JP6056005B2 - Motor control device - Google Patents

Description

  The present invention relates to a motor control device that controls a brushless motor.

Conventionally, in order to efficiently control a brushless motor from low speed to high speed, inverter control of a brushless motor provided with a position detector is often used.
(For example, refer to Patent Document 1).

  FIG. 7 shows a motor control device for driving a general brushless motor, and its configuration will be described below.

  A brushless motor 9, position detectors 3a, 3b, and 3c for detecting the rotor position of the brushless motor, an inverter 11 for driving the brushless motor, and an inverter for driving the brushless motor using a signal of the position detector The control circuit 4 and the drive circuit 62 for controlling the above are included. The brushless motor 2 has a built-in position detector. For example, a Hall IC that outputs the direction of the magnetic flux of the magnet of the rotor as a signal is generally used. The inverter 11 is supplied with a voltage obtained by rectifying the AC power supply 53 with the diode bridge 54 and smoothing with the capacitors Ca and Cb. The inverter is constituted by six switching elements SWU, SWV, SWW, SWX, SWY, SWZ and six diodes 60a, 60b, 60c, 61a, 61b, 61c.

  The motor is controlled by using signals from position detectors 3a, 3b and 3c incorporated in the brushless motor 2, and the control circuit 4 detects the speed and position of the brushless motor from the signals and drives the switching elements of the inverter. The motor is controlled by generating a PWM signal, amplifying and converting the voltage to a voltage that can drive the switching elements SWU, SWV, SWW, SWX, SWY, and SWZ by the drive circuit 62 and driving the inverter.

  By the way, when trying to detect the magnetic flux of the rotor of the brushless motor by using, for example, a Hall IC for the position detectors 3a, 3b, 3c built in the brushless motor 2, the accuracy of mounting the Hall IC, for example, a printed wiring board The position detector output signal is affected by the position accuracy of mounting on the brush, the position accuracy of fixing the printed wiring board to the brushless motor, the mechanical accuracy of the brushless motor rotor, the accuracy of magnetization, etc. A phase shift occurs with respect to the position, that is, the position of the position detector signal relative to the induced voltage of the rotor. This deviation can often be as great as 10 degrees in electrical angle.

  The deviation of the position detector signal, that is, the detected value of the position of the rotor of the brushless motor causes a decrease in efficiency when the brushless motor is driven, and increases the heat generation of the motor. In addition, this tendency increases as the rotation speed of the brushless motor increases. In particular, the induced voltage of the motor cannot be ignored with respect to the power supply voltage, and becomes noticeable when the advance angle control is performed.

  In order to prevent this, a sine wave voltage having a preset voltage and frequency is supplied to the brushless motor 2 and driven in an open loop, and the phase of the sine wave voltage and the phase of the output signal of the position detector are calculated. The amount of deviation is detected and stored in the storage means 5, and when the brushless motor 2 is driven by performing feedback control based on the position signal output from the position detector, it is supplied to the brushless motor 2 based on the amount of deviation. By correcting the sinusoidal voltage to be corrected, the position detector is less affected by the deviation.

JP 2002-325480 A

  However, in such a conventional motor control device, the difference between the phase of the voltage on the sine wave generated when the brushless motor is driven in open loop and the output signal of the position detector is used for storing and controlling. It does not measure the relationship of the position detector signal to the actual motor induced voltage. Therefore, although it is possible to correct the phase difference of the signal with respect to the induced voltage of the position detector to some extent, it is difficult to cope with variations in load when detecting the phase difference of the signal of the position detector. Further, when vector control is performed on a motor from a low speed to a high speed, the influence on the control of the reactive current is great particularly when the advance angle control is performed at a high speed, which may affect the controllability.

  The present invention solves the above-described conventional problems, and in a brushless motor control device, has a highly accurate detection position correction function of a position detector of a brushless motor, and drives the brushless motor efficiently from low speed to high speed. The object is to provide a control device.

  In order to achieve the above object, the present invention provides a brushless motor, a position detector that detects a rotor position of the brushless motor, an inverter that drives the brushless motor, and an output signal of the position detector based on the output signal of the position detector. A control circuit for controlling the inverter that drives the control circuit, and storage means associated with the control circuit, the control means applying a three-phase AC voltage to the winding of the brushless motor, and winding the brushless motor. Rotate the three-phase AC voltage applied to the wire, detect the direction of the three-phase AC voltage when the output signal of the position detector changes, and detect the detected value of the direction of the three-phase AC voltage as the position of the brushless motor The correction value of the detection signal is stored in the storage means, and the output signal of the position detector and the correction value of the position detection signal are used during the operation of the brushless motor. A motor controller for controlling the brushless motor Te.

