JP2796415B2 - Washing machine cloth measuring device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION The present invention relates to a washing machine, and more particularly to a method for measuring the amount of put clothes. In recent years, home washing machines have become fully automatic, which automatically performs operations from water supply to washing, stirring, rinsing, and dehydration. Among them, a microcomputer is mounted, and the amount of clothes put into the machine is increased. Are automatically measured to determine the amount of water and the stirring time.

[Conventional technology]

Conventionally, in this type of technology, there is a technology in which a load torque applied to a motor for rotating a washing tub, a stirring blade, and the like is regarded as an inertial rotation speed and an inertial rotation speed of the motor. That is, the back electromotive voltage appearing at both ends of the motor rotation capacitor when the motor is off in the on / off pattern of the motor is converted into a pulse at a certain threshold, and the amount of clothing is determined by the number of pulses and the time interval at which the pulse occurs. This is to determine the magnitude.

FIG. 1 (a) measures the time between generated pulses. (A) is a power supply voltage, and the motor
As shown in the figure, on / off, forward / reverse rotation is controlled by a forward / reverse circuit using a switching element such as a triac FLS. (B) shows the current flowing through the motor, and (c) shows various waveforms of the voltage across the capacitor. The current flowing through the motor depends on the characteristics of the motor and the capacity of the capacitor.
The phase is advanced (dashed line) or delayed (dashed line) with respect to the voltage. Further, the phase of the voltage across the capacitor is delayed with respect to the phase of this current. The power supply circuit of the control circuit block diagram shown in FIG.
The zero cross pulse at the voltage zero cross point supplied to the microcomputer (instruction control) at the time of (V) is (d). The on / off of the motor is switched in synchronization with the zero cross pulse. At both ends of the capacitor of the motor, a sensor circuit for generating a pulse signal in one half cycle (positive or negative) of the AC back electromotive force (positive in this embodiment) is provided, and a waveform as shown in FIG. Becomes

FIG. 3 and FIG. 4 are measuring sections of a program for controlling the washing machine.

Conventionally, when a command to stop the motor (part (a) in FIG. 1A) is issued at a half cycle when the pulse signal of the sensor circuit is output for measuring the amount of cloth, the voltage immediately following the instruction is given. The zero cross is forgotten, and at the voltage zero cross after that, an off signal is applied to the gate of the switching element to stop the energization of the motor. When a command to stop the motor (モ ー タ in FIG. 1 (a)) is issued at a half cycle in which the pulse signal of the sensor circuit is not output, an off signal is applied to the gate of the switching element at a voltage zero crossing immediately after that. In addition, the motor was de-energized.

In this way, during the inertial rotation after the power supply to the motor is stopped, the generation timing interval width (time) of the pulse signal before and after output from the sensor circuit is measured, and the cloth amount is measured.

[Problems to be solved by the invention]

However, as described above, the phase of the current flowing through the motor is shifted from the phase of the voltage due to the characteristics of the motor, the capacity of the capacitor, and the like. Therefore, since the current is not 0 when the motor is turned off, a current flows in accordance with the waveforms of FIGS. 1A and 1B until the current becomes 0 (* in FIG. 1). It is not a rotation. In particular, when the phase of the motor current is advanced, the sensor input is turned on during this time. As a result, there is a drawback that the obtained inter-pulse time does not correctly reflect the amount of clothes put in.

[Means for solving the problem]

The present invention relates to a washing tub, a stirring blade rotatably provided on the inner bottom of the washing tub, a driving motor for stirring and driving the stirring blade, and using an AC power supply, and a driving motor connected to the driving motor. A motor rotation capacitor, a front circuit and a reverse rotation circuit connected to both ends of the motor rotation capacitor and having a switching element such as a triac, and an inertia rotation after turning off the power supply to the drive motor. A sensor circuit that converts one (positive or negative) half cycle of the AC back electromotive force that appears at both ends of the motor rotation capacitor into a pulse signal and outputs it, and a microcomputer instruction that takes in the pulse signal of this sensor circuit And a control unit for measuring the amount of laundry in the washing tub based on the width of the timing of generation of the pre- and post-fetched pulses. Where the pulse signal of the sensor circuit is output in a half cycle, when the instruction control unit issues an instruction to stop the energization of the driving motor for measuring the amount of cloth, the voltage of the AC power supply that comes immediately after that. An off signal is added to the switching element a little after dt time from the zero crossing, and a half cycle where the pulse signal of the sensor circuit is not output,
When the instruction control unit issues an instruction to stop the energization of the drive motor for measuring the amount of cloth, the voltage zero crossing immediately after the instruction is skipped and the switching element is turned off by slightly delaying dt time from the next voltage zero crossing. It is characterized by adding a signal.

