JP6751846B2 - Washing machine - Google Patents

Description

The present invention relates to a washing machine in which a motor is driven by an inverter circuit.

Conventionally, this type of washing machine uses both strong field control and weak field control 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. It prevents an abnormal rise (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2003-08816

However, in such a conventional washing machine, since the field current and the torque current are controlled separately, the control becomes complicated, and the braking time becomes long in order to suppress the regeneration of the rotational energy during deceleration. Had.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a washing machine capable of shortening the braking time with easy control settings.

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

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

The washing machine of the present invention can shorten the braking time with easy control settings.

Sectional drawing of the main part of the washing machine according to Embodiment 1 of this invention Block circuit diagram of the motor drive device of the washing machine Motor control time chart of the washing machine Flow chart of dehydration process of the washing machine Flow chart of the rotation speed DOWN subroutine of the washing machine Flowchart of motor drive subroutine of the washing machine Flowchart of carrier signal interrupt subroutine of the washing machine Flowchart of position signal interrupt subroutine of the washing machine Flowchart of rotation speed control subroutine of the washing machine

According to the first aspect of the present invention, the washing machine of the present invention includes a rotating drum that houses and is rotationally driven, an inverter circuit that converts DC power into AC power, and a motor that drives the rotating drum by the inverter circuit. , The rotation speed detecting means for detecting the rotation speed of the motor, the current detecting means for detecting the motor current of the motor, the input voltage controlling means for controlling the applied voltage to the motor, and the current detecting means for detecting. The motor current is decomposed into a current component corresponding to the magnetic flux and a current component corresponding to the torque, and controlled to an arbitrary set rotation speed by the current control means for controlling each independently and the current component corresponding to the torque. The rotation speed control means includes a rotation speed control means and a DC voltage detection means for detecting a DC voltage applied to the inverter circuit, and the rotation speed control means uses the input voltage control means to control the phase current of the motor during braking operation of the motor. the controls constant by comparing the DC voltage in the DC voltage and a brake operation of the front brake operation, the DC voltage in the brake operation the brake operation prior to said DC voltage any given voltage higher than If it has increased, the reduction rate of the set rotation speed is reduced , and if the DC voltage during the braking operation is reduced by an arbitrary predetermined voltage or more from the DC voltage before the braking operation, the set rotation speed is reduced. By increasing the reduction rate of , the maximum current can be passed through the motor within the range where demagnetization of the motor and failure of the inverter circuit do not occur, and the rotational energy during deceleration is efficiently consumed by the resistance component of the motor. , The braking time can be shortened.

As a result, a large current can be passed through the motor within the range where demagnetization of the motor and failure of the inverter circuit do not occur, the rotational energy during deceleration is efficiently consumed by the resistance component of the motor, and the braking time is shortened. Can be done.

Furthermore , the magnetic flux current (current component corresponding to the magnetic flux) can be calculated from the controlled torque current (current component corresponding to the torque) and the detected phase current, and by setting the reduction rate of the set rotation speed and the phase current, The rotational energy during deceleration can be efficiently consumed by the resistance component of the motor to shorten the braking time , and when the DC voltage increases due to regeneration, the deceleration of the set rotation speed is slowed down and the rotation is stopped. Brake control can be performed safely by weakening the torque acting in the direction. On the contrary, if there is a margin of DC voltage, the deceleration of the set rotation speed can be accelerated and the braking time can be shortened.

According to the second invention, in the first invention, the current control means limits the current component corresponding to the torque acting in the rotation stop direction of the motor to a predetermined current or less during brake operation. By suppressing the torque acting in the direction of stopping rotation, it is possible to prevent the friction noise of the belt connecting the motor and the rotating drum and the failure of the speed reducer due to excessive torque fluctuation.

According to the third invention, in the first or second invention, the transition from the motor drive to the brake operation of the current control means takes a predetermined time after the current component corresponding to the torque in the rotation direction of the motor is set to zero. After the lapse of time, by controlling the current component corresponding to the torque in the rotation stop direction of the motor, 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 rotation drum and deceleration It is possible to prevent the failure of the machine.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to this embodiment.

