Electric valve control device

Abstract

To enable easy update of a control program.SOLUTION: A controller 1 includes: a control microcomputer 6 which controls opening / closing of an electronic expansion valve 24 using a control program 71 based on temperature data and pressure data, to control a degree of superheat of a refrigeration cycle system; and a communication circuit 2 which receives an update program 151 from the outside. The control microcomputer 6 holds the electronic expansion valve 24 in a fully closed state during updating the control program 71 to the update program 151.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a control device for an electric valve such as an electronic expansion valve, such as an overheat controller.

Background Art

[0002] Conventionally, a refrigeration device using an electronic expansion valve has been known. This type of refrigeration device obtains the difference (superheat degree) between the temperature on the outlet side and the temperature on the inlet side of the evaporator in the refrigeration cycle system of the refrigeration device, and according to the deviation between the measured value of this superheat degree and the set value (target value) of the superheat degree, for example, controls the opening degree of the electronic expansion valve by PID control (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] The control of an electric valve such as the above-described electronic expansion valve is often performed by a control program executed by a microcomputer or the like. And this type of control program may be updated due to function addition or defect correction.

[0005] However, the update of the control program in such a control device for an electric valve has been performed manually considering the timing when the system stops, etc., and it has been troublesome.

[0006] In order to save such trouble, it is conceivable to automatically update the control program, but depending on the state of the electric valve at the time of stop, there is a risk of affecting other devices such as the compressor constituting the refrigeration cycle system. Therefore, simply automatically updating when the system stops may not be sufficient in some cases.

[0007] Therefore, the present invention aims to enable easy updating of the control program without affecting other equipment that constitutes the refrigeration cycle system. [Means for solving the problem]

[0008] The invention made to solve the above problems comprises a control unit that controls the degree of superheating of a refrigeration cycle system by controlling the opening and closing of an electric valve by a control program based on temperature information, a receiving unit that receives a new control program from the outside, and an update unit that updates the control program to the new control program, wherein the control unit holds the electric valve in a predetermined state when the update unit is performing the update. [Effects of the Invention]

[0009] According to the present invention, by holding the electric valve in a predetermined state, the control program can be updated without affecting other equipment constituting the refrigeration cycle system, such as other devices, when updating the control program or restarting after its completion. [Brief explanation of the drawing]

[0010] [Figure 1] This figure shows an example of a refrigeration system that uses an electronic expansion valve as an electric valve according to one embodiment of the present invention. [Figure 2] Figure 1 is a schematic diagram of the system centered around the controller shown. [Figure 3] Figure 2 is a flowchart of the controller update operation. [Figure 4] Figure 2 is a flowchart of the controller update operation. [Figure 5] This figure shows a modified example of the EEPROM usage method shown in Figure 2. [Modes for carrying out the invention]

[0011] A superheat controller and an electric valve control circuit according to one embodiment of the present invention will be described. Figure 1 is a diagram showing an example of a refrigeration system that uses an electronic expansion valve as the electric valve according to this embodiment.

[0012] As shown in Figure 1, the cooling system consists of an evaporator 21 installed in the freezer 20, a compressor and condenser in the refrigerator 22, a feed solenoid valve 23 and an electronic expansion valve 24, all connected in a ring shape by piping to form a well-known refrigeration cycle.

[0013] In Figure 1, reference numeral 25 denotes an evaporator outlet temperature sensor that measures the temperature on the outlet side of the evaporator 21, reference numeral 26 denotes an evaporator inlet temperature sensor that measures the temperature on the inlet side of the evaporator 21, and reference numeral 27 denotes an inlet temperature sensor that measures the temperature inside the freezer 20. The measurement signals from these sensors are input to the controller 1.

[0014] Controller 1 includes a control unit such as a microcomputer, a drive circuit for the electronic expansion valve, memory, a display unit, and an operation unit. It calculates the difference (superheating degree) between the evaporator outlet temperature measured by the evaporator outlet temperature sensor 25 and the evaporator inlet temperature measured by the evaporator inlet temperature sensor 26, and outputs an operation signal to the electronic expansion valve 24 to control the opening degree of the electronic expansion valve 24 using PID control according to the deviation between the measured superheating degree and the set value (target value) of the superheating degree. Controller 1 is also called a superheating degree controller.

