JP2007215351A - Alarm signal output device, load protector and alarm signal output method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an alarm signal output device suitable for preventing current supply to a load when troubles occur. <P>SOLUTION: A power amplifier substrate 3 is connected to power supplies 1a, 1b, a motor 2, and a control substrate 6. The power amplifier substrate 3 includes photocouplers PC1 to PC3 for outputting driving signals based on a current command signal from the control substrate 6, a motor driving circuit 39 for providing a current from the power supply 1a based on the driving signals with the motor 2, an alarm circuit 35 for outputting an alarm signal when an abnormality occurs in a driving current to the motor 2, a latch circuit 36 for latching the alarm signal from the alarm circuit 35, a photocoupler PC4 for interrupting current supply to the motor 2 when the alarm signal latched in the latch circuit 36 is inputted, and a relay 40. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus and method for outputting an alarm signal in the event of an abnormal current, and in particular, an alarm signal output apparatus and a load protection apparatus suitable for preventing a current supply to a load when a failure or the like occurs, and an alarm signal output Regarding the method.

  Conventionally, for example, a technique described in Patent Document 1 is known as a motor control device including a plurality of substrates. The technology described in Patent Document 1 constitutes a power amplifier board that drives a motor by supplying a current from a power supply to the motor, and the motor control device connects the control board to the power amplifier board. It can be configured as shown in FIG.

FIG. 6 is a block diagram showing a configuration of a conventional motor control device.
As shown in FIG. 6, the conventional motor control device includes power supplies 1 a and 1 b made of AC power, a motor 2 made of a direct drive motor, a power amplifier board 300 that drives the motor 2, and a control for controlling the motor 2. And a substrate 600. The power amplifier board 300 is connected to the power supplies 1a and 1b and the motor 2, and the power amplifier board 300 and the control board 600 are connected via signal lines.

The power amplifier board 300 includes a signal processing unit 310 that processes a signal from the control board 600 and a power supply unit 320 that supplies power to the motor 2.
The signal processing unit 310 includes a switching regulator 33, photocouplers PC <b> 1 to PC <b> 3 that receive a power supply from the switching regulator 33 and perform a switching operation, and an alarm circuit 350. When the current command signal from the control board 600 is at a low level, the photocouplers PC1 to PC3 output a drive signal to supply current to the motor 2, and the current command signal from the control board 600 is at a high level. At this time, a drive signal that should cut off the current supply to the motor 2 is output.

The power supply unit 320 includes a rectifier 38 that rectifies the AC power of the power source 1a into a direct current, a smoothing capacitor C that smoothes the output of the rectifier 38, and a smoothing capacitor C based on drive signals from the photocouplers PC1 to PC3. And a motor drive circuit 39 for supplying a smoothed current to the motor 2.
The alarm circuit 350 detects a drive current to the motor 2 and outputs an alarm signal for stopping the drive of the motor 2 when the detected drive current exceeds the limit current value of the motor 2.

  The control board 600 is configured to include a current command output circuit 61 and a CPU 62 that operate by receiving power supplied from the power amplifier board 300, and a fuse 63 provided in the power supply line L 2 connected to the switching regulator 33. ing. The control board 600 has a power supply terminal T28 connected to the power supply line L2 through the fuse 63 and supplying power to an operation terminal (not shown), and an operation signal input terminal for inputting an operation signal from the operation terminal. T29 is provided.

The CPU 62 outputs a control signal to the current command output circuit 61 based on the operation signal input from the operation signal input terminal T29. When an alarm signal from the alarm circuit 350 is input, a control signal for setting the current command signal to a high level is output to the current command output circuit 61.
The current command output circuit 61 outputs a current command signal based on a control signal from the CPU 62.
Japanese Patent Application Laid-Open No. 2001-231211

However, in the conventional motor control device, when a failure or the like occurs in the current command output circuit 61 and all the current command signals become low level, the drive signals to be supplied to the motor 2 by the photocouplers PC1 to PC3 are generated. The maximum drive current is supplied to the motor 2. Thereafter, when the drive current to the motor 2 exceeds the limit current value, the alarm circuit 350 operates and an alarm signal is output. However, since a failure or the like has occurred in the current command output circuit 61, the current command signal is There was a problem that the maximum drive current would continue to flow through the motor 2 because it could not be controlled.
Therefore, the present invention has been made paying attention to such an unsolved problem of the conventional technology, and is an alarm signal output device suitable for preventing current supply to a load when a failure or the like occurs. Another object of the present invention is to provide a load protection device and an alarm signal output method.

In order to achieve the above object, an alarm signal output device according to claim 1 of the present invention is an alarm signal output device applied to a load operating device that supplies a current from a power source to a load and operates the load. When an abnormality occurs in the current supplied to the load, an alarm signal output means for outputting an alarm signal to stop the operation of the load, and an alarm for holding an alarm signal from the alarm signal output means Signal holding means.
With such a configuration, in the load operating device, the current from the power source is supplied to the load, and the load operates.

