TW201807425A - Motor control apparatus - Google Patents

Abstract

A motor control apparatus includes: an insulation resistance value detector that detects insulation resistance values of a plurality of motors; and a plurality of power supplies that output DC voltages, the plurality of power supplies being disposed as corresponding to the respective plurality of motors. The insulation resistance value detector, when detecting an insulation resistance value of a specific motor among the plurality of motors, applies the output voltage of the power supply corresponding to the specific motor to an earth, and applies the output voltage of another power supply to the motor corresponding to the other power supply to detect the insulation resistance value of the specific motor.

Description

Motor control

The present invention relates to a motor control device.

The servo motor is driven by a motor control device including an inverter, and is widely used in machine tools and the like. The following problems are encountered with machines that use cutting fluids, such as work machines. First, the cutting fluid adheres to the motor. Furthermore, there are cutting fluids that enter the motor and deteriorate the insulation of the motor. If the insulation deterioration of the motor progresses slowly, eventually, the motor will have a ground fault. If the motor has a ground fault, the leakage circuit breaker will trip, or the motor control device will be damaged, resulting in system shutdown. System downtime can have a significant impact on the plant's production lines. For this reason, from the viewpoint of preventive maintenance, a device capable of detecting the insulation resistance value of the motor is desired.

The problem of Japanese Patent Laid-Open No. 2015-129704 is related to the measurement accuracy of the insulation resistance value of a motor due to a leakage current flowing through a semiconductor switching element of an inverter in a conventional motor drive device. decline. In this patent publication, the following technology is disclosed (see the abstract). The motor drive device of this patent publication is characterized by having a rectifier circuit (3) for rectifying an AC voltage, a power source section (4) for smoothing a DC voltage with a capacitor (41), an inverter section (5), and current detection. A unit (7), a voltage detection unit (8), a second switch (9), and an insulation resistance value detection unit (10). The inverter unit (5) converts a DC voltage to an AC voltage via a semiconductor switching element and drives a motor. The current detection unit (7) measures a current value flowing through a resistor (71) having one end of a coil connected to the motor and the other end of one of the terminals connected to the capacitor. The voltage detection unit (8) measures the voltage value of the capacitor. The second switch (9) grounds the other terminal of the capacitor. The insulation resistance value detection unit (10) detects the insulation of the motor using two sets of current and voltage values measured in two states: the state where the second switch is turned off and the state where the second switch is turned on. resistance.

The subject of Japanese Patent Laid-Open No. 2015-169479 is to provide a motor drive device that can accurately measure the insulation resistance value of a motor without being affected by a leakage current of a semiconductor switching element at high temperatures. In this patent publication, the following technology is disclosed (see the abstract). The motor drive device of this patent publication includes a converter section, a power supply section, a plurality of inverter sections, a second switcher that connects a capacitor to the ground, and a current detection section that measures a current flowing between the capacitor and the ground. A voltage detection unit for measuring the voltage of the capacitor, and an insulation resistance value detection unit. The plurality of inverter units are connected via a branch switching element connected between the capacitor and the motor coil, and a branch switching element connected between the capacitor and the motor coil. It converts DC to AC and drives multiple motors. The insulation resistance value detection unit detects a plurality of motors by using a current value and a voltage value measured when a switching element connected to a motor coil to be measured is turned on and a switching element connected to a motor coil other than the measurement target is turned on. Insulation resistance.

The subject of Japanese Patent Laid-Open No. 2012-177695 is to detect the deterioration of the insulation resistance of the motor without using a smoothing capacitor. In this patent publication, the following technology is disclosed (see the abstract). When the smoothing capacitor is in an uncharged state, the lower branch switching element SW6 and the detection switch 32 in the inverter section 21 are connected. After this, using the low-voltage source 33 as the power generation unit, a ground G, a three-phase AC motor 4, a lower branch switching element SW6 of the inverter unit 21, a DC bus bar N on the negative side, a detection resistor 31, and Closed loop of A / D converter 34. The detection resistance 31 and the A / D converter 34 are used to detect the closed-circuit current Ic flowing in the closed circuit, so that the insulation resistance of the three-phase AC motor 4 can be detected.

In the technique of Japanese Patent Application Laid-Open No. 2015-129704, the voltage of the capacitor is used, and the voltage measured with the second switch (9) in the ON state and the second switch (9) in the OFF state is used. Two sets of current and voltage values to detect the insulation resistance of the motor. In the same document, each motor is measured in a state where the second switch (9) is ON and the second switch (9) is OFF in the case where a plurality of motors are driven. The current value and voltage value are used to determine the insulation resistance value of each motor. However, when a plurality of motors are driven, the positive side bus, the negative side bus, and the ground are common between the motors. There are the following inappropriate.

When the insulation resistance of each motor is deteriorated, the motors are electrically connected by the insulation resistance of the motors. In this case, the equivalent insulation resistance above the switching element of the first inverter driving the first motor, the insulation resistance of the first motor, the insulation resistance of the second motor, and the current detection impedance of the second motor Sequential current flow. At this time, a difference may occur between the temperature of the switching element of the first inverter driving the first motor and the temperature of the switching element of the second inverter driving the second motor. In this case, (a) the calculation result of the equivalent insulation resistance value of the switching element of the first inverter is affected by the leakage current of the switching element of the second inverter. Furthermore, (b) the calculation result of the equivalent insulation resistance value of the switching element of the second inverter is affected by the leakage current of the switching element of the first inverter. Therefore, it is difficult to accurately obtain the equivalent insulation resistance value of each switching element.

Japanese Patent Application Laid-Open No. 2015-169479 describes a case of measuring the insulation resistance value of a specific motor among a plurality of motors. In this case, it is necessary to accurately measure the insulation resistance value of the motor without being affected by the leakage current flowing through the semiconductor switching element connected to the motor other than the measurement target. Here, in the same document, based on the current and voltage values measured when the semiconductor switching element of the lower branch of the inverter connected to a motor other than the measurement target is on, the motor of the measurement target is detected. Insulation resistance value.

