JPH08251984A - Controller for single phase induction motor - Google Patents

Abstract

PURPOSE: To obtain a controller for single phase induction motor in which vibration and noise caused by transient variation in torque can be reduced at the time of starting or stopping the induction motor. CONSTITUTION: A single phase induction motor 1 comprises main winding M and auxiliary winding A. The controller for the single phase induction motor comprises a sensor VT for detecting the power supply voltage, and a relay controller RC taking charge of the operation control. The relay controller RC contains a data related to the delay angle of main winding current IM from the power supply voltage under locked state and applies the power supply with a delay angle, determined based on the output from the sensor VT, from zero point of the power supply voltage or the vicinity thereof.

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 induction motor used in refrigerators and refrigerators typified by air conditioners (air conditioners).

[0002]

2. Description of the Related Art Conventionally, a single-phase induction motor of this type has been disclosed in, for example, Japanese Patent Laid-Open No. 122992/1993 (H02P7 / 63).
As shown in 2), it can be driven by a commercial single-phase 100V, and because it is robust, has a long service life, and has low cost, it is widely used for driving compressors such as refrigerators and air conditioners. There is. Hereinafter, the conventional general single-phase induction motor 100 will be described with reference to the electric circuits of FIGS.
Will be explained.

In FIG. 8, a single-phase induction motor 100 is provided with a main winding M and an auxiliary winding A. The single-phase induction motor 100 is connected to the auxiliary winding A in series. Capacitor CR, starting capacitor CS and starting relay switch S connected in parallel with this operating capacitor CR
A series circuit with W2 and a power relay switch SW1 for controlling power application to the single-phase induction motor 100 are provided.

Such a single-phase induction motor 100 has a single-phase alternating current 10
The single-phase induction motor 10 is connected to the 0V power supply AC.
At the start of 0, the start relay switch SW2 is closed. Therefore, a parallel circuit of the operating capacitor CR and the starting capacitor CS is connected to the auxiliary winding A, and when the power relay switch SW1 is closed, the single-phase induction motor 100 starts with a large starting torque. After that, the synchronous speed of 8
At about 0%, the starting relay switch SW2 is opened, the starting capacitor CS is disconnected from the circuit, and thereafter the single-phase induction motor 100 is driven by the current phase difference between the main winding M and the auxiliary winding A due to the operating capacitor CR. It was to continue driving.

FIG. 9 shows a circuit in which only the operating capacitor CR is connected to the auxiliary winding A without using the starting capacitor CS. The starting characteristic is not so good, but the starting relay switch SW2 and other elements can be omitted. It was used for equipment with relatively small starting torque.

Further, in FIG. 10, a positive temperature coefficient solid-state element PTC is connected to the auxiliary winding A instead of the starting capacitor CS and the starting relay switch SW2. This positive temperature coefficient solid-state element PTC is a semiconductor element whose resistance value increases in proportion to temperature, and when the single-phase induction motor 100 is started,
Since the temperature of the positive temperature coefficient solid state element PTC is low and the resistance value is also low, a large current flows through the auxiliary winding A to start the operation.

By this energization, the positive temperature coefficient solid-state element PT
Since C self-heats and its resistance value increases, the current flowing through the positive temperature coefficient solid-state element PTC decreases drastically. Therefore, after that, the single-phase induction motor 100 continued to operate due to the current phase difference between the main winding M and the auxiliary winding A due to the operating capacitor CR.

Further, FIG. 11 shows a case where the starting relay switch SW2 of FIG. 8 is replaced with the positive temperature coefficient solid state element PTC, and FIG. 12 shows a positive temperature coefficient solid state element PT of FIG.
A starting relay switch SW2 is connected to C so that the positive temperature coefficient solid-state element PTC is completely disconnected from the circuit after completion of starting.

[0009]

Here, the power supply AC
(Hereinafter, referred to as power supply voltage) V, a current flowing through the main winding M (hereinafter, referred to as main winding current) IM, and an auxiliary winding A
A current (hereinafter, referred to as an auxiliary winding current) IA and a circuit current I, which is the sum thereof, are sine waves having different phases. Conventionally, these currents are generated when the single-phase induction motor 100 is started. The power relay switch SW1 was closed regardless of each value.

