KR19990031048A - Safety device of discharge circuit for braking of washing machine - Google Patents

Abstract

The present invention relates to a discharge circuit for braking a washing machine, and more particularly, to a safety device of a discharge circuit capable of suppressing damage to a device of the discharge circuit by an abnormal voltage.

The safety device of the discharge circuit for braking the washing machine includes: a discharge circuit of a washing machine for discharging electric energy generated when braking the motor, the power switch for opening and closing a current path supplied to the motor; Comparing means for comparing a voltage generated during braking of the motor with a reference voltage; Switching means for switching by the output of said comparing means to discharge electrical energy generated when braking the motor; When the discharge operation is performed by the switching operation of the switching means, it characterized in that it comprises a temperature sensing means for sensing the temperature of the discharge current, and controlling the operation of the power switch when detecting the abnormal current.

Description

Safety device of discharge circuit for braking of washing machine

The present invention relates to a discharge circuit for braking a washing machine, and more particularly, to a safety device of a discharge circuit capable of suppressing damage to a device of the discharge circuit by an abnormal voltage.

In general washing machines, when laundry and an appropriate amount of water are supplied to a washing tank, a brushless DC motor operates to wash the pulsator in the washing tank while rotating the motor forward or reverse. When the washing is completed, the dirty water is drained, and when the draining is completed, the brushless DC motor rotates the washing tank itself to dehydrate the washing tank.

This washing process is largely divided into washing process, rinsing and dehydration process. At this time, in the washing process and the rinsing process, only the pulsator in the washing tank rotates forward or reverse, and since the rotating speed is not a very high speed, there is no great risk even if the users open the lid of the washing machine. However, in the dehydration process, as the washing tank itself rotates, the rotation speed becomes very high. Therefore, when the user inadvertently opens the lid of the washing machine or selects the 'stop' button during this dehydration process, the washing tank is stopped rapidly to prevent danger.

When the washing tank is stopped in a hurry, the driving of the motor is stopped by flowing a current in a direction opposite to the rotational direction of the motor. In this case, the inertial energy of the washing tank is discharged to the ground potential.

Next, the discharge process during braking of the washing machine will be described in more detail with reference to the related art.

1 is a block diagram showing the configuration of a brushless DC motor control circuit of a general washing machine.

Looking at the configuration, the filter unit (1) for filtering and outputting the AC power input to a predetermined value, the rectifier (3) for rectifying the voltage through the filter unit 1 to the DC voltage, the capacitor (C1) and the resistor A smoothing part 5 composed of (R1, R2) to smooth the output voltage of the rectifying part 3, and transistors TR1 to TR6 and diodes D1 to D6, and the smoothing part 5 Inverter unit 7 for converting the DC power transmitted from the three-phase AC power to the reverse conversion to the brushless DC motor (hereinafter referred to as "motor": 9).

Then, the amount of current flowing through the resistor R13 connected to the rear end of the smoothing unit 5 is detected, the amount of current flowing through the inverter unit 7 is monitored, and the damage of the motor 9 due to overcurrent and And an overcurrent protection unit 11 for preventing damage to each circuit element.

The signal detected by the overcurrent protection unit 11 is input to the microprocessor 13, and the microprocessor 13 receives a gate driver 15 and a motor (for driving the inverter unit 7) by the detection signal. 9) to control the operation. The gate driver 15 described above controls the operation of the transistors TR1 to TR6 included in the inverter unit 7 under the operation control of the microprocessor 13.

In addition, a position sensor 17 for detecting a rotational position of the motor by converting a signal generated from a hall sensor (position sensor: hall sensor) attached to the motor to a logic signal, the position detection unit 17 The position signal detected at) is input to the microprocessor 13.

When the motor 9 is braked under the control of the microprocessor 13, a current must flow in a direction opposite to the rotation direction of the motor 9, wherein electric energy of the washing tank is transferred to the inverter unit 7. The capacitor C1 is charged through the diodes D1 to D6. And a discharge unit 19 for discharging the voltage at a ground potential when the voltage across the capacitor C1 becomes above a certain level.

FIG. 2 is a detailed circuit diagram of the discharge unit 19 shown in FIG. 1 and shows a discharge circuit diagram for braking a washing machine according to the prior art.

Looking at the connection relationship, the discharge unit 19 for flowing the electric energy generated during braking of the washing machine to the ground potential is connected between the smoothing unit 5 and the inverter unit (7).

