JP2007295652A - Electric motor driving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To facilitate maintenance by suppressing consumption of a brush of a DC motor in an electric motor driving device for driving a driving object, while switching an AC motor and the DC motor. <P>SOLUTION: Any one of the AC motor 8 drivable on an AC power source 20 and the DC motor 10 drivable on a battery 34 selected by a switch 28 drives an output shaft 2. The commutator 12 and the brush 14 of the DC motor 10 are provided so that any one of them can protrude and shrink for the other, and the commutator 12 and the brush 14 are spaced from each other when the AC motor 8 is driven. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electric motor drive device that drives an output shaft by an electric motor, and more particularly to a device that switches between an AC motor and a DC motor.

  An example of an electric motor driving apparatus that switches between an AC motor and a DC motor as described above is disclosed in Patent Document 1. The technique of Patent Document 1 drives a shutter. When AC power is supplied, the AC motor is rotated by AC power to drive the shutter, and when AC power is not supplied, direct current from the battery is supplied. A direct current motor is rotated by a power source to drive a shutter.

Japanese Utility Model Publication No. 58-19099

  In the technique of Patent Document 1, the shutter is driven by either an AC motor or a DC motor. In a normal state, the shutter is driven by the AC motor. During this time, although the DC motor is not driven, the brush of the DC motor and the commutator are kept in contact with each other, and there is a problem that the brush is worn early. Each time the brush was worn, it had to be replaced, and maintenance for it had to be done frequently.

  It is an object of the present invention to provide an electric motor drive device that operates by switching between an AC motor and a DC motor, which has few consumable parts and can be easily maintained.

  The electric motor driving device of one embodiment of the present invention includes an AC motor that drives an output shaft. An AC power source is connected to the AC motor. The electric motor drive device further includes a DC motor that drives the output shaft, and a DC power source connected to the DC motor. The AC motor and the DC motor may be provided separately from the output shaft, and the rotor of the AC motor and the DC motor may be coupled to the output shaft, or the rotor of the AC motor and the DC motor may be provided on the output shaft. The controller is operated by switching between the AC motor and the DC motor. For example, when the AC power can be supplied to the AC motor, the switching is performed by driving the output shaft by the AC motor. When the AC power cannot be supplied, the DC power is supplied to the DC motor and the output shaft is supplied to the DC motor. Can be made to rotate. A commutator and a brush that can contact the commutator are used for the current from the DC power source to the DC motor. One of the commutator and brush of the DC motor is provided so as to be able to advance and retreat relative to the other. The commutator and the brush are spaced apart when the AC motor is driven.

  According to the electric motor driving apparatus configured as described above, the commutator and the brush of the DC motor are separated from each other while the output shaft is driven by the AC motor. Therefore, the brush can be prevented from being worn while the AC motor is driving the output shaft, and the frequency of brush replacement can be reduced.

  A first AC-DC converter connected to the AC power source can be provided. In this case, the DC power source is a storage battery connected to the first AC-DC converter. In normal times, the output shaft is driven by the AC motor, and in emergency situations, the output shaft is driven by the DC motor.

  If comprised in this way, since a brush contacts a commutator only at the time of emergency, abrasion of a brush can be reduced more.

  Further, a switching unit that monitors the AC power supply and makes the brush and the commutator contact when the AC power supply disappears can be provided. The monitoring of the AC power source can monitor, for example, the voltage or current of the AC power source, or the voltage or current of the AC-DC converter connected to the AC power source.

  If comprised in this way, since a brush contacts with a commutator only when AC power supply lose | disappears, abrasion of a brush can be reduced more.

  Furthermore, a second AC-DC converter connected to the AC power source can be provided. In this case, the switching unit is connected to the second AC-DC converter. The switching unit includes a first relay unit that monitors the AC power supply or the second AC-DC converter, and a solenoid unit that is connected to the second AC-DC converter via the first relay unit. The solenoid unit sucks the brush or the commutator to separate the brush and the commutator. The first relay unit may include a contact disposed between the second AC-DC converter and the solenoid unit, and a drive unit that opens and closes the contact. When the output voltage or current of the second AC-DC converter disappears, the driving unit closes the contact and separates the brush and the commutator from the solenoid unit.

