JPS61180873A - Controller for refrigerator, etc. - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to a control device for a refrigerator or the like, and particularly to one that controls the temperature inside the refrigerator by adjusting the rotation speed of an electric compressor of a cooling unit.

(b) Prior Art A conventional control device of this type is disclosed in, for example, Japanese Patent Application Laid-Open No. 101281/1983. The configuration shown in the publication increases or decreases the cooling capacity of the cooling unit by controlling the rotation speed of the motor of the electric compressor using an inverter system, and when the internal temperature falls below the set temperature, the rotation speed is lowered and the set temperature When it gets higher, the rotation speed is increased. According to this, for example, the upper limit temperature and lower limit temperature are determined based on the set temperature, the motor of the electric compressor is started at the upper limit temperature, and the motor is stopped at the lower limit temperature. The number of times the motor starts and stops is significantly reduced, improving motor durability and reducing power consumption. In addition, the fluctuation range of the temperature inside the refrigerator is also reduced, which can be expected to improve the shelf life of foods and the like.

(/→ Problems to be Solved by the Invention Although the configuration described in the above publication has the above-mentioned effects, in reality, even if the rotational speed of the motor changes, the cooling capacity changes immediately. Moreover, since the temperature inside the refrigerator has inertia due to the heat load inside the refrigerator, the width of the so-called overshade and undershade is large around the set temperature, and therefore the temperature fluctuation within the thickness is still large (as well as There are problems such as a long time required for the overshoot and undershoot to converge.

(b) Means for solving the problem In order to solve the problem, the present invention provides an electric compressor (
Adjust the rotation speed of c) to bring the internal temperature (T,) to the set temperature (T,).
Based on the temperature detection means (1) that detects the temperature (T,), the rotation speed is adjusted every time the temperature changes by a predetermined value, and the rotation speed is adjusted depending on the time required for the temperature change. A control means (141) is provided for changing the amount of change in rotation speed.

(E) Function According to the present invention, the amount of change in capacity of the electric compressor can be adjusted according to the degree of temperature change, so the follow-up performance for load fluctuations is high, and there is little overshoot and undershoot near the set temperature. can.

(F) Embodiment As shown in FIG. 1, the present invention includes a temperature detection means (1) for detecting the internal temperature (T, ) of a refrigerator (not shown) and a temperature setting means (2) that is operated by the user. by temperature (T,)
Means (3) for setting a dead zone, means (4) for setting an upper limit temperature (T, ) above and below the dead zone, and a lower limit temperature (TL)
means (5) for setting the temperature, means (7) for receiving the output of the temperature detecting means (1) via the switch (6) and storing the temperature information, and controlling the temperature of the means (11 and (7)). Temperature change determining means (8) that compares outputs and generates an output when a predetermined temperature change occurs, for example, a 1°C difference; and a similar busy means (1).
A capacity increase/decrease determination means (9) that compares the temperature outputs of and (7) and changes the output depending on whether the internal temperature (T, ) has increased or decreased, and an integrated value when the output of the temperature change determination means (8) is generated means (means all for reading the integrated value of 1z, determining the amount of change in capacity based on the value, and generating an output; and each means f3
1(41(51181(9)) and (ill), which is included in the electric compressor which will be described later, and which controls the motor (1(l) whose rotational speed is adjusted 0). 141.

The control means α generates an output to change the rotational speed of the motor σl when the output of the mechanical means (8) is generated, and the means (9)
If the temperature change increases based on the output of the motor (1 (
Increase the rotation speed of I, and if it is falling, lower the rotation speed. Here, the integrated hand fat z is reset and starts integration after the control means I finishes processing due to the previous generation of the output of the means (8), and the means (old) is reset by the means C12 when the output of the means (8) is generated.
Since the integrated value of 1 is read, the result is the means (11
) reads information on the time required for a change of 1°C, and the means fiυ changes the output according to this time value and inputs it to the control means 114; For example, when it is longer than 10 minutes, the control means α41&! Let the amount of change in the rotation speed mentioned above be 1 step (for example, 15H7 as the operating frequency), and set it to 10
If the time is within minutes, this is considered as 2 steps.

Furthermore, the control means (141) does not change the rotation speed of the motor not in the dead zone including the set temperature (TD) of the thickness inner temperature (T, ) set by the means (3), and the upper limit set by the means (4). At temperature (T8), the rotation speed of the motor QOI is set to the maximum capacity (for example, 120 Hz in terms of operating frequency), and at the lower limit temperature (TL) set by means (5), the rotation speed of the motor QOI is set to the minimum capacity (in terms of operating frequency, for example, 120 Hz). For example 3
0 Hz). Moreover, when the above processing is completed, the control means I opens the switch +61 and controls the temperature (T, ) at that time.
is written in the means (7) and the integration means (12+ is reset. Therefore, the means 181 (91) calculates the previous temperature (Tpo) written in the means (7) and the current temperature (Tp+) from the means (1). As well as comparing the means (
121 is reset and starts integration, so the means αD
will read the time required for the temperature (T, ) to change by 1°C.

