JPH07260235A - Multi-room air conditioner and operating method therefor - Google Patents

Abstract

PURPOSE:To improve response of a flow rate change of a motor operated expansion valve to be used for an air conditioner. CONSTITUTION:Two-phase excitation and one-two phase excitation coils in which exciting currents flow to form a pulse motor for driving a motor operated expansion valve 4a provided in an outdoor unit of a multi-room air conditioner in which a plurality of indoor units 7 are connected to one outdoor unit 6 are assembled to be operated at a refrigerant flow rate stably from small to large flow rates. Accordingly, response of a flow rate change can be improved by switching a drive signal of the valve.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air conditioner, and more particularly to an electric expansion valve for an air conditioner in which one outdoor unit is connected to a plurality of indoor units.

[0002]

2. Description of the Related Art A conventional air conditioner is, for example, an actual Kaisho 48
As described in JP-A-24017, the characteristics of the opening degree and flow rate of the expansion valve are mechanically determined by the shape of the valve tip.

In other conventional air conditioners,
As described in JP-B-5-50665, when a plurality of expansion valves are provided in parallel, the focus has been on reducing the operating current of each expansion valve.

[0004]

Among the above-mentioned prior arts, the one disclosed in Japanese Utility Model Laid-Open No. 48-24017 is such that the characteristics of the opening and flow rate of the expansion valve are mechanically determined by the shape of the valve tip. Therefore, in order to incorporate the optimum characteristics for the refrigeration cycle to be used in the mechanism of the expansion valve, trial and error is required to determine the shape of the valve tip, and it is difficult to determine the shape of the expansion valve independently. Further, the one disclosed in Japanese Patent Publication No. 5-50665 does not consider the combination method of the expansion valves and the flow rate characteristic when a plurality of expansion valves are provided. Further, generally, in a combination of a large-capacity expansion valve and a small-capacity expansion valve, the expansion valve opening is equally divided from fully open to fully closed, and it is changed in steps. Therefore, as the capacity increases, the variation range of the flow rate increases, making it difficult to control the large capacity expansion valve with a small opening degree and with high accuracy.

An object of the present invention is to make it possible to adjust the flow rate of an electric expansion valve used in an air conditioner with high accuracy from a large flow rate to a small flow rate. Another object of the present invention is to provide an air conditioner capable of achieving minute flow rate adjustment with a simple structure. Another object of the present invention is to improve the characteristics of an air conditioner having a plurality of electric expansion valves in a small flow rate range.

Another object of the present invention is to allow an air conditioner equipped with an electric expansion valve to have stable operation with good operating characteristics.

[0007]

In order to achieve the above object, a single outdoor unit formed by sequentially connecting a compressor, a four-way valve, an outdoor heat exchanger, and an electric expansion valve is formed. In a multi-chamber air conditioner in which a plurality of indoor units formed by pipe-connecting an indoor heat exchanger and an expansion valve are connected, a motor for driving the electric expansion valve is a pulse motor, and the pulse motor The drive signal switching means for changing the number of exciting phases of the exciting coil is provided in the pulse motor.

Further, in a method of operating a multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit equipped with an electric expansion valve, a refrigerant discharge temperature detection of a compressor provided in the outdoor unit is detected. When the output of the means is smaller than the predetermined value, the coil of the electric motor for driving the electric expansion valve is excited by the 1-2 phase excitation, and when the output is the predetermined value or more, the two-phase excitation is performed.

Further, in a method of operating a multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit equipped with an electric expansion valve, the refrigerant of the indoor heat exchanger provided in each of the indoor units. When the flow rate obtained based on the output of the temperature detecting means for detecting the inlet temperature is smaller than a predetermined value, the coil of the electric motor for driving the electric expansion valve is excited by 1-2 phase excitation, and when the flow rate is equal to or more than the predetermined value. If so, it is a two-phase excitation.

In a method for operating a multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit equipped with an electric expansion valve, in a refrigerant discharge temperature detecting means of a compressor provided in the outdoor unit. When the output is equal to or higher than a predetermined value, the coil of the electric motor that drives the electric expansion valve is excited by two-phase excitation for a predetermined time, and then transitions to 1-2 phase excitation.

