Dual system control method for a refrigerator

Abstract

The application provides a double-system control method of a refrigerator, which comprises the following steps: S1, obtaining a compressor starting signal and an open-stop ratio of a previous compressor working period; S2, if the open-stop ratio is less than 30%, a variable-frequency compressor is started first, and the fixed-frequency compressor is started or not started within a preset time after the variable-frequency compressor is started; if the open-stop ratio is greater than or equal to 30%, the fixed-frequency compressor is started first, and the variable-frequency compressor is started or not started within a preset time after the fixed-frequency compressor is started; and S3, obtaining a compressor stopping signal, and controlling the fixed-frequency compressor and / or the variable-frequency compressor to be turned off. According to the control method, the fixed-frequency compressor and the variable-frequency compressor are cooperated, different operations are performed on the start and stop of the fixed-frequency compressor and the variable-frequency compressor according to the open-stop ratio of the previous compressor start-stop period, the cooling speed is ensured, and the energy consumption is reduced after the temperature of the refrigeration chamber is stable.

Description

Technical Field

[0001] This invention relates to the field of refrigeration equipment technology, and in particular to a dual-system control method for a freezer. Background Technology

[0002] Large-capacity freezers have a large internal volume, and a single refrigeration system cannot meet the refrigeration requirements, so a dual refrigeration system is needed. However, currently, dual-system refrigeration uses dual fixed-frequency compressors, which have a slow refrigeration speed and consume a lot of energy once the temperature of the freezer compartment stabilizes. Summary of the Invention

[0003] The purpose of this invention is to provide a dual-system control method for a freezer, which uses a fixed-frequency compressor and a variable-frequency compressor. The start-up of the fixed-frequency compressor and the variable-frequency compressor is controlled according to the start-up / stop ratio of the compressors, which solves the problems of slow cooling and high energy consumption of dual fixed-frequency compressors in the prior art.

[0004] To achieve one of the aforementioned objectives, one embodiment of the present invention provides a dual-system control method for a freezer, the control method comprising:

[0005] S1. Obtain the compressor start signal and the start-stop ratio of the previous compressor working cycle;

[0006] S2. If the start-stop ratio is <30%, the variable frequency compressor will be started first. Within a preset time after the variable frequency compressor starts, the fixed frequency compressor will be started or not started. If the start-stop ratio is ≥30%, the fixed frequency compressor will be started first. Within a preset time after the fixed frequency compressor starts, the variable frequency compressor will be started or not started.

[0007] S3. Obtain the compressor stop signal and control the shutdown of the fixed-frequency compressor and / or variable-frequency compressor.

[0008] As a further improvement of one embodiment of the present invention, when the start-stop ratio is <30%, after controlling the start of the variable frequency compressor, it is determined whether a compressor stop signal is received within a preset time after the start of the variable frequency compressor. If so, the variable frequency compressor is controlled to be shut down; otherwise, the fixed frequency compressor is controlled to be started. After obtaining the compressor stop signal, both the fixed frequency compressor and the variable frequency compressor are controlled to be shut down.

[0009] As a further improvement of one embodiment of the present invention, when the start-stop ratio is <30%, the preset time after the variable frequency compressor starts is 60 minutes.

[0010] As a further improvement of one embodiment of the present invention, when the start-stop ratio is 30-50%, after the fixed-frequency compressor is started, it is determined whether a compressor stop signal is received within a preset time after the fixed-frequency compressor starts. If so, the fixed-frequency compressor is controlled to be shut down; otherwise, the variable-frequency compressor is controlled to be started. After obtaining the compressor stop signal, both the fixed-frequency compressor and the variable-frequency compressor are controlled to be shut down.

[0011] As a further improvement of one embodiment of the present invention, when the start-stop ratio is 30-50%, the preset time after the fixed-frequency compressor starts is 30 minutes.

[0012] As a further improvement of one embodiment of the present invention, when the start-stop ratio is >50%, after controlling the fixed-frequency compressor to start, it is determined whether a compressor stop signal is received within a preset time after the fixed-frequency compressor starts. If so, the fixed-frequency compressor is controlled to be shut down; otherwise, the variable-frequency compressor is controlled to start. After obtaining the compressor stop signal, both the fixed-frequency compressor and the variable-frequency compressor are controlled to be shut down.

[0013] As a further improvement of one embodiment of the present invention, when the start-stop ratio is 30-50%, the preset time after the fixed-frequency compressor starts is 1 minute.

