JP2018042694A - Washing machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a washing machine in which an inverter-driven washing machine can efficiently consume rotation energy at the time of deceleration by a resistance component of a motor and shorten a braking time with easy control setting. SOLUTION: A rotating drum 1 that houses laundry and is driven to rotate, an inverter circuit 7 that converts DC power into AC power, a motor 4 that drives the rotating drum 1 by the inverter circuit 7, and a rotation of the motor 4. The number of revolutions detecting means 17 for detecting the number, the current detecting means 9 for detecting the motor current of the motor 4, and the input voltage controlling means 15 for controlling the applied voltage to the motor 4 are provided, and the input voltage controlling means 15 comprises: By controlling the phase current of the motor 4 to be constant during the braking operation of the motor 4, the rotational energy at the time of deceleration can be efficiently consumed by the resistance component of the motor 4, and the braking time can be shortened with easy control settings. . [Selection diagram] Figure 2

Description

  The present invention relates to a washing machine that drives a motor by an inverter circuit.

  Conventionally, this type of washing machine uses a stronger field control and a weaker field control in combination to facilitate control of regenerative power during brake operation, and consumes generated energy in the internal resistance of the motor to reduce the DC voltage of the inverter circuit. Abnormal rise is prevented (for example, refer to Patent Document 1).

JP 2003-088168 A

  However, such a conventional washing machine controls the field current and the torque current separately, which complicates the control, and also increases the brake time in order to suppress the regeneration of rotational energy during deceleration. Had.

  The present invention solves the above-described conventional problems, and an object thereof is to provide a washing machine capable of shortening the brake time with easy control setting.

  In order to solve the above-described conventional problems, a washing machine of the present invention includes a rotating drum that accommodates laundry and is rotationally driven, an inverter circuit that converts DC power into AC power, and the rotating drum that is driven by the inverter circuit. A rotation speed detection means for detecting the rotation speed of the motor, a current detection means for detecting a motor current of the motor, and an input voltage control means for controlling an applied voltage to the motor, The input voltage control means controls the phase current of the motor to be constant during the brake operation of the motor. Here, the phase current is a maximum phase current that can be safely controlled.

  As a result, the brake time can be shortened with easy control settings.

  The washing machine of the present invention can shorten the brake time with an easy control setting.

Sectional drawing of the principal part of the washing machine in Embodiment 1 of this invention Block circuit diagram of motor driving device of the washing machine Time chart of motor control of the washing machine Flow chart of dehydration process of the washing machine Flowchart of rotation speed DOWN subroutine of the washing machine Flow chart of motor drive subroutine of the washing machine Flow chart of carrier signal interrupt subroutine of the washing machine Flowchart of position signal interrupt subroutine of the washing machine Flow chart of rotation speed control subroutine of the washing machine

  According to a first aspect of the present invention, in the washing machine of the present invention, a rotating drum that accommodates laundry and is driven to rotate, an inverter circuit that converts DC power into AC power, and a motor that drives the rotating drum by the inverter circuit A rotation speed detection means for detecting the rotation speed of the motor; a current detection means for detecting a motor current of the motor; and an input voltage control means for controlling a voltage applied to the motor. By controlling the phase current of the motor at a constant during the braking operation of the motor, the maximum current can be supplied to the motor within a range in which no demagnetization of the motor or failure of the inverter circuit occurs. The rotational energy can be efficiently consumed by the resistance component of the motor, and the braking time can be shortened.

  As a result, a large current can flow through the motor without causing demagnetization of the motor or failure of the inverter circuit, and the rotational energy during deceleration can be efficiently consumed by the resistance component of the motor to shorten the braking time. Can do.

  Further, the motor current detected by the current detection means is decomposed into a current component corresponding to the magnetic flux and a current component corresponding to the torque, and each is controlled independently, and a current component corresponding to the torque Rotational speed control means for controlling to an arbitrary set rotational speed, and DC voltage detection means for detecting a DC voltage applied to the inverter circuit, the rotational speed control means is configured to control the DC voltage before and during the brake operation. The reduction rate of the set rotational speed is changed according to the change.

  As a result, the magnetic flux current (current component corresponding to the magnetic flux) can be calculated from the torque current to be controlled (current component corresponding to the torque) and the detected phase current, and the reduction rate of the set rotational speed and the phase current can be set. Easily consumes the rotational energy during deceleration with the resistance component of the motor easily and shortens the braking time. When the DC voltage increases due to regeneration, the deceleration of the set rotational speed is moderated and the rotation stops. Brake control can be performed safely by reducing the torque acting in the direction. Conversely, if there is a DC voltage margin, the set speed can be decelerated faster and the brake time can be shortened.