Next, when an abnormality occurs in the current supplied to the load during operation of the load, an alarm signal is output by the alarm signal output means, and the alarm signal is held by the alarm signal holding means. Therefore, if the alarm signal held by the alarm signal holding means is used, current supply to the load can be prevented.
Here, the operation means that the load is operated with generation of power and the load is operated without generation of power. The former load includes, for example, a motor and an actuator. The latter load includes, for example, an electronic circuit and a semiconductor device. Hereinafter, the load protection device according to claim 2 and the alarm signal output method according to claim 5 are the same.

  In addition, as an abnormality in the current supplied to the load, for example, when the current supplied to the load exceeds the limit current value of the load and the current supplied to the load exceeds the maximum operating current. The case where it continues for a predetermined time can be considered. When the current supplied to the load is composed of at least three sets of waveforms having different phases, at least two of the waveforms of the current supplied to the load have a voltage equal to or higher than a predetermined value. The case is considered. Furthermore, when the current command signal indicating the command value of the current to be supplied to the load is composed of at least three sets of waveforms having different phases, the voltages of at least two sets of waveforms among the waveforms of the current command signal are both. The case where it becomes more than predetermined value or below predetermined value can be considered. Hereinafter, the load protection device according to claim 2 and the alarm signal output method according to claim 5 are the same.

  On the other hand, in order to achieve the above object, a load protection device according to claim 2 according to the present invention includes a power supply board for operating the load by supplying current from a power source to the load, and power from the power supply board. A control board that operates in response to the supply of power and controls the load, and overcurrent protection means provided in a current path that transmits power from the power supply board to the control board, the control board comprising: A current command signal output means for outputting a current command signal indicating a command value of a current to be supplied to the load, wherein the power supply board outputs an operation signal based on the current command signal from the control board; And a load operating device that supplies a current from the power source to the load based on an operation signal from the operation signal output unit, wherein the power supply board is connected to the load. When an abnormality occurs in the supplied current, an alarm signal output means for outputting an alarm signal for stopping the operation of the load, and an alarm signal holding means for holding an alarm signal from the alarm signal output means are provided. .

With such a configuration, when a power source is connected to the power supply board, power is supplied to the control board via the power supply board. In the control board, the current command signal output means operates upon receiving power supply from the power supply board, and the current command signal is output by the current command signal output means.
In the power supply board, when the current command signal is input, the operation signal output means outputs the operation signal based on the input current command signal, and the load operation means outputs the current from the power source based on the operation signal. Supplied to the load. When current is supplied to the load, the load is activated.

Next, when an overcurrent occurs in a current path for transmitting power from the power supply board to the control board, the power supply to the control board is cut off by the overcurrent protection means. Due to this power interruption, for example, a current command signal for supplying current to the load is output from the current command signal output means, and if an abnormality occurs in the current supplied to the load, an alarm signal is output by the alarm signal output means. The alarm signal is held by the alarm signal holding means. Therefore, even if the control board becomes inoperable due to overcurrent, the current supply to the load can be prevented by using the alarm signal held by the alarm signal holding means.
Here, the overcurrent protection means only needs to be provided in a current path for transmitting power from the power supply board to the control board, and can be provided in any place other than the power supply board, the control board and the like.
The overcurrent protection means includes, for example, a fuse, a breaker, an electromagnetic switch, and an electromagnetic contactor.

Furthermore, the load protection device according to claim 3 according to the present invention is the load protection device according to claim 2, wherein the power supply board receives the alarm signal held by the alarm signal holding means. Current supply interruption means for interrupting current supply to the load is provided.
With this configuration, when an alarm signal is input, current supply to the load is interrupted by the current supply interrupting means.

  Furthermore, the load protection device according to claim 4 according to the present invention is the load protection device according to any one of claims 1 to 3, wherein the control board is configured to provide the current path via the overcurrent protection means. A power supply terminal for supplying power to the operation device, an operation signal input terminal for inputting an operation signal from the operation device, and the current command signal output based on the operation signal input from the operation signal input terminal Control means for controlling the means.

With such a configuration, when the operating device is connected to the control board and an operation signal is input by operating the operating device, the current command signal output unit is controlled by the control unit based on the input operation signal. The
Next, when a failure or the like occurs in the operating device and an overcurrent occurs in a current path for transmitting power from the power supply board to the control board, the power supply to the control board is cut off by the overcurrent protection means.

  On the other hand, in order to achieve the above object, an alarm signal output method according to claim 5 according to the present invention is applied to a load operating device that supplies current from a power source to a load and operates the load. When an abnormality occurs in the current supplied to the load, an alarm signal output step for outputting an alarm signal to stop the operation of the load, and an alarm signal output in the alarm signal output step Holding an alarm signal holding step.