The current detection section in Japanese Patent Laid-Open No. 2015-169479 includes a voltage dividing resistor and a current detection resistor connected in series. The partial pressure The resistance value of the resistor is set to be large in order to suppress excessive current flow in the event of a motor ground fault. When these resistors are used to sense the current, voltage drops due to these current sensing resistors and voltage-dividing resistors occur. As a result, a potential difference occurs between the ground and the negative terminal of the capacitor. When the semiconductor switching element of the lower branch of the inverter connected to a motor other than the measurement target is turned on, if the insulation resistance value of the motor other than the measurement target decreases, the flow will be caused by the insulation resistance of the motor to be measured. The current is an insulation resistance that has decreased in the insulation resistance value of a motor other than the measurement target, and flows to the negative terminal of the capacitor. For this reason, the current flowing to the current detection resistor is reduced. Therefore, only a portion of the current flowing to a motor other than the measurement target may unfortunately detect that the insulation resistance value of the motor to be measured is higher than the original value.

The technique disclosed in Japanese Patent Laid-Open No. 2012-177695 is based on the premise that the insulation resistance of the motor is measured when the smoothing capacitor is in a non-charged state. At this time, when the voltage of the low-voltage source 33 in the same document is higher than the forward voltage drop of the flywheel diode, the smoothing capacitor is charged through the insulation resistance of the motor and the flywheel diode of the upper switching element. For this reason, it is difficult to measure accurately because the state premised on the technology of the literature is not established. Therefore, in the technology of the same document, it is necessary that the voltage of the low-voltage source 33 is very low. However, if the insulation resistance is measured at a very low voltage, a problem arises in that the measurement accuracy is low. For example, in order to accurately measure an insulation resistance value such as 100 MΩ, it is desirable to use a high voltage during measurement.

The present invention has been made to solve the above problems. One object of the present invention is to provide the following motor control device. This motor control device can measure the insulation resistance value of a specific motor among a plurality of motors, and is hardly affected by a decrease in the insulation resistance value of a motor other than the measurement target, and can accurately measure the measurement target motor. Insulation resistance.

The motor control device according to one aspect of the present invention includes, for example, a power source that applies a DC voltage to the motor, and applies a voltage from the power source to a motor that is not a detection target of the insulation resistance value. The motor of the test object is connected to the insulation resistance through the ground.

According to the homogeneous motor control device of the present invention, it is possible to suppress an influence caused by a decrease in the insulation resistance value of a motor other than the measurement target (a motor that is not a detection target of the insulation resistance value). As a result, it is possible to accurately measure the insulation resistance value of the motor to be measured (the motor to be detected as the insulation resistance value).

For example, a motor control device (this motor control device) related to one aspect of the present invention includes: detecting the absolute insulation resistance value of a plurality of motors; Edge resistance value detection section and a plurality of power sources provided with output DC voltages corresponding to each of the plurality of motors; the insulation resistance value detection section detects the insulation resistance value of a specific motor among the plurality of motors , The output voltage of the power source corresponding to the specific motor is applied to the ground, and the output voltage of the other power source is applied to the motor corresponding to the other power source; in such a case, the specific motor is detected Insulation resistance.

In this motor control device, for example, the plurality of motors include a first motor and a second motor; the insulation resistance value detection unit is configured to detect the insulation resistance values of the first motor and the second motor; The plurality of power sources include: a first power source corresponding to the first motor and a second power source corresponding to the second motor; and the motor control device further includes: switching between the first power source and the first motor The first switch in the connected state and the second switch in the connected state between the second power source and the second motor; the insulation resistance value detecting section detects the insulation resistance value of the first motor In order to apply the output voltage of the first power supply to the ground, the first switch is switched, and the second switch is switched to apply the output voltage of the second power to the second motor. In such a case, Next, the insulation resistance value of the first motor is detected. The insulation resistance value detection unit detects the insulation resistance value of the second motor in order to apply the output power of the first power source. The first switch is switched to the first motor, and the second switch is switched to apply the output voltage of the second power source to the ground. In this case, the insulation resistance of the second motor is detected. value.

The motor control device further includes, for example, a first inverter that supplies AC power to the first motor, and a second inverter that supplies AC power to the second motor; and the first inverter, which It includes: a first upper switching element and a first lower switching element connected in series with the first upper switching element; a connection point between the first upper switching element and the first lower switching element is connected to the first motor Connection; the second inverter includes: a second upper switching element and a second lower switching element connected in series with the second upper switching element; the second upper switching element and the second lower switching element The connection point is connected to the second motor. The insulation resistance value detecting unit is connected to the second upper switching element and the output terminal of the second power source when detecting the insulation resistance value of the first motor. The second lower switch is switched between the second lower switching elements, after which the output voltage of the second power source is applied to the second motor; and the insulation resistance value detecting section detects the insulation resistance of the second motor. At this time, the first switch is switched so that the output terminal of the first power source is connected between the first upper switching element and the first lower switching element, and then the output voltage of the first power source is applied to the first 1 motor.

In this motor control device, for example, the first motor and the second motor are three-phase AC motors; the connection point between the first upper switching element and the first lower switching element is connected to the first The winding connection of the phase of any one motor; the connection point between the second upper switching element and the second lower switching element is a winding connection with the phase of any one of the second motors.

In this motor control device, for example, the first power supply and The second power supply includes a high-voltage-side output terminal and a low-voltage-side output terminal. The high-voltage-side output terminal of the first power supply is connected to the first switch, and the high-voltage-side output of the second power supply. The terminal is connected to the second switch; the low-voltage-side output terminal of the first power supply is connected to the negative-side bus of the first inverter; and the low-voltage-side output terminal of the second power supply is connected to the first 2 The negative bus of the inverter is connected; the insulation resistance value detection unit detects the insulation resistance value of the first motor, the first lower switching element is ON; and the insulation resistance value detection unit detects the In the case of the insulation resistance value of the second motor, the second lower switching element is turned on.