By doing so, when the transition from the half cycle side of the AC back electromotive force where the pulse signal of the sensor circuit is not output to the half cycle side where the pulse signal of the sensor circuit is output, the OFF signal is applied to the switching element in advance. Therefore, the energization of the motor is stopped at the transition to the next half cycle. For this reason, the pulse signal of the sensor circuit used for measuring the cloth amount can be obtained as a signal having a decentralized inertia rotation in which power supply is stopped.

〔Example〕

As shown in (g) of FIG. 1 (b), when a command to stop the motor (indicated by a triangle) is issued at a half cycle in which the pulse signal of the sensor circuit is being output, the voltage zero crossing that immediately follows the instruction is started. An off signal is applied to the gate of the switching element with a slight delay by the dt time. Since the off signal is applied just before the motor current of the next half cycle flows, the energization is performed when shifting to the next half cycle.
It can be stopped once and for all. This is shown in FIG. 1 (b) ((b)).

Also, when a command to stop the motor (▲) is issued at a half cycle when the pulse signal of the sensor circuit is not output, the voltage zero cross coming immediately after that is postponed, and the switching is performed with a slight delay of dt time from the next voltage zero cross. An off signal is applied to the gate of the device. By doing so, the power supply to the motor can be completely stopped when shifting to the next half cycle as before. For this reason, it is possible to accurately measure the cloth amount based on the inertial rotation without energization of the motor.

The dt time is set to be longer than the time when the phase of the current flowing through the motor is the most delayed with respect to the power supply voltage.

FIG. 5 and FIG. 6 show a measuring section of a program for controlling a washing machine according to an embodiment of the present invention.

When the motor is turned on, flg is set to 1 if a sensor input is made between zero crossings (during a half cycle of the power supply), and flg is set to 0 otherwise. When the zero cross pulse is input after the off timing of the on / off pattern set separately, if the flg is 1, the motor is turned off after dt time. flg is 0
If so, wait for the next zero crossing (flg becomes 1 during this time), and turn off the motor after dt time.

〔The invention's effect〕

As described above, according to the present invention, the sensor input is always turned on immediately after the rotation of the motor shifts to the inertial rotation, so that the obtained inter-pulse time correctly reflects the amount of clothing put in.

[Brief description of the drawings]

FIGS. 1 (a) and 1 (b) are signal waveform diagrams, FIG. 2 is a control circuit block diagram of a washing machine, and FIGS.
FIGS. 5 and 6 show a measuring section of a program for controlling a washing machine according to an embodiment of the present invention.

Claims (1)

(57) [Claims] 1. A washing tub, a stirring blade rotatably provided on an inner bottom of the washing tub, a driving motor for stirring and driving the stirring blade and using an AC power supply, and a driving motor. A motor rotation capacitor connected thereto, a forward rotation circuit and a reverse rotation circuit connected to both ends of the motor rotation capacitor and having a switching element such as a triac, and an inertia after the power supply to the drive motor is turned off. A sensor circuit that converts either (positive or negative) half cycle of AC back electromotive force appearing at both ends of the motor rotation capacitor during rotation into a pulse signal and outputs it, and a microcomputer that captures the pulse signal of this sensor circuit And an instruction control unit for measuring the amount of cloth in the washing tub based on the width of the timing of the pre- and post-fetched pulses. When the pulse signal of the sensor circuit is output in a half cycle, when the instruction control unit issues an instruction to stop the energization of the drive motor for measuring the amount of cloth, the AC power supply coming immediately after that. An off signal is added to the switching element by sending it slightly for dt time from the voltage zero cross, and in a half cycle in which the pulse signal of the sensor circuit is not output, the instruction control unit controls the drive motor for measuring the cloth amount. When instructed to turn off the power,
A laundry amount measuring device for a washing machine, wherein an off signal is applied to the switching element with a slight delay of dt time from a voltage zero cross coming immediately after the voltage zero cross coming immediately after the voltage zero cross.