The voltage across the capacitor C1 is input to the inverting terminal through the resistors R1 and R2, and is input to the inverting terminal as the reference voltage determined by the resistors R3 and R4 coupling the +15 volt power supply in series. The comparator 21 outputs a logic signal according to the difference signal between the two input signals. And the comparator 21 is discharged. In order to make the start voltage high and the discharge end voltage low, the output terminal and the inverting terminal are connected through the resistor R5.

A gate drive 23 for controlling the operation of the transistor Q1 connected to the rear end by inputting the output signal of the comparator 21 and a signal output from the gate drive 23 to be turned on or off. The transistor Q1 is operated, and the resistor R6 causes a voltage flowing across the capacitor C1 to flow at a base potential during the turn-on operation of the transistor Q1.

Next, an operation process during braking of the washing machine according to the above configuration will be described in detail with reference to FIGS. 1 and 2.

When the user puts laundry into the washing tank and applies AC power, the input AC power is filtered by the filter unit 1 and rectified by the rectifying unit 3 to DC power. The rectified DC power is output after the noise signal is removed from the smoothing section 5.

In this way, the power output from the smoothing part 5 is applied to the inverter part 7, and makes it the state for driving the motor 9. As shown in FIG.

Meanwhile, the microprocessor 13 determines whether the washing machine is a washing process, a rinsing process, or a dehydration process, and performs an operation according to each process.

That is, when the washing machine performs washing by washing or rinsing, the microprocessor 13 applies a driving signal to the gate driving unit 15, and the gate driving unit 15 of the inverter unit 7 is driven by the signal. The control signal is supplied to the base terminal of each transistor.

Then, the inverter unit 7 is driven by the control signal applied from the gate driver 15 to invert the DC power output from the smoothing unit 5 to a three-phase AC power to supply the motor 9. . The motor 9 is driven by a three-phase AC power source to perform washing or rinsing while rotating the pulsator in the washing tank in the forward or reverse direction.

On the other hand, the voltage flowing across the capacitor (C1) of the smoothing unit 5 is input to the inverting terminal of the comparator 21, the comparator 21 is a reference for inputting the voltage input to the inverting terminal as a non-inverting terminal A signal corresponding to the difference signal is output in comparison with the voltage.

However, since the motor 9 does not rotate at high speed in the washing process or the rinsing process of the washing machine, the voltage input to the inverting terminal of the comparator 21 is smaller than the reference voltage. In this case, since the voltage output from the smoothing part 5 is mostly supplied to the motor 9 through the inverter part 7, the voltage flowing across the capacitor C1 is input to compare with the reference signal. The output of the comparator 21 goes low.

At this time, the output low signal is not sufficient to turn on the transistor Q1, so that there is no current flowing to the base potential through the discharge unit 19.

Next, after the washing is completed, if the washed and dirty water is drained to some extent, the microprocessor 13 proceeds to the dehydration of the laundry in the following process.

In the dehydration process, the washing tank itself rotates, so that the motor 9 rotates at a very high speed. Therefore, if the user opens the lid of the washing machine or inputs a 'stop' command during the dehydration process, the microprocessor 13 sends a current to the motor 9 in a direction opposite to the current rotational direction. (9) will be suddenly stopped.

In more detail, the process outputs a control signal according to the braking of the motor 9 from the microprocessor 13 to the gate driver 15, and the gate driver 15 is a switching device of the inverter unit 7. Turn off (TR1 to TR6).

At this time, the current output from the smoothing unit 5 is charged in the capacitor C1 through the diodes D1 to D6 of the inverter unit 7. In this way, the voltage across the capacitor C1 rises, and this voltage is input to the inverting terminal of the comparator 21 through the resistor.

The comparator 21 outputs a high signal when the voltage across the capacitor C1 is higher than the reference voltage. At this time, the high signal output is input to the base terminal of the transistor Q1 after signal compensation is performed in the gate drive 23.

Transistor Q1 is thus turned on by this voltage, causing the voltage across the capacitor C1 to flow at ground potential.

That is, the discharge circuit driven during braking of the conventional washing machine, when the DC link voltage that is the voltage across the capacitor (C1) is greater than the reference voltage in the comparator 21, that is, the electrical energy that the washing tank has during rapid braking Is flowing at base potential.

On the other hand, the voltage input to the comparator 21 of the discharge circuit during braking is a very large voltage. This is because the washing tank itself is rotated at a high speed during the dehydration process, because a very high voltage is applied to the motor 9, and the electrical energy generated thereby is also very large.

