PH12017000222A1

PH12017000222A1 - Motor control apparatus

Info

Publication number: PH12017000222A1
Application number: PH12017000222A
Authority: PH
Inventors: Yuji Ide; Toshio Hiraide; Keigo Kikuchi
Original assignee: Sanyo Electric Co
Priority date: 2016-08-29
Filing date: 2017-08-01
Publication date: 2018-07-23
Also published as: CN107800333A; TWI738814B; TW201807425A; JP6680648B2; JP2018038114A; CN107800333B

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

Fe) element to the first lower-side switching element is coupled to the first motor, the N second inverter includes a second upper-side switching element and a second lower-side c switching element coupled to the second upper-side switching element in series, and a ™ coupling point of the second upper-side switching element to the second lower-side = switching element is coupled to the second motor, the insulation resistance value o- detector, when detecting the insulation resistance value of the first motor, switch the e second switch to couple an output terminal of the second power supply to between the : = second upper-side switching element and the second lower-side switching element to ” apply the output voltage of the second power supply to the second motor, and the insulation resistance value detector, when detecting the insulation resistance value of the second motor, switch the first switch to couple an output terminal of the first power supply to between the first upper-side switching element and the first lower-side switching element to apply the output voltage of the first power supply to the first motor.

In this motor control apparatus, for example, the first motor and the second motor may be three-phase AC motors, the coupling point of the first upper-side switching element to the first lower-side switching element may be coupled to a winding wire of any phase of the first motor, and the coupling point of the second upper-side switching element to the second lower-side switching element may be coupled to a winding wire of any phase of the second motor.

In this motor control apparatus, for example, the first power supply and the second power supply each include 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 coupled to the first switch, and the high-voltage side output terminal of the second power supply is coupled to the second switch, the low-voltage side output terminal of a ——————————————————————————————————————————————eee ee. —. fo

CE

> [a the first power supply is coupled to a negative-side busbar of the first inverter, and the Ny low-voltage side output terminal of the second power supply is coupled to a ~ negative-side busbar of the second inverter, the insulation resistance value detector, i” when detecting the insulation resistance value of the first motor, turns on the first = lower-side switching element, and the insulation resistance value detector, when detecting the insulation resistance value of the second motor, turns on the second 2 jen] lower-side switching element. >

This motor control apparatus, for example, includes: a first current detector that measures a current that flows between the negative-side busbar of the first inverter and the earth; and a second current detector that measures a current that flows between the negative-side busbar of the second inverter and the earth, and the insulation resistance value detector, when detecting the insulation resistance value of the first motor, divides the output voltage of the first power supply by the current detected by the first current detector to calculate the insulation resistance value of the first motor, and the insulation resistance value detector, when detecting the insulation resistance value of the second motor, divides the output voltage of the second power supply by the current detected by the second current detector to calculate the insulation resistance value of the second motor. :

In this motor control apparatus, for example, the first power supply and the second power supply each include a high-voltage side output terminal and a low-voltage side output terminal, the low-voltage side output terminal of the first power supply is coupled to the first switch, and the low-voltage side output terminal of the second power supply is coupled to the second switch, the high-voltage side output terminal of the first power supply is coupled to a positive-side busbar of the first inverter, and the high-voltage side output terminal of the second power supply is coupled to a oe > ft positive-side busbar of the second inverter, the insulation resistance value detector, N when detecting the insulation resistance value of the first motor, turns on the first = upper-side switching element, and the insulation resistance value detector, when N detecting the insulation resistance value of the second motor, turns on the second = upper-side switching element. >

This motor control apparatus, for example, includes: a first current detector that 2 measures a current that flows between the positive-side busbar of the first inverter and ~ the earth; and a second current detector that measures a current that flows between the positive-side busbar of the second inverter and the earth, and the insulation resistance value detector, when detecting the insulation resistance value of the first motor, divides the output voltage of the first power supply by the current detected by the first current detector to calculate the insulation resistance value of the first motor, and the insulation resistance value detector, when detecting the insulation resistance value of the second motor, divides the output voltage of the second power supply by the current detected by the second current detector to calculate the insulation resistance value of the second motor.

In this motor control apparatus includes, for example, a first smoothing capacitor that smooths an AC power to output the AC power to the first inverter; and a second smoothing capacitor that smooths an AC power to output the AC power to the second inverter, and the first power supply outputs a voltage lower than a voltage between both ends of the first smoothing capacitor, and the second power supply outputs a voltage lower than a voltage between both ends of the second smoothing : capacitor.

In this motor control apparatus, for example, the insulation resistance value detector detects the insulation resistance value of the first motor or the second motor after the first smoothing capacitor and the second smoothing capacitor are charged. o

This motor control apparatus, for example, includes an output unit that outputs = the insulation resistance value detected by the insulation resistance value detector. h in “

BRIEF DESCRIPTION OF THE DRAWINGS m

Fig. 1 is a circuit diagram of a motor control apparatus according to a first o embodiment; and ~

Fig. 2 is a circuit diagram of a motor control apparatus according to a second embodiment.

DESCRIPTION OF THE EMBODIMENTS

In the following detailed description, for purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing.

First Embodiment; Circuit Configuration of Motor Control Apparatus

Fig. 1 is a circuit diagram of a motor control apparatus according to a first embodiment of the present invention. The motor control apparatus is an apparatus that drivingly controls a plurality of motors (a first motor 500a and a second motor 500b in

Fig. 1). In the first and second embodiments describe below, a circuit that controls the first motor 500a is a motor control apparatus 100a, and a circuit that controls the second motor 500b is a motor control apparatus 100b. Respective components are similarly distinguished using the additional characters "a" and "b" in reference numerals. The motor control apparatus 100a and the motor control apparatus 100b include identical circuit configurations. Therefore, when the motor control apparatus 100a and the o motor control apparatus 100b are described as a whole, the additional characters "a" and - "b" of the reference numeral 100 are omitted, and the expression of the motor control . apparatus 100 is possibly used. For other reference numerals of the circuit : configurations, similarly, the additional characters "a" and "b" are possibly omitted. @

In the first and second embodiments, for convenience, the circuit that controls 2 the first motor 500a and the circuit that controls the second motor 500b are separately ~ described and distinguished using the additional characters a and b. However, these circuits also can be integrally constituted as a single motor control apparatus. :

The motor control apparatuses 100 (100a arid 100b) include smoothing capacitors 110 (110a and 110b), inverters 120 (120a and 120b), and insulation resistance value detectors 130 (130a and 130b). The motor control apparatus 100 receives a supply of the electric power from a three-phase AC power supply 200 via an electromagnetic contactor 300 and a rectifier circuit 400. The motor control apparatus 100 drivingly controls motors 500 (500a and 500b) using this electric power.