[0014] As a further improvement to one embodiment of the present invention, after the freezer is initially powered on or the preset temperature T of the refrigeration compartment is adjusted, the dual-system control method of the freezer further includes:

[0015] S0, Obtain the room temperature T1;

[0016] If T1-T>8℃, the control will start the fixed-frequency compressor first, then start the variable-frequency compressor, with a 1-minute time interval between the start-up of the fixed-frequency compressor and the variable-frequency compressor. After obtaining the compressor shutdown signal, the control will shut down both the fixed-frequency compressor and the variable-frequency compressor.

[0017] If T1-T≤8℃, the variable frequency compressor will be started first. It will then be determined whether a compressor stop signal is received within a preset time after the variable frequency compressor starts. If so, the variable frequency compressor will be shut down. Otherwise, the fixed frequency compressor will be started. After receiving the compressor stop signal, both the fixed frequency compressor and the variable frequency compressor will be shut down.

[0018] As a further improvement of one embodiment of the present invention, when T1-T≤8℃, the preset time after the variable frequency compressor starts is 30 minutes.

[0019] As a further improvement to one embodiment of the present invention, when the freezer receives a quick-freeze command, the dual-system control method of the freezer further includes:

[0020] Upon receiving a quick-freeze command, the system controls the start of the fixed-frequency compressor first, followed by the start of the variable-frequency compressor. The start-up time interval between the fixed-frequency and variable-frequency compressors is 1 minute. After the preset time is reached, the system controls the shutdown of both the fixed-frequency and variable-frequency compressors.

[0021] As a further improvement of one embodiment of the present invention, the compressor start signal and compressor stop signal are specifically as follows: the preset temperature of the refrigeration room is T. When the temperature of the refrigeration room is T+1℃, it is a compressor start signal; when the temperature of the refrigeration room is T-1℃, it is a compressor stop signal.

[0022] One or more technical solutions provided by this invention have at least the following technical effects or advantages:

[0023] The dual-system control method provided by this invention employs a fixed-frequency compressor and a variable-frequency compressor. Depending on the different start-stop ratios within the previous compressor start-stop cycle, different operations are performed on the start-up and shutdown of the fixed-frequency compressor and the variable-frequency compressor. This allows the compressor to operate at a lower frequency when the required cooling capacity is small, reducing energy consumption; and to operate at a higher frequency when the required cooling capacity is large, reaching the preset temperature of the refrigerated room in a shorter time. Attached Figure Description

[0024] Figure 1 This is a flowchart of the initial power-on mode in an embodiment of the present invention.

[0025] Figure 2 This is a flowchart of the temperature control mode in an embodiment of the present invention.

[0026] Figure 3 This is a flowchart of the quick-freezing mode in an embodiment of the present invention. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] This invention provides a dual-system control method for a freezer, such as... Figure 2 As shown, the control methods include:

[0029] S1. Obtain the compressor start signal and the start-stop ratio of the previous compressor working cycle;

[0030] S2. If the start-stop ratio is <30%, the variable frequency compressor will be started first. Within a preset time after the variable frequency compressor starts, the fixed frequency compressor will be started or not started. If the start-stop ratio is ≥30%, the fixed frequency compressor will be started first. Within a preset time after the fixed frequency compressor starts, the variable frequency compressor will be started or not started.

[0031] S3. Obtain the compressor stop signal and control the shutdown of the fixed-frequency compressor and / or variable-frequency compressor.

[0032] This invention calculates the start-stop ratio of the compressor within one working cycle and controls the compressor in different ways for the next working cycle based on the different start-stop ratios within that working cycle.

[0033] When the start-stop ratio in the previous work cycle is less than 30%, that is, the start-up time in the previous work cycle is relatively short, starting the variable frequency compressor first can avoid unnecessary energy consumption caused by the high frequency of the fixed frequency compressor.

[0034] When the start-stop ratio in the previous work cycle is greater than or equal to 30%, that is, the start-up time of the previous work cycle is relatively long, the fixed-frequency compressor is started first, which can utilize the high frequency of the fixed-frequency compressor to provide sufficient cooling capacity to the refrigerated room in a short period of time.

[0035] The dual-system control method for freezers provided in this invention can solve the problems of slow cooling speed of large-capacity freezers by dual fixed-frequency compressors and high energy consumption caused by the invariable frequency of fixed-frequency compressors after the cooling compartment has basically stabilized, by controlling the start-up of fixed-frequency compressors and variable-frequency compressors according to the start-up ratio of compressors.

