JP2604258B2 - Inverter air conditioner - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter air conditioner, and more particularly, to an inverter air conditioner connected in parallel to an AC power supply via a breaker having a predetermined capacity.

[Prior art] In general, a converter, an inverter, and the like are configured by appropriately combining diodes, capacitors, transistors, and the like, and a DC voltage obtained by rectifying commercial power is converted into a pulse having a predetermined frequency and supplied to a compressor. Inverter air conditioners that control the operating frequency of the compressor while detecting the operating current of the compressor are well known.

Conventionally, in an inverter air conditioner, an upper limit value of an operation current can be set according to the capacity of a power supply breaker. When two inverter air conditioners are installed, the upper limit of the operating current of each inverter air conditioner is set so as not to exceed the breaker capacity. For example, if the breaker capacity is 30A and the inverter air conditioner can switch the upper limit to 15 / 20A, the operating current of both inverters is set to 15A.

By setting the upper limit value of the operating current as described above, the two inverter air conditioners do not exceed the current capacity of the breaker even if they are fully operated within the set value, so that they can be operated smoothly.

[Problems to be Solved by the Invention] However, even if the operating current of one inverter air conditioner drops to 10A and the other inverter air conditioner wants to operate at 15A or more, the upper limit value of the inverter air conditioner is set to 15A. Therefore, despite the ability to operate at a current of 20A, it is not possible to operate at a current of 15A or more. That is, even if it is desired to further increase the air conditioning capacity, there is a disadvantage that the capacity is limited.

Therefore, a main object of the present invention is to provide an inverter air conditioner capable of maximizing its performance even when a plurality of breakers having a predetermined capacity are connected in parallel.

Means for Solving the Problems An inverter air conditioner according to the present invention is an inverter air conditioner that is connected in parallel to an AC power supply via a breaker having a predetermined capacity and has a temperature for detecting an indoor temperature. Detecting means, temperature setting means for setting the room temperature to a desired value, cooling means capable of controlling the cooling capacity for cooling the room, and the room temperature detected by the temperature detecting means are set by the temperature setting means. Control means for controlling the cooling capacity of the cooling means to match the room temperature,
The current detection means for detecting the current flowing from the AC power supply to the cooling means, and the current detection means of each of the other inverter air conditioners connected in parallel are connected by a signal line, and the capacity of the breaker and the signal line It is provided with current limiting means for obtaining a difference from the sum of the detection values of the given current detecting means of each of the other inverter air conditioners and limiting the current flowing from the AC power supply to the cooling means within the range of the difference. is there.

[Operation of the Invention] In the inverter air conditioner according to the present invention, the current detection means detects its own current consumption, while the current limiting means connected to the current detection means of each of the other inverter air conditioners via signal lines reduces the capacity of the breaker. The difference from the sum of the current consumption of each of the other inverter air conditioners is determined, and the current consumption of the inverter air conditioner is limited within the range of the difference. Therefore, it is possible to use a larger current than before, where the upper limit of the current consumption is uniformly limited to the value obtained by dividing the breaker capacity by the number of parallel operation units, and the capacity of the inverter air conditioner is maximized. .

Examples Examples of the present invention will be described below with reference to the drawings.

FIG. 1 is a circuit diagram showing one embodiment of the present invention. Referring to FIG. 1, power supply source 1 supplies 100 V AC, 30 A, single-phase commercial power to breaker 2. The power supplied to the breaker 2 is supplied to the first inverter air conditioner 4 and the second inverter air conditioner 5 via the power line 3. The above AC100V
Alternatively, AC200 or a three-phase power supply may be used.

The first inverter air conditioner 4 and the second inverter air conditioner 5 have the same configuration, and the upper limit of the operating current is 15A or 20A.
Can be switched over.