[0015] Figure 2 shows a schematic configuration diagram of the controller 1 shown in Figure 1. As shown in Figure 1, the controller 1 includes a communication circuit 2, a measurement circuit 3, a drive circuit 4, a contact detection circuit 5, a control microcontroller 6, and an EEPROM 7.

[0016] Communication circuit 2 communicates with the user PC 15, which will be described later, for example via serial communication. Communication circuit 2 then receives an updated version (new control program) of the control microcontroller 6 from the user PC 15 and outputs it to the control microcontroller 6. In other words, communication circuit 2 functions as a receiver that receives new control programs from an external source.

[0017] The measurement circuit 3 is connected to a temperature sensor 11 and a pressure sensor 12, which will be described later. The measurement circuit 3 outputs the signals input from the temperature sensor 11 and the pressure sensor 12 to the control microcomputer 6 as temperature data and pressure data.

[0018] The drive circuit 4 outputs a drive signal for driving the electronic expansion valve 24 based on an excitation signal or the like from the control microcomputer 6. The drive circuit 4 can be configured as, for example, a constant current chopper drive circuit.

[0019] The contact detection circuit 5 receives an operation instruction from a start input 13, which will be described later. That is, the contact detection circuit 5 functions as an input unit for receiving information regarding the operation instruction from a higher-level device. The contact detection circuit 5 outputs the input operation instruction to the control microcomputer 6. The operation instruction includes, for example, start and stop. When the operation instruction is "ON", it indicates start, and when the operation instruction is "OFF", it indicates stop.

[0020] The control microcomputer 6 is in charge of the overall control of the controller 1. The control microcomputer 6 generates an excitation signal for controlling the opening degree of the electronic expansion valve 24 based on the temperature data and pressure data input from the measurement circuit 3 and outputs it to the drive circuit 4. Further, the control microcomputer 6 performs the above-mentioned overall control and the driving of the electronic expansion valve 24, etc., according to the control program 71 stored in the EEPROM 7. That is, the control microcomputer 6 functions as a control unit for controlling the superheat degree of the refrigeration cycle system by controlling the opening and closing of the electric valve according to the control program 71 based on at least temperature information.

[0021] The EEPROM (Electrically Erasable Programmable Read Only Memory) 7 is a readable and writable non-volatile semiconductor memory and functions as a storage unit in which the control program 71 of the control microcomputer 6 is stored. In the configuration of FIG. 2, the EEPROM 7 is external to the control microcomputer 6. However, when a non-volatile memory is built into the control microcomputer 6, the control program 71 may be stored in the non-volatile memory.

[0022] The temperature sensor 11 is a general term for the evaporator outlet temperature sensor 25, the evaporator inlet temperature sensor 26, and the internal temperature sensor 27 shown in FIG. 1. The pressure sensor 12 is a sensor that detects the evaporation pressure on the outlet side of the evaporator 21. The start-up input 13 receives an operation instruction for the controller 1 output from the upper system 14 and outputs it to the controller 1.

[0023] The upper system 14 is a system that controls each device shown in FIG. 1, the refrigerator 22, etc. The upper system 14 is composed of, for example, a computer. The upper system 14 gives an operation instruction to the controller 1 via the start-up input 13.

[0024] The user PC 15 is, for example, a PC (personal computer) owned by a user, a maintenance worker, etc. The user PC 15 stores an update program (new control program) 151 of the control program 71 of the control microcomputer 6. By connecting to the controller 1, the control program 71 is updated via the communication circuit 2. Note that the update program 151 is an updated version of the control program 71 as described above.

[0025] Next, the update operation of the control program 71 in the controller 1 having the above-described configuration will be described with reference to the flowcharts of FIGS. 3 and 4. FIG. 3 is a flowchart when not referring to the operation instruction from the contact detection circuit 5. The flowcharts shown in FIGS. 3 and 4 are executed by the control microcomputer 6. Therefore, the control microcomputer 6 functions as an update unit that updates the control program to a new control program.

[0026] First, the control microcomputer 6 determines whether it is in the process of superheat control (step S101). That is, the control microcomputer 6 determines whether the opening degree of the electronic expansion valve 24 is currently being controlled.