The inverter 120a is an exemplary first inverter that supplies an AC power to the first motor 500a. The inverter 120a includes (for example, three) first upper-side switching elements and (for example, three) first lower-side switching elements, which are coupled to these first upper-side switching elements in series. Coupling points of the first upper-side switching elements to the first lower-side switching elements are coupled to the first motor 500a (for example, winding wires of any phases of the first motor 500a).

The inverter 120b is an exemplary second inverter that supplies an AC power to the second motor 500b. The inverter 120b includes (for example, three) second upper-side switching elements and (for example, three) second lower-side switching elements, which are coupled to these second upper-side switching elements in series. S

Coupling points of the second upper-side switching elements to the second lower-side on switching elements are coupled to the second motor 500b (for example, winding wires of any phases of the second motor 500b). IN

The smoothing capacitor 110a smooths an AC power to output the AC power o to the inverter 120a. The smoothing capacitor 110a is an exemplary first smoothing = capacitor. The smoothing capacitor 110b smooths an AC power to output the AC © power to the inverter 120b. The smoothing capacitor 110b is an exemplary second = smoothing capacitor.

The rectifier circuit 400 performs full-wave rectification of a three-phase AC voltage supplied from the three-phase AC power supply 200, which is coupled to the rectifier circuit 400 via the electromagnetic contactor 300, to output a DC voltage. The smoothing capacitor 110 smooths the output from the rectifier circuit 400. A positive-side busbar of the first inverter 120 is coupled to a positive electrode terminal of the smoothing capacitor 110. A negative-side busbar of the first inverter 120 is coupled to a negative electrode terminal of the smoothing capacitor 110.

The insulation resistance value detector 130 is a functional unit that detects insulation resistance values of insulation resistors included in the respective motors.

The insulation resistance value detectors 130 include detection controllers 131 (131a and 131b), power supplies 132 (132a and 132b), current detectors 133 (133a and 133b), and switches 134 (134a and 134b).

The insulation resistance value detector 130a, which corresponds to the first motor 500a, is an exemplary first insulation resistance value detector. The insulation resistance value detector 130b, which corresponds to the second motor 500b, is an exemplary second insulation resistance value detector, The detection controller 131a,

which corresponds to the first motor 5004, is an exemplary first detection controller. ~

The detection controller 131b, which corresponds to the second motor 500b, is an ft exemplary second detection controller.

The switch 134a switches a coupling condition between the power supply 132a and the first motor 500a. The switch 134a is an exemplary first switch. The switch 134b switches a coupling condition between the power supply 132b and the second = motor 500b. The switch 134b is an exemplary second switch. = -

The power supply 132a and the power supply 132b are exemplary plurality of = power supplies, which are disposed as corresponding to the respective plurality of motors to output the DC voltage. The power supply 132a, which corresponds to the first motor 500a, is an exemplary first power supply. The power supply 132b, which corresponds to the second motor 500b, is an exemplary second power supply.

The current detector 133a measures a current flowing between the negative-side busbar of the inverter 120a and an earth. The current detector 133a is an exemplary first current detector. The current detector 133b measures a current flowing between the negative-side busbar of the inverter 120b and an earth. The current detector 133b is an exemplary second current detector.

The power supply 132, for example, outputs DC voltages Vpc (Vpca and Voce) responding to the supply of the electric power from the three-phase AC power supply 200. The DC voltage Vpc output from the power supply 132 is set to a high value wherever possible in a range lower than a voltage between both ends of the smoothing capacitor 110. That is, the power supply 132a outputs a voltage lower than the voltage between both ends of the smoothing capacitor 110a. The power supply 132b outputs a voltage lower than the voltage between both ends of the smoothing capacitor 110b.

If the power supply 132 outputs a voltage higher than the voltage between both

- - ends of the smoothing capacitor 110, a current for charging the smoothing capacitor 110 > flows via an insulation resistor 502 (a resistance value Ry of the motor and a reflux = ! diode of the upper-side switching elements included in the inverter 120. Therefore, a ) detection accuracy of the insulation resistance value decreases. The smoothing = capacitor 110 may be preliminarily fully charged. 2

The power supply 132 has a high-voltage side output terminal coupled to the = switch 134. The power supply 132 has a low-voltage side output terminal coupled to ¥ the negative-side busbar of the inverter 120. That is, the power supplies 132a and 132b each include the high-voltage side output terminal and the low-voltage side output terminal. The high-voltage side output terminal of the power supply 132a is coupled to the switch 134a. The high-voltage side output terminal of the power supply 132b is coupled to the switch 134b. The low-voltage side output terminal of the power supply 132a is coupled to the negative-side busbar of the inverter 120a. The low-voltage side output terminal of the power supply 132b is coupled to the negative-side busbar of the inverter 120b. In this first embodiment, voltage values of the high-voltage side output terminals are expressed in Vpc (Vpca and Vey).

The switch 134 switches coupling of the output terminal of the power supply 132 to any of (a) the earth and (b) a middle point of upper and lower pair of switching elements corresponding to any one phase included in the inverter 120 (between the upper-side switching element and the lower-side switching element, that is, the coupling point of the upper-side switching element to the lower-side switching element). A switching procedure will be described later.

The current detector 133 can include, for example, a hall sensor or a resistor.

