DIGITAL REFRIGERATION CONTROLLER WITH INTEGRATED MODULE DRIVEN ELECTRONIC EXPANSION VALVE

Abstract

A digital refrigeration controller (100) with integrated module driven Step Motor Electronic Expansion Valve. The digital refrigeration controller (100) comprises a System (200) with a Processing Unit (206) for management of the digital controller (100), Unit (206) being connected to Serial Communication Interface (202), Sensor Signal Conditioning System (203), Charge Control System (204), Human-Machine Interface (205), Power Supply Detection and Selection System (207), Backup Power Supply Charging System (208), Real Time Clock (209) and Step Motor Electronic Expansion Valve Drive System (210). System (200) comprises further the following elements: Power Supply (201), a Backup Power Supply (211) and a Current Monitor (212). In case of power outage, the different elements of the system interact to keep the step motor electronic expansion valve closed without the need of external modules.

Claims

1. A digital refrigeration controller with integrated module driven Electronic Expansion Valve, said digital controller (100) being provided with a non-volatile memory and characterized in that it is provided with an onboard System (200) comprising the following elements: a) a Processing Unit (206) for the management of the digital refrigeration controller (100) through the execution of pre-scheduled and stored instructions in a non-volatile electronic memory, said Unit being connected to the following elements: a1) a Serial Communication Interface (202) for interfacing and remote operation control; a2) a Sensor Signal Conditioning System (203) for conditioning the sensors signals into a standard compatible with the electrical standard of said Processing Unit (206); a3) a Charge Control System (204) to keep the suitable power charge level in a Backup Power Supply Charging System (208); a4) a Human-Machine Interface (205); a5) a Power Supply Detection and Selection System (207) to enable the refrigeration controller (100) to continue operating even in case of power outage; a6) a Backup Power Supply Charging System (208) to keep sufficient energy for the closure of the electronic valve in case power outage; a7) a Real Time Clock (209) for creating defrosting events scheduling and entry in economy mode; and a8) a Step Motor Electronic Expansion Valve Drive System (210); b) A Power Supply (201), said Supply (201) being connected to Charge Control System (204), Power Supply Detection and Selection System (207) and Sensor Signal Conditioning System (203); c) A Backup Power Supply (211) to keep the refrigeration controller (100) working until the complete closure of the electronic valve, connected to Power Supply Detection and Selection System (207) and to Backup Power Supply Charging System (208); and d) A Current Monitor (212) for feedback into said refrigeration controller (100) of the electronic expansion valve operating Status.

2. The digital refrigeration controller according to claim 1, characterized in that Sensor Signal Conditioning System (203) creates a refrigerant fluid retreat function (Pump-down).

3. The digital refrigeration controller according to claim 1, characterized in that Power Supply Detection and Selection System (207) is further connected to Power Supply (201), Step Motor Electronic Expansion Valve Drive System (210), Backup Power Supply (211) and Current Monitor (212).

4. The digital refrigeration controller according to claim 1, characterized in that, when in service, upon a power outage being detected by Power Supply Detection and Selection System (207): a) said Power Supply Detection and Selection System (207) signalizes to Processing Unit (206) and also commutes Backup Power Supply (211); b) the signal received by said Power Supply Detection and Selection System (207) by Processing Unit (206) starts the expansion valve closure by means of Step Motor Electronic Expansion Valve Drive System (210) where Current Monitor (212) implements the Status feedback; c) Backup Power Supply (211) commuted by Power Supply Detection and Selection System (207) receives power stored in Backup Power Supply Charging System (208) previously charged by Charge Control System (204); and d) Power Supply Detection and Selection System (207) implements the commutation of Backup Power Supply (211) while the interaction between Power Supply (201), Charge Control System (204) and Backup Power Supply Charging System (208) secures that Backup Power Supply (211) works whenever required.

5. The digital refrigeration controller according to claim 1, characterized in that the outer rear portion of said integrated module comprises sensor S1 connected between (111) and (112), sensor S2 connected between (113) and (114), sensor S3 connected between (115) and (116), and sensor P1 connected between (123) and (124).

6. The digital refrigeration controller according to claim 5, characterized in that the outer rear portion of said integrated module comprises further the power supply of the digital refrigeration controller (100) between (121) and (122), a digital input between (117) and (118), and between (119) and (120) a serial communication port.

