JPS6311919B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a washing machine drive system, in particular a frequency conversion drive system, and provides an efficient acceleration method for a rotating body (washing machine) having a resonance point. The present invention also relates to a washing machine drive method related to a frequency conversion drive method control method that prevents excessive vibration of the device.

Conventional frequency conversion drive systems are mainly used in industrial equipment, and their control methods are also large-scale.
It's expensive.

As a variable speed drive system, such a drive system allows the rotation speed to be set freely when driving rotating equipment, and has a great advantage over gear shifting and the like.

Especially, the whirlpool type fully automatic washing machine in the domestic market,
Since drum-type washing machines in Western Europe require a plurality of set rotational speeds, this effect is remarkable, and various applications of the drive system are being studied.

This drive method uses the rotation speed of the drive motor as Nrpm,
The set frequency is Hz, the slip is s, the number of poles is P, the terminal voltage is V volts, the magnetic flux density is φ, and the torque is T.
When Kg-cm, the following relationship holds true.

N=120(1-s)/P ……(1) φ=K・V/ ……(2) T∝K・(V/) ² ……(3) Control the frequency and terminal voltage V by the above By doing so, the rotation speed N and torque T are controlled.

In the prior art, it is common to control the relationship between this frequency and the terminal voltage V so that V/≈constant.

On the other hand, the acceleration load characteristics of general rotating equipment can be roughly divided into the following three types.

(1) An acceleration load characteristic in which even if the starting torque is small, the acceleration torque increases as the rotation speed increases. For example, if the blower becomes a load.

(2) When acceleration torque is almost constant from start to steady rotation.

(3) An acceleration load characteristic in which the starting torque is very large and the acceleration torque decreases as the rotation speed increases. For example, the above-mentioned washing machines, centrifugal dehydrators, centrifugal separators, etc.

When this drive method is applied to a washing machine having the accelerated load characteristic described in (3) above, there are two problems.

In other words, first of all, if the conventional method controls V/≒constant, it will not only have over-quality in the high-speed rotation range, but also require a large starting current, which will increase the capacity of the control circuit, resulting in smaller size and lower cost. Price cannot be determined.

Furthermore, in the case of a washing machine, the laundry containing moisture held in the rotating body (drum and basket) tends to shift as the rotation of the rotating body increases, resulting in an unbalanced body and increased vibration of the machine. The size of this unbalance and the degree of occurrence always vary depending on the state of the laundry being lopsided.If the mass of the unbalanced body is large, a large acceleration torque is required and the vibration becomes large. If the rotation speed is increased to steady operation, excessive vibration will cause the equipment to move, creating a dangerous situation.

These two problems are major problems, and there is a need for a small-capacity, low-cost control means that matches the acceleration load characteristics of washing machines, and a safe and reliable acceleration means that can cope with the occurrence of imbalance.

The present invention is directed to a washing machine drive system that deals with a control means that matches the acceleration load characteristics and a safe acceleration means that copes with the occurrence of imbalance, which are problems when applying the above drive system to a washing machine. Its purpose is to provide.

A feature of the present invention is the speed change control of a washing machine using a frequency conversion drive system, which is comprised of a rectifier section that converts alternating current into direct current, and an inverter section that converts the direct current obtained from this rectifier section into alternating current output of an arbitrary frequency. In the speed changing process from starting to steady rotation, the ratio of the frequency applied to the motor and the terminal voltage V, i.e., V/≒constant, is used to change the speed.From the range including starting, to the range where the ratio is changed to change the speed. The switching point _C1 is set in the speed change range of the rotation speed that causes the primary resonance point of the load of the washing machine and the rotation speed that causes the secondary resonance point, and the motor output at the rotation speed that causes this secondary resonance point is set. T _c1 has the relationship between output torque T _s at startup and load torque T _v2 at secondary resonance, that is, T _s > T _c1 > T _v2 (T _v0 : minimum load torque of T _v2 ). The washing machine operating method is set as follows.

In detail, regarding the acceleration load characteristics of a washing machine, the ratio between the frequency applied to the motor and the terminal voltage V, that is, the speed change range including the start where the speed is changed with V/≒ constant, and the speed change range including the start where the speed is changed by changing the ratio and the terminal voltage V Set a speed change range in which the voltage is constant and change the speed, and in the constant terminal voltage speed change range, the set value of the output torque, which decreases in inverse proportion to the square of the frequency, changes depending on the amount of unbalance of the load torque at the time of secondary resonance. It is set within the range of the minimum and maximum values, and when an abnormal imbalance occurs, the drive motor is intentionally stalled and acceleration is stopped, and overcurrent due to the drive motor lock phenomenon is detected and the equipment The system is equipped with an over-imbalance detection function that stops and restarts the operation.

