A method of controlling an electrically powered construction machine cooling system and a cooling system

Abstract

The application discloses a kind of electric engineering machinery cooling system control method and cooling system, system includes electric drive heat dissipation system, integrated air conditioning system and battery cooling system;Method includes: obtaining the monitoring data of cooling system, according to the monitoring data judges cab refrigeration demand degree and battery pack BMS cooling request mode;According to cab refrigeration demand degree and battery pack BMS cooling request mode, execute corresponding refrigeration instruction;When cab refrigeration demand degree or battery pack BMS cooling request mode changes, end operation.Obtain the monitoring data of cooling system, accurately determine cab refrigeration demand degree and battery pack BMS cooling request mode, adopt the mode of double electronic fan independent control to realize condenser and radiator accurate heat dissipation, adaptive adjustment compressor speed and electronic fan speed, to effectively realize the reasonable cold distribution of cab and battery pack by low energy consumption, guarantee ride comfort and safety.

Description

Technical Field

[0001] This invention relates to the field of pure electric excavator control technology, and specifically to a control method and cooling system for an electric construction machinery cooling system. Background Technology

[0002] Due to space constraints and the cooling requirements of the battery system, small and micro pure electric excavators need to integrate the air conditioning evaporator and battery cooler in parallel within the air conditioning system, sharing a single compressor. The air conditioning evaporator is used to cool the cab, while the battery cooler is used to cool the power battery. When the air conditioning system has sufficient cooling capacity, quickly and accurately achieving a balanced distribution of air conditioning cooling and battery cooling can effectively extend battery life and improve system stability.

[0003] In existing technical solutions, a dual electronic expansion valve mode is usually adopted. The opening degree control of the electronic expansion valve on the air conditioning side and the electronic expansion valve on the battery side is calculated to achieve bidirectional cooling capacity distribution. This solution increases the system cost to a certain extent, the control logic is more complex, and it is difficult to calibrate.

[0004] Another approach is to combine an electronic expansion valve with a battery cooler and use a variable-speed water pump to adjust the coolant flow rate to achieve cooling capacity compensation. This approach requires repeatedly starting and stopping the compressor, which not only significantly increases energy consumption but also affects driving comfort. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a control method and cooling system for the cooling system of electric engineering machinery, which can effectively realize the reasonable distribution of cooling capacity between the cab and the battery pack, and ensure driving comfort and safety.

[0006] To achieve the above objectives, the present invention is implemented using the following technical solution:

[0007] In a first aspect, the present invention provides a control method for a cooling system of electric engineering machinery, comprising the following steps:

[0008] Acquire monitoring data of the cooling system, and determine the cab cooling demand and battery pack BMS cooling request mode based on the monitoring data;

[0009] Execute the corresponding cooling command based on the cab's cooling demand and the battery pack BMS cooling request mode;

[0010] The operation ends when the cab cooling demand or the battery pack BMS cooling request mode changes.

[0011] Furthermore, acquiring monitoring data from the cooling system, and determining the cab cooling demand and battery pack BMS cooling request mode based on the monitoring data, including:

[0012] If there is no cooling requirement in the cab, and only the battery pack requires cooling, then determine the current cooling request status of the BMS:

[0013] Obtain the highest temperature Tmax and the average temperature Tmean of the battery pack cells;

[0014] When the highest temperature of the battery pack cells, Tmax, is greater than or equal to the upper limit of the cooling threshold, Ttop, and the average temperature of the battery pack cells, Tmean, is greater than or equal to the upper limit of the cooling threshold, Tpoi, the battery management system (BMS) will request the fast cooling mode.

[0015] Furthermore, the method is based on a cooling system, which includes at least an electric drive cooling system, an integrated air conditioning system, and a battery cooling system;

[0016] The electric drive cooling system includes an electric drive radiator; the fan of the electric drive radiator adopts a dual-fan configuration, including fan one and fan two, and forms independent zone temperature control with the condenser of the integrated air conditioning system and the battery radiator of the battery cooling system, respectively; the coolant is cooled by air through the electric drive radiator, wherein the electric drive radiator is independently temperature-controlled by the dual electric fans, forming an electric drive cooling circulation loop:

[0017] The integrated air conditioning system includes a compressor, a condenser, an electronic expansion valve, a pressure sensor P1, and a temperature sensor installed on the evaporator.

