JP2003079190A - Motor controller, oxygen rich device and method for driving motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a motor controller realizing power saving operation, an oxygen rich device and a method for driving a motor. SOLUTION: The motor control circuit for an oxygen rich device comprises a power regulation circuit 12 for regulating AC power being fed to an induction motor 10, and a control circuit 13 for controlling the power regulation circuit such that the motor 10 is driven with maximum power for a predetermined time after start and then driven with predetermined low power or at a predetermined number of revolutions. According to the invention, a power saving operation can be realized through a simple arrangement. Furthermore, the vibration of the motor is reduced and a small cooling fan can be used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control device, an oxygen enrichment device, and a motor driving method, and more particularly to a motor control device, an oxygen enrichment device, and a motor capable of achieving power saving with a simple structure. The present invention relates to a driving method.

[0002]

2. Description of the Related Art Conventionally, an oxygen enrichment apparatus using a known oxygen enrichment membrane has been proposed, and an induction motor is used as a motor for a vacuum pump that sucks air through the oxygen enrichment membrane. It was

[0003]

In the above-described conventional oxygen enrichment apparatus, the motor for the vacuum pump needs a large torque only at the time of start-up and the early stage when there is much air to be exhausted, after the degree of vacuum is increased. Since the resistance (work load) is reduced during steady rotation of, the torque is almost unnecessary. However, when using an induction motor,
Due to its characteristics, the current flowing through the motor remains almost the same regardless of the size of the load, and there is a problem that more than half of the power consumption is wasted as heat when the load is low.

An object of the present invention is to solve the above-mentioned problems of the prior art, and to reduce the drive power of the motor to a power level at which operation can be maintained after a preset time has elapsed from the start of driving the vacuum pump. Accordingly, it is an object of the present invention to provide a motor control device, an oxygen enrichment device, and a motor driving method that enable operation with low power consumption.

[0005]

The motor control device of the present invention comprises a power adjusting means for adjusting the AC power supplied to the induction motor, the induction motor being driven at the maximum power for a predetermined time from the start, and then the maximum. And a control means for controlling the electric power adjusting means so that the electric power is driven at a predetermined electric power smaller than the electric power or the rotational speed becomes a predetermined rotational speed.

According to the present invention, the electric power can be saved with a simple structure by reducing the electric power so that the operation can be maintained after the preset time has elapsed. Furthermore, the vibration of the motor is reduced, and a small cooling fan can be used, which also saves power and improves quietness.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below. FIG. 1 is a block diagram showing the configuration of an oxygen enrichment device to which the present invention is applied. An induction motor is used as the motor 10 for the vacuum pump 22. The drive circuit 12 controls the drive power of the motor 10 under the control of the control circuit 13. The control circuit 13
For example, it is a well-known one-chip computer having a CPU, a ROM, a RAM, an analog (A / D converter) and a digital I / O port.

The control circuit 13 uses the phase detection circuit 17 to detect the phase of the power source (zero cross point) based on the program stored in the ROM, and uses the sensor 11 to detect the rotational speed of the motor 10. To do. Further, the operation information of the user is detected from the panel 14, and the drive circuit 12 is controlled based on the detected information.

FIG. 2 shows an oxygen enrichment device 2 to which the present invention is applied.
It is sectional drawing which shows the structure of 0. Further, FIG. 3 is a sectional view showing the structure of the oxygen-enriched film. Oxygen enriched membrane unit 21
Is a stack of a plurality of sheet-shaped oxygen-enriched films with a gap therebetween. As shown in FIG. 3, the oxygen-enriched membrane is formed by stacking a non-porous separation membrane 30 having a higher oxygen permeability than nitrogen, a porous support membrane 31, and a communicating foam 32 as shown in FIG. , The communicating foam 32 of a plurality of oxygen-enriched membranes is the pipe 3
3 and is connected to the vacuum pump 22.