  As a result, even when the position detector signal with respect to the induced voltage has a deviation with respect to the position where the signal is originally desired, the deviation amount can be accurately corrected.

  The motor control device of the present invention has a highly accurate detection position correction function of the position detector of the brushless motor, and can realize a control device that drives the brushless motor efficiently from low speed to high speed.

Configuration diagram of motor control device of the present invention The figure which shows the relationship between the induced voltage of a brushless motor and a position detection signal Ideal case diagram of line induced voltage and position detector signal Diagram when the line-to-line induced voltage and the position detector signal are shifted The other figure when the signal between line induced voltage and position detector is accompanied Illustration of brushless motor model Side sectional view of a conventional washing machine

  According to a first aspect of the present invention, there is provided a brushless motor, a position detector that detects a rotor position of the brushless motor, an inverter that drives the brushless motor, and an inverter that drives the brushless motor based on an output signal of the position detector. A control circuit for performing control, and storage means associated with the control circuit, wherein the control means applies a three-phase AC voltage to the winding of the brushless motor and applies it to the winding of the brushless motor. Rotate the phase AC voltage, detect the direction of the three-phase AC voltage when the output signal of the position detector changes, and detect the detected value of the direction of the three-phase AC voltage as the correction value of the position detection signal of the brushless motor Is stored in the storage means, and the brushless motor is operated using the output signal of the position detector and the correction value of the position detection signal during operation of the brushless motor. By performing a trial run for correcting the position detection signal in advance, the position detection signal that is the output of the position detector mounted on the brushless motor can be corrected accurately, and the efficiency is low to high. It is possible to realize a control device that drives a brushless motor well.

According to a second invention, in the first invention, the brushless motor is rotated clockwise and counterclockwise, and the direction of the three-phase AC voltage when the output signal of the position detector changes in each rotation direction is detected. By storing the average value of the detected values in the direction of the three-phase AC voltage in the storage means as the correction value of the position detection signal of the brushless motor, it is difficult to be affected by the friction of the shaft or load of the brushless motor. In addition, the position detection signal that is the output of the position detector mounted on the brushless motor can be accurately corrected, and a motor control device that efficiently drives the brushless motor from low speed to high speed can be realized.
According to a third invention, in the first invention, the direction of the three-phase AC voltage to be detected is the same as the number of pole pairs of the brushless motor, and the average value of the detected values in the direction of the three-phase AC voltage is the brushless motor. By storing the position detection signal as a correction value in the storage means, the position detection signal is less affected by variations in the position detection signal for each pole pair of the brushless motor, and is output from the position detector mounted on the brushless motor. It is possible to realize a motor control device that can accurately correct a signal and efficiently drive a brushless motor from a low speed to a high speed.

  According to a fourth aspect of the present invention, in any one of the first to third aspects, the position detection signal correction value is not detected with respect to the rotational speed of the three-phase AC voltage in the vicinity where the position detection signal correction value is detected. By increasing the rotational speed of the three-phase AC voltage in the range, it is possible to shorten the time required for correcting the position detection signal in advance.

  According to a fifth invention, in any one of the first to fourth inventions, the storage means is a non-volatile memory, so that the correction value of the position detection signal is stored even when the control device of the brushless motor is turned off. Therefore, it is possible to realize a motor control device that efficiently drives a brushless motor from low speed to high speed without performing a trial run again when the power is turned on again.

  In a sixth aspect of the present invention, the motor control device according to any one of the first to fifth aspects of the present invention is installed in a washing machine or a washing / drying machine so that the brushless motor is driven at a low speed during washing or drying, and is dehydrated at a high speed. The brushless motor can be driven efficiently until time, and an efficient washing machine or washing / drying machine can be realized.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the thing of the same structure as a prior art example attaches | subjects the same code | symbol, and abbreviate | omits description. Further, the present invention is not limited by this embodiment.

