JPS6355319B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a motor control device that can be used regardless of whether the frequency of the commercial power source is 50Hz or 60Hz. It is something that brings out its characteristics. In particular, when the present invention is applied to motor control in a washing machine, its effects can be dramatically enhanced.

Conventionally, washing machines have used the same motor even in regions with different power supply frequencies. Therefore, a difference in the power supply frequency directly results in a difference in the rotational speed of the motor, and if washing, rinsing, dehydration, etc. are performed using this motor, there will be differences in the performance of washing, rinsing, and dehydration.

Therefore, it has been proposed to replace the motor pulley in order to change the diameter of the pulley, but this replacement work is time-consuming and also poses problems such as complicating parts management during assembly. had.

The present invention is capable of preventing changes in motor characteristics due to differences in power supply frequency using the same motor control device, and embodiments thereof will be described below. FIG. 1 shows the basic configuration of the control device. Reference numeral 1 denotes a power synchronization signal generation circuit that generates a pulse signal in synchronization with the zero phase of a commercial power source, and its output is input to a counting section 2. The counting section counts the number of times the pulse signal is input, and outputs an output signal of the same sign until the counted value reaches the first set value, and when the counted value becomes equal to or greater than the first set value, the second set value is reached. The count value is outputted with a different sign from the output signal until it reaches (>the first set value), and when it reaches the second set value or more, the count value is reset to O again. The output of the counting section 2 is input to a synthesis section 3, and the output of the timer section 4 is also input to this synthesis section 3. The timer unit 4 outputs an output for a certain period of time from the start of the motor, and
The synthesis section 3 outputs a constant signal when the timer section 4 is outputting the signal, and prohibits the output signal from the counting section 2 from being output. Then, when the output from the timer section 4 disappears, the synthesis section 3 outputs the output signal of the counting section 2. That is, at startup, the output signal from the counting section, which is the basis of motor energization control, is not output, but a constant signal is output to keep the motor in a fully energized state, allowing the motor to smoothly ramp up the rotational speed at startup.

The output of the synthesis section 3 and the output of the power supply frequency discrimination section 6 are input to the discrimination circuit 5 . In the discrimination circuit 5,
Based on the output instruction from the power frequency discrimination section 6, the synthesis section 3
It is determined whether to output an output of , or a constant output, and use that output. The output of this discrimination circuit 5 is input to a motor drive unit 7, and this output controls a motor 8. That is, if the output from the discrimination circuit 5 is a constant output, the motor 8 is energized during the output, and when the output signal from the counting section 2 is output from the discrimination circuit 5, the output signal with the same sign is The motor 8 is energized at the time of output, and the energization to the motor 8 is stopped at the time of output with a different sign.

To further explain the case where the above motor control device is applied to a washing machine, in the discriminator circuit 5, when using 50Hz, the power frequency discriminator 6
The output is always outputted to operate the motor drive section 7, and when using 60Hz, the output signal from the counting section 2 is outputted via the synthesis section 3 (if there is no output from the timer section 4) and the discrimination circuit 5. ,as a result,
To make the rotational characteristics of a motor the same even if there is a difference in the commercial power supply frequency used.

Fig. 2 shows the energization waveform to the motor 8 in the 60Hz area.The counting section 2 is composed of an octal counter, and when the count value of this counter reaches "7", it is output to the synthesis section 3, and as a result, the motor 8 is operated, and when the count value reaches "8", the output is stopped, and when the count value reaches "9", the output is reset.
That is, in this example, in order to turn off the power to the motor 8 when the count value is "8", the rotational force of the motor 8 is weakened, and when the count value is 60Hz, the rotation speed of the motor 8 is kept lower than usual by the above output. Since it is fully energized with constant output at 50Hz, the normal rotation speed of 50Hz is obtained, and as a result, 50Hz,
The motor characteristics at 60Hz are the same. of course
The conduction state at 60 Hz is determined by the motor 8, and the fact that the counting section 2 is configured with an octal counter is not a limiting factor of the present invention.