The output of the vacuum pump 22 is output to the outside as oxygen-enriched air 26 via a cooling pipe 23 and a water aggregating tank 25. The cross-flow fan 24 is an electric fan, and by driving this fan, intake air passes through the gap of the oxygen-enriching membrane unit 21 to constantly send new air to the surface of the oxygen-enriching membrane to improve enrichment efficiency. The cooling pipe 23 and the vacuum pump 22 are cooled and exhausted while being improved.

The operation will now be described. When the vacuum pump 22 and the cross flow fan 24 are operated,
The air pressure inside the membrane (communication foam 32) decreases, and the air outside the oxygen-enriched membrane 30 permeates into the interior (communication foam 32). At this time, since the non-porous separation membrane 30 has a higher oxygen permeability than nitrogen, oxygen-enriched air having an oxygen concentration higher than that of air (for example, an oxygen concentration of 30%) is generated inside. The generated oxygen-enriched air is cooled, separated from water, and output. For example, a person can inhale this oxygen-enriched air to supplement the oxygen deficiency.

After a lapse of a predetermined time from the start of operation of the apparatus, the air pressure inside the membrane 32 is almost constant (for example, 500 mmHg).
Degree). The vacuum pump 22 is usually driven by an induction motor. However, a large output is required for the motor only at the moment of start-up and during the time when a large amount of air is exhausted, the vacuum pump 22 is degassed from the inside of the oxygen-enriched membrane and the vacuum If the load rises, the work load decreases (resistance decreases) during the subsequent steady operation, so the load decreases. Then, almost half of the current flowing through the motor is wasted as heat, which is wasted.

What has been considered there is a control method of the present invention, in which the drive power is reduced when the workload is reduced to reduce unnecessary power consumption. As a result of the experiment, for example, when the motor is driven at a normal voltage of 100 V during steady operation, the motor speed is 1,780 rpm and the power consumption is 137 W, but it is possible to maintain the rotation even if the drive voltage is reduced to 50 V. , The rotation speed at this time is 1,740 rpm, and the power consumption drops to 70W.

FIG. 4 is a circuit diagram showing a part of the circuit of the oxygen enrichment apparatus to which the present invention is applied. A current switching circuit 12, which is a power adjusting means, is connected in series with the induction motor 10. Although well-known triacs and diacs are used in the illustrated circuits, any well-known elements and circuits can be used as switching elements and power control circuits.

To the power source, a phase (zero cross timing) detection circuit 17 of a power source voltage for generating a pulse at zero cross timing is connected. Further, a magnet is mounted on the shaft of the motor 10, and a sensor IC 11 including a Hall effect element that detects a magnetic force line of the magnet is arranged near the shaft on which the magnet is mounted. The sensor is a motor 1
Generate one or a predetermined number of pulses per revolution.

FIG. 7 is a waveform diagram showing a motor drive waveform example of the oxygen enrichment apparatus to which the present invention is applied. Control circuit 11
Detects a zero-cross timing pulse from the phase detection circuit 17, measures a predetermined time by a built-in timer, and then outputs a drive signal for turning on the switching element until the next zero-cross timing pulse. As a result, the motor 1 has a waveform as shown in the lower part of FIG.
0 is driven. The drive waveform does not become a sine curve, but since the induction motor is an inductive load,
By changing the measurement time of the timer, the same electric power control as that when the motor drive voltage is changed becomes possible.

FIG. 5 is a flow chart showing the operation (1) of the control circuit of the oxygen enrichment apparatus to which the present invention is applied. The flowchart of FIG. 5 shows the first embodiment for detecting and controlling the rotation speed of the motor. The induction motor basically rotates in synchronization with the frequency of the power supply, but the rotation speed slightly changes depending on the magnitude of the load, drive voltage, and the like. The present invention utilizes this slight change in the rotational speed.

When the power switch is turned on, the timer value and the like are initialized in S10, and when the start operation is detected in S11, the built-in timer is set for a predetermined time to start, and then in S12, the motor is fully powered. To drive. That is, the SCR (switching element) drive signal is output in the on state immediately after the zero-cross detection.

