CONTROL METHOD AND SYSTEM IN A REFRIGERATION SYSTEM AND COMPRESSOR OF A REFRIGERATION SYSTEM

Abstract

A control method and a control system for a compressor in a refrigeration system, implements control logic based on the monitoring of parameters of the refrigeration system, where these parameters may include, for example, a previous load (C.sub.ant), a current load (C.sub.atu), a reference load (C.sub.ref), a measured cycle time (t.sub.cycle) and a target time (t.sub.target).

Claims

1. A control method in a refrigeration system through the implementation of at least one general logic and one specific logic, where the general logic comprises at least on load measuring step and one cycle time measuring step, and the specific logic comprises at least one disturbance monitoring step, the compressor control method comprising the steps of: obtaining at least one previous load (C.sub.ant) and a current load (C.sub.atu); obtaining a measured cycle time (t.sub.cycle) and a target time (t.sub.target), the target time (t.sub.target) being stipulated by a user; wherein: the general logic is configured with at least one load stabilization cycle and one normal cycle; a step of obtaining a difference between the previous load (C.sub.ant) and the current load (C.sub.atu) is realized in the torque stabilization step; a step of comparing the measured cycle time (t.sub.cycle) and the target time (t.sub.target) is realized in the normal cycle, with said normal cycle being configured like an angular speed control cycle of the compressor; the specific logic is configured to realize at least the steps of monitoring a sequential set of loads (C.sub.sc), altering the angular speed of the compressor and detecting disturbances in the refrigeration system based on the cited monitoring of the sequential set of loads (C.sub.sc).

2. The control method in a refrigeration system as set forth in claim 1, wherein in the torque stabilization cycle, a step is realized of obtaining at least the previous load (C.sub.ant), the current load (C.sub.atu) and a cycle load (C.sub.cpd), where the load stabilization cycle comprises an additional step of comparing the cycle load (C.sub.cpd) with a reference load (C.sub.ref).

3. The control method in a refrigeration system as set forth in claim 2, wherein the method comprises an additional step of comparing the cycle load (C.sub.cpd) with the reference load (C.sub.ref), determining whether the cited load stabilization cycle is or is not concluded, the cycle load (C.sub.cpd) being obtained through the difference between the previous load (C.sub.ant) and the current load (C.sub.atu), where the load stabilization cycle repeats if the cycle load value (C.sub.cpd) is greater than or equal to the reference load (C.sub.ref), the load stabilization cycle being configured to optimize a refrigeration capacity of the refrigeration system and minimize a temperature homogenization time in a thermal load.

4. The control method in a refrigeration system as set forth in claim 3, wherein in the normal cycle an additional step is realized of selecting a desired angular speed (.sub.next) of the compressor, where the desired angular speed (.sub.next) of the compressor is configured to optimize the efficiency of the refrigeration system and is selected based on a comparison of the measured cycle time (t.sub.cycle) and the target time (t.sub.target), based on at least one from among a current speed (.sub.atual) of the compressor, a gain (Agr) and a speed step unit (.sub.ssu).

5. The control method in a refrigeration system as set forth in claim 4, wherein the normal cycle is configured to be realized when the load value (C.sub.cpd) is less than the reference load (C.sub.ref).

6. The control method in a refrigeration system as set forth in claim 5, wherein the specific logic is configured to control the angular speed of the compressor at the time of the detection of disturbances in the refrigeration system, the desired angular speed (.sub.next) of the compressor being configured to optimize a refrigeration capacity of the refrigeration system and to restore the system after disturbances, where the detection of disturbances in the refrigeration system occurs based on the monitoring of the sequential set of loads (C.sub.sc), the sequential set of loads (C.sub.sc) comprising n measurements of loads in a time period with a specific interval (Int), where if at least one variation pattern is detected, the angular speed of the compressor motor will be altered and the calibration will start again.

