JP3446692B2 - Control device for single-phase motor, actuator and blower using control device for single-phase motor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for a single-phase motor used in, for example, an air conditioner or a fan of a ventilation fan.

[0002]

2. Description of the Related Art FIG.
FIG. 33 shows a conventional AC voltage control device described in Japanese Patent No. 4 publication, in FIG. 32, 1 is an AC power supply, 2 is a load, 3
Is a switching circuit, 4 is a flywheel circuit, 9 and 1
0 is a switching transistor, 11 and 12 are flywheel transistors, and 13 to 16 are diodes.

Next, the operation will be described. In both the positive and negative directions of the AC power supply 1, the switching transistors 9 and 10 are switched at a frequency higher than the power supply frequency to control the average value of the AC voltage applied to the load 2.
Even when the switching transistors 9 and 10 are off, by turning on the flywheel transistors 11 and 12, respectively, the current of the load 2, which is an inductive load, can be kept flowing. For example, the switching transistor 10 is switched in the positive half cycle of the AC power supply 1. When the switching transistor 10 is off, by turning on the flywheel transistor 12, it is possible to keep the current flowing through the load 2. The diodes 13 to 16 are connected to the respective transistors so that a reverse voltage is not applied.

In this way, the current path of the load 2 is generated by the flywheel transistors 11 and 12 even when the switching transistors 9 and 10 are off in both positive and negative directions, so that the current is continuous without interruption. Then, the AC voltage can be controlled.

[0005]

Since the conventional AC voltage control device is constructed as described above, the emitter sides of the respective transistors are not connected to each other. Therefore, one driving power source is provided for each transistor. However, there is a problem in that a total of four driving power supplies are required, the power supply circuit for generating the driving power supplies becomes large, and the cost increases.

The present invention has been made to solve the above problems, and an object thereof is to obtain a control device for a single-phase motor that is low in cost and high in reliability.

[0007]

A control device for a single-phase motor according to the present invention is a switching device connected between an AC power supply and a single-phase motor so as to perform switching in both positive and negative directions at a frequency higher than a power supply frequency. Circuit, a flywheel circuit connected between terminals of the single-phase motor so as to perform flywheeling in both positive and negative directions, and a pulse signal that is input to the main switching element of the switching circuit is generated to control the switching circuit. An oscillation circuit, and a flywheel switching circuit that controls a switching element of the flywheel circuit based on the AC power supply voltage ,
Current direction detection to detect the direction of current flowing in a single-phase motor
Means for detecting the current detected by the current direction detecting means.
The polarity of the current flowing through the single-phase motor and the voltage of the AC power supply is reversed
Switching circuit stops switching during the period
However, the oscillation circuit is controlled so as to be fully energized .

Further, a switching circuit connected between the AC power supply and the single-phase motor so as to perform switching in both positive and negative directions at a frequency higher than the power supply frequency, and the single phase so as to perform flywheeling in both positive and negative directions. A flywheel circuit connected between the terminals of the motor, a zero-cross detection circuit that detects the voltage of the AC power supply, and a pulse signal that is input to the main switching element of the switching circuit to generate and generate, and an oscillation that controls the switching circuit. comprising a circuit, and a flywheel switching circuit for controlling the switching elements of the flywheel circuit by a voltage detected by the zero-cross detection circuit, the zero crossing detector
Zero cross timing and flywheel switching times
It is designed so that there is a time lag with the switching timing of the road .

Further, the switching circuit is composed of a switching transistor and a diode bridge.

Further, the switching circuit is directly driven by the oscillation circuit.

Further, a current direction detecting means for detecting the direction of the current flowing through the single-phase motor is provided, and in a period in which the polarity of the current flowing through the single-phase motor detected by the current direction detecting means and the voltage of the AC power source is reversed. , The switching of the switching circuit is stopped, and the oscillation circuit is controlled so as to be fully energized.

Further, a surge absorbing element for absorbing a surge of the single-phase motor is provided between the terminals of the single-phase motor.

Further, the actuator according to the present invention is
The controller for a single-phase motor according to any one of the above is used.

Further, a blower according to the present invention uses the single-phase motor controller described in any of the above.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. Embodiment 1 of the present invention will be described below with reference to the drawings. Figure 1
FIG. 1 is a block diagram of a control device for a single-phase motor according to Embodiment 1 of the present invention. In the figure, 1 is an AC power supply, 2 is a single-phase induction motor, 3 is a switching circuit, 9 and 10 are switching transistors, 4 is a flywheel circuit, 11 and 12 are flywheel transistors, and 1
3 to 16 are diodes, 5 is a zero-cross detection circuit that detects the voltage of the AC power supply 1, 6 is an oscillation circuit that generates a pulse signal that is input to the switching circuit 3, and 7 is a switching transistor that uses the voltage detected by the zero-cross detection circuit 5. A switching switching circuit for switching between 9 and 10;
Is a control circuit composed of a flywheel switching circuit for switching the flywheel transistors 11 and 12 according to the state of the switching circuit 3. The switching circuit 3 connects the emitter sides of the switching transistors 9 and 10 to each other, and connects the diodes 13 and 1 in parallel.
4 is connected. The flywheel circuit 4 has the same circuit configuration as the switching circuit 3.

