tr2 + (V DC -V R2B) / R m2 = V R2B / R tr2 + V R2B / R 2 ··· (4)

The insulation resistance R _m1 of the motor 1 can be obtained by the following equation by solving the simultaneous equations of the equations (1) and (3).

_{R m1 = R 1 (V DC} -V R1B) (V PN -2V R1A) / {(V R1B -V R1A) V PN} ··· (5)

Further, the insulation resistance _Rm2 of the motor 2 can be obtained by the following equation by solving the simultaneous equations of the equations (2) and (4).

_{R m2 = R 2 (V DC} -V R2B) (V PN -2V R2A) / {(V R2B -V R2A) V PN} ··· (6)

These operations are performed by the detection control unit ₄ 1, _{4 2. Needless to say,} the detection of the voltages V _{R1A and} V _R2A of the current detection resistors R ₁ and R ₂ can calculate the insulation resistance values R _m1 and R _m2 by detecting each one time. One or both of the two voltages V _{R1A and} V _R2A may be measured a plurality of times, and various average values of the measured voltages may be used.

When such various average values are used, the effect of abnormal values caused by noise or the like can be reduced, and more accurate insulation resistance values R _m1 and R _m2 can be obtained.

Then, the calculated insulation resistance values R _m1 and R _m2 are transmitted to the user device as information. The transmission of the insulation resistance values R _m1 and R _m2 may be performed by any means, and may be wired transmission or wireless transmission.

The user who knows the insulation resistance values R _m1 and R _m2 judges that the insulation resistance has deteriorated when the insulation resistance value is low, and replaces the motor. It is possible to predict that the device will go down, and prevent such a problem from occurring.

  Judgment as to whether insulation resistance has deteriorated can be made by comparing it with experimentally or empirically known values, or by measuring when a motor control device is first installed using a normal product, and recording or storing it. Appropriate determination means, such as comparing with an initial value, comparing with a safety standard or other set values, can be used.

The insulation resistances R _m1 and R _{m2 of the} motors 1 and 2 are very small, and the semiconductor switching elements TR _{4 to} TR _{6 and} TR _{10 to} TR _{12 on} the negative side of the semiconductor switching elements TR _{1 to} TR ₁₂ are short-circuit damaged. If a DC power supply _S semiconductor switching element _TR 4 _{to Tr} 6 of the negative side through the insulating deteriorated part ₂ from the motor 1, _2, TR 10 _{to Tr 12} current flows, but the current capacity of the DC power source _{S 2} is Since it can be made very small as compared with the smoothing capacitors C _{1 and} C ₂ , the flowing current can be kept small.

Therefore, secondary damage and the negative-side semiconductor switching element _{TR 4 ~TR 6, TR 10 ~TR} 12 of, there is no possibility to cause insulation degradation of the further motor 1.

In the above aspect, the aspect of the present invention in the two-axis motor control device using the two motors 1 and 2 has been described. However, the present invention can be similarly applied to the case of one axis or three or more axes. It is. As the embodiment is the case, even if three or more axes, the DC power source S ₂ is sufficient be provided only in one axis.

In the embodiment, is used a three-phase AC power supply S ₁ as a first power supply unit, the first power supply unit, rather than the three-phase AC power source, it may be used single-phase AC power source. Further, in the above embodiment, a rectifier circuit is used as the DC supply unit, but a circuit that can regenerate a power supply such as a PWM converter may be used. In this case, the measurement is performed with the PWM converter stopped.

  Further, a DC power supply such as a battery may be used as the first power supply unit instead of the AC power supply. Also, a switch may be used without using an electromagnetic contactor. In addition, when power is supplied from the battery to the motor control device when the battery is mounted, a contact or a terminal itself that is electrically connected when the battery is mounted can be regarded as the first switch.

  In the case where a DC power supply such as a battery is used as the first power supply and the DC power supply itself is not grounded, the first switch becomes unnecessary in principle. In this case, the voltage of the DC power supply, the voltage of the smoothing capacitor, and the DC voltage supplied to the inverter including the semiconductor switching element are substantially the same.