7. A control system of a refrigeration system, the control system comprising a compressor, a measuring unit, a thermostat and a data processing unit connected to each other and configured by means of an implementation of a general logic and one specific logic, where the general logic comprises at least one load measuring step and one cycle time measuring step, and the specific logic comprises at least on disturbance monitoring step, wherein: the measuring unit is configured to measure the loads in the cycles of each logic; the general logic is configured with at least one load stabilization cycle and one normal cycle; the data processing unit is configured to obtain at least one difference between a previous load (C.sub.ant) and a current load (C.sub.atu) in the load stabilization cycle; the data processing unit is configured to realize a comparison between a measured cycle time (t.sub.cycle) and a target time (t.sub.target) stipulated by a user in the normal cycle, the normal cycle being configured like an angular speed control cycle of the compressor; the measuring unit is configured at least to monitor a sequential set of loads (C.sub.sc); the data processing unit is configured at least to realize a control of the angular speed of the compressor through the monitoring of a sequential set of loads (C.sub.sc); and, the data processing unit is also configured to detect disturbances in the refrigeration system based on the monitoring of the sequential set of loads (C.sub.sc).

8. The control system as set forth in claim 7, wherein the measuring unit is configured at least to obtain the previous load (C.sub.ant) and the current load (C.sub.atu), the data processing unit being configured to obtain a cycle load (C.sub.cpd) and to compare the cycle load (C.sub.cpd) with the reference load (C.sub.ref) in the load stabilization cycle.

9. The control system as set forth in claim 8, wherein the data processing unit is configured to obtain the cycle load (C.sub.cpd) through the difference between the previous load (C.sub.ant) and the current load (C.sub.atu) obtained by the measuring unit, where the data processing unit is also configured to compare the cycle load (C.sub.cpd) to the reference load (C.sub.ref), where the load stabilization cycle repeats if the cycle load value (C.sub.cpd) is greater than or equal to the reference load (C.sub.ref), the load stabilization cycle being configured to optimize a refrigeration capacity of the refrigeration system and to minimize a temperature homogenization time in a thermal load.

10. The control system as set forth in claim 9, wherein in the normal cycle the data processing unit is configured to select a desired angular speed (.sub.next) of the compressor, where the desired angular speed (.sub.next) of the compressor is configured to optimize the efficiency of the refrigeration system and is selected by the data processing unit based on a comparison of the measured cycle time (t.sub.cycle) and the target time (t.sub.target) and based on at least one of the following: a current speed (.sub.atual) of the compressor, a gain (Agr) and a speed step unit (.sub.ssu).

11. The control system as set forth in claim 10, wherein the data processing unit is configured to realize the normal cycle when the cycle load value (C.sub.cpd) is lower than the reference load (C.sub.ref).

12. The control system as set forth in claim 11, wherein in the specific logic, the data processing unit is configured to control the angular speed of the compressor at the time of the detection of disturbances in the refrigeration system, the angular speed of the compressor is altered to optimize a refrigeration capacity of the refrigeration system and to restore the system following disturbances, where the detection of disturbances in the refrigeration system occurs based on the monitoring of the sequential set of loads (C.sub.sc), the sequential set of loads (C.sub.sc) comprising n measurements of loads in a time period with a specific interval (Int) where if at least one variation pattern is detected, the angular speed of the motor of the compressor will be altered and the calibration will begin again.

13. The control system as set forth in claim 7, wherein the refrigeration system is a refrigerator.

14. A load stabilization method of stabilizing a load in a refrigeration system, said method configured to optimize a refrigeration capacity of the refrigeration system and to minimize a temperature homogenization time in a thermal load, said load stabilization method comprising the steps of: (a) obtaining at least one previous load (C.sub.ant), one current load (C.sub.atu) and a reference load (C.sub.ref); (b) obtaining one cycle load (C.sub.cpd) through the difference between the previous load (Cant) and the current load (C.sub.atu); (c) comparing the cycle load (C.sub.cpd) with the reference load (C.sub.ref); (d) determining whether the cited load stabilization cycle is or is not concluded; where the steps (a), (b), (c), and (d) repeat if the cycle load value (C.sub.cpd) is greater than or equal to the reference load (C.sub.ref).