Therefore, the comparator 21, which is designed to input the high voltage and compare it with the reference signal, is able to withstand a certain amount of overvoltage. When the input overvoltage is larger than the reference voltage compared with the reference voltage, the comparator 21 outputs a high signal and drives the gate drive 23.

However, due to the overvoltage, when the discharge circuit is operated by outputting a high signal from the comparator 21, there is a concern that the circuit element including the gate drive 23 is damaged. This is because the gate drive 23 is configured to be driven only by the output of the comparator 21.

Accordingly, an object of the present invention is to provide a safety device for a discharge circuit for braking a washing machine that can suppress the operation of the discharge circuit in the overvoltage region.

1 is a block diagram showing the configuration of a brushless DC motor control apparatus of a general washing machine;

Figure 2 is a detailed circuit diagram of the discharge circuit shown in Figure 1, a discharge circuit diagram for braking the washing machine according to the prior art,

3 is a circuit diagram showing a safety device of a discharge circuit for braking a washing machine according to a first embodiment of the present invention;

4 is a circuit diagram showing a safety device of a discharge circuit for braking a washing machine according to a second embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

1: filter part 3: rectifier part

5: smooth part 7: inverter part

9: brushless DC motor 11: overcurrent protection

13, 50: microprocessor 15: gate driver

17: position detection unit 19, 40: discharge circuit

21, 42: comparators 23, 44: gate drive

C1, C2: Capacitor 45: Temperature sensing part

R1 to R15: resistors Q1, Q2 and TR1 to TR6: transistors

D1 ~ D6: Diode SW: Power Switch

Safety device of the discharge circuit for braking the washing machine according to the first embodiment of the present invention for achieving the above object, in the discharge circuit of the washing machine for discharging the electrical energy generated during braking of the motor, generated during braking of the motor Comparing means for comparing the applied voltage with a reference voltage; A gate drive inputting control means for outputting a control signal for operation of the discharge circuit during braking of the motor, an output signal of the comparing means and a control signal of the control means, and driving when two signals are satisfied; Switching by the output of the gate drive, characterized in that it comprises a switching means for discharging the electrical energy generated during braking of the motor.

Safety device of the discharge circuit for braking the washing machine according to the second embodiment of the present invention for achieving the above object, the current supplied to the motor in the discharge circuit of the washing machine to discharge the electrical energy generated when the motor braking A power switch for opening and closing the passage; Comparing means for comparing a voltage generated during braking of the motor with a reference voltage; Switching means for switching by the output of said comparing means to discharge electrical energy generated when braking the motor; When the discharge operation is performed by the switching operation of the switching means, it characterized in that it comprises a temperature sensing means for sensing the temperature of the discharge current, and controlling the operation of the power switch when detecting the abnormal current.

The discharge circuit safety device according to the first embodiment of the present invention is a power device for discharging when a microprocessor combines an operation signal of a discharge circuit and a discharge signal by judgment of the discharge circuit itself, and both signals are desired to be discharged. Characterized in that to perform the operation of.

In particular, the operation signal of the discharge circuit in the microprocessor is characterized in that is generated when the electrical braking during the washing process of the washing machine.

The safety device of the discharge circuit according to the second embodiment of the present invention is characterized in that when the discharge operation of the discharge circuit is performed, the temperature of the discharge resistor is sensed, and when the abnormal voltage, the input power is cut off.

The discharge circuit safety device of the present invention as described above suppresses the operation of the power device for discharging caused by the operation of the discharge circuit in the above overvoltage region, thereby preventing damage to the circuit elements and bringing reliability to the operation of the discharge circuit. It has an effect.

Hereinafter, a safety device of a discharge circuit for braking a washing machine according to the present invention will be described in more detail with reference to the accompanying drawings.

3 is a circuit diagram illustrating a safety device of a discharge circuit for braking a washing machine according to a first embodiment of the present invention. And necessary parts in the configuration of the brushless DC motor control device of the washing machine will be described with reference to FIG.

First, the safety device of the discharge circuit for braking the washing machine of the present invention describes the connection relationship.

The voltage across the capacitor C1 is input to the inverting terminal through the resistors R1 and R2, and the reference voltage determined by the resistors R7 and R15 coupled in series is input to the non-inverting terminal. Comparator 42 for outputting a logic signal according to the difference signal is included. The comparator 42 is connected in parallel with a resistor R9 and a capacitor C2 between the output terminal and the non-inverting terminal in order to have a high discharge start voltage and a low discharge end voltage.

