TW202107107A - Motor control apparatus and insulation resistance detection method for same - Google Patents

Abstract

Provided is a motor control apparatus which includes: a first power supply unit; a first switch which is able to cut off supply of power from the first power supply unit; a direct current supply unit configured to output power from the first power supply unit to a bus; a capacitor connected to the bus; and a switching element configured to convert direct current supplied to the bus to alternating current and control drive of a motor. The motor control apparatus includes: a second power supply unit connected at one end to the bus and grounded at the other end via a second switch; a current detection unit configured to detect a value of a current between a winding of the motor and the bus connected to the second power supply unit; and an insulation resistance calculation unit, configured to, after cutting off the supply of power by the first switch unit, calculate an insulation resistance value of the motor on the basis of current values detected by the current detection unit in open and closed states of the second switch, a voltage value of the capacitor, and a voltage value of the second power supply unit.

Description

Motor control device and its insulation resistance detection method

The present invention relates to a motor control device equipped with a motor's insulation resistance detection function, and an insulation resistance detection method of the motor control device.

Motors such as servo motors driven by motor control devices containing inverters are widely used in machine tools and the like. When using these machine tools for processing operations, cutting fluids are used. For this reason, because of the cutting fluid, the cutting fluid adhering to the motor enters the inside of the motor, causing a problem of deteriorating the insulation of the motor.

In addition, the same problem occurs when it is used other than machine tools, when a motor such as a servo motor is used for a long period of time, or because of the environment in which it is used.

The insulation deterioration of the motor progresses slowly, eventually causing a ground fault. The ground fault of the motor causes the leakage circuit breaker to trip, or damages the motor control device, causing the system to stop. System downtime will have a significant impact on the factory's production line. For this reason, from the viewpoint of preventive maintenance, it is desirable to have a device that can detect the insulation resistance of the motor.

As a document that discloses a method for detecting the insulation resistance of a motor, there is Japanese Patent No. 4961045. In Japanese Patent No. 4961045, a motor drive device is described, which is connected to a positive side DC bus and a negative side DC bus in a DC power source; it is characterized by having: a motor drive unit with an inverter unit Furthermore, the inverter unit converts DC power into AC power to drive the AC motor. The inverter unit has an arm switching element that switches the connection and interruption of the AC motor; a low-voltage source, which is set in the positive Between either one of the negative side DC bus or the negative side DC bus and the ground; the current detection unit detects that when connected to any one of the selected arm switching elements, the current flow includes a low-voltage source, an AC motor, and an inverter. The closed loop current of a part of the closed loop of the converter part, and the bias current that flows in the closed loop when all the arm switching elements are interrupted; The difference between the value of the loop current and the value of the bias current; and the insulation resistance deterioration determination unit, which determines the insulation resistance of the AC motor by comparing the difference based on the value of the closed loop current with a predetermined threshold Degrade.

Furthermore, Japanese Patent Laid-Open No. 2015-129704 describes a motor drive device including: a rectifier circuit that rectifies an AC voltage supplied from an AC power source through a first switch to a DC voltage; and a power supply unit, which is A capacitor is used to smooth the DC voltage rectified by the rectifier circuit; the inverter section converts the DC voltage smoothed by the power supply section into an AC voltage through the switching action of a semiconductor switching element to drive the motor ; Current detection part, which measures the current value flowing in the resistor having one end of the coil connected to the motor and the other end connected to one of the terminals of the capacitor; Voltage detection part, which measures the voltage value across the capacitor ; The second switch, which connects the other terminal of the capacitor to ground; and the insulation resistance detection part, which stops the operation of the motor and disconnects the first switch. Furthermore, when the second switch is used for disconnection, and The two sets of current values and voltage values measured at the time of conduction are used as the resistance between the motor's coil and the ground to detect the motor's insulation resistance value.

The motor control device according to the embodiment of the present disclosure includes: a first power supply unit; a first switch that can cut off the power supply from the first power supply unit; and a DC supply unit that connects the power supply from the first power supply unit. The power of the power supply unit is output to the bus bar; a capacitor, which is connected to the aforementioned bus bar; and a switching element, which converts the direct current supplied to the aforementioned bus bar to alternating current to drive and control the motor; wherein, it further includes: a second power supply unit, which One end is connected to the bus bar, and the other end is grounded through the second switch; the current detection unit detects the current value between the winding of the motor and the bus bar connected to the second power supply unit; and insulation The resistance calculation unit cuts off the power supply via the first switch unit, and based on the current value detected by the current detection unit and the capacitance of the capacitor during the on and off of each of the second switches The voltage value and the voltage value of the second power supply unit are used to calculate the insulation resistance value of the motor.

In the following detailed description, for the purpose of explanation, many specific details are mentioned in order to provide an in-depth understanding of the disclosed implementation modes. However, it should be understood that one or more implementation aspects can be implemented without these specific details. In other different situations, well-known structures and devices are schematically shown to simplify the drawings.

