JP2002318601A - Double redundant driver circuit - Google Patents

Abstract

(57) [Problem] To prevent a motor drive current from flowing from an operation side system to a standby side system even when a relay connecting each driver circuit to a motor is stuck due to a failure. Thus, a double redundant driver circuit capable of providing highly reliable full double redundancy is provided. SOLUTION: A main driver circuit 2 and a sub driver circuit 4 for selecting and driving a single motor coil 1 among a plurality of motor coils, a main relay 6 connecting the main driver circuit and the motor coil, and And a slave relay 8 for connecting the slave driver circuit and the motor coil, and the power supplies of the main driver circuit 2 and the slave driver circuit 4 are exclusively turned on.
/ OFF, corresponding to this, the main relay 6 and the sub relay 8
In the dual redundant driver circuit, which is also turned ON / OFF exclusively, a power supply bypass line 10 for supplying a current from the power supply ON driver circuit to the power supply OFF driver circuit and pulling up the potential of the power supply OFF power supply line is provided. Prepare.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dual redundant driver circuit for preventing a motor drive current from flowing from an operating system to a standby system.

[0002]

2. Description of the Related Art FIG. 3 shows a situation in which an experimental device is exchanged for an outboard experiment platform (exposure unit) in the Japan Module (JEM) of the International Space Station under development. Attachment / detachment of the payload such as the experimental apparatus is performed by an apparatus exchange mechanism (EEU) shown in FIG.

[0003] A driver unit (EDU) for driving an equipment exchange mechanism (EEU) receives a command from a control unit (ESC) of an outboard experimental platform (exposure unit) and receives an instruction from the EEU.
The stepping motor mounted on U is driven. Also, the position of the arm of the EEU and the status of attaching / detaching the payload are monitored and transmitted to the ESC.

As a driver for driving each stepping motor mounted on the EEU, a circuit illustrated in FIG. 5 can be considered. This circuit is a single-system driver circuit in which a driver and a motor have a one-to-one correspondence. Each motor coil of a bipolar constant current drive type stepping motor is driven by four switching circuits a, b, c, and d. Each switching circuit is composed of a bipolar transistor (pnp or npn) and a diode, and is configured to conduct between the emitter E and the collector C by the voltage of the base B.

That is, in this figure, the switching circuit b
When the switching circuits a and d are turned off and the switching circuits a and d are turned off, the current flows in the order of power supply → switching circuit b → motor coil → switching circuit c → GND1, and the stepping motor rotates (for example, forward rotation). Conversely, switching circuits a and d are turned on, and switching circuits b and c are
When FF is performed, a current flows in the order of power supply → switching circuit a → motor coil → switching circuit d → GND1, and the stepping motor reversely rotates. Therefore, the forward / reverse rotation of the stepping motor can be controlled by ON / OFF control of the four switching circuits a, b, c, d.

In FIG. 5, reference numeral e denotes a pump circuit which suppresses the generation of a surge voltage when the switch is turned off, and recovers the energy to quickly start a current in the motor when the switch is turned on. Sometimes, it has a role of recovering the motor coil energy at the time of switch-off and suppressing the action of excessive voltage, and ensuring that the voltage of the power supply line is set to 0 at the time of power-off. Such a driver circuit is generally used as a driver for a stepping motor.

[0007]

The outage due to the failure of the space station electronics has a significant effect on the operation of the outboard experimental platform. Therefore, high reliability is also required for the driver circuit of the above-described stepping motor. In order to satisfy this demand, two driver circuits are provided for each phase of each stepping motor, and two driver circuits are connected to the motor by a hard wire OR as illustrated in FIG. Conceivable.

However, in the double redundant driver circuit using the hard wire OR, if one of the relays (f in the figure) for connecting each driver circuit to the motor is fixed due to a failure, the contact is connected via the fixed relay f. Current flows from the driver circuit of the normal operation side system (right side in the figure) to the failed standby side system (left side) as shown by the broken line arrow in the figure, and the current to flow from the operation side system to the motor coil is sufficient. And the motor does not operate normally. In other words, there is a disadvantage that the double driver circuit, which should be provided as a measure against failure, does not operate normally even when the system is switched due to the failure of one of the driver circuits.