Next, an embodiment of a washing machine driving system according to the present invention will be described with reference to each figure.

First, FIG. 1 is a schematic cross-sectional view of a drum-type washing machine provided in an embodiment of the washing machine drive system of the present invention.
FIG. 2 is a longitudinal sectional view taken along the line XX.

That is, in the illustrated example, a rotating drum is rotated by a drive motor that employs an embodiment of the washing machine drive method of the present invention, which is a frequency conversion drive control method.
This relates to a drum-type washing machine that performs laundry.

Inside the outer frame 1, an outer tank 4 is provided which is elastically suspended from four upper corners of the outer frame 1 by means of hanging rods 3 equipped with vibration-proof springs 2. Outer tank 4
has a horizontal cylindrical shape, and has a horizontal drum bearing part 5 at the center of the rear wall of the outer tank 4, and a drum rotating shaft 6 is rotatably supported on the drum bearing part 5.

Inside the outer tank 4, a cylindrical rotating drum 9, which has a large number of dewatering holes 7 on the peripheral wall and a plurality of protruding lifters 8 at concentric positions, is connected to the drum rotating shaft 6 via a drum flange 10. It is permanently installed. Also,
A drain valve 11 and a motor base 1 are installed at the bottom of the outer tank 4.
2 is fixedly installed, a flexible drain hose 13 is connected to the drain valve 11, and the motor base 12 is
A drive motor 14 for driving the rotating drum 9 is fixedly installed, and friction plates 15 are fixedly installed on both sides of the motor base 12.

Power is transmitted between the rotation shaft of the drive motor 14 and the drum rotation shaft 6 via a motor pulley 16, a belt 17, and a drum pulley 18. Drive motor 1
4, a control unit 19 provided on the upper front surface of the outer frame 1 controls the start, stop, and rotation speed for each process from the washing process to the dehydration process, and the inside of the control unit commands the washing program. It is composed of a sequence control circuit and a frequency conversion drive control circuit for driving the drive motor 14, and 20 is an operation dial of the control unit 19.

On the front surface of the outer frame 1, the front surface of the outer tub 4, and the front surface of the rotating drum 9, a circular outer frame opening, that is, an input port 22 for the laundry 21, is provided at a position concentric with the rotation center of the rotating drum 9. The front surface of the outer tank 4 and the opening of the outer frame 1 are connected by a flexible door bellows 23, and a door 24 is attached to the opening of the outer frame 1 with a hinge so that it can be opened and closed. is door frame 2
5. Consisting of a door glass 26 and a door lock device (not shown), when the door 24 is closed, the lip 27 of the door bellows 23 and the door glass 26 form a watertight structure, preventing the cleaning liquid 28 in the outer tank 4 from leaking. It has a unique structure.

A water faucet (not shown) is installed on the upper back side of the outer frame 1.
Detergent and water are supplied into the outer tank 4 via a water supply hose 30 connected to the outer tank 4 and a detergent dispenser (not shown) for introducing detergent. It is structured so that it can be used.

In addition, there are legs 31 at the four corners of the lower part of the outer frame 1, and on the inside left and right sides of the lower part of the outer frame 1, there are internal mechanical parts, that is, the outer tank 4, which are vibration-proofly supported by the hanging rods 3 during dewatering. A friction damper 32 is fixedly installed to apply a damping effect to the components that serve as the vibrating body using the rotation of the rotating drum 9 as a vibration source, and is structured to slide on the friction plate 15 described above. . Note that the control circuit and the like described later relate to the control unit 19 described above.

To explain the operation of the above structure, when the laundry 21 is loaded into the rotating drum 9, detergent is set in the detergent dispenser (not shown), and the operation dial 20 is set, the water supply valve 29 opens. It is injected into the outer tank 4 together with detergent, and when the set water level is reached, the water supply is automatically stopped and the washing operation starts.

That is, the rotary drum 9 is rotated at a low speed of 50 to 50 rpm by the drive motor 14, and the laundry 21 is repeatedly lifted by the lifter 8 and dropped to the bottom of the rotary drum 9.

The washing operation is carried out by the impact force when it falls and the chemical action of the cleaning liquid 28.