In Japanese Patent No. 4961045, in the case of detecting the insulation resistance of a plurality of motors, in a state where all the arm switching elements are interrupted, it is detected that a part of the part containing the low-voltage source, AC motor, and inverter is detected. The bias current flowing in the closed loop. Then, when any one of the selected arm switching elements is in the connected state, a closed loop current flowing in a closed loop including a low voltage source, an AC motor, and a part of the inverter section is detected. Next, by calculating the difference between the value of the closed loop current and the value of the bias current, the current based on the insulation resistance of the motor is calculated. If the insulation resistance of the motor does not decrease, no bias current will flow. On the other hand, when the insulation resistance of the motor drops, a voltage is applied to the semiconductor switching element from a low voltage source through the insulation resistance of the motor. Next, the leakage current of the semiconductor switching element flows. This current is the bias current. In Japanese Patent No. 4961045, the bias current (leakage current of the semiconductor switching element) is measured. Next, the difference between the measurement result of the closed loop current and the bias current when the selected arm switching element is in the connected state is obtained. Through this, the influence of the leakage current of the semiconductor switching element is removed. However, the measured bias current is equivalent to the full axis of the measurement axis and the non-measurement axis. For this reason, the measured bias current also includes the measured axis bias current. On the other hand, the current measured in the closed-loop current measurement is obtained by adding the current based on the insulation resistance of the motor of the measured shaft and the bias current of the entire shaft of the non-measured shaft. For this reason, the bias is removed by the difference between the closed loop current and the bias current. After this, the following calculation results are obtained. Calculation result = current based on the insulation resistance of the motor of the measured shaft + bias current of all non-measured shafts-(bias current of the measured shaft + bias current of all non-measured shafts) = of the motor based on the measured shaft The current of the insulation resistance-the bias current of the measuring shaft. For this reason, unfortunately, an error due to the offset current of the measurement shaft is generated. In this way, in the method of Japanese Patent No. 4961045, when the insulation resistance of the motor decreases, it is impossible to accurately obtain the bias current of the entire axis of the non-measurement axis. That is, unfortunately, the calculation result also includes the offset current of the measurement shaft. For this reason, unfortunately, an error due to the offset current of the measurement shaft is generated. As a result, there is a problem that the current based on the insulation resistance of the motor cannot be measured correctly.

Japanese Patent Laid-Open No. 2015-129704 is also the same as Japanese Patent No. 4961045, in which the insulation resistance of the motor is obtained from the results of the second measurement. Next, in calculating the insulation resistance of the motor from the results of the second measurement, the equivalent resistance corresponding to the leakage current of each semiconductor switching element is eliminated. Through this, the influence of the leakage current of the semiconductor switching element is eliminated. There is no error in the leakage current of the measuring shaft as in Japanese Patent No. 4961045. For this reason, the measurement accuracy is higher than the method described in Japanese Patent No. 4961045. However, in the method described in Japanese Patent Laid-Open No. 2015-129704, the voltage of the smoothing capacitor is applied to the insulation resistance of the motor. The smoothing capacitor suppresses the fluctuation of the DC voltage caused by the power supply frequency when driving the motor. For this reason, electrolytic capacitors with relatively large capacitors are used. Moreover, the internal impedance is also low. For this reason, for example, the insulation resistance of the motor is very small. Furthermore, when the negative side element of the semiconductor switching element is short-circuited and damaged, a very large current flows from the smoothing capacitor to the semiconductor switching element through the insulation deterioration part of the motor. As a result, there is a possibility that the semiconductor switching element may be damaged a second time, or the insulation deterioration part of the motor may be further deteriorated.

In addition, a bootstrap power supply may be used as a gate drive power supply for the positive side semiconductor switching element of a small-capacitance inverter. In the bootstrap supply, represented in FIG. 4, via TR4 ~ TR6 is provided with the negative side of the semiconductor switching element gate drive power S _3, a resistor Rb, diode Db, capacitor Cb, a semiconductor switching element constituting the positive side Gate drive power for TR1～TR3. Via the negative-side semiconductor switching element TR4 ~ TR6 is turned on and off by gate element TR4 ~ TR6 is switched from the negative electrode side of the semiconductor driving power source S _3, through the resistor Rb, diode Db, a charging capacitor Cb. In this way, the gate drive power supply for the semiconductor switching elements TR1 to TR3 on the positive side is constituted. In this way, when a bootstrap power supply is used to constitute the gate drive power supply for the positive side semiconductor switching elements TR1 to TR3, in the method described in Japanese Patent Laid-Open No. 2015-129704, it is regrettable that the semiconductor on the negative side of the bootstrap power supply is The gate drive power supplies of the switching elements TR4 to TR6 pass through the resistance Rb of the bootstrap power supply, the diode Db, and the capacitor Cb, and current flows to the current detection resistor for insulation resistance detection. For this reason, there is a problem of deterioration of the accuracy of insulation resistance detection.

In addition, the gate control signals of the semiconductor switching elements TR1 to TR3 on the positive side are in addition to the bootstrap power supply, and are sometimes transmitted by high withstand voltage ICs. Also in the case of using such a high voltage IC to transmit the gate control signal, unfortunately, from the negative gate side driver supply S ₃ by the high voltage power supply IC, a current flows to the current detection resistor for detecting the insulation resistance. For this reason, there is a problem of deterioration of the accuracy of insulation resistance detection.

The present invention is to resolve the above-mentioned problems. Its purpose is to provide a motor control device that has neither the risk of secondary damage to the semiconductor switching element nor the risk of further insulation degradation of the motor, which can be used as a bootstrap power supply or a high withstand voltage IC. The motor control device, furthermore, can accurately detect the insulation resistance of the motor.

A motor control device related to one aspect of the present invention for solving the aforementioned problems includes: a first power supply unit; a first switch that can cut off the power supply from the first power supply unit; a DC supply unit, It outputs the power from the first power supply unit to the bus bar; a capacitor, which is connected to the bus bar; and a switching element, which converts the DC supplied to the bus bar to AC to drive and control the motor; : The second power supply unit, which connects one end to the bus bar, and grounds the other end through the second switch; the current detection unit, which detects the winding of the motor and the bus bar connected to the second power supply unit And the insulation resistance calculation section, which cuts off the power supply via the first switch section, and when each of the second switches is opened and closed, based on the detection by the current detection section The current value, the voltage value of the capacitor, and the voltage value of the second power supply unit are used to calculate the insulation resistance value of the motor.

A motor control device related to another aspect of the present invention for solving the aforementioned problems includes: a first power supply unit, that is, a DC power supply that is not yet grounded; and a DC supply unit that receives power from the first power supply unit Output to the bus; a capacitor, which is connected to the bus; and a switching element, which converts the direct current supplied to the bus to an alternating current to drive and control the motor; wherein, it also includes: a second power supply unit, which connects one end Connected to the bus bar, ground the other end through the second switch; a current detection unit that detects the current value between the winding of the motor and the bus bar connected to the second power supply unit; and an insulation resistance calculation unit, It is based on the current value detected by the current detection unit, the voltage value of the capacitor, and the voltage value of the second power supply unit during the opening and closing of the second switch to calculate the motor's Insulation resistance value.

