Compressor frequency control method for swimming pool heat pump system

Abstract

The invention relates to a compressor frequency control method for a swimming pool heat pump system. The compressor frequency control method specifically comprises a control method for switching a compressor to an overclocking heating mode and a subsequent control method for quitting the compressor from the overclocking heating mode. By detecting the water inlet temperature change rate, the running frequency of the compressor is increased to the overclocking gear according to the temperature change condition of the swimming pool at the moment, so that the set temperature is quickly reached; and then the heating mode of the compressor is adjusted according to the detected parameters, the environment temperature, the water inlet temperature and the accumulated heating time when the compressor works, the situation that the service life of the compressor is affected due to the fact that the pressure and the temperature of the compressor are too high in the overclocking heating mode is prevented, unnecessary energy consumption is reduced, the energy efficiency ratio of the system is increased, and more stable temperature control is provided.

Description

Technical Field

[0001] The present invention relates to the technical field of compressor operation, and in particular to a compressor frequency control method. Background Art

[0002] Variable frequency heat pump systems are widely used in the field of constant temperature swimming pools. Variable frequency heat pump technology can ensure the comfort of pool water temperature while significantly reducing the energy consumption of swimming pool heat pumps.

[0003] In the prior art, the variable frequency heat pump system divides the compressor frequency into 10 frequency gears from the lowest frequency to the highest frequency, and intelligently controls the operating frequency of the compressor according to the ambient temperature, the inlet water temperature and the target water temperature.

[0004] However, this control method has its shortcomings. When the ambient air temperature and water temperature are low, the output capacity of the variable frequency heat pump system is greatly attenuated and cannot meet the actual use requirements well, especially when the equipment is installed for the first time or at the beginning of the swimming season, which requires a longer preheating time; at the same time, the use control is performed in an all-weather environment at the preset 10 frequency levels, and the compressor frequency control method is too rough, which limits the maximum use of the variable frequency swimming pool heat pump system. Summary of the invention

[0005] Based on this, the purpose of the present invention is to overcome the defects or shortcomings of the prior art and provide a compressor frequency control method for a swimming pool heat pump system.

[0006] A compressor frequency control method for a swimming pool heat pump system comprises the following steps:

[0007] After the compressor runs for a period of time t, obtain the inlet water temperature change rate ΔT s , water inlet temperature T s 、Ambient temperature T r , if the inlet water temperature change rate ΔT s Less than the set temperature change rate threshold ΔT s_0 , and the target water temperature is set to T set With inlet water temperature T s The difference between ΔT set Greater than or equal to the target water temperature start hysteresis threshold ΔT set_q , and the ambient temperature T r Less than or equal to the ambient temperature start threshold T r_q , and the inlet water temperature T s Less than or equal to the inlet water temperature start threshold T s_q , control the compressor to switch to overclocking heating mode;

[0008] In other cases, the compressor is controlled to operate in the original heating mode.

[0009] Compared with the prior art, the compressor frequency control method for a swimming pool heat pump system described in the present invention can quickly reach the set temperature when first installed or at the beginning of the swimming season.

[0010] In one embodiment, the water inlet temperature change rate ΔT is obtained. s The method is: continuously obtain the inlet water temperature T for N cycles s , where the inlet water temperature of the first cycle is T s T s_1 , the inlet water temperature T of the Nth cycle s T s_N , then the inlet water temperature change rate ΔT s T s_N With T s_1 The difference.

[0011] In one embodiment, the temperature change rate threshold ΔT is set s_0 is 1℃; inlet water temperature T s The detection cycle time is set to 1 minute; N is a positive integer and its value is greater than 5.

[0012] In one embodiment, after the compressor switches to the overclocking heating mode, the method further includes controlling the compressor to exit the overclocking heating mode. The method is as follows: obtaining the exhaust temperature T of the compressor at the current moment d , Exhaust pressure P d , calculate the exhaust pressure P d With suction pressure P s The ratio x between them, if the exhaust temperature T at the current moment is satisfied d Greater than or equal to the exhaust temperature protection threshold T d_limt , or exhaust pressure P d Greater than or equal to the exhaust pressure protection threshold P d_limt , or the pressure ratio x is greater than or equal to the pressure ratio protection threshold X limt If any of the following conditions is met, the compressor is controlled to exit the overclocking heating mode and switch to the normal heating mode; in other cases, the compressor is controlled to continue to operate in the overclocking heating mode.