  If comprised in this way, since a brush and a commutator can be spaced apart by the switching part which consists of a relay part and a solenoid part, a structure can be simplified.

  In addition, a second relay unit can be provided between the DC motor and the DC power source. In this case, the second relay unit connects the DC motor and the DC power source when the DC motor is driven. The second relay unit also includes a contact and a drive unit, and this drive unit can be shared with the drive unit of the first relay unit.

  With this configuration, even when the contact and the brush are in contact with each other due to a failure or the like when the output shaft is driven by the AC motor, the DC motor is supplied with a DC power source by the action of the second relay unit. Not supplied. Therefore, the DC motor does not operate, and the drive of the output shaft is continued only by the AC motor.

  In addition, a sensor switch that shuts off the DC motor and the DC power supply when a driven part connected to the output shaft reaches a predetermined position may be provided. There are various types of driven parts, such as a pitch driving device for a rotor of a wind turbine for wind power generation, an electric shutter, and an electric door. In the case of a wind turbine, the predetermined position includes a feathering position of a blade, an open position or a closed position of an electric shutter or an electric door.

  If comprised in this way, a driven part can be driven to a predetermined position and the driven part can be stopped at the time of the emergency which drives a driven part with a direct-current motor.

  In addition, an electromagnetic brake unit that holds the output shaft when power is not supplied can be provided. For example, the rotation of the output shaft can be prevented by the electromagnetic brake unit. In this case, electric power is supplied to the electromagnetic brake unit from the AC power source and the DC power source.

  With this configuration, even if the power supply from the AC power supply to the electromagnetic brake unit is stopped, power is supplied from the DC power supply to the electromagnetic brake unit. There is no stopping.

  Further, the electromagnetic brake unit includes a sensor switch that shuts off the DC motor and the DC power source when electric power is supplied from the AC power source and the driven unit connected to the output shaft is in a predetermined position. Is provided. Power is supplied to the electromagnetic brake unit from between the sensor switch and the DC motor.

  With this configuration, when the AC power source disappears, the output shaft is driven by the DC motor and the DC power source is supplied to the electromagnetic brake unit, so that driving of the driven unit is continued. When the driven part is driven to a predetermined position, the supply of DC power to the electromagnetic brake part is stopped by the sensor switch, the electromagnetic brake part is operated, and the driven part is held at the predetermined position. That is, when the AC power supply disappears, the driven part is driven to a predetermined position and then held at that position.

  As described above, according to the present invention, in an electric motor drive device that drives the output shaft by switching between a DC motor and an AC motor, maintenance of the DC motor brush can be prevented, thereby facilitating maintenance. it can.

  An electric motor drive device according to an embodiment of the present invention is provided in a rotor of a horizontal axis wind power generator, for example, and is used in a pitch drive device that changes the pitch of rotor blades. In this embodiment, the driven part driven by the electric motor driving device is a blade.

  This electric motor drive device has an output shaft 2 as shown in FIG. The output shaft 2 is coupled to the blade via a driving force transmission mechanism (not shown). The output shaft 2 is rotatably supported by the housing 6 via bearings 4 and 4.

  For example, a rotor 8R of an AC motor 8 which is an induction motor is attached to the output shaft 6. The rotor 8R is a cage rotor, for example. A stator 8S of AC motor 8 is arranged so as to surround rotor 8R. The stator 8S is attached to the housing 6. The stator 8S is, for example, a coil.

  Adjacent to the rotor 8 </ b> R of the AC motor 8, the rotor 10 </ b> R of the DC motor 10 is attached to the outer periphery of the output shaft 2. The rotor 10R is, for example, a coil. A stator 10S of the DC motor 10 is arranged so as to surround the periphery of the rotor 10R. The stator 10S is also attached to the housing 6. The stator 10S is a permanent magnet, for example.

  Two commutators 12 that are electrically connected to the rotor 10 </ b> R in order to supply power to the rotor 10 </ b> R of the DC motor 10 are disposed on the outer periphery of the output shaft 2 at intervals. In FIG. 1, only one commutator 12 is shown.

