JPH01178288A - Washing machine - Google Patents

Abstract

PURPOSE:To surely detect abnormalities in a semiconductor switching element and enable a measure for safety to be taken by providing a switch element on a power supply bus to which a plurality of loads are connected individually through the semiconductor switching element, while providing a current sensor for detecting current supplied to the power supply bus. CONSTITUTION:It is assumed that in a running process, for example in the dehydrating running, a triac 7 fails and is maintained under the turned-on condition even if the output terminal P2 of a microcomputer 10 is set to the low level. Then, as long as the load current to a dehydrating motor 4 is supplied to a power supply bus 2, it is detected by a current transformer 9 to generate a high level signal from an A/D converting circuit 21. As a result, the output terminal P3 of microcomputer 10 reaches high level to turn on a transistor 24 in a relay driving circuit 23 and supply current to a relay coil 25 for opening a relay switch 8 so that the load current in the power supply bus 2 is immediately shut off. Thus, abnormal exothermic reaction in the dehydrating motor 4 and power supply bus 2 are avoided to ensure safety. Further, an alarm light 19 is flashed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a washing machine in which a plurality of loads such as motors are controlled to be powered on and off through semiconductor switching elements.

(Prior art) In recent years, electric circuits in washing machines have been made into semiconductors, and δ1 is determined based on signals from microcomputers.
A configuration is provided in which a triac, which is a semiconductor switching element, is used to control the energization and disconnection of a dry motor, a dehydration motor, and the like. In this type of washing machine, a microcomputer lights up a display element such as a light emitting diode based on a signal output to a triac for load control, thereby making it possible to check whether operation control is being performed normally or not. There is something like this.

(Problem to be Solved by the Invention) In this type of washing machine, if the triac for controlling the dehydrating motor fails while the dehydrating basket is restrained by the brake, the motor continues to be energized. If this happens, the motor will overheat, and in the worst case scenario, there is a risk of a fire.

Therefore, for safety, it is necessary to reliably detect any abnormality in the semiconductor switching element and take prompt action. However, the above configuration has a drawback in that although it is possible to determine whether the microcomputer malfunctions or the chip is defective, it is impossible to detect any abnormality in the semiconductor switching element □ for load control.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a washing machine that can reliably detect abnormalities in semiconductor switching elements and take safety measures.

[Structure of the Invention] (Means for Solving the Problems) The washing machine of the present invention includes a switch element on a power bus to which a plurality of loads are connected via separate semiconductor switching elements, and a current flowing through the power bus. A current sensor is provided to detect the load, and when the current sensor detects a current flowing to the load when the microcomputer is not outputting a drive signal for the load, the switch element is opened and the abnormality notification means is activated. It is characterized by the fact that it is

(Function) In the unlikely event that the semiconductor switching element for load control fails,
If a load current flows even though the microcomputer is not outputting a load driving signal, this current is detected by a current sensor provided on the power supply bus. Then, the microcomputer opens the switch element of the power supply bus and activates the abnormality notification means. As a result, the negative current of the power supply bus is cut off, and overheating of the load and power circuit is avoided, and the user can be notified of the occurrence of an abnormality by the abnormality notification means, so that repairs, etc. It becomes possible to take appropriate measures. In addition, since the current sensor for detecting abnormal current is installed on the power supply bus that commonly supplies power to multiple loads, it is possible to detect abnormalities in multiple semiconductor switching elements with a single current sensor. Can be done.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

1 is a commercial power supply, 2 and 2 are a common power supply bus for supplying power to multiple loads from this commercial power supply 1, 3 is a washing motor that can be rotated in forward and reverse directions as a load, and 4 is a dewatering motor that is also a load. . The forward rotation terminal 3a and reverse rotation terminal 3b of the washing motor 3 and the terminal 4a of the dehydration motor 4 are each connected to triacs 5, 6.7 which are three semiconductor switching elements.
It is connected to the power supply bus 2 via. 8 is power bus 2
9 is a relay switch which is a switch element provided in , and 9 is a current transformer which is a current sensor.

On the other hand, 10 is a microcomputer that constitutes an operation control circuit for controlling the load group and executing each process such as washing and dehydration. A self-diagnosis program shown in FIG. 3, which functions as described later, is incorporated. 11 is a clock signal generation circuit, 12 is an initialization circuit, and 13 is a waveform shaping circuit. Reference numeral 14 denotes an operation circuit, which includes a group of keys 16 arranged on an operation panel 15 (see FIG. 2) for selecting and setting strokes and for starting and stopping them. Reference numeral 17 denotes a display circuit, which includes a plurality of light emitting diodes 18 provided on the operation panel 15 to display the contents selected and set by the keys 16, and a warning light corresponding to an abnormality notification means constituted by the light emitting diodes. 19
including.

20 is the output terminal Po-P of the microcomputer 10
Three driving transistors connected to the triacs 5 to 7 are turned on when the respective output terminals Po to P2 become high level, turning on the triacs 5 to 7. 21 is A
/D conversion circuit, the analog input terminal of which is connected to the current transformer 9.
When the load current flowing to the power supply bus 2 is detected by the current transformer 9, a high level signal is sent to the input terminal P4 of the microcomputer 10. Output. 23 is a relay drive circuit, which operates transistor 2 when the output terminal P3 of the microcomputer 10 becomes high level.
4 is turned on, the relay coil 25 is energized, thereby opening the relay switch 8.