This motor control device further includes, for example, a first current detector that measures a current flowing between the negative-side bus bar of the first inverter and the ground, and a first current detector that measures the negative side of the second inverter. The second current detector of the current flowing between the bus bar and the ground; the insulation resistance value detection unit is configured to divide the output voltage of the first power supply by the first voltage when the insulation resistance value of the first motor is detected. The current detected by the current detector is used to calculate the insulation resistance value of the first motor. The insulation resistance value detection unit is configured to divide the output voltage of the second power supply when detecting the insulation resistance value of the second motor. Based on the current detected by the second current detector, the insulation resistance value of the second motor is calculated.

In this motor control device, for example, the first power source and the second power source are each provided with a high-voltage-side output terminal and a low-voltage-side output terminal; The first switch is connected, and the low-voltage-side output terminal of the second power supply is connected to the second switch; the high-voltage-side output terminal of the first power supply is connected to the positive-side bus of the first inverter. In addition, the high-voltage-side output terminal of the second power supply is connected to the positive-side bus of the second inverter; and the insulation resistance value detecting unit detects the insulation resistance value of the first motor when the first The upper switching element is ON. When the insulation resistance value detecting unit detects the insulation resistance value of the second motor, the second upper switching element is ON.

This motor control device further includes, for example, a first current detector that measures a current flowing between the positive-side bus bar of the first inverter and the ground, and a first current detector that measures the positive side of the second inverter. The second current detector of the current flowing between the bus bar and the ground; the insulation resistance value detection unit is configured to divide the output voltage of the first power supply by the first voltage when the insulation resistance value of the first motor is detected. The current detected by the current detector is used to calculate the insulation resistance value of the first motor. The insulation resistance value detection unit is configured to divide the output voltage of the second power supply when detecting the insulation resistance value of the second motor. Based on the current detected by the second current detector, the insulation resistance value of the second motor is calculated.

The motor control device further includes, for example, a first smoothing capacitor that smoothes AC power and outputs it to the first inverter, and a second smoothing capacitor that smoothes AC power and outputs to the second inverter; The first power source outputs a voltage lower than the voltage across the first smoothing capacitor, and the second power source outputs a voltage lower than the voltage across the second smoothing capacitor. Also low voltage.

In this motor control device, for example, the insulation resistance value detection unit detects the insulation resistance value of the first motor or the second motor after charging the first smoothing capacitor and the second smoothing capacitor.

The motor control device further includes, for example, an output unit that outputs an insulation resistance value detected by the insulation resistance value detection unit.

100‧‧‧ Motor control device

110‧‧‧ smoothing capacitor

120‧‧‧ Inverter

130‧‧‧Insulation resistance value detection section

131‧‧‧ Detection Control Department

132‧‧‧Power

133‧‧‧Current Detector

134‧‧‧Switcher

FIG. 1 is a circuit diagram of a motor control device according to the first embodiment.

FIG. 2 is a circuit diagram of a motor control device according to a second embodiment.

In the following detailed description, for the purposes of explanation, numerous specific details are mentioned in order to provide a thorough understanding of the disclosed implementation. It should be understood, however, that one or more implementation aspects may be practiced without these specific details. In other different cases, well-known structures and devices are schematically shown to simplify the drawings.

<Embodiment 1: Circuit configuration of motor control device>

FIG. 1 is a circuit diagram of a motor control device according to the first embodiment of the present invention. The motor control device is a device that drives and controls a plurality of motors (the first motor 500a and the second motor 500b in FIG. 1). Implementers shown below In Formulas 1 and 2, a circuit that controls the first motor 500a is used as the motor control device 100a, and a circuit that controls the second motor 500b is used as the motor control device 100b. The constituent elements are also the same, and the component symbols are distinguished by the subscript ab. The motor control device 100a and the motor control device 100b have the same circuit configuration. For this reason, in the case of summarizing these descriptions, the subscript ab of the element symbol 100 may be omitted, and the performance of the motor control device 100 may be used. In the same way, the component symbols of other circuit structures may similarly omit the subscript ab.

Furthermore, in the first and second embodiments, the circuit for controlling the first motor 500a and the circuit for controlling the second motor 500b are conveniently and separately described, and are distinguished by the subscript ab. However, these may be configured as a single motor control device as a whole.

The motor control device 100 (100a, 100b) includes a smoothing capacitor 110 (110a, 110b), an inverter 120 (120a, 120b), and an insulation resistance value detection unit 130 (130a, 130b). The motor control device 100 receives power from the three-phase AC power source 200 through the electromagnetic contactor 300 and the rectifier circuit 400. The motor control device 100 drives and controls the motors 500 (500a, 500b) using the electric power.

The inverter 120a is an example of a first inverter that supplies AC power to the first motor 500a. The inverter 120a includes a first upper switching element (for example, three) and a first lower switching element (for example, three) connected in series with the first upper switching element. The connection point between the first upper switching element and the first lower switching element is connected to the first motor 500a (for example, a phase winding of any one of the first motor 500a).

The inverter 120b is an example of a second inverter that supplies AC power to the second motor 500b. The inverter 120b includes a second upper switching element (for example, three) and a second lower switching element (for example, three) connected in series with the second upper switching element. The connection point between the second upper switching element and the second lower switching element is connected to the second motor 500b (for example, a phase winding of any one of the second motor 500b).

The smoothing capacitor 110a smoothes the AC power and outputs it to the inverter 120a. The smoothing capacitor 110a is an example of a first smoothing capacitor. The smoothing capacitor 110b smoothes the AC power and outputs it to the inverter 120b. The smoothing capacitor 110b is an example of a second smoothing capacitor.

The rectifier circuit 400 outputs a DC voltage by full-wave rectification of a three-phase AC voltage supplied from a three-phase AC power source 200 connected through the electromagnetic contactor 300. The smoothing capacitor 110 smoothes the output of the rectifier circuit 400. The positive bus bar of the inverter 120 is connected to the positive terminal of the smoothing capacitor 110. The negative-side bus bar of the inverter 120 is connected to the negative terminal of the smoothing capacitor 110.

The insulation resistance value detection unit 130 is a functional unit that detects an impedance value of an insulation resistance provided in each motor. The insulation resistance value detection unit 130 includes a detection control unit 131 (131a, 131b), a power supply 132 (132a, 132b), a current detector 133 (133a, 133b), and a switch 134 (134a, 134b).

