JP5121623B2 - Washing machine inverter device - Google Patents

Description

The present invention relates to a washing machine of the inverter apparatus for performing the washing operation by a permanent magnet motor comprising a permanent Hisa磁 stone low coercive force to the rotor magnet.

Generally, in a washing machine configured to perform a washing operation by the rotational driving force generated by controlling the motor by the inverter circuit, when the motor is overloaded or stepped out, or when a failure occurs in the inverter circuit Since an overcurrent may flow, a means for detecting the overcurrent is provided (for example, refer to Patent Document 1), and abnormal processing such as stopping the operation when an overcurrent is detected is performed.
JP 2008-104481 A

  By the way, the applicant has, as a motor for a washing machine, a first permanent magnet and a coercive force on the rotor side that are smaller than the first permanent magnet and have a level of coercivity that can easily change the amount of magnetization. For example, Japanese Patent Application No. 2007-289886 proposes to use a permanent magnet motor including a rotor magnet including a second permanent magnet. When the permanent magnet motor as described above is used, it is necessary to pass an exciting current for changing the magnetization amount of the second permanent magnet to the stator winding via the inverter circuit. The amount of the excitation current is considerably larger than the current when the washing operation is performed, and in order to control the magnetization amount, it is necessary to appropriately control the excitation current amount.

However, since the washing machine using the permanent magnet motor has a relatively new configuration, a specific configuration for appropriately controlling the excitation current has not been proposed yet.
The present invention has been made in view of the above circumstances, and an object of the present invention is to control excitation current with a simple configuration when using a permanent magnet motor capable of changing the magnetization amount of a rotor magnet. An object of the present invention is to provide an inverter device for a washing machine.

To achieve the above object, an inverter device of the washing machine of the present invention, the rotor side, is configured with a rotor magnet made of permanent magnets that have a readily changeable levels of coercive force magnetizing amount It is installed in a washing machine that performs washing operation by the rotational driving force generated by the permanent magnet motor.
An inverter circuit for controlling the permanent magnet motor;
Current detection means for detecting current flowing through the inverter circuit;
Through the inverter circuit, before a magnetizing amount control means for generating the excitation current so as to vary the magnetization amount of KiHisashi permanent magnet,
When the magnetization amount control means is operated to flow the exciting current, a current limit threshold is set for the current detected by the current detection means, and the current detection means is It is used as a means for limiting excitation current.

As described above, since a washing machine is generally provided with a means for detecting current, if a threshold for overcurrent detection is set and compared with respect to the current detected by the current detection means, magnetization is performed. It can also be used to control when the excitation current is generated to change the magnetization amount of the amount control means GaHisashi permanent magnet.

According to the washing machine of the inverter device of the present invention, even when using a permanent magnet motor capable of changing the magnetization amount of the rotor magnet, changing the magnetization amount of the permanent magnet by diverting the existing current sensing means Since the exciting current can be limited as described above, the operation characteristics of the washing machine can be stabilized by controlling the magnetization amount with high accuracy.

(First embodiment)
Hereinafter, a first embodiment in which the present invention is applied to a heat pump type washer / dryer (laundry device) will be described with reference to FIGS. In FIG. 8 showing the longitudinal side surface of the drum type washing and drying machine, a water tank 2 is elastically supported by a plurality of support devices 3 in a horizontal state inside the outer box 1. Inside the water tank 2, a rotating drum (rotating tank) 4 is rotatably arranged coaxially therewith. The rotating drum 4 has a large number of dewatering holes 4a (only part of which are shown) serving as ventilation holes on the peripheral side wall and the rear wall, and also functions as a washing tub, a dewatering tub, and a drying chamber. A plurality of baffles 4 b (only one is shown) are provided on the inner peripheral surface of the rotating drum 4.

  Each of the outer box 1, the water tank 2 and the rotating drum 4 has openings 5, 6 and 7 for putting in and out the laundry on the front surface (right side in the figure). The opening 6 is connected in a watertight manner by an elastically deformable bellows 8. The opening 5 of the outer box 1 is provided with a door 9 for opening and closing the opening. The rotating drum 4 has a rotating shaft 10 on the back surface, and the rotating shaft 10 is supported by a bearing (not shown) and is an outer rotor type attached to the outside of the back surface of the water tank 2. It is rotationally driven by a drum motor (washing / dehydrating motor, permanent magnet motor) 11 comprising a three-phase brushless DC motor. The rotating shaft 10 is integral with the rotating shaft of the motor 11, and the rotating drum 4 is driven by a direct drive system.

  A casing 13 is supported on the bottom plate 1a of the outer box 1 via a plurality of support members 12, and a discharge port 13a and a suction port 13b are formed at the upper right end portion and the upper left end portion of the casing 13, respectively. ing. Moreover, the compressor 15 of the heat pump (refrigeration cycle) 14 is installed in the bottom plate 1a. Further, in the casing 13, a condenser 16 and an evaporator 17 of the heat pump 14 are installed in order from the right side to the left side, and a blower fan 18 is disposed at the right end portion. A dish-shaped water receiving portion 13 c is formed at a portion of the casing 13 located below the evaporator 17.