FIG. 3 shows a specific circuit example based on the conditions shown in FIG. That is, 9 is a commercial power supply, 10 is a transformer that steps down the output, 11 is a full-wave rectifier diode bridge, 12 and 13 are resistors that divide the output of this bridge 11, and the divided voltage is the voltage of the transistor 14. The transistor 14 is added to the base, becomes non-conductive except near the zero phase of the power supply waveform, and is inputted to the counting section 2 via the resistor 15.

The counting section 2 mainly consists of an octal counter 16, the output of which is input to an OR gate 17.
The output of OR gate 17 is when the count value is “7” or less.
becomes HIGH (VDD). And the count value is “8”
The output will be LOW (grounded) only when . This output is input to a combining section 3 made up of NAND. The output of the timer section 4 is also input to the synthesis section 3 .

The timer section 4 consists of a monostable multi 18, a resistor 19 that determines its inversion time, and a capacitor 20. At startup, its output becomes HIGH for a certain period of time determined by the resistor 19 and capacitor 20. Therefore, the output of the synthesis section 3 becomes HIGH due to the output of the timer section 4 at startup, and then the output of the counting section 2 becomes HIGH.
Due to the output of , only “7/8” becomes HIGH. This output is input to a discrimination circuit 5 consisting of NAND.
Further, the output of the power supply frequency discriminator 6 is also input to the discrimination circuit 5 .

In this embodiment, the discrimination circuit 5 includes a resistor 21 and a switch 22. When the commercial power supply is 50 Hz, the switch 22 is closed and its output becomes LOW. Of course, an automatic frequency switching circuit may be used as the power supply frequency determining section 6.

Therefore, the output of the discrimination circuit 5 is always HIGH at 50 Hz, and HIGH at 60 Hz for a time determined by the synthesizing section 3, and is input to the motor driving section 7.

In the motor drive section 7, the output of the discrimination circuit 5 is
When HIGH, transistor 2 is connected via resistor 23.
4 conducts, and the output of transistor 24 is connected to resistor 2
5, the bidirectional semiconductor switch element 26 is made conductive, thereby operating the motor 8. 27 is a diode, 28 is an electrolytic capacitor, and constitutes a DC power supply.

In the above embodiment, the motor 8 is continuously energized at 50Hz, is energized for the period specified by the counter 2 at 60Hz, and is partially damped by the DC component, so that even if the commercial power supply frequency differs, the characteristics of the motor 8 remain unchanged. be the same.

Note that the counting section 2, synthesis section 3, timer section 4, and discrimination circuit 5 in the above embodiment can be constructed by a microcomputer, and the same effects as in this embodiment can also be obtained by this.

Furthermore, it goes without saying that the present invention can be implemented in devices other than washing machines, such as dryers, dishwashers, etc.

As described above, according to the present invention, the motor exhibits the same characteristics regardless of whether the commercial power frequency is 50 Hz or 60 Hz. Its industrial value is extremely large, as it does not require complicated pulley replacement work or complicated parts management, and can significantly reduce man-hours and costs.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a motor control device according to an embodiment of the present invention, FIG. 2 is a diagram showing a waveform of current applied to the motor at 60 Hz, and FIG. 3 is a specific electric circuit diagram of the same control device. 1... Power synchronization signal generation circuit, 2... Counting section,
5...Discrimination circuit, 6...Power frequency discrimination unit, 7...
...Motor drive unit, 8...Motor, 9...AC power supply.

Claims (1)

[Claims] 1 A power synchronization signal generation circuit that generates a signal in synchronization with the zero phase of the power supply of a commercial power source, and a power supply synchronization signal generation circuit that counts the number of times the signal is input and outputs a signal of the same sign until the counted value reaches a first set value. and outputs a signal having a different sign from the signal having the same sign until the count exceeds a first set value and reaches a second set value, and resets the counted value when the count exceeds the second set value. A discrimination circuit that selects and outputs the output of the counting section or a constant output based on the output of the power frequency discrimination section, and energizes the motor when the output of the discrimination circuit is a constant output or an output of the same sign, and outputs the output of the same sign. A motor control device equipped with a motor drive section that stops energizing the motor when the output has a sign different from that of the motor.