In addition, a compressor, an outdoor heat exchanger, and an electric expansion valve are sequentially connected by piping to form a single outdoor unit.
In a multi-room air conditioner in which an indoor heat exchanger and an expansion valve are connected by piping to connect a plurality of indoor units, a motor for driving the electric expansion valve is a pulse motor, and the electric expansion valve In addition, means for varying the pulse amount per unit time of this pulse motor is provided.

[0012]

The amount of drive of the drive motor for driving the expansion valve is changed to finely control the opening of the expansion valve according to the specifications of the electric expansion valve. That is, when a pulse motor is used as the drive motor, the motor rotates by an amount according to the command pulse issued from the calculation means. By the way, even with the same command pulse amount, if the exciting force of the coil for driving the motor changes, the rotation angle of the motor also changes. And this change is almost proportional to the exciting force. As shown in FIG. 2, when four exciting coils are arranged to face each other as a motor, the motor rotates if each coil is sequentially excited. At this time, it is possible to change the number of excited coils. In addition, the excitation means switching means is provided in the motor. Thereby, the rotation angle of the motor can be adjusted.

By the way, the relationship between the opening degree of the expansion valve and the flow rate is not generally linear. Normally, when the opening is small, the flow rate changes greatly with a slight change in opening, and conversely, when the opening is large, the flow rate changes little even with a large opening change.
Therefore, in order to finely control the flow rate from a large flow rate to a small flow rate, the opening change is small when the opening is small,
With a large opening, it is necessary to be able to increase the opening change,
This can be achieved by the method described above. In an air conditioner in which a plurality of indoor units are connected to one outdoor unit, if the number of expansion valves is reduced to 1, for example, the maximum capacity of the expansion valves will increase and the operating conditions of the indoor units will change. Accordingly, the flow rate range flowing through the expansion valve must be widened. Therefore, the necessity of flow rate control in a small capacity also increases. In the present invention, in this expansion valve having a large capacity, by changing the expansion valve opening characteristic with respect to the drive signal,
It is possible to provide the air conditioner with optimum flow rate characteristics. ◆ Further, if a plurality of electric expansion valves having different capacities are combined and each expansion valve is configured as described above, the flow rate can be controlled with high accuracy even when the opening is small.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. ◆ 1 for multi-room or multi-type air conditioners
A plurality of indoor units 7 are connected to one outdoor unit 6, and the outdoor unit 6 includes a compressor 1, a four-way valve 2, an outdoor heat exchanger 3a, an electric expansion valve 4a, and a gas-liquid separator 5. Has been.
On the other hand, each of the plurality of indoor units 7 is equipped with an electric expansion valve 4b and an indoor heat exchanger 3b. And these are connected by piping and comprise the refrigerating cycle. Although only two indoor units are connected to the outdoor unit 6 by piping in this figure, the number of indoor units is not limited to this.

In this multi-type air conditioner, a plurality of small-capacity indoor units 7 are connected to one large-capacity outdoor unit 6, and the indoor unit 7 is commanded by a remote controller (not shown) or the like. Each is operated individually. Then, during the cooling operation, the outdoor heat exchanger 3a of the outdoor unit 6 functions as a condenser, and at this time, the electric expansion valve 4a is used at the fully opened degree. On the other hand, during the heating operation, the outdoor heat exchanger 3a of the outdoor unit 6 functions as an evaporator, and at this time, the electric expansion valve 4a functions as an expansion means while the flow rate is adjusted with a small opening.

When the structure of the refrigeration cycle becomes large and the capacity ratios of the indoor unit 7 and the outdoor unit 6 operated by heating are significantly different, for example, one outdoor unit has a capacity of 1/10 of the outdoor unit capacity. When 10 indoor units 7 having a capacity are connected and only one indoor unit 7 is operated, it is necessary to operate the electric expansion valve 4a with a small opening. That is, as compared with an air conditioner in which only one indoor unit is connected in the related art, the minimum control width (opening width for all openings) of this electric expansion valve is an air conditioner in which N indoor units of the same capacity are connected. In the machine, it is necessary to control the control width by 1 / N. Also,
When all the indoor units 7 are cooled, the electric expansion valve 4
A large flow rate is required for a. Therefore, the electric expansion valve 4a is required to be capable of controlling a large flow rate at a fully opened opening and finely controlled at a small opening degree.