Next, the operation of the first embodiment will be described. FIG. 2 is an operation timing chart of the control device for a single-phase motor according to the first embodiment of the present invention. The voltage waveform of the AC power supply 1 and the current waveform of the single-phase induction motor 2, the pulse signal waveform of the oscillation circuit 6, and the switching transistor. Drive waveforms 9 and 10, flywheel transistors 11 and 12
3 shows the operation timings of the drive waveform and the voltage waveform applied to the single-phase induction motor 2.

In FIGS. 1 and 2, the oscillator circuit 6 constantly generates a pulse signal to be input to the switching circuit 3. During the positive half cycle T1 of the AC power supply 1, the switching switching circuit 7 causes the switching transistor 10 to operate.
The pulse signal generated by the oscillation circuit 6 is input to the switching circuit to perform switching, and the driving voltage is input to the switching transistor 9 to be constantly turned on. Further, during T1, the flywheel switching circuit 8 turns on the flywheel transistor 12. Here, the single-phase induction motor 2 is connected between T1a, where the voltage and current of the AC power supply 1 are in phase
Current flows in the direction (A).

When the switching transistor 10 is on, a current flows in the path of the AC power supply 1 → single-phase induction motor 2 → switching transistor 10 → diode 13 → AC power supply 1. Even if the switching is turned off, the single-phase induction motor 2 is an inductive load, and therefore tries to keep the current flowing. When the switching transistor 10 is turned off, the current continues to flow in the direction of (A) in the path of the single-phase induction motor 2, the flywheel transistor 12, the diode 15 and the single-phase induction motor 2.

Further, between T1b where the phases of the voltage and the current of the AC power supply 1 are reversed, a current flows in the direction (B) in the single-phase induction motor 2. During this period, since the switching transistor 9 is always turned on, a current flows through the path of AC power supply 1 → switching transistor 9 → diode 14 → single-phase induction motor 2 → AC power supply 1. The switching transistor 9 is always turned on without being switched. When the switching is performed between T1b, the flywheel circuit 4 operates normally because the flywheel transistor 11 is turned off when the switching is turned off. However, since the current path of the single-phase induction motor 2 is cut off and a surge voltage is generated, switching stops during this period. Between T1b, since the voltage of the AC power supply 1 is applied to the single-phase induction motor 2 as it is, the current path is not interrupted and the occurrence of the surge between the terminals of the single-phase induction motor 2 is prevented.

The switching switching circuit 7 switches the switching transistors 9 and 10 according to the voltage detected by the zero-cross detection circuit 5, and the switching transistor 9 switches the power supply voltage. Further, the flywheel switching circuit 8 switches the flywheel transistors 11 and 12, and performs the same operation as described above during the negative half cycle T2.

The switching operation here will be described. Figure 3
FIG. 3 is an operation timing chart of the control device for a single-phase motor according to the first embodiment of the present invention, showing a voltage waveform in the vicinity of the zero cross of the voltage detected by the zero cross detection circuit, a driving waveform of the switching transistors 9 and 10, a flywheel transistor 11 The operation timings of the drive waveforms 12 and 12 are shown.

The flywheel circuit 4 switches the flywheel transistors 11 and 12 at the voltage zero-cross timing detected by the zero-cross detection circuit 5, and the switching circuit 3 detects the detected voltage higher than zero.
For example, by performing switching and switching between full energization at the timing of the detected voltage value = ± 10 V, a time difference of about 200 μsec is provided for the switching timing of the switching circuit 3 and the flywheel circuit 4. That is, a time difference of 200 μscc occurs after the switching operation is completed and the flywheel is switched. The surge between the terminals of the single-phase induction motor 2 occurs when the current path is cut off. Since the switching is performed with a time difference of 200 μsec here, the current path is always generated and the surge is not generated. It can be surely prevented.

The on / off ratio of the pulse signal generated in the oscillating circuit 6 (hereinafter referred to as "on duty") is changed to control the average value of the AC voltage applied to the single-phase induction motor 2.

In this case, since the transistors used in the switching circuit 3 and the flywheel circuit 4 can be driven by the same power source, respectively, the transistors can be driven by a total of two power sources, the circuit is simplified, and the cost is reduced. it can.
Further, since there is a time difference between the switching timings of the switching circuit 3 and the flywheel circuit 4, even if an error occurs in the switching timing, surge is prevented from occurring and the circuit is prevented from being destroyed, and a highly reliable single-phase motor is provided. The control device of is obtained.

Embodiment 2. The second embodiment of the present invention will be described below with reference to the drawings.
4 is a block diagram of a controller for a single-phase motor according to Embodiment 2 of the present invention. The switching transistors 9 and 10 and the flywheel transistor 1 shown in FIG.
1 and 12, and the switching circuit 3 and the flywheel circuit 4 in which the diodes 13 to 16 are connected in the reverse direction.