Next, the operation of this embodiment will be explained.

By operating the process selection keys 16 on the operation panel 15 to set, for example, the execution time of the washing process, water flow strength, and execution time of the dehydration process, and further operating the start/stop keys 16, the washing process starts. will be started. Then, the output terminals Po and Pl of the microcomputer 10 alternately become high level, and the triacs 5 and 6 are alternately turned on.

As a result, the washing motor 3 repeats forward and reverse rotation, and the clothes are washed in the washing tub. Then, when the set time elapses and the washing process ends, the output terminal P. and P
l becomes a low level, and the output terminal P2 becomes a high level instead, turning on the triac 7. This results in
The dehydration motor 4 is driven to start the dehydration operation, and the dehydration operation ends after a set time has elapsed.

Now, in the following operation process, for example, the triac 7 fails during the dehydration operation, and even though the output terminal P2 of the microcomputer 10 becomes low level, the triac 7 remains on. Suppose that it is maintained at In this embodiment, in such a case, as long as the load current to the dehydration motor 4 is flowing through the power supply bus 2, this is detected by the current transformer 9 and a high level signal is output from the A/D conversion circuit 21. Ru. Since the microcomputer 10 has a built-in self-diagnosis program as shown in FIG. 3, when the output terminal P becomes low level, the determination step a becomes "NO", and then the load current is detected. Since the output of the A/D conversion circuit 21 is at a high level, the result is "Yes" in the determination step b. As a result, the output terminal P3 of the microcomputer 10 becomes high level, the transistor 24 of the relay drive circuit 23 is turned on, the relay coil 25 is energized, and the relay switch 8 is opened, so that the load current of the power supply bus 2 is reduced. It will be immediately blocked. This ensures safety by avoiding abnormal heat generation in the dehydration motor 4 and power bus 2 due to the user opening the lid of the dehydration tank without knowing that an abnormality has occurred and applying a brake to the dehydration basket. Furthermore,
At the same time, as shown in step d, the warning light 19 of the display circuit 17 flashes to notify the user of an abnormality, so the user can see this and know that there is an abnormality and the operation has stopped. Appropriate measures such as requesting repairs can be taken.

According to this embodiment, when an abnormality occurs in the triacs 5 to 7 that control the energization and disconnection of the motors 3 and 4, the relay switch 8 is immediately opened to cut off the abnormal current. It is possible to prevent dangerous situations such as abnormal overheating and ignition of the power supply bus 2. In addition, as described above, in addition to cutting off abnormal current, the warning light 1
9, the user can take appropriate measures such as repair. Moreover, even though it is intended to monitor abnormalities in a 1U triac, it only requires the addition of a current transformer RR9 and a relay switch 8, etc. in terms of hardware, so it does not increase the cost by 1-1. do not have. Furthermore, recent washing machines detect the load current of the washing motor, detect the load of clothes, etc. based on this, and use a microcomputer to perform appropriate operation control according to the load. Since it is possible to use the same current sensor for both operation control and abnormality detection, it is possible to minimize the cost increase due to changes in hardware and to deal with it only by changing the software.

In the embodiment described in 2, a case where power is supplied to the washing motor 3 and the dehydration motor 4 from the common power supply bus 2 is explained, but in addition, the common power supply bus is also supplied to valve devices such as water supply valves and brake solenoids. The present invention can also be applied to a washing machine configured to supply power from. In addition, a semiconductor switching element may be provided in place of a relay switch, a buzzer may be provided in place of or in addition to the warning light 19 as an abnormality notification means, and a semiconductor current sensor using a Hall element may be provided in place of a current transformer. The present invention is not limited to the embodiments described above and shown in the drawings, but can be implemented with various modifications without departing from the scope of the invention.

[Effects of the Invention] As mentioned above, in the washing machine of the present invention, when a load current flows to the power supply bus even though the microcomputer does not output a signal for driving the load, the The current sensor detects this and opens the switch element provided on the power bus, and also activates the abnormality notification means, so that any abnormality in the semiconductor switching element that controls the energization and disconnection of the load can be immediately detected. It is able to prevent dangerous situations such as load overheating and fire, and it has the excellent effect of being able to achieve this with an extremely simple configuration even though it monitors multiple targets. be.

[Brief explanation of the drawing]

The drawings show one embodiment of the present invention, and FIG. 1 is an electric circuit diagram;
FIG. 2 is a front view of the operation panel, and FIG. 3 is a flowchart. In the drawing, 2 is a power bus, 3 is a washing motor (load), 4 is a dehydration motor (load), 5.6.7 is a triac (semiconductor switching element), 8 is a relay switch (switch element), and 9 is a current transformer. (current sensor), 10 is a microcomputer, and 119 is a warning light (anomaly notification means). Applicant: Toshiba Corporation Toshiba Audio/Video Engineering Co., Ltd. Figure 2 Figure 3

Claims (1)

[Claims] 1. In a device in which a plurality of loads are connected to a common power supply bus through separate semiconductor switching elements, and these semiconductor switching elements are controlled to open and close by an operation control circuit equipped with a microcomputer, A switch element is provided as well as a current sensor that detects the current flowing through the power supply bus, and when the current sensor detects the current flowing through the load when the microcomputer is not outputting a drive signal for the load, the switch is activated. A washing machine characterized in that an abnormality notification means is activated when the element is opened.