[0013] In one embodiment, after the compressor continues to operate in the overclocking heating mode, further control of the compressor exiting the overclocking heating mode is included, and the method is as follows: obtaining the current ambient temperature T r , water inlet temperature T s , if the current ambient temperature T r Greater than or equal to the ambient temperature start threshold T r_q Stop hysteresis threshold ΔT with ambient temperature r_t The sum of the inlet water temperature T s Greater than or equal to the inlet water temperature start threshold T s_qStop the return difference threshold ΔT with the inlet water temperature s_t If any one of the conditions in the sum is met, the compressor is controlled to exit the overclocking heating mode and switch to the rapid heating mode; in other cases, the compressor is controlled to continue to operate in the overclocking heating mode.

[0014] In one embodiment, after the compressor continues to operate in the overclocking heating mode, further control of the compressor exiting the overclocking heating mode is included, and the method is as follows: obtaining the cumulative heating time h and the water inlet temperature T of the compressor operating in the overclocking heating mode at the current moment s , if the cumulative heating time h is greater than the cumulative heating time threshold H, or the inlet water temperature T s Greater than or equal to the target water temperature T set Stop the return difference threshold ΔT with the target water temperature set_t If any of the above conditions are met, the compressor is controlled to exit the overclocking heating mode and switch to the conventional heating mode; in other cases, the compressor is controlled to continue to operate in the overclocking heating mode.

[0015] Compared with the prior art, the compressor frequency control method for a swimming pool heat pump system described in the present invention can quickly reach the set temperature when first installed or at the beginning of the swimming season, and keep the water temperature constant and comfortable during operation, while improving the operating reliability and service life of the unit.

[0016] For better understanding and implementation, the present invention is described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 A schematic diagram of the gear position change of a conventional heating mode involved in an embodiment of the present invention;

[0018] Figure 2 A schematic diagram of the gear position change of the rapid heating mode involved in an embodiment of the present invention;

[0019] Figure 3 is a flow chart of a control method involved in an embodiment of the present invention;

[0020] Figure 4 The figure is a general flow chart of the control method involved in the embodiment of the present invention. DETAILED DESCRIPTION

[0021] The scheme of the present invention is described in detail below with reference to the accompanying drawings.

[0022] The variable frequency heat pump system includes a compressor, a condenser, an electronic expansion valve and an evaporator connected in sequence by a refrigerant circulation pipeline, wherein the condenser is a heat exchanger for exchanging heat with the swimming pool; it also includes a first temperature sensor for detecting the ambient temperature, and a second temperature sensor for detecting the inlet water temperature of the heat pump system, and a controller, wherein the first temperature sensor, the second temperature sensor and the controller are electrically connected or communicated. The position of the first temperature sensor is not specifically limited in the present invention, and is only used to collect the ambient temperature of the variable frequency heat pump system to obtain the ambient temperature T r The second temperature sensor is arranged on the water inlet pipe of the variable frequency heat pump system to obtain the water inlet temperature T s .

[0023] Specifically, the compressor frequency of the existing variable frequency heat pump system is divided into 10 levels from F0 to F10, and the changes of each level in the conventional heating mode are as follows: Figure 1 As shown, the changes of each gear in the fast heating mode are as follows Figure 2 As shown, the present invention proposes an overclocking heating mode, which is to add several higher frequency gears to the existing compressor frequency so that the compressor works at this gear. Specifically, the higher frequency gear is set according to the actual needs of the user.

[0024] As shown in Table 1 below, the symbols, specific meanings and value ranges used in this control method are as follows:

[0025]

[0026] Table 1

[0027]

[0028] like Figure 3 to Figure 4 As shown, a compressor frequency control method for a swimming pool heat pump system according to an embodiment of the present invention comprises the following steps:

[0029] The S10 compressor operates in normal heating mode or fast heating mode and the system starts.

[0030] S20 obtains the inlet water temperature change rate ΔT s , determine the inlet water temperature change rate ΔT s Is it greater than or equal to 1℃?

[0031] If yes, maintain the current heating mode;

[0032] If not, execute S30;

[0033] Specifically, obtain the inlet water temperature change rate ΔT s The method is: continuously obtain the inlet water temperature T for 10 cycles s , where the inlet water temperature of the first cycle is Ts T s_1 , the inlet water temperature T of the 10th cycle s T s_10 , then the inlet water temperature change rate ΔT s T s_10 With T s_1 wherein a detection cycle time can be set according to demand, in this embodiment a detection cycle is set to 1 minute.

[0034] S30 obtains the current water inlet temperature Ts and the ambient temperature T r , determine whether the target water temperature T is met at the same time set The difference between the inlet water temperature Ts and the set Is it greater than or equal to the target water temperature start differential threshold ΔT? set_q , and the ambient temperature T r Less than or equal to the ambient temperature start threshold T r_q , and the inlet water temperature Ts is less than or equal to the inlet water temperature start threshold T s_q ;

[0035] If the conditions are met, the compressor is controlled to switch from the original heating mode to the overclocking heating mode, and step S40 is executed;

[0036] In other cases, the compressor still operates in the original heating mode and step S20 is executed.