[0018] The battery cooling system includes a variable frequency water pump, a battery cooler, and temperature sensors installed at the inlet and outlet of the battery pack; the integrated air conditioning system and the battery cooling system achieve heat exchange through the battery cooler;

[0019] Based on the cab's cooling demand and the battery pack BMS cooling request mode, execute the corresponding cooling commands, including:

[0020] When only the Battery Management System (BMS) requests the fast cooling mode, start the compressor and fan 1, and adjust the variable frequency water pump 1 to 50% speed;

[0021] Initialize the opening of the electronic expansion valve, comprehensively calculate the feedback values ​​T1 and T2 of the battery pack inlet and outlet coolant temperature, and dynamically adjust the opening of the electronic expansion valve at a rate of N1 steps / s. The dynamic adjustment of the expansion valve opening is based on the target superheat of the battery cooler, and the adjustment terminates when the highest energy efficiency ratio is reached.

[0022] The refrigerant circuit pressure value fed back by pressure sensor P1 is monitored in real time, and the optimal speed of compressor and condenser fan is matched according to the refrigerant circuit pressure value until the temperature difference between T1 and T2 tends to stabilize or the BMS cooling request mode changes.

[0023] Furthermore, acquiring monitoring data from the cooling system, and determining the cab cooling demand and battery pack BMS cooling request mode based on the monitoring data, including:

[0024] If there is no cooling requirement in the cab, and only the battery pack requires cooling, then determine the current cooling request status of the BMS:

[0025] Obtain the highest temperature Tmax and the average temperature Tmean of the battery pack cells;

[0026] When the highest temperature of the battery pack cells, Tmax, is greater than or equal to the lower limit of the cooling threshold, Tdow, and the average temperature of the battery pack cells, Tmean, is greater than or equal to the lower limit of the cooling threshold, Tpow, the Battery Management System (BMS) will request a slow cooling mode.

[0027] Furthermore, the battery cooling system also includes a solenoid valve and a battery radiator; after passing through the variable frequency water pump, the coolant is divided into two branches by the solenoid valve: the first branch passes through the battery radiator and the battery cooler, is reversed by the solenoid valve, and then flows through the battery pack to cool it; the second branch passes through the solenoid valve and the battery cooler, flows through the battery pack to cool it, and the coolant is in a self-circulating state.

[0028] Based on the cab's cooling demand and the battery pack BMS cooling request mode, execute the corresponding cooling commands, including:

[0029] The compressor is turned off when only the Battery Management System (BMS) requests slow cooling mode;

[0030] Adjust the fan speed of fan one and fan two according to the temperature of the electric drive radiator;

[0031] Turn on the variable frequency water pump and adjust it to 50% speed;

[0032] Adjust the solenoid valve to switch the battery cooling circuit to the first branch. The coolant passes through the battery radiator, exchanges heat through the second fan, and then passes through the battery pack for cooling.

[0033] The battery pack inlet and outlet coolant temperature feedback values ​​T1 and T2 are calculated comprehensively. Based on these values, the fan speed is adjusted until the temperature difference between T1 and T2 stabilizes or the BMS cooling request mode changes.

[0034] Furthermore, acquiring monitoring data from the cooling system, and determining the cab cooling demand and battery pack BMS cooling request mode based on the monitoring data, including:

[0035] If both cab cooling and battery pack cooling are required, determine the cab cooling demand status and the current cooling request mode of the BMS:

[0036] Acquire the cabin temperature setpoint Tcin, evaporator blower speed Sed, maximum battery pack cell temperature Tmax, and average battery pack cell temperature Tmean;

[0037] When the cabin temperature setpoint Tcin ≤ temperature limit Tdin, and the evaporator blower setting Sed ≥ calibrated setting Sbe, the highest battery pack cell temperature Tmax ≥ cooling threshold limit Ttop, and the average battery pack cell temperature Tmean ≥ cooling threshold limit equilibrium point Tpoi, the cabin cooling is in a state of high demand, and the battery management system (BMS) will request fast cooling mode.

[0038] Furthermore, based on the cab's cooling demand and the battery pack BMS cooling request mode, corresponding cooling commands are executed, including:

[0039] When the cab cooling is in high demand, the Battery Management System (BMS) requests the fast cooling mode.

[0040] Turn on the compressor and fan one, initialize the opening of the electronic expansion valve, and adjust the variable frequency water pump one to 80% speed.