(Embodiment 1)
FIG. 1 is a configuration diagram of a motor control device according to Embodiment 1 of the present invention. The inverter 11 for driving the brushless motor 2 includes switching elements SWU and SWX, SWV and SWY, two sets connected in series of SWW and SWZ, three sets in parallel, and a total of six switching elements. In FIG. 1, an IGBT is used as a switching element as an example. A connection point of a set of two switching elements, for example, the lower side (emitter side) of SWU and the upper side (collector side) of SWX are connected, and the connection point is connected to the winding of brushless motor 2. A position detector 3 is mounted on the brushless motor 2. The output signal CS is input to a control circuit 1 constituted by a microcomputer or the like and used for motor speed control, torque control, and the like. FIG. 1 is an example of the embodiment, and a switching element such as a MOSFET or a bipolar transistor can be used as a switching element to be used.

  FIG. 2 is a diagram showing a signal relationship between the induced voltage of the brushless motor and the position detector. The windings of the brushless motor are U phase, V phase, and W phase. When the rotor of the brushless motor is rotated from the outside, the induced voltage generated at the U-phase winding terminal from the neutral point is generated at Eu, the induced voltage generated at the V-phase winding is generated at the Ev, W-phase winding. The voltage to be performed is Ew. In general, the neutral point often does not appear as a terminal outside the brushless motor, and is often represented by a line voltage. The induced electricity generated at the U-phase winding terminal with respect to the W-phase winding terminal is Euw, the induced electricity generated at the V-phase winding terminal with respect to the u-phase winding terminal as Evu, and the V-phase winding terminal with Ewv is the induced electricity generated at the W-phase winding terminal as a reference. As for the output signal of a position detector, it is common that three lines are output in a three-phase brushless motor.

  CS1, CS2, and CS3 shown in FIG. 2 are examples of the output signal of the position detector. CS1 is synchronized with the above-described line-induced voltage Euw, CS2 is the line-induced voltage Evu, and CS3 is synchronized with the line-induced voltage Ewv. That is, a signal whose logic changes when each line-induced voltage is 0 V (zero volt). In FIG. 2, the signal of the position detector is synchronized with the induced voltage between the lines, but it may be a signal synchronized with Eu, Ev, Ew that is the induced voltage of each phase.

  In general, the position detector detects the magnetic flux of the magnet of the rotor of the brushless motor or the magnetic flux of the magnet for position detection mounted coaxially with the rotor by a Hall element or a Hall IC. At this time, there are variations such as magnetization accuracy, mounting accuracy of the Hall element or Hall IC to the printed wiring board, accuracy of mounting the printed wiring board inside the motor, and detection sensitivity of the magnetic flux of the Hall element or Hall IC. A description will be given using the line induced voltage Euw of the brushless motor described with reference to FIG. 2 and CS1 which is one of the output signals of the position detector.

  FIG. 3 is an example of an ideal case diagram of the line induced voltage and the signal of the position detector. The position detection signal CS1 is synchronized with the line induced voltage Euw. That is, the logic of the position detection signal CS1 changes at a position where the line-to-line induced voltage is 0 V (zero volt) and zero crossing. 4 and 5 are examples of diagrams in the case where the line induced voltage and the position detector signal are shifted. FIG. 4 shows an example in which the position detection signal CS1 advances with respect to the line induced voltage Euw, and FIG. 5 shows an example with a delay.

  The rotor position of the motor when controlling the brushless motor is obtained by interpolating and calculating the rotor position for each control period using the signals CS1, CS2 and CS3 which are the outputs of the position detector. For this reason, if there is a deviation in the position detection signal as described above, the output current waveform is distorted and the phase of the current advances or delays with respect to the position of the rotor of the brushless motor, which adversely affects efficiency and noise. Further, the advance angle control is performed when the induced voltage of the brushless motor becomes relatively high with respect to the power supply voltage. In this case, there is a possibility that the performance may be adversely affected by the shift of the position detection signal. Hereinafter, a method of correcting the detection position of the position detector will be described.

FIG. 6 shows a model of a brushless motor. Further, the relationship between the induced voltage when the brushless motor of FIG. 6 is rotated clockwise and the output signal of the position detector is described with reference to FIG. FIG. 6 shows a two-pole model for ease of explanation. In the two-pole model, the electrical angle and the mechanical angle are the same value. The stator has three windings: a U-phase winding U, a V-phase winding V, and a W-phase winding W.