  In the water tank 2, an intake port 19 is formed in the upper part of the front surface part, and an exhaust port 20 is formed in the lower part of the back surface part. The intake port 19 is connected to the discharge port 13 a of the casing 13 through a linear duct 21 and an extendable connecting duct 22. Further, the exhaust port 20 is connected to the suction port 13 b of the casing 13 via an annular duct 23 and an extendable connecting duct 24. The annular duct 23 is attached to the outside of the back surface of the water tank 2 and is formed concentrically with the drum motor 11. That is, the inlet side of the annular duct 23 is connected to the exhaust port 20, and the outlet side is connected to the suction port 13 b via the connecting duct 24. The casing 13, the connecting duct 22, the linear duct 21, the intake port 19, the exhaust port 20, the annular duct 23, and the connecting duct 14 constitute an air circulation path 25.

  In the outer box 1, a water supply valve 26 composed of a three-way valve is disposed at the upper rear portion thereof, and a detergent feeder 26a is disposed at the upper upper portion thereof. The water supply valve 26 has a water inlet connected to a water faucet via a water supply hose, a first water outlet connected to an upper water inlet of the detergent feeder 26a via a water supply hose 26b for washing, The water outlet is connected to the lower water inlet of the detergent dispenser 26a through the rinsing water supply hose 26c. And the water outlet of the detergent feeder 26a is connected to the water inlet 2a formed in the upper part of the water tank 2 via the water supply hose 26d.

  A drain port 2b is formed at a rear portion of the bottom of the water tank 2, and the drain port 2b is connected to the drain hose 27 via a drain valve 27a. A part of the drain hose 27 is telescopic. And the water receiving part 13c of the casing 13 is connected to the middle part of the drainage hose 27 via the drainage hose 28 and the check valve 28a.

  An operation panel unit 29 is provided on the front upper portion of the outer box 1, and the operation panel unit 29 is provided with a display and various operation switches (not shown). In addition, a display / operation board 84 is provided on the rear surface of the operation panel unit 29, and communicates with a control circuit (magnetization amount control means) 30 built in the substrate case 120 to operate the operation panel unit 29. Is controlled. The control circuit 30 is constituted by a microcomputer, and controls the water supply valve 26, the drum motor 11 and the drain valve 27a according to the operation of the operation switch of the operation panel unit 29, and washing, rinsing and dewatering washing operations, The drying operation is executed by controlling a compressor motor (compressor motor, not shown) composed of a three-phase brushless DC motor that drives the drum motor 11 and the compressor 15.

FIG. 9 schematically shows a drive system of the drum motor 11. The inverter circuit (PWM control system inverter) 32 is configured by connecting six IGBTs (semiconductor switching elements) 33a to 33f in a three-phase bridge, and between the collectors and emitters of the IGBTs 33a to 33f, there is a flywheel diode. 34a-34f are connected.
The emitters of the IGBTs 33d, 33e, 33f on the lower arm side are connected to the ground through shunt resistors (current detection means) 35u, 35v, 35w. The common connection point between the emitters of the IGBTs 33d, 33e, and 33f and the shunt resistors 35u, 35v, and 35w is connected to the control circuit 30 via the level shift circuit 36, respectively. Incidentally, since a maximum of about 15 A flows through the windings 11u to 11w of the drum motor 11, the resistance values of the shunt resistors 35u to 35w are set to 0.1Ω, for example.

  The level shift circuit (current detection means) 36 includes an operational amplifier and the like, amplifies the terminal voltage of the shunt resistors 35u to 35w and adjusts the output range of the amplified signal to the positive side (for example, 0 to +3. 3V) A bias is applied. The overcurrent comparison circuit (current detection means) 38 receives the output of the level shift circuit 36, and performs overcurrent detection in order to prevent the circuit from being destroyed when the upper and lower arms of the inverter circuit 32 are short-circuited.

  A driving power supply circuit 39 is connected to the input side of the inverter circuit 32. The drive power supply circuit 39 rectifies a 100V AC power supply 40 by a full-wave rectification circuit 41 composed of a diode bridge and a double voltage full-wave rectification by two capacitors 42a and 42b connected in series, and a DC voltage of about 280V. Is supplied to the inverter circuit 32. Each phase output terminal of the inverter circuit 32 is connected to each phase winding 11 u, 11 v, 11 w of the drum motor 11.

The control circuit 30 reads the currents Iau to Iaw flowing through the windings 11u to 11w of the motor 11 obtained through the level shift circuit 36 by A / D conversion by the A / D conversion unit 74, and based on the current value. The phase θ of the secondary rotating magnetic field and the rotational angular velocity ω are estimated, and the three-phase current is subjected to orthogonal coordinate transformation and dq (direct-quadrature) coordinate transformation to obtain an excitation current component Id and a torque current component Iq.
When a speed command is given from the outside, the control circuit 30 generates current commands Idref and Iqref based on the estimated phase θ, rotational angular velocity ω, and current components Id and Iq, and converts them into voltage commands Vd and Vq. Then, rectangular coordinate transformation and three-phase coordinate transformation are performed. Finally, a drive signal is generated as a PWM signal and output to the windings 11 u to 11 w of the motor 11 via the inverter circuit 32.