The insulation resistance value detection unit 130a corresponds to the first motor 500a, and is an example of the first insulation resistance value detection unit. The insulation resistance value detection unit 130b corresponds to the second motor 500b, and one of the second insulation resistance value detection units example. The detection control unit 131a corresponds to the first motor 500a, and is an example of the first detection control unit. The detection control unit 131b is an example of the second motor 500b and the second detection control unit.

The switcher 134a switches the connection state between the power source 132a and the first motor 500a. The switcher 134a is an example of the first switcher. The switcher 134b switches the connection state between the power source 132b and the second motor 500b. The switcher 134b is an example of a second switcher.

The power source 132a and the power source 132b are examples of a plurality of power sources provided to output a DC voltage corresponding to each of the plurality of motors. The power source 132a corresponds to the first motor 500a, and is an example of the first power source. The power source 132b corresponds to the second motor 500b, and is an example of the second power source.

The current detector 133a measures the current flowing between the negative-side bus bar of the inverter 120a and the ground. The current detector 133a is an example of the first current detector. The current detector 133b measures a current flowing between the negative-side bus bar of the inverter 120b and the ground. The current detector 133b is an example of a second current detector.

The power source 132 is, for example, receiving power from a three-phase AC power source 200 and outputting a DC voltage V _DC (V _DCa , V _DCb ). The DC voltage V _DC output from the power source 132 is set to a value as high as possible within a range lower than the voltage across the smoothing capacitor 110. That is, the power source 132a outputs a voltage lower than the voltage across the smoothing capacitor 110a. The power source 132b outputs a voltage lower than the voltage across the smoothing capacitor 110b.

If the power supply 132 outputs a voltage higher than the voltage across the smoothing capacitor 110, it passes through the insulation resistance 502 (impedance value R _M ) of the motor and the flywheel diode provided with the switching element on the upper side of the inverter 120. The current charged by the smoothing capacitor 110. For this reason, the detection accuracy of the insulation resistance value is reduced. The smoothing capacitor 110 may be fully charged in advance.

The high-voltage-side output terminal of the power source 132 is connected to the switch 134. The low-voltage-side output terminal of the power source 132 is connected to the negative-side bus of the inverter 120. That is, the power sources 132a and 132b are provided with a high-voltage-side output terminal and a low-voltage-side output terminal, respectively. The high-voltage-side output terminal of the power supply 132a is connected to the switch 134a. The high-voltage-side output terminal of the power supply 132b is connected to the switch 134b. The low-voltage-side output terminal of the power supply 132a is connected to the negative-side bus of the inverter 120a. The low-voltage-side output terminal of the power source 132b is connected to the negative-side bus of the inverter 120b. In the first embodiment, the voltage value of the high-voltage-side output terminal is expressed as V _DC (V _DCa , V _DCb ).

Switcher 134 switches: Is the output terminal of power supply 132 grounded to (a), and (b) is provided with an intermediate point between the upper and lower pair of switching elements corresponding to any one of inverter 120 (the upper switching element and the lower The side switching elements, that is, any one of the connection points of the upper switching element and the lower switching element) are connected. The switching procedure will be described later.

The current detector 133 is, for example, a Hall sensor or a resistor. When the current detector 133 includes a resistor, the current value can be obtained by dividing the measurement result of the voltage across the resistor by the resistance value of the resistor.

The inverter 120 receives a DC voltage from the smoothing capacitor 110, converts the DC voltage into an AC voltage of a desired frequency, and outputs the voltage to a horse. Up to 500. As a result, the inverter 120 drives and controls the motor 500. The inverter 120 includes a switching element provided for each phase of the motor 500 and a PWM (Pulse Width Modulation) control circuit (not shown). The inverter 120 controls each switching element in accordance with an ON / OFF command output from the PWM control circuit. As a result, the inverter 120 outputs a desired voltage to the motor 500.

When the motor control device 100 is operating normally, the electromagnetic contactor 300 is turned on. Next, the motor control device 100 controls the rotational position and speed of the motor 500 through the inverter 120. When the motor control device 100 detects the insulation resistance value, it temporarily stops the control operation of all the motors, and blocks the electromagnetic contactor 300 (set to be closed). In the following, the insulation resistance value of which motor is detected to distinguish the situation, and the operation of the insulation resistance value detection unit 130 will be described.

<Embodiment 1: Operation for detecting insulation resistance value: insulation resistance value of first motor 500a>

When detecting the insulation resistance value of the first motor 500a, the detection control unit 131a (insulation resistance value detection unit 130a) is connected to the ground via the switch 134a, and the three lower switching elements of the inverter 120a (the first The lower switching element) is ON. Furthermore, the detection control unit 131b (insulation resistance value detection unit 130b) connects the switcher 134b to the inverter 120b (e.g., the middle point of the switching element above or below, or the upper and lower pair) Between switching elements (the connection points of these switching elements)). Such other switching elements are OFF. After this, the output voltage V _{DCa of the} power source _{132 a is} applied to the ground. Furthermore, an output voltage V _{DCb of the} power source 132 b is applied to one of the windings of the second motor 500 _b .

The output voltage of the power source 132b is applied to only one of the windings of the second motor 500b. However, because the winding resistance value of the motor is generally very small, it can be considered that V _{DCb is} applied to any of the three-phase windings. Next, V _DCa and V _DCb are mutually equal. Therefore, as a result, no current flows in the insulation resistance 502b (impedance value R _Mb ) of the second motor 500b.

The current I _a flows through the output voltage of the power supply 132 a through the insulation resistance 502 a (impedance value R _Ma ) of the first motor 500 a and the three lower switching elements of the inverter 120 _a . The current detector 133a detects line current I _a. The detection control unit 131a (insulation resistance value detection unit 130a) is an impedance value R _Ma of the insulation resistance 502a of the first motor 500a, and can be calculated by R _Ma = V _DCa / I _a .

In this way, when detecting the insulation resistance value of the first motor 500a, the detection control unit 131a (insulation resistance value detection unit 130a) switches the switcher 134a so that the output voltage of the power source 132a is applied to the ground. Furthermore, the detection control unit 131b (insulation resistance value detection unit 130b) switches the switcher 134b in order to apply the output voltage of the power source 132b to the second motor 500b. In addition, the detection control unit 131a (insulation resistance value detection unit 130a) detects the insulation resistance value of the first motor 500a.