15. A method of controlling of the angular speed of a compressor to optimize efficiency of a refrigeration system, said method comprising: obtaining a measured cycle time (t.sub.cycle) and a target time (t.sub.target), where the target time (t.sub.target) is stipulated by a user; comparing the measured cycle time (t.sub.cycle) and the target time (t.sub.target); selecting a desired angular speed (.sub.next) of the compressor, where the desired angular speed (.sub.next) of the compressor is selected based on the comparison of the measured cycle time (t.sub.cycle) and the target time (t.sub.target) and based on at least one of the following: a current speed (.sub.atual) of the compressor, a gain (Agr), a speed step unit (w.sub.ssu).

16. A method of detecting disturbances in a refrigeration system, said method comprising: monitoring a sequential set of loads (C.sub.sc); altering an angular speed of a compressor based on the monitoring of the sequential set of loads (C.sub.sc), where the angular speed of the compressor is altered to optimize the refrigeration capacity of the refrigeration system and to restore the system following disturbances; detecting disturbances in the refrigeration system based on the sequential set of loads (C.sub.sc), where the detection of disturbances in the refrigeration system occurs based on the sequential set of loads (C.sub.sc), the sequential set of loads (C.sub.sc) comprising n measurements of loads in a period of time with a specific interval (Int) where if a pattern is detected, the angular speed of the compressor motor will be altered and the calibration will begin again following the stabilization of the refrigeration system, and if nothing is detected, the samples of the sequential set of loads (C.sub.sc) are shifted and another sample is verified following the interval (Int).

Description

SUMMARIZED DESCRIPTION OF THE DRAWINGS

[0019] The present invention shall be described in more detail below based on an example of execution represented in the drawings. The figures show the following:

[0020] FIG. 1is a waveform of the speed and temperature of the load;

[0021] FIG. 2is an exemplification of a cycle which ends before 50% of a target time;

[0022] FIG. 3is an exemplification of a cycle which ends between 50% and 80% of a target time;

[0023] FIG. 4is an exemplification of a cycle which ends between 80% and 100% of a target time;

[0024] FIG. 5is an exemplification of a cycle which ends after a target time;

[0025] FIG. 6is an exemplification of a complete waveform using unit gain, from the moment when the inverter is switched on;

[0026] FIG. 7is an exemplification of a complete waveform a gain equal to two, from the moment when the inverter is switched on;

[0027] FIG. 8is an exemplification of a complete waveform with a given number of steps that will occur in a cycle.

DETAILED DESCRIPTION OF THE FIGURES

[0028] In principle, the present invention concerns a method and system for controlling a compressor in a refrigeration system. Refrigeration system hereby preferably means a system configured in devices and equipment such as fridges, freezers, and refrigerators in general both for domestic use (household appliances) and for commercial use.

[0029] Moreover, the compressor to which the present invention refers to is configured as a variable speed compressor. More specifically, the cited compressor is configured in order to be compatible with the features of the method and system that are also the object of this invention.

[0030] In a general sense, the present invention is preferably configured through the implementation of at least on control logic based on the monitoring of parameters of the refrigeration system, which will be described in more detail below.

[0031] As such, in one configuration of the present invention, for the effective implementation of this logic, the control method of the compressor is configured to perform, in a general sense, at least the following steps: [0032] Obtaining a previous load (C.sub.prev) and a current load (C.sub.atu); [0033] Obtaining a measured cycle time (t.sub.cycle) and a target time (t.sub.target), where the target time (t.sub.target) is stipulated by a user.

[0034] It is important to observe that in one configuration, the previous load (C.sub.prev) and current load (C.sub.current) are obtained, for example, based on a measurement of torques. However, these loads may alternatively be obtained through the measuring and/or verification of other features related to the load of the refrigeration system, such as electric current, for example.

[0035] Obviously, the nature of said loads is not a limitation of the present invention, such that the objectives of the present invention may be achieved by verifying different features.

[0036] In addition to this, it is observed that the target time (t.sub.target) may be configured like an on time or an off time, or even as a running time ratio, for example.

[0037] One configuration of the control method of a compressor in a refrigeration system occurs through a general logic and a specific logic.

[0038] The general logic which comprises the method which is the object of the present invention basically concerns the behavior expected of a compressor of the refrigeration system during its entire working time and the principal routine of this resource. In one configuration, this logic can be divided into cycles, comprising a pull-down cycle and a normal cycle, for example.