After washing is completed, the drain valve 11 is opened and the cleaning liquid 28 inside the outer tank 4 is discharged to the outside of the machine through the drain hose 13. When rinsing, repeat the same process as when washing (of course, do not add detergent).
Move on to the dehydration process. When dehydrating, after draining,
By switching the speed of the drive motor 14, the rotating drum 9 is rotated at a high speed of 800 to 900 rpm, and water is centrifugally dewatered into the outer tank 4 through the dewatering hole 7 on the peripheral wall of the rotating drum 9, and the drain valve 11 and the drain hose 13 are removed. It is discharged outside the machine through the

In the above configuration, the rotating drum 9
is 50 to 55 rpm when washing and 800 to 900 rpm when dehydrating.
Multiple rotation settings are required, and the high speed range of both is extremely large at 1:16, so the drive motor 14 is
It is controlled and driven by a frequency conversion drive system.

3 and 4 show the relationship between the control method, the load, that is, the required torque of the drum-type washing machine, and the output torque of the drive motor 14. FIG. 4 is a diagram showing the torque curve of the drive motor and the load torque curve with respect to the load rotation speed.

The rotation speed of 50-55 rpm during washing is 800 rpm during spin-drying.
It is included in the shifting range up to 900 rpm, and the 3rd,
Figure 4 shows steady rotation during dehydration (800rpm to 900rpm)
This shows the gear shifting process up to.

As described above, frequency conversion drive control allows the rotation speed and output torque of the drive motor 14 to be controlled by the frequency () and the terminal voltage (V).

In the present invention, the frequency,
By controlling the terminal voltage, V, the drive motor torque curve is calculated for the load required torque curve T _w shown in Fig. 4.
The drive motor 14 is controlled by T _n .

Note that in the following, T _w and T _n are simply abbreviations of the above-mentioned ones, and the same applies to the others.

To give an overview in Figure 3, from the starting speed range _Ns to the maximum rotation speed during dehydration (hereinafter referred to as steady rotation speed).
In the acceleration range up to the steady rotation range N _b (hereinafter referred to as the shift range N _a ), the frequency is linearly increased as in the conventional case.

On the other hand, the terminal voltage V is controlled in a characteristic manner.

In other words, in the shifting range N _a including starting,
V/≒constant, means for increasing the terminal voltage V from the starting terminal voltage _Vs , means for increasing only the frequency by fixing the terminal voltage V at the primary constant voltage _Vc1 , and means for increasing the terminal voltage _Vc1 in a stepwise manner. The frequency is controlled by increasing the frequency by fixing the terminal voltage V at the secondary constant voltage _Vc3 .

Specifically, at the time of starting, the frequency is increased almost linearly from 0 Hz to the set constant rotation switching point C _c , and after the C _c point, the load continues to rotate at a constant speed at a constant frequency.

On the other hand, the terminal voltage V is applied with the starting terminal voltage V _s , and the starting gear shift range N _s is increased at a constant V/≒ constant up to the primary constant voltage setting point C ₁ , and from the C ₁ point to the primary constant voltage switching point C ₂ The voltage changes at the primary constant voltage _Vc1 until the point _C2 , and increases in steps to the secondary constant voltage setting point _C3 .
After point _C3 , the secondary constant voltage V _c3 is used to transition to the steady rotation switching point C _c , and from point C _c onwards, steady rotation is continued at the same V _v3 and V/≈constant.

FIG. 4 shows a comparison between the drive motor torque curve T _n driven by the above control means and the load required torque curve T _w of the drum type washing machine. The above T _n is not the output shaft torque of the drive motor 14, but is the output torque of the drum rotation shaft 6 in consideration of the reduction ratio between the motor pulley 15 and the drum pulley 18, and T _w is also the output torque of the drum rotation shaft 6. is the load torque.