The basic control operation here is the first embodiment.
Is the same as In this case, since the switching circuit 3 and the flywheel circuit 4 are connected to the collector side of the transistor, the same heat radiation fin is formed by using a non-insulated element whose collector side is not insulated, such as TO220. Even when used, it is not necessary to insulate the elements from each other, an insulating sheet is not required, and cost reduction can be realized.

Embodiment 3. The third embodiment of the present invention will be described below with reference to the drawings.
5 is a block diagram of a control device for a single-phase motor according to a third embodiment of the present invention. The flywheel circuit 4 shown in FIG.
In this configuration, a transistor and a diode are connected to, and those connected in parallel are used.

The basic control operation here is the first embodiment.
Is the same as In this case, since the switching transistors 9 and 10 of the switching circuit 3 can be driven by the same power source, the circuit can be simplified, and the size and cost can be reduced.

Fourth Embodiment Embodiment 4 of the present invention will be described below with reference to the drawings.
6 is a block diagram of a control device for a single-phase motor according to Embodiment 4 of the present invention. In FIG. 6, 1 is an AC power supply, 2 is a single-phase induction motor, 3 is a switching circuit, and 9 and 10 are for switching. Transistors, 4 is a flywheel circuit, 11 and 12 are flywheel transistors, 13 to 16 are diodes, 5 is a zero cross detection circuit for detecting the voltage of the AC power supply 1, and 6 is a switching circuit 3.
An oscillation circuit for generating a pulse signal to be input to the control circuit 8 is a control circuit composed of a flywheel switching circuit for switching the flywheel transistors 11 and 12 according to the voltage detected by the zero-cross detection circuit 5.

The control operation of the flywheel switching circuit 8 here is the same as that of the first embodiment.

FIG. 7 is an operation timing chart of the control apparatus for a single-phase motor according to the fourth embodiment of the present invention. The voltage waveform of the AC power supply 1 and the switching transistors 9 and 10 are shown.
The operation timings of the pulse signal waveform of the oscillation circuit 6, the drive waveforms of the flywheel transistors 11 and 12, and the voltage waveform applied to the single-phase induction motor 2, which are the drive waveforms of FIG.

When controlling a motor in which the phase difference between the voltage of the AC power supply 1 and the current of the single-phase induction motor 2 is small, the amount of surge generation is small and the switching transistors 9 and 10 are small.
Since the switching circuit 7 shown in FIG. 1 is unnecessary, the switching circuit 3 can be directly driven by the oscillation circuit 6. Therefore, the control circuit can be simplified, and the circuit can be downsized and the cost can be reduced.

FIG. 8 shows another circuit configuration in this embodiment. Since it is not necessary to switch the switching circuit 3, the same control operation can be performed with the configuration using the switching transistor 17 and the diode bridge 18 in the switching circuit 3.

Embodiment 5. Embodiment 5 of the present invention will be described below with reference to the drawings.
FIG. 9 is a block diagram of a control device for a single-phase motor according to a fifth embodiment of the present invention. Current direction detection means 19 for detecting the direction of the current flowing through the single-phase induction motor 2 is added to the control device shown in FIG. It was done.

Next, the operation of this embodiment will be described. The basic control operation here is the same as that of the fourth embodiment. FIG. 10 shows the voltage waveform of the AC power supply 1, the current waveform of the single-phase induction motor 2, the switching transistors 9 and 1.
The operation timings of the drive waveform of 0 and the drive waveforms of the flywheel transistors 11 and 12 are shown. The direction of the current flowing through the single-phase induction motor 2 is detected by the current direction detecting means 19, and the switching of the switching circuit 3 is stopped during the period in which the polarity of the current and the voltage of the AC power supply 1 is reversed, and the oscillation is performed so as to be fully energized. The circuit 6 is controlled.

If switching is performed in the period in which the polarities of the voltage and the current are reversed, the flywheel circuit 4 does not operate normally when the switching circuit 3 is turned off, so that the current path of the single-phase induction motor 2 is cut off. , A surge may occur between the terminals of the single-phase induction motor 2 and the circuit may be destroyed. With this method, the surge is reliably prevented,
It is possible to obtain a highly reliable single-phase motor control device.

Sixth Embodiment Embodiment 6 of the present invention will be described below with reference to the drawings.
11 is a block diagram of a control device for a single-phase motor according to a sixth embodiment of the present invention, in which a surge absorbing element 20 is added between terminals of a single-phase induction motor 2 of the control device shown in FIG. The basic control operation here is the fourth embodiment.
Is the same as

In this case, switching is performed in the period in which the polarities of the voltage and the current are reversed, and even when a surge occurs between the terminals of the single-phase induction motor 2, the surge absorbing element 20 absorbs the surge to thereby make the circuit. It is possible to prevent destruction and obtain a highly reliable single-phase motor control device.