Therefore, for example, when the power relay switch SW1 is closed at the time when the main winding current IM reaches the maximum value, the transient torque at the time of starting becomes abnormally large, and as a result, the single-phase induction motor 100 and the compressor. There was a problem that vibration and noise at the time of starting the vehicle increased.

Similarly, when the single-phase induction motor 100 is stopped, the power supply relay switch SW1 is conventionally circuited irrespective of the value of each voltage or current, so that the power supply is turned on at the time when the main winding current IM reaches its maximum value, for example. When the relay switch SW1 is opened, the torque suddenly drops from a large value to zero, so that there is a problem that the vibration and noise of the single-phase induction motor 100 and the compressor also increase.

The present invention has been made in order to solve the above-mentioned conventional technical problems, and is a single-phase induction capable of reducing the generation of vibration and noise due to a transient torque change at the time of starting or stopping. An object is to provide a control device for an electric motor.

[0013]

A control device according to the invention of claim 1 is applied to a single-phase induction motor having a main winding and an auxiliary winding, and controls a voltage detecting means for detecting a power supply voltage and an operation control. And a control means, the control means having data on a delay angle of the main winding current from the power supply voltage in a restrained state, based on the output of the voltage detection means,
The power supply is applied with a delay of the delay angle from zero or near zero of the power supply voltage.

A control device according to a second aspect of the present invention is applied to a single-phase induction motor having a main winding and an auxiliary winding, and includes a current detecting means for detecting a main winding current and a control means for controlling operation. This control means cuts off the power supply at or near zero of the main winding current based on the output of the current detection means.

A control device according to a third aspect of the invention is applied to a single-phase induction motor having a main winding and an auxiliary winding, and a voltage detecting means for detecting a power supply voltage and a current detecting for detecting the main winding current. Means and control means for controlling the operation, the control means has data on the delay angle of the main winding current from the power supply voltage in the restrained state, the output of the voltage detection means. Based on this, the power supply is applied with the delay angle delayed from the power supply voltage at or near zero, and the power supply is cut off at or near zero of the main winding current based on the output of the current detection means.

[0016]

According to the control device for a single-phase induction motor of the present invention, the control means has data relating to the delay angle of the main winding current from the power supply voltage in the restrained state, and the control means of the voltage detection means. Based on the output, the power supply is applied with a delay angle from or near zero of the power supply voltage, so that the main winding current starts to flow from zero or a value near zero when the single-phase induction motor is started. Therefore, abnormal transient torque is not generated, and it is possible to reduce vibration and noise at the time of starting.

According to the control device for a single-phase induction motor of the second aspect of the invention, the control means cuts off the power supply at or near zero of the main winding current based on the output of the current detection means, so that the torque is generated. It is possible to make the main winding current, which has a large contribution, to zero or near zero at this point, and to make a small torque by only the auxiliary winding current. Therefore, the torque change at the time of power interruption becomes a small change from the torque to zero due to only the auxiliary winding current, and the vibration and noise at the time of stop can be reduced.

According to the control device for a single-phase induction motor of the third aspect of the invention, the control means has data relating to the delay angle of the main winding current from the power supply voltage in the restrained state,
Based on the output of the voltage detection means, while applying the power supply with a delay angle of zero or near zero of the power supply voltage,
Since the power supply is cut off at or near zero of the main winding current based on the output of the current detection means, the transient torque at the time of starting and stopping the single-phase induction motor is reduced to significantly reduce vibration and noise. It is possible.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 shows an electric circuit diagram of a single-phase induction motor 1 according to an embodiment of the present invention. In the following drawings, the same reference numerals as those in FIGS. 8 to 12 are the same. In FIG.
The single-phase induction motor 1 drives a compressor included in a refrigeration cycle of a refrigerator (refrigerator) not shown, and includes a main winding M and an auxiliary winding A. Is connected to the auxiliary winding A in series, a series circuit of a starting capacitor CS and a starting relay switch SW2 connected in parallel to the operating capacitor CR, and to the single-phase induction motor 1. A power relay switch SW1 for controlling power application is provided.

The single-phase induction motor 1 is a single-phase alternating current (60H
z) Connected to 100V power supply AC. Further, CT is a sensor (current transformer) as a current detecting means for detecting the main winding current IM flowing in the main winding M, and VT is a sensor (transformer) for detecting the power supply voltage V of the power supply AC. RC is a relay controller composed of a general-purpose microcomputer as a control means.

