Variable frequency heat pump unit and heat dissipation control method

Abstract

The invention discloses a variable frequency heat pump unit and a heat dissipation control method.The variable frequency heat pump unit comprises a refrigerant circulation loop and a variable frequency driving module, the refrigerant circulation loop is formed by connecting a compressor, a heat exchanger combination, a liquid storage device and a gas-liquid separator, and the variable frequency driving module is provided with a heat dissipation pipeline; the outlet end of the heat dissipation pipeline is connected to the air suction side of the compressor, the inlet end of the heat dissipation pipeline communicates with a liquid storage cavity of the liquid storage device through a first branch and a second branch, the first branch is provided with a cooling pipe section located in the gas-liquid separator, a first throttling device is installed on the outlet side of the cooling pipe section, and the second branch is located outside the gas-liquid separator. The second branch is provided with a second throttling device; the first throttling device and the second throttling device are adjustable in opening degree and work cooperatively. The liquid refrigerant in the liquid storage device is led out to dissipate heat of the variable frequency driving module, the influence of heat dissipation on main path circulation is reduced, and the heat dissipation efficiency and the unit performance can be both considered.

Description

Technical Field

[0001] The present invention relates to the technical field of heat pump units, and in particular to a variable frequency heat pump unit and a heat dissipation control method. Background Art

[0002] Variable frequency units have become mainstream equipment in the HVAC field by virtue of their ability to achieve terminal load matching and low-load efficient operation through frequency regulation. However, with technological upgrades and expansion of application scenarios, the heat dissipation problems of their core components and the difficulties in multi-mode flow management have become increasingly prominent, restricting the performance of the units under different working conditions.

[0003] In variable-frequency units, the IPM (Intelligent Power Module) serves as the core electronic control device driving the compressor, and its heat dissipation performance directly affects the compressor's energy efficiency and operational stability. Currently, the industry generally adopts air cooling or refrigerant cooling solutions to address IPM heating issues: air cooling relies on convection heat transfer between the condenser's ambient airflow and the cooling fins. However, when the outdoor ambient temperature is high, the air temperature after passing through the condenser rises significantly, causing the IPM's heat dissipation efficiency to drop significantly. Due to insufficient heat dissipation, the compressor is forced to limit its operating frequency. Refrigerant cooling, which exchanges heat through contact between low-temperature liquid refrigerant and the IPM, has more stable heat dissipation characteristics. However, in high-temperature environments, the refrigerant's own temperature rises, reducing the temperature difference between it and the IPM and weakening the heat dissipation effect. Furthermore, the risk of high-pressure refrigerant leakage increases with increasing piping complexity.

[0004] At the same time, in order to achieve heat recovery or four-pipe control functions (such as meeting cooling and heating needs at the same time), new variable frequency units often need to switch the refrigerant flow path according to different modes (cooling, heating, and heat recovery), and after switching modes, the refrigerant flowing out of the condenser needs to pass through the IPM. This design leads to an increase in the length of the system pipeline, an increase in the number of elbows, and an increase in the refrigerant flow resistance (significant pressure loss along the way). It not only reduces the supercooling degree, but also makes some refrigerants unable to effectively participate in heat exchange due to the excessive length of the pipeline, resulting in no heat exchange loss; when switching multi-mode flow paths, the refrigerant needs to be frequently distributed to different heat exchangers, and some refrigerants occupy the evaporator space due to redundant flow path design, resulting in a reduction in the effective heat exchange area of ​​the evaporator and a reduction in the heat exchange efficiency of the unit; at the same time, improper refrigerant flow control will directly affect the stability of the main circuit and aggravate the instability of IPM heat dissipation.

[0005] Therefore, how to design a variable frequency heat pump unit and a heat dissipation control method that can take into account both heat dissipation efficiency and unit performance is a technical problem that the industry urgently needs to solve. Summary of the Invention

[0006] In order to solve the defects of unstable IPM heat dissipation and low unit performance in existing heat pump units, the present invention proposes a variable frequency heat pump unit and a heat dissipation control method. The liquid refrigerant in the liquid reservoir is drawn out to dissipate heat for the variable frequency drive module, and the gaseous refrigerant after heat dissipation is returned to the suction side of the compressor, thereby reducing the impact of heat dissipation on the main circulation, effectively reducing the harmful pressure drop of the refrigerant circulation loop and fully utilizing the evaporator, thereby improving the unit performance.

[0007] The technical solution adopted by the present invention is to design a variable frequency heat pump unit, including: a refrigerant circulation loop and a variable frequency drive module, the refrigerant circulation loop is formed by connecting a compressor, a heat exchanger combination, a liquid reservoir, and a gas-liquid separator, the heat exchanger combination includes three heat exchangers, and at least two heat exchangers participate in the refrigerant circulation of the refrigerant circulation loop; the variable frequency drive module is equipped with a heat dissipation pipeline, the outlet end of the heat dissipation pipeline is connected to the suction side of the compressor, and the inlet end of the heat dissipation pipeline is connected to the liquid storage cavity of the liquid reservoir through a first branch and a second branch respectively, the first branch is provided with a cooling pipe section located inside the gas-liquid separator, and a first throttling device is installed on the outlet side of the cooling pipe section, the second branch is located outside the gas-liquid separator, and a second throttling device is installed on the second branch; wherein the opening of the first throttling device and the second throttling device are adjustable and work in coordination.