  The current control means limits a current component corresponding to the torque acting in the rotation stop direction of the motor to a predetermined current or less during a brake operation.

  As a result, it is possible to suppress the torque acting in the rotation stop direction and to prevent the frictional noise of the belt connecting the motor and the rotating drum and the reduction gear failure due to excessive torque fluctuation.

  Further, the transition from the motor drive to the brake operation of the current control means is performed when the current component corresponding to the torque in the rotation direction of the motor becomes zero and the torque in the rotation stop direction of the motor is changed after a lapse of a predetermined time. The corresponding current component was controlled.

  Thereby, an excessive torque fluctuation from the rotation direction to the rotation stop direction can be suppressed, and the frictional noise of the belt connecting the motor and the rotation drum and the failure of the speed reducer can be prevented.

According to a second aspect of the present invention, in the first aspect of the present invention, the motor current detected by the current detection unit is decomposed into a current component corresponding to the magnetic flux and a current component corresponding to the torque, and each is controlled independently. And a rotational speed control means for controlling the rotational speed to an arbitrary set rotational speed by a current component corresponding to the torque, and a DC voltage detecting means for detecting a direct current voltage applied to the inverter circuit. By changing the decrease rate of the set rotational speed according to the change of the DC voltage before driving and during braking, the rotational energy during deceleration can be easily consumed efficiently by the resistance component of the motor, and the braking time can be reduced. If the DC voltage increases due to regenerative regeneration, slow down the set rotation speed, weaken the torque acting in the rotation stop direction, It is possible to carry out your safely. Conversely, if there is a DC voltage margin, the set speed can be decelerated faster and the brake time can be shortened.

  According to a third invention, in the first or second invention, the current control means limits a current component corresponding to the torque acting in a rotation stop direction of the motor to a predetermined current or less during a brake operation. As a result, the torque acting in the rotation stop direction can be suppressed, and the frictional noise of the belt connecting the motor and the rotating drum and the failure of the speed reducer due to excessive torque fluctuation can be prevented.

  According to a fourth aspect of the present invention, in the first to third aspects of the present invention, the transition of the current control means from motor drive to brake operation is predetermined after the current component corresponding to the torque in the rotational direction of the motor is zero. By controlling the current component corresponding to the torque in the rotation stop direction of the motor after a lapse of time, the excessive torque fluctuation from the rotation direction to the rotation stop direction is suppressed, and the friction noise of the belt connecting the motor and the rotary drum, A reduction gear failure can be prevented.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a main part of a washing machine according to Embodiment 1 of the present invention, and FIG. 2 is a block circuit diagram of a motor driving device of the washing machine. In FIG. 1, a rotating drum 1 is formed in a bottomed cylindrical shape, provided with a large number of water passage holes on the outer peripheral portion thereof, and is rotatably disposed in a water receiving tank 2. One end of a rotation shaft (rotation center shaft) provided in the tilt direction is fixed to the rotation center of the rotary drum 1, and a drum pulley 3 is fixed to the other end of the rotation shaft. Note that the direction of the rotation axis of the rotation axis is inclined downward from the horizontal direction from the front side of the washing machine toward the back side as the bottom.

  A motor 4 is attached to the back surface of the water receiving tank 2. The motor 4 is connected to the drum pulley 3 by a belt 5, and the motor 4 is configured and rotated so that the rotating drum 1 can be rotated forward or reverse. . Several projecting plates are provided on the inner wall surface of the rotating drum 1, and the laundry is caught by the projecting plates at the time of rotation and dropped from an appropriate height. The water receiving tub 2 is suspended by a top plate of the washing machine main body so as to be swingable by a spring body, and the opening on the front side of the rotary drum 1 is covered with a lid body so as to be freely opened and closed.

  As shown in FIG. 2, the AC power supply applies AC power to the rectifier circuit 6, the rectifier circuit 6 constitutes a voltage doubler rectifier circuit, and the full-wave rectifier diode 6a causes a capacitor 6b when the AC power supply is positive. When the AC power supply is a negative voltage, the capacitor 6c is charged, a double voltage DC voltage is generated across the capacitors 6b and 6c connected in series, and the double voltage DC voltage is applied to the inverter circuit 7.