The present invention has been made to solve such a problem. That is, an object of the present invention is to prevent the motor drive current from flowing from the operation side system to the standby side system even when the relay connecting each driver circuit to the motor is stuck due to a failure, whereby Another object of the present invention is to provide a double redundant driver circuit capable of providing highly reliable full double redundancy.

[0010]

According to the present invention, a main driver circuit (2) and a sub driver circuit (4) for selecting and driving a single motor coil (1) from a plurality of motor coils. And a main relay (6) connecting the main driver circuit and the motor coil; and a sub relay (8) connecting the sub driver circuit and the motor coil. The main driver circuit (2) and the sub driver In a dual redundant driver circuit, the power supply of the circuit (4) is exclusively turned ON / OFF and the main relay (6) and the slave relay (8) are also exclusively ON / OFF correspondingly. A dual redundant driver circuit is provided, comprising: a power supply bypass line (10) for supplying a current from the ON driver circuit to the power OFF driver circuit to pull up the potential of the power OFF power line. It is.

According to the configuration of the present invention described above, when one of the redundant driver circuits (2, 4) loses its function, the function is stopped by switching the operation system / standby system. This can be prevented beforehand, and the reliability of the driver circuit can be greatly increased. In addition, even when the cause of the loss of function is a contact failure of the relay for selecting the motor, the power supply potential of the standby driver is charged through the power supply bypass line (10) to prevent the current from flowing into the standby system, Power supply to the motor can be maintained.
That is, since the potential of the standby driver becomes equal to the power supply potential of the operation driver, it is possible to prevent the motor drive current from flowing from the operation system to the standby system,
All of the operation side driver output current flows into the motor, and the normal operation of the motor can be maintained.

According to a preferred embodiment of the present invention, the main driver circuit (2) and the subordinate driver circuit (4) each include a power supply line (11) for receiving a current through a diode (11a) and a power supply line (11). Two switching circuits (12, 13) connected in parallel, two switching circuits (14, 15) connected in series to the switching circuits, and a first ground line (16) respectively grounding the switching circuits. A resistor (17) and a capacitor (18) connected in parallel to the power supply line;
And a second ground line (19) for grounding the resistor and the capacitor.

With this configuration, the switching circuit 12,
The forward / reverse rotation of the stepping motor 1 can be controlled by ON / OFF control of 13, 14, and 15, and the drive current to the motor can be quickly reduced by a pump circuit including a resistor (17) and a capacitor (18). Can be stabilized.

The power supply bypass line (10)
Is a first power supply bypass for flowing a current from the power supply line (11) of the main driver circuit (2) to the downstream side of the diode (11a) of the power supply line of the slave driver circuit (4) through the resistor (22a) and the diode (22b). Line (10a)
And a second power supply bypass for flowing current from the power supply line (11) of the slave driver circuit (2) to the downstream side of the diode (11a) of the power supply line of the main driver circuit (4) through the resistor (22a) and the diode (22b). Line (10b)
And consisting of

With this configuration, when the power supply of the main driver circuit (2) is ON and the power supply of the subordinate driver circuit (4) is OFF, the subordinate driver circuit (4) is connected via the first power supply bypass line (10a). The potential of the power supply line can be pulled up. Conversely, when the power supply of the slave driver circuit (4) is ON and the power supply of the main driver circuit (2) is OFF, the power supply line of the main driver circuit (2) is connected via the second power supply bypass line (10b). Can be pulled up.

[0016]

Preferred embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a configuration diagram of an EDU provided with the dual redundant driver circuit of the present invention. Driver unit (EDU) that drives the device exchange mechanism (EEU)
Is expected to operate for more than 10 years. for that reason,
The EDU has a double redundant design as a whole. In order to prevent a failure from spreading, the EDU stops the power supply of the main system and starts the power supply of the sub system when the motor function of the main system fails.
The main / slave motor drive output is connected to the EEU motor by a wired OR, but when the main system fails, the drive capability of the slave system must not be affected.