[0037] S40 obtains the exhaust temperature T of the compressor at the current moment d , Exhaust pressure P d , Suction pressure P s , and calculate the exhaust pressure P d With suction pressure P s The ratio x between them is used to determine whether the exhaust temperature T at the current moment is satisfied at the same time. d Less than the exhaust temperature protection threshold T d_limt , and the exhaust pressure P d Less than the exhaust pressure protection threshold P d_limt , and the pressure ratio x is less than the pressure ratio protection threshold X limt ;

[0038] If both conditions are met, the compressor is controlled to continue to operate in the overclocking heating mode, and step S50 is executed;

[0039] If both conditions cannot be met at the same time, the compressor is controlled to exit the overclocking heating mode and switch to the normal heating mode, and step S20 is executed.

[0040] S50 obtains the current ambient temperature T r , water inlet temperature T s , determine whether the ambient temperature T rLess than the ambient temperature start threshold T r_q Stop hysteresis threshold ΔT with ambient temperature r_t The sum of the inlet water temperature T s Less than the inlet water temperature start threshold T s_q Stop the return difference threshold ΔT with the inlet water temperature s_t sum;

[0041] If both conditions are met, the compressor is controlled to continue to operate in the overclocking heating mode, and step S60 is executed;

[0042] If both conditions cannot be met at the same time, the compressor is controlled to exit the overclocking heating mode and switch to the rapid heating mode, and step S20 is executed.

[0043] S60 obtains the cumulative heating time h and the water inlet temperature T of the compressor running in the overclocking heating mode at the current moment. s , determine whether the cumulative heating time h is less than the cumulative heating time threshold H, and the inlet water temperature T s Less than target water temperature T set Stop the return difference threshold ΔT with the target water temperature set_t difference;

[0044] If both conditions are met, the compressor is controlled to continue to operate in the overclocking heating mode, and step S40 is executed;

[0045] If both conditions cannot be met at the same time, the compressor is controlled to exit the overclocking heating mode and switch to the normal heating mode, and step S20 is executed.

[0046] Compared with the prior art, the control method provided by the present invention has the following technical effects:

[0047] 1) When the swimming pool heat pump unit is first installed or the swimming season begins, the internal water temperature is low. By detecting the rate of change of the inlet water temperature, the operating frequency of the compressor is increased to the overclocking position according to the temperature change of the swimming pool at this time, so as to quickly reach the set temperature;

[0048] 2) When the compressor enters the overclocking heating mode, the heating mode of the compressor is adjusted according to the detection results of various parameters of the compressor during operation to prevent the compressor from having excessive pressure and temperature in the overclocking heating mode, which may affect its life;

[0049] 3) Subsequently, by adjusting the working mode of the compressor according to the ambient temperature and the inlet water temperature, unnecessary energy consumption can be reduced and the energy efficiency ratio of the system can be improved;

[0050] 4) In addition, in order to ensure system efficiency while avoiding overheating or excessive wear of the compressor, and at the same time ensuring that the inlet water temperature can reach or approach the target water temperature. By controlling the cumulative heating time and the inlet water temperature, the system can switch between different working modes to adapt to current working conditions and needs, which helps to improve energy efficiency, extend equipment life, and provide more stable temperature control.

[0051] The terms used in the embodiments of the present application are only for the purpose of describing specific embodiments, and are not intended to limit the embodiments of the present application. The singular forms of "a", "said" and "the" used in the embodiments of the present application and the claims are also intended to include plural forms, unless the context clearly indicates other meanings. It should also be understood that, unless otherwise specified, "multiple" refers to two or more; the terms "first", "second", "third", etc. are only used to distinguish, rather than to describe a specific order or sequence, and cannot be understood as indicating or implying relative importance. The term "and / or" used herein refers to and includes any or all possible combinations of one or more associated listed items. When the above description relates to the drawings, unless otherwise indicated, the same numbers in different drawings represent the same or similar elements. In the description of the present application, for those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0052] The above-mentioned embodiments only express several implementation methods of the present invention, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the invention patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention.