  The inverter circuit 7 is constituted by a three-phase full-bridge inverter circuit composed of six power switching semiconductors and an antiparallel diode, and normally includes an insulated gate bipolar transistor (IGBT), an antiparallel diode, its driving circuit, and a protection circuit. It consists of an intelligent power module (hereinafter referred to as IPM). The motor 4 is connected to the output terminal of the inverter circuit 7 and driven.

  The motor 4 is constituted by a direct current motor, and a relative position (rotor position) between the permanent magnet and the stator constituting the rotor is detected by the position detecting means 8. The position detection means 8 is usually composed of three hall sensors 8a, 8b, 8c and detects a position signal for every 60 electrical angles.

The current detection means 9 connects shunt resistors 9a, 9b, 9c between the negative voltage terminal of the inverter circuit 7 and the negative voltage terminal of the rectifier circuit 6, and also receives the input current of the inverter circuit 7 calculated from the voltage across the shunt resistor. In addition, the phase currents Iu, Iv, and Iw of the motor 4 are detected. Usually, a shunt resistor is used, but it can also be detected by an AC current transformer or a DC current transformer.

  The control means 10 controls the number of revolutions of the motor 4 by controlling the inverter circuit 7 based on the information on the motor phase and the motor phase current detected by the position detection means 8 and the current detection means 9. is there. A microcomputer and an inverter control timer (PWM timer) built in the microcomputer, a high-speed A / D conversion circuit, a memory circuit (ROM, RAM), and the like are used to detect the electrical angle from the output signal of the position detection means 8 The angle detection means 11, the output signal of the current detection means 9 and the signal of the electrical angle detection means 11 are decomposed into a d-axis current Id which is a current component corresponding to the magnetic flux and a q-axis current Iq which is a current component corresponding to the torque. Three-phase / two-phase dq conversion means 12, storage means 13 for storing sine wave data (sin, cos data) necessary for conversion from a stationary coordinate system to a rotation coordinate system, or inverse conversion, and a magnetic flux Two-phase / three-phase dq reverse conversion means 14 for converting the voltage component Vd and the voltage component Vq corresponding to the torque into three-phase motor drive control voltages Vu, Vv, Vw, and three-phase Over motor drive control voltage Vu, Vv, and a like input voltage control means 15 for controlling the PWM output for controlling the IGBT switching of the inverter circuit 7 according to Vw.

  The control means 10 detects the motor rotation speed and the drum rotation speed from the setting change means 16 that controls the start, stop, rotation speed, braking, etc. of the motor 4 according to the load, and the output signal of the position detection means 8. The rotational speed detection means 17, the rotational speed control means 18 for controlling the rotational speed of the rotary drum 1 in accordance with the output signal of the rotational speed detection means 17, the d axis (direct) from the setting change means 16 and the rotational speed control means 18. -Axis) current setting signal Ids (d-axis current setting value Ids), q-axis (quadture-axis) current setting signal Iqs (q-axis current setting value Iqs), and Id calculated by the three-phase / 2-phase dq conversion means 12 And a current control means 19 for calculating a voltage component Vd corresponding to the magnetic flux for controlling the motor current and a voltage component Vq corresponding to the torque. That.

  Torque control can be performed by performing feedback control so that the q-axis current Iq corresponding to the torque becomes the q-axis current set value Iqs.

  Since the DC voltage applied to the inverter circuit 7 may be superposed by the regenerative energy generated by the rotation of the motor 4 in addition to the input from the AC power supply, it is always detected by the DC voltage detection means 20.

  FIG. 3 shows the waveform relationship of each part, and the edge signals of the output signals H1, H2, and H3 of the hall sensors 8a, 8b, and 8c change every 60 degrees, and the angle obtained by dividing 360 degrees from each part state signal is determined. it can. A high edge where the signal H1 changes from low to high is indicated as a reference electrical angle of 0 degree, and the U-phase winding induced voltage Ec of the motor 4 has a waveform delayed by 30 degrees from the reference signal H1. Maximum efficiency is obtained when the phases of the U-phase motor current Iu and the U-phase winding induced voltage Ec are the same. The motor induced voltage Ec is the same axis as the q axis, and the d axis is delayed by 90 degrees. Since the q-axis current is in phase with the motor induced voltage phase, it is called torque current.