[0027] If the result of the determination in step S101 is that overheating control is in progress (step S101: Yes), the control microcontroller 6 determines whether there is a request to update the control program 71 (step S102). The update request is input from the user PC 15 via the communication circuit 2.

[0028] Next, if the determination in step S102 indicates a request to update the control program 71 (step S102: Yes), the control microcontroller 6 stops the overheat control (step S103) and starts updating the control program 71 (step S104).

[0029] On the other hand, if the result of the determination in step S102 is that there is no request to update the control program 71 (step S102: No), the control microcontroller 6 continues the overheat control (step S105) and controls the opening degree of the electronic expansion valve 24 (step S106). In other words, since there is no request for an update, normal operation continues.

[0030] On the other hand, if the result of the determination in step S101 is that overheat control is not in progress (step S101: No), the control microcontroller 6 determines whether the control program 71 is being updated (step S107). In other words, it determines whether the update program 151 acquired via the communication circuit 2 is being stored in the EEPROM 7.

[0031] If the result of the determination in step S107 indicates that an update is in progress (step S107: Yes), the control microcontroller 6 continues the update (step S108). During this update, the opening of the electronic expansion valve 24 is set to fully closed (step S109). In other words, the control microcontroller 6 stops the electronic expansion valve 24 to maintain a predetermined state. The predetermined state is preferably a safe state for the refrigeration cycle system, and in this embodiment, it is set to fully closed as an example.

[0032] By completely closing the electronic expansion valve 24, a vacuum can be created from the electronic expansion valve 24 to the compressor, eliminating liquefied refrigerant and preventing it from accumulating in the piping. Therefore, liquid compression will not occur during the next startup, preventing damage to the compressor. The specified state does not have to be completely closed; it may also be fully open, or even slightly open with a small leak, as long as it can be maintained in a safe state. In other words, the specified state should be set appropriately according to the application and installation environment.

[0033] Furthermore, as a predetermined state, an initial value may be set as described above and applied at all times, or it may be possible to allow the user to change it as needed using, for example, a user PC 15. In other words, the user PC 15 functions as a setting unit for setting the predetermined state, and the predetermined state can be changed to the state set by the user PC (setting unit).

[0034] Returning to the explanation in Figure 3, if the result of the determination in step S107 is that an update is not in progress (step S107: No), the control microcontroller 6 stops the update (step S110) and starts overheat control (step S111). In other words, since writing to EEPROM 7 is complete and the update is finished, overheat control is started by the updated control program 71.

[0035] Next, the case where the operation instruction is referenced from the contact detection circuit 5 will be explained with reference to the flowchart in Figure 4. First, the control microcontroller 6 determines whether overheating control is in progress (step S201). In step S201, similar to step S101, the control microcontroller 6 determines whether the opening and closing control of the electronic expansion valve 24 is in progress.

[0036] If the result of the determination in step S201 indicates that overheat control is in progress (step S201: Yes), the control microcontroller 6 determines whether the start input is ON (step S202). In other words, it determines whether the operation instruction input from the contact detection circuit 5 is a start command. If the result of the determination in step S202 indicates that the start input is ON (step S202: Yes), the control microcontroller 6 continues overheat control (step S203) and controls the opening degree of the electronic expansion valve 24 (step S204). In other words, since there is no request for an update, normal operation continues.

[0037] On the other hand, if the result of the determination in step S202 is that the start input is not ON (step S202: No), the control microcontroller 6 stops the overheat control (step S205). In other words, since the operation instruction input from the contact detection circuit 5 is stopped (not ON), the overheat control is stopped.

[0038] On the other hand, if the result of the determination in step S201 is that overheat control is not in progress (step S201: No), the control microcontroller 6 determines whether the start input is ON (step S206). If the result of the determination in step S206 is that the start input is ON (step S206: Yes), the control microcontroller 6 determines whether the control program 71 is being updated (step S207). Step S206 is the same as step S202. Also, step S207 is the same as step S107 in Figure 3.

[0039] If the result of the determination in step S207 indicates that an update is in progress (step S207: Yes), the control microcontroller 6 continues the update (step S208). During this update, the opening of the electronic expansion valve 24 is set to fully closed (step S209). Steps S208 to S209 are the same as steps S108 to S109 in Figure 3.