[0008] Furthermore, the three heat exchangers are the first heat exchanger, the second heat exchanger and the third heat exchanger, and the exhaust side of the compressor can be switched to connect to the first end of any heat exchanger; the second end of the first heat exchanger is connected to the liquid reservoir through the first outlet pipe and the first inlet pipe respectively; the second end of the second heat exchanger is connected to the liquid reservoir through the second outlet pipe; the second end of the third heat exchanger is connected to the liquid reservoir through the third outlet pipe and the third inlet pipe respectively; wherein each outlet pipe is equipped with a control valve allowing refrigerant to flow to the liquid reservoir, and each inlet pipe is equipped with a throttling device.

[0009] Furthermore, the second end of the second heat exchanger is also connected to the liquid reservoir through a second inlet pipe.

[0010] Furthermore, the first heat exchanger is an air-conditioning water heat exchanger, the second heat exchanger is a hot water heat exchanger, and the third heat exchanger is an outdoor heat exchanger. The working modes of the variable frequency heat pump unit include at least one of a cooling mode, a heating mode, a hot water mode, a cooling and heating water mode, and a heating and heating water mode.

[0011] In some embodiments, the first throttling device and the second throttling device are both electronic expansion valves.

[0012] The present invention also proposes a heat dissipation control method, which is applied to the above-mentioned variable frequency heat pump unit. The heat dissipation control method includes: Obtain the operating mode of the variable frequency heat pump unit and the heat exchange medium temperature on the condensing side of the refrigerant circulation loop; Compare the temperature of the heat exchange medium on the condensing side with the set inflection point temperature corresponding to the current working mode; If the temperature of the heat exchange medium on the condensing side is greater than the set inflection point temperature, the first heat dissipation strategy based on the regulation of the first throttling device is executed; If the temperature of the heat exchange medium on the condensing side is less than the set inflection point temperature, the second heat dissipation strategy based on the regulation of the second throttling device is executed.

[0013] Furthermore, the first heat dissipation strategy includes: Get the actual temperature of the variable frequency drive module; When the actual temperature is ≥ the set temperature B, increase the opening of the first throttling device; When the actual temperature is less than the set temperature B, the first throttling device is controlled to maintain the set initial opening, and the opening of the second throttling device is adjusted in a set slow manner.

[0014] Furthermore, the second heat dissipation strategy includes: Get the actual temperature of the variable frequency drive module; When the actual temperature is greater than or equal to the set temperature B1, the opening of the second throttling device is increased. If the second throttling device is opened to the maximum opening, the opening of the first throttling device is increased. When the actual temperature is less than or equal to the set temperature A1, the first throttling device is closed and the opening of the second throttling device is adjusted according to the set slow speed mode; When the set temperature A1 is less than the actual temperature and less than the set temperature B1, the first throttling device is controlled to maintain the current opening, and the opening of the second throttling device is adjusted in a set fast manner.

[0015] Furthermore, setting the slow mode includes: Get the actual superheat of the heat dissipation pipeline; When the actual superheat degree is greater than the set superheat degree △C1, the opening degree of the second throttling device is increased at each interval of the set time E1; When the actual superheat is less than the set superheat △D1, the opening of the second throttling device is reduced at each set time interval E1; When the set temperature △D1<actual temperature<set temperature △C1, the opening of the second throttling device is maintained.

[0016] Furthermore, setting up quick methods includes: Get the actual superheat of the heat dissipation pipeline; When the actual superheat degree is greater than the set superheat degree △C2, the opening degree of the second throttling device is increased at each set interval E2; When the actual superheat is less than the set superheat △D2, the opening of the second throttling device is reduced at each set time interval E2; When the set temperature △D2 < actual temperature < set temperature △C2, maintain the opening of the second throttling device; Here, the set time E2 is less than the set time E1.

[0017] Compared with the prior art, the present invention has at least one of the following beneficial effects: 1. Connect the heat dissipation pipeline of the variable frequency drive module between the liquid storage chamber of the liquid reservoir and the suction side of the compressor, draw out the liquid refrigerant accumulated in the liquid reservoir to dissipate heat for the variable frequency drive module, and then return the gaseous refrigerant after heat dissipation to the suction side of the compressor, thereby reducing the impact of heat dissipation on the main circuit, effectively reducing the harmful pressure drop of the refrigerant circulation loop, fully utilizing the evaporator, and improving the performance of the unit; 2. The heat dissipation pipeline is connected to the liquid storage chamber of the liquid reservoir through two branches. One branch does not pass through the gas-liquid separator, and the liquid refrigerant directly enters the heat dissipation pipeline to dissipate heat for the variable frequency drive module. The other branch passes through the gas-liquid separator for cooling, thereby improving the heat dissipation effect of the variable frequency drive module. The two branches can be flexibly adjusted to reduce the temperature fluctuation of the variable frequency drive module and improve the stability of the unit. 3. Design inflection point temperatures for different operating modes. By precisely matching the temperature characteristics of the heat exchange medium on the condensing side of each mode, dynamically adjust the heat dissipation strategy to solve the adaptability issues of traditional single heat dissipation solutions under high / low temperature conditions, ensure the temperature stability of the variable frequency drive module in all scenarios, and significantly enhance the reliability and energy efficiency of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The present invention is described in detail below with reference to the embodiments and accompanying drawings, in which: Figure 1 This is a connection diagram of a preferred embodiment of the variable frequency heat pump unit of the present invention; Figure 2 This is a connection diagram of a feasible embodiment of the variable frequency heat pump unit of the present invention; Figure 3 Schematic diagram of the refrigerant flow in the refrigeration mode of the present invention; Figure 4 Schematic diagram of the refrigerant flow in the heating mode of the present invention; Figure 5 Schematic diagram of the refrigerant flow direction in the hot water mode of the present invention; Figure 6 Schematic diagram of the refrigerant flow direction in the cooling and heating water mode of the present invention; Description of the drawings: 1. Compressor; 2. First heat exchanger; 3. Second heat exchanger; 4. Third heat exchanger; 5. Liquid reservoir; 6. Gas-liquid separator; 7. First one-way valve; 8. Second one-way valve; 9. Third one-way valve; 10. Refrigeration throttling device; 11. Heating throttling device; 12. Defrosting throttling device; 13. First four-way valve; 14. Second four-way valve; 15. Frequency conversion drive module; 16. First throttling device; 17. Second throttling device. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] like Figure 1 、 2 As shown, the variable-frequency heat pump unit proposed in the present invention includes, but is not limited to, a heat recovery heat pump unit. A variable-frequency heat pump unit includes variable-frequency power components (e.g., a variable-frequency compressor and a variable-frequency fan), which are controlled by a variable-frequency drive module 15. This variable-frequency drive module 15 includes power switching devices (e.g., an IPM). During operation, the variable-frequency drive module 15 generates significant heat load due to power loss. Continuous heat dissipation is required to maintain its operating temperature within an acceptable range to ensure the long-term operational stability of the heat pump unit.

