JP2010074883A - Drive device of motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drive device of a motor wherein if start fails, restart can be carried out without fail. <P>SOLUTION: A drive circuit 14 built in a motor includes a failure decision circuit that determines whether a failure has occurred. If start fails and it is not determined that it is not a failure, a start wait signal is output to an external control circuit 16. After the passage of a predetermined time, the control circuit 16 carries out restart. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a motor drive device in which a drive circuit is built in a motor.

  A conventional brushless DC motor (hereinafter simply referred to as “motor”) supplies a PWM signal from a logic circuit to an inverter circuit in order to control its rotation speed and start / stop, and a drive current is supplied from the inverter circuit to the brushless DC motor. (See, for example, Patent Document 1).

As shown in FIG. 3, in a sensorless driving method that does not have a Hall IC or the like, a driving device 102 is provided separately from the motor 100. The driving device 102 includes a power unit 104 formed of an inverter circuit and a controller-side microcomputer 106 including a logic unit 108, and the logic unit 108 adjusts the rotation speed of the motor 100. If an abnormality in rotational speed occurs, the microcomputer 106 can determine. Therefore, even in the sensorless driving method, when the motor 100 fails to start, the microcomputer 106 issues a restart instruction.
JP 2006-67647 A

  However, in the drive device 102 shown in FIG. 4, the power unit 104 and the logic unit 108 are built in the housing of the motor 100, and the microcomputer 106 on the controller side is provided separately from the motor 100. The microcomputer 106 outputs a power supply and a speed command signal to the motor 100, and conversely outputs a rotation pulse (that is, a pulse corresponding to the rotation speed) from the logic unit 108 of the motor 100. The microcomputer 106 performs speed feedback control using the speed command signal Vsp and the rotation pulse.

  In the driving device 102 of the motor 100 as described above, when the rotation speed becomes abnormal, the microcomputer 106 detects an abnormality in the output of the rotation pulse of the motor 100. However, in the sensorless driving method, when the activation fails and restarts, it is impossible to determine whether the microcomputer 106 has failed to start due to a disturbance or the like, or cannot be activated due to a failure.

  Therefore, in view of the above problems, the present invention provides a motor drive device that can reliably perform restart when startup fails.

  According to a first aspect of the present invention, there is provided a motor drive device including a drive circuit built in a motor and a control circuit provided separately from the motor, wherein the drive circuit is a three-phase fixed motor. Based on an inverter circuit that rotates a rotor by supplying three-phase drive currents to the child windings, a rotation speed detection circuit that detects the rotation speed of the rotor, and a speed command signal output from the control circuit A logic circuit that supplies a PWM signal to the inverter circuit, a drive voltage detection circuit that detects a drive voltage value supplied to the inverter circuit, and (1) the detected drive voltage value is higher than a first reference value k1. It is determined that there is no failure when it is lower than a second reference value k2 (where k1 <k2) and the detected rotational speed is zero, and (2) the detected drive voltage value is the first reference value. value When the detected drive voltage value is higher than the second reference value, it is determined that there is a failure, and (4) when it is determined that there is no failure, the control circuit A failure determination circuit that outputs a start waiting signal to the control circuit, wherein the control circuit outputs (1) a speed command signal based on the detected rotational speed so that the motor has a predetermined rotational speed. (2) The motor drive device is characterized in that the speed command signal is re-output after a predetermined time from when the start waiting signal is input.

  As described above, according to the present invention, since the control circuit restarts only when the start wait signal is output, the restart can be reliably performed.

  Hereinafter, a driving device 12 for a motor 10 according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2.

(1) Configuration of Motor 10 The motor 10 of the present embodiment is a three-phase brushless DC motor, and is a molded motor in which a housing is formed of a molded resin. In this mold motor, a printed wiring board is attached to a stator, and the printed wiring board and the stator are embedded in a housing formed integrally with the mold resin. A rotor is inserted inside the housing, and the rotor is rotatably fixed via a bearing by a bracket.

(2) Configuration of Drive Device 12 The drive device 12 includes a drive circuit 14 provided on a printed wiring board built in the motor 10 and a control circuit 16 including a microcomputer provided separately from the motor 10. It is configured.

  As shown in FIG. 1, the drive circuit 14 includes an inverter circuit 18 and a logic circuit 20.

  As shown in FIG. 2, the logic circuit 20 includes a logic unit 22, a drive voltage detection unit 24, and a rotation speed detection unit 26.

  The inverter circuit 18 is composed of a full bridge circuit composed of switching elements composed of six FETs, and supplies three-phase drive currents to the three-phase stator windings 28u, v, w of the motor 10, respectively. The inverter circuit 18 is driven by a DC drive voltage supplied from an external control circuit 16. The value of this drive voltage is detected by a drive voltage detector 24 connected to the inverter circuit 18. That is, a current corresponding to the drive voltage is branched from a line on the ground side of the inverter circuit 18 and input to the drive voltage detection unit 24, and the value of the drive voltage is detected from the current corresponding to the drive voltage. The detected drive voltage value is output to the logic unit 22.