When the current detector 133 includes the resistor, a current value can be obtained such that a measurement result of a voltage between both ends of the resistor is divided

EE —————————————————————————————— area _ by a resistance value of this resistor. : ~

The inverter 120 receives the DC voltage from the smoothing capacitor 110, c and then converts this DC voltage into an AC voltage with a desired frequency to output ~ — the AC voltage to the motor 500. Thus, the inverter 120 drivingly controls the motor = 500. The inverter 120 includes switching elements, which are disposed by phases of Ny the motor 500, and a Pulse Width Modulation (PWM) control circuit (not illustrated). ©

In the inverter 120, the respective switching elements are controlled corresponding to an =

ON/OFF command output from the PWM control circuit. Thus, the inverter 120 ” outputs the desired voltage to the motor 500.

The motor control apparatus 100 turns on the electromagnetic contactor 300 in a normal operation. Then, the motor control apparatus 100 causes the inverter 120 to control a rotation position and a speed of the motor 500. When the insulation resistance value is detected, the motor control apparatus 100 once stops the control operation for all the motors to cut off (turn off) the electromagnetic contactor 300. The following separately describes operations of the insulation resistance value detector 130 according to cases where an insulation resistance value of which motor is detected.

First Embodiment: Operation that Detects Insulation Resistance Value: Insulation

Resistance Value of First Motor 500a

When the insulation resistance value of the first motor 500a is detected, the detection controller 131a (the insulation resistance value detector 130a) couples the switch 134a to the earth to turn on three lower-side switching elements (the first lower-side switching elements) of the inverter 120a. Further, the detection controller 131b (the insulation resistance value detector 130b) couples the switch 134b to the inverter 120b (for example, the above-described middle point of upper and lower pair of switching elements or between the upper and lower pair of switching elements (the

EE ——————————————————————————eeeer rere eer eee ~ coupling point of these switching elements)). Other switching elements are turned off. >

This applies the output voltage Vpc, of the power supply 132a to the earth. -

Furthermore, this applies the output voltage Vpcy of the power supply 132b to one of i” the winding wires of the second motor 500b. -

The output voltage of the power supply 132b is applied to only one of the ~ winding wires of the second motor 500b. However, since a winding-wire resistance > value of the motor is generally very small, Vpcy, can be regarded to be applied to any of ~ three-phase winding wires. Then, Vpc, and Vey are equal one another. Therefore, as the result, the current does not flow through the insulation resistor 502b (the resistance value Ry, of the second motor 500b.

The output voltage of the power supply 132a flows a current I, via an insulation resistor 502a (the resistance value Ry,) of the first motor 500a and the three lower-side switching elements of the inverter 120a. The current detector 133a detects the current I,. The detection controller 131a (the insulation resistance value detector 130a) can calculate the resistance value Ry, of the insulation resistor 502a of the first motor 500a by Ruma = Vpca/la.

Thus, when the insulation resistance value of the first motor 500a is detected, the detection controller 131a (the insulation resistance value detector 130a) switches the switch 134a so as to apply the output voltage of the power supply 132a to the earth.

Furthermore, the detection controller 131b (the insulation resistance value detector 130b) switches the switch.134b so as to apply the output voltage of the power supply 132b to the second motor. 500b. Moreover, the detection controller 131a (the insulation resistance value detector 130a) detects the insulation resistance value of the first motor 500a.

That is, when the insulation resistance value of the first motor 500a is detected,

the detection controller 131b (the insulation resistance value detector 130b) switches the > switch 134b so as to couple the output terminal of the power supply 132b to between the = second upper-side switching element and the second lower-side switching element, thus ) applying the output voltage of the power supply 132b to the second motor 500b. =

Furthermore, when the insulation resistance value Ry, of the first motor 500a iy is detected, the detection controller 131a (the insulation resistance value detector 130a) = divides the output voltage Vp, of the power supply 132a by the current I, detected by ¥ the current detector 133a, thus calculating the insulation resistance value Ry, of the first motor 500a.

The insulation resistance value detector 130a transmits the obtained insulation resistance value to, for example, an apparatus that a user has. When the insulation resistance value Ry, of the first motor 500a is low, the user, for example, exchanges the first motor 500a to prevent or restrain a system failure due to a ground fault failure.

Resistance Value of Second Motor 500b

When the insulation resistance value of the second motor 500b is detected, the detection controller 131b (the insulation resistance value detector 130b) couples the switch 134b to the earth to turn on three lower-side switching elements (the second lower-side switching elements) of the inverter 120b. Further, the detection controller 131a (the insulation resistance value detector 130a) couples the switch 134a to the inverter 120a (for example, the above-described middle point of upper and lower pair of switching elements or between the upper and lower pair of switching elements (the coupling point of these switching elements)). Other switching elements are turned off.

This applies the output voltage Vpcy, of the power supply 132b to the earth.

Furthermore, this applies the output voltage Vpc, of the power supply 132a to one of winding wires of the first motor 500a. ~

The output voltage of the power supply 132a is applied to only one of the ht winding wires of the first motor 500a. However, since the winding-wire resistance 5 value of the motor is generally very small, Vpc, is can be regarded to be applied to any ~ of three-phase winding wires. Then, since Vpc, and Vpey, are equal one another.

Therefore, as the result, the current does not flow through the insulation resistor 502a = (the resistance value Ry) of the first motor 500a. ©

The output voltage of the power supply 132b flows a current I, via an & insulation resistor 502b (the resistance value Ryp) of the second motor 500b and the three lower-side switching elements of the inverter 120b. The current detector 133b detects the current I,. The detection controller 131b (the insulation resistance value detector 130b) can calculate the resistance value Ry, of the insulation resistor 502b of the second motor 500b by Ryp = Vpep/I.