A gate drive 44 for controlling the operation of the transistor Q2 connected to the rear end by inputting the output signal of the comparator 42 and the operation signal of the discharge circuit from the microprocessor 50, and the gate drive 44. Transistor Q2 which is turned on or off by a signal output from the transistor and a resistor which flows a voltage flowing across the capacitor C1 at a base potential during turn-on operation of the transistor Q2. It comprises a (R9).

The following describes the safety device operation of the discharge circuit according to the first embodiment of the present invention.

When the user puts laundry into the washing tank and applies AC power, the input AC power is filtered by the filter unit 1 and rectified by the rectifying unit 3 to DC power. The rectified DC power is smoothed and output from the smoothing unit 5. In this way, the power output from the smoothing part 5 is applied to the inverter part 7 through the discharge circuit 40, and makes it the state for driving the motor 9. As shown in FIG.

Meanwhile, the microprocessor 50 determines whether the washing machine is a washing process, a rinsing process, or a dehydration process, and performs an operation according to each process.

That is, when the washing machine performs the washing by the washing or the rinsing process, the microprocessor 50 applies the driving signal to the gate driving unit 15, and the gate driving unit 15 of the inverter unit 7 generates the driving signal. The control signal is supplied to the base terminal of each transistor.

Then, the inverter unit 7 is driven by the control signal applied from the gate driver 15 to invert the DC power output from the smoothing unit 5 to a three-phase AC power to supply the motor 9. . The motor 9 is driven by a three-phase AC power source to perform washing or rinsing while rotating the pulsator in the washing tank in the forward or reverse direction.

That is, in the process of supplying power to the motor 9 through the inverter unit 7 by the gate driver 15, the control signal for the operation of the discharge circuit is not applied to the gate drive 44. do. In other words, the operation of the discharge circuit 40 is in a suppressed state.

Of course, even in this state, the voltage flowing across the capacitor C1 of the smoothing part 5 is input to the inverting terminal of the comparator 42, and the comparator 42 converts the voltage input to the inverting terminal into the non-inverting terminal. A signal corresponding to the difference signal is output in comparison with the input reference voltage.

However, since the motor 9 does not rotate at high speed in the washing process or the rinsing process of the washing machine, the voltage input to the inverting terminal of the comparator 42 is smaller than the reference voltage. In this case, since the voltage output from the smoothing part 5 is mostly supplied to the motor 9 through the inverter part 7, the voltage flowing across the capacitor C1 is input to compare with the reference signal. The output of the comparator 42 goes low.

Thus, there is no current flowing through the discharge circuit 40 to the ground potential.

Next, after washing is completed, if the washed and dirty water is drained to some extent, the microprocessor 50 proceeds to dewater the laundry in the following process.

In the dehydration process, the washing tank itself rotates, so that the motor 9 rotates at a very high speed. Therefore, when the user opens the lid of the washing machine or inputs a 'stop' command during the dehydration process, the microprocessor 50 causes the motor 9 to flow a current in a direction opposite to the current rotational direction. (9) will be suddenly stopped.

In more detail, the microprocessor 50 outputs a control signal according to the braking of the motor 9 from the microprocessor 50 to the gate driver 15, and the gate driver 15 is a switching device of each inverter unit 7. Turn off (TR1 to TR6). In addition, the microprocessor 50 outputs a control signal for the operation of the discharge circuit to the gate drive 44 of the discharge circuit (40).

At this time, the current output from the smoothing unit 5 is charged in the capacitor C1 through the diodes D1 to D6 of the inverter unit 7. In this way, the voltage across the capacitor C1 rises, and this voltage is input to the inverting terminal of the comparator 42 through the resistor. The comparator 42 outputs a high signal when the voltage across the capacitor C2 is higher than the reference voltage.

On the other hand, since the gate drive 44 inputs the control signal according to the operation of the discharge circuit from the microprocessor 50 from another input terminal, the gate drive 44 compensates for the high signal input from the comparator 42 and the transistor Q2. Output to the base terminal of).

In this way, the transistor Q2 is turned on to cause the voltage flowing across the capacitor C1 applied through the resistor R9 to flow to the ground potential.

