KR0142279B1 - A irconditioner with compressor operating frequency control device - Google Patents

Abstract

Regarding the air conditioner capable of achieving stabilization of the refrigeration cycle and discharge temperature of the present invention, the air conditioner of the present invention is a repetition discrimination means (26) for discriminating repetition of other frequencies based on a change in frequency command. And frequency adjusting means (25) (27) (28) for selecting an intermediate frequency between two repeated frequencies in response to a frequency command and outputting it as a driving frequency of the compressor when repetition of another frequency is discriminated by means of the and plate discrimination means. It is characterized by having a.

Description

Air conditioner with compressor operating frequency adjustment means

1 is a block diagram of an air conditioner according to the present invention;

2 is a diagram showing the relationship between the temperature deviation and the S code,

3 is a diagram showing the relationship between an S code and a frequency command;

4 is a flowchart showing an outline of a control form by the apparatus of the present invention;

5 is a flowchart showing the details of the frequency stable mode determination of FIG.

FIG. 6 is a flow chart showing details of blocks 60 to 90 of FIG. 4;

7 is a time chart showing one specific example of frequency control by the apparatus of the present invention;

8 is a time chart showing one specific example of the temporal transition between room temperature and frequency in room temperature control by a conventional apparatus,

FIG. 9 is a time chart showing an example of the temporal transition between room temperature and frequency in room temperature control by the apparatus of the present invention in comparison with FIG.

* Explanation of symbols for main parts of the drawings

2: compressor 3: 4-way valve

4: indoor heat exchanger 5: expansion valve

6: outdoor heat exchanger 8: room temperature sensor

11: Rectifier 12: Inverter

13: AC motor 20: S code command means

25: division width determining means 26: repeated discrimination means

27: reference table 28: operation frequency determining means

29: driver

The present invention is to control the operating frequency of the compressor in the refrigeration cycle due to the frequency command in the air conditioner, more specifically, the indoor machine which commands a specific frequency among predetermined frequencies in step phases according to the difference between the room temperature and the set room temperature. It relates to an air conditioner.

An air conditioner which is called an inverter air conditioner and has an inverter capable of outputting an alternating frequency, and drives a compressor of a refrigeration cycle at variable speed through an AC motor according to a difference between room temperature and a set room temperature, that is, a temperature deviation, is widely used. The output frequency of the inverter in this type of air conditioner, that is, the operating frequency of the compressor, is configured to select a specific frequency from among several preset frequencies according to the temperature deviation. Therefore, there is a case in which the operating frequency of the compressor does not strictly correspond to the temperature deviation, but in this case, it is set as the average value while generating the real shortage of the actual temperature with respect to the set temperature by alternately operating between two preset frequency command values. Control is achieved in which the temperature is achieved.

This control method is very large in terms of the stabilization of the refrigeration cycle and the stabilization of the discharge temperature, and there is a problem in the stability is now a problem in the improvement of comfort. Instability of the refrigeration cycle leads to irrationality, such as the need for an additional expensive accumulator.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an air conditioner capable of achieving stabilization of a refrigeration cycle and discharge temperature.

In order to achieve the above object, the air conditioner of the present invention is repeated in response to a frequency command when the repetition of another frequency is determined by the repetition discrimination means and the repetition discrimination means for discriminating the repetition of other frequencies due to the variation of the frequency command. It is characterized in that it comprises a frequency adjusting means for selecting the intermediate frequency between the two frequencies to output as the operating frequency of the compressor.

In addition, the present invention provides a plurality of units between two frequencies repeated in response to a frequency command when a repetition of another frequency is determined by the repetition discrimination means and the repetition discrimination means. And a frequency adjusting means for dividing the frequency into frequency divisions and focusing the frequency by unit division frequency width toward the intermediate frequency between the two frequencies repeated in response to the vertical change of the frequency command and outputting the frequency as the operating frequency of the compressor. It is.

Determination of the frequency repetition due to the change of the frequency command, and when the repetition is determined, the compressor operation frequency is reduced by selecting the intermediate frequency of two repeated frequencies in response to the frequency command, thus reducing the change in the compressor operation frequency, that is, the refrigeration. Stabilization of the cycle can be achieved, and further stabilization of the discharge temperature can be achieved.