An insulation resistance detection method for a motor control device related to another aspect of the present invention for solving the foregoing problems, the motor control device includes: a first power supply unit; 1 Power supply of the power supply unit; DC supply unit, which outputs the power from the first power supply unit to the bus bar; capacitor, which is connected to the bus bar; and switching element, which converts the DC supply to the bus bar The insulation resistance detection method of the motor control device includes: disconnecting the power supply via the first switch; connecting one end to the bus bar, and the other end is grounded through the second switch. The second switch of the power supply unit is set to on; the current detection unit detects the first current value between the winding of the motor and the bus bar connected to the second power supply unit; set the second switch to off Use the current detection unit to detect the second current value between the winding of the motor and the bus bar connected to the second power supply unit; and, based on the detected first current value and the second current value, and The voltage value of the capacitor and the voltage value of the second power supply unit are used to calculate the insulation resistance value of the motor.

An insulation resistance detection method for a motor control device related to yet another aspect of the present invention for solving the aforementioned problems, the motor control device includes: a first power supply unit, that is, a direct current power supply that is not grounded; a direct current supply unit, which The electric power from the first power supply unit is output to the bus bar; the capacitor is connected to the bus bar; and the switching element converts the direct current supplied to the bus bar to alternating current to drive and control the motor; wherein the motor controls The insulation resistance detection method of the device includes: turning on the second switch of the second power supply part whose one end is connected to the bus bar and the other end is grounded through the second switch; using the current detection part to detect the winding of the motor, The first current value between the bus bar connected to the second power supply unit; the step of turning off the second switch; the current detection unit detects the winding of the motor and the connection to the second power supply unit The second current value between the bus bars; and, based on the detected first current value and the second current value, the voltage value of the capacitor, and the voltage value of the second power supply unit, the insulation resistance of the motor is calculated value.

Other aspects of the present invention are apparent from the description of the embodiments for implementing the types of the invention described later.

According to the present invention, the power supply from the first power supply unit is stopped by cutting off the power supply by the first switch unit. In this state, when the second switch is turned on, only the voltage of the capacitor is used to flow the leakage current through the switching element. Next, the current detection unit detects the first current value. On the other hand, in the same state that the power supply from the first power supply unit is stopped, and the second switch is turned off, the current detection unit detects that the first current value and only the second current value has been added. The second current value of most of the current flowing through the winding of the motor due to the voltage of the power supply unit (the remainder is the minute leakage current of the switching element on the negative side.). Based on the calculation of the two current values detected by the current detection unit, namely the first current value and the second current value, the voltage value of the capacitor and the voltage value of the second power supply unit, the insulation resistance of the motor can be accurately calculated. value.

Here, when the first power supply unit is a DC power supply that has not yet been grounded, the first switch unit is not provided for the time being. Moreover, there is no step of shutting off the power supply via the first switch section. However, the rest is the same.

Furthermore, according to the present invention, the voltage value of the second power supply unit is used to measure the current value passing through the winding of the motor. For this reason, as the voltage value of the capacitor used to detect the insulation resistance, it is not necessary to turn off the switching element through the gate drive control of the switching element of the drive control motor. Furthermore, the current capacity of the second power supply unit can be set to a small current capacity necessary for insulation resistance detection. For this reason, during the measurement, a very large current flows from the capacitor to the switching element on the negative side through the insulation deterioration part of the motor. There is no risk of secondary damage to the switching element, and there is no risk of further deterioration of the insulation deterioration part of the motor. .

Furthermore, the insulation resistance detection method of the motor control device related to the present invention can only stop the supply of these power sources even when the switching element of the drive control motor is driven by a bootstrap power supply or a high withstand voltage IC. The method is also applicable. For this reason, by performing the same calculation as described above, the insulation resistance value of the motor can be accurately calculated.

Moreover, here, the "1st switch" includes all switches including circuit breakers. Even the terminals or contacts that are in contact with the battery or the terminal of the power supply include all switches that have a structure that can cut off the power supply from the power supply. Moreover, the "DC supply unit" is of course not only a power converter that converts AC to DC, but also includes a power converter that converts from DC to DC or maintains voltage. However, when a directly connected DC power source is used as the first power source, connecting wires, contacts, terminals, etc. constitute a “DC supply unit”. In addition, when it is called a "switcher", the "switcher" may include any switcher in addition to the aforementioned "switcher" as long as it can stop the current. Such switches also include mechanical switches, relays, and semiconductor switches.

As described above, under the present invention, a motor control device can be provided, which is connected to the motor control device, and there is no risk of secondary damage to the switching element, and there is no risk of further insulation degradation of the motor. It is suitable for motor control devices containing bootstrap power supply or high withstand voltage IC, and furthermore, it can accurately detect the insulation resistance of the motor. Example

Fig. 1 shows the first aspect of the present invention.

Furthermore, in the following description, current may include a current value, voltage may include a voltage value, impedance may include an impedance value, and resistance may include a resistance value. Moreover, these terms are explained based on the technical common sense of persons with ordinary knowledge in the technical field. Moreover, as for the gate drive power supply of the semiconductor switching element, unless otherwise specified, a normal insulated power supply is used. For this reason, a detailed description of the gate drive power supply is omitted.

The motor control device Cont1 is composed of the following: a rectifier circuit (DC supply unit) S _DC , a bus ML composed of a positive side bus ML ₊ and a negative side bus ML _- , a smoothing capacitor (capacitor) C1, a semiconductor switch The inverter constituted by the elements TR1 to TR6, and the insulation resistance calculation unit 3 ₁ .