Thus, when the insulation resistance value of the second motor 500b is detected, the detection controller 131b (the insulation resistance value detector 130b) switches the switch 134b so as to apply the output voltage of the power supply 132b to the earth. Furthermore, the detection controller 131a (the insulation resistance value detector 130a) switches the switch 134a so as to apply the output voltage of the power supply 132a to the first motor 500a. Moreover, the detection controller 131b (the insulation resistance value detector 130b) detects the insulation resistance value of the : second motor S00b.

That is, when the insulation resistance value of the second motor 500b is detected, the detection controller 131a (the insulation resistance value detector 130a) switches the switch 134a so as to couple the output terminal of the power supply 132a to between the first upper-side switching element and the first lower-side switching

EE ——————_———————— = & element, thus applying the output voltage of the power supply 132a to the first motor " 500a. > bo

Furthermore, when the insulation resistance value Ry, of the second motor ™ 500b is detected, the detection controller 131b (the insulation resistance value detector = 130b) divides the output voltage Vpcy of the power supply 132b by the current I, = detected by the current detector 133b, thus calculating the insulation resistance value =

Rump of the second motor 500b. @

The insulation resistance value detector 130b transmits the obtained insulation ™ resistance value to, for example, the apparatus that the user has. When the insulation resistance value Ry, of the second motor 500b is low, the user, for example, exchanges the second motor 500b to prevent or restrain the system failure due to the ground fault failure,

First Embodiment: Summary

In the motor control apparatus 100 according to this first embodiment, the detection controller 131 (the insulation resistance value detector 130) applies the output voltage Vpc of the power supply 132 to the winding wires of the motor other than a target for measurement of the insulation resistance value. Furthermore, the detection controller 131 (the insulation resistance value detector 130) applies the identical voltage

Voc to the earth, for the motor as the target for measurement of the insulation resistance value. This can restrain the current that flows through the insulation resistor of the motor other than the target for measurement of the insulation resistance value.

Accordingly, in measurement of the insulation resistance value, this can restrain influence of the leakage current from the switching element of the inverter that drives the motor other than the target for measurement of the insulation resistance value.

When a charge pump is used as a gate power supply of the switching element, influence

- = of the current that flows via a charge pump circuit can be restrained. >

In the motor control apparatus 100 according to this first embodiment, after the = motor control apparatus 100 runs the motor 500, the measurement of the insulation ) resistance value may be started such that the electromagnetic contactor 300 is cut off. +

In this case, the insulation resistance value of the motor 500 is measured in a state 3 where the voltage between both ends of the smoothing capacitor 110 is high such that = the smoothing capacitor 110 is charged. That is, the detection controller 131a (the " insulation resistance value detector 130a) may detect the insulation resistance value of ; the first motor 500a after the smoothing capacitor 110a is charged. The detection controller 131b (the insulation resistance value detector 130b) may detect the insulation resistance value of the second motor 500b after the smoothing capacitor 110b is charged.

In this case, in measurement of the insulation resistance value, influence of the current output from the power supply 132 for charging the smoothing capacitor 110 can be restrained. It is not necessary to consider the current for charging the smoothing : capacitor 110, thus ensuring increase of the output voltage of the power supply 132.

Accordingly, the insulation resistance value of the motor 500 can be measured with high accuracy.

Second Embodiment

Fig. 2 is a circuit diagram of motor control apparatuses 100 (100a and 100b) according to the second embodiment of the present invention. In the motor control apparatus 100 according to the second embodiment, unlike the first embodiment, the power supply 132 has the low-voltage side output terminal coupled to the switch 134, and the power supply 132 has the high-voltage side output terminal coupled to the positive-side busbar of the inverter 120.

That is, in the second embodiment, the low-voltage side output terminal of the

> power supply 132a is coupled to the switch 134a, and the low-voltage side output < terminal of the power supply 132b is coupled to the switch 134b. The high-voltage © side output terminal of the power supply 132a is coupled to the positive-side busbar of the inverter 120a, and the high-voltage side output terminal of the power supply 132b is = coupled to the positive-side busbar of the inverter 120b. 2

In the second embodiment, the current detector 133a measures a current = flowing between the positive-side busbar of the inverter 120a and the earth. The > current detector 133a is an exemplary first current detector (a third current detector).

The current detector 133b measures a current flowing between the positive-side busbar of the inverter 120b and the earth. The current detector 133b is an exemplary second current detector (a fourth current detector).

Other configurations are similar to those in the first embodiment. Therefore, the following mainly describes a difference regarding the output of the power supply 132.

When the insulation resistance value of the first motor 500a is detected, the detection controller 131a (the insulation resistance value detector 130a) couples the switch 134a to the earth to turn on the three upper-side switching elements (the first upper-side switching elements) of the inverter 120a. Further, the detection controller 131b (the insulation resistance value detector 130b) couples the switch 134b to the inverter 120b (for example, the above-described middle point of upper and lower pair of switching elements). Other switching elements are turned off. This applies the output voltage Vpc, of the power supply 132a to between the winding wires of the first motor 500a and the earth. Furthermore, this applies the output voltage Vpcy of the power supply 132b to one of the winding wires of the second motor 500b. The output voltage of the power supply 132a flows the current I, via the three upper-side switching

EEE ———e———————————eee o elements of the inverter 120a and the insulation resistor 502a (the resistance value Rua) — of the first motor 500a. Subsequent operations are similar to those in the first - embodiment. —

When the insulation resistance value of the second motor 500b is detected, the - detection controller 131b (the insulation resistance value detector 130b) couples the ~ switch 134b to the earth to turn on the three upper-side switching elements (the second & upper-side switching elements) of the inverter 120b. Further, the detection controller @ 131a (the insulation resistance value detector 130a) couples the switch 134a to the inverter 120a (for example, the above-described middle point of upper and lower pair of switching elements). Other switching elements are turned off. This applies the output voltage Vpcy of the power supply 132b to between the winding wires of the second motor 500b and the earth. Furthermore, this applies the output voltage Vpca of the power supply 132a to one of the winding wires of the first motor 500a. The output voltage of the power supply 132b flows the current I, via the three upper-side switching elements of the inverter 120b and the insulation resistor 502b (the resistance value Rup) of the second motor 500b. Subsequent operations are similar to those in the first embodiment.

