阅读说明：本技术 一种冷藏冷冻机组的控制方法及冷藏冷冻机组 (Control method of refrigeration and freezing unit and refrigeration and freezing unit ) 是由 孟庆良 赵俊东 宋强 于 2021-05-28 设计创作，主要内容包括：本发明涉及一种冷藏冷冻机组的控制方法及使用该控制方法的冷藏冷冻机组。该控制方法包括：检测所述冷藏冷冻机组的室内温度；将所述室内温度与设定停机温度进行比较；当所述室内温度小于所述设定停机温度时,控制所述冷藏冷冻机组的室内电磁阀断开；获取所述冷藏冷冻机组的压缩机的开机运行时长；将所述开机运行时长与设定最小运行时长进行比较；并且基于所述开机运行时长与所述设定最小运行时长的比较结果,控制所述压缩机进入延时停机模式或者正常停机模式。该控制方法能够确保压缩机满足设定最小运行时长的要求,以延长压缩机的使用寿命。(The invention relates to a control method of a refrigeration and freezing unit and the refrigeration and freezing unit using the control method. The control method comprises the following steps: detecting the indoor temperature of the refrigerating and freezing unit; comparing the indoor temperature with a set shutdown temperature; when the indoor temperature is lower than the set shutdown temperature, controlling an indoor electromagnetic valve of the refrigerating and freezing unit to be disconnected; acquiring the starting operation time of a compressor of the refrigerating and freezing unit; comparing the starting-up operation time length with a set minimum operation time length; and controlling the compressor to enter a delayed shutdown mode or a normal shutdown mode based on a comparison result of the starting-up operation time length and the set minimum operation time length. The control method can ensure that the compressor meets the requirement of setting the minimum running time so as to prolong the service life of the compressor.)

1. A method of controlling a refrigeration and freezing assembly, the method comprising:

detecting the indoor temperature of the refrigerating and freezing unit;

comparing the indoor temperature with a set shutdown temperature;

when the indoor temperature is lower than the set shutdown temperature, controlling an indoor electromagnetic valve of the refrigerating and freezing unit to be disconnected;

acquiring the starting operation time of a compressor of the refrigerating and freezing unit;

comparing the starting-up operation time length with a set minimum operation time length; and is

And controlling the compressor to enter a delayed shutdown mode or a normal shutdown mode based on the comparison result of the starting-up operation time length and the set minimum operation time length.

2. A control method for a refrigeration and freezing unit as claimed in claim 1, wherein the compressor enters the delayed shutdown mode when the on-time operation duration is less than the set minimum operation duration.

3. A method of controlling a refrigeration and freezing assembly as claimed in claim 2, wherein the delayed shutdown mode comprises:

detecting a suction pressure of the compressor;

when the suction pressure is smaller than a preset pressure threshold, acquiring the current starting operation time;

when the current starting operation time length is less than the set minimum operation time length, controlling an outdoor bypass electromagnetic valve connected with the compressor in parallel to be closed and keeping the outdoor bypass electromagnetic valve for a first preset time period;

after the first preset time period, controlling the outdoor bypass electromagnetic valve to be disconnected,

and the first preset time period is equal to the difference value between the set minimum running time length and the current starting running time length.

4. A control method for a refrigeration and freezing unit as set forth in claim 3, wherein when the current on-time operating duration is equal to or greater than the set minimum operating duration,

detecting the current suction pressure;

comparing the current suction pressure with a set shutdown pressure;

controlling the compressor to stop when the suction pressure is less than the set stop pressure and keeps for a second preset time period,

wherein the set shutdown pressure is less than the preset pressure threshold.

5. A method of controlling a refrigeration and freezing assembly as recited in claim 3 wherein the delayed shutdown mode further comprises:

after the outdoor bypass electromagnetic valve is controlled to be switched off, the current suction pressure is detected again;

comparing the current suction pressure with a set shutdown pressure;

controlling the compressor to stop when the suction pressure is less than the set stop pressure and keeps for a second preset time period,

wherein the set shutdown pressure is less than the preset pressure threshold.

6. A control method for a refrigeration and freezing unit as claimed in claim 1, wherein the compressor enters the normal shutdown mode when the startup operation duration is greater than or equal to the set minimum operation duration.

7. A control method for a refrigeration and freezing unit as claimed in claim 6, wherein the normal shutdown mode comprises:

detecting a suction pressure of the compressor;

comparing the suction pressure to a set shutdown pressure;

and when the suction pressure is smaller than the set shutdown pressure and is kept for a second preset time period, controlling the compressor to be shut down.

8. A method of controlling a refrigeration and freezing assembly as recited in claim 1 further comprising:

detecting the temperature of a coil of the refrigerating and freezing unit;

comparing the coil temperature to a set frosting temperature;

and when the temperature of the coil is less than the set frosting temperature, controlling a defrosting component of the refrigerating and freezing unit to be started and kept for a third preset time period.