That is, when detecting the insulation resistance value of the first motor 500a, the detection control unit 131b (insulation resistance value detection unit 130b) is connected to the second upper switching element and the second lower switching element via the output terminal for the power source 132b. The mode of switching the switcher 134b is switched between, and the output voltage of the power source 132b is applied to the second motor 500b.

Furthermore, the detection control unit 131a (insulation resistance value detection unit 130a) detects the insulation resistance value R _{Ma of the} first motor 500a by dividing the output voltage V _DCa of the power source 132a by the current detected by the current detector 133a. As the current I _a , the insulation resistance value R _{Ma of the} first motor 500 a is calculated.

The insulation resistance value detection unit 130a sends the obtained insulation resistance value to, for example, a device held by a user. When the insulation resistance value R _Ma of the first motor 500a is low, for example, the user prevents or suppresses a system shutdown caused by a ground fault by exchanging the first motor 500a.

<Embodiment 1: Operation for detecting insulation resistance value: insulation resistance value of the second motor 500b>

When detecting the insulation resistance value of the second motor 500b, the detection control unit 131b (insulation resistance value detection unit 130b) is connected to ground via the switch 134b, and the three lower switching elements of the inverter 120b (second The lower switching element) is ON. Furthermore, the detection control unit 131a (insulation resistance value detection unit 130a) connects the switcher 134a to the inverter 120a (for example, the middle point of the switching element above or below the pair, or the pair of upper and lower pairs) Between switching elements (the connection points of these switching elements)). Such other switching elements are OFF. After this, the output voltage V _{DCb of the} power source 132 b is applied to the ground. Furthermore, the output voltage V _{DCa of the} power source _{132 a is} applied to one of the windings of the first motor _{500 a} .

The output voltage of the power supply 132a is applied to only one of the windings of the first motor 500a. However, because the winding resistance value of the motor is generally very small, it can be considered that V _{DCa is} applied to any of the three-phase windings. Next, V _DCa and V _DCb are mutually equal. Therefore, as a result, no current flows in the insulation resistance 502a (impedance value R _Ma ) of the first motor 500a.

The output voltage of the power source 132b passes through the insulation resistance 502b (impedance value R _Mb ) of the second motor 500b and the three lower switching elements of the inverter 120b, and a current I _b flows. The current detector 133b detects a current _Ib . The detection control unit 131b (insulation resistance value detection unit 130b) is an impedance value R _{Mb to} the insulation resistance 502 _b of the second motor 500 _b , and can be calculated by R _Mb = V _DCb / I _b .

In this way, when detecting the insulation resistance value of the second motor 500b, the detection control unit 131b (insulation resistance value detection unit 130b) switches the switch 134b so that the output voltage of the power source 132b is applied to the ground. Furthermore, the detection control unit 131a (insulation resistance value detection unit 130a) switches the switcher 134a so that the output voltage of the power source 132a is applied to the first motor 500a. In addition, the detection control unit 131b (insulation resistance value detection unit 130b) detects the insulation resistance value of the second motor 500b.

That is, when detecting the insulation resistance value of the second motor 500b, the detection control unit 131a (insulation resistance value detection unit 130a) is connected to the first upper switching element and the first lower switching element via the output terminal for the power source 132a. The mode of the switcher 134a is switched between, and the output voltage of the power source 132a is applied to the first motor 500a.

Furthermore, the detection control unit 131b (insulation resistance value detection unit 130b) detects the insulation resistance value R _{Mb of} the second motor 500b by dividing the output voltage V _DCb of the power supply 132b by the current detected by the current detector 133b. The insulation resistance value R _{Mb of} the second motor 500 _b is calculated based on the current I _b .

The insulation resistance value detection unit 130b sends the obtained insulation resistance value to, for example, a device held by a user. When the insulation resistance value R _Mb of the second motor 500 _b is low, for example, the user prevents or suppresses a system shutdown caused by a ground fault by exchanging the second motor 500 _b .

<Embodiment 1: Summary>

In the motor control device 100 according to the first embodiment, the detection control unit 131 (insulation resistance value detection unit 130) applies the output voltage V _{DC of the} power source 132 to a winding of a motor that is not a measurement target of the insulation resistance value. Furthermore, the detection control unit 131 (insulation resistance value detection unit 130) is a motor to be measured for the insulation resistance value, and applies the same voltage V _DC to ground. As a result, it is possible to suppress the current flowing through the insulation resistance of the motor that is not the measurement target of the insulation resistance value. Therefore, in the measurement of the insulation resistance value, it is possible to suppress an influence due to a leakage current from a switching element of an inverter driving a motor that is not the measurement target of the insulation resistance value. Moreover, when a gate power source using a charge pump as a switching element is used, the influence of a current flowing through the charge pump circuit can be suppressed.

In the motor control device 100 according to the first embodiment, after the motor 500 is operated, the electromagnetic contactor 300 may be interrupted to start the measurement of the insulation resistance value. In this case, the insulation resistance value of the motor 500 is measured in a state where the voltage across the smoothing capacitor 110 is high via the charging smoothing capacitor 110. That is, the detection control section 131a (insulation resistance value detection section 130a) can also detect the insulation resistance value of the first motor 500a after the smoothing capacitor 110a is charged. The detection control unit 131b (insulation resistance value detection unit 130b) may detect the insulation resistance value of the second motor 500b after the smoothing capacitor 110b is charged. In this case, it is possible to suppress the influence of the power source 132 on the current charged by the smoothing capacitor 110 during the measurement of the insulation resistance value. Furthermore, it is not necessary to consider the current for charging the smoothing capacitor 110, and the output voltage of the power source 132 can be increased. Therefore, the insulation resistance value of the motor 500 can be measured with high accuracy.