  The first power supply circuit 43 steps down the drive power supply of about 280V supplied to the inverter circuit 32 to generate a control power supply of 15V and supplies it to the control circuit 30 and the drive circuit 44. The second power supply circuit 45 is a three-terminal regulator that generates 3.3V power from the 15V power generated by the first power circuit 43 and supplies the 3.3V power to the control circuit 30. The high voltage driver circuit 46 is arranged to drive the IGBTs 33 a to 33 c on the upper arm side in the inverter circuit 32.

Further, the rotor of the motor 11 is provided with a rotational position sensor 78 (u, v, w) constituted by, for example, a Hall IC for use at startup, and the rotational position sensor 78 (position detecting means) outputs The rotor position signal is supplied to the control circuit 30. That is, when the motor 11 is started, vector control is performed using the rotational position sensor 78 until the rotational speed at which the rotor position can be estimated (for example, about 30 rpm), and after reaching the rotational speed, Switch to sensorless vector control without using the rotational position sensor 78.
The compressor motor is not shown in detail, but has a configuration that is substantially symmetrical with the drive system of the drum motor 11.

A series circuit of resistance elements 79 a and 79 b is connected between the output terminal of the power supply circuit 39 and the ground, and the common connection point is connected to the input terminal of the control circuit 30. The control circuit 30 reads the input voltage of the inverter circuit 32 divided by the resistance elements 79a and 79b and uses it as a reference for determining the PWM signal duty.
In addition, the control circuit 30 controls various electrical components 83 such as a door lock control circuit and a drying fan motor, and inputs / outputs operation signals and control signals to / from the display / operation board 84 described above. To do.

  FIG. 10 is a functional block diagram of sensorless vector control performed by the control circuit 30 for the drum motor 11 (and the compressor motor). This configuration is the same as that disclosed in, for example, Japanese Patent Application Laid-Open No. 2003-181187, and will be schematically described here. In FIG. 10, (α, β) indicates an orthogonal coordinate system obtained by orthogonally transforming a three-phase (UVW) coordinate system with an electrical angle interval of 120 degrees corresponding to each phase of the motor 11, and (d, q) is The coordinate system of the secondary magnetic flux which is rotating with rotation of the rotor of the motor 11 is shown.

  The subtracter 62 is supplied with the target speed command ωref from the speed command output unit 60 as a subtracted value and the detected speed ω of the motor 11 detected by the estimator 63 as a subtracted value. The result is given to a speed PI (Proportional-Integral) control unit 65. The speed PI control unit 65 performs PI (proportional integration) control based on the difference between the target speed command ωref and the detected speed ω, and generates and subtracts the q-axis current command value Iqref and the d-axis current command value Idref. Are output as subtracted values to the devices 66q and 66d, respectively. The subtractors 66q and 66d are respectively provided with the q-axis current value Iq and the d-axis current value Id output from the αβ / dq conversion unit 67 as subtraction values, and the subtraction results are respectively supplied to the current PI control units 68q and 68d. Given. The control period in the speed PI control unit 65 is set to 1 msec.

  The current PI controllers 68q and 68d perform PI control based on the difference amount between the q-axis current command value Iqref and the d-axis current command value Idref, and generate the q-axis voltage command value Vq and the d-axis voltage command value Vd. And output to the dq / αβ conversion unit 69. The dq / αβ conversion unit 69 is given a rotational phase angle (rotor position angle) θ of the secondary magnetic flux detected by the estimator 63, and voltage command values Vd and Vq are converted into voltage commands based on the rotational phase angle θ. Convert to values Vα and Vβ.

  The voltage command values Vα and Vβ output from the dq / αβ conversion unit 69 are converted into three-phase voltage command values Vu, Vv and Vw by the αβ / UVW conversion unit 70 and output. The voltage command values Vu, Vv, Vw are given to one fixed contact 71ua, 71va, 71wa of the changeover switches 71u, 71v, 71w, and are output from the initial pattern output unit 76 to the other fixed contact 71ub, 71vb, 71wb. Voltage command values Vus, Vvs, and Vws are given. The movable contacts 71uc, 71vc, 71wc of the changeover switches 71u, 71v, 71w are connected to the input terminal of the PWM forming unit 73.

  The PWM forming unit 73 modulates a 15.6 kHz carrier (triangular wave) based on the voltage command values Vus, Vvs, Vws or Vu, Vv, Vw, and outputs PWM signals Vup (+,-), Vvp (+, -), Vwp (+,-) is output to the inverter circuit 32. The PWM signals Vup to Vwp are output as signals having a pulse width corresponding to the voltage amplitude based on the sine wave so that, for example, a sine wave current is passed through the phase windings 11u, 11v, and 11w of the motor 11.