9. A method of controlling a refrigeration and freezing assembly as recited in claim 1 further comprising:

detecting the indoor temperature;

comparing the indoor temperature with a set starting temperature;

when the indoor temperature is greater than or equal to the set starting temperature, controlling the indoor electromagnetic valve to be closed, and controlling an outdoor bypass electromagnetic valve connected with the compressor in parallel to be closed;

detecting a suction pressure of the compressor;

comparing the suction pressure with a set starting pressure; and

and when the suction pressure is greater than or equal to the set starting pressure, the outdoor bypass electromagnetic valve is controlled to be switched off, and the compressor is controlled to start.

10. A refrigerator-freezer unit, characterized in that the refrigerator-freezer unit comprises a compressor and that the refrigerator-freezer unit controls the starting or stopping of the compressor using a control method according to any one of claims 1-9.

Technical Field

The invention relates to the technical field of refrigeration, in particular to a control method of a refrigerating and freezing unit and the refrigerating and freezing unit.

Background

In the modern industrial and agricultural production process, the refrigerating and freezing unit can provide effective temperature control, so that the production efficiency and the product quality are continuously improved, and therefore, the refrigerating and freezing unit is widely applied to the fields of food processing, mechanical manufacturing, medicine production, grain storage and the like. Refrigeration and freezing units, including but not limited to water-cooled units and air-cooled units, may be used to cool refrigerators directly with a refrigerant (also referred to as "refrigerant") to provide suitable refrigeration and/or freezing temperatures. Some refrigeration and freezing units employ a vapor compression refrigeration cycle, such as using a screw compressor or scroll compressor. The refrigeration and freezing unit further includes at least a condenser, an evaporator, and an expansion device. The refrigerating-freezing unit can be divided into two parts, an outdoor unit (which is usually placed in an outdoor environment) and an indoor unit (which is usually placed in an indoor environment to be temperature-regulated, for example a cold storage) which are interconnected with each other. The compressor and the condenser are disposed in the outdoor unit, and the evaporator and the expansion device are disposed in the indoor unit. In the refrigeration cycle, the compressor sucks a low-temperature and low-pressure gaseous refrigerant through the suction port and compresses the refrigerant into a high-temperature and high-pressure gaseous refrigerant. The high-temperature and high-pressure gaseous refrigerant is discharged from a discharge port of the compressor and flows into the condenser along a pipe. In the condenser, a high-temperature and high-pressure gaseous refrigerant is condensed into a medium-temperature and high-pressure liquid refrigerant by means of an air cooling or water cooling method. The medium-temperature high-pressure liquid refrigerant flows from the condenser to the expansion device along the pipeline, and is throttled in the expansion device into low-temperature low-pressure liquid refrigerant. Then, the low-temperature low-pressure liquid refrigerant flows along the pipeline to the evaporator. In the evaporator, the liquid refrigerant is evaporated into a low-temperature and low-pressure gaseous refrigerant by absorbing heat of the indoor air, and the indoor air is cooled to a predetermined target refrigerating temperature or a target freezing temperature. The low-temperature and low-pressure gaseous refrigerant is then sucked and compressed again by the compressor, thereby starting a new refrigeration cycle.

In order to improve the quality of the refrigerating and freezing unit, it is a focus of attention to extend the service life of the compressor. The main factors affecting the service life of the compressor include: the running time, the environmental temperature, the manual operation, the starting and stopping times and the like of the unit. Frequent starting and stopping can increase energy consumption, and can generate large impact on parts of the compressor, so that the compressor is easily damaged. The frequent start-stop comprises frequent start-stop under abnormal conditions and frequent start-stop under normal conditions. Under abnormal conditions, such as excessive high pressure or excessive current, the compressor may trigger overload protection and cause a protective shutdown. The prior art has made a great deal of research, focusing on compressor protection under abnormal conditions. However, the compressor may be frequently started and stopped under normal conditions (for example, when the design accuracy of the indoor target temperature is too low or a user erroneously operates the compressor). Generally, the maximum number of times (for example, 20 ten thousand times) of starting and stopping the compressor is present, and if the compressor is frequently started and stopped in a short time and lacks corresponding protection, the service life of the compressor is inevitably influenced.

Accordingly, there is a need in the art for a new solution to the above problems.

Disclosure of Invention

In order to solve the above problems in the prior art, that is, to solve the technical problem of frequent start and stop of the existing compressor under normal conditions, the present invention provides a control method for a refrigeration and freezing unit, wherein the control method comprises:

detecting the indoor temperature of the refrigerating and freezing unit;

comparing the indoor temperature with a set shutdown temperature;

when the indoor temperature is lower than the set shutdown temperature, controlling an indoor electromagnetic valve of the refrigerating and freezing unit to be disconnected;

acquiring the starting operation time of a compressor of the refrigerating and freezing unit;

comparing the starting-up operation time length with a set minimum operation time length; and is

And controlling the compressor to enter a delayed shutdown mode or a normal shutdown mode based on the comparison result of the starting-up operation time length and the set minimum operation time length.