7. The digital refrigeration controller according to claim 5, characterized in that the outer rear portion of said module comprises further the Step Motor Electronic Expansion Valve connection between (126) up to (130).

8. The digital refrigeration controller according to claim 5, characterized in that the outer rear portion of said integrated module comprises further the compressor (132) output, the ventilator (133) output, the defrost output (134) the lamp (135) or auxiliary (135) output and at (131) the common terminal

9. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 is a simplified scheme of a state-of-the-art refrigeration controller system, with individual, separated modules.

[0035] FIG. 2 is a schematic illustration of the front portion of the equipment for refrigeration control employing the inventive system.

[0036] FIG. 3 is a schematic illustration of the rear portion of the equipment for refrigeration control employing the inventive system.

[0037] FIG. 4 is a simplified flowsheet of the compact, single-module integrated system for refrigeration control employing the inventive system.

DETAILED DESCRIPTION OF THE INVENTION

[0038] According to the invention, the expression integrated module or single module means that all of the elements which compose the control system of the present controller are contained in a single housing, in opposition to state-of-the-art controllers which employ several coupled modules by means of electrical connections and linkages, both plastic and metallic.

[0039] Still in accordance with the invention, the expression step motor expansion electronic valve encompasses both the unipolar and the bipolar step motor.

[0040] Still in accordance with the invention, in the present specification, claims and abstract, the expression controller is equivalent to the expressions digital refrigeration controller or digital controller or still, refrigeration controller.

[0041] The invention comprises, therefore, a digital refrigeration controller where, contrary to the state-of-the-art controllers comprising several modules, the electronic expansion valve superheat control is provided by a system contained in one single module.

[0042] The invention will be described below by reference to the attached Figures.

[0043] Thus, FIG. 2 shows the front view of controller (100) with the elements of the Human-Machine Interface (205) (see FIG. 4), namely, key (101) to access the so-called facilitated menu, where a set of easy access parameters is available to the user. By pressing key (101) it is possible to navigate through the facilitated menu and by pressing key (102) it is possible to select the desired menu option, keys (103) and (104) enabling the increment and decrement of the parameter seen on the front display. LED (110) informs the status of compressor (132) output, LED (109) informs the output status of ventilator (133), LED (108) informs the defrost output (134) status, LED (107) informs the lamp (135) or auxiliary (135) output status, LED (106) informs the modulation process of the step motor electronic expansion valve and LED (105) informs the scale utilized by the controller in degrees Celsius or Fahrenheit.

[0044] FIG. 3 shows the rear view of the digital refrigeration controller (100) where the connector with reference numerals from (111) to (130) is intended for connections with sensors, power source, serial communication and connection with the step motor electronic expansion valve. The connector with reference numerals from (131) to (135) is intended for power connections.

[0045] The temperature sensor for the power measured in the refrigeration process referred to as S1 is connected between (111) and (112), the sensor for the current temperature measured in the evaporator referred to as S2 is connected between (113) and (114), the sensor for current temperature measured at the compressor suction port referred to as S3 is connected between (115) and (116), and the sensor for suction pressure of the refrigerant fluid in the compressor, referred to as P1 is connected between (123) e (124). These sensors are those mentioned in the Sensor Signal Conditioning System (203) element of FIG. 4.

[0046] The power supply of the digital refrigeration controller (100) is performed between (121) and (122), between (117) and (118) a digital input is present, and between (119) and (120) there is a serial communication port.

[0047] The step motor electronic expansion valve (not represented) is connected between (126) up to (130).

[0048] Still in FIG. 3, the compressor (132) output, the ventilator (133) output, the defrost output (134) the lamp (135) or auxiliary (135) output and at (131) the common terminal can be observed.

[0049] On the other hand, FIG. 4 is a flowsheet of system (200) internal elements for the control of refrigeration and superheat degree of the refrigerant fluid and their logical and functional interactions to create the digital refrigeration controller (100).

[0050] In System (200), a Human-Machine Interface (205) is provided with access keys for navigating the controller program and increment/decrement of the parameters programmed in a non-volatile inner memory, as well as a LED display for viewing the process parameters and messages to the user. These elements have been described by reference to FIG. 2.

[0051] The elements which form System (200) of the inventive digital refrigeration controller (100) are commercially available and will be described in detail below in the present specification.