The A / D converter 74 outputs current data Iau, Iav, and Iaw obtained by A / D converting voltage signals appearing at the emitters of the IGBTs 33 d to 33 f to the UVW / αβ converter 75. The UVW / αβ conversion unit 75 converts the three-phase current data Iau, Iav, Iaw into two-axis current data Iα, Iβ in an orthogonal coordinate system according to a predetermined arithmetic expression. Then, the biaxial current data Iα and Iβ are output to the αβ / dq converter 67.
The αβ / dq conversion unit 67 obtains the rotor position angle θ of the motor 11 from the estimator 63 at the time of vector control, thereby obtaining the biaxial current data Iα, Iβ on the rotational coordinate system (d, q) according to a predetermined arithmetic expression. When converted into the d-axis current value Id and the q-axis current value Iq, they are output to the estimator 63 and the subtractors 66d and 66q as described above.

  The estimator 63 estimates the rotor position angle θ and the rotational speed ω based on the q-axis voltage command value Vq, the d-axis voltage command value Vd, the q-axis current value Iq, and the d-axis current value Id, and outputs them to each unit. . Here, when the motor 11 is started, a startup pattern is applied by the initial pattern output unit 76 and forced commutation is performed. Thereafter, when the rotational position sensor 78 performs vector control based on the sensor signal, the estimator 63 is activated, and the process proceeds to sensorless vector control in which the position angle θ and the rotational speed ω of the drum motor 11 are estimated. In the case of a compressor motor, the process shifts from forced commutation to sensorless vector control.

  The switching control unit 77 controls switching of the selector switch 71 based on the duty information of the PMW signal given from the PWM forming unit 73. In the above configuration, the configuration excluding the inverter circuit 32 is a block of functions realized by the software of the control circuit 30. The current control period in the vector control is set to 128 μsec, for example. However, the PWM carrier wave period is 64 μsec on the drum motor 11 side and 128 μsec on the compressor motor side. The control circuit 30 and the inverter circuit 32 constitute an inverter device 99.

  FIG. 7A is a plan view schematically showing the overall configuration of the drum motor 11, and FIG. 7B is a perspective view showing a part thereof in an enlarged manner. The drum motor 11 includes a stator 91 and a rotor 92 provided on the outer periphery of the stator 91. The stator 91 includes a stator core 93 and stator windings 11u, 11v, and 11. The stator core 93 has an annular yoke portion 93a and a large number of teeth portions 93b protruding radially from the outer peripheral portion of the yoke portion 93a. The stator windings 11u, 11v, and 11w It is wound.

  The rotor 92 has a structure in which a frame 94, a rotor core 95, and a plurality of permanent magnets 96, 97 are integrated with a mold resin (not shown). The frame 94 is formed into a flat bottomed cylindrical shape by pressing, for example, an iron plate that is a magnetic material. The permanent magnets 96 and 97 constitute a rotor magnet 98.

  The rotor core 95 is disposed on the inner peripheral portion of the peripheral side wall of the frame 94, and the inner peripheral surface thereof is formed in a concavo-convex shape having a plurality of convex portions 95a that protrude in an arc shape toward the inside. . Inside these convex portions 95a, there are formed rectangular insertion holes 95b and 95c penetrating in the axial direction and having different short sides, and these are alternately arranged in an annular shape one by one. Yes. Neodymium magnets 96 (first permanent magnets) and alnico magnets 97 (second permanent magnets) are inserted into the respective insertion holes 95b and 95c. In this case, the coercive force of the neodymium magnet 96 is about 900 kA / m, the coercive force of the alnico magnet 97 is about 100 kA / m, and the coercive force differs by about 9 times.

  Further, each of these two types of permanent magnets 96 and 97 forms one magnetic pole, and each of the two types of permanent magnets 96 and 97 has a total of 48, for example, 24 each so that the magnetization direction is along the radial direction of the permanent magnet motor 1. Are arranged. In this way, by arranging the two types of permanent magnets 96 and 97 alternately so that their magnetization directions are along the radial direction, the adjacent permanent magnets 96 and 97 have magnetic poles in opposite directions. (A state in which one N pole is inside and the other N pole is outside), and a magnetic path (magnetic flux) is generated between the neodymium magnet 96 and the Alnico magnet 97 in the direction indicated by the arrow B, for example. That is, a magnetic path passing through both the neodymium magnet 96 having a large coercive force and the alnico magnet 97 having a small coercive force is formed.

  FIG. 1 shows the configuration shown in FIG. 9 with respect to a part according to the gist of the present invention, and shows a level shift circuit 36U and an overcurrent comparison circuit 38U corresponding to the U phase in a concrete circuit. Although not shown in FIG. 9, a snubber capacitor 100 having a capacitance of about 0.22 μF, for example, is connected between the positive and negative power supply buses of the inverter circuit 32 (this is shown in FIG. 9). On the other hand, the smoothing capacitors 42a and 42b are electrolytic capacitors of about 820 μF, for example).