(Embodiment 1)
FIG. 1 is a cross-sectional view of a main part of the washing machine according to the first embodiment of the present invention, and FIG. 2 is a block circuit diagram of a motor drive device of the washing machine. In FIG. 1, the rotary drum 1 is formed in a bottomed cylindrical shape, has a large number of water passage holes on the side wall on the outer peripheral portion, and is rotatably arranged in the water receiving tank 2. One end of a rotation shaft (rotation center shaft) provided in the inclined direction is fixed to the rotation center of the rotation drum 1, and the drum pulley 3 is fixed to the other end of the rotation shaft. The direction of the rotating shaft is inclined downward from the horizontal direction from the front side of the washing machine toward the back side which is 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 rotating drum 1 is configured to rotate forward or reverse by the motor 4 and is rotationally driven. .. Several protrusions are provided on the inner wall surface of the rotating drum 1, and the protrusions hook the laundry during rotation and drop it from an appropriate height, thereby exhibiting the effect of so-called tapping and washing. Further, the water receiving tank 2 is swayably suspended by a spring body by the top plate of the washing machine body, and the opening on the front side of the rotating drum 1 is covered by a lid so as to be openable and closable.

As shown in FIG. 2, the AC power supply applies AC power to the rectifying circuit 6, the rectifying circuit 6 constitutes a voltage doubler rectifying circuit, and a full-wave rectifying diode 6a provides a capacitor 6b when the AC power supply has a positive voltage. When the AC power supply is charged and the AC power supply has a negative voltage, the capacitor 6c is charged, a voltage doubler DC voltage is generated at both ends of the capacitors 6b and 6c connected in series, and a voltage doubler DC voltage is applied to the inverter circuit 7.

The inverter circuit 7 is composed of a three-phase full-bridge inverter circuit composed of six power switching semiconductors and an antiparallel diode, and usually incorporates an insulated gate bipolar transistor (IGBT), an antiparallel diode, its drive circuit, and a protection circuit. It is composed 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 composed of a DC motor, and the position detecting means 8 detects the relative position (rotor position) between the permanent magnets constituting the rotor and the stator. The position detecting means 8 is usually composed of three Hall sensors 8a, 8b, 8c, and detects a position signal at every 60 degrees of the electric angle.

The current detecting means 9 connects the shunt resistors 9a, 9b, 9c between the negative voltage terminal of the inverter circuit 7 and the negative voltage terminal of the rectifying 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. Normally, 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 inverter circuit 7 to control the rotation speed of the motor 4 based on the information of the phase of the motor and the phase current of the motor detected by the position detecting means 8 and the current detecting means 9. is there. Electricity that consists of a microcomputer, an inverter control timer (PWM timer) built into the microcomputer, a high-speed A / D conversion circuit, a memory circuit (ROM, RAM), etc., and detects the electric angle from the output signal of the position detecting means 8. The angle detecting means 11, the output signal of the current detecting means 9, and the signal of the electric angle detecting 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. Corresponding to the three-phase / two-phase dq conversion means 12, the storage means 13 for storing the sinusoidal data (sin, cos data) necessary for converting from the stationary coordinate system to the rotational coordinate system, or the inverse conversion, and the magnetic flux. Two-phase / three-phase dq inverse conversion means 14 that converts the voltage component Vd corresponding to the voltage component Vd and the torque into the three-phase motor drive control voltage Vu, Vv, Vw, and the three-phase motor drive control voltage Vu, Vv, Vw. The input voltage control means 15 for controlling the PWM output for controlling the switching of the IGBT of the inverter circuit 7 is provided accordingly.

