JPS6249144A - Multiple-room type air conditioner - Google Patents

Abstract

PURPOSE:To enable effectively controlling the capacity of a compressor by giving to the compresso a command as to a totalized value of a compressor commanded rotational speeds based on a set room temperature commanded from respective indoor units and a current room temperature. CONSTITUTION:The rotational speeds N1, N2 and N3 are commanded from respective units 1, 2 and 3 as required rotational speed signals based on the difference between the set temperature of a temperature adjustor and an actual room temperature. When a required rotational speed signal N1 of the indoor unit 1 and a required rotational speed signal N3 of the indoor unit 3 are supplied to a control part 4, said part 4 judges that two units are in operation and calculates the total sum of the required rotational signals N1 and N3 thereby to determine the compressor rotational speed command. By this determined compressore rotational speed command, an inverter 5 is controlled to operate the compressor 6. However, the control due to the total rotational speed is set such that the compressor 6 stops in a maximum rotational speed range, whereby a wasteless capacity control of the compressor is possible and further evils accompanied by the overload operation or the over capacity operation can be removed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention is applied to a multi-room air conditioner that changes the rotational speed of a compressor based on an operation command from an indoor two-way generator.

[Background of the invention]

As a rotation speed control method for a multi-room air conditioner that can change the pressure f1 machine rotation speed using an inverter, the command rotation speed of the operating indoor unit is disclosed in Japanese Patent Application Laid-Open No. 59-131843. There is a method of taking the largest command rotation speed among them as valid data and commanding the command rotation speed to the compressor according to a relationship predetermined based on the number of operating indoor units. However, although this method is superior in terms of power consumption, the upper limit of the capacity is low due to the specified formula, especially when a large capacity is required for single-room operation. There was a point where I was being held back.

[Purpose of the invention]

The purpose of the present invention is to provide a multi-room air conditioner using an inverter, which takes in all operating commands from multiple indoor units as data and is effective under a wide range of operating conditions from the start of cooling/heating operation to steady operation. Capacity of compressor #i! The purpose of the present invention is to provide an air conditioner of various types capable of I#.

[Summary of the invention]

In order to achieve the above object, this invention gives a rotation speed command to the compressor based on the sum of the command rotation speeds of each indoor unit during steady j overturning to obtain an appropriate capacity and to obtain the maximum capacity. At the start of cooling/heating operation, the refrigeration cycle and compressor are held at the maximum allowable rotation speed for a certain period of time depending on the number of units in operation, making effective use of the compressor's capacity, and further reducing the outside temperature during cooling. When the outside temperature is high during heating, the inverter detects the outside temperature and turns on the inverter.
This is to shift down the Jff order rotation '11 to the compressor by a certain value.

[Embodiments of the invention]

The details of this invention will be explained below using an example in which there are three indoor units.

FIG. 1 shows an embodiment of a multi-room air conditioner to which the present invention is applied. In FIG. 1, 1 is a first indoor unit, 2 is a second indoor unit, 1-13 is a third indoor unit, and 4 is a rotational speed command N1. a control unit that controls the signals of N2 and Ns;
5 is an inverter that gives a rotation speed command to the compressor, and 6 is the compressor. N4 is the number of indoor units in operation at that time,
This is the commanded rotation speed that is determined by a control unit having a microcomputer based on the operating state and the like, and is slid into the inverter.

Number of rotations commanded from each indoor unit Nl, N2°N3
A command rotation speed signal is issued as the required rotation speed based on the difference between the set temperature of the temperature controller and the actual room temperature.

Table 1 shows an example of the heating operation. Note that this may be based on the difference between the intake air temperature and the discharge air temperature of the indoor unit.