  The level shift circuit 36U constitutes an amplifier circuit by the operational amplifier 101, and the non-inverting input terminal of the operational amplifier 101 is connected to the emitter of the IGBT 33d through the resistance element 102 and is set to 5 V through the resistance element 103. Pulled up. Further, the inverting input terminal of the operational amplifier 101 is connected to the ground via the resistance element 104 and is connected to its own output terminal via the resistance element 105.

  The overcurrent comparison circuit 38U is configured around a comparator (excitation current limiting means) 106, and its inverting input terminal is connected to the output terminal of the operational amplifier 101. Further, the non-inverting input terminal of the comparator 106 is connected to 5 V via the resistance element 107 and is connected to the ground via the resistance element 108. Further, a series circuit of the switch SW1 and the resistance element 109 and a series circuit of the switch SW2 and the resistance element 110 are connected between the non-inverting input terminal and the ground.

  That is, the threshold voltage of the comparator 106 can be changed by the control circuit 30 performing on / off control of the switches SW1 and SW2. When the drum motor 11 is normally operated by the inverter circuit 32, both the switches SW1 and SW2 are set to ON, and the threshold voltage of the comparator 106 is set to the most corresponding to overcurrent detection (for example, about 10A). Set to a low voltage. Note that the detection signal of the comparator 106 is low active (of course, it may be high active).

  In FIG. 1, only the level shift circuit 36U and the overcurrent comparison circuit 38U corresponding to the U phase are shown, but the same configuration is also provided for the W phase. Since the V phase is not used in the magnetization control, a comparator in which the threshold voltage corresponding to the overcurrent detection is fixedly set is provided as in the conventional case.

  Next, the operation of this embodiment will be described with reference to FIGS. In the configuration of this embodiment, when the weight of the laundry stored in the rotating drum 4 is detected (load amount sensing, detection processing), or when low speed rotation / high output torque is required, such as washing / rinsing operation. In this case, the magnetic flux of the entire rotor magnet 98 is increased by increasing (magnetizing) the magnetization amount of the alnico magnet 97, and when high speed rotation / low output torque is required as in the dehydrating operation, the alnico magnet 97 Is controlled so as to decrease the magnetic flux of the entire rotor magnet 98.

  FIG. 5 is a flowchart schematically showing a series of steps from washing to dehydration in the washing machine. When the operation is started, the control circuit 30 first performs a magnetizing operation (step S101), and then performs load amount sensing (step S102). In addition, load amount sensing uses the method currently disclosed by Unexamined-Japanese-Patent No. 2004-267334, for example, and makes the rotary drum 4 by maximum acceleration from the time estimated that the laundry distribution state in the rotary drum 4 was balanced. The integrated value of the q-axis current during the acceleration period is obtained. In this case, the maximum rotation number of the drum motor 11 is, for example, about 170 rpm.

  Then, when the amount of detergent put into the rotary drum 4 and the amount of water supply are determined according to the load amount obtained in step S102, a washing operation is performed (step S103). In this case, the maximum rotation speed of the drum motor 11 is, for example, about 50 rpm. When the washing operation is completed, a demagnetization operation is performed (step S104), and a first dehydration process, which is a pretreatment for “rinsing”, is performed (step S105). In this case, the maximum rotation speed of the drum motor 11 is, for example, about 1300 rpm. Then, a magnetizing operation is performed (step S106), and then a “rinse” stirring operation is performed (step S107). In this case, the maximum number of rotations of the drum motor 11 is the same as the washing operation.

  Subsequently, when the demagnetizing operation is performed again (step S108), the second dehydration, which is a post-treatment of “rinsing”, is performed (step S109), and after the magnetizing operation is performed (step S110), the “rinsing” stirring operation is performed again. Is performed (step S111). Then, after performing a demagnetizing operation (step S112), final dehydration is performed (step S113). Thereafter, a drying operation may be performed as necessary.

  FIG. 3 is a flowchart showing processing when the Alnico magnet 97 is demagnetized from a demagnetized state. First, the control circuit 30 turns off both the switches SW1 and SW2 (step S11). Thereby, the threshold voltage of the comparator 106 is set to the highest voltage corresponding to the limit value (for example, about 20 A) of the excitation current. Next, the drum motor 11 is rotated by forced commutation (for example, d-axis current 3A) while performing current PWM control by the inverter circuit 32, and the rotor 92 is fixed at the position of electrical angle + 30 ° by the position sensor 78 ( Step S12).

  Next, as shown in FIG. 1, the U-phase upper IGBT 33a and the W-phase lower IGBT 33f are turned on simultaneously and energized to the windings 11U and 11W of the motor 11 (step S13). At this time, the control circuit 30 counts the elapsed time from the start of energization of the exciting current with a timer (timer). Then, it is monitored whether or not the detection output of the comparator 106W arranged in the W phase is turned on (low level) (step S14). If the comparator 106W is turned on after 1 msec from the start of energization (step S15: NO) ), The energization by the inverter circuit 32 is turned off for 3 seconds (step S16).