  The rotation speed detector 26 detects a three-phase drive current, and detects the rotation speed from the three-phase drive current. The detected rotation speed is output to the logic unit 22.

  The logic unit 22 performs PWM control based on a speed command signal supplied from an external control circuit 16 and outputs a PWM signal to each switching element of the inverter circuit. Each of the switching elements is turned on / off by the output PWM signal, and a three-phase drive current is supplied to the three-phase stator windings 28u, v, w, and the motor 10 rotates. The logic unit 22 outputs a rotation pulse to the control circuit 16 based on the rotation speed supplied from the rotation speed detection unit 26. This rotation pulse is proportional to the rotation speed.

  The control circuit 16 detects the current rotation state of the motor 10 based on the rotation pulse, outputs a speed command signal to the logic unit 22 so as to obtain a predetermined rotation speed, and performs speed feedback control. Yes.

(3) Control Method when Startup Fails Next, a control method when the startup fails when a speed command signal is input from the control circuit 16 and the motor 10 is to be started will be described.

When the activation fails, the logic unit 22 determines whether or not the following condition is satisfied. The first condition is when the drive voltage is lower than the first reference value k1. In this case, it is determined that there is a failure because of the low voltage.

  The second condition is that when the drive voltage is equal to or greater than the second reference value k2 (where k1 <k2), the drive voltage is determined to be a failure due to overvoltage.

  The third condition is determined to be a failure when the three-phase drive current is flowing in the rotational speed detection unit 26 in a short-circuited state. The determination as to whether or not they are short-circuited is made when at least two-phase drive currents of the three-phase drive currents have the same amplitude value and the same phase.

  On the other hand, in other cases, that is, when the drive voltage is higher than the first reference value k1, lower than the second reference value k2, and the three-phase drive current is not short-circuited, and the detected rotational speed is It is determined that there is no failure when it is 0 (that is, in a state where activation has failed).

  Then, the logic unit 22 outputs an activation waiting signal to the control circuit 16 when determining that there is no failure.

  In the control circuit 16, when a start waiting signal is input, a speed command signal is output so as to restart after a predetermined time (for example, 3 minutes). On the other hand, when this activation waiting signal is not input, the control circuit 16 determines that the motor 10 is out of order and transmits it to the user through a lamp, buzzer or the like.

(4) Effect When restarting fails as described above, the logic unit 22 determines whether or not the motor 10 has a failure. If not, a start waiting signal is output to the control circuit 16 and restarted after a predetermined time. Since the start is performed, the motor 10 can be reliably restarted.

  Further, when the activation waiting signal is not input, it can be determined that there is a failure and can be notified to the user.

(5) Modification Examples The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the gist thereof.

  In the above-described embodiment, the printed wiring board is described as a mold motor built in the mold resin. However, instead of this, the housing may be a brushless DC motor made of steel plate.

  A motor other than the brushless DC motor may be used.

It is a block diagram of the drive device of the motor which shows one Embodiment of this invention. It is a block diagram of a drive circuit. It is a block diagram of the drive device of the motor of the 1st conventional example. It is a block diagram of the drive device of the motor of the 2nd prior art example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Motor 12 Drive apparatus 14 Drive circuit 16 Control circuit 18 Inverter circuit 20 Logic circuit 22 Logic part 24 Drive voltage detection part 26 Rotation speed detection part 28u, v, w Stator winding

Claims (4)

In a motor drive device having a drive circuit built in a motor and a control circuit provided separately from the motor,
The drive circuit is
An inverter circuit for rotating a rotor by supplying a three-phase driving current to the three-phase stator windings of the motor;
A rotational speed detection circuit for detecting the rotational speed of the rotor;
A logic circuit for supplying a PWM signal to the inverter circuit based on a speed command signal output from the control circuit;
A drive voltage detection circuit for detecting a drive voltage value supplied to the inverter circuit;
(1) No failure when the detected drive voltage value is higher than the first reference value k1 and lower than the second reference value k2 (where k1 <k2) and the detected rotational speed is zero. (2) When the detected drive voltage value is lower than the first reference value, it is determined that there is a failure. (3) When the detected drive voltage value is higher than the second reference value, the failure is detected. (4) a failure determination circuit that outputs a start waiting signal to the control circuit when it is determined that there is no failure;
Have
The control circuit includes:
(1) A speed command signal is output based on the detected rotational speed to perform speed feedback control so that the motor has a predetermined rotational speed, and (2) a predetermined time from when the start waiting signal is input. The speed command signal is output again later. The motor drive apparatus according to claim 1, wherein the failure determination circuit detects the three-phase drive current and determines a failure when the drive current is short-circuited. The motor driving apparatus according to claim 1, wherein the motor is a molded motor. The motor driving apparatus according to claim 1, wherein the motor is a brushless DC motor.

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