Modification -

The present invention is not limited to the above-described embodiment and includes various modifications. For example, the above-described embodiment is described in detail in order to describe the present invention comprehensibly. The above-described embodiment is not necessarily limited to include all the described : members (configurations).

In the above-described embodiments, the case where there are two motors has been described. Similarly, the configuration of the present invention is also applicable

EE ———— EE — to a case Where there are three or more motors. That is, the voltage is applied from the v2 power supply to the motor other than the target for detection of the insulation resistance ~ value. Furthermore, for the motor as the target for detection of the insulation resistance value (a specific motor), the insulation resistor is coupled to the power supply . viatheearth. This ensures the operations similar to the above. .

That is, the motor control apparatus according to one embodiment of this 5 disclosure 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, and 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.

In the above-described embodiment, the three-phase AC power supply 200 is used. However, a single-phase AC power supply may be used instead of the three-phase AC power supply 200. Furthermore, another AC switch may be used instead of the electromagnetic contactor 300. A circuit that can regenerate with respect to a power supply, such as a PWM converter may be used as the rectifier circuit 400.

In this case, the PWM converter is also stopped when detecting the insulation resistance value. A DC power supply such as a battery may be used instead of the AC power supply. In this case, it is not necessary to turn off the electromagnetic contactor 300 when detecting the insulation resistance value.

The above-described embodiment has indicated an example where a

HE EE EE EEE ———————————————————————————— ee eee |__ =

Ci three-phase inverter drives a three-phase motor. Similarly, the configuration of the = present invention is also applicable to a case where a single-phase inverter drives a 2 single-phase motor. )

The detection controller 131 can be implemented into the motor control = apparatus 100, as hardware such as a circuit device that ensures the function of the 2 detection controller 131. Alternatively, the detection controller 131 can be 2 implemented into the motor control apparatus 100, as a processor that executes software o for ensuring the function identical to that of the detection controller 131.

The insulation resistance value derived by the insulation resistance value detector 130, for example, can be displayed on a screen to be notified to the user, and can be transmitted as data via an appropriate communication path. Alternatively, the insulation resistance value can be output in a form such as an electrical signal representing the insulation resistance value via an appropriate output terminal. The motor control apparatus 100 can include appropriate output units (a display, a communication path, an output terminal, and the like) in order to output the insulation resistance value detected by the insulation resistance value detector 130 corresponding to an output form of the insulation resistance value.

The voltage between both ends of the smoothing capacitor 110 may be set into the state preliminarily fully charged.

The embodiments of this disclosure may be the following first to tenth motor control apparatuses.

The first motor control apparatus is a motor control apparatus that drivingly controls first and second motors, the motor control apparatus including an insulation resistance value detector that detects insulation resistances of the first and second motors, first and second power supplies that output DC voltages, a first switch that on - switches a connection between the first power supply and the first motor, a second > switch that switches a connection between the second power supply and the second “ motor, and the insulation resistance value detector, when detecting the insulation ) resistance of the first motor, switches the first switch to couple the output of the first +» power supply to an earth, and switches the second switch to apply the output of the 3 second power supply to the second motor to detect the insulation resistance of the first = motor, and the insulation resistance value detector, when detecting the insulation o a) resistance of the second motor, switches the first switch to apply the output of the first power supply to the first motor, and switches the second switch to couple the output of the second power supply to an earth to detect the insulation resistance of the second motor,

The second motor control apparatus, which is the first motor control apparatus, further including a first inverter that supplies an AC power to the first motor, and a second inverter that supplies an AC power to the second motor, and the first inverter is configured such that a first upper-side switching element is coupled to a first lower-side switching element in series, and a coupling point of the first upper-side switching element to the first lower-side switching element is coupled to the first motor, the second inverter is configured such that a second upper-side switching element is coupled to a second lower-side switching element in series, and a coupling point of the second upper-side switching element to the second lower-side switching element is coupled to the second motor, the insulation resistance value detector, when detecting the insulation resistance of the first motor, switch the second switch to couple the output of the second power supply to between the second upper-side switching element and the second lower-side switching element to apply the output of the second power supply to the second motor, and the insulation resistance value detector, when detecting the insulation resistance of the second motor, switch the first switch to couple the output of " the first power supply to between the first upper-side switching element and the first S lower-side switching element to apply the output of the first power supply to the first ™ motor. =

The third motor control apparatus is the second motor control apparatus, and ol the first and second motors are configured as three-phase AC motors, the coupling point = of the first upper-side switching element to the first lower-side switching element is = coupled toa winding wire of any phase included in the first motor, and the coupling = point of the second upper-side switching element to the second lower-side switching element is coupled to a winding wire of any phase included in the second motor.

The fourth motor control apparatus is the second motor control apparatus, and the first and second power supplies each include a high-voltage side output and a low-voltage side output, the high-voltage side output of the first power supply is coupled to the first switch, and the high-voltage side output of the second power supply is coupled to the second switch, the low-voltage side output of the first power supply is coupled to a negative-side busbar of the first inverter, and the low-voltage side output of the second power supply is coupled to a negative-side busbar of the second inverter, the insulation resistance value detector, when detecting the insulation resistance of the first motor, turns on the first lower-side switching element, and the insulation resistance value detector, when detecting the insulation resistance of the second motor, turns on the second lower-side switching element.

The fifth motor control apparatus is the fourth motor control apparatus further including a first current detector that measures a current that flows between the negative-side busbar of the first inverter and the earth, and a second current detector that measures a current that flows between the negative-side busbar of the second inverter

MOTOR CONTROL APPARATUS "

BACKGROUND ~ 1. Technical Field -

The present invention relates to a motor control apparatus, - 2. Description of the Related Art =

A servomotor, which is driven by a motor control apparatus including an “ inverter, is used for a machine tool or the like. A machine that performs processing using a cutting fluid, such as the machine tool, has the following problems. First, the cutting fluid attaches a motor. Furthermore, some cutting fluids get into an inside of the motor to deteriorate an insulation of the motor. If the insulation of the motor gradually deteriorates, a ground fault of the motor occurs finally. The ground fault of the motor trips an earth leakage circuit breaker or breaks the motor control apparatus to generate a system failure. The system failure considerably affects a manufacturing line of a plant. Therefore, an apparatus that can detect an insulation resistance value of the motor is preferred from the aspect of preventive maintenance.