  If “YES” is determined in the step S15, it is a case where magnetization is performed as expected. Here, FIG. 2 shows an example of the excitation current waveform when the magnetization is increased as described above. However, unlike the energization pattern in step S13, the energization is performed for 5 msec by PWM control. The excitation current reaches 21 A in about 4 milliseconds after the start of energization. Therefore, in the case of continuous energization, the degree of increase in current becomes steeper.

Further, the limit value of the excitation current 20A is set to a value corresponding to 90% or less of the current at a level at which the magnetization is completely saturated when the alnico magnet 97 is magnetized. That is, if it is attempted to flow a current at a level at which magnetization is completely saturated, it is necessary to increase the current capacity of the inverter circuit 32 accordingly, resulting in an increase in cost.
Also, in step S16, the energization stop interval of 3 seconds is provided because torque is generated in the motor 11 by energization of the excitation current. Therefore, when energizing continuously, torque against the torque is generated. The motor 11 may rotate discontinuously and generate noise and vibration. In order to avoid such a situation, the above interval is provided.

  After execution of step S16, the rotor is fixed again at the position of electrical angle + 30 ° in the state rotated by one electrical angle (1/24 mechanical angle) in the same manner as step S12 (step S17). As in S13, an exciting current is applied to the windings 11U and 11W of the motor 11 (step S18). If the comparator 106W is turned on after 1 msec from the start of energization (step S20: YES, S21: NO), the energization is turned off for 3 seconds (step S21), and finally the switches SW1 and SW2 are both turned on ( Step S22) The process is terminated.

  Here, as shown in FIG. 7A, the Alnico magnets 97 are arranged in the order of U, V, W,... In the clockwise direction. For example, when the rotor 92 is positioned with reference to the uppermost U phase, the stator 91 Alnico magnets 97 to which the teeth 93b face are arranged in the order of U, W, V, U, W, V,. Therefore, in step S13, every other alnico magnet 97 is magnetized as described above, and the alnico magnet 97 located between them is in an incompletely magnetized state. Therefore, if the rotor 92 is moved by one electrical angle in step S18, the remaining alnico magnet 97 can be favorably magnetized.

  On the other hand, when an excitation current is applied in step S13 or S18, if 20 msec (upper limit value) has elapsed since the start of energization (steps S23, S27: YES), for example, the voltage of the AC power supply 40 is insufficient, so the excitation current Is assumed to be unable to supply at a sufficient level. Alternatively, it may be considered that an abnormality or failure has occurred in the inverter circuit 32 or the motor 11. Therefore, if the switch SW1 is not turned on at that time (steps S24, S28: YES), the switch SW1 is turned on after taking the energization stop inverter valve for 3 seconds as in steps S16, S21 (step S25). , S29, abnormality determination means). As a result, the threshold value of the comparator 106 </ b> W decreases when the resistance element 109 is connected in parallel (for example, set to a value corresponding to about the current values 17 </ b> A to 18 </ b> A). Then, after demagnetizing processing is once performed (steps S26 and S30), the process proceeds to steps S12 and S17, respectively, and the magnetization is tried again in the same manner.

  Even if the switch SW1 is turned on, if 20 msec has elapsed since the start of energization and the comparator 106W has not been turned on, “YES” is determined in steps S24 and S28, and energization by the inverter circuit 32 is stopped (step S24). S31), failure determination processing is performed (step S32, abnormality determination means).

FIG. 4 is a flowchart showing processing when the alnico magnet 97 is demagnetized from the magnetized state. Steps S13, S14, S18, S19, S26, and S30 of FIG. , S14D, S18D, S19D, S26D, and S30D.
That is, in steps S13D and S18D, as shown in FIG. 1, the W-phase upper IGBT 33c and the U-phase lower IGBT 33d are continuously turned on at the same time, and the exciting currents are reversed in the windings 11W and 11U of the motor 11. Energize. In steps S14D and S19D, it is monitored whether or not the detection output of the comparator 106U disposed in the U phase is turned on. Further, in steps S26D and S30D, before the switch SW1 is turned on and demagnetization is attempted again, the magnetizing process is performed.

Further, FIG. 6 shows step S102 in FIG. 5 depending on whether the magnetizing process of the alnico magnet 97 in FIG. 3 is completed without changing the threshold value of the comparator 106 or when the switch SW1 is turned on. An example of changing a determination value (q-axis current integrated value) for performing weight determination of the laundry by load amount sensing performed in FIG.
That is, when the magnetizing process of the alnico magnet 97 is completed with the switch SW1 turned on, the magnetic flux amount of the entire rotor magnet 98 is lower than the expected value as a result of lowering the threshold value of the comparator 106. Therefore, the output torque of the motor 11 also slightly decreases, and it is desirable to change the reference for determining the load amount based on the q-axis current obtained in the vector control. In FIG. 6, the value for determining the weight of the same range is changed so as to be set higher when the switch SW1 is turned on.