An example of the electric expansion valve used in the present invention will be described below. Outdoor heat exchanger 3a for the refrigeration cycle
The expansion valve 4a provided between the indoor unit 7 and the indoor unit 7 changes the gap between the needle and the orifice formed between the refrigerant inflow portion and the refrigerant outflow portion by moving the needle up and down in the axial direction to change the refrigerant. Adjust the flow rate. The needle is connected to the rotor via a lead screw. The rotor is driven by a drive winding from the outside of a can provided as a seal component in order to prevent the refrigerant from leaking to the outside. A pulse motor is composed of the rotor and the drive winding. Then, the rotor rotates in a predetermined direction by the number of rotations (rotation angle) according to the number of supply pulses. The rotary motion of the rotor is converted into a linear motion via the lead screw, which is transmitted to the needle as a vertical motion. The vertical movement of the needle changes the clearance between the needle and the orifice.

A circuit for driving this electric expansion valve is shown in FIG. The pulse motor PM for driving the electric expansion valve has four-phase exciting coils A, B, C and D, and is operated by switching exciting currents to the exciting coils. The pulse motor PM is provided with drive signal switching means for changing the excitation phase, and the drive signal switching means outputs a signal for instructing the coil to be excited to the drive signal output means. The drive signal switching means and the drive signal output means are usually formed by a microcomputer.

Next, a method for specifically exciting the coil will be described with reference to FIG.
And it demonstrates using FIG. The number of operating indoor units and a signal for distinguishing between heating operation and cooling operation are input from a remote controller or the like to a control device provided in the air conditioner. In other words, in a multi-room air conditioner, each room is individually turned on
/ Off and room temperature can be set. The capacity control of each indoor unit is executed by controlling the opening degree of the indoor expansion valve 4b provided on the indoor unit side by the control device. And
When the above-mentioned discrimination signal is output from the control device (not shown),
The drive signal switching means shown in FIG. 2 switches the coil excitation method to the method shown in FIG. 3 or the method shown in FIG.
That is, if the number of indoor units to be operated is small and the heating operation is performed, the drive signal switching means selects the operation method shown in FIG. For example, considering the case where each room is heated to the same degree in an air conditioner in which 10 outdoor units are connected to 1 outdoor unit, if the number of operating rooms is 3, the drive signal switching means operates. Signal with a small number (small refrigerant flow rate side)
Select. In this case, the excitation method called 1-2 phase excitation shown in FIG. 3 is applied to each excitation coil. In FIG. 3, the horizontal direction indicates the time axis, and the excited phase is A
Phase → (A phase and B phase) → B phase → (B phase and C phase) → C phase →
(C phase and D phase) → D phase → (D phase and A phase) → A phase are moved in this order, and single-phase and two-phase excitation are repeated. Therefore, the driving amount of the motor is small as compared with the two-phase excitation in which the excited phases are always two phases.

On the other hand, there are many indoor units to be operated,
Alternatively, in the case of the cooling operation, the drive signal switching means selects the method shown in FIG. The method of FIG. 4 is two-phase excitation, and (A phase and B phase) → (B phase and C phase) → (C phase and D phase)
→ (D phase and A phase) → (A phase and B phase) The excited coils move in this order, but since two phases are always excited,
Drive amount is large.

As described above, these two driving methods are combined. That is, when the opening degree of the electric expansion valve is small, a minute flow rate change is realized by 1-2 phase excitation, and when a large flow rate change is required, the driving method of the electric expansion valve is switched to change the two-phase Let's excite. FIG. 5 shows a change in the flow rate characteristic due to switching of the driving method. The first method is a standard method, and in the small opening range up to the inflection point 1 which is a predetermined switching point, the motor is driven by 1-2 phase excitation to realize a fine flow rate change. In the large opening area after the inflection point 1, the driving is performed by two-phase excitation so that a large flow rate change can be followed. It is used for normal heating operation.