It will be appreciated by those skilled in the art that in the control method of the refrigeration and freezing unit of the present invention, the indoor temperature of the refrigeration and freezing unit is detected and compared with the set shutdown temperature. When the indoor temperature is lower than the set shutdown temperature, it is indicated that the indoor side temperature has reached the set target temperature. In this case, the indoor solenoid valve is controlled to be turned off so that the refrigerant is not delivered to the indoor unit any more, so that the indoor temperature is prevented from continuously decreasing and deviating from the set target temperature. Further, the starting operation time length of a compressor of the refrigerating and freezing unit is obtained, then the starting operation time length is compared with the set minimum operation time length, whether the starting operation time length reaches the set minimum operation time length or not is judged, and therefore the compressor is controlled to enter a delayed shutdown mode or a normal shutdown mode. Therefore, when the outdoor unit is in a stoppable state, the control method can ensure that the compressor operates for at least the minimum running time, thereby effectively avoiding the technical problem that the compressor is frequently started and stopped in a short time under normal conditions.

In a preferred technical solution of the control method for the refrigerating and freezing unit, when the starting-up operation duration is shorter than the set minimum operation duration, the compressor enters the delayed shutdown mode.

In a preferred embodiment of the above method for controlling a refrigeration and freezing unit, the delayed stop mode includes:

detecting a suction pressure of the compressor;

when the suction pressure is smaller than a preset pressure threshold, acquiring the current starting operation time;

when the current starting operation time length is less than the set minimum operation time length, controlling an outdoor bypass electromagnetic valve connected with the compressor in parallel to be closed and keeping the outdoor bypass electromagnetic valve for a first preset time period;

after the first preset time period, controlling the outdoor bypass electromagnetic valve to be disconnected,

and the first preset time period is equal to the difference value between the set minimum running time length and the current starting running time length. Because the indoor electromagnetic valve is disconnected, the load of the compressor is reduced, and the suction pressure is gradually reduced. And when the suction pressure is reduced to a preset pressure threshold value, acquiring the current starting operation time of the compressor. If the current starting operation time length is still less than the set minimum operation time length, the compressor needs to be stopped in a delayed mode on one hand, and on the other hand, the risk of stopping exists when the suction pressure is too small. Therefore, the outdoor bypass electromagnetic valve connected with the compressor in parallel is controlled to be closed, so that the compressor can keep a certain suction pressure to normally operate. In addition, the outdoor bypass electromagnetic valve is kept closed in a first preset time period, and the first preset time period is equal to the difference value between the set minimum operation time length and the current starting operation time length, so that the starting operation time length of the compressor can meet the requirement of the set minimum operation time length.

In a preferred embodiment of the above-mentioned control method for a refrigerating and freezing unit, when the current startup operation duration is longer than or equal to the set minimum operation duration,

detecting the current suction pressure;

comparing the current suction pressure with a set shutdown pressure;

controlling the compressor to stop when the suction pressure is less than the set stop pressure and keeps for a second preset time period,

wherein the set shutdown pressure is less than the preset pressure threshold. When the current starting operation time length is more than or equal to the set minimum operation time length, the starting operation time length of the compressor meets the requirement of the set minimum operation time length, and therefore the compressor is controlled to normally stop only on the basis of comparison between the suction pressure and the set stop pressure. The reason that the suction pressure is smaller than the set stop pressure and is kept for the second preset time period is to determine that the condition that the suction pressure is smaller than the set stop pressure is stable, namely, the condition that the suction pressure is lower than the set stop pressure and then suddenly rises to exceed the set stop pressure is avoided, and therefore the frequent start-stop frequency of the compressor is reduced.

In a preferred embodiment of the above method for controlling a refrigeration and freezing unit, the delayed shutdown mode further includes:

after the outdoor bypass electromagnetic valve is controlled to be switched off, the current suction pressure is detected again;

comparing the current suction pressure with a set shutdown pressure;

controlling the compressor to stop when the suction pressure is less than the set stop pressure and keeps for a second preset time period,

wherein the set shutdown pressure is less than the preset pressure threshold. After the outdoor bypass electromagnetic valve is closed and kept for a first preset time period, the compressor continues to operate, the starting operation time of the compressor meets the requirement of the set minimum operation time, and the compressor is controlled to normally stop only based on the comparison between the suction pressure and the set stop pressure.

In a preferred technical solution of the control method for the refrigerating and freezing unit, when the starting-up operation time period is longer than or equal to the set minimum operation time period, the compressor enters the normal shutdown mode.

