JP3246333B2 - Air conditioner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner in which an outdoor fan is driven by a DC brushless motor.

[0002]

2. Description of the Related Art In order to improve the operation efficiency of an air conditioner,
The conversion of the fan drive motor from a conventional induction motor to a DC brushless motor has been performed. In particular, in a separate type air conditioner, many of the indoor fans have already been driven by a DC brushless motor, and a DC brushless motor for an outdoor fan has been developed in succession.

However, as a drive motor for an outdoor fan, D
In the case of using a C brushless motor, when the outdoor fan is forcibly driven by an external force such as a back wind or the like, power is generated by rotation of the motor, which may destroy a power transistor or the like of the motor drive circuit.
Therefore, in order to solve such a problem, a DC voltage applied to the motor drive circuit is detected, and if the DC voltage is equal to or more than a predetermined value, the DC brushless motor and the motor drive circuit can be disconnected by a relay or the like. This is conventionally performed (for example, Japanese Patent Application Laid-Open No. 63-103621).

FIG. 4 shows a basic configuration relating to a motor drive of the conventional air conditioner. In FIG.
Reference numeral 8 denotes an AC power supply.
9, the input side of the first DC power supply 31 and the second DC power supply 4
1 is connected to the input side. The output terminal of the first DC power supply 31 has positive and negative power supply paths 33a, 33b of a first drive circuit 33 for driving a compressor motor 35.
And positive and negative power supply paths 34a, 3d of a second drive circuit 34 for driving a DC brushless motor 36 for an outdoor fan.
4b is connected. On the other hand, the second DC power supply 41
Is connected to the input side of the switching power supply 32. The switching power supply 32 supplies power to a control unit 37 including functions of a microcomputer. In the figure, reference numeral 40 denotes a relay, which opens and closes between the DC brushless motor 36 and the second drive circuit 34. And these relays 40,
The first drive circuit 33 and the second drive circuit 34 are controlled by the control unit 37. Further, in the figure, 31a is a smoothing capacitor provided between the output terminals of the first DC power supply 31, and 41a is a second capacitor.
A similar smoothing capacitor provided in the DC power supply 41.

In the above conventional air conditioner, the voltage between the positive and negative power supply paths 34a and 34b of the second drive circuit 34 is detected, and when this voltage exceeds a certain value, the control unit 37 turns off the relay 40 for a certain time. . By doing so, it is possible to prevent an excessive current generated by the rotation of the DC brushless motor 36 due to an external force such as a reverse wind from flowing to the first drive circuit 33 or the second drive circuit 34 and destroying the power transistor and the like. It was like.

[0006]

However, in the above-described conventional air conditioner, it is necessary to operate the control unit 37 in order to protect the drive circuits 33 and 34.
It is necessary to always connect the AC power supply 38 to operate the second DC power supply 41, and to continuously supply power from the switching power supply 32 to the control unit 37. Therefore, there is a problem that this hinders energy saving of the equipment. Relay 40
It is conceivable that the relay 40 is always turned off when the AC power supply 38 is not connected according to the sequence described above. However, in this case, the generated power generated by the rotation of the DC brushless motor 36 due to an external force such as a back wind is not effective. It is not utilized and remains abandoned. However, in order to meet the demand for further energy saving of the equipment, it is necessary to effectively use the power generated by the external force such as the headwind.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional drawbacks, and has as its object to drive an outdoor fan with a DC brushless motor, and to drive a motor without operating a DC power supply. It is an object of the present invention to provide an air conditioner that can protect a unit and can further save energy of a device.

[0008]

Accordingly, an air conditioner according to a first aspect of the present invention includes a DC power supply 1 having a smoothing capacitor 1a on an output side, a compressor motor 5 for driving the compressor, and a compressor for the compressor. Compressor motor drive unit 3 including a semiconductor switching element group for controlling motor current flowing through motor 5
A fan DC brushless motor 6 for driving an outdoor fan; a fan motor drive unit 4 including a semiconductor switching element group for controlling a motor current flowing through the fan DC brushless motor 6; A positive / negative power supply path 3a, which includes a control unit 7 for controlling the unit 3, and a switching power supply 2 for the control unit 7, and is connected to a semiconductor switching element group provided in the compressor motor driving unit 3; 3b and a positive / negative power supply path 4a, 4b connected to a semiconductor switching element group provided in the fan motor drive unit 4 on the output side of the DC power supply 1. 2
It is formed an input side thereof connected to the output side of the DC power source 1
Also, the control unit 7 determines that the DC power supply 1 is in operation.
And if it is determined that it is not operating,
Power is supplied to the compressor motor 5 without rotating it.
It is characterized by controlling the motor drive unit 3 for the compressor so that

In the air conditioner of the first aspect, the electric charge generated in the rotation of the DC brushless motor 6 due to an external force such as a back wind and stored in the smoothing capacitor 1a is transferred to the switching power supply 2a.
Is discharged. Therefore, it is possible to protect the motor driving units 3 and 4 without operating the DC power supply 1. Ma
In addition, the DC brushless motor 6
The electric power generated by the rotation can also preheat the compressor.
It becomes possible.