[0052] System (200) for superheat control of the digital refrigeration controller (100) refrigerant fluid comprises, in a single module, the following elements:

[0053] A Main Power Source (201) to provide suitable power levels to the internal elements of System (200), connected between (121) and (122) (see FIG. 3) with 12V voltage under direct current. A Power Source (201) useful for the purposes of the invention comprises voltage regulating semiconductor integrated circuits, providing suitable levels of electrical potential for polarization of System (200) elements.

[0054] A Serial Communication (202) Interface by serial communication standard RS485 for interfacing and remote-control operation. This kind of interface is useful for the purposes of the invention since it enables the reception of operation commands, reception of recipes and scheduling of events, reading and writing of the function parameters saved in a non-volatile electronic memory, and monitoring of the Sensor Signal Conditioning System (203) measurements.

[0055] A Sensor Signal Conditioning System (203) to condition the sensor signals into a standard compatible with the Processing Unit (206) electrical standard. A Sensor Signal Conditioning System (203) useful for the purposes of the invention comprises an arrangement of sensors and capacitors disposed as attenuation and signal filtering networks for conditioning sensor signals at power levels suitable for the Processing Unit (206) working.

[0056] A Power Control System (204) for maintaining the power level suitable to the Emergency Energy storage system (208). System (204) is useful for the purposes of the invention since it secures through the use of semiconductor transistors a minimum level of stored energy, besides protection against overloads, securing safety.

[0057] A Human-Machine (205) Interface provided with keys and a LED display. Interface (205) is useful for the purposes of the invention since it enables the user to have facilitated access to the function menu and instant visualization of the refrigeration process measurements.

[0058] A Processing Unit (206), also called onboard processing unit, which manages all the controller (100). Unit (206) is useful for the purposes of the invention since it is able to execute instructions which have been pre-programmed and stored in a non-volatile electronic memory, making it possible to develop control, supervision and data communication algorithms.

[0059] A Power Source Detection and Selection System (207) enabling the digital refrigeration controller (100) to operate even in case of power outage. A Power Source Detection and Selection System (207) useful for the purposes of the invention comprises an electronic voltage comparator to signalize the occurrence of power shortage at the Main Power Source (201) securing quick commutation towards Emergency Power Source (211).

[0060] An Emergency Power Storage System (208) able to keep sufficient energy for the closure of the electronic valve (not represented) in case of power shortage or drop. An Emergency Power Backup System (208) useful for the purposes of the invention comprises a solid-state element having electrical properties of electrostatic energy storage.

[0061] A Real Time Clock (209) able to synchronize the digital refrigeration controller (100). A Real Time Clock (209) useful for the purposes of the invention comprises a specific integrated circuit having data interface with Processing Unit (206) thus enabling the creation of defrosting events scheduling and entry in economy mode.

[0062] A Drive System (210) for the Step Motor Electronic Expansion Valve enabling the digital refrigeration controller (100) to perform the superheat degree control. A Step Motor Electronic Expansion Valve Drive System (210) useful for the purposes of the invention comprises semiconductor switches and enables the digital refrigeration controller (100) to control at the same time the refrigeration and superheat functions.

[0063] An Emergency Power Source (211) able to secure the digital refrigeration controller (100) working until the complete closure of the electronic valve (not represented). An Emergency Power Source (211) useful for the purposes of the invention comprises a voltage lifting solid-state switch mode converter and secures the digital refrigeration controller (100) working during the period at which the expansion valve (not represented) closure is mandatory due to power outage.

[0064] A Current Monitor (212) for providing feedback into the digital refrigeration controller (100) on the expansion valve (not represented) operating status. A Current Monitor (212) is useful for the purposes of the invention since it provides feedback, which enables the digital refrigeration controller (100) to be aware of the expansion valve (not represented) operating status, improving the operating safety of the refrigeration process, since operation alarms can be triggered.

[0065] The digital refrigeration controller (100) working System (200) for the control of the superheat of the refrigerant fluid will be described below.

[0066] The onboard Processing Unit (206) communicates with serial communication Interface (202), Human-Machine Interface (205), Real Time Clock (209) and Step Motor Electronic Expansion Valve Drive System (210).