JP-A-2015-129704 has a problem that in a conventional motor drive device, the measurement accuracy of an insulation resistance value of a motor deteriorates due to aleakage current flowing via a semiconductor switching element of an inverter.

This patent publication discloses the following technique (see abstract). A motor drive device of this patent publication includes a rectification circuit (3) that rectifies an AC voltage, a power source unit (4) that smooths a DC voltage by a capacitor (41), an inverter unit (5), a current detection unit (7), a voltage detection unit (8), a second switch (9), and an insulation resistance detection unit (10). The inverter unit (5)

= oo and the earth, and the insulation resistance value detector, when detecting the insulation or resistance of the first motor, divides the output voltage of the first power supply by the ~ current detected by the first current detector to calculate the insulation resistance of the ~ first motor, and the insulation resistance value detector, when detecting the insulation =v . Ll resistance of the second motor, divides the output voltage of the second power supply ~~ by the current detected by the second current detector to calculate the insulation & resistance of the second motor. w

The sixth motor control apparatus is the second motor control apparatus, and the first and second power supplies each include a high-voltage side output and a low-voltage side output, the low-voltage side output of the first power supply is coupled to the first switch, and the low-voltage side output of the second power supply is coupled to the second switch, the high-voltage side output of the first power supply is coupled to a positive-side busbar of the first inverter, and the high-voltage side output of the second power supply is coupled to a positive-side busbar of the second inverter, the insulation resistance value detector, when detecting the insulation resistance of the first motor, turns on the first upper-side switching element, and the insulation resistance value detector, when detecting the insulation resistance of the second motor, turns on the second upper-side switching element.

The seventh motor control apparatus is the sixth motor control apparatus further including a first current detector that measures a current that flows between the positive-side busbar of the first inverter and the earth, and a second current detector that measures a current that flows between the positive-side busbar of the second inverter and the earth, and the insulation resistance value detector, when detecting the insulation resistance of the first motor, divides the output voltage of the first power supply by the current detected by the first current detector to calculate the insulation resistance of the

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Pot i first motor, and the insulation resistance value detector, when detecting the insulation > resistance of the second motor, divides the output voltage of the second power supply = by the current detected by the second current detector to calculate the insulation ) resistance of the second motor. =

The eighth motor control apparatus is the second motor control apparatus ~ further including a first smoothing capacitor that smooths an AC power to output the o

AC power to the first inverter, and a second smoothing capacitor that smooths an AC © power to output the AC power to the second inverter, and the first power supply outputs a voltage smaller than a voltage between both ends of the first smoothing capacitor, and the second power supply outputs a voltage smaller than a voltage between both ends of the second smoothing capacitor.

The ninth motor control apparatus is the eighth motor control apparatus, and the insulation resistance value detector charges the first and second smoothing capacitors, and then detects the insulation resistances of the first and second motors.

The tenth motor control apparatus is the first motor control apparatus further including an output unit that outputs a value of the insulation resistance detected by the insulation resistance value detector.

The foregoing detailed description has been presented for the purposes of illustration and description. Many modifications and variations are possible in light of the above teaching. It is not intended to be exhaustive or to limit the subject matter described herein to the precise form disclosed. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims oo

I~ ~ . lea] no appended hereto. "

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> converts the DC voltage into an AC voltage by a semiconductor switching element so as ~ to drive a motor. The current detection unit (7) measures the value of current flowing & through a resistor (71) whose one end is connected to a coil of the motor and whose ~ another end is connected to one terminal of the capacitor. The voltage detection unit = 5S (8) measures a voltage value of the capacitor. The second switch (9) grounds the other - terminal of the capacitor. The insulation resistance detection unit (10) detects an © insulation resistance value of the motor by using two pairs of current values and voltage © values which are measured in two states where the second switch is turned off and “ where the second switch is turned on,

JP-A-2015-169479 has an object to provide a motor driving apparatus that ensures accurate measurement of an insulation resistance value of a motor without being influenced by a leakage current of a semiconductor switching element, even in high temperature. This patent publication discloses the following technique (see abstract).

A motor driving apparatus of this patent publication includes a converter unit, a power supply, a plurality of inverter units, a second switch, which couples the capacitor to the ground, a current detector, which measures a current flowing between the capacitor and the ground, a voltage detector, which measures a voltage of the capacitor, and an insulation resistance value detector. The plurality of inverter units each convert a DC current into an AC by an upper arm switching element, which is coupled to between a capacitor and a motor coil, and a lower arm switching element, which is coupled to between the capacitor and a motor coil to drive a plurality of motors. The insulation resistance value detector uses a current value and a voltage value, which have been measured in a state where a switching element to which a measurement-target motor coil is coupled is turned on, and a switching element to which a non-measurement-target motor coil is coupled is turned on, to detect the insulation resistance values of the

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JP-A-2012-177695 has an object to detect deterioration of insulation resistor of = a motor without using a smoothing capacitor. This patent publication discloses the ~ ~~ following technique (see abstract). When a smoothing capacitor is in a non-charged = state, a lower arm switching element SW6 in an inverter 21 is coupled to a detection > switch 32. This can form a closed circuit with a low voltage source 33 as an o electromotive unit and including the ground G, a three-phase AC motor 4, the lower arm = switching element SW6 of the inverter 21, a negative side DC bus N, a detection - resistor 31, and an A/D converter 34. By detecting a closed circuit current Ic flowing in the closed circuit with the detection resistor 31 and the A/D converter 34, the deterioration of the insulation resistor of the three-phase AC motor 4 can be detected.