As described above, according to this embodiment, when the drum motor 11 includes the rotor magnet 98 including the neodymium magnet 96 and the alnico magnet 97 on the rotor 92 side, the drum motor 11 flows through the inverter circuit 32. A comparator 106 for detecting an overcurrent by comparing the current with a detection threshold, and a control circuit 30 for generating an excitation current so as to change the amount of magnetization of the alnico magnet via the inverter circuit 32 are provided. When a current is applied, the threshold value set in the comparator 106 is changed to a current limit threshold value that is larger than the threshold value for overcurrent detection, so that the comparator 106 is used as a means for limiting excitation current.
Therefore, the excitation current can be limited so that the amount of magnetization of the alnico magnet 97 can be changed by diverting the comparator 106 arranged for overcurrent detection, so that the amount of magnetization can be controlled with high accuracy and the washing machine can be operated. The characteristics can be stabilized. By using the comparator 106, the current change state can be determined at high speed.

  In addition, the control circuit 30 measures the time from when the energization of the excitation current is started until the comparator 106 detects that the excitation current exceeds the current limit threshold, and when the time exceeds 20 milliseconds, Since the alnico magnet 97 is magnetized again after the switch SW1 is turned on and the current limiting threshold set in the comparator 106 is decreased, the magnetization control is not completed due to a shortage of voltage, for example. Can be completed by lowering the threshold. Alternatively, it can be more reliably determined step by step whether or not it is due to a failure of the inverter circuit 32 or the like.

Further, the control circuit 30 stops energization for 3 seconds when the current limit threshold is decreased or when the position of the rotor 92 is changed by one electrical angle and magnetization is continued without decreasing the current limit threshold. Since the period is provided, the influence of the torque generated in the motor 11 due to the energization of the excitation current can be eliminated, and the occurrence of inadvertent noise and vibration can be avoided.
In addition, when the current limit threshold is decreased from the initial value, the control circuit 30 corrects the determination value set for evaluating the result of the detection process performed based on the rotation state of the motor 11. Specifically, since the determination value of the process for detecting the weight of the laundry stored in the rotating drum 4 is corrected, even when the output torque of the motor 11 is slightly lower than the expected value, The detection process can be performed accurately.

(Second embodiment)
11 to 14 show a second embodiment of the present invention. The same parts as those in the first embodiment are denoted by the same reference numerals and the description thereof will be omitted, and different parts will be described below. FIG. 11 is a view corresponding to FIG. 1 of the first embodiment. In the second embodiment, the series circuit of the switch SW1 and the resistance element 109 and the series circuit of the switch SW2 and the resistance element 110, which are connected to the non-inverting input terminal of the comparator 106, are deleted. That is, the comparator 106 is provided for overcurrent detection similarly to the conventional configuration, and therefore the resistance element 111 corresponds to a resistance value obtained by connecting the resistance elements 108 to 110 of the first embodiment in parallel. ing.

  When the magnetization control of the alnico magnet 97 is performed, the control circuit (excitation current limiting means) 30 determines whether or not the excitation current has reached the current limit value by the A / D converter (current detection means). , Excitation current limiting means) 74 refers to the data A / D converted, sets the current limit threshold for the data, and compares the data. FIG. 12 shows the timing at which the A / D converter 74 performs A / D conversion. The A / D conversion unit 74 performs A / D conversion at the peak of the triangular wave in synchronization with the carrier wave period (for example, 128 μsec) of PWM control.

  Next, the operation of the second embodiment will be described with reference to FIGS. FIGS. 13 and 14 are diagrams corresponding to FIGS. 3 and 4 of the first embodiment, in which the processing performed using the comparator 106 in the first embodiment is replaced with that performed by the A / D converter 74. Yes. In step S11A, the determination threshold value (current limit value) by the A / D conversion unit 74 is set to 20A. In steps S14A and S19A, the W-phase current data is compared with 20A. Step S22 has been deleted.

  In steps S24A and S28A, it is determined whether or not the determination threshold has been reduced to 17A. In steps S25A and S29A, processing is performed to decrease the determination threshold to 17A. Other processing. The same as in the first embodiment. In FIG. 14, steps S14A and S19A in FIG. 13 are replaced with a process for comparing the U-phase current data with 20A (steps S14D_A and S19D_A), and the magnetizing process in steps S26 and S30 is replaced with the process in steps S26D and S30D. Replaced with demagnetization.

  According to the second embodiment configured as described above, the excitation current limit control accompanying the increase / decrease magnetic processing of the Alnico magnet 97 is performed using the A / D conversion unit 74 instead of the comparator 106. That is, since the A / D conversion cycle is 128 μs, it is possible to sufficiently determine the current change in the order of milliseconds, and the switches SW1, SW1 for switching the threshold voltage of the comparator 106 as in the first embodiment. SW2 and the resistance elements 108 to 110 can be deleted.