As described above, according to the alarm signal output device of the first aspect of the present invention, when an abnormality occurs in the current supplied to the load due to the occurrence of a failure or the like, the alarm signal output means operates. Since the alarm signal is held, it is possible to prevent the current from being supplied to the load when a failure or the like occurs.
On the other hand, according to the load protection device according to claim 2 of the present invention, when an overcurrent occurs in the current path for transmitting power from the power supply board to the control board, and an abnormality occurs in the current supplied to the load. Since the alarm signal output means operates and the alarm signal is held, it is possible to prevent the supply of current to the load even if the control board becomes inoperable when a failure or the like occurs.

Furthermore, according to the load protection device according to claim 3 of the present invention, when an abnormality occurs in the current supplied to the load, the current supply to the load is cut off, so that when a failure or the like occurs, the load is protected. Thus, it is possible to more reliably prevent the current supply.
Furthermore, according to the load protection device according to claim 4 of the present invention, when an overcurrent is generated due to a failure or the like in the operating device, the control board can be protected from the overcurrent and the load is supplied to the load. The effect that current supply can be prevented is obtained.
On the other hand, according to the alarm signal output method of the fifth aspect of the present invention, the same effect as the alarm signal output device of the first aspect can be obtained.

Embodiments of the present invention will be described below with reference to the drawings. 1 to 5 are diagrams showing an embodiment of an alarm signal output device, a load protection device, and an alarm signal output method according to the present invention.
In the present embodiment, the alarm signal output device, the load protection device, and the alarm signal output method according to the present invention are applied to the case of controlling the motor 2 as shown in FIG.

First, the configuration of a motor control device to which the present invention is applied will be described.
FIG. 1 is a block diagram showing the configuration of the motor control device according to the present embodiment.
As shown in FIG. 1, the motor control device controls power supplies 1 a and 1 b made of AC power, a motor 2 made of a direct drive motor, a power amplifier board (PA) 3 that drives the motor 2, and the motor 2. A control board (CB) 6 and an operation terminal 7 for operating the control board 6 are provided. As the direct drive motor, for example, the one disclosed in Japanese Patent Laid-Open No. 2003-153510 can be used.

The power amplifier board 3 is connected to power sources 1 a and 1 b and a motor 2.
The power amplifier board 3 has an input terminal T11 for inputting a current command signal indicating a command value for a U-phase current, an input terminal T12 for inputting a current command signal indicating a command value for a V-phase current, An input terminal T13 for inputting a current command signal indicating a current command value, an input terminal T14 for inputting a PWMON signal indicating that the control board 6 is being activated, and a power supply terminal T15 for supplying power to the control board 6 A ground terminal T16 and an output terminal T17 for outputting an alarm signal. The control board 6 includes an output terminal T21 for outputting a U-phase current command signal, an output terminal T22 for outputting a V-phase current command signal, an output terminal T23 for outputting a W-phase current command signal, and a PWMON signal. Output terminal T24, power input terminal T25, ground terminal T26 connected to the ground of the control board 6, and input terminal T27 for inputting an alarm signal. The input terminal T11 and the output terminal T21 are connected by a signal line. Similarly, input terminal T12 and output terminal T22, input terminal T13 and output terminal T23, input terminal T14 and output terminal T24, power supply terminal T15 and power input terminal T25, ground terminal T16 and ground terminal T26, and output terminal T17 The input terminals T27 are also connected by signal lines.

The control board 6 includes a power supply terminal T28 for supplying power to the operation terminal 7, an operation signal input terminal T29 for inputting an operation signal from the operation terminal 7, and an abnormality for confirming whether the control board 6 is abnormal. Confirmation terminals T2a and T2b are provided. The operation terminal 7 is connected to the power supply terminal T28, the operation signal input terminal T29, and the abnormality confirmation terminals T2a and T2b.
The power amplifier board 3 includes a signal processing unit 31 that processes a signal from the control board 6 and a power supply unit 32 that supplies power to the motor 2.

  The signal processing unit 31 outputs a switching regulator 33 that generates a DC current of a predetermined voltage from the AC power of the power source 1b, photocouplers PC1 to PC4 that perform a switching operation upon receiving power supply from the switching regulator 33, and output an alarm signal. And an alarm circuit 35 that latches the alarm signal from the alarm circuit 35, and an OR circuit 37 that calculates the logical sum of the output signal of the latch circuit 36 and the PWMON signal from the input terminal T14. Has been.

  Photocouplers PC1 to PC3 have a function of outputting drive signals corresponding to the U-phase, V-phase, and W-phase current command signals. One end of each of the photocouplers PC1 to PC3 is connected to the power supply line of the switching regulator 33, and the other end is connected to the input terminals T11 to T13 via the resistors R1 to R3, respectively. The photocouplers PC1 to PC3 output a drive signal to supply current to the motor 2 when the current command signal is at a low level, and supply current to the motor 2 when the current command signal is at a high level. A drive signal to be cut off is output.