In S13, it is determined by the state of the timer whether or not a predetermined time has elapsed. If the determination result is negative, the process returns to S12, but if the determination result is affirmative, the process proceeds to S14. In S14, the motor rotation speed is detected. Since the rotation speed of the motor is inversely proportional to the pulse interval from the sensor 11, the pulse interval processing is used to measure the pulse interval separately from the processing of FIG. 5, and the rotation speed is calculated from the measured value. The calculated value is read in S14.

In S15, it is determined whether or not the current rotational speed is less than or equal to a predetermined lower limit rotational speed. The lower limit value is set to a value slightly larger than the rotation speed at which the rotation cannot be maintained and the rotation is stopped when the rotation speed is further reduced. If the determination result is affirmative, the process proceeds to S16 and the drive power is increased. That is, in FIG. 7, the timing for turning on the switching element is advanced by a predetermined value.

In S17, it is determined whether or not the current rotation speed is equal to or higher than a predetermined upper limit rotation speed. The upper limit value may be set to a value larger than the lower limit value by a predetermined amount, or may be the same as the lower limit value. When the determination result is affirmative, the process proceeds to S18, and the drive power is reduced. That is, in FIG. 7, the timing of turning on the switching element is delayed by a predetermined value.

In S19, it is determined whether or not to end after a predetermined time has elapsed. If it is not ended, the process returns to S14, but if it is ended, the process proceeds to S20. In S20, the drive of the motor is stopped, and S1
Return to 1.

In the first embodiment, the rotation speed of the motor is feedback-controlled to output the lowest voltage capable of maintaining rotation so that the rotation speed is always constant. Therefore, the first
According to the method of the embodiment, it is possible to set the voltage down to the limit without worrying about the fluctuation of the power supply voltage, and a high power saving effect can be obtained.

FIG. 6 is a flow chart showing the operation (2) of the control circuit of the oxygen enrichment apparatus to which the present invention is applied. The flowchart of FIG. 6 does not detect the rotation speed of the motor,
The 2nd Example driven by the predetermined reduction power is shown. Since S30 to S33, S38, and S39 are the same as S10 to S13, S19, and S20 of the first embodiment, respectively, only different portions will be described.

In S34, the control circuit 13 controls the drive circuit 12 to drive the motor 10 with the reduced power. That is, the timing for turning on the switching element in FIG. 7 is delayed by a predetermined value. The ON delay amount is determined in advance by experiments. That is, the on-delay amount is set to a small value with a certain margin from the timing at which the rotation cannot be maintained and the rotation is stopped when the power is further reduced (the on-delay amount is increased = slow). This is to prevent the motor from stopping even if the power supply voltage fluctuates.

In S35, it is determined whether or not the motor has stopped. As a determination method, for example, it is possible to detect the stop of the motor by measuring the pulse interval using the same sensor 11 as that of the first embodiment, and any other known motor stop detection means may be used. It can be used. If the determination result is stop, S
Move to 36.

In S36, the driving of the motor is stopped and a timer is used to wait for a predetermined time. The reason for waiting is that if the motor stops during operation, the vacuum pump will be sucked to top dead center and stop due to the negative pressure, and the air cannot permeate through the oxygen-enriched membrane because it cannot start due to the negative pressure. This is because it is necessary to wait only for the time when the negative pressure decreases. S37
In S3, after driving at full power for a predetermined time, S3
Return to 4 and continue operation.

The second embodiment can be carried out with a simpler construction than the first embodiment, but it must be set to a slightly higher power in anticipation of fluctuations in the supply voltage. The power saving effect is a little lower than the comparison. Note that S35 to S37
An example in which the motor stop detection means is omitted is also possible,
In this case, the configuration is further simplified, but it is necessary to set the power to be higher than that in the second embodiment, and the power saving effect is further reduced.

Although the embodiments of the present invention have been disclosed above, the following modifications can be considered in the present invention. In the embodiment, the example in which the rotation is detected by the Hall element is disclosed, but any known means for detecting the rotation speed or rotation / stop of the motor, such as a combination of a magnet and a coil, a rotating plate and a photo interrupter, and a tacho generator. Is available. As an example, the example in which the motor is driven at full power until a predetermined time has elapsed and then the power is reduced is disclosed. However, for example, the rotational speed is gradually increased in a plurality of stages or continuously in accordance with the elapsed time from the start of operation. May be dropped.