The technique in JP-A-2015-129704 detects the insulation resistance value of the motor by two pairs of current values and voltage values measured in each of the ON state of the second switch (9) and the OFF state of the second switch (9), using the voltage of the capacitor. In this literature, even when a plurality of motors are driven, similarly, insulation resistance values of the respective motors are obtained by concurrently measuring the current values and the voltage values in each of the ON state of the second switch (9) and the OFF state of the second switch (9) for the respective motors. However, when the plurality of motors are driven, since a positive-side busbar, anegative-side busbar, and an earth are common in the motors, there is the following inconvenience.

When each of insulation resistors of the respective motors is deteriorated, the motors are electrically coupled to one another through the insulation resistors of the motors. In this case, the current flows in this order: an upper-side equivalent insulation resistor of a switching element of a first inverter that drives a first motor, an insulation

- resistor of the first motor, an insulation resistor of a second motor, and a current > detecting resistor at a side of the second motor. At this time, there is sometimes a = difference between a temperature of the switching element of the first inverter that ~ drives the first motor and a temperature of a switching element of the second inverter nN that drives the second motor. In this case, (a) a calculation result of an equivalent o insulation resistance value of the switching element of the first inverter is affected by i the leakage current of the switching element of the second inverter. Further, (b) a > calculation result of an equivalent insulation resistance value of the switching element = of the second inverter is affected by the leakage current of the switching element of the firstinverter. Accordingly, it is difficult to accurately obtain the equivalent insulation resistance values of the respective switching elements.

JP-A-2015-169479 discloses a case where the insulation resistance value of a specific motor among the plurality of motors is measured. In this case, it is necessary to measure the insulation resistance value of the motor accurately without being influenced by the leakage current, which flows via the semiconductor switching element where the non-measurement-target motor is coupled. Accordingly, in this document, the insulation resistance value of the measurement-target motor is detected based on a current value and a voltage value, which have been measured in a state where the lower arm semiconductor switching element of the inverter where the non-measurement-target motor is coupled is on.

The current detector in JP-A-2015-169479 includes a voltage dividing resistor and a current detecting resistor, which are coupled each other in series. A resistance value of this voltage dividing resistor is set large in order to restrain an excessive current from flowing in case of the ground fault of the motor. When detecting a current using these resistors, a voltage drop due to these current detecting resistor and

© 03 voltage dividing resistor occurs. As a result, an electric potential difference occurs ~ between the ground and a negative electrode side terminal of the capacitor. In the case 5 where the lower arm semiconductor switching element of the inverter where the ~ non-measurement-target motor is coupled is on, if the insulation resistance value of the iN non-measurement-target motor has been decreased, a current flowing through an - insulation resistor of the measurement-target motor flows to the negative electrode side = terminal of the capacitor through an insulation resistor where the insulation resistance ° value has been decreased of the non-measurement-target motor. This reduces a current ~ flowing to the current detecting resistor. Accordingly, the insulation resistance value of the measurement-target motor may be detected higher than a true insulation resistance value by the current flowing to the non-measurement-target motor.

The technique in JP-A-2012-177695 is based on the premise that the insulation resistance value of the motor is measured when the smoothing capacitor is in the non-charged state. At this time, when the voltage of the low voltage source 33 in this literature is higher than a forward voltage drop of a reflux diode, the smoothing capacitor is charged via the insulation resistor of the motor and a reflux diode of an upper-side switching element. Therefore, the premised state of the technique of this literature is not satisfied. Thus, the accurate measure is difficult. Accordingly, in the technique of this literature, it is necessary that the voltage of the low voltage source 33 isverylow. However, the measurement of the insulation resistance value under the very low voltage causes a problem that a measurement accuracy is low. For example, in order to accurately measure a high insulation resistance value, for example, 100 MQ, it is preferred that the voltage used in measurement is higher. | SUMMARY

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The present invention has been made in order to solve the above-described — problem. One object of the present invention is to provide the following motor control - apparatus. This motor control apparatus ensures an accurate measurement of the La insulation resistance value of the measurement-target motor almost without being =z wo influenced by the decrease of the insulation resistance value of the & non-measurement-target motor, even when measuring the insulation resistance value of 5 a specific motor among the plurality of motors. -

The motor control apparatus according to one aspect of the present invention, for example, includes a power supply that applies a DC voltage to a motor, applies the voltage from the power supply to a motor other than the target for detection of the insulation resistance value, and for a motor as the target for detection of the insulation resistance value, couples an insulation resistor to the power supply via an earth.

The motor control apparatus according to one aspect of the present invention ensures restraining influence by the insulation resistance value of the non-measurement-target motor (the motor other than the target for detection of the insulation resistance value) being decreased. As a result, it is possible to accurately measure the insulation resistance value of the measurement-target motor (the motor as the target for detection of the insulation resistance value).

For example, a motor control apparatus according to an aspect of the present invention (this 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

Le 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. ~

In this motor control apparatus, for example, the plurality of motors include a = first motor and a second motor, the insulation resistance value detector is configured to o- detect insulation resistance values of the first motor and the second motor, the plurality o © of power supplies include a first power supply corresponding to the first motor and a = second power supply corresponding to the second motor, this motor control apparatus = further includes a first switch that switches a coupling condition between the first power supply and the first motor and a second switch that switches a coupling condition between the second power supply and the second motor, the insulation resistance value detector, when detecting the insulation resistance value of the first motor, switches the first switch to apply the output voltage of the first power supply to the earth, and switches the second switch to apply the output voltage of the second power supply to the second motor to detect the insulation resistance value of the first motor, and the insulation resistance value detector, when detecting the insulation resistance value of the second motor, switches the first switch to apply the output voltage of the first power supply to the first motor, and switches the second switch to apply the output voltage of the second power supply to the earth to detect the insulation resistance value of the second motor.