[0036] Specifically, in step S1, the start-stop ratio of the previous compressor working cycle is as follows: the start of the compressor starts and the next compressor start is a working cycle. Within this working cycle, the time when the fixed-frequency compressor and / or variable-frequency compressor is in the running state is recorded as t1, and the time when the fixed-frequency compressor and / or variable-frequency compressor is in the stopped state is recorded as t2. The start-stop ratio = t1 / t2.

[0037] The start-stop ratio within a work cycle can determine whether the compressor's operating time is too short or too long, thus indicating whether the compressor provides too little or too much cooling capacity to the refrigerated room during that work cycle. This helps in predicting the compressor's performance in the next work cycle.

[0038] The compressor start and stop signals are as follows: After the user selects a preset temperature T, the system sets a compressor start temperature T+1℃ and a compressor stop temperature T-1℃ based on the preset temperature T. Both the compressor start temperature T+1℃ and the compressor stop temperature T-1℃ are the temperatures inside the refrigeration room. That is, when the refrigeration room temperature reaches T+1℃, the compressor is controlled to start, which is the aforementioned compressor start signal; when the refrigeration room temperature reaches T-1℃, the compressor is controlled to stop, which is the aforementioned compressor stop signal.

[0039] Alternatively, after the user selects a preset temperature T, the system sets a compressor start temperature of T+3℃ and a compressor stop temperature of T-3℃ based on the preset temperature T. Both the compressor start temperature T+3℃ and the compressor stop temperature T-3℃ are temperatures at the evaporator. That is, when the evaporator temperature reaches T+3℃, the compressor is controlled to start, which is the aforementioned compressor start signal; when the evaporator temperature reaches T-3℃, the compressor is controlled to stop, which is the aforementioned compressor stop signal.

[0040] In step S2, when the start-stop ratio is less than 30%, a preset time of 60 minutes is set for the variable frequency compressor. After the variable frequency compressor starts, the timer starts and it is determined whether a compressor stop signal is received within the preset time of 60 minutes after the variable frequency compressor starts. If so, the variable frequency compressor is controlled to be shut down; otherwise, the fixed frequency compressor is controlled to be started. After obtaining the compressor stop signal, both the fixed frequency compressor and the variable frequency compressor are controlled to be shut down.

[0041] If the on / off ratio of the previous compressor working cycle is less than 30%, meaning the compressor working time is short and the cooling capacity produced after the compressor starts working is also small, it is predicted that the required cooling capacity in the next working cycle will also be small. In other words, the compressor frequency does not need to be too high. Since the frequency of the variable frequency compressor can be adjusted as needed, the variable frequency compressor is started first to allow it to work independently.

[0042] If the variable frequency compressor working alone can reach the aforementioned compressor stop temperature within the preset time of 60 minutes after the variable frequency compressor starts, the variable frequency compressor can be directly shut down without starting the fixed frequency compressor. However, if the variable frequency compressor working alone cannot reach the aforementioned compressor stop temperature for a long time, it will lead to low compressor efficiency. It is necessary to control the start of the fixed frequency compressor so that the fixed frequency compressor works together with the variable frequency compressor to improve the cooling speed and make the room quickly reach the compressor stop temperature.

[0043] In step S2, when the start-stop ratio is 30-50%, a preset time of 30 minutes is set for the fixed-frequency compressor. After the fixed-frequency compressor starts, the timer starts and it is determined whether a compressor stop signal is received within the preset time of 30 minutes after the fixed-frequency compressor starts. If so, the fixed-frequency compressor is controlled to be shut down; otherwise, the variable-frequency compressor is controlled to be started. After obtaining the compressor stop signal, both the fixed-frequency compressor and the variable-frequency compressor are controlled to be shut down.

[0044] The on-off ratio of the previous compressor cycle was 30-50%. Compared to the previous cycle with an on-off ratio of <30%, the compressor operated for a longer period and produced more cooling capacity. Therefore, it is predicted that the required cooling capacity for the next cycle will be greater than when the on-off ratio was <30%, meaning the compressor frequency will need to increase. Therefore, the higher-power fixed-frequency compressor will be started first and allowed to operate independently.

[0045] If a standalone fixed-frequency compressor can reach the aforementioned compressor stop temperature within a preset time of 30 minutes after the fixed-frequency compressor starts, the fixed-frequency compressor can be shut down directly without starting the variable-frequency compressor. However, if the fixed-frequency compressor fails to reach the aforementioned compressor stop temperature for an extended period of time when working alone, it will result in low compressor efficiency. In this case, it is necessary to control and start the variable-frequency compressor so that the fixed-frequency compressor and the variable-frequency compressor work together to increase the cooling speed and allow the cooling room to quickly reach the compressor stop temperature.