[0067] The communication of onboard Processing Unit (206) with Real Time Clock (209) enables the creation of a digital defrosting planner besides the planner of the so-called economy mode, referring to events of scheduled alteration in the adjustment set-point of the refrigeration process at low demand hours, enabling power savings. The power savings obtained by the system of the invention is higher than that of state-of-the-art systems, since the energy consumption of additional modules is cancelled.

[0068] The onboard Processing Unit (206) communicates further with Serial Communication Interface (202), and with Sensor Signal Conditioning System (203). These sensors have been mentioned in the description of FIG. 3, being referred to as S1 for the power measured in the refrigeration process, S2 for the current temperature measured in the evaporator, S3 for current temperature measured at the compression suction port, and P1 for suction pressure of the refrigerant fluid in the compressor. These sensors provide feedback signals for the PID algorithm, digitally implemented in Unit (206) which by means of its connections with Serial Communication interface (202), Human-Machine Interface (205), Clock (209) and System (210) secures responsive control since its direct connection is not subject to network traffic.

[0069] According to the invention, by measuring the refrigerant fluid pressure Sensor Signal Conditioning System (203) enables the creation of a refrigerant fluid retreat functionpump-down. In state-of-the-art systems this work is usually performed by external equipment to the controller, adding volume to the setup and further equipment acquisition cost. Additionally, the adjustment of this function becomes more complex and less practical, since the extra equipment traditionally does not communicate with the process controller, requiring thus manual adjustment subject to human failure.

[0070] Still according to the invention, the pressure measurement, when converted into saturated temperature, enables the creation of protection against low evaporation temperature (LOP) and high evaporation temperature (MOP). Such protections work for extreme operation situations, typically transitory events when high-intensity thermal loads are requested. Such situations can compromise the compressor operating useful life in the refrigeration system, since it will require more electromechanical effort at the transitory condition.

[0071] The onboard Processing Unit (206) provides digital switching signals of frequency and amplitude such that when applied to Step Motor Electronic Expansion Valve Drive System (210), the same command the required modulation to maintain the superheat degree. Advantageously, in the invention, the integration between said elements (206) and (210) renders the response to the control more agile by facilitating the information exchange on measurements and control signals at high data rates, since they are in the same module, eliminating the network traffic conflict.

[0072] Still, the referred to onboard Processing Unit (206) together with Current Monitor (212) enables to obtain the valve status, with the possibility to determine if it is operational or not. Advantageously, this functionality widens the working safety of the refrigeration facility, since it creates operating alarms for the refrigeration plant technical responsible staff, reducing the possibility of equipment damage. This relevant functionality is not described nor suggested in state-of-the-art technique systems.

[0073] As can be seen in FIG. 4 flowsheet, a Power Source Detection and Selection System (207) continuously monitors the electrical voltage supplied by Main Power Source (201); in case it fails due to power shortage, Emergency Power Source (211) is actuated and receives power stored in the Emergency Power Backup System (208).

[0074] The Emergency Power Backup System (208) is managed by Control Power System (204) securing that the stored power will be sufficient for the needs of the step motor electronic expansion valve emergency closure in case of power outage, providing competitive advantage to the present invention before the state-of-the-art technique, since the need of external module for power supply in case of power shortage is eliminated.

[0075] The logical and physical connection between Main Power Source (201), Power Control (204), Processing Unit (206), Detection and Selection Source System (207), Emergency Power Backup System (208), Step Motor Electronic Expansion Valve Drive System (210), Emergency Power Source (211) and Current Monitor (212) of System (200) render the digital refrigeration controller (100) able to deal with power outage events and even so secure the emergency closure of the Step Motor Electronic Expansion Valve (not represented).

[0076] When in service, the interaction between the various elements of system (200) to control the refrigerant fluid superheat whenever a power outage is detected will be described below.

[0077] System (200), whenever a power outage by Power Source Detection and Selection System (207) is detected: [0078] a) said Power Source Detection and Selection System (207) signalizes to Processing Unit (206) and also commutes Emergency Power Source (211); [0079] b) the signal received by said Power Source Detection and Selection System (207) by Processing Unit (206) starts the expansion valve closure by means of Step Motor Electronic Expansion Valve Drive System (210) where Current Monitor (212) implements the Status feedback; [0080] c) Emergency Power Source (211) commuted by Power Source Detection and Selection System (207) receives power stored in the Emergency Power Backup System (208) previously loaded by Charge Control System (204); and [0081] d) Power Source Detection and Selection System (207) implements the Emergency Power Source (211) commutation while the interaction between Main Power Source (201), Charge Control System (204) and Emergency Power Backup System (208) secures that Emergency Source (211) works whenever required.