In a preferred embodiment of the above method for controlling a refrigerator/freezer unit, the normal stop mode includes:

detecting a suction pressure of the compressor;

comparing the suction pressure to a set shutdown pressure;

and when the suction pressure is smaller than the set shutdown pressure and is kept for a second preset time period, controlling the compressor to be shut down. When the indoor temperature is lower than the set stop temperature and the starting operation time of the compressor is longer than or equal to the set minimum operation time, the compressor is controlled to normally stop based on the comparison between the suction pressure and the set stop pressure. The reason that the suction pressure is smaller than the set stop pressure and is kept for the second preset time period is to determine that the condition that the suction pressure is smaller than the set stop pressure is stable, namely, the condition that the suction pressure is lower than the set stop pressure and then suddenly rises to exceed the set stop pressure is avoided, and therefore the frequent start-stop frequency of the compressor is reduced.

In a preferred embodiment of the above method for controlling a refrigerator-freezer unit, the method further includes:

detecting the temperature of a coil pipe of an indoor unit of the refrigerating and freezing unit;

comparing the coil temperature to a set frosting temperature;

and when the temperature of the coil is less than the set frosting temperature, controlling a defrosting component of the refrigerating and freezing unit to be started and kept for a third preset time period. When the temperature of the coil pipe is lower than the set frosting temperature, the phenomenon that the heat exchanger of the indoor unit frosts is explained, so that the defrosting component is controlled to be started and kept for a third preset time period, the frosting of the heat exchanger of the indoor unit can be effectively avoided, and the refrigerating efficiency is improved.

In order to solve the above problems in the prior art, that is, to solve the technical problem of frequent start and stop of the existing compressor during normal operation, the present invention further provides a refrigeration and freezing unit, wherein the refrigeration and freezing unit comprises a compressor, and the refrigeration and freezing unit controls the start or stop of the compressor by using the control method according to any one of the above. By using the control method, the refrigeration and freezing unit can ensure that the compressor is operated at least for the set minimum operation time, and the compressor is not frequently started and stopped in a short time, so that the service life of the compression is effectively prolonged.

Drawings

Preferred embodiments of the present invention are described below with reference to the accompanying drawings, in which:

FIG. 1 is a system schematic of an embodiment of a refrigeration and freezing assembly of the present invention;

fig. 2 is a flow chart of a method of controlling a refrigeration and freezing unit according to the present invention;

fig. 3 is a flow chart of a first embodiment of a method of controlling a refrigeration and freezing assembly in accordance with the present invention;

fig. 4 is a flow chart of a second embodiment of a method of controlling a refrigeration and freezing assembly in accordance with the present invention;

fig. 5 is a flowchart of a method of controlling a refrigeration-freezing unit according to a third embodiment of the present invention.

List of reference numerals:

1. a refrigeration and freezing unit; 11. an outdoor unit; 111. a compressor; 111a, compressor heating belt; 112a, an exhaust pipe; 112b, liquid pipe; 112c, a gas pipe; 112d, an air suction pipe; 113. a high voltage protection switch; 114. an oil separator; 115. an oil return capillary tube; 116. a one-way valve; 117. a high pressure sensor; 118. an outdoor heat exchanger; 119. a high pressure reservoir; 119a, a high-pressure reservoir heating belt; 120. drying the filter; 121. a liquid viewing mirror; 122. a liquid pipe stop valve; 123. an air pipe stop valve; 124. a gas-liquid separator; 125. a low pressure sensor; 126. a hot defrosting bypass pipeline; 127. a hot defrosting stop valve; 128. an outdoor balanced bypass line; 129. an outdoor bypass electromagnetic valve; 21. an indoor unit; 211. an indoor heat exchanger; 212. an expansion valve; 213. an indoor solenoid valve.

Detailed Description

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention, and are not intended to limit the scope of the present invention.

The invention provides a control method of a refrigeration and freezing unit, aiming at solving the technical problem of frequent start and stop of a compressor during normal operation in the prior art. A refrigerator-freezer unit 1 includes a compressor 111, and the control method includes:

detecting the indoor temperature of the refrigerating and freezing unit (step S1);

comparing the indoor temperature with a set shutdown temperature (step S2);

when the indoor temperature is lower than the set shutdown temperature, controlling an indoor electromagnetic valve of the refrigeration and freezing unit to be switched off (step S3);

acquiring the starting operation time of a compressor of the refrigerating and freezing unit (step S4);

comparing the power-on operation time length with a set minimum operation time length (step S5); and is

And controlling the compressor to enter a delayed shutdown mode or a normal shutdown mode based on the comparison result of the startup operation time length and the set minimum operation time length (step S6).

Figure 1 is a system schematic of an embodiment of a refrigeration and freezing assembly of the present invention. As shown in fig. 1, in one or more embodiments, the refrigeration-freezer unit 1 includes an outdoor unit 11 (which is typically disposed in an outdoor environment) and one indoor unit 21 (which is typically disposed indoors or in a room). Alternatively, the refrigerating-freezing unit 1 may be provided with a plurality of parallel-connected indoor units, for example two, three, four or another suitable number of indoor units. Fig. 1 shows only one indoor unit 21. In the case where a plurality of indoor units are arranged, the arrangement of the plurality of indoor units may be the same or different depending on actual needs.