<Embodiment 2>

FIG. 2 is a circuit diagram of a motor control device 100 (100a, 100b) according to the second embodiment of the present invention. The motor control device 100 according to the second embodiment is different from the first embodiment in that the low-voltage-side output terminal of the power source 132 is connected to the switch 134, and the high-voltage-side output terminal of the power source 132 is connected to the positive terminal of the inverter 120. Side bus connection.

That is, in the second embodiment, the low-voltage-side output terminal of the power supply 132a is connected to the switch 134a, and the low-voltage-side output terminal of the power supply 132b is connected to the switch 134b. The high-voltage-side output terminal of the power supply 132a is connected to the positive-side bus of the inverter 120a, and the high-voltage-side output terminal of the power supply 132b is connected to the positive-side bus of the inverter 120b.

In the second embodiment, the current detector 133a measures the current flowing between the positive-side bus bar of the inverter 120a and the ground. The current detector 133a is an example of a first current detector (a third current detector). The current detector 133b measures between the busbar on the positive side of the inverter 120b and the ground Flowing current. The current detector 133b is an example of a second current detector (fourth current detector).

The other configurations are the same as those of the first embodiment. Therefore, in the following, the differences between the outputs of the power supply 132 will be mainly described.

When detecting the insulation resistance value of the first motor 500a, the detection control unit 131a (insulation resistance value detection unit 130a) is connected to ground through the switch 134a, and the three upper switching elements (the first upper side of the inverter 120a) Switching element) is ON. Furthermore, the detection control unit 131b (insulation resistance value detection unit 130b) connects the switcher 134b to the inverter 120b (for example, the middle point of the above-mentioned pair of upper and lower switching elements). Such other switching elements are OFF. As a result, the output voltage V _{DCa of the} power source _{132 a is} applied between the winding of the first motor 500 a and the ground. Furthermore, an output voltage V _{DCb of the} power source 132 b is applied to one of the windings of the second motor 500 _b . A current I _a flows through the output voltage of the power source 132 a through the three upper switching elements of the inverter 120 a and the insulation resistance 502 a (impedance value R _Ma ) of the first motor 500 _a . The subsequent operations are the same as those of the first embodiment.

When detecting the insulation resistance value of the second motor 500b, the detection control unit 131b (insulation resistance value detection unit 130b) is connected to ground through the switch 134b, and the three upper switching elements of the inverter 120b (the second upper side Switching element) is ON. Furthermore, the detection control unit 131a (insulation resistance value detection unit 130a) connects the switcher 134a to the inverter 120a (for example, the middle point of the above-mentioned pair of upper and lower switching elements). Such other switching elements are OFF. As a result, the output voltage V _{DCb of the} power source 132 b is applied between the winding of the second motor 500 b and the ground. Furthermore, the output voltage V _{DCa of the} power source _{132 a is} applied to one of the windings of the first motor _{500 a} . A current I _b flows through the output voltage of the power source 132 b through the three upper switching elements of the inverter 120 b and the insulation resistance 502 b (impedance value R _Mb ) of the second motor 500 _b . The subsequent operations are the same as those of the first embodiment.

<Related Example>

The present invention is not limited to the embodiments described above, and includes various modifications. For example, the above-mentioned embodiment is explained in detail for easy understanding of the present invention. The embodiments described above are not necessarily limited to those having all the components (configurations) described above.

In the above-mentioned embodiment, the case where the number of motors is two is explained. Even when there are three or more motors, the configuration of the present invention can be applied similarly. That is, a motor is applied from a voltage applied to a power source to an object that is not a detection target of an insulation resistance value. Furthermore, the motor (specific motor) that is the detection target of the insulation resistance value is connected to the power source and the insulation resistance through the ground. As a result, the same operation as described above can be achieved.

That is, a motor control device according to an embodiment of the present disclosure includes an insulation resistance value detection unit that detects the insulation resistance values of a plurality of motors, and a plurality of output DC voltages provided to correspond to each of the plurality of motors. Power source; the above-mentioned insulation resistance value detecting unit is configured to apply the output voltage of the power source corresponding to the specific motor to ground when detecting the insulation resistance value of the specific motor among the plurality of motors, and The output voltage is applied to the motor corresponding to the other power supply. In this case, the absolute voltage of the specific motor is detected. Edge resistance value.

In the embodiment described above, the three-phase AC power supply 200 is used. However, instead of the three-phase AC power supply 200, a single-phase AC power supply may be used. Furthermore, instead of the electromagnetic contactor 300, another AC switch may be used. As the rectifier circuit 400, a circuit such as a PWM converter that can regenerate a power source may be used. In this case, the PWM converter is also stopped when the insulation resistance value is detected. Further, instead of an AC power source, a DC power source such as a battery may be used. In this case, it is not necessary to turn off the electromagnetic contactor 300 when detecting the insulation resistance value.

The above-mentioned embodiment shows an example in which a 3-phase motor is driven by a 3-phase inverter. Even when a single-phase motor is driven by a single-phase inverter, the configuration of the present invention can be applied similarly.

The detection control unit 131 is hardware that can be used as a circuit device that realizes the functions of the detection control unit 131 and is mounted on the motor control device 100. Alternatively, it may be installed in the motor control device 100 as a processor that executes software for realizing equivalent functions.

For example, the insulation resistance value obtained by the insulation resistance value detection unit 130 may be displayed on a screen, notified to a user, or may be transmitted as data through an appropriate communication channel. Alternatively, the insulation resistance value may be output through an appropriate output terminal in the form of an electrical signal or the like indicating the insulation resistance value. The motor control device 100 may include an appropriate output unit (display unit for outputting the insulation resistance value detected by the insulation resistance value detection unit 130 in accordance with the output type of the insulation resistance value). Indicators, communication channels, and output terminals, etc.).

Alternatively, the voltage across the smoothing capacitor 110 may be in a fully charged state in advance.

The embodiments of the present disclosure may be the following first to tenth motor control devices.