Furthermore, in the above embodiment, as the motor control device C _ONT1, C _{ONT 2,} but using a three-phase inverter comprising a semiconductor switching element, when driving a single-phase motor may be used single-phase inverter. The inverter system is not limited to the above-described embodiment, and may be a full bridge or a half bridge.

  Next, an embodiment using a bootstrap power supply will be described as a second embodiment of the present invention.

As shown in FIG. 2, this aspect is applied to a case where the gate drive power supplies of the semiconductor switching elements TR _{1 to} TR _{3 and} TR _{7 to} TR ₉ on the positive side of the inverter are configured by a bootstrap power supply B. .

Bootstrap power supply B to be used as the gate drive power source of the positive side of the semiconductor switching element _TR 1 to Tr ₃ of the motor control device _{C ONT1,} the negative side of the semiconductor switching element _TR 4 to Tr gate drive power supply provided for the ₆ ( A gate drive power supply for the semiconductor switching elements TR _{1 to} TR ₃ on the positive side is configured by using a resistor R _b , a diode D _b , and a capacitor C _b in the third power supply section S ₃ .

The negative side of the semiconductor-on of the switching element _TR 4 to Tr _6, by switching off the gate drive power source _{S 3} of semiconductor switching elements on the negative side, the resistor _{R b,} the capacitor _{C b} through the diode _{D b} is charged, a gate drive power supply B for driving the positive side of the semiconductor gate of the switching element _TR 1 to Tr _3.

Further, the motor controller _{C ONT 2} also has the same configuration as the gate drive power source _{S 3} provided in the semiconductor switching elements _TR 10 _{to Tr 12} in the negative side, the resistor _{R b,} diode _{D b,} the capacitor _{C b} used to constitute the gate drive power source of the positive side of the semiconductor switching element TR ₇ ~TR _9. The operation of the gate drive power supply is the same as in the case of the motor control device _Cont1 .

In this embodiment, the motor controller C _ONT1, negative side of the semiconductor switching element TR ₄ to provide a bootstrap power source B which is used as the gate drive power source of the positive side of the semiconductor switching element TR ₁ to Tr _3, the power thereto between the gate drive power source S ₃ provided for to Tr _6, is provided by interposing _the switch SW 1 to cut off the power supply.

Similarly, the motor controller _{C ONT 2,} positive-side semiconductor switching elements _TR 7 and bootstrap supply B used as the gate drive power source to Tr _9, wherein the semiconductor switching element _TR 10 of the negative-side to provide a power supply to to Tr between the gate drive power source S ₃ provided in a _12, it is provided by interposing the switch SW ₂ to cut off the power supply.

During normal motor control, switch SW ₀ is turned _{off, SW} 1, SW ₂ still on, turn on the electromagnetic contactor MS, motor 1 of the respective axes by the inverter comprised of semiconductor switching elements _TR 1 _{to Tr 12} , 2 are driven.

Insulation resistance detected, stops the motor control operation of all axes, the semiconductor switching element _TR 1 _{to Tr 12} turns off to cut off the electromagnetic contactor the MS, and turns off the switch _SW 1, SW _2. Then, to measure a DC voltage _{V PN} equal inverter to the voltage of the smoothing capacitor C, the voltage of the current detection resistor _{R 1 V R1A} and the current detection resistor _{R 2} and a voltage _{V R2A.}

Since the voltage of the smoothing capacitor C is applied to the semiconductor switching element _TR 1 _{to Tr 12} constituting the inverter, a current flows through the TR ₄ from the semiconductor switching element TR _1, also, a current flows to the current detection resistor _{R 1.} Likewise current flows in TR ₁₀ from the semiconductor switching element TR _7, also, a current flows to the current detection resistor _{R 2.}

Flows from the semiconductor switching element TR ₁ to TR _4, also, the current flowing from the semiconductor switching element TR ₇ in TR ₁₀ is the leakage current of such a semiconductor switching element.