Phase AC voltage based on the motor control apparatus Cont1, the three-phase AC power supply (first power supply unit) S ₁ can be disconnected through an electromagnetic contactor (first switching device) supplied MS power supplied via a rectifier circuit (DC Supply part) S _DC is full-wave rectified. Then, the DC voltage is output to the bus ML.

DC voltage is output via a line is connected to the positive side of the bus line ML ML ML ₊ and negative bus side _- between a smoothing capacitor (capacitor) C1, C2, is smoothed.

Is supplied to the bus and the bus ML ₊ ML _- DC voltage that has been smoothed, is supplied to the system using a bus connected to the positive side and the negative side of the ML ₊ bus ML _- between the semiconductor switching element TR1 ~ TR6 constituted Inverter. In this way, the motor 1 is driven by the alternating current obtained by inversely converting the direct current supplied to the bus bars ML ₊ and ML _-.

The motor control device Cont2 is composed of: a bus ML composed of a positive side bus ML ₊ and a negative side bus ML _- , a smoothing capacitor (capacitor) C2, and an inverter composed of semiconductor switching elements TR7 to TR12 , And insulation resistance calculation unit 3 ₂ .

Regarding the motor control device Cont2, similar to the motor control device Cont1, the direct current voltage _{from the rectifier circuit S DC is supplied.} Furthermore, the direct current supplied to the bus bar ML is reversely converted into alternating current via an inverter constituted by the semiconductor switching elements TR7 to TR12. In this way, the motor 2 is driven.

This aspect shows a configuration suitable for two-axis driving in which the motor 1 and the motor 2 drive their respective shafts.

Insulation resistance calculating portion of the motor control device ₃₁ based Cont1 formed using the following: ML is provided in the negative-side bus line ML _- between the ground and the DC power source E (second power supply section) S _2, the switch SW0 (the first 1 switch), _{the current detection resistor R1 connected to the negative side bus ML-} and the winding L of the motor 1, and the detection control that detects the current from the voltage of the current detection resistor R1 and controls the detection action of the insulation resistance and calculates the insulation resistance value Section (current detection section) 4 ₁ .

Insulation resistance calculating portion of the motor control device ₃₂ based Cont2 is constituted by the following: line ML and the negative side line ML _- 2 and the motor winding L is connected to the current detecting resistor R2, and a voltage detected from the current detecting resistor R2 The detection control unit (current detection unit) 42 that calculates the insulation resistance value of the current.

The current detection resistors R1 and R2 may be connected to the winding L of one phase of the U-phase, V-phase, and W-phase of the motor 1 or 2 of the shaft, respectively. The resistance of the winding L of the motors 1 and 2 is very small. For this reason, any phase can be detected.

The DC power supply system S ₂ having at C1, C2 is lower than the voltage of the smoothing capacitor voltage range as high voltage power supply, with the E side of the ground potential than the negative side bus ML _- high condition. In addition, to the extent necessary for measurement, a power supply with a small current capacity is used.

Setting than the smoothing capacitor C1, the DC power source voltage lower S ₂ and C2, based in order to suppress the induced current insulation resistance Rm1, Rm2 detection accuracy of decrease, but at the current measurement from the motor 1, 2 The insulation resistances Rm1 and Rm2 flow through the flywheel diodes Df of the semiconductor switching elements TR1 to TR3 and TR7 to TR9 in the upper branch (positive side) of the inverter section to charge the smoothing capacitors C1 and C2. .

During normal motor control, the switch SW0 is kept off, and the electromagnetic contactor MS is on. Next, the motor control of each axis is performed via the inverter. At the time of insulation resistance detection, the motor control devices Cont1 and Cont2 operate as follows.

The motor control operations of all axes are stopped, the semiconductor switching elements TR1 to TR12 are turned off, and furthermore, the electromagnetic contactor MS is blocked. Next, the inverter measured DC voltage V _PN, the current detecting resistor R1 is a voltage V _R1A, and the voltage V _R2A current detecting resistor R2.

The voltages of the smoothing capacitors C1 and C2 are applied to the semiconductor switching elements TR1 to TR12 constituting the inverter. For this reason, the DC voltage V _PN of the inverter is substantially equal to the voltages of the smoothing capacitors C1 and C2. With such a voltage, current flows from the semiconductor switching element TR1 to TR4. Also, current flows to the current detection resistor R1. Likewise, current flows from the semiconductor switching element TR7 to TR10. Also, current flows to the current detection resistor R2.

The current flowing from the positive side semiconductor switching element TR1 to TR4 and the current flowing from TR7 to TR10 are the leakage currents of the semiconductor switching element. Leakage current flows in all phases in the same way. However, focusing on connecting one phase of the current detection resistors R1 and R2, the insulation resistance of the motor can be obtained through this.

The equivalent leakage resistance of the semiconductor switching element of TR1 and TR4 is determined as R _tr1 . Furthermore, the equivalent drain resistance of the semiconductor switching element of TR7 and TR10 is determined to be R _tr2 . The following equations (1) and (2) are established.

Next, the switch SW0 is set to ON, the negative side with respect to the bus ML _- voltage is applied to the DC power source VDC to the ground S ₂ E. Next, the measured current detecting resistor R1 of the voltage V _R1B, and the voltage V _R2B current detecting resistor R2.

In the case where the motor 1 has insulation deterioration of the DC power supply voltage line S ₂ through the motor insulation resistance Rm1 is applied to the semiconductor switching element TR4. Next, the current flows to the current detection resistor R1 and the semiconductor switching element TR4.

Also, in the case where the motor 2 with a deterioration of insulation, the DC power voltage line S ₂ through the insulation resistance Rm2 motor, it is applied to the semiconductor switching element TR10. Next, the current flows to the current detection resistor R2 and the semiconductor switching element TR10.

