JP2014147244A - Motor driver - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor driver capable of reducing circuit load while ensuring a start-up performance within a motor using a circuit mainly driving a brushless motor.SOLUTION: The motor driver includes: a power unit that supplies a current to a winding of a motor; a control unit that controls the current; and a current detection unit that detects at least one of the current flowing through the circuit or the current flowing on the winding. The current detection unit has a current regulation function to regulate the current which is supplied when a current greater than a current regulation value is detected. The motor driver is configured to linearly increase the current regulation value from the start-up of the motor.

Description

  The present invention particularly relates to a motor driving device built in a motor used for home appliances and the like.

  A motor is a device that rotates with a supplied current, but protection of the device, protection of the circuit that drives the device, and a function to reduce the current are required from the viewpoint of power consumption reduction. In a motor in which the power supply voltage itself is increased slowly or the rotation speed can be adjusted by a command signal, the command signal is changed gently (for example, see Patent Document 1).

International Publication No. 2011/155189

  The problem to be solved by the present invention is to simplify the motor external system by tackling the function that has been performed outside the motor in the motor, and to improve safety by reducing the current by the current limiting function. When a current limit value is set to one or more fixed values, setting a high current limit value increases the starting current and increases the circuit load, and setting a low current limit value provides a sufficient starting torque. Therefore, there is a possibility that the reliability of starting the motor is impaired, and there is a problem that it is difficult to reduce the circuit load and ensure the starting reliability.

  In order to solve the above-mentioned problems, the present invention is characterized in that the circuit load is reduced without deteriorating the reliability of starting the motor by increasing the current limit value from a low value at the time of starting. As a result, energy can be saved, noise and vibration at the time of startup can be reduced, and the noise can be reduced.

  According to the present invention, it is possible to contribute to energy saving by reducing the circuit load while ensuring the startability, and there is an effect that the required performance of the circuit components can be reviewed and the cost can be reduced. In addition, by gradually increasing the startup, there is an effect of reducing noise and vibration at startup and contributing to noise reduction.

  According to the second aspect of the invention, the current limit value does not increase beyond a certain value, and is set according to the performance of the power section, so that it is safe against excessive current generated due to load fluctuation during rotation. The same effect as described above can be obtained while further improving the properties.

  According to the third aspect of the invention, the current limit value can be set to the minimum value necessary for starting the motor, and the safety can be further improved against excessive current generated due to load fluctuation during rotation. However, the same effect as described above can be obtained.

1 is an external view of a brushless DC motor equipped with a motor drive device according to an embodiment of the present invention. Cross section of the brushless DC motor Schematic of the motor drive device of the embodiment of the present invention Diagram showing current limit value at startup

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is an external view of a brushless DC motor with a built-in motor driving device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the brushless DC motor.

  In this figure, in this brushless DC motor 1, the stator assembly 3 is covered with a lid-like frame 4, and the shaft 5 protrudes. The lead wire 2 for input / output extends from the side surface of the stator assembly 3.

  In the stator assembly 3, a winding 7 is wound around a stator core 8 in which electromagnetic steel plates are laminated, and the whole is held. One end of the stator assembly 3 is covered with a frame 4. A bearing 9 is held at the center of the frame 4 and the other end of the stator assembly 3.

  On the other hand, the rotor assembly 14 has a configuration in which the shaft 5 and the permanent magnet 10 are integrated, and is rotatably supported by the bearing 9. The permanent magnet 10 is opposed to the inner peripheral portion of the stator core 8 via a predetermined gap.

  The brushless DC motor 1 includes a motor driving device 6 for supplying current to at least the winding 7. The motor driving device 6 is fixed to the stator assembly 3 and connected to the end of the winding 7.

  FIG. 3 is a schematic view of the motor driving device 6. The motor driving device 6 detects at least one of a power unit 11 for supplying a current to the winding 7, a control unit 12 for adjusting the current, and a current flowing through the motor driving device 6 or a current flowing through the winding 7. A current detection unit 13 and at least one of the power unit 11, the control unit 12, and the current detection unit 13 are provided with lead wires 2 that perform input / output.

  FIG. 4 shows the current limit value 15 included in the motor driving device 6. When the motor drive device 6 starts energizing the winding 7 to rotate the motor at the point a, the current limit value 15 starts to increase from the initial value, and the winding current increases accordingly, starting the point b. When the necessary winding current is reached, the motor starts rotating. Therefore, it is possible to realize a function that does not unnecessarily supply an excessive current and does not impair the startability.

  FIG. 4 shows an example in which the current limit value is continuously increased even after the motor is started at the point b. However, the current limit value at the point b may be held thereafter. In general, since the motor requires a larger current at the time of startup than at the time of steady rotation, the current limit value can be reduced after the point b. Obviously, even if the current limit value is increased after point b, steady operation is not affected.

  According to the motor driving device of the present invention, it is possible to achieve a reduction in the starting current inside the motor, and it is possible to contribute to energy saving by reducing the circuit load while ensuring the startability. Applicable.

DESCRIPTION OF SYMBOLS 1 Brushless DC motor 2 Lead wire 3 Stator assembly 4 Frame 5 Shaft 6 Motor drive device 7 Winding 8 Stator core 9 Bearing 10 Permanent magnet 11 Power part 12 Control part 13 Current detection part 14 Rotor assembly 15 Current limit value

Claims (3)

A motor drive device having a power unit for supplying current to a motor winding, a control unit for adjusting the current, and a current detection unit for detecting at least one of currents flowing in a circuit or a winding, The current detection unit has a current limiting function for limiting a current supplied when a current equal to or greater than a current limit value is detected, and the current limit value increases linearly from the start of the motor. A motor drive device. 2. The motor drive device according to claim 1, wherein the current limit value is increased, and when the predetermined current limit value or a predetermined time is reached, the current limit value is not further increased. . 3. The motor driving apparatus according to claim 2, wherein the predetermined current limit value or the predetermined time is set as a current limit value or a time when the motor becomes equal to or higher than a certain number of revolutions.