As shown in fig. 1, in one or more embodiments, the outdoor unit 11 mainly includes a compressor 111, an outdoor heat exchanger 118, a high-pressure accumulator 119, and a gas-liquid separator 124; the indoor unit 21 mainly includes an indoor heat exchanger 211, an expansion valve 212, and an indoor solenoid valve 213. The compressor 111 has a discharge port and a suction port (not shown). The discharge port of the compressor 111 is connected to the input end of the outdoor heat exchanger 118 through a discharge pipe 112 a; the output end of the outdoor heat exchanger 118 is connected to the high-pressure reservoir 119, the expansion valve 212 of the indoor unit 21, and the indoor heat exchanger 211 in this order through the liquid pipe 112 b; the indoor heat exchanger 211 is connected to an inlet of the gas-liquid separator 124 through a gas pipe 112c, and an outlet of the gas-liquid separator 124 is connected to an inlet of the compressor 111 through a suction pipe 112d, thereby being interconnected to form a refrigeration cycle allowing a refrigerant to flow therein.

As shown in FIG. 1, in one or more embodiments, the compressor 111 is an inverter compressor. Alternatively, the compressor 111 may include two or more compressors in parallel. These compressors may be all inverter compressors or may include some inverter compressors. In one or more embodiments, a high pressure protection switch 113 is disposed on the discharge line 112a near the discharge of the compressor 111 to provide shutdown protection when the discharge pressure of the compressor 111 is too high. In one or more embodiments, an oil separator 114 is disposed on the gas discharge pipe 112a, wherein a gas input end of the oil separator 114 is connected to a gas discharge port of the compressor 111; the gas output of the oil separator 114 is connected to the input of the outdoor heat exchanger 118 through the gas discharge pipe 112 a; the oil return discharge end of the oil separator 114 is connected to an oil return capillary tube 115 and is connected to the suction port of the compressor 111 through a pipe so as to return the lubricating oil to the compressor 111 in time. In one or more embodiments, a compressor heating belt 111a is provided at the bottom of the compressor 111 to preheat the compressor 111 when needed. In one or more embodiments, a check valve 116 for preventing the refrigerant from flowing backwards and a high pressure sensor 117 for detecting the discharge pressure of the compressor 111 are further disposed on the discharge pipe 112a, and both the check valve 116 and the pressure sensor 117 are located downstream of the gas output end of the oil separator 114.

As shown in fig. 1, in one or more embodiments, the outdoor heat exchanger 118 may be, but is not limited to, a finned coil heat exchanger or a plate heat exchanger, and is equipped with an outdoor heat exchanger fan (not shown). The high pressure accumulator 119 may receive the liquid refrigerant condensed by the outdoor heat exchanger 118 to adjust and ensure a refrigerant circulation amount in the refrigeration system. In one or more embodiments, a high pressure accumulator heating belt 119a is provided on the high pressure accumulator 119 to preheat the liquid refrigerant, ensuring accurate supply of the refrigerant. A dry filter 120, a sight glass 121, and a liquid pipe shutoff valve 122 are also connected in series in this order to the liquid pipe 112b downstream of the high-pressure accumulator 119. The desiccant filter 120 may dry moisture in the liquid refrigerant, the liquid viewing mirror 121 may be used to observe a flow condition of the liquid refrigerant and detect a water content in the refrigerant, and the liquid tube stop valve 122 may help to temporarily store the refrigerant in the refrigeration cycle loop outside the room, so as to facilitate assembly, disassembly, maintenance and repair of the refrigeration and freezing unit 1. In one or more embodiments, an indoor solenoid valve 213 is further disposed at a position of the liquid pipe 112b upstream of the expansion valve 212 to control the liquid refrigerant to flow into the indoor unit 21.

As shown in fig. 1, in one or more embodiments, the expansion valve 212 is a thermal expansion valve. Alternatively, the expansion valve 212 may be an electronic expansion valve, or other suitable expansion valve. The indoor heat exchanger 211 includes, but is not limited to, a fin-and-coil heat exchanger or a plate heat exchanger, and is provided with an indoor heat exchanger fan (not shown in the drawings). The gas pipe 112c is further provided with a gas pipe shutoff valve 123 to assist the refrigerant in the refrigeration cycle circuit to be temporarily stored outside the room in cooperation with the liquid pipe shutoff valve 122.