  In FIG. 3, the U-phase motor current Iu slightly advances from the U-phase winding induced voltage Ec, and the motor applied voltage Vu shows a waveform advanced 30 degrees from the U-phase winding induced voltage Ec. Vc is a sawtooth waveform (or triangular wave) carrier signal generated in the input voltage control means 15, and Vu is a sinusoidal U-phase control voltage, which is a PWM signal u that compares the carrier signal Vc and the U-phase control voltage Vu. It is generated in the input voltage control means 15 and added as a control signal for the U-phase upper arm transistor of the inverter circuit 7. ck is a synchronizing signal of the carrier signal Vc, and is an interrupt signal when the carrier counter counts up and overflows.

  Coordinate conversion from the stationary coordinate system to the rotating coordinate system, that is, dq conversion, is performed with the electrical angle at which the rotor magnet axis of the motor 4 and the magnetic flux axis of the stator coincided as the d axis, and a reference electrical angle of 0 degrees. 11 detects electrical angles such as 30 degrees, 90 degrees, and 150 degrees from the output signals H1, H2, and H3 of the hall sensors 8a, 8b, and 8c, and calculates the electrical angle θ by estimation except every 60 degrees.

  In general, a current component corresponding to the magnetic flux is called a d-axis current Id, and the torque is zero because the permanent magnet magnetic flux and the field magnetic flux are coaxially attracted to the field magnet. Further, the axis that is the same as the induced voltage phase at an electrical angle of 90 degrees from the d-axis and is the torque maximum is called the q-axis, and is a current component corresponding to the torque, and is therefore called the q-axis current Iq. Furthermore, since increasing the d-axis current in the negative direction is equivalent to weakening the field magnetic flux on the d-axis, this is called field-weakening control or field-weakening control (or flux-weakening control). Also, since it is divided into d-axis current and q-axis current and controlled independently, it is called vector control.

  The three-phase / two-phase dq conversion means 12 converts the d-axis current Id and the q-axis current Iq from the motor currents Iu, Iv, and Iw according to the following formula 1, and converts the static coordinate system to the rotating coordinate system. The d-axis current Id and the q-axis current Iq are calculated from the instantaneous motor current value detected corresponding to the electrical angle θ.

  Since the storage unit 13 stores data of sin θ and cos θ, it can be decomposed into the d-axis current Id and the q-axis current Iq by calling the data corresponding to the electrical angle data and performing the product-sum operation. The detection of the electrical angle θ and the detection of the instantaneous motor current value are performed in synchronization with the carrier signal, and will be described in detail according to the flowchart described later.

  The rotation speed detection means 17 detects the motor rotation speed from any one of the output signals H1, H2, and H3 of the hall sensors 8a, 8b, and 8c, and rotates from the number of poles of the motor 4 and the ratio of the drum pulley 3 and the motor pulley. The drum rotational speed signal is converted into the detected rotational speed n of the drum 1 and the drum rotational speed signal is applied to the setting change means 16 and the rotational speed control means 18.

  The setting changing means 16 performs start-up control of the motor 4 and setting of the drum rotation speed, and calculation of the d-axis current setting value Ids according to the drum rotation speed and the q-axis current setting value Iqs, and the rotation speed control means 18 is rotated. The set rotational speed Ns of the drum 1 is added, and the d-axis current set value Ids is added to the current control means 19.

The rotational speed control means 18 compares the detected rotational speed n of the rotating drum 1 (hereinafter referred to as detected rotational speed) with the set rotational speed Ns of the rotating drum 1 (hereinafter referred to as set rotational speed). And an error signal Δn between the detected rotational speed n and the set rotational speed Ns, and torque current setting means 18b for controlling the q-axis current set value Iqs in accordance with the change rate (acceleration) of the rotational speed.

  The current control means 19 compares the output signals Iq and Id of the three-phase / two-phase dq conversion means 12 with the setting signals Iqs and Ids and outputs control voltage signals Vq and Vd, respectively. The q-axis current comparison means 19a , Q-axis voltage setting means 19b, d-axis current comparison means 19c, and d-axis voltage setting means 19d, and generate control voltage signals Vq and Vd for controlling the q-axis current Iq and the d-axis current Id, respectively.

  The d-axis current set value Ids is a signal applied from the setting change means 16 to the current control means 19, and in the case of an embedded magnet motor, the d-axis current set value Ids is increased in accordance with the rotational speed to perform field weakening control. Do. In the case of a surface magnet motor, Ids is normally set to zero, and Ids is increased in the case of high rotational speed driving.