[0039] When an inverter of the refrigeration system is energized, a pull-down state is configured. In this state, the compressor operates at an optimum (ideal) speed, such as a permitted maximum speed, and may also operate at intermediate speeds before achieving the optimum speed. Either way, this operation of the compressor is configured to generate more cooling capacity of the refrigeration system to reduce a pull-down time (set point, which is to say, the time for a given temperature to be reached by the refrigeration system, achieving stability). This state is maintained until the pull-down cycle (state) ends.

[0040] To identify the end of the pull-down state, when a thermostat of the refrigeration system is switched off, the system compares a final load measured with the same measurement of the previous cycle. If this variation is within an interval, the pull-down will be concluded; if not, the system repeats this procedure.

[0041] As such, the general logic comprises at least on step of measuring loads (pull-down cycle) configured at least with one load stabilization cycle and one cycle time measuring step being configured as a normal cycle.

[0042] In this configuration, the following steps are performed: [0043] Obtaining a difference between the previous load (C.sub.ant) and the current load (C.sub.atu) in the torque stabilization cycle; [0044] Comparing the cycle time measured (t.sub.cycle) and the target time (t.sub.target) in the normal cycle, with the normal cycle being configured as an angular speed control cycle of the compressor.

[0045] As previously mentioned, the method of the present invention comprises a step of obtaining a previous load (C.sub.ant) and a current load (C.sub.atu).

[0046] As such, it is observed that in one configuration, in the load stabilization cycle, a step is realized of obtaining at least one previous load (C.sub.ant), the current load (C.sub.atu) and a cycle load (C.sub.cpd).

[0047] Moreover, the load stabilization cycle comprises an additional step of comparing the cycle load (C.sub.cpd) with a reference load (C.sub.ref), which reference load (C.sub.ref) is previously stipulated. Based on this comparison, it is determined whether the cited load stabilization cycle is or is not concluded. If it is not, the comparison of the load values is repeated, as previously mentioned. It is observed that this step characterizes a verification of the conclusion or otherwise of the cited load stabilization cycle. This is because a thermal load of the refrigeration system tends to decrease over time, causing the obtained load cycle (C.sub.cpd) to also decline, but with the compressor motor's losing rotation, which can be kept constant. It is noted that the load stabilization cycle is configured to optimize a refrigeration capacity of the refrigeration system and minimize a temperature homogenization time in a thermal load.

[0048] It is also important to note that the cycle load (C.sub.cpd) is preferably obtained through the difference between the previous load (C.sub.ant) and the current load (C.sub.atu).

[0049] In this scenario, as previously described, the load stabilization cycle repeats while the cycle load (C.sub.cpd) is greater than, or equal to, the reference load (C.sub.ref).

[0050] To exemplify this configuration, FIG. 1 shows a waveform of the speed and temperature of the load. It is possible to observe in this figure that the variation in load between cycles indicates that the temperature of the load is still not stable (uniform) and the system should remain in the load stabilization cycle.

[0051] However, when the load variation (points A and B in FIG. 1, for example) is within a specified interval, which is to say, cycle load (C.sub.cpd) less than the reference load (C.sub.ref), it is understood that the temperature is uniform and stabilized. So the refrigeration system may alter its operation for the subsequent cycle, which is to say, for the normal cycle.

[0052] Also regarding FIG. 1, it is important to note that the thermostat can switch off the refrigeration system at any time, even without the thermal load having been stabilized. As such, a sensor of the thermostat may detect the temperature of the set point and switch off the refrigeration system depending on its position and on an airflow of the system, for example, even if the temperature is not homogeneous. In addition to this, the cycle may be interrupted to cause a defrosting cycle, if disturbances are detected.

[0053] It is noted regarding FIG. 1 that the load stabilization cycle (or pull-down cycle) may be seen during five cycles. After this, when the stabilization point is reached, which is to say, the current load (C.sub.atu) is lower than the reference load (C.sub.ref), the operation of the refrigeration system is altered to the normal cycle.