[0041] The battery cooling circuit is switched to the first branch via a solenoid valve. The battery cooler then flows through the battery radiator and battery cooler, and finally through the battery pack microchannels for cooling.

[0042] By comprehensively calculating the battery pack inlet and outlet coolant temperature feedback values ​​T1 and T2, the fan speed is increased to the maximum within the allowable value to achieve maximum heat exchange.

[0043] Based on the system refrigerant pressure and evaporator surface temperature fed back by pressure sensor P1 and temperature sensor T3, the compressor and fan speeds are matched.

[0044] The electronic expansion valve is gradually opened from its initial position at N2 steps / s to achieve optimal heat exchange, until the temperature difference between T1 and T2 stabilizes or the BMS cooling request mode changes. Optimal heat exchange is the optimal solution for heat dissipation based on the current state and the target energy efficiency ratio.

[0045] Furthermore, acquiring monitoring data from the cooling system, and determining the cab cooling demand and battery pack BMS cooling request mode based on the monitoring data, including:

[0046] If both cab cooling and battery pack cooling are required, determine the cab cooling demand status and the current cooling request mode of the BMS:

[0047] Acquire the cabin temperature setpoint Tcin, evaporator blower speed Sed, maximum battery pack cell temperature Tmax, and average battery pack cell temperature Tmean;

[0048] When the cabin temperature setpoint Tcin ≤ temperature limit Tdin, the evaporator blower setting Sed ≥ calibration setting Sbe, the highest cell temperature Tmax ≥ lower limit of cooling threshold Tdow, and the average cell temperature Tmean ≥ lower limit of cooling threshold equilibrium point Tpow, the cabin cooling is in a state of high demand, and the battery management system (BMS) will request slow cooling mode.

[0049] Furthermore, based on the cab's cooling demand and the battery pack BMS cooling request mode, corresponding cooling commands are executed, including:

[0050] When the cab cooling is in high demand and the Battery Management System (BMS) requests slow cooling mode, the compressor is turned on and the electronic expansion valve is turned off.

[0051] Based on the system refrigerant pressure and evaporator surface temperature fed back by pressure sensor P1 and temperature sensor T3, adjust the fan speed to the corresponding speed.

[0052] Turn on the variable frequency water pump and adjust it to 50% speed.

[0053] The circuit will switch to the first branch via a solenoid valve. The coolant will pass through the battery radiator, exchange heat with the second fan, and then be cooled by the battery pack.

[0054] The battery pack inlet and outlet coolant temperature feedback values ​​T1 and T2 will be calculated comprehensively, and the fan speed will be dynamically adjusted until the temperature difference between T1 and T2 tends to stabilize or the BMS cooling request mode changes.

[0055] Furthermore, acquiring monitoring data from the cooling system, and determining the cab cooling demand and battery pack BMS cooling request mode based on the monitoring data, including:

[0056] If both cab cooling and battery pack cooling are required, determine the cab cooling demand status and the current cooling request mode of the BMS:

[0057] Acquire the cabin temperature setpoint Tcin, evaporator blower speed Sed, maximum battery pack cell temperature Tmax, and average battery pack cell temperature Tmean;

[0058] When the cabin temperature setpoint Tcin is greater than or equal to the temperature limit Tdin, and the evaporator blower setting Sed is less than or equal to the calibrated setting Sbe, the highest battery pack cell temperature Tmax is greater than or equal to the upper limit of the cooling threshold Ttop, and the average battery pack cell temperature Tmean is greater than or equal to the upper limit of the cooling threshold equilibrium point Tpoi, the cabin cooling is in a weak demand state, and the battery management system (BMS) will request the fast cooling mode.

[0059] Furthermore, based on the cab's cooling demand and the battery pack BMS cooling request mode, corresponding cooling commands are executed, including:

[0060] When the cab cooling is in a low-demand state, the Battery Management System (BMS) will request the fast cooling mode. It will then calculate the battery pack inlet and outlet coolant temperature feedback values ​​T1 and T2, and increase the water pump speed to achieve the maximum flow rate.

[0061] Based on the system refrigerant pressure and evaporator surface temperature fed back by pressure sensor P1 and temperature sensor T3, the compressor and condenser fan speeds are matched.