Also, the frequency repetition is discriminated due to the change of the frequency command, and when the repetition is determined, the two repeated frequencies are divided into a plurality of unit division frequency widths corresponding to the frequency command and are repeated in response to the vertical change of the frequency command. By selecting the frequency of focusing unit division frequency width toward the intermediate frequency between the two frequencies and outputting them as the operating frequency of the compressor, it is more efficient to reduce the fluctuation of the compressor operating frequency, that is, stabilize the refrigeration cycle according to the difference of the two repeated frequencies. And stabilization of the discharge temperature can be more efficiently achieved.

Referring to Fig. 1, the device configuration of the air conditioner of the present invention will be described.

The refrigeration cycle in which the refrigerant circulates is composed of a compressor (2), a four-way valve (3), an indoor heat exchanger (4), an expansion valve (5) and an outdoor heat exchanger (6), the switching state of the four-way valve (3) Accordingly, the indoor heat exchanger 4 can be operated as a condenser (heat radiator) to operate the air conditioner and the indoor heat exchanger 4 as a condenser (heat radiator) to function respectively in the heater. An indoor fan 7 and a room temperature sensor 8 are attached to the indoor heat exchanger 4, and an outdoor fan 9 is attached to the outdoor heat exchanger 6. The illustrated refrigeration cycle can change its capacity through speed adjustment of the compressor 2. The compressor 2 is variable speed driven by an AC motor 13 which is variable speed controlled by an inverter 12. The inverter 12 is supplied with a direct current from the AC power supply 10 through the rectifier 11. The indoor heat exchanger (4), the indoor fan (7), and the room temperature sensor (8) are embedded in the indoor unit and the other equipment is included in the outdoor unit.

The present invention is applicable to an air conditioner that is operated by heating and an air conditioner which is operated by cooling. An example of a case of performing a heating operation will be described below.

The indoor unit has an S code (command corresponding to frequency) according to the difference (temperature deviation) ΔTr (= Ta-Ts) of both in order to bring the room temperature Ta detected by the room temperature sensor 8 to the set temperature Ts. And S code command means for commanding the outdoor unit.

The outdoor unit divides the width determining means 25 and the repetition discriminating means 26 to perform frequency control of the inverter 12 (that is, speed control of the compressor 2) based on the S code (frequency command) received from the indoor unit. , Reference table 27, driving frequency determining means 28, and driver 29. The detail of each function of the means 25-29 is mentioned later.

4 shows the overall control flow of the air conditioner according to the present invention. On the indoor unit side, an appropriate control operation, for example, PI control operation, is performed by the S code command means 20 for the temperature deviation ΔTr = Ta-Ts (block 30), and the calculation result (ΔT). As shown in FIG. 2 according to the value of S, for example, if the temperature deviation ΔT is 0.5 or more (ΔT≥0.5), an S code that is S2 is 0 or more and less than 0.5 (0 ≦ ΔT 0.5). In the same manner, the following S code is applied to S4 if -0.5≤ △ T 0 for each change of △ T, S5 for -1.0≤ △ T-0.5, S6 for -1.5≤ △ T-1.0, and -2.0. The S code corresponding to the frequency command is output in the state of S7 for ≤ DELTA T-1.5, S8 for -2.5≤ DELTA T-2.0, and S9 for DELTA T-2.5 (block 35). In FIG. 2, the broken line shows an example of the transition of ΔT, and the same figure additionally shows the change of the S code accompanying it. Since the block 30 exists in front of the block 35, the temperature deviation (ΔTr = Ta-Ts) does not directly correspond to the S code. For example, it is assumed that the PI control operation is performed. If it stays longer than a predetermined time within the temperature deviation range, it outputs the S code of one rank (corresponding to the frequency command of one rank) to act to bring the actual room temperature Ta closer to the set room temperature Ts. The determination of the S code may be made by fuzzy control technique.

The S code output from the block 35 corresponds to each frequency command as shown in FIG. That is, S code S2 corresponds to 15 Hz, S3 corresponds to 25 Hz, S4 corresponds to 35 Hz, S5 corresponds to 45 Hz, S6 corresponds to 55 Hz, S7 corresponds to 65 Hz, S8 corresponds to 85 Hz, and S9 corresponds to 105 Hz.

The frequency corresponding to the S code output from the indoor unit is set on a step (step) as shown in FIG. 3. Therefore, in general, the preferred frequency command outputs an S code corresponding to a slightly different frequency. The control mode outputs two S codes alternately outputting an S code corresponding to an excessively compensated frequency and an S code corresponding to a frequency compensated as if insufficient for the temperature deviation.