As shown in FIG. 1, in one or more embodiments, a low pressure sensor 125 is further disposed on the suction pipe 112d for detecting a suction pressure P of the compressor 111_s. In one or more embodiments, a hot defrosting bypass line 126 is connected in parallel between the gas output end close to the oil-gas separator 114 and the output end of the indoor heat exchanger 211, and a hot defrosting stop valve 127 is arranged on the hot defrosting bypass line 126, so that when the indoor heat exchanger 211 needs defrosting, the hot defrosting stop valve 127 is opened, and the high-temperature and high-pressure gaseous refrigerant output from the exhaust port of the compressor 111 is allowed to be directly delivered to the indoor heat exchanger 211 through the hot defrosting bypass line 126 for defrosting treatment. In one or more embodiments, an outdoor balance bypass line 128 is connected in parallel between the exhaust pipe 112a and the suction pipe 112d, and an outdoor bypass solenoid valve 129 is disposed on the outdoor balance bypass line 128.

When the refrigerating and freezing unit 1 receives a cooling instruction, the compressor 111 starts to operate, and the refrigerant (for example, R410a) is compressed by the compressor 111 and then enters the outdoor heat exchanger 118 (which serves as a condenser) through the discharge pipe 112a in the form of a high-temperature and high-pressure gas. In the outdoor heat exchanger 118, the high-temperature and high-pressure gas refrigerant is condensed into a high-temperature and high-pressure liquid refrigerant by transferring heat to an air flow caused by the outdoor heat exchanger fan. The high-temperature and high-pressure liquid refrigerant flows through the high-pressure accumulator 119, the dry filter 120, the liquid scope 121, and the liquid tube shutoff valve 122 in this order, and flows to the expansion valve 212 of the indoor unit 21. The expansion valve 212 throttles the high-temperature and high-pressure liquid refrigerant to a low-temperature and low-pressure liquid refrigerant, and distributes the refrigerant to the indoor heat exchanger 211. The low-temperature and low-pressure liquid refrigerant is evaporated into a low-temperature and low-pressure gas refrigerant by absorbing heat of the indoor air, and the indoor air is cooled. The low-temperature and low-pressure gaseous refrigerant exits the indoor heat exchanger 211, passes through the corresponding gas pipe 112c and the gas pipe shutoff valve 123, and then enters the gas-liquid separator 124. The gas-liquid separated refrigerant gas is sucked into the compressor 111 through the suction port. A complete refrigeration cycle is completed and such refrigeration cycle can be performed without interruption in order to achieve the target refrigeration temperature.

The method for controlling the refrigeration and freezing unit according to the present invention will be described in detail based on the refrigeration and freezing unit 1. It should be noted that the control method of the present invention can also be used for other suitable refrigeration equipment.

Fig. 2 is a flowchart of a method of controlling a refrigeration-freezing unit according to the present invention. As shown in fig. 2, the method for controlling the refrigerating and freezing unit first detects the indoor temperature T of the refrigerating and freezing unit 1 after the start of the control_n(step S1), the detected indoor temperature T is measured again_nAnd setting the shutdown temperature T_tComparison is performed (step S2). Indoor temperature T_nIs the indoor ambient temperature, such as the temperature in the warehouse. Indoor temperature T_nMay be a temperature measured from the inlet of the indoor unit 21 or other suitable location in the room. When indoor temperature T_nLess than a set shutdown temperature T_tIn this case, the indoor solenoid valve 213 of the indoor unit 21 is controlled to be off (step S3). For example, the shutdown temperature T is set_tAt-15 deg.C, the actually detected indoor temperature T_nAt-17 deg.C, at which the room temperature T is_nLess than a set shutdown temperature T_tWhen the indoor temperature has reached the temperature request set by the user, the indoor solenoid valve 213 is controlled to be turned off. Further, the startup operation time t of the compressor 111 of the refrigeration and freezing unit 1 is obtained_y(step S4), the starting up operation time length t is set again_yAnd setting a minimum operation time t_minComparing (step S5), and according to the starting operation time length t_yAnd setting a minimum operation time t_minAs a result of the comparison, the compressor 111 is controlled to enter the delayed stop mode or the normal stop mode (step S6).

Fig. 3 is a flowchart of a control method of a refrigerating and freezing unit according to a first embodiment of the present invention. As shown in fig. 3, after the start of the control method, the control method executes step S1 to detect the indoor temperature T of the refrigerating and freezing unit 1_n. Will detect the indoor temperature T_nAnd setting the shutdown temperature T_tComparison is performed (step S2). When indoor temperature T_nLess than a set shutdown temperature T_tIn this case, the indoor solenoid valve 213 of the indoor unit 21 is controlled to be off (step S3). Obtaining the starting operation time t of the compressor 111 of the refrigerating and freezing unit 1_y(step S4), the starting up operation time length t_yAnd setting a minimum operation time t_minComparison is performed (step S5).