Embodiment 7. Embodiment 7 of the present invention will be described below with reference to the drawings.
The circuit configuration is shown for the same case as in the first to third embodiments, and the basic control operation is as described above.
Next, the operation of this embodiment will be described. FIG. 12 is an operation timing chart of the control device for a single-phase motor according to the seventh embodiment of the present invention. The detected voltage waveform of the voltage detected by the zero-cross detection circuit 5 near the zero cross, the drive waveform of the switching transistor 9, the flywheel. The operation timing of the drive waveform of the transistor for use 11 is shown.

In FIG. 12, in the vicinity of the zero cross where the voltage detected by the zero cross detection circuit 5 changes from negative to positive, the input of the pulse signal to the switching transistor 9 is finished before Td1 before the detected voltage is zero, and the driving is performed. Full energization by inputting voltage. In addition, before the detection voltage is zero, the flywheel transistor 1 is placed before Td2.
Turn off 1. The relationship between Td1 and Td2 at this time is shown in Expression (1). Td1>Td2> 0 (1)

Here, an example of a method of generating Td1 and Td2 will be described. The power supply voltage of the AC power supply 1 is AC10
When the detection voltage value in the zero-cross detection circuit 5 is 8.88 V in the case where the power supply frequency is 0 V and the power supply frequency is 50 Hz, 200 μs is calculated from the formula (2) with respect to the detection voltage zero.
There is a time difference of ec, and by controlling the switching switching circuit 7 with the detection voltage value = 8.88 V, a time difference of 200 μsec can be provided with respect to zero detection voltage.

[0042]

[Equation 1]

Similarly, the flywheel switching circuit 11
Is T by switching at the detected voltage value = 4.44V.
A time difference of d2 = 100 μsec can be provided.
Here, the time difference can be arbitrarily set by changing the detection voltage that generates the switching timing.

For example, Td1 = 200 μsec, Td2
= 100 μsec, the switching transistor 9 stops switching 200 μsec before the zero voltage detected by the zero-crossing detection circuit 5 and full energization occurs, and the flywheel transistor 11 outputs 100 μsec.
Turn off before μsec. In this case, even if the detected voltage zero is delayed with respect to the voltage zero cross of the AC power supply 1, since the detection error of the zero cross detection circuit 5 has a detection margin of 100 μsec, malfunction of the flywheel circuit 4 can be prevented. Further, the switching timing of the switching circuit 3 and the flywheel circuit 4 is 200-100 = 10.
There is a time difference of 0 μsec, and there is a margin in the switching error of the switching timing.

FIG. 13 is an operation timing chart of the control device for a single-phase motor according to the seventh embodiment of the present invention. In the figure, in the vicinity of the voltage zero cross that changes from positive to negative, the voltage zero detected by the zero cross detection circuit 5 is shown. Than Td
One pulse before, the input of the pulse signal to the switching transistor 10 is completed, and the drive voltage is input to make full conduction. Further, the flywheel transistor 12 is turned off before Td2 before the detected voltage zero.

In this case, even if the voltage zero-cross detected by the zero-cross detection circuit 5 is slightly delayed with respect to the voltage zero-cross of the AC power supply 1 and a deviation occurs, a detection margin between Td2 is provided so that the zero-cross detection circuit 5 detects the voltage zero-cross. In the circuit configuration in which the voltage zero crossing is delayed, it is possible to prevent a power supply short circuit due to a malfunction of the flywheel circuit 4. Further, since the switching circuit 3 and the flywheel circuit 4 have a margin for switching between Td1 and Td2, it is possible to prevent the occurrence of a surge even if an error occurs in the switching timing. With this method, a highly reliable single-phase motor control device can be obtained.

Embodiment 8. Embodiment 8 of the present invention will be described below with reference to the drawings.
The circuit configuration is shown for the same case as in the first to third embodiments, and the basic control operation is as described above.

Next, the operation of this embodiment will be described. FIG. 14 is an operation timing chart of the control device for a single-phase motor according to Embodiment 8 of the present invention. The detected voltage waveform in the vicinity of the zero cross of the voltage detected by the zero cross detection circuit 5, the drive waveform of the switching transistor 9, and the flywheel. The operation timing of the drive waveform of the transistor for use 11 is shown.

In FIG. 14, in the vicinity of the zero cross where the voltage detected by the zero cross detection circuit 5 changes from positive to negative, the flywheel transistor 1 after Td4 from the voltage zero cross detected by the zero cross detection circuit 5.
1 is turned on, and the input of the pulse signal to the switching transistor 9 is started after Td3 from the voltage zero cross. The relationship between Td3 and Td4 at this time is shown in Expression (3). Td3>Td4> 0 (3)

Generation of Td3 and Td4 can be performed by the same method as in the seventh embodiment. For example, Td3 = 200
When μsec and Td4 = 100 μsec are set, the switching transistor 9 starts switching from full energization after 200 μsec with respect to the voltage zero detected by the zero-cross detection circuit 5, and the flywheel transistor 11 is turned on after 100 μsec. In this case, since the detection error of the zero-cross detection circuit 5 has a detection margin of 100 μsec, it is possible to prevent the flywheel circuit 4 from malfunctioning. In addition, the switching timing of the switching circuit 3 and the flywheel circuit 4 is 200-100 =
There is a time difference of 100 μsec, and there is a margin in the switching error of the switching timing.