Control operation on the outdoor unit side is performed based on the S code transmitted from the indoor unit. First, the frequency (Hz) stability mode is determined (block 40), and the mode MD is output. (Block 60). In the Hz stable mode determination block 40, it is judged as "stable operation" by confirming that the operation between two specific S codes is repeated alternately. The processing of the blocks 40 and 60 is carried out by the repeat discriminating means 26. In the mode (MD) output block 60, the division width determining means 25 outputs the S code command means 20 and the repeat discriminating means 25 outputs the S code command means 20 and the repeat discriminating means 26. Outputs a mode (MD) signal based on the output of Operation based on this mode (MD) signal, the output of the repeat discrimination means 26, the output of the S code command means 20 and the contents of the reference table (a table representing the relationship between the S code and the command frequency) 27 The frequency determining means 28 calculates an operating frequency command (block 80) and performs frequency control of the inverter 12 (i.e., frequency control of the compressor 2) via the driver 29 in accordance with the operating frequency command. do.

In the case of a control state (stable operation) in which operation between two specific operating frequencies (Hz ₁ ) and (Hz ₂ ) is repeated in such a frequency control, ΔHz = Hz ₁ -Hz ₂ is appropriately set (for example, △ It is narrowed down by Hz / 8 or ΔHz / 4 and finally adjusted to an operating frequency of approximately (Hz ₁ = Hz ₂ ) / 2 (stabilization operation). In addition, if the operating frequency coincides with the frequency of the AC power supply (50 Hz or 60 Hz), or its integer multiple, or the resonant frequency of the refrigeration cycle, various unstable conditions are generated. Avoidance control is executed (block 90).

Hereinafter, the processing performed in each block will be described in more detail. Before that, the codes used in the flowcharts are collectively described. n is a numerical value which consists of the content of the counter which counts up every time the frequency command value changes, and MD is 0-3 which shows the content of a mode as mentioned above. Sn is the S code in the count content n. S _t1 is the past S code stock, H _ztb1 is the reference frequency obtained by referring to the reference table (Figs. 2 and 3) based on the S code, and F ₁ and F ₂ are plugs for stable mode determination. (Take a value of 0 or 1.), Kc is the counter content when stable mode (MD) = 2, and Nb is a setting division between "assignment" Hz. S denotes the number of gold change steps before and after the S code change, and the S code number before the change is SF and the S code number after the change is SB, and S = SB-SF (with plus minus code). The processing contents of the frequency stable mode determination performed in block 40 will be described with reference to FIG. First, the indoor unit receives the S code (corresponding to the frequency command) and sets it to S _{n + 1} (block 41). Compare this S _{n + 1} to the one-turn S code Sn. 42)). If S _{n + 1 =} S _{n, the} current S code and the previous S code remain unchanged (ΔS = 0), and the stable mode (MD) is set to MD = 0 (block 43). To exit. In addition, MD = 0 is stable mode. If S _{n + 1} ? Sn, it is checked whether DELTA S│ = 1 (block 44). That is, it is checked whether or not the difference between the S code of the present time and the previous S code is equivalent to one step. Here, if DELTA S is not equal to 1, it is determined that the difference between the current S code and the previous S code is two or more steps, thus making it unstable, and MD = 3 (block 45) ends the routine. ΔΔS│ = 1, S _ti is the past S code data corresponding to the substituting i = 0, 1, 2, and 3 in S _{n-i + 1} for the stable mode determination. Specifically, the data is stored as S _t0 = S _{n + 1} , S _t1 = S _n , S _t2 = S _n-1 , and S _t3 = S _n-2 (block 46). Next, we check whether S _t0 = S _t2 (that is, S _{n + 1} = S _n-1 or not). (Block 47). If S _t0 ≠ S _{t2, let} plug F _{1 be} F ₁ = 0 (plug 48), if S _t0 = S _t2, F ₁ = 1 (block 49), and S _t1 = S _{Check if t3} (i.e., S _n = S _n-2, if the last and previous S codes are equivalent) (block 50). If S _t1 ≠ S _t3, F ₂ = 0 (block 51), and if S _t1 = S _t3, F ₂ = 1 (block 52), and the stable mode (MD) is MD = F ₁ , F _{If 2} + 1, F ₂ = 1 (block 52), and the stable mode (MD) is set to MD = F ₁ . If F ₂ +1, it is determined by an expression (block 53) and the series of routines ends. In block 53, when F ₁ = 1 and F ₂ = 1, that is, when it is repeatedly operated between two command frequencies (Hz ₁ ) and (Hz ₂ ) corresponding to two particular adjacent S codes. Is stable when MD = 2, and when the other one is the same S code, but the other S code is different, MD = 1 is called unstable.