The first inverter air conditioner 4 has an indoor unit 6 and an outdoor unit 7. The indoor unit 6 switches the indoor control unit 8, the operation / stop switch 9, and the upper limit of the operation current to one of 15/20 A. Switch 10, room temperature setting device 11 for setting room temperature, thermistor 12 for detecting room temperature, fan motor 13
Etc. The indoor side control circuit 8 performs operation / stop control by turning on / off the operation / stop switch 9.
In addition, the operating current is switched to 15A or 20A in response to the switching operation signal of the changeover switch 10. The changeover switch 10 is automatically switched by the indoor control circuit 8. Also,
The indoor side control circuit 8 responds to the room temperature detection signal of the thermistor 12 to control the rotation speed of the compressor 16 of the outdoor unit 7 to approach the room temperature set by the temperature setting unit 11. The control of the rotation speed is performed by designating the frequency. The frequency designation signal, the on / off signal, and the upper limit value setting signal are provided to the outdoor unit 7 via the signal line 14.

The outdoor device 7 includes an outdoor control circuit 15, a compressor drive motor 16, a fan motor 17, a current transformer 18, and the like.

The outdoor control circuit 15 rectifies 100 V AC from the power supply source 1, converts the rectified current into a three-phase AC current having a frequency designated by the indoor control device 8, and supplies the three-phase AC current to the compressor drive motor 16 and the fan motor 17. give. Note that the compressor drive motor 16 may be a single phase. In this case, the outdoor control circuit 15 generates single-phase AC power. The current transformer 18 monitors the power supply current,
The outdoor control circuit 15 sends this current data together with the upper limit setting current data (15/20 A) to the second inverter air conditioner 5 through the signal line 19. The outdoor control circuit
Reference numeral 15 transfers the operation current data upper limit setting current data from the second inverter air conditioner 5 to the indoor side control circuit 8 via the signal line 14.

The second inverter air conditioner 5 has an indoor device 21 and an outdoor device 22 similarly to the first inverter air conditioner 4. The indoor device 21 includes an indoor control device 23, an operation / stop switch 24, and a changeover switch 25 for switching operation current. , A room temperature setter 26, a thermistor 27, a fan motor 28, and the like. The indoor device 21 and the outdoor device 22 are connected by a signal line 29.

The outdoor device 22 includes an outdoor control circuit 30, a compressor drive motor 31, a fan motor 32, a current transformer 33, and the like. Since the second inverter air conditioner 5 has the same configuration as the first inverter air conditioner 4, the description of each unit such as the indoor control circuit 23 is omitted.

FIG. 2 is a timing chart for explaining the operation of the control device for the inverter air conditioner shown in FIG.
FIG. 2 (a) shows the relationship between the operating current of the first inverter air conditioner 4 and time, and FIG. 2 (b) shows the relationship between the operating current of the second inverter air conditioner 5 and time.

First, when operating the first inverter air conditioner 4 and the second inverter air conditioner 5, the operation / stop switch 9,
Turn on 24 (T0 in the figure). The indoor controllers 8 and 23 automatically set the changeover switches 10 and 25 to the 15A side in response to the turning on of the switches 9 and 24.

Next, according to the difference between the temperature set by the room temperature setting units 11 and 26 and the temperature detected from the thermistors 12 and 27, the indoor control circuit 8 drives the compressor drive motors 16 and 31 at a predetermined rotation speed. Supply current of frequency to rotate.

The compressor is driven by this current supply, and the supply current from the power supply source 1 increases. The power supply current at this time is detected by the current transformers 18 and 33, and the current data is sent to the outdoor control circuits 15 and 30 via the signal line 19. Also, a set current of 15A is sent. Data relating to these operating currents is transferred to the indoor side control circuits 8 and 23 via the signal lines 14 and 29.

Next, at time T1 in FIG. 2, the operating current of the first inverter air conditioner 4 decreases to 10A. That is, when the room temperature data detected by the thermistor 12 provided in the indoor unit 6 approaches or coincides with the set value set by the room temperature setter 11, the frequency is controlled so as to be lowered, and the first inverter air conditioner is controlled. 4, the operating current decreases.