Further, the control means 10 detects the motor rotation speed and the drum rotation speed from the setting changing 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 rotation number detecting means 17, the rotation number controlling means 18 that controls the rotation number of the rotating drum 1 according to the output signal of the rotation number detecting means 17, and the d-axis (direct) from the setting changing means 16 and the rotation number controlling means 18. -Axis) Current setting signal Ids (d-axis current set value Ids), q-axis (quadrature-axis) current setting signal Iqs (q-axis current set value Iqs), and Id calculated from the 3-phase / 2-phase dq conversion means 12. And Iq are compared with each other, and the current control means 19 for calculating the voltage component Vd corresponding to the magnetic flux and the voltage component Vq corresponding to the torque for controlling the motor current is provided.

Torque control is possible 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 superimposed 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 detecting 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 into 6 parts is determined from the state signal of each part. it can. The high edge at which the signal H1 changes from low to high is shown as a reference electric angle of 0 degrees, 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 can be obtained by making the phases of the U-phase motor current Iu and the U-phase winding induced voltage Ec the same. The motor-induced voltage Ec is on 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 shows a waveform slightly ahead of the U-phase winding induced voltage Ec, and the motor applied voltage Vu shows a waveform 30 degrees ahead of the U-phase winding induced voltage Ec. Vc is a carrier signal of a serrated waveform (or triangular wave) generated in the input voltage control means 15, and Vu is a PWM signal u comparing the carrier signal Vc and the U-phase control voltage Vu with a sinusoidal U-phase control voltage. It is generated in the input voltage control means 15 and added as a control signal of the U-phase upper arm transistor of the inverter circuit 7. ck is a synchronization signal of the carrier signal Vc, and is an interrupt signal when the carrier counter counts up and overflows.

Since the coordinate conversion from the static coordinate system to the rotating coordinate system, that is, the dq conversion is performed with the electric angle at which the rotor magnet axis of the motor 4 and the magnetic flux axis of the stator coincide with each other as the d-axis and the reference electric angle of 0 degrees, the electric angle detecting means 11 detects electric 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 obtains an electric angle θ by estimation except every 60 degrees.

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

The 3-phase / 2-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 by the following equation 1, and converts the static coordinate system into the rotational coordinate system. , The d-axis current Id and the q-axis current Iq are calculated from the instantaneous values of the motor current detected corresponding to the electric angle θ.

Since the storage means 13 stores the 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 electric angle data and performing the product-sum calculation. The detection of the electric angle θ and the detection of the instantaneous value of the motor current are performed in synchronization with the carrier signal, and detailed description will be given according to a flowchart described later.

The rotation speed detecting 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. It is converted to the detected rotation speed n of the drum 1, and the drum rotation speed signal is added to the setting changing means 16 and the rotation speed controlling means 18.

The setting changing means 16 performs start control of the motor 4, setting of the drum rotation speed, calculation of the d-axis current set value Ids according to the drum rotation speed and the q-axis current set value Iqs, and rotates to the rotation speed control means 18. The set rotation 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 rotation speed control means 18 is a rotation speed comparing means 18a for comparing the detected rotation speed n (hereinafter referred to as the detected rotation speed) of the rotating drum 1 with the set rotation speed Ns (hereinafter referred to as the set rotation speed) of the rotating drum 1. It is composed of an error signal Δn between the detected rotation speed n and the set rotation speed Ns, and a torque current setting means 18b that controls the q-axis current setting value Iqs according to the rate of change (acceleration) of the rotation speed.

The current control means 19 compares the output signals Iq and Id of the 3-phase / 2-phase dq conversion means 12 with the set signals Iqs and Ids, respectively, and outputs the control voltage signals Vq and Vd. The q-axis current comparison means 19a , Q-axis voltage setting means 19b, d-axis current comparing means 19c, and d-axis voltage setting means 19d, and generating 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 changing 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 according to the rotation speed to perform field weakening control. Do. In the case of a surface magnet motor, the Ids are usually set to zero and the Ids are increased in the case of high rotation speed drive.

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

In the above configuration, the operation and operation will be described with reference to FIGS. 4 to 9.

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 in step 101, and a set rotation speed UP subroutine that increases the set rotation speed Ns with time is executed in 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 rotation speed Ns has reached the final set rotation speed Nsmax (for example, 900 r / min), and when 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 it is Nsmax or less, the process returns to step 102.