The routine of the stable mode MD output (block 60), the command frequency calculation routine (block 80), and the prohibition frequency avoidance control routine (block) performed in accordance with the stable mode MD determined as described above. (90) will be described in detail with reference to FIG.

The stable mode MD (either 0 to 3) determined at block 40 is checked. If MD = 0 (i.e.,? S = 0) (block 61), this routine ends as is. When MD = 1 (that is, unstable with │ΔS│ = 1, block 62), the command frequency corresponding to HZ _{n + 1} = HZ _tb1 (S _{n + 1} ) is set to HZ _{n + 1} . The counter Kc is set to one. When the MD = 2 i.e. (│ △ S│ = stable to 1, the block (64)), │HZ _tb1 (S _t1) - it is checked whether or not the _{HZ tb1 (S n + 1 │} 15 ( block 65) . YES i.e. S _t1 command corresponding to (= the previous S code S _n) frequency S _{n + 1,} when the difference between the reference frequency corresponding to (the conference S code) over _{15Hz △ Hz (= HZ 1 -} HZ 2) The number of divisions (N _b ) between and is set to N _b = 8 (block 66), and if NO (i.e., ΔHz ≤ 15 Hz), N _b = 4 (block 67) and the command frequency (HZ). _{n + 1} ) is set to Hz ₊₁ = Hz _ant , and the incremental processing is performed with the contents of the counter as Kc = Kc + 1 (block 68), where HZ _ant is the stabilization control. Command frequency for and calculated by the following equation.

(2) The operator (INT) in the equation is an operator for taking the integer part of the operation result. (1) The right right term in the equation is the previous command frequency and the right right term is the command frequency in the present time. By applying the correction to the command frequency using this calculation result, it is possible to narrow the frequency width (ΔHz) between the two S codes in order according to the value of the division number N _b . Then, it is determined whether K _c ≤ NB (block 69, if NO (K _c N _b ), the process of K _c = N _B (block 70), YES (K _C ≤ N _b ) If MD = 3 (block (71)), the difference between the current S code and the previous S code is more than two steps, indicating that it is unstable. HZ _{n + 1} = HZ _tb1 (S _{n + 1} ) And Kc = 0 (block 72) ends the routine.

In the block 90 of the forbidden frequency avoidance control, the frequency HZ _{n + 1} calculated up to the block 72 is the operation prohibition frequency, that is, the frequency of AC power (50 Hz or 60 Hz) or an integer multiple thereof, or the resonant frequency of the refrigeration cycle. Determine whether it is included in the area (block 91), and when included therein, avoiding operation at those frequencies and modifying, for example, -3 (Hz) or +3 (Hz) for the calculated frequency Is added to be the final driving frequency command (block 92). The correction of the negative direction avoids the forbidden frequency and additionally saves energy. The correction of the positive direction avoids the forbidden frequency and improves the comfort of the air conditioner. have. The inverter 12, i.e., the electric motor 13 and the compressor 2, is operated through the driver 29 in accordance with the operation frequency command determined in this way.

7 shows one specific example of the frequency stabilization control according to the present invention.

In the example of FIG. 7, the driving frequency corresponding to the S code Sn- _{2 in} the C ₁ section is HZ ₁ (for example, S _n-2 = S8, HZ ₁ = 85HZ), and the S code in the next C ₂ section. The operating frequency corresponding to (S _n-1 ) is HZ ₂ (for example, S _n-1 = S7, HZ ₂ = 65 Hz). When transitioning from section C _{1 to} section C _2, ΔS = SB-SF = -1 and it is determined by the blocks 41 to 53 of FIG. 5 that MD = 1 is unstable. In this state, if it is changed to S code (S _n ) in the next C ₃ section, ΔS = SB-SF = -1 and HZ ₁ is commanded again as the operating frequency. Next, when the S code (S _{n + 1} ) is commanded, ΔS = SB-SF = -1, in this case, MD = 2 according to the determination result at blocks 47 to 52, and at block 65 to 68. Based on the determination result, an operation frequency of HZ ₂ + ΔHz / 8 is determined as the calculation result according to the formulas (1) and (2). In other words, since ΔHz = HZ ₁ = HZ ₂ = 85-65 = 20, N _b = 8 by blocks 65 and 66,

A state in which HZ _ant = HZ ₂ + (1/8) ΔHZ is set in the C ₄ section in FIG.

