JPH0436314B2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) This invention relates to an air conditioner, and includes:
This invention relates to an air conditioner with improved heating speed.

(Prior art) Adding an electric heater to each indoor unit in order to supplement the heating capacity of a heat pump type air conditioner is disclosed in, for example, Japanese Patent Publication No. 57-36501 and Japanese Patent Application Laid-Open No. 57-2946. It is known as described in . In each of the above air conditioners, when the current supplied to the compressor increases, the electricity to the electric heater is stopped, and when the total current value supplied to the air conditioner falls below a certain value, the breaker Control is being carried out to keep it below the capacity. The reason why the electricity supply to the electric heater is stopped with priority over the compressor is that the energy efficiency of the electric heater is lower than that of the compressor.

(Problems to be Solved by the Invention) By the way, in an air conditioner that performs the above-mentioned control, it is possible to improve the energy efficiency in a steady operating state, but on the other hand, it is possible to improve the energy efficiency during startup, that is, from startup. It has a drawback that it lacks quick warming up until it shifts to steady operation. This is because the heating capacity of heat pump air conditioners is not sufficient during start-up operation, and the heating load is large during start-up operation.In addition, the compressor requires a large amount of current, so electric heaters with excellent heating speed This is because it has to be stopped.

This invention was made in order to solve the above-mentioned conventional drawbacks, and its purpose is to provide an air conditioner that has excellent heating speed at startup, etc., and is capable of fine-grained operation control. It is about providing.

(Means for solving the problem) Therefore, in the air conditioner of the present invention, the first
As shown in the figure, an outdoor unit X having a compressor 1 with variable compression capacity and a plurality of indoor units A...
The air conditioner has a refrigerant circuit 19 for heat pump heating that increases or decreases the compression capacity of the compressor 1 according to the load detected indoors, and an electric heater 16 arranged in each indoor unit A. integrated current detection means 29, 32 for detecting the integrated current supplied to the air conditioner;
Compressor input current detection means 30, 36 for detecting the current supplied to the compressor 1; priority determination means 42 for determining the priority of each indoor unit A; and the indoor side detection means 42 for determining the priority of each indoor unit A. Even if the compression capacity increased according to the load reaches the upper limit capacity, the capacity of the compressor 1 is reduced so that the total current is below a certain value under the condition that there is still a request to increase the compression capacity due to the indoor side detected load. The above electric heater 16
and heater operation control means 43 for operating the heaters according to the priority order.

(Function) As mentioned above, when starting up, etc., the electric heater 1
6, the heating speed is excellent. In addition, the electric heater 16
Since preferential energization is performed depending on the indoor situation, fine-grained operation control can be performed depending on the indoor situation. Moreover, since the total current is maintained below a certain value by reducing the current supplied to the compressor 1 according to the amount of current supplied to the electric heater 16, the total current supplied to the air conditioner is kept at a predetermined value. It will never exceed its capacity.

(Embodiments) Next, specific embodiments of the air conditioner of the present invention will be described in detail with reference to the drawings.

First, Fig. 2 shows the refrigerant piping system of a multi-type air conditioner equipped with four indoor units.
C and D indicate the first to fourth indoor units, respectively. The outdoor unit X has an inverter 1a
a compressor 1 whose capacity is controlled by a compressor 1, a four-way switching valve 2 which switches as shown by the solid line in the figure during cooling operation and as shown by the broken line in the figure during heating operation, and an outdoor heat exchanger 3 having a blower fan 3a. A first motor-operated valve 4, which is fully opened during cooling operation and controls the degree of superheating of the refrigerant during heating operation, and a liquid receiver 5, are provided corresponding to each of the above-mentioned indoor units A...D, and are fully opened during cooling operation. It has a total of four second electric valves 6 to 9 that control the degree of superheating of the refrigerant and control the degree of subcooling of the refrigerant during heating operation, and an accumulator 10, and each device 1 to 10 has The refrigerant pipes 11 are connected to each other so that the refrigerant can flow therethrough. In addition, each indoor unit A~
D each has an indoor heat exchanger 15 and an electric heater 16 that serves as an auxiliary heat source during heating operation.