[0021] Specifically, the variable frequency heat pump unit includes a refrigerant circulation loop and a variable frequency drive module 15. The refrigerant circulation loop is formed by connecting a compressor 1, a heat exchanger assembly, a liquid reservoir 5, and a gas-liquid separator 6. The heat exchanger assembly includes three heat exchangers, and at least two heat exchangers participate in the refrigerant circulation of the refrigerant circulation loop. By designing the pipeline connection structure within the unit, the compressor 1 can be connected to the liquid reservoir 5 and any two heat exchangers to form a refrigerant circulation loop. The refrigerant flowing out of the condenser in the refrigerant circulation loop always passes through the liquid reservoir 5 before flowing to the evaporator. The gas-liquid separator 6 is connected to the intake side of the compressor 1. The variable frequency drive module 15 is equipped with a heat dissipation pipeline. The inlet end of the heat dissipation pipeline is connected to the liquid storage chamber of the liquid reservoir 5, and the outlet end of the heat dissipation pipeline is connected to the intake side of the compressor 1. A throttling device is also provided at the inlet end of the heat dissipation pipeline.

[0022] This design utilizes the latent heat of phase change of the low-temperature liquid refrigerant in the liquid reservoir 5, combined with a throttling device to dynamically adjust the refrigerant flow rate, to achieve efficient heat dissipation for the variable frequency drive module (IPM) 15. This avoids the attenuation problem of traditional air cooling / refrigerant cooling in high-temperature environments, while also preventing incomplete evaporation or pressure fluctuations caused by excessive refrigerant through throttling. It also reduces the impact of heat dissipation on the main circuit, effectively lowering harmful pressure drops in the refrigerant circulation loop and fully utilizing the evaporator. This reduces energy consumption, simplifies system structure, and improves IPM temperature stability and unit reliability under all operating conditions.

[0023] Specifically, the inlet end of the heat dissipation pipeline is connected to the liquid storage chamber of the liquid reservoir 5 through a first branch and a second branch, respectively. The first branch is provided with a cooling pipe section located inside the gas-liquid separator 6. The outlet side of the cooling pipe section is installed with a first throttling device 16. The liquid refrigerant passes through the cooling pipe section for cooling, thereby improving the heat dissipation effect on the variable frequency drive module 15. The second branch is located outside the gas-liquid separator 6 and is installed with a second throttling device 17. The liquid refrigerant does not pass through the gas-liquid separator 6, and directly enters the heat dissipation pipeline to perform conventional heat dissipation on the variable frequency drive module 15.

[0024] Since the temperature of the heat exchange medium on the condensing side is different in each mode, the temperature of the refrigerant sent to the liquid reservoir 5 fluctuates, and the heat dissipation effect of the variable frequency drive module will change. Therefore, the preferred solution is to design the first branch and the second branch at the same time, and use the two branches to flexibly adjust the refrigerant amount and refrigerant temperature, reduce the temperature fluctuation of the variable frequency drive module 15, and improve the stability of the unit.

[0025] For ease of understanding, the three heat exchangers are the first heat exchanger 2, the second heat exchanger 3 and the third heat exchanger 4. The first end and the second end of each heat exchanger have been marked on the connection diagram of the variable frequency heat pump system, with the first end being "①" and the second end being "②".

[0026] The exhaust side of the compressor 1 can be switched to connect to the first end of any heat exchanger. The second end of the first heat exchanger 2 is connected to the liquid reservoir 5 through the first outlet pipe and the first inlet pipe respectively. The second end of the second heat exchanger 3 is connected to the liquid reservoir 5 through the second outlet pipe. The second end of the third heat exchanger 4 is connected to the liquid reservoir 5 through the third outlet pipe and the third inlet pipe respectively. Each outlet pipe is equipped with a control valve allowing the refrigerant to flow to the liquid reservoir 5. The first inlet pipe is equipped with a refrigeration throttling device 10, and the third inlet pipe is equipped with a heating throttling device 11. The on-off state of the inlet pipe in which it is located is controlled by the throttling device, and the outlet pipe and the inlet pipe both extend into the liquid storage cavity of the liquid reservoir 5.