  The two-phase / three-phase dq inverse conversion means 14 calculates the three-phase motor drive control voltages Vu, Vv, Vw from the control voltage signals Vq, Vd according to the following equation 2, and converts the rotating coordinate system to the stationary coordinate system. Then, in synchronization with the carrier signal, a sinusoidal signal corresponding to the electrical angle θ detected by the electrical angle detection means 11 is applied to the input voltage control means 15. The method of product-sum calculation of sin θ and cos θ stored in the storage means 13 is almost the same as the calculation of the three-phase / 2-phase dq conversion means 12.

  In the above configuration, the operation and action will be described with reference to FIGS.

  FIG. 4 is a flowchart of the dehydration process. The dehydration process is started from step 100, various initial settings of the dehydration process are performed at step 101, and a set rotation speed UP subroutine for increasing the set rotation speed Ns with time is executed at step 102. . In step 103, the motor drive subroutine shown in FIG. 6 is executed. In step 104, it is determined whether or not the set rotational speed Ns has reached the final set rotational speed Nsmax (for example, 900 r / min). If Nsmax is reached, the process proceeds to step 105, and the motor drive subroutine is executed in the same manner as in step 103. If Nsmax or less, the process returns to step 102.

In step 106, it is determined whether the dehydration set time T1 (for example, 5 minutes) has elapsed, and the motor drive in step 105 is continued until it elapses.
Step 107 waits for the start of brake operation, and step 108 stores the DC voltage Vdc before the brake start detected by the DC voltage detection means 20. In step 109, it is determined whether or not a set time T2 (for example, 0.5 seconds) has elapsed. The process returns to step 107 until it elapses, and waits for the start of brake operation. The subroutine is executed, and in step 111, the motor drive subroutine is executed in the same manner as in step 103. It is determined whether or not the motor is stopped in step 112. The process returns to step 110 until it stops, and when it stops, the dehydration process is terminated in step 113. .

  A flowchart of the rotational speed DOWN subroutine shown in FIG. 5 will be described. From step 200, the rotational speed DOWN subroutine starts. In step 201, the DC voltage Vdc stored before starting the brake operation is called, in step 202, the set rotational speed reduction rate ΔNs (for example, 80 (r / min) / s) is called, and in step 203, the DC voltage Vdc is set to an arbitrary predetermined value. It is determined whether or not the voltage has increased (for example, 20 V) or more. If the voltage has increased, the set rotational speed decrease rate ΔNs is decreased in step 204 (for example, −0.5 (r / min) / s) Suppresses regeneration to the DC voltage Vdc due to a sudden change in the rotational speed, and if not increased, skips step 204.

  In step 205, it is determined whether or not the DC voltage Vdc has decreased by an arbitrary predetermined voltage (for example, 20V) or more. If the DC voltage Vdc has decreased, the set rotational speed decrease rate ΔNs is increased in step 206 (for example, every 10 ms). +0.5 (r / min) / s), the brake time is shortened while suppressing regeneration to the DC voltage Vdc, and if not decreased, step 206 is skipped. In step 207, the set rotational speed Ns is stored, and in step 208, the subroutine is returned.

  Although an arbitrary predetermined voltage is set here, it may be set to 0 V, and the set rotational speed reduction rate ΔNs may be immediately decreased or increased in accordance with the increase or decrease of the DC voltage Vdc.

  Next, the flowchart of the motor drive subroutine shown in FIG. 6 will be described. From step 300, the motor drive subroutine starts. In step 301, the initial determination is made at the beginning of the subroutine execution to determine the start or initial braking. If the initial startup or braking is initial, various initial settings are performed in step 302, and parameters are transferred from the main routine and various settings are performed. To do. In step 303, rotation start control or braking initial control is performed. Steps 302 and 303 are executed only once at the beginning. The start-up control is one in which the three-phase motor drive control voltages Vu, Vv, and Vw are set to predetermined motor applied voltages and energized 120 degrees during start-up where the rotational speed feedback control is not possible. Perform a soft start to increase the voltage over time. In the case of braking operation, the negative d-axis current Id is increased, the negative q-axis current Iq is decreased, and soft braking is performed so that no sudden braking torque is applied.

  Next, at step 304, it is determined whether or not there is a carrier signal interrupt. The carrier signal interrupt is executed by an interrupt signal ck (see FIG. 3) generated when the carrier counter of the input voltage control means 15 that performs PWM control overflows. If there is a carrier signal interrupt, At 305, the carrier signal interrupt subroutine shown in FIG.