The OR circuit 37 outputs a high level signal when either the output signal of the latch circuit 36 or the PWMON signal from the input terminal T14 is at a high level, and otherwise outputs a low level signal. Output.
The photocoupler PC4 has a function of outputting a switching signal for switching presence / absence of power supply to the power supply unit 32 based on the output signal of the OR circuit 37. One end of the photocoupler PC4 is connected to the power supply line of the switching regulator 33, and the other end is connected to the OR circuit 37 via the resistor R4. The photocoupler PC4 outputs a switching signal to supply power to the power supply unit 32 when the output signal of the OR circuit 37 is at a low level, and the power signal when the output signal of the OR circuit 37 is at a high level. The switching signal which should interrupt | block the electric power supply to the supply part 32 is output.

The power supply terminal T15 is connected to the power supply line of the switching regulator 33 through the power supply line L1, and the ground terminal T16 is connected to the ground of the power amplifier board 3.
A fuse 34 that blows when a predetermined current flows is provided on the power supply line of the switching regulator 33 and before the contact with the power supply line L1 (on the switching regulator 33 side). Since this place is a power supply line shared by the power supply line to the photocouplers PC1 to PC3 and the power supply line to the control board 6, the fuse 34 is blown to supply power to the control board 6 and to the photocouplers PC1 to PC3. The power supply can be cut off at once.

  A bleeder resistor RBB is connected between the switching regulator 33 and the fuse 34 in parallel with the switching regulator 33. The bleeder resistor RBB has a function of suppressing the increase of the terminal voltage of the switching regulator 33 and stabilizing the switching regulator 33 by flowing a current from the switching regulator 33 when the fuse 34 is blown. Further, by diverting a part of the inrush current generated when the power supply 1b is connected to the power amplifier board 3, the photocouplers PC1 to PC4 are protected from the inrush current and the switching regulator 33 is stabilized.

The alarm circuit 35 detects the drive current to the motor 2, and when the detected drive current has exceeded the maximum drive current value for a predetermined time T and when the detected drive current has exceeded the limit current value. At this time, an alarm signal is output to the output terminal T17 and the latch circuit 36.
The power supply unit 32 includes a rectifier 38 that rectifies the AC power of the power source 1a into a direct current, a smoothing capacitor C that smoothes the output of the rectifier 38, and a motor drive circuit that supplies the motor 2 with a current smoothed by the smoothing capacitor C. 39, the relay 40 provided in the power supply line of the power supply 1a and the rectifier 38, and the inrush current prevention resistor 41 connected in parallel with the relay 40.

The motor drive circuit 39 includes an inverter circuit 39a and an FET gate drive circuit 39b.
The inverter circuit 39a includes a first series circuit in which two field effect transistors FET1 and FET2 are connected in series, and a second series circuit of two field effect transistors FET3 and FET4 connected in parallel with the first series circuit. And a three-phase AC inverter circuit comprising a third series circuit of two field effect transistors FET5 and FET6 connected in parallel with the first series circuit. Then, the switching operation is performed by the gate drive signal supplied from the FET gate drive circuit 39b, the DC voltage between the PL line and the NL line connected to the smoothing capacitor C is converted into three-phase AC power, the UL line of the motor 2, A three-phase AC voltage is output between the VL line and the WL line.

The FET gate drive circuit 39b generates a gate drive signal based on the drive signals from the photocouplers PC1 to PC3, and outputs the generated gate drive signal to the inverter circuit 39a.
When a switching signal to supply power to the power supply unit 32 is input from the photocoupler PC 4, the relay 40 closes the contact and turns on the power supply line of the power source 1 a and the rectifier 38 to supply power to the power supply unit 32. When a switching signal to be cut off is input from the photocoupler PC4, the contact is opened and the inrush current prevention resistor 41 is connected to the power source 1a and the power source line of the rectifier 38.

The inrush current prevention resistor 41 can be constituted by a cement resistor in which a resistance wire is wound around a ceramic bobbin, a thermal fuse and a resistance wire are connected in series, and they are sealed with cement.
The control board 6 includes a current command output circuit 61 and a CPU 62 that operate by receiving power from the power amplifier board 3, and a photocoupler PC5 that performs switching operation by receiving power from the power amplifier board 3. It is configured.
The current command output circuit 61, the CPU 62, and the power supply terminal T28 are connected to the power input terminal T25 through the power supply line L2.

  The photocoupler PC5 has a function of outputting the presence / absence of abnormality of the control board 6. One end of the photocoupler PC5 is connected to the CPU 62, and the other end is connected to the power supply line L2 via the resistor R5. When the PWMON signal from the CPU 62 is at a low level, the photocoupler PC5 outputs a normal message by short-circuiting between the abnormality confirmation terminals T2a and T2b. When the PWMON signal from the CPU 62 is at a high level, the photocoupler PC5 is abnormal. The confirmation terminals T2a and T2b are opened and an abnormality is output. The operation terminal 7 can confirm the presence / absence of an abnormality in the control board 6 by detecting a short circuit / opening between the abnormality confirmation terminals T2a and T2b.