[0027] When the compressor 1 is connected to the first end ① of a heat exchanger, the heat exchanger acts as a condenser, and the second end ② of the heat exchanger is the outlet side of the condenser. The refrigerant flowing out of the second end ② can enter the liquid reservoir 5 through the outlet pipe and the control valve. The liquid refrigerant in the liquid reservoir 5 is then sent into the evaporator through the inlet pipe and the throttling device under pressure.

[0028] This design can flexibly switch the refrigerant flow direction within the refrigerant circulation loop to meet different user needs. It controls the refrigerant distribution status of the heat exchanger through the throttling device, deeply simplifies the system structure of the unit, reduces the length and complexity of the system pipeline, reduces the refrigerant flow resistance, and has little heat exchange loss, thereby improving the heat exchange efficiency of the unit.

[0029] In addition, the control valve mentioned above can be a solenoid valve with switchable switching state, or a one-way valve. The control valve of the first heat exchanger 2 is the first one-way valve 7, the control valve of the second heat exchanger 3 is the second one-way valve 8, and the control valve of the third heat exchanger 4 is the third one-way valve 9. The one-way conduction characteristics of the one-way valve are used to ensure that the refrigerant can only flow from the heat exchanger to the liquid reservoir 5, avoiding the reverse flow of the refrigerant when switching between different modes, resulting in system pressure disorder or decreased efficiency. No additional electrical control signal is required, reducing the complexity of valve adjustment.

[0030] On this basis, to further optimize the variable frequency heat pump unit, the second end of the second heat exchanger 3 is connected to the liquid reservoir 5 via a second inlet pipe. The second inlet pipe extends into the liquid storage chamber of the liquid reservoir 5. The second inlet pipe is also equipped with a defrost throttling device 12, which controls the on / off state of the second inlet pipe. The second inlet pipe is connected when the third heat exchanger 4 functions as a condenser and the second heat exchanger 3 functions as an evaporator (i.e., during the defrost process of the third heat exchanger 4, the second heat exchanger 3 participates in the refrigerant circulation). Both the first and third inlet pipes are closed.

[0031] This design allows for the use of a second inlet pipe to connect the second and third heat exchangers 3 and 4 when defrosting the third heat exchanger 4. This allows the high-temperature refrigerant discharged from the compressor 1 to defrost the third heat exchanger 4, and then delivers the refrigerant from the third heat exchanger 4 to the liquid reservoir 5 before being fed back into the second heat exchanger 3 through the second inlet pipe. This provides the heat pump unit with increased flexibility and improved environmental adaptability. For example, in hot water mode (with the second heat exchanger 3 acting as the condenser and the third heat exchanger 4 acting as the evaporator), if the third heat exchanger 4 requires defrosting during hot water preparation, the refrigerant flow direction can be adjusted, connecting the second inlet pipe and disconnecting the first and second inlet pipes, allowing the refrigerant circulation loop to execute a defrost cycle.

[0032] Based on the above connection structure, the first heat exchanger 2 is an air-conditioning water heat exchanger, the second heat exchanger 3 is a hot water heat exchanger, and the third heat exchanger 4 is an outdoor heat exchanger. The working modes of the variable frequency heat pump unit include cooling mode, heating mode, hot water mode, cooling and heating water mode, and heating and heating water mode. The following details the operating status of the three heat exchangers in different working modes.

[0033] like Figure 3 As shown, when the variable frequency heat pump unit operates in cooling mode, the first heat exchanger 2 serves as an evaporator, the third heat exchanger 4 serves as a condenser, the second heat exchanger 3 does not participate in the refrigerant circulation, the exhaust side of the compressor 1 is connected to the first end of the third heat exchanger 4, and the refrigerant flow direction of the refrigerant circulation loop is compressor 1 → third heat exchanger 4 → liquid reservoir 5 → refrigeration throttling device → first heat exchanger 2 → return to compressor 1.

[0034] like Figure 4As shown, when the variable frequency heat pump unit operates in heating mode, the first heat exchanger 2 serves as a condenser, the third heat exchanger 4 serves as an evaporator, the second heat exchanger 3 does not participate in the refrigerant circulation, the exhaust side of the compressor 1 is connected to the first end of the first heat exchanger 2, and the refrigerant flow direction of the refrigerant circulation loop is compressor 1 → first heat exchanger 2 → liquid reservoir 5 → heating throttling device 11 → third heat exchanger 4 → return to compressor 1.

[0035] like Figure 5 As shown, when the variable frequency heat pump unit operates in hot water mode, the second heat exchanger 3 serves as a condenser, the third heat exchanger 4 serves as an evaporator, the first heat exchanger 2 does not participate in the refrigerant circulation, the exhaust side of the compressor 1 is connected to the first end of the second heat exchanger 3, and the refrigerant flow direction of the refrigerant circulation loop is compressor 1 → second heat exchanger 3 → liquid reservoir 5 → heating throttling device 11 → third heat exchanger 4 → return to compressor 1.

[0036] like Figure 6 As shown, when the variable frequency heat pump unit operates in the cooling and heating water mode (heat recovery mode), the first heat exchanger 2 serves as the evaporator, the second heat exchanger 3 serves as the condenser, the third heat exchanger 4 does not participate in the refrigerant circulation, the exhaust side of the compressor 1 is connected to the first end of the second heat exchanger 3, and the refrigerant flow direction of the refrigerant circulation loop is compressor 1 → second heat exchanger 3 → liquid reservoir 5 → refrigeration throttling device 10 → first heat exchanger 2 → back to compressor 1.