  A flowchart of the carrier signal interrupt subroutine shown in FIG. 7 will be described. In step 400, the carrier signal interrupt subroutine is started. In step 401, the interrupt signal ck is counted. In step 402, the electrical angle detection means 11 calculates the rotor position electrical angle θ. The rotor position electrical angle θ is a value obtained by multiplying the separately obtained electrical angle Δθ per cycle of the carrier signal by the count value k of the carrier counter k · Δθ, which can be detected by the position detecting means 8 every 60 degrees. Addition to estimate calculation.

  For example, if the motor 4 has 4 poles, the ratio of the drum pulley 3 to the motor pulley is 8.25: 1, the carrier frequency is 15.6 kHz, and the rotation speed is 900 r / min, the motor drive frequency is 240 Hz, and the electrical angle is within 60 degrees. The count value k of the carrier counter is about 11. Therefore, Δθ is about 5.5 degrees. As the motor rotational speed is lower, the count value k within an electrical angle of 60 degrees is higher, and the electrical angle detection resolution in calculation is improved. Therefore, it can be understood that there is no problem even when the rotational speed is low and accuracy is required.

  Next, in step 403, the motor currents Iu, Iv, and Iw are detected by the current detection means 9. In step 404, the three-phase / two-phase dq conversion means 12 performs the three-phase / two-phase dq conversion from the electrical angle θ and the motor currents Iu, Iv, Iw by the calculation of the above equation 1, and the d-axis current Id, the q-axis current. Iq is obtained. In step 405, Id and Iq are stored in memory and used separately as rotation speed control data.

  Next, in step 406, the d-axis control voltage Vd and the q-axis control voltage Vq are called, and in step 407, two-phase / three-phase dq reverse conversion is performed by the two-phase / three-phase dq reverse conversion means 14 by the calculation of Equation 2. Three-phase control voltages Vu, Vv, and Vw are obtained. This inverse transformation uses sin θ and cos θ data corresponding to the electrical angle θ of the storage means 13 as in step 404, and performs a product-sum operation at high speed.

  In step 408, PWM output values PWMu, PWMv, and PWMw corresponding to the three-phase control voltages Vu, Vv, and Vw are converted, and in step 409, PWM output is performed from the input voltage control means 15 to the inverter circuit 7 for PWM control. In step 410, the three-phase PWM output values PWMu, PWMv, and PWMw are stored and used in the next carrier signal interrupt. In step 411, the subroutine is returned.

  As described with reference to FIG. 3, the PWM control is performed by comparing the sawtooth wave (or triangular wave) carrier signal with the control voltages Vu, Vv, and Vw corresponding to the U phase, V phase, and W phase. The IGBT on / off control signal of the circuit 7 is generated and the motor 4 is driven in a sine wave. The signals of the upper arm transistor and the lower arm transistor are reversed waveforms. When the conduction ratio of the upper arm transistor is increased, the output voltage is When the positive voltage is increased and the conduction ratio of the lower arm transistor is increased, the output voltage is negative. When the conduction ratio is 50%, the output voltage becomes zero.

  When the control voltage is changed in a sine wave shape corresponding to the electrical angle θ, a sine wave current flows. In the case of sine wave drive, when the transistor conduction ratio is set to the maximum value of 100%, the output voltage is maximum and the modulation degree Am is 100%. When the maximum value of the conduction ratio is 50%, the output voltage is minimum and the modulation is performed. The degree Am is called 0%.

  Since 3-phase / 2-phase dq conversion and 2-phase / 3-phase dq reverse conversion for vector control of motor current are executed at high speed for each carrier signal, high-speed current control is possible. Since the q-axis current Iq, which is a torque current, is detected, the load amount can be determined instantaneously.

  After execution of the carrier signal interrupt subroutine (step 305), the process returns to FIG. When any one of the position signals H1, H2, and H3 from the position detecting means 8 is changed, an interrupt signal is generated, and the position signal interrupt subroutine shown in FIG. As shown in FIG. 3, an interrupt signal is generated every 60 degrees of electrical angle.