[0054] It should be noted that there is no extra sensor like the temperature sensor in the present invention. As such the magnitudes related to the temperature of the thermal load are inferred from the electrical magnitudes of the compressor, as already described. Moreover, thermal loads may be understood, for example, as objects to be refrigerated by the refrigeration system.

[0055] Regarding the normal cycle, this must be understood as a routine configured to select the best speed to operate the compressor, in order to achieve the desired cycle time. This cycle time is defined by the user through a specific interface, such as a computer program, tool or application.

[0056] As previously mentioned, the method of the present invention comprises a step of obtaining a measured cycle time (t.sub.cycle) and a target time (t.sub.target), where the target time (t.sub.target) is stipulated by a user. It should be observed that the target time (t.sub.target) may be configured like an on time, off time or also as a running time ratio, for example. As such, in one configuration, this step is performed in the normal cycle.

[0057] Furthermore, the normal cycle may comprise an additional step of comparing the measured cycle time (t.sub.cycle) and the target time (t.sub.target) and an additional step of selecting a desired angular speed (.sub.next) of the compressor, where the desired angular speed (.sub.next) of the compressor is configured to optimize the efficiency of the refrigeration system.

[0058] In one embodiment, the desired angular speed (.sub.next) of the compressor is selected based on at least one of the following: a current speed (.sub.current) of the compressor, a gain (Agr) and a speed step unit (.sub.ssu), also taking into account the result obtained from the comparison between the measured cycle time (t.sub.cycle) and the target time (t.sub.target).

[0059] To exemplify this configuration, four possible scenarios are listed below, related to the selection of the desired angular speed (.sub.next) in relation to the parameters previously mentioned. In these examples, it is observed that the speed step unit (w.sub.ssu) assumes a value of 200 rpm and the gain (Agr) must be understood as a previously stipulated parameter. It is important to note that these are only examples of one possible configuration of the present invention, and do not have a limiting character in relation to the same:

[0060] Scenario A: t.sub.cycle<0.5*t.sub.target

[0061] In this case, when the cycle ends before 50% of the target time (t.sub.target), the compressor will reduce 3 speed steps multiplied by the gain (Agr), as exemplified in FIG. 2 considering a target time (t.sub.target)of 100 minutes:

.sub.next=.sub.atual(3*Agr*.sub.ssu) Eq. 1

[0062] Scenario B: 0.5*t.sub.target<t.sub.cycle<0.8*t.sub.target

[0063] In this case, when the cycle ends between 50% and 80% of the target time (t.sub.target), the compressor will reduce 1 speed step, as exemplified in FIG. 3 considering a target time (t.sub.target) of 100 minutes:

.sub.next=.sub.atual(.sub.ssu) Eq. 2

[0064] Scenario C: 0.8*t.sub.target<t.sub.cycle<t.sub.target

[0065] In this case, when the cycle ends at between 80% and 100% of the target time (t.sub.target), the compressor will maintain the same speed for the next cycle, as exemplified in FIG. 4 considering a target time (t.sub.target) of 100 minutes:

.sub.next=.sub.atual Eq. 3

[0066] Scenario D: t.sub.target<t.sub.cycle

[0067] In this case, when the cycle exceeds the target time (t.sub.target), the system increases the speed by 1 speed step multiplied by the gain (Agr) with each given period of time, as exemplified in FIG. 5, considering a target time (t.sub.target) of 100 minutes and a time period of 20 minutes for increments in speed. So the last speed will be the next speed:

.sub.next=.sub.atual+(Agr*.sub.ssu) Eq. 4

[0068] It is also important to note that the present invention may be configured to also act in a particular case, scenario D, where the target time (t.sub.target) is less than the cycle time (t.sub.cycle) and the system remains at a given speed for a short time (less than the period of time stipulated20 minutes, in the case of the example mentioned, which is to say, it remains at this speed only for a portion of the stipulated period of time and not for the entire period of time). In this case, the next speed (.sub.next) will be configured as the speed prior to the last speed (.sub.actual1), namely:

.sub.next=.sub.atual1 Eq. 5

[0069] FIG. 6 represents a complete graph using the unit gain (Agr) (Agr=1), from the moment when the inverter is switched on. In this figure, after being switched on, it is observed that the refrigeration system remains in the load stabilization cycle for the first four cycles. After this, the speed is adjusted until the cycle attains the desired time (first and second cycles). In the third cycle, it is observed that the system is stable.

[0070] If, for some reason, the target time (t.sub.target) elapses without switching off the compressor, the speed will be increased, for example, every 20 minutes, as is observed in the fourth and fifth cycles. Based on the previous examples, it is observed that if the user wishes to alter the gain (Agr) it is possible to make the system more or less aggressive.

[0071] So, like FIG. 6, FIG. 7 also represents a complete graph, but using a gain (Agr) equal to two (Agr=2).

[0072] Obviously, the values previously cited are mere possible examples to be used in the present invention and should not be understood as limiting characteristics thereof.

[0073] It is important to observe that, in one configuration, other parameters related to the refrigeration system or components connected to it may also be used to select the desired angular speed (.sub.next) of the compressor, such as capacity, current or the instantaneous speed of the compressor, for example.

[0074] The results principally exemplified in FIGS. 6 and 7 were obtained using constant speeds during the cycle. This means that the speed is altered only between the cycles or when the target time (t.sub.target) has elapsed.

[0075] However, one configuration of the present invention also allows for the configuration of a number of steps (n.sub.etapas) which will occur in the cycle. With this parameter, the control increases the speed based on the target time (t.sub.target) and target considering the number of steps (n.sub.etapas) plus one unit (which is to say, n.sub.etapas+1).

[0076] So, for example, if the target time (t.sub.target) is sixty minutes and the number of steps (n.sub.etapas) equal to 3 (which is to say, t.sub.target=60 min and n.sub.etapas=3), the speed will increase every 15 minutes, as exemplified in FIG. 8.

[0077] As such, as can be observed principally in the examples and embodiments described above, said normal cycle is configured as an angular speed control cycle of the compressor.

[0078] Regarding the specific logic, this is configured as a routine which principally monitors the torque of a motor of the compressor, which is proportional to the temperature of the load. This monitoring occurs to address disturbances and exceptional cases of the system.

[0079] Such disturbances comprise, for example, the opening of the fridge door, hot gas resistance, defrosting, etc. In a general sense, the disturbances can be understood as specifically thermal disturbances which can cause in increase of thermal load in the refrigeration system.

[0080] Based on the torque variation curve, it is possible to detect signatures (patterns, fingerprints) and to take decisions related to the operation of the compressor such as a change, or not, in its speed.

[0081] As such, the specific logic comprises at least one step of monitoring disturbances, allowing the refrigeration system to operate in extreme and unusual situations.

[0082] To this end, the specific logic is configured to realize at least the following steps: [0083] Alter the angular speed of the compressor through the monitoring of a sequential set of loads (C.sub.sc); [0084] Detect disturbances in the refrigeration system based on the sequential set of loads (C.sub.sc).

[0085] As such, the specific logic operates in parallel with the general logic, such that its operation begins after the stabilization of the system and is periodic. Moreover, this logic is configured to control the angular speed of the compressor at the time of the detection of disturbances in the refrigeration system, where the detection of disturbances in the refrigeration system occurs based on the sequential set of loads (C.sub.sc), where the angular speed of the compressor is altered being configured to optimize a refrigeration capacity of the refrigeration system and achieve a target temperature.

[0086] Regarding the cited sequential set of loads (C.sub.sc), this can be understood as a set of measurements of at least a magnitude related to the refrigeration system, where the measuring may be realized, for example, in a given period of time, with intervals (Int) that are also predetermined.

[0087] To exemplify one possible characteristic of the cited sequential set of loads (C.sub.sc), in one possible configuration this set comprises n measurements (calibrations) of torque, in a period of time, where samples are calibrated with a specific interval (Int).

[0088] Following the third calibration, the samples of the sequential set of loads (C.sub.sc) are analyzed with the aim of detecting a load variation pattern through possible variations in the magnitude verified, in the case of the torque. If a pattern is detected, the angular speed of the motor of the compressor will be altered and the calibration will begin again after the stabilization of the refrigeration system. Otherwise, if nothing is detected, then the samples of the sequential set of loads (C.sub.sc) are shifted (the first is discarded, the second becomes the first, the third becomes the second and so on) and another sample is calibrated after the interval (Int).

[0089] Again, it should be highlighted that the values mentioned are mere examples and should not be taken as limitations of the invention. In addition to this, alternative configurations may comprise, for example, using closed groups of magnitudes to form the sequential set of loads (C.sub.sc) or even increments over time, such that the configuration with shifts mentioned above should not be understood as a limitation for the present invention.

[0090] Specifically regarding the detection of patterns (fingerprints), these can be based on a calculation of torque variation (1, 2), as previously described and also as described in the formulas below, with an exemplification shown in FIG. 9. It should be observed, in this example, that the sequential set of loads (C.sub.sc) is composed of measured loads 1, 2 and 3 (C.sub.med1, C.sub.med2 and C.sub.med3 respectively). Thus, we observe:

[00001]$\begin{array}{cc}.Math..Math.1=\frac{C_{\mathrm{med}.Math..Math.2}-C_{\mathrm{med}.Math..Math.1}}{C_{\mathrm{med}.Math..Math.1}}*100& \mathrm{Eq}..Math.4.Math.a\\ .Math..Math.2=\frac{C_{\mathrm{med}.Math..Math.2}-C_{\mathrm{med}.Math..Math.1}}{C_{\mathrm{med}.Math..Math.1}}*100& \mathrm{Eq}..Math.4.Math.b\end{array}$

[0091] So, the parameters calculated (1, 2) are compared with reference parameters, such as those illustrated in FIG. 9.

[0092] One configuration also provides for the detection of disturbances when the refrigeration system is disconnected, which is to say, when there are no parameters (measured loads), for example of torque, to be measured and considered.

[0093] So, to detect disturbances which may occur when the system is disconnected (there is no torque to measure), the variation in the first load measured is used, which is to say, the load measured with the refrigeration system already stable, after being switched on.

[0094] If this measure varies more than a pre-established limit, such as 30% of the last cycle, it is understood that a disturbance occurred while it was disconnected, such that the angular speed of the motor is defined for a maximum value.

[0095] So, based on the characteristics described, a method is foreseen configured principally to identify and correct disturbances in the refrigeration system and to activate the compressor at an angular speed of greater efficiency for the cited refrigeration system.

[0096] It is important to note that said efficiency of the refrigeration system may be different from the efficiency of the compressor motor in isolation. As such, in other words, the present invention is configured as described to activate the compressor at optimum angular speed for the cited refrigeration system, and may or may not be equal to the optimum speed of the compressor itself.

[0097] The present invention also comprises a compressor control system in a refrigeration system.

[0098] The system basically comprises a compressor, a measuring unit, a thermostat and a data processing unit, being configured by means of the implementation of at least one general logic and one specific logic, with the previously mentioned characteristics.

[0099] Regarding the components of the present system, the compressor is configured like a variable capacity compressor.

[0100] While the measuring unit is configured like a device capable of measuring loads as previously described, such as torque, current and electrical tension.

[0101] The thermostat, in turn, is configured to verify data related to heat exchange and temperature variation in the refrigeration system.

[0102] The data processing unit is configured to receive data verified from the other components and to act principally on the refrigeration system, to command the realization of steps, cycles and actions as previously described.

[0103] In the context of the present invention, these principal components comprise a control system configured thus to allow the implementation of the control method described previously

[0104] In addition to this, it is worth mentioning that this system also comprises at least one environment to be refrigerated, so that the calibrations principally related to heat exchange and temperature variation in the refrigeration system are realized in this environment.

[0105] Moreover, it is observed that a refrigerator may be configured in accordance with the present invention, being thus equipped with a refrigeration system to allow for the implementation of the control method hereby described.

[0106] Finally, the present invention also comprises a compressor configured like the method and system previously described, where said compressor is preferably configured like a variable speed compressor compatible with the characteristics described above.

[0107] Having provided a description of an example of a preferred materialization, it should be understood that the scope of the present invention encompasses other possible variations, being limited only by the contents of the attached claims, with the possible equivalents thereby included.