Furthermore, the voltages of the smoothing capacitors C1 and C2, that is, the DC voltage V _{PN of the} inverter, are applied to the semiconductor switching elements TR1 and TR4. For this reason, current flows from the semiconductor switching element TR1 to TR4. Moreover, current also flows to the current detection resistor R1.

Similarly, current flows from the semiconductor switching element TR7 to TR10. Moreover, current also flows to the current detection resistor R2.

These currents flowing from the semiconductor switching elements TR1 to TR4 and the currents flowing from TR7 to TR10 are the leakage currents of these semiconductor switching elements. However, the leakage current of these semiconductor switching elements is generally smaller than the current flowing due to the decrease in the insulation resistance of the motor. For this reason, it can be assumed that the voltages of the smoothing capacitors C1 and C2 hardly drop.

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

The insulation resistance Rm1 of the motor 1 can be obtained by solving the simultaneous equations of the aforementioned equations (1) and (3) using the following equations.

In addition, the insulation resistance Rm2 of the motor 2 can be obtained by solving the simultaneous equations of the aforementioned equations (2) and (4), and using the following equations.

These calculations lines _{41, 42} in the detection control section. Yet, of course, through the current detecting resistors R1, R2 of the respective voltages V _R1A, 1 V _R2A times of detection can be calculated from the insulation resistance value Rm1, Rm2. However, even if one of the two voltages V _R1A and V _R2A measured a plurality of times or various average values of the two voltages are used, there is no effect.

When such various average values are used, not only can the influence of abnormal values due to interference or the like be reduced, but also higher precision insulation resistance values Rm1 and Rm2 can be obtained.

Then, the calculated insulation resistance values Rm1 and Rm2 are transmitted to the user device as information. The transmission of the insulation resistance values Rm1 and Rm2 can be done by any means. For example, these resistance values are not affected by wired transmission or wireless transmission.

Users who know the insulation resistance values Rm1 and Rm2 can judge that insulation resistance degradation has occurred when the relevant insulation resistance value is low. Then, based on the prediction of the system shutdown caused by the motor due to the ground fault, it is possible to suppress the occurrence of such inappropriate accidents by replacing the motor in advance.

In the judgment of whether the insulation resistance is degraded, appropriate judgment means can be used. For example, the judgment can be made through the following comparisons: comparison with values known through experiments or experience, comparison with the initial values measured and recorded or memorized when the motor control device is initially set up using normal products, or, Comparison with other set values of safety standards.

The insulation resistances Rm1 and Rm2 of the motors 1 and 2 are very small. Furthermore, when the semiconductor switching elements TR4 to TR6 and TR10 to TR12 on the negative side of the semiconductor switching elements TR1 to TR12 are short-circuited and damaged, the DC power supply S _{2 is} passed through In the insulation-deteriorated parts of the motors 1 and 2, current flows to the semiconductor switching elements TR4 to TR6 and TR10 to TR12 on the negative side. However, the current capacity of the DC power source S ₂ is compared with the smoothing capacitors C1, C2, it can be very small. For this reason, the current flowing can be limited to a small current.

Therefore, there is no risk of secondary damage to the semiconductor switching elements TR4 to TR6 and TR10 to TR12 on the negative side, or the possibility of further deterioration of the insulation of the motors 1 and 2.

In the foregoing aspect, the aspect of the present invention in a motor control device using two motors 1 and 2 is explained. However, also in the case of one axis or three or more axes, the present invention can be applied similarly. As in the aforementioned aspect, also in the case of three or more axes, the DC power supply S _{2 may} be provided only on one axis.

In the foregoing aspect, the three-phase AC power supply S _{1 is} used as the first power supply unit. However, as the first power supply unit, instead of a three-phase AC power supply, a single-phase AC power supply may be used. Furthermore, in the aforementioned aspect, a rectifier circuit is used as the direct current supply unit. However, it can also be used in a circuit that can regenerate a power source such as a PWM converter. In this case, the measurement is performed after stopping the PWM converter.

Furthermore, as the first power supply unit, in addition to an AC power supply, a DC power supply such as a battery may be used. Moreover, the electromagnetic contactor may not be used. You can also use a switcher. Furthermore, if a battery is installed, when power is supplied from the battery to the motor control device, the contact or the terminal itself that is electrically connected when the battery is installed can be regarded as the first switch.

A DC power source such as a battery is used as the first power source. Furthermore, when the DC power source itself is not grounded, in principle, the first switch is unnecessary. In this case, the voltage supplied to the DC power source, the voltage of the smoothing capacitor, and the DC voltage of the inverter constituted by the semiconductor switching element are almost the same.

Furthermore, in the aforementioned aspect, as the motor control devices Cont1 and Cont2, a three-phase inverter composed of semiconductor switching elements is used. However, in the case of driving a single-phase motor, a single-phase inverter can also be used. Furthermore, the commutation method is not limited to the above-mentioned method. This method can be a full-wave bridge type or a half-wave bridge type.

Next, as a second aspect of the present invention, there is shown an aspect in which a bootstrap power supply is used.

As shown in FIG. 2, this aspect is applied to the gate drive power supply for the semiconductor switching elements TR1 to TR3 and TR7 to TR9 on the positive side of the inverter constituted by the bootstrap power supply B.

For the bootstrap power supply B used as the gate drive power supply for the semiconductor switching elements TR1 to TR3 on the positive side of the motor control device Cont1, the gate drive power supply for the semiconductor switching elements TR4 to TR6 provided on the negative side (third The power supply part) S ₃ , the resistor Rb, the diode Db, and the capacitor Cb constitute a gate drive power supply for the semiconductor switching elements TR1 to TR3 on the positive side.

Via the negative-side semiconductor switching element TR4 ~ TR6 is turned on, the switching off, the shutter element is switched from the negative electrode side of the semiconductor driving power source S _3, through the resistor Rb and the diode Db, a charging capacitor Cb. Next, a gate drive power supply for driving the gates of the semiconductor switching elements TR1 to TR3 on the positive side is realized.