In step 106, it is determined whether or not the dehydration set time T1 (for example, 5 minutes) has elapsed, the motor drive in step 105 is continued until it elapses, and after that, the motor drive is terminated once.
The start of the brake operation is waited in step 107, and the DC voltage Vdc before the start of braking detected by the DC voltage detecting means 20 in step 108 is stored in the memory. In step 109, it is determined whether or not the set time T2 (for example, 0.5 seconds) has elapsed, the process returns to step 107 until it elapses, the brake operation is continuously waited for, and after that, the set rotation speed DOWN shown in FIG. The subroutine is executed, the motor drive subroutine is executed in the same manner as in step 103 in step 111, it is determined whether or not the vehicle has stopped in step 112, the process returns to step 110 until the vehicle stops, and when the vehicle stops, the dehydration process ends in step 113. ..

The flowchart of the rotation speed DOWN subroutine shown in FIG. 5 will be described. The rotation speed DOWN subroutine starts from step 200. In step 201, the DC voltage Vdc stored before the start of the brake operation is called, in step 202, the set rotation speed reduction rate ΔNs (for example, 80 (r / min) / s) is called, and in step 203, the DC voltage Vdc is an arbitrary predetermined value. It is determined whether or not the voltage (for example, 20 V) has increased, and if it has increased, the set rotation speed reduction rate ΔNs is reduced in step 204 (for example, -0.5 (r / min) / every 10 ms. s) Suppress the regeneration to the DC voltage Vdc due to a sudden change in rotation speed, and if it does not increase, skip step 204.

In step 205, it is determined whether or not the DC voltage Vdc is reduced by an arbitrary predetermined voltage (for example, 20 V) or more, and if it is decreased, the set rotation speed reduction rate ΔNs is increased in step 206 (for example, every 10 ms). +0.5 (r / min) / s), shorten the braking time while suppressing the regeneration to the DC voltage Vdc, and if it does not decrease, skip step 206. The set rotation speed Ns is stored in the memory in step 207, and the subroutine is returned in step 208.

Here, an arbitrary predetermined voltage is set, but it may be set to 0V to immediately decrease or increase the set rotation speed decrease rate ΔNs according to the increase or decrease of the DC voltage Vdc.

Next, the flowchart of the motor drive subroutine shown in FIG. 6 will be described. The motor drive subroutine starts from step 300. In the initial judgment that is determined at the beginning of the subroutine execution in step 301, the activation or braking initial is determined, and if it is the activation or braking initial, various initial settings are made in step 302, and parameters are passed from the main routine and various settings are executed. To do. In step 303, rotation start control or braking initial control is performed. Step 302 and step 303 are initially executed only once. The start control is to set the three-phase motor drive control voltages Vu, Vv, and Vw to a predetermined motor applied voltage and energize 120 degrees at the time of starting when the rotation speed feedback control is not possible, from a low motor applied voltage to a high voltage. Perform a soft start that raises 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 a sudden braking torque is not applied.

Next, in step 304, it is determined whether or not the carrier signal is interrupted. 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, a step is taken. At 305, the carrier signal interrupt subroutine shown in FIG. 7 is executed.

The flowchart of the carrier signal interrupt subroutine shown in FIG. 7 will be described. The carrier signal interrupt subroutine is started from step 400, and the interrupt signal ck is counted in step 401. In step 402, the rotor position electric angle θ is calculated by the electric angle detecting means 11. The rotor position electric angle θ is a value k · Δθ obtained by multiplying the separately obtained electric angle Δθ per cycle of the carrier signal by the count value k of the carrier counter, and the electric angle φ every 60 degrees that can be detected by the position detecting means 8. Estimate calculation by adding.

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 electric 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 rotation speed is lower, the count value k within the electric angle of 60 degrees becomes higher, and the calculation electric angle detection resolution is improved. Therefore, it can be seen that there is no problem even when the rotation speed is low and accuracy is required.