Because it turns off the switch _SW 1, _{SW 2,} the gate drive power source _{S 3} of semiconductor switching elements _TR 4 to Tr ₆ and _TR 10 _{to Tr 12} in the negative side of the bootstrap power supply B resistance _{R b,} diode _{D b} , no current flows to the current detection resistor R _1, R ₂ for insulation resistance detection through the capacitor C _b.

Then turn on the switch SW _0, the negative side bus ML _- voltage _{V DC} of the DC power source _{S 2} is applied to the ground E against the current detection resistor _{R 1} of the voltage _{V R1B} and the current detection resistor _{R 2} of the voltage Measure _VR2B .

If the motor 1 is insulation deterioration, the DC power supply voltage V _DC of S ₂ is applied to the semiconductor switching element TR ₄ of the negative-side through the insulation resistance R _m1 of the motor, the current detection resistor R ₁ and the negative side of the semiconductor switching elements current flows through the TR _4.

If there is likewise insulation deterioration in the motor 2 is a DC power supply voltage V _DC of S ₂ is applied to the semiconductor switching element TR ₁₀ on the negative side through the insulation resistance R _{m @ 2} of the motor, the current detection resistor R ₂ and the negative side semiconductor current flows to the switching element _{TR 10.}

Moreover, since the state in which the voltage _{V PN} of the smoothing capacitor C is applied to the semiconductor switching element _TR 1 _{to Tr 12,} together with the current flows to TR ₄ from the semiconductor switching element TR _1, a current in the current detection resistor _{R 1} Flows. Similarly the semiconductor switching element TR ₇ with a current flows into the _{TR 10,} current also flows to the current detection resistor _{R 2.}

Current flowing from these semiconductor switching elements TR ₁ to _{TR 10} from current and TR ₇ flows to TR ₄ is the leakage current of these semiconductor switching elements.

However, the leakage current from the semiconductor switching element TR ₁ to _{TR 10} from leakage current and TR ₇ to TR ₄ is small compared to the current flowing due to a decrease in the insulation resistance of the motor _{R m1, R m @ 2,} a smoothing capacitor C The voltage hardly drops. From these measurement results, the insulation resistances R _m1 and R _m2 of the motors 1 and 2 can be obtained from the equations (5) and (6) in the same manner as in the first embodiment of the present invention.

Although the switches SW _{1 and} SW ₂ are inserted at the positions where the three phases are simultaneously turned on / off, even if the gate drive power supply is configured so that the switches SW _{1 and} SW ₂ can be inserted into any of the phases. good.

Further, in this embodiment, the case where both the motor control devices _Cont1 and _Cont2 are the bootstrap power supply B is shown, but the motor control device _Cont2 is the bootstrap power supply B and the gate power supply of the motor control device _Cont1 is the normal power supply. also for example, if an insulating power source, only the switch SW ₁ is unnecessary, it is possible to similarly detected.

  Subsequently, as a third embodiment of the present invention, an embodiment using a high withstand voltage IC drive power supply will be described.

As shown in FIG. 3, this embodiment is one in which the present invention is applied to a case of transmitting the gate control signal of the inverter positive-side semiconductor switching elements TR ₁ to Tr ₃ and TR ₇ to Tr ₉ at high voltage IC .

During normal motor control, switch SW ₀ is turned _{off, SW} 1, SW ₂ turns on the electromagnetic contactor MS stays on, the motor 2 of each axis by inverter composed of switching elements _TR 1 _{to Tr 12} Is driven.