FIG. 2 is a block diagram showing the relationship among the detection means (1), etc., the means for adjusting the rotation speed of the motor QQI, and the hardware of the microcomputer. Microcomputer (
Reference numerals 151 refer to dead zone setting means (3), upper limit temperature setting means (4), lower limit temperature setting means (5), switch (6), temperature information storage means (7), and temperature change determination means (
8), ability increase/decrease determination means (9), ability change amount determination means (
111, the outputs of the micro CPU (16), the temperature detection means (1), and the temperature setting means (2) having the functions of the integration means a3 and the control means α are connected to the A/D conversion section (171).
It has the function of inputting to the micro CPUrle after digital conversion by u.

The output of the micro CPU (16) is sent to the D/A converter 9.
The signal is inputted to the inverter circuit (2), converted into a three-phase frequency, and thereby drives the motor Qtll. Motor 0
1 is a three-phase synchronous motor. Also, Fig. 3 shows the refrigerant circuit of the refrigerator, where Q3 is an electric compressor driven by the motor (101), 241 is a condenser, ■ is a capillary cheep as a pressure reducer, [26+ is an appropriate position in the refrigerator] This is a cooler installed in a refrigerator, and is filled with a predetermined refrigerant.

Next, FIG. 4 shows a flowchart showing the software of the microcomputer. The start is when the refrigerator is powered on, and after resetting everything in step C3]) GS5, start the rotation speed of the motor αα (for example, 20Hz as the operating frequency) to the maximum capacity (120Hz).
Hz), and when the maximum capacity is reached, proceed to step (To) until the internal temperature (T,) reaches the upper limit temperature (T9), for example -1
Determine whether the temperature has reached 5°C or not, and if it has not, maintain that state. Temperature (T,) is -15℃ at step (to)
When the temperature is reached, proceed to step (1), reset the integration means (1z), and in step (c) write the temperature (T,) at that time, that is, -15°C, into the temperature information storage means (7), and proceed to step (to). Proceed. Step (to) C37) means (7)
The means (121 integrates, step C3?) until the difference between the internal temperature (Tpo) written in and the current temperature (Tpl) detected by means (1) becomes 1°C. ℃
When the temperature (T□) reaches -15°C at the step (to)
It is determined whether the temperature (T□) is the lower limit temperature (TL), for example -21° C., and if it is negative, the flow advances to step (4G).

Step (In 4G, judge whether the temperature (T□) is within the dead zone of the internal temperature.Here, the set temperature (T,) is -1
8°C, and the dead zone is a temperature range lower than -17°C above and below it and higher than -19°C. Therefore, since the temperature (TPI) at step (4G) is not in the dead zone, it is determined whether the temperature (TPI) has risen or fallen from (T,.) at step (4B), and it is lowered to -16℃.
If so, proceed to step (421), set the rotation speed change direction to the descending mode, and judge whether the motor αα has the minimum capacity in step 03, and if no, proceed to step (44). Cumulative time of means σ2, i.e. 1°C
Determine whether the time required for the change is less than 10 minutes or longer, and if it is less than 10 minutes, proceed to step S.
Lower the rotation speed of ■ by 2 steps, and if it is longer than 10 minutes, proceed to step (4e+), lower the rotation speed by 1 step, return to step (9), reset the means (12+), and at step (to) the temperature at that time. That is, -16°C is written.

After that, when the cooling progresses and the temperature (T, υ - - 17 degrees Celsius), execute steps 037 to (461) and further lower the rotation speed of the motor (101 by 2 steps or 1 step, step ( b) Return to means Q2
1 and write -17°C in (g). When the temperature further decreases to -18° C. which is the set temperature (To), the process moves from step (37) to C31, and from step CG to step 0η. In step 07), the motor aα
Return to step (2) without changing the rotation speed. That is, in the dead zone, the rotation speed of the motor αC does not change. The rotation speed of motor QO+ at this time is 60H as the operating frequency.
z.

It is either 751'lZ or 901Z.