[0046] In step S2, when the start-stop ratio is greater than 50%, a preset time of 1 minute is set for the fixed-frequency compressor. After the fixed-frequency compressor starts, the timer starts and it is determined whether a compressor stop signal is received within the preset time of 1 minute after the fixed-frequency compressor starts. If so, the fixed-frequency compressor is controlled to be shut down; otherwise, the variable-frequency compressor is controlled to be started. After obtaining the compressor stop signal, both the fixed-frequency compressor and the variable-frequency compressor are controlled to be shut down.

[0047] The on-off ratio of the previous compressor cycle was >50%. Compared to the on-off ratio of 30-50% in the previous compressor cycle, the compressor's operating time was longer and the cooling capacity produced was greater. Therefore, it is predicted that the required cooling capacity in the next cycle will be greater than when the on-off ratio was 30-50%, meaning the compressor will need to operate more frequently. Therefore, the higher-power fixed-frequency compressor will be started first, allowing it to operate independently, further shortening the preset start-up time of the fixed-frequency compressor.

[0048] If a standalone fixed-frequency compressor can reach the aforementioned compressor stop temperature within a preset time of 1 minute after starting, the fixed-frequency compressor can be shut down directly without starting the variable-frequency compressor. However, since the preset time after starting the fixed-frequency compressor is shortened to 1 minute, if the aforementioned compressor stop temperature cannot be reached within 1 minute, the variable-frequency compressor is turned on, allowing the fixed-frequency compressor and the variable-frequency compressor to work together. Compared to an on / off ratio of 30-50%, this provides more cooling capacity in the same amount of time, thereby increasing the cooling speed and allowing the room to reach the compressor stop temperature more quickly.

[0049] The aforementioned steps S1-S3 are the control methods for the freezer under normal refrigeration conditions, referred to as temperature control mode. When the freezer is in temperature control mode, after the fixed-frequency compressor and / or variable-frequency compressor stop in step S3, it returns to step S1 for continuous cycling.

[0050] Furthermore, such as Figure 1 As shown, after the freezer is initially powered on or the preset temperature T of the refrigeration compartment is adjusted, the dual-system control method of the freezer further includes:

[0051] S0, Obtain the room temperature T1;

[0052] If T1-T>8℃, the control will start the fixed-frequency compressor first, followed by the variable-frequency compressor, with a 1-minute time interval between their start-up. Once the compressor shutdown signal is obtained, the control will shut down both the fixed-frequency and variable-frequency compressors. Here, T is the preset temperature of the refrigeration room.

[0053] If the temperature inside the refrigerated room is more than 8°C higher than the preset temperature, the large temperature difference requires a significant amount of cooling capacity. Therefore, the fixed-frequency compressor and the variable-frequency compressor are started sequentially, working together to rapidly generate a large amount of cooling capacity through the combined power of the two compressors, causing the temperature inside the refrigerated room to drop quickly. Starting the fixed-frequency and variable-frequency compressors 1 minute apart avoids the risk of excessive instantaneous current and potential damage to the electrical circuit caused by simultaneous startup.

[0054] If T1-T≤8℃, the variable frequency compressor is started first, and a preset time of 30 minutes is set for the variable frequency compressor. After the variable frequency compressor starts, the timer starts and it is determined whether a compressor stop signal is received within the preset time of 30 minutes after the variable frequency compressor starts. If so, the variable frequency compressor is shut down. Otherwise, the fixed frequency compressor is started, and after the compressor stop signal is obtained, both the fixed frequency compressor and the variable frequency compressor are shut down.

[0055] If the temperature difference between the room temperature and the preset temperature of the cooling room is within 8°C, the temperature difference is relatively small and the required cooling capacity is also small. Therefore, start the inverter compressor first and let it work alone.

[0056] If the variable frequency compressor working alone can reach the aforementioned compressor stop temperature within the preset time of 30 minutes after the variable frequency compressor starts, the variable frequency compressor can be directly shut down without starting the fixed frequency compressor. However, if the variable frequency compressor working alone cannot reach the aforementioned compressor stop temperature for a long time, it will lead to low compressor efficiency. It is necessary to control the start of the fixed frequency compressor so that the fixed frequency compressor works with the variable frequency compressor to improve the cooling speed and make the room quickly reach the compressor stop temperature.