To explain T _w in detail, the maximum torque is required at startup, and the higher the speed, the smaller the acceleration torque. This is because the drainage is installed directly, there is a lot of water contained in the laundry 21, the starting torque is large, and the rotating drum 9
This is because as the rotational speed of the rotating body increases, water is removed by centrifugal force and the weight of the rotating body becomes smaller. Of course, the rotating drum 9 becomes a source of vibration,
In the gear shifting process, there are primary (V ₁ ), secondary (V ₂ ), and tertiary (V ₃ ) resonance points, and the settings and specifications of the vibration isolator consisting of the vibration isolating spring 2 and hanging rod 3 described above, The rotational speed at the time of primary to tertiary resonance at which these resonance points V ₁ to ₃ occur depends on the setting specifications of the damping device composed of the friction plate 15 and the friction damper 32, and further on the setting specifications of the rotating body (rotating drum). N _v1 ,
N _v2 , N _v3 ) and the magnitudes of the primary to tertiary resonance load torques T _v1 , T _v2 , T _v3 are different, but in the case of a drum-type washing machine, the laundry 21 contains a lot of water. The amplitudes at the primary and secondary resonance points V ₁ and V ₂ that occur at relatively low rotational speeds are large, and the load is also large. Furthermore, at least if the secondary resonance point is overcome, the rotation can be accelerated to steady rotation.

Next, to elaborate on the contrast between T _n and T _w above, T _n
is V/≒ from start to primary constant voltage set point C ₁
At start-up, which is constant, that is, constant output torque -
Torque changes at T _s during C ₁ . Of course, the relationship is T _w < T _s , and the _C1 point is set between the rotational speed _Nv1 at the time of primary resonance and the rotational speed _Nv2 at the secondary resonance, and from the _C1 point to the _C2 point, Since the primary constant voltage V _c1 related to the terminal voltage is constant and the frequency increases, the primary constant voltage torque T _c1 related to the motor output decreases in inverse proportion to the square of the frequency. Of course, T _c1 is larger than the load torque T _v2 at the time of secondary _resonance , which is related to the load for surviving the secondary resonance point, and satisfies the relationship T _v2 < T _c1 < T _s , and As shown in Figure 4,
It is set to satisfy the relationship T _vn > T _c1 (=T _vd ) > T _v0 .

T _vn is the maximum load torque at the time of secondary resonance in this drum type washing machine, that is, the load torque when abnormal imbalance occurs, and T _v0 is the minimum load torque of T _v2 at the time of secondary resonance, that is, the generated unbalance. The load torque T _vd when the balance amount is small is T _c1 set by design, and if a load torque greater than T _vd occurs during secondary resonance, the drive motor is set to stall due to insufficient torque. There is.

If T _c1 continues to decrease, the torque at third resonance
At T _v3 or due to stall at high speed, the primary constant voltage V _c1 related to the terminal voltage is increased stepwise to the secondary constant voltage V _c3 up to the C ₃ point at C ₂ points, and the torque is increased to (V _c3 /V _c1 ) Increase in proportion to ² . This is the secondary constant voltage set point. From point C ₃ to point C _c , which is the steady rotation switching point, the secondary constant voltage torque T _c3 related to the motor output decreases to the steady state output torque in the secondary constant voltage section in inverse proportion to the square of the frequency. . Of course, the steady state output torque is larger than the steady state load torque.
In FIG. 4, N _c and N _d indicate the minimum secondary resonance rotation speed and the maximum secondary resonance rotation speed, respectively.

In other words, when an abnormal imbalance occurs,
This purposely stalls the drive motor and does not accelerate the rotating body (rotating drum 9) to high speed rotation except when the set unbalance amount is reached, preventing excessive vibration of the equipment and increasing safety. When a stall occurs, an overload current caused by an overload phenomenon is detected, and an over-imbalance detection mechanism is configured to temporarily stop and restart the equipment.

In FIG. 4, T _c1 ' and T _vd ' are the conventional primary constant voltage torque and secondary resonance design load torque for comparison.

Next, regarding the circuit configuration of the control means, the fifth
This will be explained in the following figures.

The configuration shown in FIG. 5 includes a converter circuit 33 that converts an input AC voltage to a DC voltage, a switching circuit 35 that applies an AC voltage to an electric motor 34 corresponding to the drive motor 14, and the switching circuit 3.
5, an unbalance detection circuit 43 that detects an overload current when the rotational speed of the rotary drum 9 increases in an unbalanced state due to one-sidedness of the laundry 21, and an electric motor 34. It consists of an overcurrent detection circuit 44 that detects a restraint current when the motor is restrained.

The converter circuit 33 includes a rectifier stack 45,
FLS(1)46, FLS(2)47, capacitor C(1)48,
It consists of C(2)49, resistor R(1)50, and R(2)51. FLS(1) 46 is for phase control to control the input AC voltage, and FLS(2) 47 is for voltage doubler rectification. Each operation will be described later.

The imbalance detection circuit 43 will be explained.