FIG. 15 is an operation timing chart of the control apparatus for a single-phase motor according to Embodiment 8 of the present invention. In the figure, in the vicinity of the voltage zero cross that changes from positive to negative, the voltage zero detected by the zero cross detection circuit 5 is shown. Than Td
After 4 hours, the flywheel transistor 11 is turned on, and the switching transistor 9 is started to input the pulse signal after Td3 after the voltage zero cross.

In this case, even if the voltage zero-cross detected by the zero-cross detection circuit 5 advances slightly with respect to the voltage zero-cross of the AC power source 1 and a deviation occurs, there is a detection margin for the time Td4, so the zero-cross detection circuit. In the circuit configuration in which the voltage zero crossing detected in 5 advances,
A power supply short circuit due to a malfunction of the flywheel circuit 4 is prevented. Furthermore, switching circuit 3 and flywheel circuit 4
Since there is a margin for switching Td3 to Td4, it is possible to prevent the occurrence of a surge even if an error occurs in the switching timing. With this method, a highly reliable single-phase motor control device can be obtained.

Ninth Embodiment Embodiment 9 of the present invention will be described below with reference to the drawings.
The circuit configuration is shown for the same case as in the first to third embodiments, and the control operation is for performing the operations of the seventh and eighth embodiments at the same time.

Next, the operation of this embodiment will be described. 16 and 17 are operation timing charts of the controller for a single-phase motor according to Embodiment 9 of the present invention. The detected voltage waveform of the voltage detected by the zero-cross detection circuit 5 near the zero-cross, the switching transistors 9 and 10. The operation timings of the drive waveforms and the drive waveforms of the flywheel transistors 11 and 12 are shown. Td
The method of generating 1 to Td4 is the same as in the seventh embodiment.

In this case, before and after the voltage zero cross detected by the zero cross detection circuit 5, switching between Td1 + Td3 is stopped to perform full energization, and a switching timing between the switching circuit 3 and the flywheel circuit 4 is provided with a time difference between Td2 and Td4. Therefore, even if a detection error occurs in the voltage zero cross in the zero cross detection circuit 5 or an error occurs in the switching timing, the occurrence of surge can be reliably prevented, and a highly reliable single-phase motor control device can be obtained.

Tenth Embodiment Embodiment 10 of the present invention will be described below with reference to the drawings. 18 is a block diagram of a controller for a single-phase motor according to Embodiment 10 of the present invention. Instead of the switching transistors 9 and 10 shown in FIG. 1 and the diodes 13 and 14 connected in parallel, a MOS- FET21
It is configured by using a switching circuit 3 composed of 22 and 22.

The basic control operation here is the first embodiment.
Is the same as MOS-FET used here
Is a voltage-driven switching element, which is a low-loss element capable of high-speed switching. Another feature is that a parasitic diode exists between the drain and source terminals.

In this case, the switching circuit 3 has a MOS
Since -FET is used, high-speed switching becomes possible as compared with the circuit configuration using the transistor shown in FIG. 1, and when the switching frequency of the pulse signal generated by the oscillation circuit 6 is set to, for example, 20 kHz or higher than the audible frequency. As a result, a switching sound is not heard, and a control device for a single-phase motor with low noise and low vibration can be obtained.

Eleventh Embodiment An eleventh embodiment of the present invention will be described with reference to the drawings. Figure 1
9 is a block diagram of a control device for a single-phase motor according to Embodiment 11 of the present invention. Instead of the flywheel transistors 11 and 12 shown in FIG. 18 and the diodes 15 and 16 connected in parallel, a MOS- It is configured by using the flywheel circuit 4 including the FETs 23 and 24.

The basic control operation here is the first embodiment.
However, in this case, since the MOS-FET is used for the switching circuit 3 and the flywheel circuit 4, by using a parasitic diode built in between the drain and source terminals of the MOS-FET, Since the diodes 13 to 16 shown in 1 are unnecessary, the circuit can be simplified and the cost can be reduced. Further, in this configuration, circuit loss is low and energy saving can be realized as compared with a configuration using a transistor.

Twelfth Embodiment The twelfth embodiment of the present invention will be described below with reference to the drawings. 20 is a block diagram of a control device for a single-phase motor according to a twelfth embodiment of the present invention, in which a current value detecting means 25 for detecting a current value flowing in the single-phase induction motor 2 is added to the control device shown in FIG. It is a thing.