Next, in step 403, the motor currents Iu, Iv, and Iw are detected by the current detecting means 9. In step 404, the three-phase / two-phase dq conversion means 12 performs three-phase / two-phase dq conversion from the electric angles θ and the motor currents Iu, Iv, and Iw by the calculation of the above equation 1, and the d-axis current Id and the q-axis current. Find Iq. 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, 2-phase / 3-phase dq inverse conversion is performed by the 2-phase / 3-phase dq inverse conversion means 14 by the calculation of the above equation 2. The three-phase control voltages Vu, Vv, and Vw are obtained. In this inverse conversion, the product-sum calculation is performed at high speed using the sinθ and cosθ data corresponding to the electric angle θ of the storage means 13 as in step 404.

In step 408, the PWM output values corresponding to the three-phase control voltages Vu, Vv, and Vw are converted to PWMu, PWMv, and PWMw, and in step 409, the input voltage control means 15 PWM outputs to the inverter circuit 7 to perform 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. The subroutine is returned in step 411.

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

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

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

After executing the carrier signal interrupt subroutine (step 305), the process returns to FIG. 6 and the presence / absence of the position signal interrupt is determined in step 306. When any of the position signals H1, H2, and H3 from the position detecting means 8 changes, an interrupt signal is generated, and the position signal interrupt subroutine shown in FIG. 8 is executed in step 307. As shown in FIG. 3, an interrupt signal is generated every 60 degrees of electric angle.

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

Next, in step 506, it is determined whether or not the signal is interrupted by the reference position signal H1, and if the reference position signal is interrupted, the count value T of the rotation cycle measurement timer is stored as the cycle To in step 507, and the count value is stored in step 508. T is cleared, and the detected rotation speed n of the rotating drum 1 is calculated in step 509. Next, the count of the rotation cycle measurement timer is started in step 510, and the subroutine is returned in step 511.

When the detection resolution of the rotation cycle 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 cycle detection resolution of the clock. The period should be set to 1-10 μs. In this case, the system clock of the microcomputer is divided and used as the clock.

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

After executing the position signal interrupt subroutine (step 307), the process returns to FIG. 6 and the rotation speed control subroutine is executed in step 308. The subroutine is returned in step 309.

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

In step 602, it is determined whether the vehicle is in normal drive or brake operation, and if it is in normal drive, the set rotation speed Ns increases or becomes constant, and positive torque control is performed. In step 603, the q-axis current set value Iqs is set by the error between Ns and n. Normally, while Ns is increasing, Ns> n and torque is applied in the acceleration direction, so Iqs becomes 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 rotating 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 rotation speed Ns decreases, so negative torque control is performed. In step 605, the q-axis current set value Iqs is set by the error of Ns and n as in step 603. Normally, while Ns is decreasing, Ns <n and torque is applied in the deceleration direction, so Iqs is 0 or less.

In step 606, in order to prevent abnormal noise due to sudden braking and component failure due to sudden torque change, the upper limit value Iqmax of the q-axis current Iq acting in the braking direction is called, and when the absolute value | Iqs | exceeds Iqmax, the step In 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, and if the absolute value | Iqs | is Iqmax or less, step 607 is skipped.

From the maximum line current Iuvw_max and the q-axis current set value Iqs, which have a margin (for example, 90%) with respect to the demagnetizing current of the motor and the rated current of the circuit component including the inverter component in step 608, the following formula 3 The d-axis current set value Ids is calculated by the calculation of.

As described above, during the braking 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 is passed, and the deceleration rate of the set rotation speed is adjusted according to the increase or decrease of the DC voltage applied to the inverter circuit 7, and the rotation during deceleration is suppressed while suppressing the DC voltage. Energy can be efficiently consumed by the resistance component of the motor 4, and the braking time can be shortened with easy control settings.