The voltage across the resistor R (3) 52 is changed to the variable resistor (1) 53.
The voltage divided by the resistors 54 and 55 is connected to the negative terminal of the comparator (1) 57 via the photocoupler (1) 56, and the voltage corresponding to the set unbalanced current is connected to the positive terminal. resistance 58
and 59 are applied as reference voltages. As for the operation, resistance R(3) 52 is caused by unbalance caused by the laundry 21 being lopsided in the drum 9.
When the potential difference generated across the terminals becomes large and the negative terminal voltage of the comparator (1) 57 transmitted from the photocoupler (1) 56 becomes larger than the reference voltage applied to the positive terminal, as shown in Figures 9 and 10. Signal UNB is issued.

The overcurrent detection circuit 44 also has the same configuration as the unbalance detection circuit 43, and when the potential difference between both ends of the resistor R(3) 52 becomes abnormally large due to the restriction of the motor 34, the comparator (2) 60 to the ninth and eleventh The signal OC shown in the figure is generated.

The processing of the signals UNB and OC within the control signal circuit 42 will be described later.

The control signal circuit 42 has a configuration shown in FIG. 6, and FIG. 7 shows its time chart. The control signal circuit shown in FIG.
6 constitutes a ring counter, and a data selector 67 that switches the phase order for reversing the motor 34 _, and drive signals UP, _UN , _VP , _VN , _WP ,
There are AND circuits 68-73 for obtaining _WN .

These operations are based on the motor rotation speed command V-
Clock pulses CP1 and CP2 are obtained from the F conversion circuit 108 (shown in FIG. 9), and rotation direction commands are obtained.
Dir is obtained by another command. The clock pulse CP1 triggers the ring counter FF6.
1 to 63, the time chart 6 shown in FIG.
1Q, 61 to 63Q, 63 are obtained. In addition, the clock pulse CP2 causes the ring counters FF64 to 66 to display the time charts 64Q, 64 to 66Q, and 66 shown in FIG.
Q is obtained. Using AND circuits 68 to 73, each of the outputs of the above FFs is converted into drive signals _UP , _UN ,
V _P , V _N , W _P , and W _N are obtained as shown in the time chart shown in FIG.

The circuit shown in FIG. 8 is a voltage control circuit, and is a drive circuit for the FLS(1) 46 and FLS(2) 47 described above.

The operation will be explained below.

First, a method of controlling the input AC voltage will be explained.

The input signal B is an inverted waveform (shown in FIG. 8) after full-wave rectification of the input AC voltage, and is synchronized with the frequency of the input AC voltage. Input signal B is
It is biased by a resistor 76 and a capacitor 77 via a resistor 75, and is input to the base of a transistor 78 (hereinafter, signal waveforms of each part of the circuit are shown in FIG. 8).

The collector of the transistor 78 is connected to the base of the transistor 80 via the resistor 79, and the collector of the transistor 80 is connected to the negative voltage (-VEE) via the resistor 81.
The signal obtained from the collector of transistor 80 becomes a triangular wave shown in FIG. 8, and is input to the negative terminal of comparator 82. A positive terminal of the comparator 82 is connected through a resistor 83.
The output signal of the operational amplifier 84 is input. The positive terminal of the operational amplifier 84 has V-F as shown in FIG.
The input signal V1 of the converter 109 is inputted through the resistor 85, amplified by an amplification factor determined by the ratio of the resistors 86 and 87, and outputted from the output terminal of the operational amplifier 84.

As shown in FIG. 8, the comparator 82
The output signal of is a square wave, and the diode 88,
It is input to the base of transistor 90 via resistor 89. At the emitter of the transistor 90,
A pulse transformer 91 is connected, and its secondary terminals G1, K1 are connected to FLS(1) 46 shown in FIG.

Therefore, the input signal V of the V-F converter 109
1 is amplified by the operational amplifier 84, that is, the signal input to the positive terminal of the comparator 82, and compared with the triangular wave signal obtained from the collector of the transistor 80, FLS(1)4 is obtained.
By changing the conduction angle of 6, the input AC voltage is controlled.

Next, the voltage doubler rectification control circuit will be explained.