The four indoor units A to D have refrigerant pipes 18...
... to form a refrigerant circulation circuit 19. That is, during cooling operation, by circulating the refrigerant as shown by the solid line arrows in the figure, the heat absorbed from the room by each indoor heat exchanger 15 is released into the outside air from the outdoor heat exchanger 3, which is repeated to cool each room. On the other hand, during heating operation, the refrigerant is circulated as shown by the broken line arrow in the figure, thereby reversing the heat reception, and when the electric heater 16 is activated, it heats each room with its radiated heat. It has been done so that it can be done. In the figure, 20 is a capillary reach tube, and by returning the refrigerant in the liquid receiver 5 to the accumulator 10 by this tube 20, the evaporation temperature during the refrigeration cycle is detected at the exit of the capillary reach tube 20. It's summery. Further, 22 is a high pressure switch that detects the discharge pressure of the refrigerant, 23 is a liquid shutoff valve,
24 is a gas shutoff valve.

Next, the operation control mechanism of the air conditioner will be explained based on FIG. 3. As shown in the diagram, the outdoor unit
has an outdoor control device 25 and an inverter control device 26, and each indoor unit A to D
have indoor control devices 27...27, respectively. Each indoor control device 26 outputs a temperature difference signal (hereinafter referred to as ΔT signal) corresponding to the difference between the temperature detected by the indoor thermometer and the set temperature, and a heater operation request signal (hereinafter referred to as ΔT signal) indicating the user's desire to use the electric heater 16. A heater ON request signal) is input to the outdoor control device 25, while a heater operation signal (heater ON signal) is input from the outdoor control device 25 to each indoor control device 27, and a heater ON signal is input to the inverter control device 26. A frequency command signal is output. Furthermore, the outdoor control device 25 receives a priority determination signal from a select switch 28 serving as a priority setting means for manually changing the operational priority of each of the indoor units A to D from the standard priority; The first integrated current detection means for detecting the integrated current supplied to the air conditioner.
The total current signal from the transformer 29 and the compressor 1
an input current signal from the second transformer 30 as a compressor input current detection means for detecting the input current supplied to the breaker, and a breaker selection switch 31 for setting the maximum value of the total current to a desired value. A capacitance selection signal is respectively input.

That is, the breaker selection switch 31 selects the breaker capacity as a reference for current comparison so that the air conditioner can be controlled within the capacity of the breaker installed in the power line connected to the air conditioner.
The IB value can be selected. Examples of IB include values such as 30A, 40A, 50A, etc. If we consider the case where the maximum allowable total current is, for example, an air conditioner of 50A, the value of the breaker installed in the house is as small as 30A. If the breaker capacity is smaller than 50A, a conventional 50A air conditioner cannot be used, but if the breaker capacity IB can be arbitrarily selected as a comparison standard, it is possible to use a 50A air conditioner in a house equipped with a breaker smaller than 50A. can also be handled. This is even more effective in the case of multi-type air conditioners.In multi-type air conditioners, it is rare for all indoor units to be operated at the same time, so even if the breaker value is slightly smaller, priority is given to the operation of the indoor units. This is because even one type of air conditioner can be used in houses where various types of circuit breakers are installed without interfering with air conditioning operation through controls such as turning on the switch. Also, from the breaker equipment side, for example, it is possible to install breakers according to the floor area of each unit in an apartment complex, which reduces the capacity of the power receiving equipment and reduces the costs associated with power supply equipment. Even if an air conditioner has a maximum total current of 50A for each resident, it can be supplied to a residence with a small breaker, contributing to comfortable air conditioning. Furthermore, even when relocating an air conditioner, it is possible to relocate the equipment even if the value of the breaker at the new location is small, which is very effective. The total current signal from the first transformer 29 is transmitted to the total current detection circuit 3.
2, the current is compared with the breaker capacity in the current comparison circuit 33, and if the breaker capacity is exceeded, the frequency control circuit 3 is transferred from the general current drooping circuit 34.
A total current droop command is output to 5. From the frequency control circuit 35 to the inverter control circuit 26
Then, a frequency command signal lower than the current frequency is output to lower the total current. Note that this frequency command signal is controlled so as to decrease the frequency by a constant frequency at regular intervals. Also, the second
The input current signal from the transformer 30 passes through the input current detection circuit 36 and is compared with a reference current in the current comparison circuit 37, and the input current drooping circuit 38 outputs a frequency signal to prevent the input current of the inverter 1a from exceeding the upper limit value. An input droop command is output to the control circuit 25. The input current droop in this case is also carried out in the same manner as the above-mentioned total current droop. On the other hand, based on the ΔT signals output from each indoor control device 27, the frequency calculation circuit 39 calculates the sum of the ΔT signals for each room, that is, ΣΔT
In addition to calculating the signal, a frequency increase or decrease command signal is output to the frequency control circuit 35 based on the ΣΔT signal to control the frequency of the inverter 1a. Further, the frequency increase command signal and the frequency decrease command signal from the frequency calculation circuit 39 are respectively outputted to the heater ON condition determination circuit 40. The arrival signal and a signal indicating that the input current from the input current drooping circuit 38 is drooping are respectively input. When this heater ON condition determination circuit 40 outputs a signal indicating that the heater should be turned ON or OFF in accordance with the procedure described later, the current comparison circuit 33 then determines the possibility of the heater being ON. However, if it is unconditionally possible, an ON signal is output to the heater operation command generation circuit 41. Further, under certain conditions, that is, when the heater can be turned on by drooping the total current, a drooping command is output to the total current drooping circuit 34, and the heater operation command generation circuit 4
Outputs an ON signal to 1. Note that when turning off the heater, an OFF signal is output to the heater operation command generation circuit 41. Then, the indoor unit priority determination circuit 42 as a priority determination means outputs an ON command to each indoor control device 27 in the order of the highest priority set by the select switch 28, and outputs an OFF command in the order of the lowest priority. The operation of the heater is controlled by outputting .