  In order to supply a direct current to the commutators 12, brushes 14 are disposed in the housing 6 so as to face the commutators 12. In general, the brush is always in contact with the commutator, but the brush 14 of this embodiment is configured to selectively take a contact state and a non-contact state with respect to the commutator 12. Therefore, each brush 14 is coupled to a solenoid 16 provided so as to correspond to the brush 14. When a direct current flows through the solenoid 16, the brush 14 is separated from the commutator 12. When the current supply to the solenoid 16 is stopped, the solenoid 16 moves the brush 14 and contacts the commutator 12. That is, the brush 14 can move forward and backward with respect to the commutator 12. These solenoids 16 are accommodated in sleeves 18 respectively provided in the housing 6.

  As shown in FIG. 2, this electric motor drive device supplies a commercial AC current supplied from an AC power supply 20 to an inverter 22. In the inverter 22, the AC voltage of the AC power supply 20 is once converted into a DC voltage, then converted into an AC voltage whose frequency is changed according to a control signal from the controller 24, and supplied to the AC motor 8. The AC motor 8 is operated and stopped by supplying and stopping the converted AC voltage, and the speed of the AC motor 8 is controlled by changing the frequency of the converted AC voltage. In order to control the AC motor 8, a sensor signal from a sensor (not shown) such as a rotary encoder coupled to the output shaft 2 is supplied to the controller 20. The operating power for the controller 24 is also supplied from the AC power source 20.

  An alternating current from the alternating current power supply 20 is supplied to a second alternating current-direct current converter, for example, an AC / DC converter 26, and converted into a direct current. This direct current is supplied to the solenoid 16 via a control unit, for example, a switching unit, specifically, a first relay unit of the relay 28, for example, a relay a contact 28a. The direct current is also supplied to the relay drive unit 28 d of the relay 28. The relay drive unit 28d closes the relay contact 28a when a direct current is supplied from the AC / DC converter 26. Accordingly, whether or not the AC power source 20 generates an AC current is monitored by the relay drive unit 28d, and when the AC current is generated, a DC current is supplied to the solenoid 16, and the brush 14 is connected to the commutator 12. The separated state is maintained, and the DC motor 10 does not rotate.

  Further, the DC current of the AC / DC converter 26 is also supplied to the electromagnetic brake 30 provided in the AC motor 8 via the relay contact 28 a. The electromagnetic brake 30 is of a negative type, and when a direct current is not supplied, performs a braking operation to stop the rotation of the AC motor 8 and prevent further rotation. As a result, the state where the output shaft 2 is also prevented from rotating is maintained. The electromagnetic brake 30 enables the AC motor 8 to rotate without performing a braking operation when a direct current is supplied. As a result, the output shaft 2 can also rotate. Therefore, the electromagnetic brake 30 does not operate when the AC power source 2 generates an AC current. Note that the electromagnetic brake 30 is not shown in FIG.

  The alternating current from the alternating current power supply 20 is supplied to a first alternating current-direct current converter, for example, an AC / DC converter 32, and is converted into a direct current. This direct current is supplied to a storage battery, for example, a battery 34, and the battery 34 is charged. This charging is continued while the AC power supply 20 generates an AC current.

  The direct current from the battery 34 is supplied to the brush 14 of the direct current motor 10 through a second relay unit, for example, a relay contact 28 b of the relay 28 and a series circuit of the sensor switch 36. The relay contact 28b is closed while no current is supplied to the relay drive unit 28d, and is opened while a current is supplied to the relay drive unit 28d. The sensor switch 36 is opened when the blade as the driven portion rotates to a predetermined position, for example, a feathering position, and is closed when the blade is not rotated to the predetermined position.

  Therefore, in a state where an alternating current is output from the alternating current power supply 20 and a current is flowing through the relay drive unit 28d, the relay contact 28b is opened, and no current is supplied to the direct current motor 10 from the battery 34. The motor 10 does not rotate.