Next, the operation of this embodiment will be described. The basic control operation here is the same as that of the first embodiment. FIG. 21 shows operation timings of a current value flowing in the single-phase induction motor 2, drive waveforms of the switching transistors 9 and 10, and drive waveforms of the flywheel transistors 11 and 12. FIG. 21 is an operation timing chart of the control device for a single-phase motor according to Embodiment 12 of the present invention. In the figure, when the current value detected by the current value detecting means 25 exceeds a preset set value, When it is determined that current is flowing, the switching switching circuit 7 turns off the switching transistors 9 and 10,
The application of voltage to the single-phase induction motor 2 is stopped. When the detected current value becomes lower than the set value, the control operation shown in the first embodiment is performed again.

In this case, even if an overcurrent flows through the single-phase induction motor 2, the control device is protected, so that the circuit breakdown can be prevented and a highly reliable single-phase motor control device can be obtained. it can.

Thirteenth Embodiment The thirteenth embodiment of the present invention will be described with reference to the drawings. Figure 2
2 is a block diagram of a control device for a single-phase motor according to a thirteenth embodiment of the present invention. The oscillation circuit 6, the switching switching circuit 7, and the flywheel switching circuit 8 shown in FIG. 1 are microcomputers (hereinafter referred to as microcomputers). And a digital circuit 26 such as a logic circuit.

The basic control operation here is the first embodiment.
Is the same as The circuit configuration in this embodiment may be a configuration in which a MOS-FET is used instead of the transistor and the diode, and the current direction detecting means 19 shown in the fifth embodiment and the current value shown in the twelfth embodiment. A circuit configuration in which the detecting means 25 and the like are added may be used.

FIG. 23 is an operation timing chart of the control device for a single-phase motor according to the thirteenth embodiment of the present invention. The voltage waveform of the AC power supply 1, the voltage zero-cross signal detected by the zero-cross detection circuit 5, the switching and flywheel. The operation timings of the drive waveforms of the transistors 9 to 12 are shown.

In FIG. 23, after counting the voltage zero cross point A detected by the zero cross detection circuit 5 for Td5 by the timer of the microcomputer, the flywheel transistor 12 is turned on. Further, after counting Td7 by the timer from the point A, the switching transistor 10 is switched from the full conduction mode to the switching mode.

Further, the switching transistor 10 is switched to the full conduction mode after the point A to Td7 + Td8, and the flywheel transistor 12 is turned off after the point A to Td5 + Td6. The relational expressions at this time are shown in Expressions (4) and (5). Td7>Td5> 0 (4) T> Td5 + Td6> Td7 + Td8 (5)

Further, the switching operation of the switching transistor 9 and the flywheel transistor 11 from the voltage zero cross point B detected by the zero cross detection circuit 5 is carried out in the same manner as described above.

In this case, since the generation of the switching timing is controlled by using the timer of the microcomputer, the variation in time can be suppressed and the fine control becomes possible. Further, the oscillation circuit 6 and the switching switching circuit 7 shown in FIG.
Since the flywheel switching circuit 8 is unnecessary, the control circuit can be simplified, and the size and cost can be reduced.

Fourteenth Embodiment A fourteenth embodiment of the present invention will be described with reference to the drawings. Figure 2
4 is a block diagram of a control device for a single-phase motor according to a fourteenth embodiment of the present invention, in which a rotation speed detecting element 27 for detecting the rotation speed of the single-phase induction motor 2 is added to the control device shown in FIG. is there.

Next, the operation of this embodiment will be described. The basic control operation here is the same as that of the first embodiment. FIG. 25 shows the control flow of this system. In step 30, the rotation speed of the single-phase induction motor 2 is detected by the rotation speed detection element 27, and in step 31,
It is determined whether the detected rotation speed is equal to the target rotation speed. If they are not equal, it is determined in step 32 whether the detected rotation speed is higher than the target rotation speed. If it is higher, the on-duty is lowered in step 33, the process returns to step 30, and the operation is repeated. If the detected rotation speed is lower than the target rotation speed, the ON duty is increased in step 34, the process returns to step 30, and the operation is repeated again. In step 31, until the detected rotation speed becomes equal to the target rotation speed. , The same operation is repeated to return to the normal operation.

In this case, even if the torque of the load fluctuates,
A control device for a single-phase motor whose rotation speed does not fluctuate can be obtained.
Further, when the control device for a single-phase motor according to this embodiment is used for a blower such as an air conditioner or a ventilation fan, it is possible to perform control while keeping the air volume constant even if load change occurs.

Fifteenth Embodiment A fifteenth embodiment of the present invention will be described with reference to the drawings. Figure 2
6 is a graph showing a switching frequency (hereinafter, referred to as fsw) with respect to ON duty of a pulse signal of the oscillation circuit 6 of the controller for a single-phase motor according to Embodiment 15 of the present invention.

Next, the operation of this embodiment will be described. The basic control operation here is the same as that of the first embodiment. FIG. 27 shows a control flow of this system, and FIG. 28 shows fsw for ON Duty of the pulse signal. In step 40 of FIG. 27, it is determined whether to change the currently output ON duty. If there is no need to change, it returns to normal operation. If it needs to be changed, in step 41, fsw for the on-duty as shown in FIG. 28 is set, and in step 42
At, output the set ON Duty and fsw,
Return to normal operation.