Insulation resistance detected, stops the motor control operation of all axes, the semiconductor switching element _TR 1 _{to Tr 12} turns off to cut off the electromagnetic contactor the MS, and turns off the switch _SW 1, SW _2. Then, the voltage _{V R1A} DC voltage _{V PN} and the current detection resistor _{R 1} equal inverter to the voltage of the smoothing capacitor C, and measuring the voltage _{V R2A} of the current detection resistor _{R 2.}

Since the voltage of the smoothing capacitor C is applied to the semiconductor switching element _TR 1 _{to Tr 12} constituting the inverter, a current flows through the TR ₄ from the semiconductor switching element TR _1, also, a current flows to the current detection resistor _{R 1.}

Likewise current flows in TR ₁₀ from the semiconductor switching element TR _7, also, a current flows to the current detection resistor _{R 2.} Current flowing from the semiconductor switching element TR ₁ to TR ₁₀ from current and TR ₇ flows to TR ₄ is a leakage current of these semiconductor switching elements.

Because it turns off the switch _SW 1, _{SW 2,} the negative side of the semiconductor switching element _TR 4 to Tr ₆ and _TR 10 the gate drive power source _{S 3} from the current for insulation resistance detecting through the power of the high voltage IC for _{to Tr 12} No current flows through the detection resistors R ₁ and R ₂ .

Then turn on the switch SW _0, the negative side bus ML _- voltage _{V DC} of the DC power source _{S 2} is applied to the ground E against the current detection resistor _{R 1} of the voltage _{V R1B} and the current detection resistor _{R 2} of the voltage Measure _VR2B .

From these measurement results, the insulation resistances R _m1 and R _m2 of the motor 1 and the motor 2 are obtained from the equations (5) and (6) as in the first and second embodiments of the present invention. Can be.

The switches SW _{1 and} SW ₂ are inserted at positions where the three phases are turned on and off at the same time. However, the gate drive power supply to the high withstand voltage IC is required so that the switches SW _{1 and} SW ₂ can be inserted into any of the phases. May be configured.

Also in the case where both the bootstrap power supply and the high-withstand voltage IC are used in combination, the switches SW1 _and SW2 are provided and the gates to both the bootstrap power supply and the high-withstand voltage IC are provided in the same manner as in the _second and third embodiments. By cutting off the connection path from the drive power supply B, the insulation resistances R _m1 and R _m2 of the motors 1 and 2 can be detected.

  As a matter of course, a gate drive power supply using a normal insulating power supply may be used in combination.

  As described above, the embodiments of the present invention have been described in detail. However, the technical scope of the present invention is not limited to what is explicitly described in the above description, but is encompassed by the matters described in the claims. All aspects are included. In addition, individual terms and descriptions are not to be construed as limiting the technical scope.

Motor 1, 2
Earth E
Insulation resistance R _m1 , R _m2
Motor control device 1 _Cont1
Motor control device 2 _Cont2
Three-phase AC power supply (first power supply) S ₁
Electromagnetic contactor (first switch) MS
Rectifier circuit (DC supply unit) S _DC
Bus ML
Positive bus ML ₊
Negative bus ML ₋
A smoothing capacitor _{(capacitor) C (C 1, C 2} )
Inverter DC voltage V _PN
Semiconductor switching element TR _{1 to} TR ₁₂
Equivalent leakage resistance R _tr1 , R _{tr2 of} semiconductor switching element
Freewheel diode D _f
Insulation resistance calculator 3 (3 ₁ , 3 ₂ )
DC power supply (second power supply) S ₂
DC power supply voltage V _DC
Switch (second switch) SW ₀
Detection control unit (current detection unit) 4 (4 ₁ , 4 ₂ )
Current detection resistors R ₁ , R ₂
Voltage of current detection resistor R1 _VR1A
Voltage _VR2A of current detection resistor R2
Gate drive power supply (third power supply) S ₃
Bootstrap power supply B
Bootstrap power supply resistance R _b
Diode D _{b of} bootstrap power supply
Bootstrap power supply capacitor C _b
Switch (third switch) SW ₁ , SW ₂
High voltage IC HVIC

Claims (9)