The following is an application example of this driving method. Two-phase excitation is performed up to the inflection point 2 of the opening at which the required flow rate can be obtained, and 1-2 phase excitation is performed after the inflection point 2. It is a thing. This makes it possible to quickly respond to a large change in flow rate. This is convenient when the load on the indoor unit is uneven. In this case, if the point where the flow rate is larger than the inflection point 2 is in the desired operation region, the two-phase excitation is performed for a predetermined time
After that, the process proceeds to 1-2 phase excitation. This can improve the transient characteristics. In both of these examples, it is assumed that the point at which the coil excitation is switched, that is, the inflection point is stored in advance in the storage means provided in the air conditioner, but it goes without saying that it may be input by a remote controller or the like. Yes. Further, a shift of 0 point, which is likely to occur in the pulse motor, can be corrected by regularly performing zero adjustment or the like. In addition,
This switching is constantly monitored using a sensor (not shown) such as the temperature of the indoor heat exchanger provided in the indoor unit or the refrigerant temperature of the compressor, that is, the degree of superheat, and switching is performed when these values reach the above set values. Be seen.

Further, this switching method can be used depending on the operating condition of the refrigeration cycle. For example, since the outdoor heat exchanger 3a is used as a condenser during cooling operation, a large flow rate is required for the electric expansion valve 4a. Therefore, a large flow rate change characteristic is used as the driving method of the motor by the two-phase excitation method. On the other hand, during the heating operation, the outdoor heat exchanger 3a is used as an evaporator,
The electric expansion valve 4a is used as an expansion mechanism and requires fine flow rate control. Therefore, a fine flow rate change characteristic is used as a driving method by 1-2 phase excitation.

In this embodiment thus constructed, in the air conditioner system consisting of the indoor unit and the outdoor unit that are operating, the expansion valve opening change also occurs in the air conditioner system in which the number of operating units is small and the flow rate is small. It becomes smaller and transient characteristics can be improved due to flow rate fluctuations, and the system can be stabilized early. Further, in an air conditioner system in which the number of operating units is large and the flow rate is high, the expansion valve opening is large, and the required flow rate can be reached early, so the transient characteristics are improved. When the large flow rate operation is realized, if the latter method described above is used, the transient characteristic becomes more stable.

The second embodiment of the present invention will be described with reference to FIG. ◆ Two electric expansion valves 4c and 4d having different capacities are used for the outdoor unit 6. In this case, at least the small capacity electric expansion valve 4d is an electric expansion valve capable of switching between 1-2 phase excitation and 2 phase excitation. As a result, in the large capacity electric expansion valve 4c, the necessary expansion valve capacity as a whole is secured at an early stage. However, since this alone cannot sufficiently obtain a fine flow rate change at a small opening, a small capacity expansion is performed in parallel. The valve 4d is connected to secure the fine characteristics even when the opening is small. That is,
It is possible to prevent hunting of the air conditioner system due to a sudden change in the opening of the large capacity expansion valve, and to improve the transient characteristics described above. Moreover, the large-capacity electric expansion valve 4c also has 1-2 phase excitation and 2
If it is possible to switch the phase excitation, the controllability is much higher than that of the conventional expansion valve, the performance of the air conditioner is stable, and the comfort is improved.

FIG. 7 shows changes in the flow rate characteristic of the second embodiment. ◆ Small capacity electric expansion valve 4d is not suitable for a multi-type air conditioner because it has a capacity only for the flow rate shown in area 8, but large capacity expansion valve 4c is driven stepwise as shown in area 9. Then, by combining with the small-capacity electric expansion valve 4d, it becomes possible to secure the entire flow rate and to make a finer flow rate change. In this embodiment, an example in which the large-capacity expansion valve 4c is driven stepwise is shown.
As described above, if the method of changing the excitation method is used, the control accuracy at a small flow rate is improved.

[0027]

According to the present invention, even when a large-capacity electric expansion valve that can satisfy the requirements is used even when the air conditioner system of a multi-room air conditioner is fully operated, the number of phases of the pulse motor can be reduced. By switching, the responsiveness of the flow rate change of the electric expansion valve can be improved.

Further, in the present invention, in the air conditioner system having the electric expansion valves having different capacities, the electric expansion valve drive motor is provided with the phase number switching function, so that the responsiveness of the flow rate change can be improved.

[0029]

[Brief description of drawings]

FIG. 1 is a system diagram of a refrigeration cycle according to an embodiment of the present invention.

FIG. 2 is a diagram showing the configuration of a pulse motor according to an embodiment of the present invention.

FIG. 3 is a diagram showing an excited state of each phase of a pulse motor by 1-2 phase excitation.