The first motor control device is a motor control device for driving and controlling the first and second motors. The first motor control device includes an insulation resistance value detection unit that detects the insulation resistance of the first and second motors, and first and second output DC voltages. 2 power source, a first switcher that switches the connection between the first power source and the first motor, and a second switcher that switches the connection between the second power source and the second motor; the insulation resistance value detection unit When detecting the insulation resistance of the first motor, the first switch is switched in order to connect the output of the first power source and the ground, and the first switch is switched in order to apply the output of the second power source to the second motor. 2 In this case, the switcher detects the insulation resistance of the first motor; the insulation resistance value detecting unit is configured to apply the first power to the first motor when detecting the insulation resistance of the second motor. Output, the first switcher is switched, and the second switcher is switched to connect the output of the second power supply to the ground. In this case, the insulation voltage of the second motor is detected. .

The second motor control device is a first motor control device, and further includes: a first inverter that supplies AC power to the first motor; and a second inverter that supplies AC power to the second motor; The inverter system is configured by connecting the first upper switching element and the first lower switching element in series, and connecting such a connection point to the first motor; and the second inverter system It is configured such that the second upper switching element and the second lower switching element are connected in series, and the connection point is connected to the second motor. The insulation resistance value detecting unit detects the insulation resistance of the first motor. In order to connect the output of the second power supply between the second upper switching element and the second lower switching element to switch the second switch, the output of the second power is applied to the second motor; The insulation resistance value detecting unit is configured to switch the first first switching element in order to connect the output of the first power source between the first upper switching element and the first lower switching element when detecting the insulation resistance of the second motor. The switcher thus applies the output of the first power source to the first motor.

The third motor control device is a second motor control device, wherein the first and second motors are configured as a three-phase AC motor; a connection point between the first upper switching element and the first lower switching element. Is connected to the winding of any one of the phases of the first motor; the connection point between the second upper switching element and the second lower switching element is to any of the phases included in the second motor One phase is connected by winding.

The fourth motor control device is a second motor control device, wherein the first and second power sources are respectively provided with a high voltage side output and a low voltage side output; the high voltage side output of the first power source is the same as the first The switch is connected, and the high-voltage-side output of the second power supply is connected to the second switch; the low-voltage-side output of the first power supply is connected to the negative bus of the first inverter; and The low-voltage-side output of the second power supply is connected to the negative-side bus of the aforementioned second inverter; the aforementioned insulation resistance value The detection unit detects the insulation resistance of the first motor, and the first lower switching element is turned on. The detection unit of the insulation resistance value detects the second resistance of the second motor when the insulation resistance of the second motor is detected. The element is ON.

The fifth motor control device is a fourth motor control device, and further includes a first current detector that measures a current flowing between the negative bus and the ground of the first inverter, and a first current detector that measures the second inverter. The second current detector of the current flowing between the negative bus and the ground of the device; the insulation resistance value detecting unit is configured to divide the output voltage of the first power supply by the first current when detecting the insulation resistance of the first motor. The current detected by the detector is used to calculate the insulation resistance of the first motor. The insulation resistance value detection unit is configured to divide the output voltage of the second power supply by the first voltage when detecting the insulation resistance of the second motor. The current detected by the two current detectors is used to calculate the insulation resistance of the second motor.

The sixth motor control device is a second motor control device, wherein the first and second power sources are respectively provided with a high-voltage side output and a low-voltage side output; the low-voltage side output of the first power source is the same as the first The switch is connected, and the low-voltage side output of the second power supply is connected to the second switch; the high-voltage side output of the first power supply is connected to the positive-side bus of the first inverter; and The high-voltage-side output of the second power supply is connected to the positive-side bus of the second inverter; the insulation resistance value detecting unit detects that the first upper-side switching element is ON when detecting the insulation resistance of the first motor; The insulation resistance value detection unit is configured such that the second upper switching element is turned on when detecting the insulation resistance of the second motor.

The seventh motor control device is a sixth motor control device, and further includes a first current detector that measures a current flowing between the positive-side bus bar and the ground of the first inverter, and a first current detector that measures the second inverter. The second current detector of the current flowing between the positive bus and the ground of the device; the insulation resistance value detecting unit is configured to divide the output voltage of the first power supply by the first current when detecting the insulation resistance of the first motor. The current detected by the detector is used to calculate the insulation resistance of the first motor. The insulation resistance value detection unit is configured to divide the output voltage of the second power supply by the first voltage when detecting the insulation resistance of the second motor. The current detected by the two current detectors is used to calculate the insulation resistance of the second motor.

The eighth motor control device is a second motor control device, and further includes a first smoothing capacitor that smoothes AC power to output to the first inverter, and a smoothing AC power that outputs to the second inverter. The second smoothing capacitor; the first power source outputs a voltage smaller than the voltage across the first smoothing capacitor; the second power source outputs a voltage lower than the voltage across the second smoothing capacitor.

The ninth motor control device is an eighth motor control device, wherein the insulation resistance value detection unit detects the insulation resistance of the first and second motors after charging the first and second smoothing capacitors.

The tenth motor control device is the first motor control device, and further includes an output unit that outputs an insulation resistance value detected by the insulation resistance value detection unit.

The foregoing detailed description has been presented for the purposes of illustration and description. There are many modifications and variations that can be made according to the above teachings. It is not intended to be exhaustive or to limit the inventive subject matter described herein to the particular precise form disclosed. Although the subject matter of the invention has been described in terms of specific structural features and / or methodological acts, it should be understood that the subject matter of the invention as defined by the scope of the appended patent application is not necessarily limited to the particular feature or action described above. On the contrary, the above-mentioned specific features and behaviors are disclosed in the form of an embodiment of the scope of the patent application attached after implementation.