[0040] If the result of the determination in step S207 is that an update is not in progress (step S207: No), the control microcontroller 6 starts overheat control (step S210). In the case of step S210, the start input is ON and an update is not in progress, so overheat control is started according to the instructions of the start input.

[0041] On the other hand, if the result of the determination in step S206 is that the start input is not ON (step S206: No), the control microcontroller 6 determines whether the control program 71 is being updated (step S211). If the result of the determination in step S211 is that the update is in progress (step S211: Yes), the control microcontroller 6 continues the update as is (step S212). Also, during this update, the opening of the electronic expansion valve 24 is set to fully closed (step S213). Steps S211 to S213 are the same as steps S207 to S209.

[0042] If the result of the determination in step S211 is that an update is not currently underway (step S211: No), the control microcontroller 6 determines whether there is a request to update the control program 71 (step S214). If the result of the determination in step S214 is that there is a request to update the control program (step S214: Yes), the control microcontroller 6 starts updating the control program 71 (step S215). In this case as well, the opening of the electronic expansion valve 24 is set to fully closed (step S216).

[0043] On the other hand, if the result of the determination in step S214 is that there is no request to update the control program 71 (step S214: No), the control microcontroller 6 stops updating the control program 71 (step S217). In other words, similar to step S110 in Figure 3, writing to the EEPROM 7 is completed and the update is finished. Note that in the case of step S217, the startup input is not ON (step S206: No), so the overheat control is not started.

[0044] In the flowchart of Figure 4, if step S206 is "No", an update is performed. In other words, the control microcontroller 6 determines whether it is possible to update the control program 71 based on the information regarding the operation instruction. Since an update is performed when step S206 branches to "No", the control microcontroller 6 determines that it is possible to update the control program 71 if the information regarding the operation instruction is an instruction indicating the cessation of normal operation.

[0045] Here, we will explain the state of steps S208 and S210. When starting an update, steps S201: No, S206: No, S211: No, and S214: Yes are executed. Therefore, the startup input is normally OFF during an update, but since the higher-level system 14 is not directly involved in the update operation, the startup input may be turned ON during the update. In that case, the update takes priority over the startup input, and the system proceeds to step S208 to continue the update. Once the update is complete, the system proceeds to step S210, and overheat control is started in response to the startup input being ON.

[0046] In other words, if the control microcontroller 6 switches from an OFF (indication indicating the cessation of normal operation) to an ON (indication indicating the start) during an update, it starts controlling the opening and closing of the electronic expansion valve 24 (electric valve) after the update is complete.

[0047] According to this embodiment, the controller 1 includes a control microcontroller 6 that controls the superheating degree of the refrigeration cycle system by controlling the opening and closing of the electronic expansion valve 24 using a control program 71 based on temperature data and pressure data, and a communication circuit 2 that receives an update program 151 from an external source. When the control microcontroller 6 is updating the control program 71 to the update program 151, it holds the electronic expansion valve 24 in a fully closed state.

[0048] By configuring the controller 1 as described above, the electronic expansion valve 24 can be kept in a fully closed state, allowing the control program 71 to be updated without affecting components such as the compressor that make up the refrigeration cycle system, when updating the program or when restarting after the update is complete.

[0049] Furthermore, the holding state of the electronic expansion valve 24 when the control program 71 is updated may be predetermined as an initial value. In this way, the control program can be updated while maintaining a safe state for most refrigeration cycle systems.

[0050] Furthermore, the user PC 15 may be able to set a predetermined state via the communication circuit 2, and change the state (fully closed, fully open, slight leakage, etc.) via the communication circuit 2. In this way, the setting can be changed to an appropriate state depending on the system.

[0051] Furthermore, the control microcontroller 6 is equipped with a contact detection circuit 5 to which operation instructions are input from a higher-level system 14, and the microcontroller 6 determines whether an update is possible based on the operation instructions. In this way, when updating the control program 71 based on operation instructions from the higher-level system 14, it is possible to update the program after confirming that there are no system malfunctions. For example, the control program 71 can be updated when the controller 1 is not expected to perform any control operations, such as when it is not in a startup state.

[0052] Furthermore, the control microcontroller 6 determines that it is possible to update the control program 71 if the operation instruction indicates the cessation of normal operation. Therefore, it recognizes that the overheat control, which is a normal operation, has stopped and that there are no system malfunctions, and proceeds with the update.