[0010] The air conditioner of claim 2 is characterized in that a reservoir capacitor 2a to the input terminal of the switching power supply 2.

In the air conditioner of the second aspect , the electric power generated by the rotation of the DC brushless motor 6 due to an external force such as a back wind can be stored in the storage capacitor 2a. Therefore, regardless of the capacity of the smoothing capacitor 1a,
Even when the DC current 1 is not operating, it is possible to make the control unit 7 perform necessary operations reliably.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, specific embodiments of the air conditioner of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a basic configuration relating to a motor drive of the air conditioner. In FIG. 1, reference numeral 8 denotes an AC power supply. The input side of the DC power supply 1 is connected to the AC power supply 8 via a filter 9. This DC power supply 1
Is a rectifier 1b formed by bridge-connecting diodes,
It has a relatively large-capacity smoothing capacitor 1a connected to its output side. In FIG. 1, reference numeral 5 denotes a compressor motor, and reference numeral 3 denotes a first drive circuit (compressor motor drive unit) for driving the compressor motor 5. As shown in the circuit diagram of FIG. 2, the first drive circuit 3 includes six power transistors (semiconductor switching elements) Tua, Tub, Tva, and Tv.
b, Twa, Twb to the positive power supply path (smoothing capacitor 1
a) and a negative power supply path (negative side of the smoothing capacitor 1a) 3b. Then, based on a command from the control unit 7 described later, these power transistors are turned on / off to turn on the U-phase coil C of the compressor motor 5.
It controls the current flowing through the u, V-phase coil Cv and W-phase coil Cw. Reference numeral 10 shown in FIG.

Further, in FIG. 1, reference numeral 4 denotes a second drive circuit (fan motor drive unit) for driving the DC brushless motor 6 for the outdoor fan. Although not shown, the second drive circuit 4 has substantially the same configuration as that of the first drive circuit 3, and a power transistor group provided between the positive and negative power supply paths 4a and 4b is controlled based on a command from the control unit 7. ON-OFF to control the motor current flowing through the DC brushless motor 6. In FIG. 2, reference numeral 2 denotes a switching power supply for supplying power to the control unit 7, and an input terminal thereof is provided with a storage capacitor 2a. Of the above, the positive and negative power supply paths 3a and 3b of the first drive circuit 3, the positive and negative power supply paths 4a and 4b of the second drive circuit 4, and the input side of the switching power supply 2 are:
It is connected to the output terminal of the DC power supply 1.

Next, control by the control unit (microcomputer or the like) 7 will be described. This control unit 7
When a supply of power from the switching power supply 2 is started, a routine whose flowchart is shown in FIG. 3 is executed. When the execution of this routine is started, first, in step S1, it is determined whether or not the AC power supply 8 is applied. This determination can be made, for example, by detecting the input terminal voltage of the DC power supply 1 and based on the detected voltage value Vd. Of course, other methods may be used. As described above, the control unit 7 is supplied with power from the switching power supply 2, and the input side of the switching power supply 2 is connected to the output terminal of the DC power supply 1. Therefore, in step S1, it is usually determined that the DC power supply 1 is operating, that is, the AC power supply 8 is being applied. When it is determined in step S1 that the AC power supply 8 is applied, the process proceeds to step S2. In step S2, the rotation of the compressor motor 5 and the fan DC brushless motor 6 is controlled in accordance with a command from a control device (not shown) for the entire air conditioner. This rotation control is performed by outputting a rotation speed command Cf to the first drive circuit 3 for the compressor motor 5 and for the input DC brushless motor 6 for the fan DC brushless motor 6. This is performed by outputting a rotation speed command Df to the second drive circuit 4 according to the number signal Ds. When the above control is completed, the process returns to step S1 again, and thereafter, the monitoring of the application of the AC power supply 8 and the control of the drive circuits 3 and 4 in accordance with the command of the control device are continued.

On the other hand, when it is determined in step S1 that the AC power supply 8 is not applied, the process proceeds to step S3. At this time, the control unit 7 operates even though the AC power supply 8 is not applied because the electric charge generated by the rotation of the DC brushless motor 6 due to the external force such as the back wind is generated by the capacitors 1a and 2a.
a stored in these capacitors 1a, 2a
This is because a functions as a DC power supply for the switching power supply 2. Therefore, the capacitors 1a and 2a also function as DC power supplies for the first drive circuit 3. Therefore, in step S3, the first drive circuit 3 is controlled to cause the compressor motor 5 to perform the open-phase operation. That is, since the compressor motor 5 is a three-phase motor, the U-phase coil Cu, the V-phase coil Cv, and the W-phase coil Cw normally have a U-phase waveform, a V-phase waveform, and a W-phase coil, respectively.
The compressor 5 is rotated by applying a phase waveform. However, by applying a V-phase waveform to both the V-phase coil Cv and the W-phase coil Cw, the W-phase waveform is lost. Electricity is supplied without rotating them in phase. Then, a command for performing such an open-phase operation is transmitted to the first controller.
After output to the drive circuit 3, the process returns to step S1 to monitor the application of the AC power supply 8.