Here, if the change of the operating frequency MD = 2 and C ₅ intervals by the same calculation as described above,

Operating frequency is set.

Next, if there is a change in the operating frequency, MD = 2 and the same calculation result as above, a = 2/8 according to K _c = 3 in the C ₆ section,

The lower reference frequency is set.

In the same way, the upper operating frequency is HZ _1- (2/8) △ HZ (= 80 Hz, and the lower operating frequency is HZ ₂ + (3/8) △ Hz (= 72.5Hz). In the middle of HZ ₁ ) and (HZ ₂ ), the frequency is concentrated toward HZ _ant = HZ ₂ + (4/8) △ HZ = HZ _1- (4/8) ΔHZ. If the air conditioning capability at a specific operating frequency matches, operation continues at that specific operating frequency.

8 and 9 compare and compare the state of change of room temperature (FIG. 8) by the conventional apparatus (without the present invention) and the state of change of room temperature (FIG. 9) when the present invention is applied. It is shown so that. In both cases, the operating frequency of the room temperature Ta and the compressor 2 when the set room temperature Ta is 23 ° C. and the heating operation is performed while the room temperature Ta is around 15 ° C. (= the motor 13). Shows the temporal trend of operating frequency). In the case of the conventional apparatus (Fig. 8), it is recognized that the variation in the room temperature Ta and the operating frequency is considerably large, although the desired control result is obtained on average. In contrast, in the case of the present invention (FIG. 9), it is recognized that the room temperature Ta and the operating frequency focus at a constant value in a relatively short time, and after the focusing, they take almost a constant value with little variation.

As described above, according to the present invention, the frequency fluctuation range is narrowed, and accordingly, the operation time under the same operation frequency can be lengthened. Therefore, the refrigeration cycle is more stabilized and the discharge temperature is more stabilized. Thus, according to the present invention, it is possible to additionally achieve accumulatorless improvement by improving comfort and stabilization of the refrigeration cycle, improving the reliability of the system, reducing the cost, and improving the manufacturability.

As described in detail above, the present invention can provide an air conditioner capable of achieving stabilization of a refrigeration cycle and stabilizing a discharge temperature.

Claims (6)

In the air conditioner which controls the drive frequency of the compressor in a refrigerating cycle based on the frequency command from the indoor unit which commands a specific frequency among the frequencies predetermined in step shape according to the difference of room temperature and a set temperature, the said frequency command fluctuation | variation A repeating discrimination means for discriminating repetition of different frequencies on the basis of the? And an intermediate frequency between two frequencies repeated in response to the frequency command when the repetition of other frequencies is discriminated by the repeating discrimination means. An air conditioner having a compressor operating frequency adjusting means, characterized by comprising a frequency adjusting means for outputting as a driving frequency. The air conditioner according to claim 1, wherein the repetition judging means determines repetition when two frequency commands are output three times alternately. In the air conditioner which controls the operation frequency of the compressor in a refrigeration cycle based on the frequency command from the indoor unit which commands a specific frequency among the frequencies predetermined in step shape according to the difference between room temperature and the set temperature, the frequency command fluctuations A repeating discrimination means for discriminating repetition of different frequencies based on the? And two frequencies repeated in response to the frequency command when the repetition of other frequencies is discriminated by the repeating discrimination means as a plurality of unit division frequency widths. And a frequency adjusting means for selecting a frequency for dividing and focusing the unit divided frequency width toward an intermediate frequency between two repeated frequencies in response to a vertical change of a frequency command and outputting the frequency as an operating frequency of the compressor. Air tank with operating frequency adjustment means Group. 4. The compressor operating frequency adjusting means according to claim 3, wherein the frequency adjusting means determines the number of divisions when dividing the two frequencies into unit division frequency widths according to two repeated frequency differences. Equipped air conditioner. The compressor according to claim 1 or 2, further comprising second frequency adjusting means for outputting an intermediate frequency circumventing the prohibited frequency when the frequency selected by said frequency adjusting means corresponds to a predetermined prohibition frequency. An air conditioner having a driving frequency adjusting means. 5. Compressor operation according to claim 3 or 4, further comprising a second frequency adjusting means for outputting an intermediate frequency avoiding the prohibited frequency when the frequency selected by the frequency adjusting means corresponds to a predetermined prohibition frequency. Air conditioner with frequency adjusting means