[0057] Furthermore, such as Figure 3 As shown, when the freezer receives a quick-freeze command, the dual-system control method of the freezer also includes:

[0058] Upon receiving a quick-freeze command, the system controls the start of the fixed-frequency compressor first, followed by the start of the variable-frequency compressor. The start-up time interval between the fixed-frequency and variable-frequency compressors is 1 minute. After the preset time is reached, the system controls the shutdown of both the fixed-frequency and variable-frequency compressors.

[0059] The control method described above upon receiving a quick-freeze command is called quick-freeze mode. Because rapid freezing is required, necessitating a large amount of cooling capacity, the fixed-frequency compressor and variable-frequency compressor are started at 1-minute intervals, allowing them to operate continuously until a preset time is reached, at which point they are shut down. Quick-freeze mode can be set after the initial power-on mode or after the temperature control mode; that is, after the fixed-frequency compressor and / or variable-frequency compressor stops in step S0 or step S3, quick-freeze mode can be entered.

[0060] It should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This way of describing the specification is only for clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

[0061] The detailed descriptions listed above are merely specific descriptions of feasible embodiments of the present invention, and are not intended to limit the scope of protection of the present invention. All equivalent embodiments or modifications made without departing from the spirit of the present invention should be included within the scope of protection of the present invention.

Claims

1. A dual-system control method for a freezer, characterized in that, The control method includes: S1. Obtain the compressor start signal and the start-stop ratio of the previous compressor working cycle; S2. If the start-stop ratio is <30%, the variable frequency compressor is started first. Within a preset time after the variable frequency compressor starts, it is determined whether a compressor stop signal is received. If yes, the variable frequency compressor is shut down; otherwise, the fixed frequency compressor is started. If the start-stop ratio is ≥30%, the fixed frequency compressor is started first. Within a preset time after the fixed frequency compressor starts, it is determined whether a compressor stop signal is received. If yes, the fixed frequency compressor is shut down; otherwise, the variable frequency compressor is started. S3. Obtain the compressor stop signal and control the shutdown of the fixed-frequency compressor and / or variable-frequency compressor.

2. The dual-system control method for a freezer according to claim 1, characterized in that, When the start-stop ratio is less than 30%, the preset time after the variable frequency compressor starts is 60 minutes.

3. The dual-system control method for a freezer according to claim 1, characterized in that, When the start-stop ratio is 30-50%, the preset time after the fixed-frequency compressor starts is 30 minutes.

4. The dual-system control method for a freezer according to claim 1, characterized in that, When the start-stop ratio is 30-50%, the preset time after the fixed-frequency compressor starts is 1 minute.

5. The dual-system control method for a freezer according to claim 1, characterized in that, After the freezer is initially powered on or the preset temperature T of the refrigeration compartment is adjusted, the dual-system control method of the freezer further includes: S0, Obtain the room temperature T1; If T1-T>8℃, the control will start the fixed-frequency compressor first, then start the variable-frequency compressor, with a 1-minute time interval between the start-up of the fixed-frequency compressor and the variable-frequency compressor. After obtaining the compressor shutdown signal, the control will shut down both the fixed-frequency compressor and the variable-frequency compressor. If T1-T≤8℃, the variable frequency compressor will be started first. It will then be determined whether a compressor stop signal is received within a preset time after the variable frequency compressor starts. If so, the variable frequency compressor will be shut down. Otherwise, the fixed frequency compressor will be started. After receiving the compressor stop signal, both the fixed frequency compressor and the variable frequency compressor will be shut down.

6. The dual-system control method for a freezer according to claim 5, characterized in that, When T1-T≤8℃, the preset time after the variable frequency compressor starts is 30 minutes.

7. The dual-system control method for a freezer according to claim 1, characterized in that, When the freezer receives a quick-freeze command, the dual-system control method for the freezer further includes: Upon receiving a quick-freeze command, the system controls the start of the fixed-frequency compressor first, followed by the start of the variable-frequency compressor. The start-up time interval between the fixed-frequency and variable-frequency compressors is 1 minute. After the preset time is reached, the system controls the shutdown of both the fixed-frequency and variable-frequency compressors.

8. The dual-system control method for a freezer according to any one of claims 1-7, characterized in that, The compressor start signal and compressor stop signal are as follows: the preset temperature of the refrigeration room is T. When the temperature of the refrigeration room is T+1℃, it is a compressor start signal; when the temperature of the refrigeration room is T-1℃, it is a compressor stop signal.

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