After obtaining the d-axis current set value Ids in steps 604 and 608, the d-axis current Id is called in step 609, the magnitude comparison judgment of Id and Ids is performed in step 610, and Id is obtained from the d-axis current set value Ids. If is larger, the d-axis control voltage Vd is decreased in step 611, and if Id is smaller than the d-axis current set value Ids, the d-axis control voltage Vd is increased in step 612.

Next, the q-axis current Iq is called in step 613, the magnitude comparison judgment of Iq and Iqs is performed in step 614, and 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 the q-axis current set value Iqs, the q-axis control voltage Vq is increased in step 616.

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

Since the d-axis current Id and the q-axis current Iq are basically converted for each carrier signal, the fluctuation is large including the torque ripple. If the converted d-axis current Id, q-axis current Iq and the current set values Ids and Iqs of the d-axis and q-axis are compared and controlled for each carrier, the fluctuation factor is large and the control is not stable, so an integration factor such as averaging. Need to be added.

Therefore, as shown in FIG. 9, the rotation speed control subroutine is not executed in the carrier signal interrupt subroutine or the position signal interrupt subroutine, but is executed independently in the motor drive control. However, in order to increase the response speed of the rotation control, a method of performing it in the position signal interrupt subroutine can be considered, but there is a drawback that the response becomes slow when the rotation speed is low.

The above description takes as an example a belt-driven washing machine in which a rotating drum is driven by a belt, but even in a direct-drive type washing machine in which the rotating drum and the motor are coaxial, the drum rotation speed is the motor rotation speed. Just by passing the maximum phase current that can be safely controlled during braking operation, the deceleration rate of the set rotation speed is adjusted according to the increase or decrease of the DC voltage applied to the inverter circuit, and the rotation during deceleration while suppressing the DC voltage. 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, although the above description uses a drum-type washing machine as an example, even in a pulsator-type vertical washing machine in which the rotation drive shaft of the motor is coupled to a stirring blade or a washing / dehydrating tub by a clutch, it is safe to operate the brakes. The maximum phase current that can be controlled is passed, and the deceleration rate of the set rotation speed is adjusted according to the increase or decrease of the DC voltage applied to the inverter circuit, and the rotation energy during deceleration is efficiently controlled by the resistance component of the motor while suppressing the DC voltage. The braking time can be shortened with easy control settings.

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

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 Electric angle detection means 12 3-phase / 2-phase dq conversion means 13 Storage means 14 2 Phase / 3-phase dq inverse conversion means 15 Input voltage control means 16 Setting change means 17 Rotation speed detection means 18 Rotation speed control means 19 Current control means 20 DC voltage detection means

Claims (3)

A rotating drum that accommodates laundry and is driven to rotate, an inverter circuit that converts DC power into AC power, a motor that drives the rotating drum by the inverter circuit, and a rotation speed detection that detects the rotation speed of the motor. Means, a current detecting means for detecting the motor current of the motor, an input voltage controlling means for controlling the applied voltage to the motor, a current component corresponding to the magnetic flux of the motor current detected by the current detecting means, and a torque. A current control means that decomposes into current components corresponding to the above and controls each independently, a rotation speed control means that controls an arbitrary set rotation speed by the current component corresponding to the torque, and a DC voltage applied to the inverter circuit. The direct current control means includes a direct current voltage detecting means for detecting the above, and the input voltage controlling means controls the phase current of the motor to be constant during the braking operation of the motor, and the direct current before the braking operation. compares the voltage and the DC voltage during braking operation, when the DC voltage in the brake operation has not increased any given voltage or more than the DC voltage before the brake operation, the reduction rate of the set rotational speed The feature is that if the DC voltage during the braking operation is reduced by an arbitrary predetermined voltage or more from the DC voltage before the braking operation, the reduction rate of the set rotation speed is increased. Washing machine to do. The washing machine according to claim 1, wherein the current control means limits the current component corresponding to the torque acting in the rotation stop direction of the motor to a predetermined current or less during 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 after the current component corresponding to the torque in the rotation direction of the motor is set to zero. The washing machine according to claim 1 or 2, wherein the current component is controlled.

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