  The CPU 62 is connected to an RDC (Resolver Digital Converter) (not shown) that detects the rotational angle position of the motor 2 as position detection data with a predetermined resolution based on a resolver signal from a resolver (not shown) attached to the motor 2. Then, a control signal is output to the current command output circuit 61 based on the operation signal input from the operation signal input terminal T29 and the position detection data from the RDC. For example, when an operation signal for increasing / decreasing the rotation speed of the motor 2 is input, a speed command signal is calculated based on the input operation signal and position detection data, and the current command output circuit 61 uses the calculated speed command signal as a control signal. Output to.

When the CPU 62 receives an alarm signal from the input terminal T27, the CPU 62 latches the alarm signal by software processing, outputs a high level PWMON signal, and outputs a control signal for setting the current command signal to a high level as a current command output circuit. To 61.
The current command output circuit 61 outputs a current command signal based on a control signal from the CPU 62. For example, when a speed command signal is input, a current command value is calculated for each phase so that the rotation speed of the motor 2 matches the speed command value, and a current command signal indicating the calculated current command value is output.

Next, the configuration of the alarm circuit 35 will be described.
FIG. 2 is a block diagram showing a circuit configuration of the alarm circuit 35.
The alarm circuit 35 is configured corresponding to each phase of the motor 2 as shown in FIG.
The U-phase system includes a current sensor 70a that converts the current of the UL line of the motor 2 into a voltage value, a filter circuit 71a that removes noise from the output signal of the current sensor 70a, and an integration that integrates the output voltage of the filter circuit 71a. The circuit 72a and comparators 73a and 74a are included.

  For example, the current sensor 70a amplifies the potential difference between both ends of the shunt resistor connected in series to the UL line of the motor 2 by an amplifier, and outputs a sensor signal having a voltage corresponding to the drive current flowing through the UL line. The sensor signal can take a positive or negative voltage value with reference to zero potential. In addition to this, a non-contact type current sensor using a Hall element or the like can also be used.

  An integration circuit 72a is connected to the plus input of the comparator 73a, and a power supply line of the reference voltage VT1 corresponding to the maximum drive current value and the integral value of the predetermined time T is connected to the minus input of the comparator 73a. . The comparator 73a outputs a low level signal when the output voltage of the integrating circuit 72a is lower than the reference voltage VT1, and the high level signal when the output voltage of the integrating circuit 72a is higher than the reference voltage VT1. Output. That is, a high level signal is output when the state where the current of the UL line is equal to or greater than the maximum drive current value continues for a predetermined time T.

  The filter circuit 71a is connected to the plus input of the comparator 74a, and the power source line of the reference voltage VT2 corresponding to the limit current value is connected to the minus input of the comparator 74a. The comparator 74a outputs a low level signal when the output voltage of the filter circuit 71a is lower than the reference voltage VT2, and outputs a high level signal when the output voltage of the filter circuit 71a is higher than the reference voltage VT2. Output. That is, a high-level signal is output when the current of the UL line exceeds the limit current value.

The V-phase system includes a current sensor 70b, a filter circuit 71b, an integration circuit 72b, and comparators 73b and 74b. These have the same function as each part 70a-74a in the system of U phase. The difference is that the current of the VL line of the motor 2 is targeted.
The W-phase system includes a current sensor 70c, a filter circuit 71c, an integration circuit 72c, and comparators 73c and 74c. These have the same function as each part 70a-74a in the system of U phase. The difference is that the current of the WL line of the motor 2 is targeted.

The alarm circuit 35 further includes an OR circuit 75a that calculates a logical sum of the output signals of the comparators 73a to 73c, an OR circuit 75b that calculates a logical sum of the output signals of the comparators 74a to 74c, and OR circuits 75a and 75b. And an OR circuit 76 for calculating the logical sum of the output signals.
The OR circuit 75a outputs a high level signal when any of the output signals of the comparators 73a to 73c is at a high level. That is, a high level signal is output when the current of any of the UL line, VL line, and WL line is equal to or greater than the maximum drive current value for a predetermined time T.
The OR circuit 75b outputs a high level signal when any of the output signals of the comparators 74a to 74c is at a high level. That is, a high-level signal is output when the current of any of the UL line, VL line, and WL line exceeds the limit current value.

Next, the operation of the alarm circuit 35 will be described.
FIG. 3 is a time chart showing the change over time of the drive current to the motor 2.
For the motor 2, as shown in FIG. 3, a rated current value IT1, a maximum drive current value IT2, and a limit current value IT3 are defined. The rated current value IT1 is the smallest and the limit current value IT3 is the largest. The graph of FIG. 3 shows, for example, the change over time from the time when the CPU 62 determined to stop driving the motor 2 as the origin.

  In the graph of FIG. 3, the upper right hatched area is set as an alarm area. The alarm region is defined by the capacitance of the integrating circuits 72a to 72c and the reference voltage VT1. Therefore, the alarm area includes an area that is equal to or greater than the maximum drive current value IT2 in a time zone in which a predetermined time T has elapsed from the origin. When the drive current to the motor 2 changes with time and belongs to the alarm region, the alarm circuit 35 outputs an alarm signal.