  A magnet is arranged on the rotor. Consider the coordinates of the angle θ in the clockwise direction with the direction of the U phase of the winding as the origin. The magnetic pole inside the stator that is generated when a positive voltage is applied to the winding of each stator is defined as N pole. Now, the direction of the combined magnetic flux generated by each winding of the stator when a three-phase AC voltage is applied to each winding is defined as the direction of the angle θ. The N pole is generated in the positive direction of the a-axis and the S pole is generated in the negative direction of the a-axis in the stator of FIG. The rotor of the brushless motor is attracted in the direction of the S pole in the positive direction of the a-axis and the N pole in the negative direction due to the attraction and repulsion action with the magnetic pole of the stator.

  When the angle θ is slowly rotated in this state, the rotor of the brushless motor also rotates slowly while maintaining the S pole in the positive direction of the a-axis and the N pole in the negative direction. When the angle θ is rotated, the output signal of the position detector also changes with the rotation of the rotor of the brushless motor. A difference between the position of the angle θ when the output signal of the position detector is changed and the original position is stored as a correction value. When detecting the correction value of the position detection signal of the brushless motor, a three-phase AC voltage is applied to the winding of the brushless motor, and the change point of the signal of the position detector is detected by slowly rotating the angle θ. Hereinafter, details of an example of application of a three-phase AC voltage during detection and details of detection of the angle θ will be described.

  A method of applying a three-phase AC voltage when detecting a correction value of the position detection signal of the brushless motor will be described. Let V be the peak value of the applied voltage. V is V> 0.

位置検出信号の補正値を検出するときにはこのようにして求めた三相交流電圧をインバータ回路よりモータに印加する。角度θは三相交流電圧の方向となる。

When detecting the correction value of the position detection signal, the three-phase AC voltage thus obtained is applied to the motor from the inverter circuit. The angle θ is the direction of the three-phase AC voltage.

  Next, details of a method for detecting the direction θ of the three-phase AC voltage will be described. With reference to the induced voltage of the brushless motor and the output signal of the position detector shown in FIG. 2, the detection of the changing point from H to L of the signal CS1 during clockwise rotation will be described as a representative.

  From FIG. 2, the position at the electrical angle of 30 degrees is an ideal position of the changing point from H to L of the signal CS1 at the time of clockwise rotation. Let this ideal position be θcs1 *. On the other hand, the three-phase AC voltage is slowly rotated while performing the voltage control. When the direction θ of the three-phase AC voltage is gradually increased, the rotor of the brushless motor rotates clockwise, and CS1 which is one of the output signals of the position detector changes from H to L around 30 °. The direction of the three-phase AC voltage at this time is θcs1.

  For example, as shown in FIG. 3, when the signal CS1 almost coincides with 0 V (zero volt) of the line induced voltage Euw, θcs1 is about 30 °. Also, as shown in FIG. 4, when the signal CS1 is ahead of the line induced voltage Euw, θcs1 is a value smaller than 30 °. Further, when the signal CS1 is delayed from the line induced voltage Euw as shown in FIG. 5, θcs1 becomes a value larger than 30 °. The detected θcs1 is stored in the storage means 5 of FIG. 1 as a correction value for the position detection signal.

  The method for detecting the correction value of the position detection signal has been described above. When the brushless motor is driven in the clockwise direction, for example, when the brushless motor is driven in the clockwise direction, CS1 which is one of the position detection signals has changed from H to L. Sometimes, the ideal position θcs1 * of 30 ° is not used, and the correction value θcs1 of the position detection signal stored in advance in the storage means is used as angle information to drive the brushless motor efficiently. be able to.

  For the sake of explanation, the change point of CS1 from H to L, which is one of the position detector signals when the rotor of the brushless motor rotates clockwise, has been described. However, other signals CS2, CS3, and L to H The correction value of the position detection signal can be detected by the same method for the change point.

  When detecting the correction value of the position detection signal, for example, when the motor is connected to a load and affected by friction, the rotor of the brushless motor follows with a slight delay from the direction θ of the three-phase AC voltage. It is expected that. The brushless motor is rotated clockwise and counterclockwise, and the direction of the three-phase AC voltage when the output signal of the position detector changes is detected in each rotation direction. The average value of the detected values is stored in the storage means as the correction value of the position detection signal of the brushless motor, so that it can be detected without being affected by friction and can be driven efficiently when the brushless motor is driven.