[0053] Furthermore, if the control microcontroller 6 switches from an instruction indicating the cessation of normal operation to an instruction indicating the start of operation while the control program 71 is being updated, it starts the opening and closing control of the electronic expansion valve 24 after the update of the control program 71 is complete. In this way, even if the controller 1 is in the process of updating the control program 71 and is unable to control the system, it can ignore the start instruction from the higher-level system 14 and complete the update until the update is finished, even if it is in the process of updating the control program 71.

[0054] In the embodiment described above, the update program 151 stored in the EEPROM 7 was simply updated. However, as shown in Figure 5, for example, two areas, area 7a and area 7b, may be provided in the storage area of ​​the EEPROM 7. If the control program 71 before the update is stored in area 7a, the update program 151 may be stored in area 7b, and then, when updating again, the update program 151 may be stored in area 7a. In other words, an area for storing the update program 151 and an area for storing the control program 71 before the update may be provided. Furthermore, these areas may be updated alternately.

[0055] The control microcontroller 6 then determines whether the update of the control program 71 was successful. If the update fails, it may switch back to the control program 71 before the update. In other words, it may read the control program 71 from the area where the control program 71 before the update is stored. The failure of the update can be determined using an error detection code, such as a checksum.

[0056] This approach allows the system to revert to the previous control program 71 even if the update fails. Therefore, at least the operation before the update can be guaranteed.

[0057] Furthermore, if the control microcontroller 6 receives an operation instruction from an instruction indicating the cessation of normal operation to an instruction indicating the start of operation while switching to the control program 71 before the update, it may start the opening and closing control of the electronic expansion valve 24 after the switchover is complete. In this way, similar to when updating the update program 151, even if the higher-level system 14 issues a start (operation) instruction while switching to the control program 71 before the update, the microcontroller 6 can ignore the start instruction and complete the switchover until the switchover is complete.

[0058] It should be noted that the present invention is not limited to the embodiments described above. That is, those skilled in the art can implement the invention in various ways without departing from the core principles, in accordance with prior art knowledge. As long as such modifications still incorporate the configuration of the electric valve control device of the present invention, they are of course included within the scope of the present invention. [Explanation of Symbols]

[0059] 1. Controller (Overheating Controller) 2. Communication circuit (receiving section) 5. Contact detection circuit (input section) 6. Control microcontroller (control unit, update unit) 7. EEPROM (Storage Unit) 15. User PC (Settings Section) 24. Electronic expansion valve (electric valve) 71 Control Program 151 Update (New Control Program)

Claims

1. A control unit that controls the degree of overheating of the refrigeration cycle system by controlling the opening and closing of an electric valve by a control program based on temperature information, A receiving unit that receives a new control program from an external source, An electric valve control device comprising an update unit for updating the control program to the new control program, The control unit holds the electric valve in a predetermined state while the update unit is performing the update. The electric valve control device further includes a setting unit for setting the predetermined state, The aforementioned predetermined state can be changed to the state set by the setting unit. An electric valve control device characterized by the following:

2. It further includes an input section that receives information regarding operation instructions from a higher-level device. The update unit determines whether the update is possible based on the information regarding the operation instruction. The electric valve control device according to claim 1.

3. The electric valve control device according to claim 2, characterized in that the update unit determines that the update is possible if the information regarding the operation instruction is an instruction indicating the cessation of normal operation.

4. The electric valve control device according to claim 3, characterized in that, if the information regarding the operation instruction changes from an instruction indicating the cessation of the normal operation to an instruction indicating the cessation of the normal operation during the update, the update unit causes the control unit to start opening and closing control of the electric valve after the update is completed.

5. The system further includes a storage unit for storing the control program, The electric valve control device according to claim 2, characterized in that the storage unit is provided with an area for storing the new control program and an area for storing the control program before the update.

6. The electric valve control device according to claim 5, wherein the update unit determines whether the update was successful, and if the update fails, switches back to the control program before the update.

7. The electric valve control device according to claim 6, characterized in that, if the information regarding the operation instruction changes from an instruction indicating the cessation of normal operation to an instruction indicating the start of operation while the update unit is switching to the control program prior to the update, the update unit causes the control unit to start the opening and closing control of the electric valve after the switchover is completed.

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