In the air conditioner constructed and controlled as described above, the input side of the switching power supply 2 is connected to the output terminal of the DC power supply 1 provided with the smoothing capacitor 1a. Therefore, the DC brushless motor 6 due to an external force such as a back wind
In the switching power supply 2, at least a charge required for performing a switching operation by a switching transistor, a switching transformer, or the like can be discharged by the switching power supply 2. At this time, since the control unit 7 does not need to perform any operation, the drive circuits 3 and 4 can be protected without applying the AC power supply 8. Therefore, energy can be saved in the device.

In the above case, when a certain amount of electric charge is stored in the smoothing capacitor 1a and the control unit 7 starts operating, the compressor motor 5 performs an open-phase operation using the smoothing capacitor 1a as a DC power supply. I have. Therefore, particularly in winter or the like, the compressor can be preheated by effectively utilizing the electric power generated by the rotation of the DC brushless motor 6 due to an external force such as a headwind. Therefore, it is possible to save energy of the air conditioner excellent in quick warming.

Further, in the above, the switching power supply 2
Is also provided with a storage capacitor 2a. Therefore, regardless of the capacity of the smoothing capacitor 1a, the control section 7 can reliably perform a predetermined operation.

Although the specific embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and can be implemented with various modifications within the scope of the present invention. In the above description, the protection of the drive circuits 3 and 4 when the DC power supply 1 is stopped has been described, but the second drive circuit 4 and the DC for the outdoor fan are further protected.
A relay may be provided between the brushless motor 6 and the drive circuits 3 and 4 may be protected during the operation of the DC power supply 1 by the same control as the air conditioner described in the conventional example.

In the above description, the motor 5 for the compressor is
The V-phase waveform is applied to both the V-phase coil Cv and the W-phase coil Cw to perform the open-phase operation.
For example, the drive circuit 3 may perform an open-phase operation in which one end of the W-phase coil Cw is opened. The phase loss is not limited to the W-phase waveform as described above, but may be a U-phase waveform or a V-phase waveform.

[0022]

According to the air conditioner of the first aspect of the present invention, the motor drive unit can be protected without operating the DC power supply. Therefore, the energy saving of the device is achieved while the motor drive unit is reliably protected. It becomes possible. Also headwind
Preheats the compressor with the power generated by external forces such as
Energy saving and motor drive
Improving quick warming in winter etc. while protecting
Can also be achieved.

In the air conditioner according to the second aspect , protection of the motor drive unit and energy saving can be further ensured.

[Brief description of the drawings]

FIG. 1 is a basic configuration diagram relating to a motor drive in an embodiment of an air conditioner of the present invention.

FIG. 2 is a circuit diagram of a first drive circuit of the air conditioner.

FIG. 3 is a flowchart showing a control routine performed by a control unit of the air conditioner.

FIG. 4 is a basic configuration diagram relating to a motor drive in a conventional air conditioner.

[Explanation of symbols]

 Reference Signs List 1 DC power supply 1a Smoothing capacitor 2 Switching power supply 2a Storage capacitor 3 First drive circuit 3a Positive power supply path (+ side of smoothing capacitor) 3b Negative power supply path (-side of smoothing capacitor) 4 Second drive circuit 4a Positive power supply Path (+ side of storage capacitor) 4b Negative power supply path (− side of storage capacitor) 5 Compressor motor 6 DC brushless motor 7 Control unit (microcomputer etc.)

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-6-165566 (JP, A) JP-A-6-58600 (JP, A) JP-A-58-107092 (JP, A) JP-A-6-165600 101893 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) H02P 6/08 H02P 7/74

Claims (2)

(57) [Claims] 1. A DC power supply (1) having a smoothing capacitor (1a) on the output side, a compressor motor (5) for driving a compressor, and a motor current flowing through the compressor motor (5). Motor drive unit (3) having a semiconductor switching element group for controlling the fan, a DC brushless motor (6) for a fan for driving an outdoor fan, and a D for the fan
A motor drive unit for a fan (4) including a semiconductor switching element group for controlling a motor current flowing through the C brushless motor (6); a control unit (7) for controlling the motor drive unit for the compressor (3); A switching power supply (2) for the control unit (7), and a positive / negative power supply path (3a) (3b) connected to a semiconductor switching element group provided in the compressor motor drive unit (3). And an air conditioner in which positive and negative power supply paths (4a) and (4b) connected to a semiconductor switching element group provided in a fan motor drive section (4) are connected to an output side of the DC power supply (1). in machine, the switching power supply (2) is made its input side connected to the output side of the DC power source (1), also on
The control unit (7) operates the DC power supply (1).
If it is determined that it is not operating,
Power is supplied to the compressor motor (5) without rotating it.
An air conditioner characterized by controlling the compressor motor drive section (3) so as to be controlled . 2. The air conditioner according to claim 1, characterized in that a storage capacitor (2a) to the input terminal of the switching power supply (2).