[0037] When the variable frequency heat pump unit operates in heating water mode, the third heat exchanger 4 acts as an evaporator, and the condenser is determined according to the priority of heating and hot water. If heating is the priority, the heat pump unit first works in the heating state (see Figure 4 ), the first heat exchanger 2 is a condenser, and the second heat exchanger 3 does not participate in the refrigerant cycle; if hot water is the priority, the heat pump unit will first work in the hot water state (see Figure 5 ), the second heat exchanger 3 functions as a condenser, and the first heat exchanger 2 does not participate in the refrigerant circulation. In this mode, after the current function reaches the shutdown condition, it determines whether another function meets the startup condition. If so, it starts operating in that function. For example, if heating is prioritized, after the heating function reaches the shutdown condition, it determines whether the hot water function meets the startup condition. If so, it starts operating in that function until the hot water function's shutdown condition is met.

[0038] This design integrates multiple heat exchangers for air conditioning water, hot water, and outdoor heat exchangers into the heat pump unit. The type and number of operating modes configured for the heat pump system can be selected based on the needs of the application scenario. The heat of the refrigerant can also be recovered for heating domestic hot water / heating, achieving cascaded energy utilization and improving the unit's energy efficiency.

[0039] In the preferred embodiment, the working mode of the heat pump unit includes the five working modes mentioned above. In order to switch to different working modes more accurately and reliably, the compressor 1 is connected to the three heat exchangers through two four-way valves. Figure 1 、 2 As shown, specifically, the D end of the first four-way valve 13 is connected to the exhaust side of the compressor 1, the E end is connected to the first end of the first heat exchanger 2, the S end is connected to the suction side of the compressor 1, and the C end is connected to the D end of the second four-way valve 14; the C end of the second four-way valve 14 is connected to the first end of the third heat exchanger 4, the E end is connected to the first end of the second heat exchanger 3, and the S end is connected to the suction side of the compressor 1.

[0040] It should be pointed out that the throttling device in this article is an electronic expansion valve or a solenoid valve and a capillary tube connected in series. In order to achieve precise control of the refrigerant flow, the first throttling device 16, the second throttling device 17, the refrigeration throttling device 10, and the heating throttling device 11 are all electronic expansion valves.

[0041] In order to achieve better heat dissipation effect, the present invention also proposes a heat dissipation control method, designs inflection point temperatures for different working modes, and dynamically adjusts the heat dissipation strategy by accurately matching the temperature characteristics of the heat exchange medium on the condensing side of each mode. This solves the adaptability problem of traditional single heat dissipation solutions under high / low temperature conditions, ensures the temperature stability of the variable frequency drive module in all scenarios, and significantly enhances the reliability and energy efficiency of the unit.

[0042] like Figure 1 As shown, the control logic of the heat dissipation control method is as follows: Obtain the operating mode of the variable frequency heat pump unit and the heat exchange medium temperature on the condensing side of the refrigerant circulation loop; Compare the temperature of the heat exchange medium on the condensing side with the set inflection point temperature corresponding to the current working mode; If the temperature of the heat exchange medium on the condensing side is greater than the set inflection point temperature, it means that the high-pressure refrigerant temperature is high, and the heat dissipation effect on the variable frequency drive module is poor. The first heat dissipation strategy based on the adjustment of the first throttling device 16 is implemented, and the heat dissipation is actively enhanced through the cooling effect of the first branch. If the temperature of the heat exchange medium on the condensing side is less than the set inflection point temperature, the second heat dissipation strategy based on the adjustment of the second throttling device 17 is executed, and the variable frequency drive module is subjected to conventional heat dissipation through the second branch or assisted in maintaining heat dissipation through the first branch.

[0043] It should be understood that the condensing-side heat exchange medium temperature refers to the temperature of the heat exchange medium exchanging heat with the refrigerant in the condenser. If the condenser is an air conditioning water heat exchanger or a hot water heat exchanger (typically a shell-and-tube heat exchanger), the condensing-side heat exchange medium is water, i.e., the condensing-side heat exchange medium temperature is the water temperature. If the condenser is an outdoor heat exchanger (typically a finned heat exchanger), the condensing-side heat exchange medium is air, i.e., the condensing-side heat exchange medium temperature is the ambient temperature. In addition, each mode is equipped with a corresponding set inflection point temperature to distinguish between high-temperature and low-temperature operating conditions, thereby enabling more accurate dynamic adjustment of the cooling strategy.

[0044] Specifically, in some preferred embodiments of the present invention, the first heat dissipation strategy includes: Obtaining the actual temperature of the variable frequency drive module 15; When the actual temperature is greater than or equal to the set temperature B, it indicates that the temperature of the variable frequency drive module is too high and the refrigerant flow needs to be increased, so the opening of the first throttling device 16 is increased, for example, by 10B every 10 seconds; When the actual temperature is less than the set temperature B, it indicates that the temperature of the variable frequency drive module is moderate. The first throttling device 16 is controlled to maintain the set initial opening, and the opening of the second throttling device 17 is adjusted in a set slow manner to supplement the heat dissipation.