In addition, the motor control device Cont2 is also configured in the same manner. TR10 ~ TR12 provided by use of a semiconductor switching element on the negative side gate drive power supply S _3, a resistor Rb, diode Db, and a capacitor Cb, the gate of the semiconductor switching element constituting the positive side TR7 ~ TR9 base drive power. The operating system of the gate drive power supply is the same as in the case of the aforementioned motor control device Cont1.

In this state, in the motor control device Cont1, a switch SW1 for interrupting the power supply is provided between the bootstrap power supply B used as the gate drive power supply of the semiconductor switching elements TR1 to TR3 on the positive side, and the bootstrap power supply B which is provided to supply power to this TR4 ~ TR6 with the negative side of the semiconductor switching element between the gate drive power source ₃ S.

Similarly, in the motor control device Cont2, a switch SW2 for interrupting the power supply is provided between the bootstrap power supply B, which uses the gate drive power supply of the semiconductor switching elements TR7 to TR9 on the positive side, and the bootstrap power supply B, which is provided on the negative side where the power is supplied. the semiconductor switching elements TR10 ~ TR12 with the gate driving power between ₃ S.

During normal motor control, the switch SW0 is turned off, SW1 and SW2 are kept on, and the electromagnetic contactor MS is on. Next, the motors 1 and 2 of each axis are driven via an inverter composed of semiconductor switching elements TR1 to TR12.

When the insulation resistance is detected, the motor control operation of all axes is stopped. The semiconductor switching elements TR1 to TR12 are turned off. Next, the electromagnetic contactor MS is shut off. The switches SW1 and SW2 are turned off. Next, the voltage of the inverter is equal to the measurement of the smoothing capacitor C DC voltage V _PN, the current detecting resistor R1 is a voltage V _R1A, and the voltage V _R2A current detecting resistor R2.

The voltage of the smoothing capacitor C is applied to the semiconductor switching elements TR1 to TR12 constituting the inverter. For this reason, current flows from the semiconductor switching element TR1 to TR4. Also, current flows to the current detection resistor R1. Likewise, current flows from the semiconductor switching element TR7 to TR10. Also, current flows to the current detection resistor R2.

The current flowing from the semiconductor switching element TR1 to TR4, and the current flowing from the semiconductor switching element TR7 to TR10 is the leakage current of these semiconductor switching elements.

The switches SW1 and SW2 are turned off. For this reason, current does not flow from the gate drive power supply S _{3 for the} negative side semiconductor switching elements TR4 to TR6 and TR10 to TR12 to the insulation through the resistor Rb of the bootstrap power supply B, the diode Db, and the capacitor Cb. Current detection resistors R1 and R2 for resistance detection.

Next, the switch SW0 is turned on, the negative side with respect to the bus ML _- voltage VDC, the DC power is applied to the ground S ₂ E. Next, the measured current detecting resistor R1 of the voltage V _R2B voltage V _R1B and a current detecting resistor R2.

In the case where the motor 1 has insulation deterioration of the DC power supply S voltage VDC ₂ is applied through the insulation resistance Rm1 of the motor to the negative side of the semiconductor switching element TR4, the current flowing into the semiconductor current detection resistor R1 and the negative side switching element TR4.

Also, in the case where the motor 2 with a deterioration of insulation, the DC power supply voltage VDC S ₂ is applied to the negative side of the semiconductor switching element TR10 through the motor insulation resistance Rm2. Next, the current flows to the current detection resistor R2 and the semiconductor switching element TR10 on the negative side.

Furthermore, the voltage V _{PN of the} smoothing capacitor C is applied to the semiconductor switching elements TR1 to TR12. For this reason, current flows from the semiconductor switching element TR1 to TR4, and the current also flows to the current detection resistor R1. Similarly, current flows from the semiconductor switching element TR7 to TR10, and the current also flows to the current detection resistor R2.

These currents flowing from the semiconductor switching elements TR1 to TR4 and the currents flowing from TR7 to TR10 are the leakage currents of these semiconductor switching elements.

However, the leakage current from the semiconductor switching element TR1 to TR4 and the leakage current from TR7 to TR10 are smaller than the current flowing due to the decrease in the insulation resistance Rm1 and Rm2 of the motor. For this reason, the voltage of the smoothing capacitor C hardly drops. From these measurement results, the insulation resistances Rm1 and Rm2 of the motors 1 and 2 can be obtained from the aforementioned equations (5) and (6), similar to the aforementioned aspect 1 of the present invention.

Furthermore, the switches SW1 and SW2 are inserted into positions that simultaneously turn on and turn off the three phases. However, it is also possible to insert switches SW1 and SW2 in any phase to form a gate drive power supply.

Furthermore, in this aspect, it is shown that the motor control devices Cont1 and Cont2 are both the bootstrap power supply B. However, the motor control device Cont2 is the bootstrap power supply B. Furthermore, even in the case where the gate power supply of the motor control device Cont1 is a normal insulated power supply, the insulation resistance can also be detected similarly except that the switch SW1 is unnecessary.

Next, as a third aspect of the present invention, there is shown an aspect in which a high withstand voltage IC driving power source is used.

As shown in FIG. 3, in this aspect, the present invention is applicable to the case where the gate control signals of the semiconductor switching elements TR1 to TR3 and TR7 to TR9 on the positive side of the inverter are transmitted by a high withstand voltage IC.

During normal motor control, the switch SW0 is turned off, SW1 and SW2 are kept on, and the electromagnetic contactor MS is turned on. Next, the motors 1 and 2 of each axis are driven via an inverter constituted by the switching elements TR1 to TR12.

When the insulation resistance is detected, the motor control operation of all axes is stopped. The semiconductor switching elements TR1 to TR12 are turned off. Next, the electromagnetic contactor MS is shut off. The switches SW1 and SW2 are turned off. Next, the voltage of the inverter is equal to the measurement of the smoothing capacitor C DC voltage V _PN, the current detecting resistor R1 is a voltage V _R1A, and the voltage V _R2A current detecting resistor R2.