  As described above, when the AC power supply 20 is not outputting an AC current, the relay contact 28b is closed. At this time, if the blade has not reached the feathering position, the sensor switch 36 is closed. Therefore, a direct current is supplied from the battery 34 to the direct current motor 10, and the direct current motor 10 rotates. When the blade moves to the feathering position, the sensor switch 36 is opened, the current supply to the DC motor 10 is stopped, the DC motor 10 is stopped, and the movement of the blade is also stopped.

  A connection point between the sensor switch 36 and the DC motor 10 is connected to the electromagnetic brake 30. Therefore, when both the relay contact 28b and the sensor switch 36 are closed, a direct current is also supplied to the electromagnetic brake 30, and the output shaft 2 can rotate.

  In the electric motor driving apparatus configured as described above, the AC / DC converters 26 and 32 generate DC currents in a state where the AC power supply 20 generates AC current. At this time, the battery 34 is charged by the AC / DC converter 32.

  Further, a direct current flows from the AC / DC converter 26 to the relay drive unit 28, and the relay contact 28a is closed. As a result, a current flows through the solenoid 16 and the brush 14 and the commutator 12 are separated from each other. At the same time, the relay drive unit 28d opens the relay contact 28b. Accordingly, direct current from the battery 34 is not supplied to the brush 14. Therefore, the DC motor 10 does not rotate. Thus, since the brush 14 is separated from the commutator 12 and the current supply to the brush 14 is blocked, the DC motor can be used even if the brush 14 is in contact with the commutator 12 due to the failure of the solenoid 16. 10 does not rotate accidentally. The current from the AC / DC converter 26 is supplied to the electromagnetic brake 30 via the relay contact 28a. As a result, the electromagnetic brake 30 is not operating.

  In this state, when an instruction is given from the controller 24 to the inverter 22, the inverter 22 supplies an AC voltage to the AC motor 8, and the AC motor 8 rotates and rotates the blade. During this time, since the commutator 12 and the brush 14 are in a non-contact state, the brush 14 is not consumed. The controller 24 is supplied with a signal from a sensor (not shown) when the relay contact 28b is opened, and the controller 24 operates the AC motor 8 on the inverter 22 on condition that this signal is supplied. Let

  For example, in the event of an emergency such as a power failure, if the AC power supply 20 does not generate an AC current, the AC / DC converters 26 and 32 cannot supply a DC current. As a result, no current flows through the relay drive unit 28d, the relay contact 28a is opened, and the current supply to the solenoid 16 is stopped. As a result, the brush 14 contacts the commutator 12. On the other hand, the relay contact 28b is closed when the current no longer flows through the relay drive unit 28d. At this time, if the blade is not in the feathering position, the sensor switch 36 is closed, and a direct current is supplied from the battery 34 to the electromagnetic brake 30 via the relay contact 28 b and the sensor switch 36. As a result, a direct current continues to flow through the electromagnetic brake 30 and maintains an inoperative state. At the same time, current is supplied from the battery 34 to the brush 14 of the DC motor 10 via the relay contact 28 b and the sensor switch 36. Since the brush 14 and the commutator 12 are in contact, the DC motor 10 starts to rotate.

  When the blade rotates to the feathering position by the rotation of the DC motor 10, the sensor switch 36 is opened, the current supply to the DC motor 10 and the electromagnetic brake 30 is stopped, the DC motor 10 is stopped, and the electromagnetic brake 30 Starts braking. Accordingly, the blade remains stopped at the feathering position.

  When the AC power supply 20 is restored and the generation of the AC voltage is resumed, the AC / DC converters 26 and 32 generate a DC voltage, and a current flows through the solenoid 16 in the same manner as described above, and the brush 14, the commutator 12, Are separated from each other, the brake 30 is deactivated, and the AC motor 8 is rotatable. Further, the relay contact 28 b is opened, and no direct current is supplied from the battery 34 to the brush 14.

  In the above embodiment, the brush 14 is provided so as to be movable back and forth with respect to the commutator 12, but conversely, the commutator 12 can be provided so as to be able to advance and retract relative to the brush 14.