[0045] This design can achieve precise heat dissipation under high-temperature conditions, quickly increase the refrigerant flow when the IPM temperature is high, enhance the heat dissipation capacity, and specifically solve the module overheating problem caused by insufficient refrigerant heat dissipation under high temperature; when the IPM temperature is moderate, maintain the initial opening of the first throttling device 16, and only supplement the heat dissipation through the second throttling device 17, balancing the heat dissipation efficiency and unit reliability.

[0046] In some preferred embodiments of the present invention, the second heat dissipation strategy includes: Get the actual temperature of the variable frequency drive module; When the actual temperature is greater than or equal to the set temperature B1, it indicates that the temperature of the variable frequency drive module 15 is too high, and the refrigerant flow needs to be increased, and the opening of the second throttling device 17 needs to be increased. If the second throttling device 17 is opened to the maximum opening, the opening of the first throttling device 16 needs to be increased. When the actual temperature is less than or equal to the set temperature A1, it indicates that the temperature of the variable frequency drive module 15 is too low, and the first throttling device 16 is closed, and the opening of the second throttling device 17 is adjusted in a set slow mode, and the variable frequency drive module 15 is cooled normally through the second branch; When the set temperature A1 is less than the actual temperature and less than the set temperature B1, it indicates that the temperature of the variable frequency drive module 15 is moderate. The first throttling device 16 is controlled to maintain the current opening, and the opening of the second throttling device 17 is adjusted in a set fast manner to assist the first branch in heat dissipation through the second branch.

[0047] This design can achieve precise heat dissipation under low-temperature conditions, and adjust the layers according to the actual temperature of the IPM to achieve a precise match between the heat dissipation and the heat load, avoiding both insufficient and excessive heat dissipation, and ensuring stable IPM temperature.

[0048] Based on the above heat dissipation strategy, in some feasible embodiments of the present invention, setting the slow mode includes: Obtain the actual superheat of the heat dissipation pipeline, that is, the temperature difference between the outlet and inlet of the heat dissipation pipeline; When the actual superheat degree is greater than the set superheat degree ΔC1, it indicates that the heat dissipation load of the variable frequency drive module 15 is large and the refrigerant flow rate needs to be increased. The opening of the second throttling device 17 is increased at each set interval E1. When the actual superheat is less than the set superheat ΔD1, it indicates that the heat dissipation load of the variable frequency drive module 15 is small and the refrigerant flow rate needs to be reduced. The opening of the second throttling device 17 is closed at each set time interval E1. When the set temperature ΔD1 < the actual temperature < the set temperature ΔC1, it indicates that the heat dissipation load of the variable frequency drive module 15 is moderate, and the current refrigerant flow rate is maintained, and the opening of the second throttling device 17 is maintained.

[0049] This design reduces the adjustment frequency through a longer setting time, thereby reducing the energy loss caused by frequent valve operation. It can maintain basic heat dissipation requirements while avoiding the decrease in unit stability due to overly sensitive adjustment. It is suitable for scenarios where the heat dissipation load changes smoothly.

[0050] In some feasible embodiments of the present invention, setting the quick mode includes: Obtain the actual superheat of the heat dissipation pipeline, that is, the temperature difference between the outlet and inlet of the heat dissipation pipeline; When the actual superheat degree is greater than the set superheat degree ΔC2, it indicates that the heat dissipation load of the variable frequency drive module 15 is large and the refrigerant flow rate needs to be increased. The opening of the second throttling device 17 is increased at each set interval E2. When the actual superheat is less than the set superheat ΔD2, it indicates that the heat dissipation load of the variable frequency drive module 15 is small and the refrigerant flow rate needs to be reduced. The opening of the second throttling device 17 is closed at each set time interval E2. When the set temperature △D2 < actual temperature < set temperature △C2, it indicates that the heat dissipation load of the variable frequency drive module 15 is moderate, and the current refrigerant flow rate is maintained, and the opening of the second throttling device 17 is maintained; Here, the set time E2 is less than the set time E1.

[0051] This design achieves a more timely superheat response through a shorter setting time. When the actual superheat deviates from the set value, the opening adjustment interval of the second throttling device 17 is shorter, which can quickly correct the heat dissipation load deviation and avoid overshoot or undershoot of the IPM temperature due to adjustment delay. It ensures that the IPM temperature returns to stability in a short time and is suitable for scenarios with fluctuating heat dissipation loads.

[0052] It should be understood that when it is necessary to reduce the opening of the second throttling device 17, if the opening of the second throttling device 17 has reached the minimum number of steps and the first throttling device 16 has not reached the minimum number of steps, the opening of the first throttling device 16 is reduced to reduce the amount of refrigerant and avoid the IPM temperature being too low.

[0053] like Figure 1 As shown, for ease of understanding, a detailed description is given by taking an application example of the present invention as an example.

[0054] Cooling mode / cooling and heating water mode When the ambient temperature is higher than the set inflection point temperature of 40°C in the cooling mode / cooling and heating water mode, the heat dissipation effect of the IPM becomes poor due to the high temperature of the high-pressure refrigerant. The first heat dissipation strategy is implemented, which is mainly regulated by the first throttling device 16: When the actual temperature of the IPM is greater than or equal to the set temperature B, the opening of the first throttling device 16 is increased by 10B every 10 seconds until the maximum opening is reached; When the actual temperature of the IPM is less than the set temperature B, the first throttling device 16 maintains the set initial opening, and adjusts the opening of the second throttling device 17 in a set slow manner to obtain the actual superheat of the heat dissipation pipeline. When the actual superheat is greater than 3°C, the opening of the second throttling device 17 is increased by 5B every 60 seconds until the maximum opening; when the actual superheat is between 1~3°C, the opening of the second throttling device 17 is maintained; when the actual superheat is less than 1°C, the opening of the second throttling device 17 is closed, and is closed by 5B every 60 seconds until the minimum number of steps is reached. If the superheat still cannot be met, the opening of the first throttling device 16 is closed, and is closed by 5B every 30 seconds.