100a, 100b‧‧‧ Motor control device

110a, 110b‧‧‧ smoothing capacitor

120a, 120b‧‧‧ Inverter

130a‧‧‧Insulation resistance value detection section

130b‧‧‧Insulation resistance value detection section

131a‧‧‧ Detection Control Department

131b‧‧‧ Detection Control Department

132a‧‧‧ Power

132b‧‧‧ Power

133a, 133b‧‧‧Current detector

134a, 134b‧‧‧Switch

200‧‧‧Three-phase AC power

300‧‧‧ electromagnetic contactor

400‧‧‧ rectifier circuit

500a‧‧‧1st motor

500b‧‧‧ 2nd motor

502a, 502b‧‧‧ Insulation resistance

I _a , I _b ‧‧‧ flowing current

R _Ma 、 R _Mb ‧‧‧Impedance

V _Dca 、 V _DCb ‧‧‧ Output voltage

Claims (11)

A motor control device includes: an insulation resistance value detection section for detecting the insulation resistance values of a plurality of motors; and a plurality of power sources provided to output a DC voltage corresponding to each of the plurality of motors; When detecting the insulation resistance value of a specific motor among the plurality of motors, the output voltage of the power source corresponding to the specific motor is applied to ground, and the output voltage of other power sources is applied to the other motors. The power source corresponds to the aforementioned motor. In such a case, the insulation resistance value of the aforementioned particular motor is detected. For example, the motor control device according to claim 1, wherein the plurality of motors include a first motor and a second motor, and the insulation resistance value detection unit is configured to detect the insulation of the first motor and the second motor. Resistance value; the plurality of power sources include: a first power source corresponding to the first motor and a second power source corresponding to the second motor; the motor control device further includes: switching between the first power source and the first power source A first switcher for the connection state between the first motors, and a second switcher for switching the connection state between the second power supply and the second motor; the insulation resistance value detecting section detects the Insulation resistance value, in order to apply the output voltage of the first power The first switch is switched to ground and the second switch is switched to apply the output voltage of the second power source to the second motor; in such a case, the insulation resistance value of the first motor is detected; When detecting the insulation resistance value of the second motor, the insulation resistance value detecting unit switches the first switcher to apply the output voltage of the first power source to the first motor and applies the second power source. The output voltage of the second switch is switched to the ground, and in this case, the insulation resistance value of the second motor is detected. The motor control device according to claim 2, wherein the motor control device further includes a first inverter that supplies AC power to the first motor, and a second inverter that supplies AC power to the second motor. The inverter; the first inverter includes: a first upper switching element and a first lower switching element connected in series with the first upper switching element; the first upper switching element and the first lower switching element The connection point of the element is connected to the first motor; the second inverter includes: a second upper switching element and a second lower switching element connected in series with the second upper switching element; the second The connection point between the upper switching element and the second lower switching element is connected to the second motor; the insulation resistance value detecting unit detects the insulation resistance value of the first motor for the output of the second power supply. A terminal is connected between the second upper switching element and the second lower switching element to switch the second The switcher then applies the output voltage of the second power source to the second motor, and the insulation resistance value detecting unit is connected to the output terminal of the first power source when detecting the insulation resistance value of the second motor. The first switch is switched between the first upper switching element and the first lower switching element, and the output voltage of the first power source is applied to the first motor. The motor control device according to claim 3, wherein the first motor and the second motor are three-phase AC motors; the connection point between the first upper switching element and the first lower switching element, Is a winding connection to a phase of any of the first motors; the connection point between the second upper switching element and the second lower switching element is a winding to a phase of any of the second motors线 连接。 Line connection. The motor control device according to claim 3, wherein the first power source and the second power source are provided with a high voltage side output terminal and a low voltage side output terminal, respectively; the high voltage side output terminal of the first power source is connected with The first switch is connected, and the high-voltage-side output terminal of the second power supply is connected to the second switch; the low-voltage-side output terminal of the first power is connected to the first inverter. And the low-voltage-side output terminal of the second power supply is connected to the negative-side bus of the second inverter; and the insulation resistance value detecting section detects the insulation resistance value of the first motor. At this time, the first lower-side switching element is turned on; and when the insulation resistance value detecting section detects the insulation resistance value of the second motor, the second lower-side switching element is turned on. The motor control device according to claim 5, wherein the motor control device further includes a first current detector that measures a current flowing between the negative-side bus bar of the first inverter and the ground, and A second current detector for measuring a current flowing between the negative-side bus bar of the second inverter and the ground; the insulation resistance value detecting section detects the insulation resistance value of the first motor, and the first The output voltage of the power supply is divided by the current detected by the first current detector, and then the insulation resistance value of the first motor is calculated. The insulation resistance value detection unit detects the insulation resistance of the second motor. When the value is equal to the value, the output voltage of the second power source is divided by the current detected by the second current detector, and the insulation resistance value of the second motor is calculated through this. For example, the motor control device according to claim 3, wherein the first power source and the second power source each have a high-voltage side output. Output terminal and low voltage side output terminal; the low voltage side output terminal of the first power supply is connected to the first switch, and the low voltage side output terminal of the second power supply is connected to the second switch; The high-voltage-side output terminal of the first power supply is connected to the positive-side bus of the first inverter, and the high-voltage-side output terminal of the second power supply is connected to the positive-side bus of the second inverter; The insulation resistance value detection unit detects the insulation resistance value of the first motor, and the first upper switching element is ON. The insulation resistance value detection unit detects the insulation resistance value of the second motor, and the first 2 The upper switching element is ON. The motor control device according to claim 7, wherein the motor control device further includes a first current detector that measures a current flowing between the positive-side bus bar of the first inverter and the ground, and A second current detector that measures a current flowing between the positive-side bus bar of the second inverter and the ground; the insulation resistance value detecting section detects the insulation resistance value of the first motor, and the first The output voltage of the power supply is divided by the current detected by the first current detector, and then the insulation resistance value of the first motor is calculated. The insulation resistance value detection unit detects the insulation resistance of the second motor. Value, the output voltage of the second power supply divided by the second power supply The current detected by the current detector is used to calculate the insulation resistance value of the second motor. The motor control device according to claim 3, wherein the motor control device further includes a first smoothing capacitor that smoothes the AC power and outputs it to the first inverter, and smoothes the AC power and outputs the same to the foregoing. The second smoothing capacitor of the second inverter; the first power source outputs a voltage lower than the voltage across the first smoothing capacitor; the second power source outputs the voltage across the second smoothing capacitor Also low voltage. According to the motor control device of claim 9, wherein the insulation resistance value detecting unit detects the insulation of the first motor or the second motor after charging the first smoothing capacitor and the second smoothing capacitor. resistance. The motor control device according to any one of claims 1 to 10, wherein the motor control device further includes an output section that outputs an insulation resistance value detected by the insulation resistance value detection section.