Here, the flowchart of the position signal interrupt subroutine shown in FIG. 8 will be described. In step 500, the position signal interrupt subroutine is started. In step 501, the position signals H1, H2, and H3 are input to the electrical angle detection means 11 to perform position detection. In step 502, the rotor electrical angle θc is detected from the position signal. In step 503, the count value k counted in the carrier signal interrupt subroutine is stored in kc. In step 504, the count value k is cleared. In step 505, the count value kc of the carrier counter between 60 electrical degrees is obtained. The electrical angle Δθ of one carrier is calculated.

  Next, in step 506, it is determined whether or not the interrupt signal is based on the reference position signal H1. If the reference position signal is interrupted, in step 507, the count value T of the rotation period measuring timer is stored as the period To, and in step 508, the count value is stored. T is cleared, and in step 509, the detected rotational speed n of the rotary drum 1 is calculated. Next, at step 510, counting of the rotation period measurement timer is started, and at step 511, the subroutine is returned.

  If the detection resolution of the rotation period measurement timer is set to 8-bit accuracy, the clock becomes 64 μs and the carrier signal can be used for the clock. However, in order to improve the rotation control performance, it is necessary to improve the rotation period detection resolution. The period must be set to 1 to 10 μs. In this case, the microcomputer system clock is divided and used as the clock.

  The rotation speed detection method described above is a method for obtaining from the cycle of the position signal H1, but the position signal H2 or H3 may be used, or the position signals H1, H2, and H3 may be used. Good. If the carrier signal is a triangular wave, the carrier counter timer has a period twice that of the sawtooth wave. Therefore, if the triangular wave overflow signal is used as a clock, the resolution is improved. Therefore, the triangular wave timer overflow signal may be used as a clock.

  After executing the position signal interrupt subroutine (step 307), returning to FIG. 6, the rotational speed control subroutine is executed in step 308. In step 309, the subroutine is returned.

  Here, the flowchart of the rotation speed control subroutine shown in FIG. 9 will be described. In step 600, the rotational speed control subroutine is started. In step 601, the detected rotational speed n of the rotary drum 1 is called.

  In step 602, it is determined whether the driving is normal driving or braking. If the driving is normal driving, the set rotational speed Ns increases or becomes constant, and positive torque control is performed. In step 603, a q-axis current set value Iqs is set based on an error between Ns and n. Normally, while Ns is increasing, Ns> n and torque is applied in the acceleration direction, so Iqs is 0 or more. In step 604, the d-axis current set value Ids set in the direction of weakening the magnetic flux according to the detected rotation speed n of the rotary drum 1 is called so that the DC voltage is not regenerated by the induced voltage generated by the rotation of the motor 4.

  If the brake operation is performed in step 602, the set rotational speed Ns is decreased, so negative torque control is performed. In step 605, the q-axis current set value Iqs is set by the error between Ns and n as in step 603. Normally, when Ns is decreasing, Ns <n, and torque is applied in the deceleration direction, so Iqs is 0 or less.

  In step 606, the upper limit value Iqmax of the q-axis current Iq acting in the braking direction is called in order to prevent parts failure due to sudden noise or sudden torque change, and if the absolute value | Iqs | exceeds Iqmax, step In step 607, Iqs is set to −Iqmax so that the absolute value of the q-axis current Iq does not exceed the upper limit value Iqmax. If the absolute value | Iqs | is equal to or less than Iqmax, step 607 is skipped.

  In step 608, from the maximum line current Iuvw_max and the q-axis current set value Iqs that have a margin (for example, 90%) with respect to the demagnetizing current of the motor and the rated current of the circuit components including the inverter components, The d-axis current set value Ids is calculated by

  As described above, during the brake operation, the phase current of the motor 4 is controlled to be constant. In addition, the maximum phase current that can be safely controlled during brake operation flows, and the deceleration rate of the set rotation speed is adjusted in accordance with the increase or decrease of the DC voltage applied to the inverter circuit 7 to suppress the DC voltage while reducing the rotation speed Energy can be efficiently consumed by the resistance component of the motor 4, and the brake time can be shortened with easy control settings.

  After obtaining the d-axis current set value Ids in step 604 and step 608, the d-axis current Id is called in step 609, and Id and Ids are compared in magnitude in step 610. Id is determined from the d-axis current set value Ids. If so, the d-axis control voltage Vd is decreased in step 611. If Id is smaller than the d-axis current set value Ids, the d-axis control voltage Vd is increased in step 612.