The voltage of the smoothing capacitor C is applied to the semiconductor switching elements TR1 to TR12 constituting the inverter. For this reason, current flows from the semiconductor switching element TR1 to TR4. Also, current flows to the current detection resistor R1.

Likewise, current flows from the semiconductor switching element TR7 to TR10. Also, current flows to the current detection resistor R2. The current flowing from the semiconductor switching element TR1 to TR4 and the current flowing from TR7 to TR10 are the leakage currents of these semiconductor switching elements.

Set the switches SW1 and SW2 to off. For this reason, current does not flow from the gate drive power supply S _{3 for the} negative side semiconductor switching elements TR4 to TR6 and TR10 to TR12 through the power supply of the high withstand voltage IC to the current detection resistors R1 and R2 for insulation resistance detection. .

Next, the switch SW0 is turned on. Next, with respect to the negative side bus ML ₋ , the voltage VDC of the DC power supply S ₂ is applied to the ground E. Next, the measured current detecting resistor R1 of the voltage V _R1B, and the voltage V _R2B current detecting resistor R2.

From these measurement results, similar to the first and second aspects of the present invention described above, the insulation resistances Rm1 and Rm2 of the motors 1 and 2 can be obtained through the aforementioned equations (5) and (6).

Furthermore, the switches SW1 and SW2 are inserted in positions where the three phases are turned on and off at the same time. However, it is also possible to insert the switches SW1 and SW2 in any phase to form a gate drive power supply for a high withstand voltage IC.

It is also possible to use both a combined bootstrap power supply and high withstand voltage IC. Also in this case, similar to the aforementioned modes 2 and 3, the switches SW1 and SW2 are already installed to block the connection path from the gate drive power supply to both the bootstrap power supply and the high withstand voltage IC. In this way, the insulation resistances Rm1 and Rm2 of the motors 1 and 2 can be detected.

Of course, as a gate drive power supply, it is also possible to use a combination of switching elements used in ordinary insulated power supplies.

Above, the aspect of the present invention has been described in detail. However, the technical scope of the present invention is not limited to the embodiment specifically shown in the description so far. The aspects included in the matters described in the scope of the patent application include all of this embodiment. Moreover, each term and description should not be construed as limiting its technical scope.

For the purpose of illustration and description, the above detailed description has been presented. There are many modifications and variations based on the above teachings. It is not intended to exhaust or limit the subject matter of the invention described herein to the specific precise form disclosed. Although the subject matter of the invention has been described in terms of specific structural features and/or methodological behaviors, it should be understood that the subject matter of the invention defined in the scope of the attached patent application is not necessarily limited to the specific features or behaviors mentioned above. On the contrary, the above-mentioned specific features and behaviors are disclosed as embodiments of the scope of the attached patent application.

1: Motor 2: Motor 3 ₁ : Insulation resistance calculation section 3 ₂ : Insulation resistance calculation section 4 ₁ : Detection control section (current detection section) 4 ₂ : Detection control section (current detection section) B: Bootstrap power supply C: Smoothing Capacitor C1: Smoothing capacitor (capacitor) C2: Smoothing capacitor (capacitor) Cb: Capacitor Cont1: Motor control device Cont2: Motor control device Db: Diode Df: Flywheel diode E: Grounding L: Winding ML _- : Negative Bus on the side ML ₊ : Bus on the positive side MS: Electromagnetic contactor (1st switch) R1: Current detection resistor R2: Current detection resistor Rb: Resistance Rm1: Insulation resistance Rm2: Insulation resistance R _tr1 : Semiconductor switching element, etc. Price leakage resistance R _tr2 : Equivalent leakage resistance of the semiconductor switching element S ₁ : Three-phase AC power supply (first power supply section) S ₂ : DC power supply (second power supply section) S ₃ : Gate drive power supply S _DC : Rectifier circuit (DC supply part) SW0: Switch (1st switch) SW1: Switch SW2: Switch TR1: Semiconductor switching element TR10: Semiconductor switching element TR11: Semiconductor switching element TR12: Semiconductor switching element TR2: Semiconductor switching element TR3: Semiconductor switching element TR4: Semiconductor switching element TR5: Semiconductor switching element TR6: Semiconductor switching element TR7: Semiconductor switching element TR8: Semiconductor switching element TR9: Semiconductor switching element VDC: DC power supply S ₂ voltage V _PN : Inverter DC voltage (Voltage of smoothing capacitors C, C1, C2) V _R1A : Voltage of current detection resistor R1 V _R2A : Voltage of current detection resistor R2

[Fig. 1] is a circuit diagram showing a motor control device related to the first aspect of the present invention. [Fig. 2] is a circuit diagram showing a motor control device related to the second aspect of the present invention including a bootstrap power supply. Fig. 3 is a circuit diagram showing a motor control device related to the third aspect of the present invention including a high withstand voltage IC including a drive switching element. [Fig. 4] is a circuit diagram showing an example of a conventional motor control device.