FIG. 4 shows an electrical circuit diagram of the air conditioner. In the figure, 70 is a current circuit, and the first transformer 29 is disposed on the input side of this circuit 70, and the second transformer 30 is disposed on the inverter 1a side. Further, 71 indicates an inverter main circuit, which includes a rectifier circuit 72 and a smoothing circuit 7.
3. They each have a power transistor 74. Note that 75 is a motor of the compressor 1. A driver 76 provided in the outdoor control device 25 is connected to the power transistor 74. 77
is a four-way switching valve. Also, each indoor unit A to D
has an indoor control device 27, a heater 16, a heater operation switch 78, a remote control 79, and a display section 80, respectively. 81 is a signal line. That is, in this circuit, all the current consumed in this air conditioner is detected by the first transformer 29, and the current supplied to the compressor 1 side by the second transformer 30, In other words, inverter 1a
Therefore, the current flowing to the current will be detected.

FIG. 5 shows a flowchart of the overall system of the operation control mechanism. As shown in the figure, this system includes steps S1 for reading operation signals and temperature difference signals from the indoor units A to D, Step S2 of reading the mode (heating or cooling); Step S3 of calculating the total temperature difference signal ΣΔT from the above;
Frequency control using the above ΣΔT (step S4), input current droop control (step S5), heater control (step S6), peak cut control (step S
7), defrost control (step S8), and electric valve control (step S9), and then returns to step S1.

As shown in FIG. 6, the heater control (step S6) is composed of the startup heater control (step S14) and the operation heater control (step S15). (Step S14) assumes that heating operation is in progress (step S11), defrost operation is in progress (step S12), or if start-up heater control has not been completed if defrost operation is not in progress. On the other hand, the heater control during operation (step S15) is performed on the premise that the heater control during startup has been completed, and any of the above heater control (step S13) When steps S14 and S15) are completed, the next peak cut control (step S16) is started as shown in FIG.
We will move on to 7).

First, heater control at startup will be explained based on FIG. 7. First, select switch 28
(or, if not changed by the select switch, according to the standard priority set in the built-in memory), the heaters are turned on in order from indoor units A to D with the highest priority (step S21). It is determined whether there is a request (step S22). If there is a request, in the next step S23, the allowance current ΔA (breaker capacity
Compare IB - total operating current IT) with the heater current AHn of indoor units A to D, which have the highest priority. If the heater current AHn is less than the margin current ΔA, turn on the heaters 16 of the indoor units A to D.
(Step S24). In addition, the above step S2
In step 2, if there is no heater ON request and if the margin current ΔA is smaller than the required heater current AHn, the process moves to the following step S25. In step S25, the excess current ΔA at that time is
is less than or equal to 0. Margin current ΔA
is larger than 0, request for drooping by ΣΔT (step S26), stop heating operation (step S27), and set the inverter frequency upper limit (step S2).
8) On the premise that input current drooping start (step S29) is NO, the process returns to step S22 and the same procedure is repeated. In addition, in the above, the droop request by ΣΔT (step S26)
If there is, it means that there is sufficient heating capacity and the room temperature is close to the set temperature, and if the input current starts to drop (step S29), it means that the input current to the inverter 1a has reached the breaker capacity IB. Since the state is close to that of inverter 1a,
This means lowering the frequency of the input current, thereby reducing the input current. On the other hand, if the margin current ΔA is less than 0 in step S25, the heaters of the indoor units A to D having the lowest priority are turned off in step S30, and the startup heater control is completed (step S31). Also, if either the drooping request (step S26) or the heating operation stop (step S27) due to ΣΔT is
If YES, the heaters of all indoor units A to D are turned off (step S32), and the process moves to step S31. If either the inverter frequency upper limit in step S28 or the input current droop start in step S29 is YES, the process moves to step S31 to complete the start-up heater control.