Although the example of controlling the on-timing of the switching element has been disclosed as the power adjusting means, it is consumed by inserting / shorting an impedance element such as a resistor or a coil in series with the motor using, for example, a relay. The power may be changed. Although an example in which the present invention is applied to an oxygen enrichment device has been disclosed in the embodiments, the present invention discloses that the motor of any device in which the load is heavy only at the time of starting the device and thereafter the state of the light load continues. It is applicable to control of.

[0031]

As described above, according to the present invention,
After starting the driving of the vacuum pump and elapse of a preset time, the driving electric power is reduced to the electric power capable of maintaining the operation, so that there is an effect that the operation can be performed with low power consumption. Further, in the present invention, it is possible to use an induction motor and a simple electric power adjusting means, and there is also an effect that the object can be achieved at a low cost without using an expensive inverter control or a three-phase motor. Furthermore, since the vibration of the motor is reduced by reducing the power, the quietness is improved,
Since the cooling fan is also small, it is sufficient to save power.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an oxygen enrichment device to which the present invention is applied.

FIG. 2 is a cross-sectional view showing the configuration of an oxygen enrichment device 20 to which the present invention is applied.

FIG. 3 is a cross-sectional view showing the structure of an oxygen-enriched film.

FIG. 4 is a circuit diagram showing a part of a circuit of an oxygen enrichment device to which the present invention is applied.

FIG. 5 is a flowchart showing an operation (1) of the control circuit of the present invention.

FIG. 6 is a flowchart showing an operation (2) of the control circuit of the present invention.

FIG. 7 is a waveform diagram showing a motor drive waveform example of the present invention.

[Explanation of symbols]

10 ... Motor, 11 ... Sensor, 12 ... Driving circuit, 13
... control circuit, 14 ... panel, 15 ... power switch, 16
… Power supply, 17… Phase detection circuit, 20… Oxygen enrichment device, 2
1 ... Oxygen-enriched membrane unit, 22 ... Vacuum pump, 23 ... Cooling pipe, 24 ... Cross flow fan, 25 ... Moisture coagulation tank, 26 ... Oxygen-enriched air

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H02P 5/402 301 F04B 49/02 331B (72) Inventor Kenji Ishizuka 550, Hirodori, Hachimanji, Fujieda City, Shizuoka Prefecture 1 Stock term in Maruka stock company (reference) 3H045 AA05 AA12 AA26 BA03 BA07 BA32 CA09 CA21 DA01 DA47 EA04 EA17 EA35 EA36 3H076 AA16 AA21 BB21 BB36 CC07 5H575 AA20 BB02 BB04 EE05 FF07 FF08 HA14JJ

Claims (5)

[Claims] 1. An electric power adjusting means for adjusting the AC electric power supplied to the induction motor, wherein the induction motor is driven at a maximum electric power for a predetermined time after starting, and thereafter, is driven at a predetermined electric power smaller than the maximum electric power. A motor control device comprising: a control unit that controls the power adjusting unit. 2. An electric power adjusting means for adjusting the AC electric power supplied to the induction motor, a rotation speed detecting means of the induction motor, and driving the induction motor at the maximum electric power for a predetermined time from the start, and thereafter performing a predetermined rotation. A motor control device comprising: a control unit that controls the power adjustment unit so as to maintain the number. 3. The rotation stop detecting means for the induction motor is further provided, and when the control means detects the rotation stop for the induction motor, the control means stops the driving of the induction motor for a predetermined time, and thereafter, 3. The motor control device according to claim 1, wherein the electric power adjusting means is controlled so that the induction motor is driven with the maximum electric power for a predetermined time. 4. An oxygen enrichment device, characterized in that an oxygen enrichment membrane is used, and the motor control device according to any one of claims 1 to 3 is used for controlling a suction pump motor. 5. A step of driving an induction motor with maximum electric power for a predetermined time after start-up, a predetermined electric power smaller than the maximum electric power, or an electric power such that the motor maintains a predetermined rotational speed. And a step of driving the motor.