JPS5913841A - Air-conditioner - Google Patents

Abstract

PURPOSE:To control the capacity of a compressor to be able to response to the fluctuation in load in wide range, by calculating the optimum frequency to dirve an inverter, to the driving commands from a plurality of room units. CONSTITUTION:The capacity of a compressor 6 necessary to each room unit, based on the load to condition the air, obtained from room units 1a-1c such as the difference between the set temperature value and the data from room temperature sensed by room-temperature sensors 3a-3c, and the data from heat exchanger sensors 4a-4c showing the state of heat exchanging, are put into a control unit 8 as driving commands in the state of control demanding frequency data to an inverter 7. The control unit 8 determines the driving frequency to a compressor 6 from the above-mentioned drive commanding signals and the detected signals from an outdoor heat exchanger sensor 11 and a current sensor 12, and gives commands to the inverter 7. In accordance with the data demanding the maximum value amoung the data of control demanding frequency from the room units 1a-1c, and the number of operated room units, the optimum frequency is calculated based on the predetermined data.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an air conditioner that changes the rotational speed of a compressor based on an operation command from an indoor unit.

[Prior art and its problems]

An air conditioner that can operate multiple indoor units in response to one outdoor unit installed outdoors (
(hereinafter referred to as "multi air conditioner") has the advantage of being able to reduce the space required when installed outdoors.
Demand is steadily increasing in cities. However, from a functional point of view, the air conditioning load differs greatly between when one indoor unit is in operation and when a plurality of indoor units are in operation, so it is necessary to control the capacity of the compressor that constitutes the outdoor unit.

Here, the air conditioning load refers to a heating load, a cooling load, an amount of humidity control, etc. for maintaining indoor air in a required state.

Conventionally, compressors have been controlled by using a compressor with a switchable number of poles and by switching the number of poles. However, such conventional capacity control simply switches the number of poles on the compressor, so it is limited to two-stage switching of 2-pole and 4-pole, and cannot respond to certain fluctuations in air conditioning load. However, this method also had the disadvantage that it was not possible to adequately control the capacity due to changes in the number of indoor units in operation during load fluctuations due to temperature changes in each room.

Another method is to use an inverter to control the compressor and control the compression capacity by varying the output frequency of the inverter, but this method also supports operation commands from multiple indoor units like a multi-air conditioner. and set the optimum frequency as 3=1. There was no suitable air conditioner that could be used to control this inverter.

[Purpose of the invention]

The purpose of the present invention is to calculate the optimal inverter drive frequency a in response to operation commands from multiple indoor units in a multi-air conditioner using an inverter, thereby achieving compression function force control that is effective even over a wide range of load fluctuations. It is possible to provide air conditioning equipment.

[Summary of the invention]

In this invention, in order to achieve the above object, the frequency 'kl
In an air conditioner that controls the inverter by calculating and outputting an optimal frequency based on operation commands from multiple indoor units to an inverter that controls the rotation speed of the compressor by changing the rotation speed of the compressor, input the operating command based on the control request frequency data for the inverter, and calculate the optimum frequency based on data requesting a maximum value of this data and data predetermined according to the number of operating indoor units. The percentage mark is that a control unit has been installed.

The details of this invention will be described below based on examples.

[Embodiments of the invention]

FIG. 1 shows an example of a system configuration diagram of a multi-air conditioner to which the present invention is applied.

A multi-air conditioner consists of an indoor unit that is installed indoors, and in the case of this embodiment, the indoor unit la
, lb, lc and one indoor unit 2. Each indoor unit) la, lb, lc has room temperature sensors 3a, 3b, 3c and heat exchanger upper sensors 4a, 4b, 4c, respectively.
are installed, and the indoor units la, lb,
lc is operated. In addition, each indoor unit) la, lb,
LC is connected to four indoor units 5a, 5b, and 5c, and is supplied with driving power.

On the other hand, inside the outdoor unit 2, there is a compressor 6 for compressing a refrigerant such as Freon gas, and an outdoor power source 100 supplied to the compressor 6. The frequency of the compressor 60 is varied to control the rotation speed of the compressor. A control unit 8 for controlling the inverter 7 and the fz winverter on the side n are housed. In addition, the outdoor unit 2 has an outdoor heat exchanger sensor 1.
1 and a current sensor 12 are attached, and detection signals from these sensors 11 and 12 are manually inputted to the control unit 8.

Indoor units) la, lb, and lc are data indicating the difference between the temperature setting and room temperature ↓ room temperature data from sensors 3ao, t3b, and 3c, and the status of the heat exchanger from heat exchange sensors 4a, 4b, and 4c. Based on the air conditioning load, etc., the capacity of the compressor 6 necessary for the operation of the indoor unit is requested to the control unit 8 in the form of an operation command.

This operation command is controlled in the form of control request frequency data for the inverter 7! 1 unit 8.

Operation commands from each of the indoor units (la, lb, and lc) are transmitted to the control unit 8 through three sets of signal lines, three each.

The control unit 8 determines the operating frequency necessary to operate the compressor 6 from these operation command signals and the detection signal from the outdoor heat exchange sensor 11 and the cardiac flow sensor 12, and transmits this to the inverter 7. command.

In this embodiment, the frequency range controlled by the control unit 8 is from 20 to 90 I(z).

The inverter 7 drives the compressor 6 with a three-phase output of 20 to 90 Hz.

FIG. 2 is a diagram showing operation command signals sent from the indoor units la, lb, and lc to the control unit 8.

The operation command signal is composed of 11 bits from 0 to 10 as one set of data, and is transferred using the positive half cycle of the power supply frequency.