FIG. 4 is a flowchart showing the operation of the alarm circuit 35.
First, as shown in FIG. 4, the process proceeds to step S10 to detect the drive current to the motor 2, and the process proceeds to step S12 to determine whether or not the detected drive current is greater than or equal to the limit current value IT3. When it is determined that the current value is greater than or equal to the limit current value IT3 (Yes), the process proceeds to step S14 and an alarm signal is output.

On the other hand, when it is determined in step S12 that the drive current is less than the limit current value IT3 (No), the process proceeds to step S16 to determine whether or not the drive current value belongs to the alarm area. When it is determined that it belongs to (Yes), the process proceeds to step S14.
On the other hand, when it is determined in step S16 that the value of the drive current does not belong to the alarm region (No), the process proceeds to step S10.

Next, the operation of the present embodiment will be described.
When the power supplies 1 a and 1 b are connected to the power amplifier board 3, power is supplied to the control board 6 through the power amplifier board 3. At this time, when an inrush current is generated, a part of the inrush current flows through the bleeder resistor RBB, so that the inflow of overcurrent to the photocouplers PC1 to PC4 is suppressed and the switching regulator 33 is stabilized.
In the control board 6, the current command output circuit 61 operates upon receiving power supply from the power amplifier board 3, and the current command output circuit 61 outputs a current command signal.

In the power amplifier board 3, when a current command signal is input, the photocouplers PC1 to PC3 output a drive signal based on the input current command signal, and the motor drive circuit 39 outputs a power supply 1a based on the drive signal. Is supplied to the motor 2. When a current is supplied to the motor 2, the motor 2 is driven.
Next, when a failure or the like occurs in the operation terminal 7 while the motor 2 is being driven and an overcurrent is generated in the power supply line L2, the fuse 34 is blown to supply power to the control board 6 and to the photocouplers PC1 to PC3. The power supply is interrupted at once. For this reason, since the photocouplers PC1 to PC3 do not output a drive signal for supplying current to the motor 2, the motor drive circuit 39 cuts off the current supply to the motor 2.
When the fuse 34 is blown, the current from the switching regulator 33 flows through the bleeder resistor RBB, so that the switching regulator 33 is stabilized.

FIG. 5 is a time chart showing the change with time of the output signal of each part.
On the other hand, even if the fuse 34 is blown, a failure or the like occurs in the motor drive circuit 39, the maximum drive current is supplied to the motor 2, and if this state continues for a predetermined time T, an alarm is generated as shown in FIG. The circuit 35 outputs an alarm signal, and the latch circuit 36 latches the alarm signal. At this time, since the supply of power to the control board 6 is interrupted, the CPU 62 cannot operate. However, since the latch circuit 36 latches the alarm signal, the photocoupler PC4 supplies the power to the power supply unit 32. A switching signal for shutting off the power supply is output. The inrush current prevention resistor 41 is connected to the power source 1 a and the power source line of the rectifier 38 by the relay 40. When an overcurrent flows through the inrush current prevention resistor 41, the internal temperature fuse is blown. As a result, the current supply to the motor 2 is interrupted, and the driving of the motor 2 is stopped.

If the motor drive circuit 39 is faulty even though the fuse 34 is blown, and the drive current to the motor 2 exceeds the limit current value, an alarm signal is output from the alarm circuit 35 as shown in FIG. Is output. As a result, the current supply to the motor 2 is similarly cut off, so that the driving of the motor 2 is stopped.
Thus, in this embodiment, when an abnormality occurs in the drive current to the motor 2, the alarm circuit 35 that outputs an alarm signal and the latch circuit 36 that latches the alarm signal from the alarm circuit 35 are provided. Prepare.
As a result, when an overcurrent occurs in the power supply line L2 and an abnormality occurs in the drive current to the motor 2, the alarm circuit 35 operates and the alarm signal is held. Even if the operation becomes impossible, current supply to the motor 2 can be prevented.

Furthermore, in the present embodiment, when the alarm signal latched by the latch circuit 36 is input, the photocoupler PC4 and the relay 40 that cut off the current supply to the motor 2 are provided.
As a result, when an abnormality occurs in the drive current to the motor 2, the current supply to the motor 2 is interrupted, so that the current supply to the motor 2 can be more reliably prevented when a failure or the like occurs.

Furthermore, in the present embodiment, the alarm circuit 35 outputs an alarm signal when the state where the drive current to the motor 2 is equal to or greater than the maximum drive current value continues for a predetermined time T.
As a result, even if the drive current to the motor 2 is equal to or less than the limit current value due to the occurrence of a failure or the like, the alarm circuit 35 operates when the state where the value exceeds the maximum drive current value continues for a predetermined time T. Thus, current supply to the motor 2 can be prevented when a failure or the like occurs.