When the on-duty is small, the number of rotations of the single-phase induction motor 2 is low and the rotation noise is small, so that the switching noise is very annoying. At this time, fsw is set to, for example, 20 kHz or higher, which is higher than the audible frequency, to prevent annoying switching sound from being generated. On D
When uty increases, the rotation noise of the single-phase induction motor 2 increases and it becomes difficult to hear the switching noise.
Energy can be saved by reducing sw to, for example, 15 kHz to reduce circuit loss due to switching of the switching circuit 3.

When the control device for a single-phase induction motor of this embodiment is used in a blower such as an air conditioner or a ventilation fan, the blowing sound becomes dominant rather than the rotation sound of the single-phase induction motor 2, and the blowing sound Is larger, fsw can be further reduced, and further energy saving can be achieved.

Sixteenth Embodiment The sixteenth embodiment of the present invention will be described with reference to the drawings. Figure 2
FIG. 9 shows a change in ON duty of the pulse signal of the oscillation circuit 6 at the time of starting the single-phase induction motor 2 of the single-phase motor controller according to the sixteenth embodiment of the present invention.

Next, the operation of this embodiment will be described. The basic control operation here is the same as that of the first embodiment. FIG. 30 shows the control flow of this system, and FIG. 31 shows the ON duty of the pulse signal with respect to the starting time. In step 50 of FIG. 30, the ON duty (Dx) is set according to the target rotation speed, and step 51
In step 52, the activation time Tn (n = 1) is set, and in step 52, ON duty (Dn) for the activation time Tn as shown in FIG. 31 is output. Then step 5
In step 3, Dn set in step 52 is changed to step 5
It is determined whether it is larger than Dx set by 0. If it is larger, the control flow at the time of startup is terminated and the normal operation is resumed.

If Dn is smaller than Dx, it is determined in step 54 whether Tn set in step 51 has passed, and Dn set in step 52 is continuously output until Tn passes. When Tn has elapsed, Tn is updated in step 55, the process returns to step 52, the operation is performed again, and the operation is repeated until Dn becomes larger than Dx in step 53.

In this case, if the single-phase induction motor 2 is started in a state where the ON duty is large, the current at the time of start-up may increase and the circuit may be destroyed. It is possible to suppress the current at the time, prevent the circuit from being broken, and obtain a highly reliable control device for a single-phase motor.

[0082]

As described above, according to the present invention, the circuit is simplified, and the size and cost can be reduced.

Further, it is possible to obtain a highly reliable device by preventing the occurrence of surge during the period when the polarities of voltage and current are different to reduce the circuit loss and preventing the circuit from being broken.

Further, by absorbing the surge between the terminals of the single-phase motor, the destruction of the circuit can be prevented and a highly reliable one can be obtained.

Furthermore, the actuator of the present invention can perform highly reliable single-phase motor control with low noise and low vibration.

[Brief description of drawings]

FIG. 1 is a block diagram of a control device for a single-phase motor according to a first embodiment of the present invention.

FIG. 2 is an operation timing chart of the control device for a single-phase motor according to the first embodiment of the present invention.

FIG. 3 is an operation timing chart of the control device for a single-phase motor according to the first embodiment of the present invention.

FIG. 4 is a block diagram of a control device for a single-phase motor according to a second embodiment of the present invention.

FIG. 5 is a block diagram of a control device for a single-phase motor according to a third embodiment of the present invention.

FIG. 6 is a block diagram of a control device for a single-phase motor according to Embodiment 4 of the present invention.

FIG. 7 is an operation timing chart of the control device for a single-phase motor according to the fourth embodiment of the present invention.

FIG. 8 is a block diagram of a control device for a single-phase motor according to a modification of the fourth embodiment of the present invention.

FIG. 9 is a block diagram of a control device for a single-phase motor according to a fifth embodiment of the present invention.

FIG. 10 is an operation timing chart of the control device for a single-phase motor according to the fifth embodiment of the present invention.

FIG. 11 is a block diagram of a control device for a single-phase motor according to a sixth embodiment of the present invention.

FIG. 12 is an operation timing chart of the control device for a single-phase motor according to Embodiment 7 of the present invention.

FIG. 13 is an operation timing chart of the control device for a single-phase motor according to the seventh embodiment of the present invention.

FIG. 14 is an operation timing chart of the control device for a single-phase motor according to Embodiment 8 of the present invention.

FIG. 15 is an operation timing chart of the control device for a single-phase motor according to Embodiment 8 of the present invention.

FIG. 16 is an operation timing chart of the control device for a single-phase motor according to the ninth embodiment of the present invention.

FIG. 17 is an operation timing chart of the control device for a single-phase motor according to the ninth embodiment of the present invention.

FIG. 18 is a block diagram of a control device for a single-phase motor according to a tenth embodiment of the present invention.

FIG. 19 is a block diagram of a control device for a single-phase motor according to an eleventh embodiment of the present invention.