This motor control apparatus, for example, further includes: a first inverter that supplies an AC power to the first motor; and a second inverter that supplies an AC power to the second motor. The first inverter includes a first upper-side switching element and a first lower-side switching element coupled to the first upper-side switching element in series, and a coupling point of the first upper-side switching

Claims

@ be CLAIMS: ~

1. A motor control apparatus comprising: = 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, wherein 2 the insulation resistance value detector, when detecting an insulation resistance o a 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. 2, The motor control apparatus according to claim 1, wherein: the plurality of motors include a first motor and a second motor, the insulation resistance value detector is configured to detect insulation resistance values of the first motor and the second motor, the plurality of power supplies include a first power supply corresponding to the first motor and a second power supply corresponding to the second motor, the motor control apparatus further includes a first switch that switches a coupling condition between the first power supply and the first motor and a second switch that switches a coupling condition between the second power supply and the second motor, the insulation resistance value detector, when detecting the insulation resistance value of the first motor, switches the first switch to apply the output voltage of the first power supply to the earth, and switches the second switch to apply the output

& & voltage of the second power supply to the second motor to detect the insulation "~ resistance value of the first motor, and c the insulation resistance value detector, when detecting the insulation ~ resistance value of the second motor, switches the first switch to apply the output = voltage of the first power supply to the first motor, and switches the second switch to o apply the output voltage of the second power supply to the earth to detect the insulation © resistance value of the second motor. = Ww

3. The motor control apparatus according to claim 2, the motor control apparatus further comprising: a first inverter that supplies an AC power to the first motor; and a second inverter that supplies an AC power to the second motor, wherein: the first inverter includes a first upper-side switching element and a first lower-side switching element coupled to the first upper-side switching element in series, and a coupling point of the first upper-side switching element to the first lower-side switching element is coupled to the first motor, the second inverter includes a second upper-side switching element and a second lower-side switching element coupled to the second upper-side switching element in series, and a coupling point of the second upper-side switching element to the second lower-side switching element is coupled to the second motor, the insulation resistance value detector, when detecting the insulation resistance value of the first motor, switch the second switch to couple an output terminal of the second power supply to between the second upper-side switching element and the second lower-side switching element to apply the output voltage of the second power supply to the second motor, and the insulation resistance value detector, when detecting the insulation ~ resistance value of the second motor, switch the first switch to couple an output terminal & of the first power supply to between the first upper-side switching element and the first ~ lower-side switching element to apply the output voltage of the first power supply to the = first motor. -

4, The motor control apparatus according to claim 3, wherein: < the first motor and the second motor are three-phase AC motors, = the coupling point of the first upper-side switching element to the first lower-side switching element is coupled to a winding wire of any phase of the first motor, and the coupling point of the second upper-side switching element to the second lower-side switching element is coupled to a winding wire of any phase of the second motor,

5. The motor control apparatus according to claim 3, wherein: the first power supply and the second power supply each include 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 coupled to the first switch, and the high-voltage side output terminal of the second power supply is coupled to the second switch, the low-voltage side output terminal of the first power supply is coupled to a : negative-side busbar of the first inverter, and the low-voltage side output terminal of the second power supply is coupled to a negative-side busbar of the second inverter, the insulation resistance value detector, when detecting the insulation resistance value of the first motor, turns on the first lower-side switching element, and "~ the insulation resistance value detector, when detecting the insulation > ht resistance value of the second motor, turns on the second lower-side switching element. md -

&

6. The motor control apparatus according to claim 5, the motor control apparatus o further comprising: © a first current detector that measures a current that flows between the @ negative-side busbar of the first inverter and the earth; and ~ a second current detector that measures a current that flows between the negative-side busbar of the second inverter and the earth, wherein: the insulation resistance value detector, when detecting the insulation resistance value of the first motor, divides the output voltage of the first power supply by the current detected by the first current detector to calculate the insulation resistance value of the first motor, and the insulation resistance value detector, when detecting the insulation resistance value of the second motor, divides the output voltage of the second power supply by the current detected by the second current detector to calculate the insulation resistance value of the second motor.

7. The motor control apparatus according to claim 3, wherein: the first power supply and the second power supply each include a high-voltage side output terminal and a low-voltage side output terminal, the low-voltage side output terminal of the first power supply is coupled to the first switch, and the low-voltage side output terminal of the second power supply is coupled to the second switch,

: the high-voltage side output terminal of the first power supply is coupled to a " positive-side busbar of the first inverter, and the high-voltage side output terminal of the 5 second power supply is coupled to a positive-side busbar of the second inverter, ~ the insulation resistance value detector, when detecting the insulation = resistance value of the first motor, turns on the first upper-side switching element, and - the insulation resistance value detector, when detecting the insulation oO = resistance value of the second motor, turns on the second upper-side switching element. 2 ho

8. The motor control apparatus according to claim 7, the motor control apparatus further comprising: a first current detector that measures a current that flows between the positive-side busbar of the first inverter and the earth; and a second current detector that measures a current that flows between the positive-side busbar of the second inverter and the earth, wherein: the insulation resistance value detector, when detecting the insulation resistance value of the first motor, divides the output voltage of the first power supply by the current detected by the first current detector to calculate the insulation resistance value of the first motor, and the insulation resistance value detector, when detecting the insulation resistance value of the second motor, divides the output voltage of the second power supply by the current detected by the second current detector to calculate the insulation resistance value of the second motor.

9. The motor control apparatus according to claim 3, the motor control apparatus further comprising:

o a first smoothing capacitor that smooths an AC power to output the AC power ~ to the first inverter; and c a second smoothing capacitor that smooths an AC power to output the AC ~ power to the second inverter, wherein: > 5 the first power supply outputs a voltage lower than a voltage between both pod ends of the first smoothing capacitor, and @ the second power supply outputs a voltage lower than a voltage between both © ends of the second smoothing capacitor. *

10. The motor control apparatus according to claim 9, wherein the insulation resistance value detector detects the insulation resistance value of the first motor or the second motor after the first smoothing capacitor and the second smoothing capacitor are charged.

11. The motor control apparatus according to any one of claims 1 to 10, the motor control apparatus further comprising an output unit that outputs the insulation resistance value detected by the insulation resistance value detector.