Each bit has the following meaning depending on whether the positive half cycle is 0'' or 1#. Section A indicating 0 bit is a bit indicating the start of data and is called a start bit. This section A always shows 0# at the start. Section B indicating the 1st bit indicates air conditioning data, and when it is "0" it indicates cooling, and when it is l it indicates heating. In section C indicating 2 to 504 bits, the frequency from 0 to 90 Hz is 16
Frequency data bits assigned as a combination of digital signals in common.

Frequency allocation is performed as shown in Table 1.

Table 1 The section indicating the 6th bit is called a release bit, and when the detection signals of the indoor heat exchanger sensors 4a, 4b, and 4c reach a predetermined value, a signal of K"0" is output, and the data of section C is This bit is used to perform control to lower the operating frequency with priority.

Also, the interval E indicating 7 to 1004 bits is always 1 s, and is a bit used to make it easier for the control unit 8 to determine the position of the start bit in the interval, and is called a stop bit.

Since the operation command signal is a digital signal composed of serial data including the control request frequency data (section C) in this way, there is an advantage that a large number of signal lines between the indoor unit and the outdoor unit are not required.

Next, the operation of this multi air conditioner will be explained.

The data for section B shown in Fig. 2 is for indoor units la and l.
It is determined by inputting operation switches b and lc (not shown).

In other words, cooling switch 1 is set to '0'', heating switch 1 is set to '0''
, respectively, and the refrigeration cycle of the outdoor unit 2 is switched to the cooling or heating cycle.

All data for section C is determined by the temperature inside the school and the temperature of the heat exchanger during operation.

Figure 3 is a diagram showing a state in which the refrigeration cycle is divided into multiple zones according to the difference between the room temperature and the temperature set value.The fluctuation range of the difference between 0 room temperature and the temperature set value is as shown in Figure 3. The room temperature is divided into multiple zones depending on whether the room temperature is on a downward slope or on an upward slope.

The area in the case of a downward slope is shown as X1, and the area in the case of an upward slope is shown as Y. Here, a case will be described in which the difference between the room temperature and the temperature set value in region X in the case of a downward slope is divided into a plurality of zones and a control request frequency is assigned to each zone.

For example, in a zone where the room temperature is 2°5 or more higher than the temperature set value, the control required frequency data for that indoor unit is 90.
Hz and below 2.0t ~ 2.5
80 Hz between t, ----, -1,0t! In the following, the frequency is assigned to 0Hz (stop).

Table 2 shows the relationship between these temperature ranges and control required frequencies.

Table 2 This shows that the difference between room temperature and temperature set value is, for example, 1.0υ~1
．． If it is between 5υ, it means that the indoor unit gives an operation command to the control unit 8 to output a 60Hz frequency setting signal to the inverter 7.

Such control request frequency data is for three indoor units)
The control unit 8 inputs these three data and calculates the optimum frequency using the following procedure.

First, among the control request frequency data sent from the indoor units la, Ib, and lc, the data that requests the output of the highest frequency is validated, and the data is determined in advance according to this data and the number of operating indoor units. The optimal frequency 'ff:q is output based on the data obtained.

'MA!' data to determine the maximum operating frequency mentioned above.
Table 3 shows an example of the relationship with data predetermined according to the number of operating indoor units.

As shown in Table 3, depending on the number of operating indoor units, the maximum wave number is determined to be 90 Hz for three indoor units, 70 Hz for two indoor units, and 50 Hz for one indoor unit, and the required capacity of the compressor 6 is controlled.

For example, the maximum control request frequency from the indoor unit is 80.
Considering the case of Hz, if the number of indoor units in operation is one, as is clear from Table 3, the control/required frequency of 80Hz is not adopted and the frequency is 50Hz.
The compressor 6 will operate accordingly.

Similarly, when the number of indoor units in operation is two, they are operated according to 70 Hl, and only when the number of indoor units in operation is three, the maximum control required frequency of 80 Hl is adopted.

By performing such control, overload control of the refrigeration cycle is also performed.

The control unit 8 is mainly based on a microcomputer, and its control specifications are compatible with the microcomputer program, so it is easy to store and change data predetermined according to the number of operating indoor units as shown in Table 3. [Effects of the Invention] As explained in detail based on the embodiments above, the present invention is equipped with a control unit mainly based on a microcomputer. The optimum operating frequency of the compression rack is controlled based on the data requested for up to one shift out of the control dormitory frequency data sent from the unit and data predetermined according to the number of operating indoor units. Because of the structure, it is possible to easily eliminate inconveniences associated with light and heavy air conditioning loads, and also has the advantage that overload control of the refrigeration cycle can be performed.

[Brief explanation of drawings]

Fig. 1 is a system configuration diagram showing an example of an air conditioner to which the present invention is applied, Fig. 2 is a diagram showing the data structure of an operation control command, and Fig. 3 is a diagram showing a refrigeration cycle divided into multiple zones. It is. la, lb, lc...indoor unit, 2...outdoor unit, 6...compressor, 7...inverter, 8...
·Controller unit. Applicant's agent Kiyohisa Inomata 1 Utsuriichi ------------J Figure 2 Figure 3-x -m--4--Y -□

Claims (1)

[Claims] 1. Calculates and outputs an optimum frequency based on operation commands from a plurality of indoor units for an inverter that controls the rotational speed of a compressor by varying the frequency, and controls the inverter. In the air conditioner, the operation command based on the air conditioning load is input as control request frequency data for the inverter, data that requests the maximum value of this data, and data predetermined according to the number of operating indoor units. An air conditioner comprising: a control unit that calculates the optimum frequency based on the above. 2. The air conditioner according to claim 1, wherein the operation command is a digital control signal composed of serial data including control request frequency data.