The output data relating to the values of the main winding current IM and the power supply voltage V detected by the sensors CT and VT are input to the relay controller RC, and the relay controller RC also causes the relay switches SW1 and SW to be switched.
2 is opened and closed. The relay controller RC is also connected to a refrigerator internal temperature sensor (not shown) that detects the refrigerator internal temperature.

The operation of the above configuration will be described below. Here, FIG. 2 shows the power supply voltage V and each waveform of the circuit current I, the main winding current IM, and the auxiliary winding current IA of the single-phase induction motor 1 of the present embodiment when the restrained state is continuously stabilized. Cage,
In this case, V = 141 sin θ (V), I = 22.6 si
n (θ−25 °), IM = 21.2 sin (θ−45
), IA = 8.5 sin (θ + 45 °) has been experimentally measured. That is, the delay angle (electrical angle) of the main winding current IM from the power supply voltage V is 45 °, and this data is stored in the relay controller RC.

Now, assuming that the single-phase induction motor 1 is stopped, the starting relay switch SW2 is closed, and when the refrigerator internal temperature rises from that state to reach a predetermined upper limit temperature, the above-mentioned An operation command is issued from the internal temperature sensor (actually, this command is generated inside the relay controller RC). At this time, the relay controller R
C monitors the power supply voltage V based on the output of the sensor VT, and when the operation command is issued, from the time when the power supply voltage V becomes zero or near zero, the delay angle (45 ° ), The power relay switch SW1 is closed.

When the power relay switch SW1 is closed, current begins to flow in the main winding M and the auxiliary winding A, and
The auxiliary winding A has a starting capacitor CS and an operating capacitor C.
Since the R parallel circuit is connected, the single-phase induction motor 1 starts with a required starting torque. The relay controller RC opens the starting relay switch SW2 when the speed is increased to about 80% of the synchronous speed, and disconnects the starting capacitor CS from the circuit.

When the single-phase induction motor 1 is started, the power supply relay switch SW is delayed by the delay angle (45 °) from the time when the power supply voltage V becomes zero or near zero as described above.
1 is closed, the main winding current IM is
Starts flowing at or near zero. Therefore, at the moment when the power relay switch SW1 is closed, an abnormal transient torque unlike the conventional one is not generated, and the vibration and noise of the single-phase induction motor 1 and the compressor at the time of starting can be reduced.

The circuit current I and the main winding current I during the operation (load operation) of the single-phase induction motor 1 thus started.
M, auxiliary winding current IA is shown in FIG. 3, where V = 141 sin θ (same), I = 4.2 sin (θ−
15 °), IM = 2.8 sin (θ-55 °), IA =
It becomes 1.4 sin (θ + 30 °).

When the inside temperature of the refrigerator drops and reaches a predetermined lower limit temperature, an operation stop command is issued from the inside temperature sensor (actually, this command is generated inside the relay controller RC). . At this time, the relay controller RC monitors the main winding current IM based on the output of the sensor CT, and when the operation stop command is issued, the main winding current IM is zero or zero in FIG. Power relay switch SW1 when it is near
Open the circuit.

As a result, the power supply to the main winding M and the auxiliary winding A is cut off, so that the single-phase induction motor 1 is stopped, but the relay controller RC causes the main winding current I as described above.
Power relay switch SW at or near zero of M
Since 1 is opened, the main winding current IM, which has a large contribution to torque generation, can be zero or near zero at this point (disconnection), and a small torque can be obtained only by the auxiliary winding current IA. Therefore, the torque change at the time of power interruption becomes a small change from the torque to zero due to only the auxiliary winding current IA, and the vibration and noise of the single-phase induction motor 1 and the compressor at the time of stop can be reduced.

Next, FIG. 4 shows an electric circuit of the single-phase induction motor 1 in which the present invention is applied to the system shown in FIG.
FIG. 5 shows the electric circuit of the single-phase induction motor 1 to which the present invention is applied to the system of FIG. 10 described above, and FIG. 6 shows the electric circuit of the single-phase induction motor 1 to which the present invention is applied to the system of FIG. The electric circuits are shown respectively. The same reference numerals are used in the drawings. In this case as well, the operation of the relay controller RC at the time of starting and stopping is the same as that described above, but of course the starting relay switch SW2 is not controlled.