Claims

1. A compressor frequency control method for a swimming pool heat pump system, characterized in that: The following steps are involved: After the compressor runs for a period of time t, obtain the inlet water temperature change rate ΔT s , water inlet temperature T s 、Ambient temperature T r : If the inlet water temperature change rate ΔT s Less than the set temperature change rate threshold ΔT s_0 , and the target water temperature is set to T set With inlet water temperature T s The difference between ΔT set Greater than or equal to the target water temperature start hysteresis threshold ΔT set_q , and the ambient temperature T r Less than or equal to the ambient temperature start threshold T r_q , and the inlet water temperature T s Less than or equal to the inlet water temperature start threshold T s_q , control the compressor to switch to overclocking heating mode; In other cases, the compressor is controlled to operate in the original heating mode.

2. The compressor frequency control method for a swimming pool heat pump system according to claim 1, characterized in that: Get the inlet water temperature change rate ΔT s The method comprises the following steps: Continuously obtain the inlet water temperature T for N cycles s , where the inlet water temperature of the first cycle is T s T s_1 , the inlet water temperature T of the Nth cycle s T s_N , then the inlet water temperature change rate ΔT s T s_N With T s_1 The difference.

3. The compressor frequency control method for a swimming pool heat pump system according to claim 2, characterized in that: Set the temperature change rate threshold ΔT s_0 is 1℃; inlet water temperature T s The detection cycle time is set to 1 minute; N is a positive integer and its value is greater than 5.

4. The compressor frequency control method for a swimming pool heat pump system according to claim 2, characterized in that: After the compressor switches to the overclocking heating mode, the method also includes controlling the compressor to exit the overclocking heating mode, as follows: Get the current compressor exhaust temperature T d , if the exhaust temperature T at the current moment is satisfied d Greater than or equal to the exhaust temperature protection threshold T d_limt , control the compressor to exit the overclocking heating mode; In other cases, the compressor is controlled to continue running in overclocking heating mode.

5. The compressor frequency control method for a swimming pool heat pump system according to claim 2, characterized in that: After the compressor switches to the overclocking heating mode, the method also includes controlling the compressor to exit the overclocking heating mode, as follows: Get the exhaust pressure P of the compressor at the current moment d , if the exhaust pressure P at the current moment is satisfied d Greater than or equal to the exhaust pressure protection threshold P d_limt , control the compressor to exit the overclocking heating mode; In other cases, the compressor is controlled to continue running in overclocking heating mode.

6. The compressor frequency control method for a swimming pool heat pump system according to claim 2, characterized in that: After the compressor switches to the overclocking heating mode, the method also includes controlling the compressor to exit the overclocking heating mode, as follows: Get the exhaust pressure P of the compressor at the current moment d , Suction pressure P s , calculate the exhaust pressure P d With suction pressure P s If the current pressure ratio x is greater than or equal to the pressure ratio protection threshold X limt , control the compressor to exit the overclocking heating mode; In other cases, the compressor is controlled to continue running in overclocking heating mode.

7. The compressor frequency control method for a swimming pool heat pump system according to claims 4-6, characterized in that: After the compressor exits the overclocking heating mode, it switches to the normal heating mode.

8. The compressor frequency control method for a swimming pool heat pump system according to claims 4-6, characterized in that: After the compressor continues to operate in the overclocking heating mode, further control of the compressor exiting the overclocking heating mode is included as follows: Get the current ambient temperature T r , water inlet temperature T s , if the current ambient temperature T r Greater than or equal to the ambient temperature start threshold T r_q Stop hysteresis threshold ΔT with ambient temperature r_t The sum of the inlet water temperature T s Greater than or equal to the inlet water temperature start threshold T s_q Stop the return difference threshold ΔT with the inlet water temperature s_t Any condition in the sum controls the compressor to exit the overclocking heating mode and switch to the fast heating mode; In other cases, the compressor is controlled to continue running in overclocking heating mode.

9. The compressor frequency control method for a swimming pool heat pump system according to claim 8, characterized in that: After the compressor continues to operate in the overclocking heating mode, it also includes further control of the compressor exiting the overclocking heating mode, as follows: Obtain the cumulative heating time h of the compressor running in the overclocking heating mode at the current moment. If the cumulative heating time h is greater than or equal to the cumulative heating time threshold H, control the compressor to exit the overclocking heating mode and switch to the normal heating mode; In other cases, the compressor is controlled to continue running in overclocking heating mode.

10. The compressor frequency control method for a swimming pool heat pump system according to claim 8, characterized in that: After the compressor continues to operate in the overclocking heating mode, it also includes further control of the compressor exiting the overclocking heating mode, as follows: Get the current inlet water temperature T s , if the inlet water temperature T s Greater than or equal to the target water temperature T set Stop the return difference threshold ΔT with the target water temperature set_t The difference between the values ​​of the heating and cooling units is controlled to control the compressor to exit the overclocking heating mode and switch to the normal heating mode; In other cases, the compressor is controlled to continue running in overclocking heating mode.

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