Next, regarding heater control during operation, see Figures 8 and 9.
This will be explained based on the diagram. First, in step S41, it is determined whether the inverter frequency has reached the upper limit value, and in the next step S42, it is determined whether there is a higher frequency request based on ΣΔT. Step S41 and Step S
If both of 42 are YES, the process moves to step S44. If either step S41 or S42 is NO, it is determined in step S43 whether or not the input current is dropping. If this step S43 is YES, the process moves to step S44, and if it is NO, the process moves to step S53. In step S44, the presence or absence of a heater request signal from each of the indoor units A to D is checked in descending order of priority. If there is a heater request signal, the margin current ΔA is compared with the heater current AHn of the heater with the highest priority in the next step S45. If the heater current AHn is less than or equal to the margin current ΔA, the heater is turned on (step S46), and the process returns to step S45 again. Repeat until done. In the next step S47, it is determined whether the margin current ΔA is 1/2 or more of the heater current AHn and smaller than the heater current AHn. If YES in step S47, the frequency of the inverter 1a is lowered in step S62 until ΔA=AHn, that is, until the margin current ΔA becomes equal to the heater current AHn. In other words, the input current to the inverter 1a is reduced. And next step S48
The heater with the highest priority is turned on at step S49, and it is determined whether the total current IT is greater than or equal to the breaker capacity IB. Note that if the above step S47 is NO, the process directly proceeds to the following step S53. In this step S49, the total current IT is determined to be the breaker capacity.
If it is greater than IB, control is performed in step S50 to maintain the total current IT smaller than the breaker capacity IB by lowering the inverter frequency due to the total current droop, that is, by lowering the input current to the inverter 1a. , step S53
It will move to. In addition, the above step S49
If NO, in step S51, it is determined whether the total current IT is less than or equal to a predetermined current IT1 (boundary current value between the no-change area and the recovery area: for example, about IB-1A), If it is below, the inverter frequency is increased by frequency control using ΣΔT (step S52), and the inverter frequency is increased in step S53.
transition to. On the other hand, if the answer in step S51 is NO, the process goes directly to step S53 shown in FIG.
transition to.

In step S53, it is determined whether or not there is a drooping request based on ΣΔT, and if there is a request, the process proceeds to step S54.
At this point, the heater with the lowest priority is turned off, and the process moves to the next step S55. Note that if there is no drooping request in step S53, the process directly advances to step S55. In step S55, it is determined whether or not the heaters in all rooms are OFF, and if they are OFF, the process proceeds to the next step S56.
Allow for drooping due to ΣΔT. Step S5
7, the inverter input current droop starting current Ii
It is determined whether the value obtained by subtracting the inverter input current Ii from 3 is 1/2 or more of the heater current AHn.
Note that if the answer in step S55 is NO, the process directly proceeds to step S57. Step S5
7 is YES, in the next step S58, it is determined whether the value obtained by subtracting the inverter frequency F from the inverter upper limit frequency Fmax is equal to or greater than a predetermined value F1. That is, the above steps S57 and S5
8, it is determined whether the current and frequency of the inverter 1a can be further increased. If YES, turn off the heater with the lowest priority (step S59), then increase the inverter frequency by performing frequency control using ΣΔT (step S60), and proceed to the next step S6.
1, and the series of heater control during operation is completed. Note that if either of the above steps S57 or S58 is NO, the process continues to step S61.
transition to.