On the other hand, when the room temperature data detected by the thermistor 12 provided in the indoor device 21 is far from the set temperature set by the room temperature setting device 26, the indoor control circuit 23 of the second inverter air conditioner 5 The operating current margin is calculated based on the operating current 10A of the first inverter air conditioner 4 and the upper limit 15A, and the operating frequency corresponding to increasing the operating current by 5A (changing from 15A to 20A) is designated. Outdoor control circuit
The 30 generates an AC voltage having a designated frequency and supplies the AC voltage to the compressor drive motor 31. As a result, the second inverter air conditioner 5 can perform an operation that fully demonstrates its capability.

Next, when the first inverter air conditioner 4 needs an operation current of 15 A at the time T2, a signal is sent to the second inverter air conditioner 5 and the second inverter air conditioner 5 switches the changeover switch 25 to 15 A. After that, the motor is operated with the operating current of 15A.

Next, at time T3, the room temperature of the indoor device 21 increases,
When the inverter air conditioner 5 is operated at 10A and the first inverter air conditioner 4 requires an operation current of 20A,
Set current 15A, operating current 10A of the second inverter air conditioner 5
Calculate the margin of the operating current based on the above, and operate with the increased current of 5A at 20A.

As described above, based on the operating current and the set current of the other inverter air conditioner, a margin for the operating current is calculated,
By operating with the current increased by this margin, the total operating current of the inverter air conditioner can be fully operated within the capacity range of the breaker 2.

In the above embodiment, the case of two inverter air conditioners has been described. However, an inverter air conditioner may be added in accordance with the capacity of the breaker 2 and the outdoor control circuits of each inverter air conditioner may be connected to each other by a signal line. . By doing so, more inverter air conditioners can be fully operated within the capacity of the breaker.

In the above embodiment, the first inverter air conditioner and the second
Although they have the same configuration as the inverter air conditioner, they may have different capabilities.

[Effects of the Invention] As described above, according to the present invention, each inverter air conditioner detects its own current consumption and other current consumption, obtains the current that can be used by itself based on the detection result, and sets the current within the range of the current. Since the operation is performed, the maximum current is used within the range of the breaker capacity, and the capacity of each inverter is maximized.

In addition, since a difference between the capacity of the breaker and the total current consumption of each of the other inverter air conditioners operated in parallel is calculated, and means for controlling the operating current within the range of the difference are provided in each inverter air conditioner, In the installation work and the extension work, the inverter air conditioners need only be provided and the inverter air conditioners need only be connected by signal lines, so that the installation work and the expansion work can be performed extremely easily.

Further, even if one of the plurality of inverter air conditioners fails, the other inverter air conditioners do not become unusable. Therefore, a faulty inverter air conditioner can be easily specified, and its repair can be performed without stopping other inverter air conditioners.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing a control device for an inverter air conditioner according to the present invention, and FIG. 2 is a timing chart of the control device for an inverter air conditioner shown in FIG. In the figure, 2 is a breaker, 4 is a first inverter air conditioner, 5 is a second inverter air conditioner, 8 and 23 are indoor side control circuits, 10 and 25 are changeover switches, 15 and 30 are outdoor side control circuits, and 16 and 31 are A compressor drive motor, 18 and 32 are current transformers, and 19 is a signal line.

Claims (1)

(57) [Claims] 1. An inverter air conditioner connected in parallel to an AC power supply via a breaker having a predetermined capacity, a temperature detecting means for detecting an indoor temperature, and setting the indoor temperature to a desired value. Temperature setting means for controlling the cooling capacity for cooling the room, the cooling means capable of controlling the cooling capacity, and the cooling so that the room temperature detected by the temperature detecting means matches the room temperature set by the temperature setting means. Control means for controlling the cooling capacity of the means; current detection means for detecting a current flowing from the AC power supply to the cooling means; and a current line connected to the current detection means of each of the other inverter air conditioners connected in parallel. And the capacity of the breaker,
The difference from the sum of the detection values of the current detection means of each of the other inverter air conditioners provided via the signal line is obtained, and the current flowing from the AC power supply to the cooling means is limited within the range of the difference. An inverter air conditioner including current limiting means.