[0082] The previous description related to the digital refrigeration controller (100) and the relationships among the several elements comprising the onboard control system (200) is additionally detailed below: [0083] a) A Processing Unit (206) for the management of the digital refrigeration controller (100) through the execution of pre-scheduled and stored instructions in a non-volatile electronic memory, said Unit being connected to the following elements: [0084] a1) a Serial Communication Interface (202) for interfacing and remote operation control; [0085] a2) a Sensor Signal Conditioning System (203) for conditioning the sensors signals into a standard compatible with the electrical standard of said Processing Unit (206); [0086] a3) a Charge Control System (204) to keep the suitable power load level in Emergency Power Backup System (208); [0087] a4) a Human-Machine Interface (205); [0088] a5) a Power Source Detection and Selection System (207) to enable the refrigeration controller (100) to continue operating even in case of power outage; [0089] a6) an Emergency Power Backup System (208) to keep sufficient energy for the closure of the electronic valve in case of power outage; [0090] a7) a Real Time Clock (209) for creating defrosting events scheduling and entry in economy mode; and [0091] a8) a Step Motor Electronic Expansion Valve Drive System (210); b) A Main Power Source (201), said Power Source (201) being connected to the Charge Control System (204), to Power Source Detection and Selection System (207) and to Sensor Signal Conditioning System (203); [0092] c) An Emergency Power Source (211) to keep refrigeration controller (100) working until the complete closure of the electronic valve, connected to the Power Source Detection and Selection System (207) and to Emergency Power Backup System (208); and [0093] d) A Current Monitor (212) for feedback into said refrigeration controller (100) of the electronic expansion valve operating Status.

[0094] Further, it is possible to configure the digital refrigeration controller (100) of the invention to operate only in the Driver function, where the functions and logics of refrigeration are disabled and it works just to drive the step motor electronic expansion valve and superheat degree with PID feed back.

[0095] Further, the digital refrigeration controller (100) is provided with protection functions integrated to preserve the compressor from low superheat events (LoSH), low evaporation temperature (LOP) and high evaporation temperature (MOP), adding parameters to set forth the conditions for alarms and reactions to same. Such protection from low superheat events (LoSH) works in transitory events of high thermal load alteration, acting to hinder the return of liquid state refrigerant fluid to the compressor.

[0096] Thus, the provided technological novelty is an advancement to the state-of-the-art technique in that it comprises a digital refrigeration controller (100) complete and integrated to be disposed in a cabinet door or electrical panel command, making it easier the installation and operation of plants and industrial and commercial refrigeration processes by integrating a huge set of systems in a single, compact controller, arranged in a single module.

[0097] Such systems are currently disposed in individual modules, such as can be schematically seen in the block diagram of FIG. 1, where the control element (302) is external, connected by wires to electronic expansion valve (301) driver (303), powered by external carrier (304) acting on electronic valve (301). These state-of-the-art systems hinder the adjustment and parametrization process of the functions, since their elements are physically separated, without logic communication among them. In this sense the invention provides new operating and competitive advantages by enabling Processing Unit (206) to control the several above-mentioned functions while the interaction among elements of System (200) integrated to digital refrigeration controller (100) results in a less complex installation.

[0098] Thus, in spite of the fact that the elements which comprise the arrangement of System (200) for control of the digital refrigeration controller (100) are commercially available, the present invention is not only new, since there is no known single-module, similar equipment to perform the desired control function, but also inventive, since it incorporates logical communication among the various elements to obtain not described nor suggested results in state-of-the-art technique, making it easier the functions adjustment and parametrization process, while at the same time the installation complexity is reduced.

[0099] Advantageously, the invention, by considering the reduction of inputs and raw materials as plastics, further extending to metals in the installation and production steps, objectively reduces such needs in accordance with the current environmental concerns. Such concern is of paramount importance nowadays, since Brazil is the 4th country in plastic waste production, see <https://www.wwforg.br/?70222/Brasil-e-o-4-pais-do-mundo-que-mais-gera-lixo-plastico>.