1: motor

2: motor

3 ₁ : Insulation resistance calculation section

3 ₂ : Insulation resistance calculation section

_41: detection control unit (current detection unit)

_42: detection control unit (current detection unit)

C1: Smoothing capacitor (capacitor)

C2: Smoothing capacitor (capacitor)

Cont1: Motor control device

Cont2: Motor control device

E: Ground

L: Winding

ML _- : bus on the negative side

ML ₊ : bus bar on the positive side

MS: Electromagnetic contactor (1st switch)

R1: current sense resistor

R2: current sense resistor

Rm1: insulation resistance

Rm2: insulation resistance

R _tr1 : Equivalent leakage resistance of the semiconductor switching element

R _tr2 : Equivalent leakage resistance of the semiconductor switching element

S ₁ : Three-phase AC power supply (the first power supply part)

S ₂ : DC power supply (second power supply section)

S _DC : Rectifier circuit (DC supply part)

SW0: Switch (1st switch)

TR1: Semiconductor switching element

TR2: Semiconductor switching element

TR3: Semiconductor switching element

TR4: Semiconductor switching element

TR5: Semiconductor switching element

TR6: Semiconductor switching element

TR7: Semiconductor switching element

TR8: Semiconductor switching element

TR9: Semiconductor switching element

TR10: Semiconductor switching element

TR11: Semiconductor switching element

TR12: Semiconductor switching element

V _DC : Voltage of DC power supply S ₂

V _PN : DC voltage of the inverter (voltage of smoothing capacitors C, C1, C2)

V _R1A : Voltage of current detection resistor R1

Claims (9)

A motor control device with: The first power supply unit; The first switch, which can cut off the power supply from the aforementioned first power supply unit; DC supply unit, which outputs the power from the aforementioned first power supply unit to the bus; A capacitor, which is connected to the aforementioned bus; and A switching element, which converts the direct current supplied to the aforementioned bus into alternating current to drive and control the motor; Among them, it also has: The second power supply unit connects one end to the aforementioned bus bar, and the other end is grounded through the second switch; A current detection unit that detects the current value between the winding of the motor and the bus bar connected to the second power supply unit; and The insulation resistance calculation unit cuts off the power supply via the first switch unit, and when each of the second switches is opened and closed, based on the current value detected by the current detection unit, the capacitor And the voltage value of the second power supply unit to calculate the insulation resistance value of the motor. A motor control device with: The first power supply part, that is, the DC power supply that has not been grounded; DC supply unit, which outputs the power from the aforementioned first power supply unit to the bus; A capacitor, which is connected to the aforementioned bus; and A switching element, which converts the direct current supplied to the aforementioned bus into alternating current to drive and control the motor; Among them, it also has: The second power supply unit connects one end to the aforementioned bus bar, and the other end is grounded through the second switch; A current detection unit that detects the current value between the winding of the motor and the bus bar connected to the second power supply unit; and The insulation resistance calculation unit is based on the current value detected by the current detection unit, the voltage value of the capacitor, and the voltage value of the second power supply unit during the on and off periods of each of the second switches Calculate the insulation resistance value of the aforementioned motor. Such as the motor control device of claim 1 or 2, in which, The aforementioned switching element of at least one of the aforementioned motors includes a bootstrap power supply; The motor control device further includes: a third switch, which cuts off the power supply to the bootstrap power supply when the third switch is turned on; The current detection unit detects the current value when the third switch is turned on. Such as the motor control device of claim 1 or 2, in which, At least one of the aforementioned switching elements of the aforementioned motor includes a high withstand voltage IC for gate driving that transmits a gate control signal; The motor control device further includes: a third switch that cuts off the power supply to the high withstand voltage IC when the third switch is turned on; The current detection unit calculates the current value of the at least one motor when the third switch is turned on. Such as the motor control device of any one of claims 1 to 4, wherein: The aforementioned second power supply unit is connected to the aforementioned bus bar at one end of the negative side or the positive side, and the other end is grounded; The voltage of the second power supply unit is set to be lower than the voltage of the capacitor. A method for detecting insulation resistance of a motor control device, the motor control device having: The first power supply unit; The first switch, which can cut off the power supply from the aforementioned first power supply unit; DC supply unit, which outputs the power from the aforementioned first power supply unit to the bus; A capacitor, which is connected to the aforementioned bus; and A switching element, which converts the direct current supplied to the aforementioned bus into alternating current to drive and control the motor; Wherein, the insulation resistance detection method of the motor control device includes: The process of disconnecting the power supply via the aforementioned first switch; The step of turning on the second switch of the second power supply part whose one end is connected to the aforementioned bus and the other end is grounded through the second switch; A step of detecting the first current value between the winding of the motor and the bus bar connected to the second power supply unit by a current detection unit; Set the aforementioned second switch as a closed process; A step of detecting the second current value between the winding of the motor and the bus bar connected to the second power supply unit by the current detection unit; and, A step of calculating the insulation resistance value of the motor based on the detected first current value and the second current value, the voltage value of the capacitor, and the voltage value of the second power supply unit. A method for detecting insulation resistance of a motor control device, the motor control device having: The first power supply part, that is, the DC power supply that has not been grounded; DC supply unit, which outputs the power from the aforementioned first power supply unit to the bus; A capacitor, which is connected to the aforementioned bus; and A switching element, which converts the direct current supplied to the aforementioned bus into alternating current to drive and control the motor; Wherein, the insulation resistance detection method of the motor control device includes: The step of turning on the second switch of the second power supply part whose one end is connected to the aforementioned bus and the other end is grounded through the second switch; A step of detecting the first current value between the winding of the motor and the bus bar connected to the second power supply unit by a current detection unit; Set the aforementioned second switch as a closed process; A step of detecting the second current value between the winding of the motor and the bus bar connected to the second power supply unit by the current detection unit; and, A step of calculating the insulation resistance value of the motor based on the detected first current value and the second current value, the voltage value of the capacitor, and the voltage value of the second power supply unit. Such as the insulation resistance detection method of the motor control device of claim 6 or 7, wherein: The aforementioned motor control device further includes: the aforementioned switching element, which is further equipped with at least one bootstrap power supply; and a third switch, which cuts off the power supply to the aforementioned bootstrap power supply when it is turned on; The step of detecting the first current value and the step of detecting the second current value are performed when the third switch is turned on. Such as the insulation resistance detection method of the motor control device of claim 6 or 7, wherein: The motor control device further includes: the switching element, which is further equipped with at least one high withstand voltage IC for transmitting gate control signals and driving the gate; and a third switch, which is turned off to the high withstand voltage when turned on Voltage IC power supply; The step of detecting the first current value and the step of detecting the second current value are performed when the third switch is turned on.

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