  Next, in step 613, the q-axis current Iq is called. In step 614, Iq and Iqs are compared in magnitude. If Iq is larger than the q-axis current set value Iqs, the q-axis control voltage Vq is reduced in step 615. If Iq is smaller than q-axis current set value Iqs, q-axis control voltage Vq is increased at step 616.

  Next, the d-axis control voltage Vd and the q-axis control voltage Vq calculated in step 617 are stored in memory, and in step 618, the subroutine is returned.

  Since the d-axis current Id and the q-axis current Iq are basically converted for each carrier signal, the fluctuation including the torque ripple is large. When the converted d-axis current Id, q-axis current Iq and d-axis and q-axis current setting values Ids, Iqs are compared and controlled for each carrier, the fluctuation element is large and the control is not stable. Need to be added.

  Therefore, as shown in FIG. 9, the rotation speed control subroutine is not executed in the carrier signal interruption subroutine or the position signal interruption subroutine, but is executed independently in the motor drive control. However, in order to increase the response speed of the rotation control, a method performed in the position signal interruption subroutine is also conceivable, but there is a drawback that the response is delayed when the rotation speed is low.

  In the above description, a belt-driven washing machine in which a rotating drum is driven by a belt is described as an example. However, even in a direct-drive washing machine in which a rotating drum and a motor are coaxial, the drum rotation speed becomes the motor rotation speed. By simply passing the maximum phase current that can be safely controlled during braking, adjusting the deceleration rate of the set rotational speed according to the increase or decrease of the DC voltage applied to the inverter circuit, and suppressing the DC voltage, the rotation during deceleration Energy can be efficiently consumed by the resistance component of the motor, and the braking time can be shortened with easy control settings.

  In addition, the above is an example of a drum-type washing machine. However, even in a pulsator-type vertical washing machine in which the rotation drive shaft of the motor is connected to a stirring blade or a washing and dewatering tub by a clutch, it is safe during braking operation. Pass the maximum controllable phase current, adjust the deceleration rate of the set rotation speed according to the increase or decrease of the DC voltage applied to the inverter circuit, and reduce the DC voltage while reducing the rotational energy during deceleration with the motor resistance component. The brake time can be shortened with simple control settings.

  As described above, in the washing machine according to the present invention, in the inverter-driven washing machine, the maximum phase current that can be safely controlled during the brake operation flows, and the set rotational speed is adjusted according to the increase or decrease of the DC voltage applied to the inverter circuit. Adjusting the deceleration rate and suppressing DC voltage, the rotational energy during deceleration can be efficiently consumed by the resistance component of the motor, and the brake time can be shortened with easy control settings. Useful as such.

DESCRIPTION OF SYMBOLS 1 Rotating drum 2 Water receiving tank 3 Drum pulley 4 Motor 5 Belt 6 Rectifier circuit 7 Inverter circuit 8 Position detection means 9 Current detection means 10 Control means 11 Electrical angle detection means 12 3 phase / 2 phase dq conversion means 13 Storage means 14 2 Phase / three-phase dq reverse conversion means 15 Input voltage control means 16 Setting change means 17 Speed detection means 18 Speed control means 19 Current control means 20 DC voltage detection means

Claims (4)

A rotating drum that accommodates laundry and is rotationally driven, an inverter circuit that converts DC power into AC power, a motor that drives the rotating drum by the inverter circuit, and a rotational speed detection that detects the rotational speed of the motor Means, current detection means for detecting the motor current of the motor, and input voltage control means for controlling the voltage applied to the motor, wherein the input voltage control means is a phase of the motor during brake operation of the motor. A washing machine characterized by controlling a current to be constant. The motor current detected by the current detection means is decomposed into a current component corresponding to the magnetic flux and a current component corresponding to the torque, and each of them is controlled independently, and a current component corresponding to the torque Rotational speed control means for controlling to a set rotational speed, and DC voltage detection means for detecting a DC voltage applied to the inverter circuit, the rotational speed control means is adapted to change the DC voltage before and during the brake operation. The washing machine according to claim 1, wherein the reduction rate of the set rotational speed is changed accordingly. The washing machine according to claim 1 or 2, wherein the current control means limits a current component corresponding to the torque acting in a rotation stop direction of the motor to a predetermined current or less during a brake operation. The transition from the motor drive to the brake operation of the current control means corresponds to the torque in the rotation stop direction of the motor after a predetermined time has elapsed since the current component corresponding to the torque in the rotation direction of the motor has been made zero. The washing machine according to any one of claims 1 to 3, wherein the current component is controlled.

Images