FIG. 4 is a diagram showing an excited state of each phase of a pulse motor by two-phase excitation.

FIG. 5 is a flow rate characteristic diagram of the electric expansion valve.

FIG. 6 is a system diagram of a refrigeration cycle of another embodiment of the present invention.

FIG. 7 is a flow rate characteristic diagram of the electric expansion valve.

[Explanation of symbols]

1. ． ． Compressor, 2. ． ． Four-way valve, 3a. ． ． Outdoor heat exchanger, 3b. ． Indoor heat exchangers 4a, 4b, 4c, 4
d. ． ． Electric expansion valve, 5. ． ． Gas-liquid separator, 6. ． ． Outdoor unit, 7. ． ． Indoor unit, 8. ． ． Small capacity expansion valve flow range, 9. ． ． Large capacity expansion valve flow range, A, B, C,
D. ． ． A pulse motor coil.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Susumu Nakayama 502 Jinritsucho, Tsuchiura City, Ibaraki Prefecture Hiritsu Seisakusho Co., Ltd.

Claims (8)

[Claims] 1. An indoor heat exchanger and an expansion valve are connected to a single outdoor unit formed by sequentially connecting a compressor, a four-way valve, an outdoor heat exchanger, and an electric expansion valve. In a multi-room air conditioner connected to a plurality of indoor units formed by, a motor for driving the electric expansion valve is a pulse motor,
A multi-room air conditioner characterized in that drive signal switching means for changing the number of excitation phases of an exciting coil of the pulse motor is provided in the pulse motor. 2. The multi-room air conditioner according to claim 1, wherein the number of exciting phases is two, or the number of repeating phases is one and two. 3. The compressor is provided with a temperature detecting means for detecting a refrigerant discharge temperature or a superheat degree of the compressor, and means for activating the drive signal switching means when an output of the temperature detecting means exceeds a predetermined value. The multi-room air conditioner according to claim 1 or 2, wherein the multi-room air conditioner is provided. 4. Each of the indoor heat exchangers is provided with a temperature detecting means for detecting an indoor heat exchanger inlet refrigerant temperature, and when the flow rate obtained based on the output of each temperature detecting means exceeds a predetermined value, the driving is performed. The multi-room air conditioner according to claim 1 or 2, further comprising means for operating the signal switching means. 5. A method for operating a multi-room air conditioner comprising a plurality of indoor units connected to one outdoor unit equipped with an electrically driven expansion valve, comprising: detecting a refrigerant discharge temperature of a compressor provided in the outdoor unit. When the output of the means is smaller than a predetermined value, the coil of the electric motor for driving the electric expansion valve is excited by the 1-2 phase excitation, and when the output is the predetermined value or more, the two phase excitation is adopted. Operating method of room air conditioner. 6. A method for operating a multi-room air conditioner comprising a plurality of indoor units connected to a single outdoor unit equipped with an electric expansion valve, wherein a refrigerant for an indoor heat exchanger provided in each of the indoor units. When the flow rate obtained based on the output of the temperature detecting means for detecting the inlet temperature is smaller than a predetermined value, the coil of the electric motor for driving the electric expansion valve is excited by 1-2 phase excitation, and when the flow rate is equal to or more than the predetermined value. If so, it is a method for operating a multi-room air conditioner, which is characterized by two-phase excitation. 7. A method for operating a multi-room air conditioner comprising a plurality of indoor units connected to one outdoor unit equipped with an electrically driven expansion valve, comprising: detecting a refrigerant discharge temperature of a compressor provided in the outdoor unit. When the output of the means is equal to or greater than a predetermined value, the coil of the electric motor that drives the electric expansion valve is excited by two-phase excitation for a predetermined time,
After that, the method for operating the multi-room air conditioner is characterized by transitioning to 1-2 phase excitation. 8. An indoor heat exchanger and an expansion valve are pipe-connected to one outdoor unit formed by sequentially connecting a compressor, an outdoor heat exchanger, and an electric expansion valve to each other. In a multi-room air conditioner connected to a plurality of indoor units, the motor for driving the electric expansion valve is a pulse motor,
A multi-room air conditioner characterized in that the electric expansion valve is provided with means for varying the pulse amount per unit time of the pulse motor.