Next, when the voltage flows into the discharge circuit 40 through the smoothing part 5 of the overvoltage, the comparator 42 generates a high voltage when the voltage of the inverting terminal of the comparator 42 is higher than the reference voltage of the non-inverting terminal. The signal is output, but at this time, since the operation control signal of the discharge circuit according to the electric braking operation is not input from the microprocessor 50 to the gate drive 44, the gate drive 44 does not operate.

When the gate drive 44 is not operated, the electrical influence is not exerted on the circuit elements of the rear stage including the gate drive 44, and therefore, the occurrence of malfunction due to the overvoltage can be suppressed.

4 is a circuit diagram illustrating a safety device of a discharge circuit for braking a washing machine according to a second embodiment of the present invention.

Since the configuration is almost the same as in FIG. 3, when only different parts are considered, the power switch SW is included between the rectifying section 3 and the smoothing section 5. The on / off control operation of the power switch SW further includes a temperature sensing unit 45 for sensing a temperature of the discharge resistor R9 and turning off the power switch SW when an abnormal overvoltage flows. do.

In FIG. 3, the discharge circuit operation signal applied during braking from the microprocessor 50 is not input in FIG. 4.

The safety device operation of the discharge circuit according to the above configuration is performed as follows.

During the braking operation of the washing machine, the voltage across the capacitor C1 rises, and this voltage is input to the inverting terminal of the comparator 42 through the resistor. The comparator 42 outputs a high signal when the voltage across the capacitor C1 is higher than the reference voltage.

The high signal output from the comparator 42 drives the gate drive 44. At this time, the gate drive 44 turns on the transistor Q2 while outputting the high signal. When the transistor Q2 is turned on, the voltage flowing across the capacitor C1 applied through the resistor R9 flows to the base potential through the collector-emitter terminal of the transistor Q2.

In this way, the discharge circuit 40 operates to discharge to ground through the resistor R9 and the transistor Q2, and at this time, the temperature sensing unit 45 senses the temperature of the resistor R9. do.

If an abnormal voltage is input and the temperature of the discharge resistor R9 rises, the temperature detecting part 45 turns off the power switch SW connected to the rear end of the rectifying part 3.

When the power switch SW is turned off, the current path is cut off as a result, thereby preventing damage to the circuit element due to the abnormal power supply.

As mentioned above, this invention is demonstrated and this invention is not limited to what was demonstrated above, It can also be implemented with the following forms.

That is, the discharge resistor R9 may be installed at a temperature fuse at which the rising temperature is sensed during the discharge operation of the discharge resistor R9 and the fuse is cut off at the abnormal voltage. That is, during the discharge operation, an abnormal voltage may be input to the discharge resistor R9, and the current fuse may be lost while the temperature fuse is sensed.

As described above, the discharge circuit safety device driven during braking of the washing machine according to the present invention is driven at an abnormal overvoltage by sensing the rising temperature of the discharge resistance or operating the discharge circuit only during the braking operation by the control of the microprocessor. There is an advantage that it is possible to prevent the damage of the electrical circuit elements caused by the reliability of the discharge operation.

In addition, the safety device of the discharge circuit driven during braking of the washing machine according to the present invention, there is an effect that can prevent the failure of the motor control circuit part due to the disconnection of the pattern fuse (fattem fuse) and the temperature fuse during the over-voltage.

Claims (3)

In the discharge circuit of the washing machine for discharging the electric energy generated when the motor braking, Comparing means for comparing a voltage generated during braking of the motor with a reference voltage; Control means for outputting a control signal for operating the discharge circuit when braking the motor; A gate drive which inputs an output signal of the comparison means and a control signal of the control means and is driven when the two signals are satisfied; And a switching means for switching by an output of the gate drive to discharge electric energy generated when the motor is braked. In the discharge circuit of the washing machine for discharging the electric energy generated when the motor braking, A power switch for opening and closing a current path supplied to the motor; Comparing means for comparing a voltage generated during braking of the motor with a reference voltage; Switching means for switching by the output of said comparing means to discharge electrical energy generated when braking the motor; A discharge circuit driven during braking of a washing machine comprising a temperature sensing means for sensing a temperature of a discharge current when a discharge operation is performed by a switching operation of the switching means and controlling an operation of the power switch when an abnormal current is sensed Safety device. The method of claim 2, When the discharge operation is made by the switching operation of the switching means, further comprising a discharge resistor for guiding the discharge current to the switching means, The temperature sensing means is a safety device of a discharge circuit driven during braking of the washing machine, characterized in that for sensing the rising temperature of the discharge resistance.