As shown in FIG. 3, the time duration t is when the computer is turned on_yLess than a set minimum operating time t_minThe compressor 111 is controlled to enter the delayed shutdown mode. In one or more embodiments, a minimum operating time period t is set_minIs 4min (minutes), and the starting operation time period of the compressor 111 is 1min (minutes), which indicates the starting operation time period t of the compressor 111_yDoes not reach the set minimum operation time t_minAnd thus controls the compressor 111 to enter the delayed shutdown mode. It will be appreciated that a minimum operating time period t is set_minCan be determined according to the design service life of the compressor 111, and can be set by the user according to the actual requirement. When the compressor 111 enters the delayed stop mode, step S61 is executed to detect the suction pressure P of the compressor 111_sThen the detected suction pressure P is measured_sWith a predetermined pressure threshold value P_fComparison is performed (step S62). When suction pressure P_sLess than a predetermined pressure threshold P_fNow, the suction pressure P of the compressor 111 will be described_sToo low, there is a risk of immediate shutdown. In one or more embodiments, the pressure threshold P is preset_fIs 300KPa (kilopascal). Alternatively, the pressure threshold P is preset_fOther suitable pressure values are set to be greater or less than 300KPa (kilopascals). At this time, the current starting operation time t is obtained_y(step S63), and the current starting up operation time length t_yAnd setting a minimum operation time t_minAnd (step S64).

As shown in fig. 3, when the current power-on operation time t is long_yLess than a set minimum operating time t_minThe time duration t of the starting operation of the compressor 111 is described_yThe set minimum operating time t has not been reached_minThe outdoor bypass electromagnetic valve 129 connected in parallel with the compressor 111 is controlled to be closed and kept at the first predetermined timePeriod t₁(step S65). A first predetermined period of time t₁Equal to the set minimum operating time t_minWith the current starting-up operation time t_yThe difference of (a). In one or more embodiments, the current boot-up run length t_yFor 3min (minutes), a minimum operating time t is set_minIs 4min (minutes), the first predetermined period of time t₁It is 1min (min). Over a first predetermined period of time t₁Thereafter, the control outdoor bypass solenoid valve 129 is turned off (step S66). At this time, the starting operation time t of the compressor 111_yEqual to the set minimum operating time t_minThe starting operation time t of the compressor 111 is described_yThe set minimum operating time period t has been reached_minThe requirements of (1). Next, step S67 is executed to detect the suction pressure P of the compressor 111_sThen the detected suction pressure P is measured_sAnd a set stop pressure P_tA comparison is made (step 68). When suction pressure P_sLess than a set shutdown pressure P_tAnd maintained for a second predetermined period of time t₂After that, the compressor 111 is controlled to stop (step S69). Wherein a shut-down pressure P is set_tLess than a predetermined pressure threshold P_fTo avoid shutdown of the compressor 111 if the outdoor bypass solenoid valve 129 has not closed. In one or more embodiments, the shutdown pressure P is set_t280KPa (kilopascal), a second predetermined time period t₂And was 20s (seconds). It will be appreciated that the shutdown pressure P is set_tThe temperature control method can be determined according to the working condition temperature of the refrigerating and freezing unit 1 and the application range of the evaporation temperature of the indoor unit 21, and a user can set the temperature according to actual needs. For example, when the working temperature of the refrigerating and freezing unit 1 is-20 ℃ to 50 ℃ and the applicable range of the evaporation temperature of the indoor unit 21 is-15 ℃ to 5 ℃, the shutdown pressure P is set_tThe value range of (A) is 250KPa to 350KPa (kilopascal), as long as the shutdown pressure P is set_tIs higher than a preset pressure threshold value P_fIs small in size. Further, a second predetermined time period t₂Other suitable times longer or shorter than 20s may also be provided.

As shown in fig. 3, when the current power-on operation time t is long_yIs more than or equal to the set minimum operation time t_minWhen the temperature of the water is higher than the set temperature,description of the suction pressure P_sFalls to a preset pressure threshold value P_fThe current starting-up operation time t of the compressor 111_yThe set minimum operating time period t has been reached_minBased on the intake pressure Ps and the set stop pressure P_tAnd controls the compressor 111 to be normally stopped as a result of the comparison. Specifically, the suction pressure P of the compressor 111 is detected_s(step 67), the detected suction pressure P is further measured_sAnd a set stop pressure P_tA comparison is made (step 68). When suction pressure P_sLess than a set shutdown pressure P_tAnd maintained for a second predetermined period of time t₂After that, the compressor 111 is controlled to stop (step S69). Wherein a shut-down pressure P is set_tLess than a predetermined pressure threshold P_f。

As shown in FIG. 3, the time duration t is when the computer is turned on_yLess than a set minimum operating time t_minWhen this occurs, the compressor 111 is controlled to enter the normal stop mode. Specifically, the suction pressure P of the compressor 111 is detected_s(step 67), the detected suction pressure P is further measured_sAnd a set stop pressure P_tA comparison is made (step 68). When suction pressure P_sLess than a set shutdown pressure P_tAnd maintained for a second predetermined period of time t₂After that, the compressor 111 is controlled to stop (step S69).