[0055] When the ambient temperature is lower than the set inflection point temperature of 40°C in the cooling mode / cooling and heating water mode, the liquid refrigerant can better dissipate heat to the IPM, and the second heat dissipation strategy is implemented, which is mainly regulated by the second throttling device 17: When the actual temperature of the IPM is greater than or equal to the set temperature B1, the opening of the second throttling device 17 is increased by 10B every 30 seconds until the maximum opening. If the actual temperature still cannot meet the set temperature, the first throttling device 16 is opened and opened by 5B every 10 seconds. When the actual temperature of the IPM is less than or equal to the set temperature A1, the first throttling device 16 is closed, and the opening of the second throttling device 17 is adjusted in a set slow manner to obtain the actual superheat of the heat dissipation pipeline. When the actual superheat is greater than 3°C, the opening of the second throttling device 17 is increased by 5B every 60 seconds until the maximum opening; when the actual superheat is between 1°C and 3°C, the opening of the second throttling device 17 is maintained; when the actual superheat is less than 1°C, the opening of the second throttling device 17 is decreased by 5B every 60 seconds until the minimum number of steps is reached; When the actual temperature of the IPM is between the set temperature A1 and the set temperature B1, the first throttling device 16 maintains the current opening and adjusts the opening of the second throttling device 17 according to the set fast method. When the actual superheat is greater than 5°C, the opening of the second throttling device 17 is increased by 5B every 30 seconds until the maximum opening; when the actual superheat is between 3~5°C, the opening of the second throttling device 17 is maintained; when the actual superheat is less than 3°C, the opening of the second throttling device 17 is reduced by 5B every 30 seconds until the minimum number of steps.

[0056] Heating mode / hot water mode / heating water mode When the water temperature is higher than the set inflection point temperature of 40°C in the heating mode / hot water mode / heating water mode, the heat dissipation effect of the IPM becomes poor due to the high temperature of the high-pressure refrigerant. The first heat dissipation strategy is implemented, which is mainly regulated by the first throttling device 16: When the actual temperature of the IPM is greater than or equal to the set temperature B, the opening of the first throttling device 16 is increased by 10B every 10 seconds until the maximum opening is reached; When the actual temperature of the IPM is less than the set temperature B, the first throttling device 16 maintains the set initial opening, and adjusts the opening of the second throttling device 17 in a set slow manner to obtain the actual superheat of the heat dissipation pipeline. When the actual superheat is greater than 3°C, the opening of the second throttling device 17 is increased by 5B every 60 seconds until the maximum opening; when the actual superheat is between 1~3°C, the opening of the second throttling device 17 is maintained; when the actual superheat is less than 1°C, the opening of the second throttling device 17 is closed, and is closed by 5B every 60 seconds until the minimum number of steps is reached. If the superheat still cannot be met, the opening of the first throttling device 16 is closed, and is closed by 5B every 30 seconds.

[0057] When the water temperature is lower than the set inflection point temperature of heating mode / hot water mode / heating water mode - 40°C, the liquid refrigerant can better dissipate heat to the IPM, and the second heat dissipation strategy is implemented - mainly based on the adjustment of the second throttling device 17: When the actual temperature of the IPM is greater than or equal to the set temperature B1, the opening of the second throttling device 17 is increased by 10B every 30 seconds until the maximum opening. If the actual temperature still cannot meet the set temperature, the first throttling device 16 is opened and opened by 5B every 10 seconds. When the actual temperature of the IPM is less than or equal to the set temperature A1, the first throttling device 16 is closed, and the opening of the second throttling device 17 is adjusted in a set slow manner to obtain the actual superheat of the heat dissipation pipeline. When the actual superheat is greater than 3°C, the opening of the second throttling device 17 is increased by 5B every 60 seconds until the maximum opening; when the actual superheat is between 1°C and 3°C, the opening of the second throttling device 17 is maintained; when the actual superheat is less than 1°C, the opening of the second throttling device 17 is decreased by 5B every 60 seconds until the minimum number of steps is reached; When the actual temperature of the IPM is between the set temperature A1 and the set temperature B1, the first throttling device 16 maintains the current opening and adjusts the opening of the second throttling device 17 according to the set fast method. When the actual superheat is greater than 5°C, the opening of the second throttling device 17 is increased by 5B every 30 seconds until the maximum opening; when the actual superheat is between 3~5°C, the opening of the second throttling device 17 is maintained; when the actual superheat is less than 3°C, the opening of the second throttling device 17 is reduced by 5B every 30 seconds until the minimum number of steps.

[0058] It should be noted that the terms used above are only for describing specific embodiments and are not intended to constrain exemplary embodiments according to the present invention. When the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof. The order of execution of actions, steps, etc. in the devices and methods shown in the specification and the drawings can be implemented in any order as long as there is no special explicit limitation on the order and as long as the output of the previous processing is not used in the subsequent processing. Similar sequential terms used for the convenience of description do not mean that they must be implemented in such an order.