FIG. 2 is a circuit diagram of the dual redundant driver circuit of the present invention. As shown in the figure, the dual redundant driver circuit of the present invention connects a main driver circuit 2 and a subordinate driver circuit 4 for driving a single motor coil 1 with the main driver circuit 2 and the motor coil 1. Main relay 6
A slave relay 8 for connecting the slave driver circuit 4 and the motor coil 1 is provided.

Main driver circuit 2 and slave driver circuit 4
Are the power supply line 11 and the switching circuit 1 respectively.
2, 13 and 14, 15; first ground line 16, resistor 1
7 and a capacitor 18 and a second earth line 19.

The power supply line 11 receives current through a diode 11a. In order to prevent the failure from spreading, the power supply of the power supply line 11 stops the power supply of the main system and activates the power supply of the sub system when the motor function of the main system fails. That is, the main driver circuit 2 and the sub driver circuit 4
Are exclusively turned on / off. The voltage at power ON is 28 V in this example, and at power OFF,
It is grounded and becomes OV.

The two switching circuits 12 and 13 are connected in parallel to the power supply line 11 and are mutually exclusive ON / O.
FF is performed. Also, two switching circuits 14, 15
Are connected in series to the switching circuits 12 and 13, respectively, and the switching circuits 12 and 15 and 13 and 14 are turned ON / OFF correspondingly. The first ground line 16 is
The emitters E of the switching circuits 14 and 15 are grounded.

The main relay 6 connects two points (between 12 and 14 and between 13 and 15) between the switching circuits of the main driver circuit 2 and both ends of the motor coil 1. Similarly, the slave relay 8 has two points (1) between the switching circuits of the slave driver circuit 4.
2 and 14 and between 13 and 15) and both ends of the motor coil 1. The main relay 6 and the slave relay 8
Are exclusively turned on / off in accordance with the exclusive on / off of the power supply of the main driver circuit 2 and the slave driver circuit 4.

With this configuration, when the switching circuits 12 and 15 are ON, an upward current flows through the coil as shown in FIG.
Conversely, when the switching circuits 13 and 14 are ON, a downward current flows through the coil in the figure. Therefore, the forward / reverse rotation of the stepping motor 1 can be controlled by ON / OFF control of the four switching circuits 12, 13, 14, 15.

In FIG. 1, a resistor 17 and a capacitor 18 are connected in parallel to the power supply line 11. Further, the second earth line 19 connects the resistance and the capacitor to ground. With this configuration, when the power is turned on, the motor coil energy at the time of switch-off is recovered, and the operation of an excessive voltage is suppressed. When the power is turned off, the voltage of the power line can be reliably reduced to zero.

The dual redundant driver circuit of the present invention further comprises:
A power supply bypass line is provided for supplying a current from a power-on driver circuit to a power-off driver circuit to pull up a potential of the power-off power supply line. In this example, the power supply bypass line 10 includes a first power supply bypass line 10a and a second power supply bypass line 10b.

The first power supply bypass line 10a allows current to flow from the power supply line 11 of the main driver circuit 2 to the downstream side of the diode 11a of the power supply line of the slave driver circuit 4 through the resistor 22a and the diode 22b.
Therefore, even when the power supply of the slave driver circuit 4 is OFF,
A current flows from the power supply line 11 of the main driver circuit 2 to the subordinate driver circuit 4 side, and the potential on the downstream side of the diode 11a is pulled up. Similarly, the second power supply bypass line 10b allows a current to flow from the power supply line 11 of the slave driver circuit 2 to the downstream side of the diode 11a of the power supply line of the main driver circuit 4 through the resistor 22a and the diode 22b. Is turned off, the current flows from the power supply line 11 of the slave driver circuit 4 to the main driver circuit 2 side, and the potential on the downstream side of the diode 11a is pulled up. The potential on the standby side at the time of this pull-up matches the power supply voltage (28 V) after the charging of the capacitor 18 is completed.