  In the above embodiment, the AC motor 8 and the rotors 8R and 10R of the DC motor 10 are provided on the output shaft 2. For example, the rotor 8R of the AC motor 8 is provided on the output shaft dedicated to the AC motor 8, and the DC motor 10 is provided. The rotor 10R can be provided on the output shaft dedicated to the DC motor 10, the two output shafts can be connected, and the connected one can be connected to the blade. Further, the AC motor 8 may be a servo motor, and the rotor 8R may be a permanent magnet.

  In the above embodiment, the relay drive unit 28d is provided on the output side of the AC / DC converter 26. However, if the relay drive unit 28d is changed to one that operates when an alternating current flows, an AC power supply 20 may be provided on the input side of the AC / DC converter 26 so that an alternating current flows from the AC.

  In the above embodiment, the electromagnetic brake 30 is provided, but may be removed depending on circumstances.

  In the above embodiment, the solenoid 28b is also driven by the relay drive unit 28d to control the current supply to the brush 14. However, the relay contact 28b may be removed depending on circumstances. In the above embodiment, the sensor switch 36 is provided, but may be removed depending on circumstances.

  In the above-described embodiment, the battery 34 is configured to be charged by the AC / DC converter 32. However, when a precharged battery is used, the AC / DC converter 32 can be removed. .

  In the above embodiment, the electric motor drive device according to the present invention is implemented in the pitch drive device of the windmill. However, it may be used as a yaw drive device that rotates the nacelle of the windmill so that the rotor of the windmill faces the front of the wind. it can. Alternatively, the electric motor driving device can also be used to drive the electric shutter and the electric door. In this case, the sensor switch 36 is configured to be opened when the shutter or the door reaches the open position or the closed position.

1 is a partially omitted cross-sectional view of an electric motor drive device according to an embodiment of the present invention. It is a block diagram of the electric motor drive device of FIG.

Explanation of symbols

2 Output shaft 8 AC motor 10 DC motor 12 Commutator 14 Brush 20 AC power supply 24 Controller (control unit)
34 Battery (DC power supply)

Claims (8)

An AC motor that drives the output shaft;
AC power source connected to this AC motor,
A DC motor for driving the output shaft;
A DC power source connected to the DC motor;
A control unit for switching and operating the AC motor and the DC motor,
In the provided electric motor drive device,
One of the commutator and brush of the DC motor is provided so as to be able to advance and retract relative to the other, and the commutator and the brush are separated from each other when the AC motor is driven. The electric motor drive device according to claim 1,
A first AC-DC converter connected to the AC power source;
The storage battery connected to the first AC-DC converter is the DC power source,
An electric motor driving device that drives the output shaft with the AC motor in a normal state and drives the output shaft with the DC motor in an emergency state. In the electric motor drive device according to claim 2,
An electric motor drive device comprising a switching unit that monitors the AC power supply and causes the brush and the commutator to contact when the AC power supply disappears. In the electric motor drive device according to claim 3,
A second AC-DC converter connected to the AC power source;
The switching unit is connected to a second AC-DC converter, a first relay unit that monitors the AC power supply or the second AC-DC converter, and a second AC via the first relay unit. A solenoid unit connected to a DC converter and sucking the brush or commutator to separate the brush and the commutator;
Electric motor drive device provided. In the electric motor drive device according to any one of claims 1 to 4,
An electric motor drive device, wherein a second relay unit is provided between the DC motor and the DC power source, and the second relay unit connects the DC motor and the DC power source when the DC motor is driven. In the electric motor drive device according to any one of claims 2 to 5,
An electric motor drive device provided with a sensor switch that shuts off the DC motor and the DC power supply when a driven part connected to the output shaft reaches a predetermined position. In the electric motor drive device according to any one of claims 2 to 5,
Comprising an electromagnetic brake portion for holding the output shaft when power is not supplied;
The electromagnetic brake unit is an electric motor driving device that supplies electric power to the electromagnetic brake unit from the AC power source and the DC power source. In the electric motor drive device according to claim 7,
The electromagnetic brake unit is supplied with power from the AC power source,
When a driven part connected to the output shaft is in a predetermined position, a sensor switch is provided that shuts off the DC motor and the DC power supply,
An electric motor driving device in which power is supplied to the electromagnetic brake unit from between the sensor switch and the DC motor.

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