Next, the operating state of the air conditioner will be explained based on the above flowchart. First, if we consider the state where startup heater control has ended and transitioned to operation heater control, in this state, as is clear from the flowchart of startup heater control in Figure 7, normally the A plurality of heaters 16 or a single heater 16 is turned on, while the inverter 1a has not reached its upper limit frequency.
Then, both steps S41 and S43 in the operation heater control in FIG. 8 become NO, so
The flow passes through steps S53 and S55 in FIG. 8, and proceeds to steps S57 and subsequent steps. That is, at this stage, the heater 16 with lower priority
is turned off, and the frequency of the inverter 1a is increased by the amount of surplus current through frequency control using ΣΔT. As a result of such control, if the inverter frequency reaches the upper limit (step S41) and a higher frequency is still required in the frequency control using ΣΔT (step S42), that is, inverter 1a reaches the upper limit frequency. If the heating capacity is still insufficient, the control moves to steps after step S44 in FIG. S50), control is performed to make the total current IT smaller than the breaker capacity IB. That is, until the room temperature rises and steady heating operation can be performed, that is, in the start-up operation state, the heaters 16 are turned on in order of priority, and the corresponding amount is supplied to the inverter 1a. Control is performed to reduce the current flowing through the motor. Note that during such control, since the current value of the inverter 1a is close to the upper limit value, step S57 (FIG. 9) is executed.
The result is NO, and the heater will not be turned off. When the room temperature rises to a substantially steady state of operation, a drooping request due to ΣΔT will occur (step S53), but in this case, until the heaters 16 in all rooms are turned off (step S55), ΣΔT
(step S56), and turn off the heaters 16 in order starting from the lowest priority.
The surplus current is supplied to the inverter 1a to increase the frequency of the compressor 1 and improve the heating capacity of the heat pump.

By performing the above control, during start-up operation, as many heaters 16 as possible are turned on in order of priority to improve rapid heating, while during steady operation, the heaters 16 are turned off and the compressor is turned off. By increasing the frequency of 1, it becomes possible to perform heating operation with good energy efficiency.

In the above embodiment, the operating state determining means 44 is constituted by steps S41, S42 and S53, and the heater operation control means 43 is constituted by steps S44 to S50.

(Effects of the Invention) In the air conditioner of the present invention, as described above, when the inverter frequency reaches the upper limit in the embodiment shown in FIG. 8 and there is still a request to increase the frequency due to insufficient capacity, priority is given to the electric heater. Since electricity is supplied to the inside of the room, it is possible to improve the heating speed and perform fine-grained operation control according to the indoor situation. Furthermore, even if such control is performed, the total current is maintained below a certain value by reducing the current supplied to the compressor according to the amount of current applied to the electric heater, so the air conditioner The total current supplied will never exceed the predetermined capacity.

[Brief explanation of drawings]

The figures are for explaining an embodiment of the air conditioner of this invention, and Fig. 1 is a block diagram of the overall configuration;
Fig. 2 is a refrigerant circuit diagram, Fig. 3 is a block diagram of the control mechanism, Fig. 4 is an electric circuit diagram, Fig. 5 is a flowchart of the entire operation control, Fig. 6 is a flowchart of the entire heater control, FIG. 7 is a flowchart of heater control during startup, and FIGS. 8 and 9 are flowcharts of heater control during operation. 1... Compressor, 16... Electric heater, 19...
Refrigerant circulation circuit, 29...first transformer, 30...second transformer, 32...general current detection circuit, 36...
Input current detection circuit, 42...priority determination means,
43... Heater operation control means, A, B, C, D...
...Indoor unit, X...Outdoor unit.

Claims (1)

[Claims] 1 A refrigerant for heat pump heating that connects a plurality of indoor units A to an outdoor unit The air conditioner has a circuit 19 and an electric heater 16 disposed in each indoor unit A, and includes integrated current detection means 29 and 32 for detecting the integrated current supplied to the air conditioner. , compressor input current detection means 30, 36 for detecting the current supplied to the compressor 1, and each of the above-mentioned indoor units A...
Priority determining means 4 for determining the priority of
2. Even if the compression capacity increased according to the indoor side detection load reaches the upper limit capacity, the total current is set to be below a certain value under the condition that there is still a request to increase the compression capacity due to the indoor side detection load. Compressor 1
heater operation control means 43 for reducing the capacity of the electric heater 16 and operating the electric heater 16 in accordance with the priority order;
An air conditioner characterized by having.