The positive terminal of the comparator 92 receives the input signal V1 of the V-F converter 109 shown in FIG.
When the input signal V1 becomes larger than the reference signal, the comparator 92
The output of is inverted and becomes LOW as shown in Figure 8.
state to HIGH state. Comparator 9
The output of 2 is input to the input terminal J of FF96,
A HIGH signal is sent from the output terminal Q of the FF 96 to the oscillation circuit 97 in the next stage in synchronization with the rise of a clock pulse, which will be described later, that is input to the input terminal CK of the FF 96. The oscillation circuit 97 includes NAND circuits 98 and 99
, resistors 100 and 101, and a capacitor 102, and one input terminal of the NAND circuit 98 is connected to the
It oscillates in synchronization with the input of a HIGH signal from the output terminal Q of the FF96, and the output is sent to the transistor 10 via the diode 103 and the resistor 104.
It is input to the base of 5. The transistor 105 is repeatedly turned ON and OFF by the signal input to the base of the transistor 105 (the oscillation signal shown in FIG. 8), and a voltage is generated between the secondary side terminals G2 and K2 of the pulse transformer 106 connected to the emitter. A signal having the waveform shown in FIG. 8 is generated. Since the secondary terminals G2 and K2 of the pulse transformer 106 are connected to the FLS(2) 47 shown in FIG. The converter circuit 33 shown in FIG. 5 becomes a voltage doubler rectifier circuit. The clock pulse input to the input terminal CK of the FF 96 is obtained from the collector of the transistor 78 via the NOT circuit 107 as shown in FIG. It is also synchronized with the timing at which the input AC voltage crosses zero.

The clock pulse obtained in this way is
The operation of the oscillation circuit 97 is completely synchronized with the zero-crossing timing of the input AC voltage. Therefore, the input signal V1 of the V-F converter 109 shown in FIG. to J
A clock pulse synchronized with the zero-crossing timing of the input AC voltage is input to the input terminal CK of the FF96, and FLS(2) is input in synchronization with the rising edge of the clock pulse.
47 will be controlled ON-OFF.

The circuit shown in FIG. 9 rotates the motor 34 using the V-F conversion circuit 108 which is the motor rotation speed command, the signal UNB from the unbalance detection circuit 43 mentioned above, and the signal OC from the overcurrent detection circuit 44. This is a stop timer circuit that stops the motor for a certain period of time.

First, the V-F conversion circuit 108 will be explained.

A resistor 11 is connected to the input terminal of the V-F converter 109.
0, capacitor 111 is connected in parallel with GND,
Further, a capacitor 112 and a resistor 113 constitute an integrating circuit, to which an input voltage V1 corresponding to the required number of rotations of the rotary drum 9 is applied. transistor 1
A stop signal STOP, which will be described later, is input to the base of the motor 34 through a resistor 115, and when this signal is input, the transistor 114 is turned on and the input voltage V1 is lowered to the GND potential. This prevents the engine from being driven at a high frequency when restarting. The output terminal of the V-F converter 109 is pulled up by a resistor 116, and CP1 is sent through a NOT circuit 117, and CP2 is sent from the input side of the NOT circuit 117 to the control signal circuit 42 described above.

Next, the stop time limit circuit will be explained.

The input potential of the V-F converter 109 is applied to the positive terminal of the comparator 118 and the negative terminal of the comparator 119, and the negative terminal of the comparator 118 has a potential corresponding to the rotation speed at point _Nd shown in FIG. , is applied as reference potential B by resistor 120 and resistor 121, and comparator 1
The negative terminal of 19 has a potential corresponding to the rotational speed of point _Nc shown in Fig. 4, which is connected to resistors 122 and 123.
is applied as a reference potential A. The outputs C and D of comparators 118 and 119 and the signal UNB from the aforementioned unbalance detection circuit 43 are
is input to the NAND circuit 124, and the output E and
The signal OC from the overcurrent detection circuit described above is connected to the load terminal L of the counter 125 and the reset terminal R of the FF 126. An oscillator 128 is connected to a clock terminal CK of the counter 125 via a NAND circuit 127. The ripple carry terminal RC of the counter 125 is connected to the clock terminal CK of the FF 126 via a NOT circuit 129.
The signal G from the output terminal is connected to the resistor 1
30 and a capacitor 131 to one input terminal of the NAND circuit 132,
The signal G is connected to the other input terminal of NOT circuit 1.
33, and two NOT circuits 134,
The circuit configuration is such that a Reset signal and a STOP signal are transmitted via 135.

The operation of the circuit shown in FIG. 9 will be explained with reference to the time chart shown in FIG. 10.