The present invention is not limited to the embodiments described above or shown in the drawings, and the following modifications or expansions are possible.
The threshold value of the current value and the energization time is merely an example, and may be changed as appropriate according to the individual design.
The detection process for changing the determination value when the excitation current limit threshold is lowered is not limited to the laundry weight determination, and may be a laundry distribution balance determination in the rotating drum 4, for example. The determination value may be changed as necessary.
The limit threshold value for the excitation current may be changed in two or more stages. For example, also in the first embodiment, when the resistance values of the resistance elements 108 and 109 are different, the threshold value may be lowered in two steps by reversing the on / off of SW1 and SW2 in steps S25 and S29.

The energization stop time in steps S15 and S25 is not limited to 3 seconds and may be changed as appropriate. Also, these steps may be deleted.
The present invention can be applied without being limited to an inverter device that performs vector control.
The first and second permanent magnets are not limited to neodymium magnets and alnico magnets, but the coercive force of the two is different to the extent that the former magnetization state is not affected when the latter magnetization amount is changed. What is necessary is just to select and use suitably.
What is necessary is just to change suitably the output pattern of d-axis current in the case of performing a magnetizing process and a demagnetizing process according to individual design.
You may apply to the washing machine without a drying function.

A semiconductor switching element such as a power MOSFET or a power transistor may be used in place of the IGBT 33.
You may apply to the vertical washing machine which rotates a pulsator, without restricting to a drum type washing machine.
The washing machine is not limited to vector control.
The present invention is not limited to the outer rotor type, and may be applied to an inner rotor type permanent magnet motor.
The rotating shaft of the rotating drum 4 may be inclined by about 10 to 15 degrees in the elevation direction with respect to the horizontal.

FIG. 9 is a first embodiment of the present invention, and shows the configuration shown in FIG. The figure which shows an example of the excitation current waveform in the case of magnetizing an alnico magnet Flowchart showing the process when the alnico magnet is magnetized Flow chart showing processing for demagnetization Flow chart schematically showing a series of steps from washing to dehydration The figure which shows the table which changes the determination value for performing weight determination of the laundry FIG. 1A is a plan view schematically showing an overall configuration of a drum motor, and FIG. Longitudinal side view of drum-type washer / dryer Diagram showing drum motor drive system The figure which shows the functional block of the sensorless vector control which a control circuit performs about a motor FIG. 1 equivalent view showing a second embodiment of the present invention. The figure which shows the timing which performs A / D conversion 3 equivalent figure 4 equivalent diagram

Explanation of symbols

  In the drawings, 4 is a rotating drum (rotating tank), 11 is a drum motor (permanent magnet motor), 30 is a control circuit (magnetization amount control means, time measuring means, abnormality determining means), 32 is an inverter circuit, and 35 is a shunt resistor. (Current detection means), 36 is a level shift circuit (current detection means), 74 is an A / D converter (current detection means, excitation current limiting means), 78 is a rotational position sensor (position detection means), 92 is a rotor, Reference numeral 96 denotes a neodymium magnet (first permanent magnet), 97 denotes an alnico magnet (second permanent magnet), 98 denotes a rotor magnet, 99 denotes an inverter device, and 106 comparators (current detection means, excitation current limiting means).

Claims (7)

The rotor side, a washing machine for performing washing operation by rotational drive force permanent magnet motor generates configured with a rotor magnet made of permanent magnets that have a readily changeable levels of coercive force magnetizing amount Mounted on
An inverter circuit for controlling the permanent magnet motor;
Current detection means for detecting current flowing through the inverter circuit;
Through the inverter circuit, before a magnetizing amount control means for generating the excitation current so as to vary the magnetization amount of KiHisashi permanent magnet,
When the magnetization amount control means is operated to flow the exciting current, a current limit threshold is set for the current detected by the current detection means, and the current detection means is An inverter device for a washing machine, which is used as a means for limiting excitation current. The current detection means is composed of a comparator for overcurrent detection,
The inverter device for a washing machine according to claim 1, wherein the threshold value set in the comparator is changed to a current limit threshold value that is larger than an overcurrent detection threshold value, and is used as a means for limiting the excitation current. Time counting means for timing the time from when the magnetization amount control means starts energizing the excitation current until the excitation current limit means detects that the excitation current exceeds the current limit threshold;
The washing machine according to claim 1 or 2, further comprising an abnormality determination unit that determines an abnormality of the permanent magnet motor or the inverter circuit according to a length of time counted by the timing unit. Inverter device. When time counted by the time counting means exceeds the upper limit value, the operation was a stop of the attachment磁量control means from reducing the current limit threshold, the pre KiHisashi permanent magnet by the deposition磁量control means The inverter device for a washing machine according to claim 3, wherein the inverter device is magnetized again.   A predetermined energization stop period is provided when the current limit threshold is decreased, or when the magnetization amount control means continues to magnetize without decreasing the current limit threshold. 4. The inverter device for a washing machine according to 4.   5. The determination value set for evaluating a result of detection processing performed based on a rotation state of the permanent magnet motor when the current limit threshold is decreased from an initial value is corrected. Or the inverter apparatus of the washing machine of 5.   The inverter device for a washing machine according to claim 6, wherein the detection process is a process of detecting an amount of laundry stored in the rotating tub.

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