Fig. 4 is a flowchart of a control method of a refrigerating and freezing unit according to a second embodiment of the present invention. As shown in fig. 4, the control method of the refrigeration and freezing unit 1 further includes: detecting coil temperature T of indoor unit 21 of refrigerator-freezer unit 1_p(step S70), the temperature T of the coil is adjusted_pAnd setting frosting temperature T_jComparison is performed (step S71). When temperature T of coil_pGreater than or equal to the set frosting temperature T_jWhen it is determined that there is no frost formation or the possibility of frost formation is low in the indoor heat exchanger 211, the coil temperature T is repeatedly detected_pThe step (2). When temperature T of coil_pLess than the set frosting temperature T_jIn this case, the defrosting means of the refrigeration and freezing unit 1 is controlled to be turned on (step S72). It will be appreciated that when the coil temperature T is reached_pLess than the set frosting temperature T_jWhen it is, the frosting condition of the indoor heat exchanger 211 is illustratedThe condition or the possibility of frost formation is high. In order to ensure the refrigeration efficiency of the refrigeration and freezing unit 1, the defrosting component in the refrigeration and freezing unit 1 needs to be started. In one or more embodiments, the defrost component may be an electrically heated defrost component disposed on the indoor heat exchanger 211. Alternatively, the defrosting component may also be a hot defrosting bypass line 126 and a hot defrosting shutoff valve 127 (shown in fig. 1) disposed between the discharge port of the compressor 111 and the discharge port of the indoor heat exchanger 211. Over a third predetermined period of time t₃Thereafter, the defrosting means is turned off (step 73). In one or more embodiments, the third predetermined time period t₃And 30s (seconds). Alternatively, the third predetermined period of time t₃Other suitable times, longer or shorter than 30s, may be provided as long as it is ensured that the third predetermined period of time t has elapsed₃The frost layer on the rear indoor heat exchanger 211 is removed.

Fig. 5 is a flowchart of a method of controlling a refrigeration-freezing unit according to a third embodiment of the present invention. As shown in fig. 5, the control method of the refrigeration and freezing unit 1 further includes: detecting the indoor temperature T of a refrigeration and freezing unit 1_n(step S1), the indoor temperature T is adjusted_nAnd setting the starting temperature T_kComparison is performed (step S81). When indoor temperature T_nLess than a set starting temperature T_kWhen the temperature of the indoor side is lower, the requirement of the target temperature set by the user can be met, and the indoor temperature T is repeatedly detected without starting the compressor 111 to operate_nThe step (2). When indoor temperature T_nGreater than or equal to the set starting temperature T_kIf the indoor temperature is increased and the target temperature requirement set by the user cannot be met, and the compressor 111 needs to be started, step S82 is executed, i.e., the indoor solenoid valve 213 is controlled to be closed, and the outdoor bypass solenoid valve 129 is controlled to be closed. After the indoor solenoid valve 213 is closed, the suction pressure P of the compressor 111_sThe pressure of the compressor 111 can be quickly transferred from the high pressure side of the exhaust port to the low pressure side of the suction port by controlling the closing of the outdoor bypass solenoid valve 129 on the outdoor balance bypass line 128 connected in parallel with the compressor 111 while slowly rising, thereby achieving the purpose of quick pressure equalization. Detecting suction pressure P of compressor 111_s(step S83), the detected suction pressure P is used_sAnd setting the starting pressure P_kComparison is performed (step S84). When suction pressure P_sLess than a set starting pressure P_kWhen, the suction pressure P is explained_sIf the starting pressure of the compressor 111 is not reached yet, the suction pressure P of the compressor 111 is repeatedly detected_sThe step (2). When suction pressure P_sGreater than or equal to the set starting pressure P_kThen, the outdoor bypass solenoid valve 129 is controlled to be turned off, and the compressor 111 is controlled to be turned on (step S85). It will be appreciated that the starting pressure P is set_kThe temperature control method can be determined according to the working condition temperature of the refrigerating and freezing unit 1 and the application range of the evaporation temperature of the indoor unit 21, and a user can set the temperature according to actual needs. In one or more embodiments, when the working temperature of the refrigerating and freezing unit 1 is-20 ℃ to 50 ℃ and the applicable range of the evaporation temperature of the indoor unit 21 is-15 ℃ to 5 ℃, the starting pressure P is set_kThe value range of (A) is 450KPa to 650KPa (kilopascal). To prevent the suction pressure P after the compressor 111 is left standing for a long time under low temperature condition_sThe set starting pressure P can not be reached_kThe compressor 111 cannot be started, so that the starting pressure P is set when the working temperature of the refrigeration and freezing unit 1 is less than-25 DEG C_kThe value range of (A) is set to be 150KPa to 250KPa (kilopascal).

So far, the technical solutions of the present invention have been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the invention, a person skilled in the art may combine technical features from different embodiments, and may make equivalent changes or substitutions for related technical features, and such changes or substitutions will fall within the scope of the invention.