Comparators 118 and 119 constitute a window comparator, and when the input voltage V1 reaches within the range of each reference potential A, B, that is, the secondary resonance rotation speed range (N _c ~ _Nd )
When the rotational speed of the rotating drum 9 reaches , and the unbalance signal UNB is transmitted, the NAND
The output signal E of the circuit 124 has the same width as the signal UNB, and is a pulse signal of HIGH→LOW→HIGH. The signal E is the load terminal L of the counter 125.
When input to the reset terminal R of the FF126, the output signal G of the FF126 is inverted from LOW to HIGH, and the output of the oscillator 128 is input to the NAND circuit 12.
7 to the counter 12 as a clock signal F.
It is input to the clock terminal CK of No.5. At the same time, the signal G is connected to the resistor 130 and the capacitor 1.
Integrating circuit and NOT circuit 13 consisting of 31
3, and the stop signal STOP is transmitted from the output of the NOT circuit 135 to the diode OR circuit shown in FIG.

Furthermore, after the counter 125 starts operating and a period of time has elapsed according to the setting conditions of the input terminals A, B, C, and D, a signal H is transmitted to the clock terminal CK of the FF 126 via the NOT circuit 129. FF126
The output signal G of is inverted from HIGH to LOW, keeping the signal F as HIGH and the stop signal
STOP is inverted from HIGH to LOW, and the reset signal Reset is sent to the NAND circuit 1 through an integrating circuit composed of a resistor 130 and a capacitor 131.
32 and the NOT circuit 134, the signal is input to the diode OR circuit shown in FIG. Also,
Signal OC from overcurrent detection circuit 44 is NOT circuit 1
36 to the load terminal L of the counter 125 and the reset terminal R of the FF 126, the signals E, F, G, H, shown in FIG.
It is the same as the time chart for STOP and Reset.
Next, the processing of the signals OC, STOP, and Reset in the control signal circuit will be explained with reference to FIGS. 6, 9, 10, and 11.

As shown in Fig. 11, when signal E (LOW) is generated, a stop signal is sent to the set terminal S of FF74.
STOP (HIGH) is input, and the output Q of FF74 is
It becomes HIGH and is input to the set terminal S of FF64-66. Then, the output Q of each of the FFs 64 to 66 is held in a HIGH state, and the output is held in a LOW state. Furthermore, the output Q of the FF74 is also input to the enable terminal E of the data selector 67, and all output terminals Y ₁ to Y ₄ of the data selector 67 are also input to the enable terminal E of the data selector 67.
Since it is held in the LOW state, AND circuits 68 to 7
3 outputs U _P , U _N , V _P , V _N , W _P , W _N are all
It will be held in the LOW state. Next, the ninth
After a certain period of time, the counter 125 shown in the figure inverts the stop signal STOP (HIGH→
LOW) and at the same time, the reset signal Reset
(HIGH) occurs, and the above-mentioned AND circuits 68 to 73
Release the outputs U _P ~ W _N from the LOW state. 1st
Figure 1 shows the time chart. Also, when the signal OC from the overcurrent detection circuit occurs, the sixth
The processing in the control signal circuit shown in the figure is completely the same as described above.

According to the embodiments of the present invention described above, the following effects can be expected.

As the rotation of the rotating drum increases, moisture-containing laundry becomes uneven, creating an unbalanced load and increasing the vibration of the washing machine.In this state, if the drum rotation speed is increased to the dehydrating steady rotation speed, the washing machine will stop washing. As mentioned in the prior art section, the vibration of the machine becomes abnormally large, leading to a dangerous situation. However, according to the present invention, the vibration of the drum becomes the largest, and second only during startup, during acceleration. By reducing the motor torque in proportion to the square of the frequency at a rotation speed lower than the secondary resonance point where torque is required, it is possible to set the amount of unbalance at the secondary resonance point, and furthermore, it is possible to set the amount of unbalance at the secondary resonance point. If the amount of unbalance is reached, the motor is stalled, stopped for a certain period of time, and then started again to increase the rotation of the drum, and this process is repeated until the amount of unbalance is smaller than the above setting. By returning the washing machine, abnormal vibrations of the washing machine can be reliably prevented.

In summary, the present invention provides a washing machine drive system that includes a control means that matches the acceleration load characteristics of the washing machine and a safe acceleration means that can cope with the occurrence of imbalance. This invention can be said to have excellent effects.