According to the above-described configuration of the present invention, when one of the redundant driver circuits 2 and 4 loses its function, the operational system / standby system is switched, so that the function is stopped beforehand. Thus, the reliability of the driver circuit can be greatly improved. Further, even when the cause of the loss of function is a contact failure of the relay (6 or 8) for selecting the motor, the power supply potential of the standby driver is pulled up by charging through the power supply bypass line 10 to the standby system. Can be prevented from sneaking around the current, and energization to the motor can be maintained. That is, the potential of the standby driver becomes equal to the power supply potential of the operation driver,
It is possible to prevent the motor drive current from flowing from the operation side system to the standby side system, and all of the operation side driver output current flows into the motor, so that normal operation of the motor can be maintained.

It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified without departing from the gist of the present invention.

[0028]

As described above, the dual redundant driver circuit of the present invention can be used to drive the motor from the operation side system to the standby side system even when the relay connecting each driver circuit to the motor is stuck due to a failure. It is possible to prevent the current from sneaking around, thereby providing excellent effects such as providing highly reliable full-duplex redundancy.

[Brief description of the drawings]

FIG. 1 shows an EDU with a dual redundant driver circuit of the present invention.
It is a block diagram.

FIG. 2 is a circuit diagram of a dual redundant driver circuit of the present invention.

Fig. 3 Japan Module of the International Space Station (JE)
It is a figure which shows the exchange state of the experimental device to the outboard experiment platform (exposure part) in M).

FIG. 4 is a configuration diagram of an apparatus exchange mechanism (EEU).

FIG. 5 is an example of a driver circuit for driving a stepping motor.

6 is a circuit diagram of a double redundant driver circuit obtained by making the circuit of FIG. 5 redundant.

[Explanation of symbols]

Reference Signs List 1 motor coil, 2 main driver circuit, 4 slave driver circuit, 6 main relay, 8 slave relay, 10 power supply bypass line, 10a first power supply bypass line, 10b
Second power supply bypass line, 11 power supply line, 11a
Diode, 12-15 Switching circuit, 16
1st ground line, 17 resistor, 18 capacitor, 1
9 2nd earth line, 22a resistance, 22b diode

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H007 AA06 AA17 BB06 CA01 CB04 CB05 CC03 DB07 FA13 5H209 AA09 DD04 EE01 GG13 JJ01 SS01 SS04 SS08 TT01

Claims (3)

[Claims] A main driver circuit and a sub driver circuit for selecting and driving a single motor coil among a plurality of motor coils; a main driver circuit and the motor coil; And a slave relay (8) connecting the slave driver circuit and the motor coil. The power sources of the master driver circuit (2) and the slave driver circuit (4) are exclusive. In the dual redundant driver circuit, the main relay (6) and the slave relay (8) are exclusively turned on / off in response to this, the driver circuit from the power-on driver circuit to the power-off driver circuit A dual redundancy driver circuit, comprising: a power supply bypass line (10) for supplying a current to the power supply line and pulling up a potential of a power supply line that is turned off. 2. The main driver circuit (2) and the slave driver circuit (4) each include a power supply line (11) for receiving a current through a diode (11a) and two switching circuits connected in parallel to the power supply line. (12,
13), two switching circuits (14, 15) respectively connected in series to the switching circuits, and a first ground line (1) for grounding the switching circuits.
6) and a resistor (17) connected in parallel to the power supply line
2. The dual redundant driver circuit according to claim 1, comprising a second ground line connecting the resistor and the capacitor to a ground. 4. 3. The power supply bypass line (10) is connected from a power supply line (11) of a main driver circuit (2) to a resistor (2).
2a) and a first power supply bypass line (10a) through which current flows downstream of the diode (11a) of the power supply line of the slave driver circuit (4) through the diode (22b); and a power supply line (11) of the slave driver circuit (2). ) Through a resistor (22a) and a diode (22b) to a second power supply bypass line (10b) for passing a current downstream of the diode (11a) of the power supply line of the main driver circuit (4);
3. The double redundant driver circuit according to claim 2, comprising: