System and method for feeding and controlling a variable capacity compressor, a variable capacity compressor and a cooler comprising a variable capacity compressor

Abstract

A variable capacity compressor (100), a cooler (200) including same, and a method and system for controlling a variable capacity compressor are disclosed. An electronic control (50), a thermostat (30) and a power source (10) are disclosed, the power source including a neutral terminal and a phase terminal, the thermostat including a first terminal and a second terminal, and the electronic control including a phase feed input and a neutral feed input, the neutral terminal of the power source electrically connected to the neutral feed input of the electronic control and the phase terminal of the power source electrically connected to the first terminal of the thermostat, the second terminal of the thermostat connected electrically to the phase feed input of the electronic control, the thermostat configured to feed and un-feed selectively the electronic control, the electronic control activating and deactivating selectively the compressor and controlling its cooling capacity according to signals from an operation state sensor (40).

Claims

1. A system for feeding and controlling a variable capacity compressor (100) in a cooled environment (200), said system comprising: an electronic control (50), a thermostat (30) arranged in the cooled environment (200), at least one operation state sensor (40), and a power source (10), the operation state sensor (40) being configured to measure continuously an operation state of the compressor (100), the power source comprising a neutral terminal and a phase terminal, the thermostat (30) comprising a first terminal and a second terminal, and the electronic control (50) comprising a phase feed input and a neutral feed input, wherein the neutral terminal of the power source (10) is electrically connected to the neutral feed input of the electronic control (50), and the phase terminal of the power source (10) is electrically connected to the first terminal of the thermostat (30), the second terminal of the thermostat (30) being electrically connected to the phase feed input of the electronic control (50), the thermostat (30) being configured to feed and un-feed selectively the electronic control (50), the electronic control (50) activating and deactivating selectively the compressor (100) and controlling its cooling capacity, the electronic control (50) being configured to calculate continuously the cooling capacity of the compressor (100), according to the signals of said at least one operation state sensor (40) and to alter continuously the operation rotation of the compressor (100) according to the cooling capacity calculated continuously.

2. The system according to claim 1, wherein the thermostat is of the electromechanical type.

3. The system according to claim 1, wherein that the thermostat is of the electronic type.

4. The system according to claim 1, wherein the thermostat (30) is configured to measure continuously the operation temperature (T.sub.oper) in the cooled environment (200).

5. The system according to claim 4, wherein the thermostat (30) is activated when the operation temperature (T.sub.oper) in the cooled environment (200) reaches a maximum limit (T.sub.max) defined by the thermostat (30) and deactivated when the operation temperature (T.sub.oper) in the cooled environment (200) reaches a minimum limit of cooling temperature (T.sub.min) defined by the thermostat (30).

6. The system according to claim 5, wherein the electronic control (50) is selectively fed and un-fed by activating and deactivating the thermostat (30).

7. The system according to claim 6, wherein the electronic control (50) activates the compressor (100) and controls its cooling capacity, while the thermostat (30) is activated.

8. The system according to claim 7, wherein the cooling capacity of the compressor (100) continues to be controlled by the electronic control (50) until the thermostat (30) is deactivated.

9. The system according to claim 1, wherein the electronic control (50) comprises a frequency inverter.

10. The system according to claim 9, wherein the compressor (100) is activated at an initial operation rotation by the electronic control (50), when the thermostat (30) is activated.

11. The system according to claim 10, wherein the initial operation rotation produces an initial operation torque sufficient to overcome the inertia of the compressor (100).

12. The system according to claim 11, wherein said at least one operation state sensor (40) is selected from the group comprising: current sensor, torque sensor, power sensor, time sensor, rotation sensor, or a combination of any thereof.

13. A method of feeding and controlling a variable capacity compressor (100) in a cooled environment (200), said variable capacity compressor activated electrically by an electronic control (50), the cooling environment (200) comprising a thermostat (30) configured to measure continuously the operation temperature (T.sub.oper) in the cooled environment (200), wherein said method comprises: activating the thermostat (30) when the operation temperature (T.sub.oper) in the cooled environment (200) reaches a maximum of cooling temperature (T.sub.max) defined by the thermostat (30); deactivating the thermostat (30) when the operation temperature (T.sub.oper) in the cooled environment (200) reaches a minimum cooling temperature (T.sub.min) defined by the thermostat (30); connecting electrically a phase feed input of the electronic control (50) to the thermostat (50) and connecting electrically a neutral feed input of the electronic control (50) to a neutral terminal of a power source (10); connecting electrically the thermostat (30) to a phase terminal of the power source (10); feeding the electronic control (50) when the thermostat (30) is activated; activating and controlling the cooling capacity of the compressor (100) by means of the electronic control (50) if the thermostat (30) is activated; un-feeding the electronic control (50) when the thermostat (30) is deactivated; and deactivating the compressor (100) when the thermostat (30) is deactivated; measuring continuously, by means of a torque sensor (40), the operation torque of the compressor (100); sending continuously signals from the torque sensor (40) to the electronic control (50); calculating continuously the cooling capacity of the compressor (100), according to the signals from the torque sensor (40); altering continuously the operation rotation of the compressor (100) according to the cooling capacity calculated continuously.

14. The method according to claim 13, wherein the compressor (100) is activated at an initial operation rotation by the electronic control (50) when the thermostat (30) is activated.

15. The method according to claim 14, wherein the initial operation rotation produces an initial operation torque sufficient to overcome the initial inertia of the compressor (100).

16. A variable capacity compressor (100) in a cooled environment (200), activated electrically by an electronic control (50), the electronic control (50) being connected electrically to a thermostat (30) arranged in the cooled environment (200) and to at least one operation state sensor (40), the thermostat (30) being configured to measure continuously an operation temperature (T.sub.oper) in the cooled environment (200), the thermostat (30) being activated when the operation temperature (T.sub.oper) in the cooled environment reaches a maximum limit of cooling temperature (T.sub.max) defined by the thermostat (30), the thermostat (30) being deactivated when the operation temperature (T.sub.oper) in the cooled environment (200) reaches a minimum limit of cooling temperature (T.sub.min) defined by the thermostat (30), wherein a phase feed input of the electronic control (50) is electrically connected to the thermostat (30) and a neutral feed input of the electronic control (50) is electrically connected to a neutral terminal of a power source (10), the thermostat (30) being electrically connected to a phase terminal of the power source (10), the compressor (100) configured to be: activated and have its cooling capacity controlled by the electronic control (50) when the thermostat (30) is activated so that the electronic control (50) is fed; and deactivated when the thermostat (30) is deactivated so that the electronic control (50) is un-fed, the operation state sensor (40) being configured to continuously measure the operation torque of the compressor (100), the electronic control (50) being configured to continuously receive signals from the operation state sensor (40), calculating continuously the cooling capacity of the compressor (100), according to the signals from the torque sensor (40) and altering continuously the operation rotation of the compressor (100) according to the cooling capacity calculated continuously.

17. A cooler (200) comprising a variable capacity compressor (100) activated electrically by an electronic control (50), the cooler (200) comprising a thermostat (30), the electronic control (50) being connected electrically to the thermostat (30) and to at least one operation state sensor (40), the thermostat (30) configured to measure continuously an operation temperature (T.sub.oper) in the cooler (200), the thermostat (30) being activated when the operation temperature (T.sub.oper) in the cooler (200) reaches a maximum limit of cooling temperature (T.sub.max) defined by the thermostat (30), the thermostat (30) being deactivated when the operation temperature (T.sub.oper) in the cooler (200) reaches a minimum limit of cooling temperature (T.sub.min) defined by the thermostat (30), the thermostat (30) being electrically connected to the electronic control (50), wherein the thermostat (30) is electrically connected to a phase input of the electronic control (50) and to a phase terminal of a power source (10), a neutral terminal of the power source (10) being electrically connected to a neutral input of the electronic control (50), the cooler (20) having its operation temperature (T.sub.oper) altered, according to the activation and deactivation of the thermostat (30), the thermostat (30) activating and deactivating selectively the compressor (100), such that: when the thermostat (30) is activated, the electronic control (50) is fed, the electronic control (50) activating and controlling the cooling capacity of the compressor (100), so that the operation temperature (T.sub.oper) of the cooler (200) will be reduced until the minimum limit of cooling temperature (T.sub.min) defined by the thermostat (30); and when the thermostat (30) is deactivated, the electronic control (50) is deactivated, the electronic control (50) deactivating the compressor (100), the operation state sensor (40) being configured to continuously measure the operation torque of the compressor (100), the electronic control (50) being configured to continuously receive signals from the operation state sensor (40), calculating continuously the cooling capacity of the compressor (100), according to the signals from the torque sensor (40) and altering continuously the operation rotation of the compressor (100) according to the cooling capacity calculated continuously.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present invention will now be described in greater detail with reference to an example of embodiment represented in the drawings. The figures show:

(2) FIG. 1 illustrates a prior-art solution to use a simple thermostat of the electromechanical type in cooling systems that make use of variable capacity compressors;

(3) FIG. 2A illustrates the alterations in the connections and removals of circuits and wires for connecting the electronic control, the simple thermostat of the electromechanical type, the power source and the variable capacity compressor;

(4) FIGS. 2B and 3 illustrates a preferred embodiment of the new connections between the electronic control, the simple thermostat of the electromechanical type, the power source and the variable capacity compressor, according to the teachings of the present invention; and

(5) FIG. 4 illustrates a cooler comprising an electronic control, a simple thermostat of the electromechanical type, a power source and a variable capacity compressor connected in accordance to the teachings of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

(6) As pointed out before, FIG. 1 illustrates the prior art of a solution to make use of simple thermostat of the electromechanical type in cooling systems with variable capacity compressors. As pointed out before, in order to overcome the deficiencies and problems of this solution, the present invention has been developed.

(7) FIG. 2A illustrates the alterations in the connections and removals of circuits, and wires for connecting the electronic control 50, thermostat 30, power source 10 and variable capacity compressor 100. One observes that a wire of the thermostat 30 for the electronic control 50 is removed, the tap 60 of the phase wire of the power source 10 for phase input of the electronic control is removed and the internal circuit for receiving signals from the thermostat 52 is removed in the present invention.

(8) FIGS. 2B and 3 illustrate a preferred embodiment of the new connections between the electronic control 50, the thermostat 30, the power source 10 and the variable capacity compressor 100 of the present invention.

(9) One observes that FIG. 4 illustrates a system for feeding and controlling a variable capacity compressor 100 comprising an electronic control 50, a thermostat 30 and a power source 10, such a system being used for controlling the cooling in a cooled environment 200.

(10) In a preferred embodiment, the cooled environment 200 may be a household refrigerator or a commercial one. Obviously, this is only a preferred embodiment, so that any cooled environment 200 that makes use of a system with a thermostat can be used with the present invention.

(11) The variable capacity compressor 100 of the present invention has, as a characteristic, the capability of adjusting the cooling capacity by varying the velocity of pumping cooling gas, that is, its mass flow, according to the need of the system and its demand for cooling. The variation in the mass flow takes place from a minimum value to a maximum value, this range of values being proportional to the rotation of the electric motor that drives the variable capacity compressor. The variation in the rotation is achieved, on these compressors, by means of the electronic control 50.

(12) In a preferred embodiment, the variable capacity compressor 100 is driven by electric motors of single-phase, two-phase or three-phase direct current, depending on the type of application. Moreover, the compressor 100 comprises at least three connections for receiving feed signals from the electronic control 50. It should be noted that the number of connections depends upon the type of electric motor used (single-phase, two-phase or three-phase). The compressor 100 further comprises intake valves 101 and 102, which are, respectively, fluidly connected to the evaporator 201 and to the condenser 202 of the cooled environment 200, preferably of the cooler.

(13) With regard to the electronic control 50, preferably it is a frequency inverter provided with a number of electronic circuits with different functions, as for example, a power circuit with input stage for filtering electromagnetic interference and a rectifying-bridge stage for converting alternating voltage from an external power source to a direct voltage, a control circuit (microcontroller or DSPDigital Signal Processor), an auxiliary power source for generating the internal voltages for other circuits or components of the inverter, a circuit formed by power semiconductors for activating the electric motor employed on the compressor, among others.

(14) The electronic control 50 is used for controlling the voltage and the frequency applied to the compressor 100, thus varying the velocity of pumping cooling gas, that is, the mass flow thereof, according to the need of the system and its demand for cooling.

(15) In a preferred embodiment of the present invention, the electronic control 500 comprises a phase feed input, a neutral feed input and at least three connections 51a-c for sending feed signals to the compressor 100. It should be observed that the number of connections depends on the type of electric motor used (single-phase, two-phase or three-phase).

(16) The thermostat 30 of the present invention is simple, of the electromechanical type that makes use of a combination of a bulb containing a fluid that expands with the rise in temperature, installed so as to be exposed to the temperature inside the cooled environment, and mechanically connected to an electromechanical switch, sensitive to this expansion and contraction of the fluid present inside the bulb, being capable of turning on and off the switch at predetermined temperatures, according to the application. This switch interrupts the current supplied to the compressor, controlling its operation, keeping the internal environment of the cooling system within pre-established limits of temperature.

(17) It should be pointed out that other types of thermostat or devices might be used instead of the electromechanical type, as long as they have only the function of monitoring the temperature and switching to activate the compressor 100. For instance, electronic thermostats with relay output might be used instead of the electromechanical thermostat. In other words, thermostats or devices with the function of controlling the compressor 100 having the same function of the inverter are not part of the scope of the present invention.

(18) In a preferred embodiment of the present invention, the thermostat 30 comprises a first terminal, a second terminal and a bulb configured to measure an operation temperature T.sub.oper in the cooled environment 200. Further preferably, one observes that the thermostat 30 is arranged inside the cooled environment 200, especially inside the cooler.

(19) The power source 10 is a source of alternating current of 127V or 220V, depending on the type of motor used for driving the variable capacity compressor 100. The power source 10 comprises a neutral terminal and a phase terminal.

(20) The components of the system of the present invention having been described, the electric and fluid connections thereof are described hereinafter.

(21) In the system of the present invention, the neutral terminal of the power source 10 is electrically connected to the neutral feed input of the electronic control 50 and the phase terminal of the power source 10 is electrically connected to the first terminal of the thermostat 30, the second terminal of the thermostat 30 is electrically connected to the phase feed input of the electronic control 50.

(22) Considering that the thermostat 30 is arranged inside the cooling environment 200, one observes that the latter will measure continuously the operation temperature T.sub.oper in the cooled environment 200.

(23) During the measuring process, the thermostat 30 can be activated and deactivated according to the variation in operation temperature T.sub.oper within the cooled environment 200. By activating and deactivating one means the action of the thermostat 30 to close or open its contact, according to the expansion and contraction of the bulb.

(24) More specifically, the thermostat 30 is activated when the operation temperature T.sub.oper in the cooled environment 200 reaches a maximum cooling temperature T.sub.max defined by the thermostat 30 and deactivated when the operation temperature T.sub.oper in the cooled environment 200 reaches a minimum limit of cooling temperature T.sub.min defined by the thermostat 30.

(25) In general, the user can define which temperature is suitable for the cooled environment 200, especially in a cooler. For instance, the thermostat 30 may have a turning button with steps, which the user can turn and select the desired temperature. Alternatively, the temperature may be selected by the user digitally on the thermostat 30.

(26) Depending on the state of the thermostat 30, that is, whether it is or is not activated, the latter can selectively feed and un-feed the electronic control 50. With the feeding and un-feeding of the electronic control 50, the latter is capable of selectively activating the compressor 100 and controlling its cooling capacity or deactivate the compressor 100.

(27) When the thermostat 30 is activated, the electronic control 50 is fed so as to activate the compressor 100 and control its cooling capacity. It should be noted that the cooling capacity of the compressor 100 continues to be controlled by the electronic controller 50, until the thermostat 30 is deactivated. In other words, the compressor 100 continues to be controlled by the electronic control 50, while the operation temperature T.sub.oper does not reach the minimum limit of cooling temperature T.sub.min defined by the thermostat 30.

(28) In an opposite way, when the thermostat 30 is deactivated, the electronic control 50 is un-fed, so as to deactivate the compressor 100. When both the electronic control 50 and the compressor 100 are off, the system does not consume any energy, thus preventing unnecessary expenditure of energy with stand-by consumption, as happens in the prior-art systems. It should be pointed out that the compressor 100 is kept deactivated, while the operation temperature T.sub.oper in the cooled environment 200 does not reach the maximum limit of cooling temperature T.sub.max.

(29) The control of cooling and operation temperature T.sub.oper takes place in real time through the electronic control 50, without the need for additional circuits or memories, for collecting data from preceding circuits. Such a control takes place by activating the compressor 100 at an initial operation rotation by the electronic control 50. When the thermostat 30 is activated, the initial operation rotation produces an initial operation torque sufficient to overcome the inertia of the compressor 100.

(30) In order for the control to be carried out, at least one operation state sensor 40 is used for measuring continuously the operation state of the compressor 100. Said at least one operation state sensor 40 is at least one sensor selected from a group consisting of: current sensor, torque sensor, power sensor, time sensor, rotation sensor, or the combination of any thereof.

(31) The signals generated continuously by said at least one operation state sensor 40 are then continuously sent to the electronic control 50. The latter, in turn, carrying out a derivation of the signals and then calculates the cooling capacity of the compressor 100 and the power to be applied to the compressor 100 to reach such capacity.

(32) It should be pointed out that the cooling capacity of the compressor 100 is calculated continuously from the signals from said at least one operation state sensor 40. On the basis of the cooling capacities of the compressor 100 calculated continuously, the electronic control 50 is configured to alter continuously the operation rotation of the compressor 100, applying a higher or lower power for controlling the compressor 100.

(33) As pointed out before, the present invention brings a number of advantages over the prior art, like reduction in waste or energy by keeping the electronic control 50 constantly fed, reduction of costs with circuits, optocouplers, volatile memories, wires, reduction of costs with mounting operation and in contour conditions such as test on the client's line, increase in the production efficiency, among others.

(34) A preferred example of embodiment having been described, one should understand that the scope of the present invention encompasses other possible variations, being limited only by the contents of the accompanying claims, which include the possible equivalents.