  When the brushless motor is other than two poles, for example, when there are four poles, the change point from H to L of CS1 which is one of the position detection signals when the rotor described in the first embodiment is clockwise is: There are two places 180 degrees apart in the mechanical angle of the motor. If the positions of the change points from H to L of the two signals CS1 are different, there is a possibility that the error of the correction value of the position detection signal becomes large if only one point is detected. In this case, the change point of CS1 from H to L in two position detection signals separated by 180 ° in mechanical angle is detected, and the average value is stored in the storage means as a correction value of the position detection signal of the brushless motor. Even a 4-pole brushless motor can be driven efficiently during driving. In the case of brushless motors with more poles, similarly, the direction θ of the three-phase AC voltage at the signal change point for the number of pole pairs is detected and stored in the storage means. can do.

  Further, when detecting the correction value of the position detector, the correction value of the position detector can be detected with high accuracy by slowly changing the direction of the three-phase AC voltage and rotating the brushless motor slowly. On the other hand, when there are many change points of the position detection signal to be corrected, or when it is desired to detect an average value of a plurality of change points of the same signal as a correction value as in Embodiment 3 with a motor having four or more poles, a brushless motor If the three-phase AC voltage is slowly rotated from the beginning to the end of detection of the correction value, the time required for correction of the position detector becomes longer. In the present invention, the direction θ of the three-phase AC voltage is slowly changed in the vicinity where the correction value of the position detector is desired to be obtained, and the brushless motor is rotated slowly. The time required for acquiring the correction value of the position detector can be shortened by changing the speed quickly and rotating the brushless motor quickly.

  Further, the storage means for storing the correction value of the position detection signal is a non-volatile memory, so that, for example, the motor control device of the present invention corrects the position detection signal at the time of shipment from the factory and stores the correction value of the position detection signal By storing in the nonvolatile memory as means, the correction value is stored even when the power is turned off, and the brushless motor can be driven efficiently without performing correction of the position detection signal when the power is turned on again.

In addition, a washing machine, particularly a drum-type washing machine or a drum-type washing / drying machine, needs to be driven at a low speed and a large torque during washing and at a high speed and a low torque during dehydration. When a brushless motor is used as a drum driving motor of a drum-type washing machine or drum-type washing / drying machine, it is desired to increase the induced voltage to some extent in order to ensure efficiency during washing. Therefore, since the induced voltage of the motor is relatively high with respect to the power supply voltage during dehydration, it is common to perform advance angle control. By mounting the motor control device of the present invention on a drum type washing machine or drum type washing and drying machine, the drum can be driven efficiently, and an efficient drum type washing machine or drum type washing and drying machine is realized. Can do.

  As described above, the motor control device according to the present invention realizes a motor control device that efficiently drives a brushless motor from a low speed to a high speed without being affected by variations in the detection position of the position detector.

DESCRIPTION OF SYMBOLS 1 Control circuit 2 Brushless motor 3 Position detector 5 Memory | storage means C Capacitor

Claims (6)

A brushless motor, a position detector that detects a rotor position of the brushless motor, an inverter that drives the brushless motor, and a control circuit that controls the inverter that drives the brushless motor based on an output signal of the position detector; Storage means associated with the control circuit,
The control means includes
Apply a three-phase AC voltage to the winding of the brushless motor,
Rotate the three-phase AC voltage applied to the winding of the brushless motor,
Detecting the direction of the three-phase AC voltage when the output signal of the position detector changes,
Storing the detected value of the direction of the three-phase AC voltage in the storage means as a correction value of the position detection signal of the brushless motor;
During operation of the brushless motor, the brushless motor is controlled using the output signal of the position detector and the correction value of the position detection signal.
Motor control device. Rotate the brushless motor clockwise and counterclockwise,
Detect the direction of the three-phase AC voltage when the output signal of the position detector changes in each rotation direction,
An average value of the detected values in the direction of the three-phase AC voltage is stored in a storage means as a correction value of the position detection signal of the brushless motor.
The motor control device according to claim 1. The direction of the detected three-phase AC voltage is the same period as the number of pole pairs of the brushless motor.
The average value of the detected values in the direction of the three-phase AC voltage is stored in the storage means as a correction value of the position detection signal of the brushless motor.
The motor control device according to claim 1. The range in which the correction value of the position detection signal is not detected is faster than the rotation speed of the three-phase AC voltage in the vicinity where the correction value of the position detection signal is detected.
The motor control device according to claim 1. The motor control device according to claim 1, wherein the storage unit is a nonvolatile memory. A washing machine or a washing dryer provided with the motor control device according to claim 1.

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