[0059] Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but, where appropriate, such techniques, methods, and apparatus should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as constraints. Therefore, other examples of the exemplary embodiments may have different values. It should be noted that similar reference numerals and letters represent similar items in the following figures, and therefore, once an item is defined in one figure, it does not need to be further discussed in subsequent figures.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to restrict the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. Variable frequency heat pump unit, including: A refrigerant circulation loop and a variable frequency drive module, wherein the refrigerant circulation loop is formed by connecting a compressor, a heat exchanger assembly, a liquid reservoir, and a gas-liquid separator, wherein the heat exchanger assembly includes three heat exchangers, and at least two of the heat exchangers participate in the refrigerant circulation of the refrigerant circulation loop; It is characterized in that the variable frequency drive module is equipped with a heat dissipation pipeline, the outlet end of the heat dissipation pipeline is connected to the suction side of the compressor, and the inlet end of the heat dissipation pipeline is connected to the liquid storage chamber of the liquid reservoir through a first branch and a second branch respectively, the first branch is provided with a cooling pipe section located inside the gas-liquid separator, and a first throttling device is installed on the outlet side of the cooling pipe section, and the second branch is located outside the gas-liquid separator and is equipped with a second throttling device; The openings of the first throttling device and the second throttling device are adjustable and work in coordination.

2. The variable frequency heat pump unit according to claim 1, characterized in that: The three heat exchangers are respectively a first heat exchanger, a second heat exchanger and a third heat exchanger, and the exhaust side of the compressor can be switchably connected to the first end of any one of the heat exchangers; The second end of the first heat exchanger is connected to the liquid reservoir through a first outlet pipe and a first inlet pipe respectively; The second end of the second heat exchanger is connected to the liquid reservoir through a second outlet pipe; The second end of the third heat exchanger is connected to the liquid reservoir through a third outlet pipe and a third inlet pipe respectively; Each outlet pipe is equipped with a control valve allowing the refrigerant to flow to the liquid storage tank, and each inlet pipe is equipped with a throttling device.

3. The variable frequency heat pump unit according to claim 2, characterized in that: The second end of the second heat exchanger is also connected to the liquid reservoir through a second inlet pipe.

4. The variable frequency heat pump unit according to claim 2, characterized in that: The first heat exchanger is an air conditioning water heat exchanger, the second heat exchanger is a hot water heat exchanger, the third heat exchanger is an outdoor heat exchanger, and the working mode of the variable frequency heat pump unit includes at least one of a cooling mode, a heating mode, a hot water mode, a cooling and heating water mode, and a heating and heating water mode.

5. The variable frequency heat pump unit according to any one of claims 1 to 4, characterized in that: The first throttling device and the second throttling device are both electronic expansion valves.

6. A heat dissipation control method, the heat dissipation control method being applied to the variable frequency heat pump unit according to any one of claims 1 to 5, characterized in that: The heat dissipation control method includes: Obtaining the operating mode of the variable frequency heat pump unit and the temperature of the heat exchange medium on the condensing side of the refrigerant circulation loop; Comparing the condensing side heat exchange medium temperature with the set inflection point temperature corresponding to the current working mode; If the temperature of the heat exchange medium on the condensing side is greater than the set inflection point temperature, the first heat dissipation strategy based on the regulation of the first throttling device is executed; If the temperature of the heat exchange medium on the condensing side is less than the set inflection point temperature, the second heat dissipation strategy based on the regulation of the second throttling device is executed.

7. The heat dissipation control method according to claim 6, characterized in that: The first heat dissipation strategy includes: Obtaining the actual temperature of the variable frequency drive module; When the actual temperature is greater than or equal to the set temperature B, the opening of the first throttling device is increased; When the actual temperature is less than the set temperature B, the first throttling device is controlled to maintain the set initial opening, and the opening of the second throttling device is adjusted in a set slow manner.

8. The heat dissipation control method according to claim 6, wherein: The second heat dissipation strategy includes: Obtaining the actual temperature of the variable frequency drive module; When the actual temperature is greater than or equal to the set temperature B1, the opening of the second throttling device is increased. If the second throttling device is opened to the maximum opening, the opening of the first throttling device is increased. When the actual temperature is less than or equal to the set temperature A1, the first throttling device is closed, and the opening of the second throttling device is adjusted in a set slow manner; When the set temperature A1 is less than the actual temperature and less than the set temperature B1, the first throttling device is controlled to maintain the current opening, and the opening of the second throttling device is adjusted in a set fast manner.

9. The heat dissipation control method according to claim 8, characterized in that: The slow speed setting method includes: Obtaining an actual superheat of the heat dissipation pipeline; When the actual superheat is greater than the set superheat △C1, the opening of the second throttling device is increased at each set time interval E1; When the actual superheat is less than the set superheat △D1, the opening of the second throttling device is reduced at each set time interval E1; When the set temperature ΔD1 < the actual temperature < the set temperature ΔC1, the opening of the second throttling device is maintained.

10. The heat dissipation control method according to claim 9, wherein: The quick setting method includes: Obtaining an actual superheat of the heat dissipation pipeline; When the actual superheat is greater than the set superheat △C2, the opening of the second throttling device is increased at each set time interval E2; When the actual superheat is less than the set superheat △D2, the opening of the second throttling device is reduced at each set time interval E2; When the set temperature △D2 < actual temperature < set temperature △C2, maintain the opening of the second throttling device; Here, the set time E2 is less than the set time E1.

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