Further, in the present embodiment, the alarm circuit 35 outputs an alarm signal when the drive current to the motor 2 becomes equal to or greater than the limit current value.
As a result, when the drive current to the motor 2 exceeds the limit current value due to the occurrence of a failure or the like, the alarm circuit 35 operates, so that the supply of current to the motor 2 can be prevented when a failure or the like occurs. it can.
Further, in the present embodiment, the alarm circuit 35 is configured by hardware.
Thereby, the tolerance to a fault becomes high, and the current supply to the motor 2 can be more reliably prevented when a fault or the like occurs.

Further, in the present embodiment, the fuse 34 is provided in the power supply line shared by the power supply line from the switching regulator 33 to the photocouplers PC1 to PC3 and the power supply line to the control board 6.
As a result, when an overcurrent is generated in the power supply line L2, the power supply to the control board 6 and the power supply to the photocouplers PC1 to PC3 are collectively cut off, and the output of the drive signal to which the current is to be supplied is suppressed. Therefore, the control board 6 can be protected from overcurrent, and current supply to the motor 2 can be prevented.

Furthermore, in this embodiment, a bleeder resistor RBB is provided between the switching regulator 33 and the fuse 34.
Thereby, when the fuse 34 is blown, an increase in the terminal voltage of the switching regulator 33 can be suppressed and the switching regulator 33 can be stabilized. Further, when an inrush current occurs, the photocouplers PC1 to PC4 can be protected from the inrush current and the switching regulator 33 can be stabilized.

Further, in the present embodiment, the control board 6 is connected to the power supply line L2 through the fuse 34 and supplies power to the operation terminal 7 and the operation signal from the operation terminal 7 is input. And an operation signal input terminal T29 for controlling the current command output circuit 61 based on the operation signal input from the operation signal input terminal T29.
As a result, when a fault or the like occurs in the operation terminal 7 and an overcurrent occurs, the control board 6 can be protected from the overcurrent and current supply to the motor 2 can be prevented.

  In the above embodiment, the motor 2 corresponds to the load described in claims 1 to 3 or 5, the power amplifier board 3 corresponds to the power supply board described in claim 2 or 3, and the photocouplers PC1 to PC3 are The motor drive circuit 39 corresponds to the load operating means described in claim 2. The fuse 34 corresponds to the overcurrent protection means according to claim 2 or 4, the alarm circuit 35 corresponds to the alarm signal output means according to claim 1 or 2, and the latch circuit 36 corresponds to the claims 1 to 2. The photocoupler PC4 and the relay 40 correspond to the current supply cut-off means described in claim 3.

In the above embodiment, the current command output circuit 61 corresponds to the current command signal output means according to claim 2 or 4, the CPU 62 corresponds to the control means according to claim 4, and the operation terminal 7 is The power supply terminal T28 corresponds to the power supply terminal according to the fourth aspect.
In the above embodiment, the alarm circuit 35 is configured to detect the current of the UL line, the VL line, and the WL line. However, the present invention is not limited to this, and the following two configurations can be proposed.

The first configuration detects the drive signals from the photocouplers PC1 to PC3, and outputs an alarm signal when the drive signal output to the motor 2 that exceeds the maximum drive current value continues for a predetermined time T. To do.
In the second configuration, a current command signal from the current command output circuit 61 is detected, and an alarm signal is output when the output of a current command signal for which the drive current to the motor 2 is equal to or greater than the maximum drive current value continues for a predetermined time T. Is output.
The third configuration detects a current command signal from the current command output circuit 61, and outputs an alarm signal when each detected current command signal is at a low level.

In the above embodiment, the motor 2 is a direct drive motor. However, a VR direct drive motor may be used.
The VR type direct drive motor is a unipole type in which three phases are constituted by independent windings, and is driven by supplying three sets of pulse wave currents having different phases. The drive current of each phase is 120 ° out of phase, and one phase or two phases can be in a high level state.

  The alarm circuit 35 outputs an alarm signal when the drive current to the motor 2 becomes a high level and when the drive current to the motor 2 exceeds the limit current value. Specifically, the alarm circuit 35 includes an AND circuit that calculates a logical product of output signals of the filter circuits 71a to 71c in addition to the current sensors 70a to 70c, the filter circuits 71a to 71c, the comparators 74a to 74a, and the OR circuit 75b. And an OR circuit that calculates the logical sum of the output signals of the AND circuit and the OR circuit 75b.

As a result, even if the drive current to the motor 2 is lower than the limit current value due to the occurrence of a failure or the like, the current value to the motor 2 is abnormal if the drive current to the motor 2 is at a high level. Since the alarm circuit 35 operates, it is possible to prevent current supply to the motor 2 when a failure or the like occurs.
In the above embodiment, the relay 40 is operated so as to open and close the contact when an abnormality occurs in the drive current to the motor 2. However, the present invention is not limited to this, and before the power source 1a is connected to the rectifier 38. It is also possible to operate so that the contact is closed after a predetermined time has elapsed since the power supply 1a is connected (for example, when a low-level PWMON signal is input).