Table 1 Such a rotation speed command from each indoor unit requests the cooling/heating capacity required by that indoor unit. Therefore, the control section 4 receives signals from each indoor unit and inverts the inverter 5 as shown in the flowchart in Fig. 2.
The compressor rotational speed command to be given to the compressor is determined by calculating the sum of the required rotational speed signals N1 to N5 of the respective indoor units that are in T rotation at that time. For example, the required rotation speed signal N1 of indoor unit l and the required rotation speed signal N3 of indoor unit 3
When this is input to the control unit 1, it is determined that 52 units are in operation, and the sum of the required rotation speed signals N1 and N3 is calculated to determine the compressor rotation speed command. The inverter 5 is controlled based on this determined compressor rotation speed command to operate the compressor. The compressor rotation speed command is determined by calculating the sum of required rotation speed signals N1 to N5 of the indoor units being operated. The reason is that the cooling/heating capacity is proportional to the rotation speed of the compressor. But pressure M? The maximum rotational speed of 1if has its own limit, and if the maximum rotational speed is 10,000 rotations, the control based on the total rotational speed will be limited to a total of 1o, oooN rotation. Set. Note that the sum of the rotational speed commands from each indoor unit reaches the maximum rotational speed limit in practical terms at the start of cooling/heating operation, so at this time the control unit is configured to operate at the maximum rotational speed for a limited period of time. You can roll with control 1. This limit rotational speed is also determined by the operating conditions of the refrigeration cycle.For example, there is a limit on the indoor unit cabinet frosting due to excessive cooling when only one room is operated during cooling operation,
Or, there are restrictions due to the temperature rise of the winding due to superheat 1 of the compressor when operating in all rooms, restrictions due to the prevention of damage to the machine due to the increase in discharge pressure when only one room is operated during heating operation, and also restrictions due to heating operation. The limit rotation speed is determined based on conditions such as restrictions such as preventing frost formation on the outdoor heat exchanger due to a drop in suction pressure during full-room operation, and the required capacity. After a certain period of time has elapsed, control is performed to reduce the rotational speed to an economical rotational speed that is one step lower than that of t and is allowable for reliability and longevity. Table 2 shows an example.

Table 2 Note that the above-mentioned fixed time is not mandatory, and if the total number of rotations required by each indoor unit within that time is less than this, the number of rotations will be reduced accordingly. Furthermore, the method of incorporating the maximum value of the operating command rotation speed of each indoor unit given in the cited publication as data, only the one room that was operated later was close to the maximum possible rotation speed of the compressor and compressor. In some cases, even if the load in the other room that was operating has become lighter, the rotation speed of the compressor will be close to the maximum rotation speed. Since it is based on the sum of the required rotational speed commands, it has the advantage that the rotational speed is not wasted. Therefore, energy efficiency also increases. Furthermore, when the outside temperature is low during cooling operation, the compressor does not need to rotate at such a high speed.
．． 000 rotations, each indoor unit common electric low rotation speed 2
,000 rotations, and if there are three indoor units, the total rotation speed will be 2,000 x 3 = 6,000 rotations, and even if the compressor rotation speed below this is acceptable, Uncontrollable. In such a case, 1
For example, when the outside temperature is 21°C or less and the rotation speed is
Table 2 shows an example of reducing the rotational speed command given to the inverter by a certain value based on the sensing action of the outside temperature thermistor 4a installed in the inverter and the number of inverters in operation.

Table 2 When the outside temperature is high during heating operation, the outside temperature sensing thermistor 4a is similarly disturbed and the rotational speed is decreased by 1 shift. Examples are shown in Table 3.

Table 3 Note that this embodiment shows an example of downshifting at a certain rate, but instead of this, the rotation speed command of the unit that indicates the M a x rotation speed of the indoor unit being operated is followed. The method can also be considered as an application.

〔Effect of the invention〕

According to the present invention, the rotation speed of the compressor can be determined so as to exhibit the total capacity required by each indoor unit, so it is possible to control the capacity without waste, and also to prevent overload operation, can also eliminate the negative effects of over-capacity operation,
It has the advantage that stable and highly reliable operation control is possible. Furthermore, more economical operation is possible by shifting down the sliding rotation speed to the inverter by a certain value using an outside temperature thermistor as a compensation when the load on the cooling/heating V, 〒 is light.

[Brief explanation of the drawing]

FIG. 1 is a system configuration diagram showing an embodiment of an air conditioner to which the present invention is applied. FIG. 2 is a flowchart 1 of the rotational speed control method showing one embodiment. I...First indoor unit, 2...Second indoor unit, 3'-Third indoor unit, 4...Control unit, 5...
...Inverter, 6...Compressor.

Claims (1)

[Claims] 1. In a multi-room air conditioner that has an inverter that controls the rotational speed of the compressor and that connects a plurality of indoor units, the set room temperature and the current room temperature that are commanded from each indoor unit. A multi-room air conditioner characterized in that a total value of compressor command rotation speeds based on the difference between the two is commanded to the compressor. 2. The compressor command rotation speed is the maximum rotation speed allowed for the refrigeration cycle and compressor for a certain period of time after the operation switch is first turned on, and after a certain period of time, the maximum rotation speed is determined by the number of indoor units in operation. A multi-room air conditioner according to claim 1.