A first power supply unit, a first switch that can turn off power supply from the first power supply unit, a DC supply unit that outputs power from the first power supply unit to a bus, and a first power supply unit that is connected to the bus. A capacitor and a motor control device including a switching element that converts a direct current supplied to the bus into an alternating current to drive and control a motor,
A second power supply unit having one end connected to the bus and the other end grounded via a second switch;
A current detection unit that detects a current value between the winding of the motor and the bus to which the second power supply unit is connected;
The power supply is turned off by the first switch unit, and the current value detected by the current detection unit when the second switch is opened and closed, the voltage value held by the capacitor and the second power supply unit An insulation resistance calculation unit that calculates an insulation resistance value of the motor based on the generated voltage value,
The motor control device provided with. A first power supply unit that is a non-grounded DC power supply, a DC supply unit that outputs power from the first power supply unit to a bus, a capacitor connected to the bus, and a DC supplied to the bus. A motor control device provided with a switching element for driving and controlling the motor by converting the
A second power supply unit having one end connected to the bus and the other end grounded via a second switch;
A current detection unit that detects a current value between the winding of the motor and the bus to which the second power supply unit is connected;
Based on a current value detected by the current detection unit at the time of opening and closing the second switch, a voltage value held by the capacitor, and a voltage value generated by the second power supply unit, An insulation resistance calculator for calculating an insulation resistance value;
The motor control device provided with. The switching element of at least one of the motors includes a bootstrap power supply;
A third switch for turning off power supply to the bootstrap power supply when opened;
The motor control device according to claim 1, wherein the current detection unit detects a current value when the third switch is opened. The switching element of at least one of the motors includes a high-voltage IC for a gate drive that transmits a gate control signal;
A third switch for turning off power supply to the high-voltage IC when opened;
The motor control device according to claim 1, wherein the current detection unit calculates a current value of the at least one motor when the third switch is opened. The second power supply unit has one end on the negative side or the positive side connected to the bus bar, and the other end grounded,
Said voltage value generated by the second power supply unit, said is rather smaller set than the voltage value held by the capacitor, the motor control apparatus according to any one of claims 1 to 4. A first power supply unit, a first switch that can turn off power supply from the first power supply unit, a DC supply unit that outputs power from the first power supply unit to a bus, and a first power supply unit that is connected to the bus. A capacitor, and a method for detecting the insulation resistance of a motor control device including a switching element that converts a direct current supplied to the bus into an alternating current to drive and control a motor,
Turning off the power supply by the first switch,
A second power supply unit having one end connected to the bus and the other end grounded via a second switch, wherein the second switch is opened, and the bus of the motor and the second power supply are connected; And a first current value between
The second switch is closed, and a second current value between the winding of the motor and the bus to which the second power supply unit is connected is detected by the current detection unit.
An insulation resistance value of the motor is calculated based on the detected first current value and the second current value, a voltage value held by the capacitor, and a voltage value generated by the second power supply unit. ,
A method for detecting insulation resistance of a motor control device. A first power supply unit that is a non-grounded DC power supply, a DC supply unit that outputs power from the first power supply unit to a bus, a capacitor connected to the bus, and a DC supplied to the bus. A method for detecting the insulation resistance of a motor control device comprising a switching element for driving and controlling the motor by converting the
A second power supply unit having one end connected to the bus and the other end grounded via a second switch, wherein the second switch is opened, and the bus of the motor and the second power supply are connected; And a first current value between
The second switch is closed, and a second current value between the winding of the motor and the bus to which the second power supply unit is connected is detected by the current detection unit.
An insulation resistance value of the motor is calculated based on the detected first current value and the second current value, a voltage value held by the capacitor, and a voltage value generated by the second power supply unit. ,
A method for detecting insulation resistance of a motor control device. A method for detecting insulation resistance of a motor, further comprising the switching element having at least one bootstrap power supply, and having a third switch for turning off power supply to the bootstrap power supply when opened.
8. The method according to claim 6, wherein the detection of the first and second current values is performed when the third switch is opened. 9. Further, the insulation resistance of the motor includes a switching element having at least one high-voltage IC for transmitting a gate control signal and driving a gate, and a third switch for turning off power supply to the high-voltage IC when opened. A detection method,
8. The method according to claim 6, wherein the detection of the first and second current values is performed when the third switch is opened. 9.

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