Thus, when an inrush current is generated due to the connection of the power source 1a, the motor drive circuit 39 can be protected from the inrush current and the rectifier 38 can be stabilized.
Moreover, in the said embodiment, although the alarm signal was used for the use which interrupts | blocks the electric current supply to the motor 2, it is not restricted to this, It should be used for every use if it is a use for stopping the drive of the motor 2. Can do.

  In the above embodiment, the current command output circuit 61 is configured to output a low-level current command signal when power supply is interrupted. However, the present invention is not limited to this, and power supply is interrupted. In this case, a high level current command signal can be output. Specifically, the current command output circuit 61 includes an I / F circuit that outputs a current command signal.

  The I / F circuit connected to the photocoupler PC1 includes an N channel MOSFET having a source connected to the power supply line L2 and a back gate grounded, and a P having a source connected to the source of the N channel MOSFET and a drain and back gate grounded. It has a channel MOSFET and a diode provided between the source and drain of the P-channel MOSFET. The sources of the N-channel MOSFET and the P-channel MOSFET are connected to the photocoupler PC1. The I / F circuit connected to the photocouplers PC2 and PC3 is similarly configured.

As a result, when an overcurrent occurs in the power supply line L2, the output of the drive signal to which the current is to be supplied is suppressed, so that the current supply to the motor 2 can be more reliably prevented.
In this case, the N-channel MOSFET and the P-channel MOSFET can be configured as, for example, a VHCT (Very High Speed CMOS, TTL Compatible Inputs) type CMOS (Complementary Mental-Oxide Semiconductor).

Thereby, a high-speed response is possible, and in particular, when the power supply to the control board 6 is cut off, the current supply to the motor 2 can be cut off quickly.
Moreover, in the said embodiment, although the fuse 34 was utilized as an overcurrent protection means, not only this but a breaker, an electromagnetic switch, an electromagnetic contactor, and other overcurrent protection apparatuses can also be utilized.

Moreover, in the said embodiment, although comprised using the three-phase motor 2, it is not restricted to this, It can also comprise using a two-phase motor or a motor more than four phases.
In the above embodiment, the alarm signal output device, the load protection device, and the alarm signal output method according to the present invention are applied to the case of controlling the motor 2, but the present invention is not limited to this. The present invention can be applied to other cases without departing from the scope.

It is a block diagram which shows the structure of the motor control apparatus which concerns on this Embodiment. 3 is a block diagram showing a circuit configuration of an alarm circuit 35. FIG. 4 is a time chart showing a change with time of drive current to the motor 2; 3 is a flowchart showing the operation of the alarm circuit 35. It is a time chart which shows a time-dependent change of the output signal of each part. It is a block diagram which shows the structure of the conventional motor control apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1a, 1b Power supply 2 Motor 3, 300 Power amplifier board 6, 600 Control board 31, 310 Signal processing part 32, 320 Power supply part 34 Fuse 35 Alarm circuit 36 Latch circuit 70a-70c Current sensor 71a-71c Filter circuit 72a-72c Integration circuits 73a to 73c, 74a to 74c Comparators 37, 75a, 75b, 76 OR circuit 39 Motor drive circuit 40 Relay 61 Current command output circuit 62 CPU
L1, L2 Power line PC1-PC5 Photocoupler

Claims (5)

An alarm signal output device applied to a load operating device that operates the load by supplying current from a power source to the load,
When an abnormality occurs in the current supplied to the load, an alarm signal output means for outputting an alarm signal to stop the operation of the load, and an alarm signal holding means for holding an alarm signal from the alarm signal output means An alarm signal output device comprising: A power supply board that operates the load by supplying current from a power supply to the load, a control board that operates by receiving power supply from the power supply board and controls the load, and the control from the power supply board Overcurrent protection means provided in a current path for transmitting power to the board, and the control board comprises current command signal output means for outputting a current command signal indicating a command value of current to be supplied to the load. The power supply board outputs an operation signal based on a current command signal from the control board, and an operation signal output means outputs an operation signal to the load based on the operation signal from the operation signal output means. A load protection device comprising a load operating means to supply,
When an abnormality occurs in the current supplied to the load, the power supply board outputs an alarm signal output means for outputting an alarm signal to stop the operation of the load, and an alarm signal from the alarm signal output means. An alarm signal holding means for holding the load protection device. In claim 2,
The load protection device according to claim 1, wherein the power supply board includes a current supply cut-off unit that cuts off a current supply to the load when the alarm signal held by the alarm signal holding unit is input. In any one of Claims 1 thru | or 3,
The control board is connected to the current path through the overcurrent protection means and supplies power to the operating device, an operation signal input terminal for inputting an operation signal from the operating device, and the operation A load protection device comprising: control means for controlling the current command signal output means based on an operation signal input from a signal input terminal. An alarm signal output method applied to a load operating device that operates the load by supplying a current from a power source to the load,
When an abnormality occurs in the current supplied to the load, an alarm signal output step for outputting an alarm signal to stop the operation of the load, and an alarm signal holding for holding the alarm signal output in the alarm signal output step A method for outputting an alarm signal.

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