[0062] The electronic expansion valve opening is initialized and gradually increased at N3 steps / s until the optimal heat exchange is achieved, the temperature difference between T1 and T2 stabilizes, or the BMS cooling request mode changes. The optimal heat exchange is determined based on the current state and the target energy efficiency ratio, yielding the best solution for the heat dissipation state.

[0063] Furthermore, the method for comprehensively calculating the battery pack inlet and outlet coolant temperature feedback values ​​T1 and T2 includes: adding 2 degrees to the inlet and outlet temperature monitoring values ​​collected by the sensor as the battery pack inlet and outlet coolant temperature feedback values ​​T1 and T2.

[0064] Furthermore, acquiring monitoring data from the cooling system, and determining the cab cooling demand and battery pack BMS cooling request mode based on the monitoring data, including:

[0065] If both cab cooling and battery pack cooling are required, determine the cab cooling demand status and the current cooling request mode of the BMS:

[0066] Acquire the cabin temperature setpoint Tcin, evaporator blower speed Sed, maximum battery pack cell temperature Tmax, and average battery pack cell temperature Tmean;

[0067] When the cabin temperature setpoint Tcin is greater than or equal to the temperature limit Tdin, and the evaporator blower setting Sed is less than or equal to the calibrated setting Sbe, the highest cell temperature Tmax is greater than or equal to the lower limit of the cooling threshold Tdow, and the average cell temperature Tmean is greater than or equal to the lower limit of the cooling threshold equilibrium point Tpow, the cabin cooling is in a weak demand state, and the battery management system (BMS) will request a slow cooling mode.

[0068] Furthermore, based on the cab's cooling demand and the battery pack BMS cooling request mode, corresponding cooling commands are executed, including:

[0069] When the cab cooling demand is low, the Battery Management System (BMS) will request slow cooling mode and activate the compressor.

[0070] Adjust the fan speed according to the monitored temperature of the electric drive radiator.

[0071] Turn on the variable frequency water pump and adjust it to 50% speed.

[0072] Adjust the solenoid valve to switch the battery cooling circuit to the first branch, so that the coolant passes through the battery radiator, exchanges heat through the second fan, and then cools the battery pack.

[0073] Furthermore, the method also includes:

[0074] When the battery pack is not started, the variable frequency water pump is controlled at its initial speed and switched to the second branch through the solenoid valve, so that the coolant is in a self-circulating state.

[0075] In a second aspect, the present invention provides a cooling system for electric engineering machinery, comprising:

[0076] The monitoring system is used to acquire monitoring data of the cooling system;

[0077] A controller is configured to execute the control method as described in the first aspect based on the monitoring data.

[0078] Compared with the prior art, the beneficial effects achieved by the present invention are as follows:

[0079] (1) The present invention acquires monitoring data of the cooling system, determines the cooling demand of the cab and the cooling request mode of the battery pack BMS based on the monitoring data, and executes corresponding operation instructions based on the cooling demand of the cab and the cooling request mode of the battery pack BMS. The control process is clear and reliable, and can effectively achieve reasonable cooling distribution between the cab and the battery pack with low energy consumption, ensuring driving comfort and safety.

[0080] (2) The condenser and battery radiator of the present invention are arranged side by side on the windward side of the electric drive radiator. The dual electronic fan independent control mode is adopted to realize the precise heat dissipation of the condenser and radiator. The compressor speed and the electronic fan speed are adaptively adjusted, thereby achieving a reasonable distribution of cooling capacity between the cab and the battery pack with low energy consumption, ensuring driving comfort and safety.

[0081] (3) The present invention obtains monitoring data of the cooling system, accurately judges the cooling demand of the cab and the cooling request mode of the battery pack BMS, and realizes the secondary cooling of the battery pack by connecting the variable frequency water pump, the battery radiator and the battery cooler in series. At the same time, the opening of the electronic expansion valve and the speed of the variable frequency water pump are dynamically compensated and adjusted, which can effectively prevent sudden temperature changes inside the cab and ensure safety and driving comfort. Attached Figure Description

[0082] Figure 1 This is a schematic diagram of the overall thermal management system;

[0083] Figure 2 This is a flowchart of the overall thermal management control system.

[0084] Figure 3 A flowchart of the cooling process for a single battery pack;

[0085] Figure 4 A flowchart illustrating the cooling process for both the cab and the battery pack.