[Brief explanation of the drawing]

FIG. 1 is a schematic cross-sectional view of a drum-type washing machine used in an embodiment of the washing machine drive system of the present invention, and FIG. 2 is a longitudinal cross-sectional view taken along the line X-X of FIG. Third
The figure is a conversion curve of frequency and terminal voltage with respect to load rotation speed, Figure 4 is a diagram of the drive motor torque curve and load torque curve with respect to load rotation speed, and Figure 5 is a diagram of the drive motor torque curve and load torque curve with respect to load rotation speed
The figure is a control means circuit configuration diagram according to an embodiment, No. 6
The figure shows the control signal circuit diagram, FIG. 7 shows the time chart, and FIG. 8 shows the voltage control circuit diagram.
Figure 9 is a diagram of the V-F conversion circuit and stop timer circuit, Figure 10 is a time chart of the circuit in Figure 9, and Figure 11 is a time chart when the stop timer circuit is in operation. be. 1...Drum rotating shaft, 9...Rotating drum, 14
...Drive motor, 16...Motor pulley, 18...
...Drum pulley, 19...Control unit, 33...
... converter circuit, 34 ... electric motor, 35 ... switching circuit, 42 ... control signal circuit, 43 ...
...Unbalance detection circuit, 44 ... Overcurrent detection circuit, 45 ... Rectifier stack, 46 ... FLS (1), 4
7...FLS(2), 108...V-F conversion circuit, 10
9... V-F converter, CP1, CP2... Clock pulse, A... Frequency conversion curve, B... Terminal voltage conversion curve, N _s ... Starting gear shift range, N _a ... Gear shifting range, N _b ... Steady rotation range, C ₁ ...Primary constant voltage setting point, C ₂ ...Secondary constant voltage setting point, C ₃ ...Tertiary constant voltage setting point, V _s ...Starting terminal voltage, V _c1 ...Primary constant voltage , V _c3 ... Secondary constant voltage, C _c ... Steady rotation switching point, V ₁ ... Primary resonance point, V ₂ ... Secondary resonance point,
V ₃ ……Third resonance point, N _v1 ……Rotation speed at primary resonance,
N _v2 ...Rotation speed at secondary resonance, N _v3 ...Rotation speed at tertiary resonance, T _n ...Drive motor torque curve, T _w ...
Required torque curve for drum type washing machine, T _c1 ...Primary constant voltage torque related to motor output, T _s ...Starting -C ₁
T _v1 , T _v2 , T _v3 ... Load torque at primary, secondary, and tertiary resonance, T _vd ... Set load torque at secondary resonance, T _vn , T _v0 ... Maximum, minimum at secondary resonance Load torque, N _c , N _d ...Secondary resonance minimum and maximum rotation speed.

Claims (1)

[Scope of Claims] 1. Speed change control of a washing machine using a frequency conversion drive system, which is comprised of a rectifier section that converts alternating current into direct current, and an inverter section that converts the direct current obtained by the rectifier section into alternating current output of an arbitrary frequency. , the ratio of the frequency applied to the motor during the speed change process from startup to steady rotation and the terminal voltage V, that is, V/
≒ Switching point from a shifting range that includes the start where the gears are shifted at a constant rate to a range where the gears are shifted by changing the ratio.
Set C ₁ in the range of the rotation speed that causes the primary resonance point of the load of the washing machine and the rotation speed that causes the secondary resonance point, and calculate T _c1 related to the motor output at the rotation speed that causes this secondary resonance point. is between the output torque T _s at the time of starting and the load torque T _v2 at the time of secondary resonance, that is, T _s >
A washing machine drive system characterized by setting the relationship such that T _c1 > T _v0 (T _v0 : minimum load torque of T _v2 ). 2. In what is stated in claim 1,
The design load torque T _vd is set within the range of the maximum (T _vn ) and minimum (T _v0 ) of the load torque during secondary resonance caused by the difference in the amount of unbalance, and T _c1 related to the motor output and the above T _vd are set. are set equal and T _vn > (T _c1 =
A washing machine drive system that is set so that the relationship T _vd ) > T _v0 . 3 In what is stated in claim 2,
When a secondary resonance load (over-unbalanced load) with a value larger than T _c1 (= T _vd ) occurs, an over-unbalance detection device detects the overload current caused by motor stall (overload phenomenon). A washing machine drive system that detects this and stops the washing machine, or stops and restarts it. 4 In what is stated in claim 3,
A washing machine drive system in which the operating range of the over-imbalance detection device is between the minimum and maximum rotation speeds at which secondary resonance occurs.