The cooling capacity in this state is in excess of the load, and if the temperature (Tpl) drops to -19°C, step 6
Execute steps from 7) to (c) or (46) to increase the rotation speed to 2.
Lower the rotation speed by a step or one step, and if the temperature drops further to -20°C, lower the rotation speed in the same way. After that, when the temperature (TPI) reaches the lower limit temperature (TL) of -21°C, proceed from step C31 to (4ε) and set the rotation speed of the motor (101) to the minimum capacity (30Hz). If the temperature inside the refrigerator (T,) is set so that it rises even under the lightest load condition, further temperature drop can be prevented.
Overcooling inside the refrigerator is prevented.

Furthermore, since the motorization uses a three-phase synchronous motor, the minimum capacity can be set lower than that using a three-phase induction motor. As a result, when the temperature (Tpt) rises to -20°C, the process proceeds from step (41) to (4 scratches), the rotational speed change direction is set to rising mode, and in step 60 it is determined whether or not the maximum capacity is reached. Steps from (from 44 (
c) Or (proceed to step 41 and increase the rotation speed by 2 steps or 1 step. After that, the temperature (T2.) rises to 119.
When the temperature reaches ℃, the rotation speed is further increased by 1 or 2 steps. If it remains in the dead zone, it will maintain that state without changing the rotational speed. The rotational speed at this time is also 60 to 175 Hz or 90 Hz in terms of operating frequency.

By repeating the above, the temperature (T,) converges within the dead zone, but for example, in this state, the heat load inside the refrigerator increases rapidly,
When a sudden temperature rise occurs, step C is performed when the temperature ('rp+) reaches the upper limit temperature (T, ) of -15°C.
(Proceeds from 1 to eill and the motor (1G+ rotational speed is set to its maximum capacity, so the temperature rise can be kept to a minimum.

Furthermore, since the motor Gα is operated at maximum capacity even after the power is turned on until the upper limit temperature (T3) of −15° C. is reached, the cooling speed after the power is turned on becomes faster. Further, according to the present invention, the rotation speed of the motor (101) is corrected every time the temperature changes by 1°C, and the amount of correction is also changed depending on the time required for the temperature to change by 1°C. If it is long,
In other words, when the degree of temperature change is slow, the amount of change in rotational speed is small, and when the time is short, that is, when the temperature change is rapid, the amount of change in rotational speed is large.
, ), and the rotation speed can be adjusted sufficiently in advance as it approaches the dead zone, so the so-called overshoot and undershade width are small, and the set temperature (
Convergence to TI) is also quick.Furthermore, the rotation speed that remains constant within the dead zone depends on the load situation at that time or the set temperature (T,).
In the example, the operating frequency is 60Hz,
It will be either 75Hz or 90Hz. Therefore, the degree of freedom in setting the temperature is high, and the adaptability to the load is also good.

Incidentally, if the minimum ability or maximum ability is already reached in step 03 or gloss, both return to step (goods). still,
Each set value in the embodiment is not limited to that, and although the variation in the rotation speed is changed in two steps in the embodiment, it may be changed more finely.

(G) Effects of the Invention According to the present invention, since the rotational speed of the electric compressor is adjusted to change the cooling capacity, the number of starts and stops of the electric compressor is significantly reduced, and durability can be improved and the storage Fluctuations in internal temperature are also small, and food preservation is significantly improved. Furthermore, according to the present invention, the rotation speed is adjusted every time the temperature changes by a predetermined value, and the amount of change is changed depending on the time required for the temperature change.
In the case of sudden temperature changes, it is possible to increase the amount of change, and the ability to follow temperature changes is good.In addition, the electric compressor's capacity can be adjusted sufficiently as the set temperature approaches, so overshoot and undershoot can be avoided. It is possible to significantly reduce the size of the chute and further improve the preservation of food.

[Brief explanation of the drawing]

Each figure shows an embodiment of the present invention. Figure 1 is a functional block diagram, Figure 2 is a block diagram showing the relationship between each input, motor, etc. and the hardware of the microcomputer, and Figure 3 is a refrigerant circuit diagram. , FIG. 4 is a flowchart showing the software of the microcomputer. (1)...Temperature detection means, (2)...Temperature setting means, (8)...Temperature change determination means, (9)...Capacity increase/decrease determination means, (IQl...Motor, α1 )・・
・Capacity change amount determination means, (12...integration means, En...control means, (c)...electric compressor. Applicant Sanyo Electric Co., Ltd. and one other representative Patent attorney Masao Sano Prize 4 + '21 Coin S2 Figure No. 30

Claims (1)

[Claims] 1. In a device that controls the internal temperature to a set temperature by adjusting the rotational speed of an electric compressor, the rotation speed is increased every time the temperature changes by a predetermined value based on a temperature detection means that detects the internal temperature. A control device for a refrigerator, etc., comprising a control means for adjusting the number of rotations and changing the amount of change in the rotation speed depending on the time required for the temperature change.