FIG. 20 is a block diagram of a control device for a single-phase motor according to a twelfth embodiment of the present invention.

FIG. 21 is an operation timing chart of the control device for a single-phase motor according to Embodiment 12 of the present invention.

FIG. 22 is a block diagram of a control device for a single-phase motor according to a thirteenth embodiment of the present invention.

FIG. 23 is an operation timing chart of the control device for a single-phase motor according to the thirteenth embodiment of the present invention.

FIG. 24 is a block diagram of a control device for a single-phase motor according to a fourteenth embodiment of the present invention.

FIG. 25 is a control flowchart of the single-phase motor controller according to the fourteenth embodiment of the present invention.

FIG. 26 is a block diagram of a control device for a single-phase motor according to a fifteenth embodiment of the present invention.

FIG. 27 is a control flowchart of a single-phase motor controller according to Embodiment 15 of the present invention.

FIG. 28 is an explanatory diagram showing a switching frequency with respect to ON Duty of a pulse signal of the oscillation circuit of the control device for the single-phase motor according to the fifteenth embodiment of the present invention.

FIG. 29 is a block diagram of a control device for a single-phase motor according to Embodiment 16 of the present invention.

FIG. 30 is a control flowchart of a controller for a single-phase motor according to Embodiment 16 of the present invention.

FIG. 31 is a diagram showing an embodiment 16 of the present invention in which the pulse signal is turned on Du with respect to the start-up time of the control device for a single-phase motor.
It is explanatory drawing which shows ty.

FIG. 32 is a block diagram of a conventional AC voltage control device.

[Explanation of symbols]

1 AC power supply, 2 single-phase induction motor, 3 switching circuit, 4 flywheel circuit, 5 zero cross detection circuit, 6 oscillation circuit, 7 switching switching circuit, 8 flywheel switching circuit, 9 to 12 transistors, 13
˜16 diode, 17 transistor, 18 diode bridge, 19 current direction detecting means, 20 surge absorbing element, 21-24 MOS-FET, 25 current value detecting means, 26 digital circuit, 27 rotational speed detecting element.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Hirofumi Nishimura Inventor Hirofumi Nishimura 7-4, Ota-cho, Suma-ku, Kobe-shi, Hyogo Eldam Co., Ltd. (72) Osamu Nakazaki 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Co., Ltd. (56) Reference JP-A-6-105564 (JP, A) JP-A-7-67337 (JP, A) Actual development Sho 63-33398 (JP, U) (58) Fields investigated ( Int.Cl. ⁷ , DB name) H02M 5/293 H02P 5/28-5/44 H02P ^7/ 36-7/66

Claims (8)

(57) [Claims] 1. A switching circuit connected between an AC power supply and a single-phase motor so as to perform switching in both positive and negative directions at a frequency higher than a power supply frequency, and the single-phase so as to perform flywheeling in both positive and negative directions. Generates a pulse signal that is input to the flywheel circuit connected between the terminals of the motor and the main switching element of the switching circuit
An oscillator circuit that controls the switching circuit; a flywheel switching circuit that controls the switching element of the flywheel circuit based on the AC power supply voltage ;
Current direction detector for detecting the direction of current flowing in the phase motor
And a single step detected by the current direction detection means.
The polarity of the current flowing in the phase motor and the voltage of the AC power supply is reversed.
Switching circuit stops switching during the
The control device for a single-phase motor is characterized in that the oscillation circuit is controlled so as to be fully energized . 2. A switching circuit connected between an AC power supply and a single-phase motor so as to perform switching in both positive and negative directions at a frequency higher than the power supply frequency, and the single-phase so as to perform flywheeling in both positive and negative directions. A flywheel circuit connected between the terminals of the motor, a zero-cross detection circuit that detects the voltage of the AC power supply, and a pulse signal that is input to the main switching element of the switching circuit
And an oscillation circuit for controlling the switching circuit, the voltage detected by the zero-cross detecting circuit and a flywheel switching circuit for controlling the switching elements of the flywheel circuit, the zero crossing detected zero
Cross timing and switching of the flywheel switching circuit
A single-phase motor control device characterized in that it has a time difference from the timing . 3. The control device for a single-phase motor according to claim 1, wherein the switching circuit comprises a switching transistor and a diode bridge. 4. The control device for a single-phase motor according to claim 1, wherein the switching circuit is directly driven by the oscillation circuit. 5. A current direction detecting means for detecting a direction of a current flowing through the single-phase motor is provided, and in a period in which the polarity of the current flowing through the single-phase motor detected by the current direction detecting means and the voltage of the AC power source is reversed. The control device for a single-phase motor according to claim 2 , wherein the switching circuit is stopped so that the oscillation circuit is controlled so as to be fully energized. 6. The controller for a single-phase motor according to claim 1, further comprising a surge absorbing element that absorbs a surge of the single-phase motor between terminals of the single-phase motor. 7. An actuator using the control device for a single-phase motor according to any one of claims 1 to 6. 8. A blower using the controller for a single-phase motor according to claim 1.