FIG. 7 shows an electric circuit of the single-phase induction motor 1 to which the present invention is applied to the system of FIG. 12 described above. In this case, the relay controller RC is the same as that described above (FIG. 1). It controls.

[0031]

As described in detail above, according to the invention of claim 1, the control means has data concerning the delay angle of the main winding current from the power supply voltage in the restrained state, and the output of the voltage detection means. On the basis of the above, since the power supply is applied with a delay angle from the zero or near zero of the power supply voltage, the main winding current starts to flow from zero or a value near zero when the single-phase induction motor is started. Therefore, abnormal transient torque is not generated, and it is possible to reduce vibration and noise at the time of starting.

According to the invention of claim 2, the control means cuts off the power supply at or near zero of the main winding current based on the output of the current detection means, so that the main winding having a large contribution to torque generation. The current can be zero or near zero at this time, and a small torque due to only the auxiliary winding current can be obtained. Therefore, the torque change at the time of power interruption becomes a small change from the torque to zero due to only the auxiliary winding current, and the vibration and noise at the time of stop can be reduced.

According to the third aspect of the present invention, the control means has data on the delay angle of the main winding current from the power supply voltage in the restrained state, and the power supply voltage is zero based on the output of the voltage detection means. Alternatively, the power is applied with a delay of the delay angle from around zero, and the power is cut off at or near zero of the main winding current based on the output of the current detection means. It is possible to reduce the transient torque at the time of stoppage and significantly reduce vibration and noise.

[Brief description of drawings]

FIG. 1 is an electric circuit diagram of a single-phase induction motor of the present invention.

FIG. 2 is a diagram showing waveforms of a power supply voltage, a circuit current, a main winding current, and an auxiliary winding current when the restrained state of the single-phase induction motor of the embodiment is continuously stabilized.

FIG. 3 During operation of the single-phase induction motor of the embodiment (load operation)
6 is a diagram showing waveforms of a power supply voltage, a circuit current, a main winding current, and an auxiliary winding current in FIG.

FIG. 4 is another electric circuit diagram of the single-phase induction motor of the present invention.

FIG. 5 is still another electric circuit diagram of the single-phase induction motor of the present invention.

FIG. 6 is yet another electric circuit diagram of the single-phase induction motor of the present invention.

FIG. 7 is yet another electric circuit diagram of the single-phase induction motor of the present invention.

FIG. 8 is an electric circuit diagram of a conventional single-phase induction motor.

FIG. 9 is another electric circuit diagram of a conventional single-phase induction motor.

FIG. 10 is still another electric circuit diagram of the conventional single-phase induction motor.

FIG. 11 is still another electric circuit diagram of the conventional single-phase induction motor.

FIG. 12 is still another electric circuit diagram of the conventional single-phase induction motor.

[Explanation of symbols]

 1 Single-phase induction motor A Auxiliary winding CR Operating capacitor CT, VT Sensor M Main winding RC Relay controller SW1 Operating relay switch SW2 Starting relay switch

Claims (3)

[Claims] 1. A single-phase induction motor having a main winding and an auxiliary winding, comprising voltage detection means for detecting a power supply voltage and control means for controlling operation, the control means comprising the power supply in a restrained state. It has data on the delay angle of the main winding current from the voltage, and based on the output of the voltage detection means, applying the power source with a delay of the delay angle from or near zero of the power source voltage. The control device for the characteristic single-phase induction motor. 2. A single-phase induction motor having a main winding and an auxiliary winding, comprising current detection means for detecting the main winding current, and control means for controlling operation, the control means comprising: A control device for a single-phase induction motor, characterized in that the power supply is cut off at or near zero of the main winding current based on the output of the detection means. 3. In a single-phase induction motor having a main winding and an auxiliary winding, voltage detecting means for detecting a power supply voltage, current detecting means for detecting the main winding current, and control means for controlling operation. The control means has data relating to the delay angle of the main winding current from the power supply voltage in the restrained state, and based on the output of the voltage detection means, from zero or near zero of the power supply voltage. While applying the power source with a delay by the delay angle, based on the output of the current detection means,
A controller for a single-phase induction motor, characterized in that the power supply is cut off at or near zero of the main winding current.