[0086] Figure 5 A block diagram for dynamic optimization and collaborative control strategies. Detailed Implementation

[0087] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0088] Example 1:

[0089] This embodiment provides a control method for a cooling system of electric construction machinery. Based on the cooling system, a schematic diagram of the overall thermal management system and the control system flow are shown below. Figure 1 , 2 As shown in 3 and 4:

[0090] First, it is necessary to obtain the cooling demand of the cab and the cooling request issued by the battery management system (BMS). The air conditioning system pressure, battery pack cell temperature, and battery and electric drive radiator temperature are monitored in real time through the whole machine control module. The internal temperature of the cab and the external ambient temperature are compared to accurately control the compressor, electric fan speed, electronic expansion valve opening and electric water pump flow.

[0091] Cooling system, including: Figure 1 As shown, the thermal management system of small electric construction machinery mainly includes an electric drive cooling system, an integrated air conditioning system, and a battery cooling system. The electric drive cooling system shares a condenser fan with the integrated air conditioning system and the battery cooling system. The condenser of the air conditioning system and the battery radiator of the battery cooling system are arranged side by side on the windward side of the electric drive radiator. At the same time, the two subsystems exchange heat through the battery cooler.

[0092] Electric drive cooling circulation loop: The coolant flows through the OBC, motor, and motor controller after being pumped by the water pump, and then is cooled by the electric drive radiator. The electric drive radiator is independently temperature controlled by dual electric fans, and finally forms a cooling loop. An expansion tank and temperature sensor are installed in the middle of the loop.

[0093] The refrigerant circulation loop of the integrated air conditioning system: the refrigerant after passing through the compressor and condenser is divided into two branches. One branch passes through the thermal expansion valve and evaporator to cool the cab, and the other branch passes through the electronic expansion valve and heat exchanger to exchange heat with the battery pack. The condenser and the electric drive radiator share an electric fan. Pressure sensors and temperature sensors are installed in the entire circulation loop.

[0094] Battery cooling circuit: After passing through the variable frequency water pump, the coolant is divided into two branches by a three-way solenoid valve: one branch passes through the battery radiator and battery cooler, is switched by two three-way solenoid valves, and then flows through the battery pack to cool it; the other branch passes through the three-way solenoid valve and battery cooler, and then flows through the battery pack to cool it. An expansion tank and temperature sensor are installed in the middle of the circuit.

[0095] The condenser and battery radiator of this system are arranged side by side on the windward side of the electric drive radiator; the electric drive radiator of this system adopts a dual electronic fan form, and forms an independent zone temperature control mode for the condenser and battery radiator respectively.

[0096] Specifically, acquiring monitoring data from the cooling system, and determining the cab's cooling demand and the battery pack BMS cooling request mode based on the monitoring data, including:

[0097] The cooling request mode of the battery management system (BMS) is as follows: First, based on the overall operating status, the signal feedback status of the BMS is monitored in real time, including the highest temperature, lowest temperature, and average temperature of the battery cells. This allows for accurate determination of the battery cooling threshold, obtaining the target cooling water temperature and the cooling enable request flag information, and then entering the cooling request state.

[0098] Figure 5For the collaborative control part of the dynamic optimization cooling system, precise adjustment of speed, temperature, pressure, and flow rate is achieved by mutual compensation of fuzzy control and PID control. Based on experimental results, the system superheat and COP value (coefficient of performance) corresponding to the opening of the electronic expansion valve at different compressor speeds are pre-calibrated and fitted. Taking into account the system superheat and COP value, the initial opening and target superheat of the electronic expansion valve are optimized. At the same time, the compressor speed is used as the reference quantity for the opening control strategy. On this basis, the target superheat and target power initial values ​​are introduced. Finally, a control strategy is established that correlates the compressor speed, cooling fan speed, variable frequency water pump flow rate, and battery cooler superheat as the adjustment target, so as to achieve the optimal solution of heat dissipation state with the lowest energy consumption.

[0099] Specifically, if there is no cooling requirement in the cab and only the battery pack requires cooling, the system determines whether the current cooling request of the BMS is in fast cooling mode: when the highest temperature of the battery pack cells Tmax is greater than or equal to the upper limit of the cooling threshold Ttop, and the average temperature of the battery pack cells Tmean is greater than or equal to the upper limit of the cooling threshold equilibrium point Tpoi, the battery management system (BMS) will request fast cooling mode. According to the execution priority of the control system, the compressor and fan 1 will be started first, the variable frequency water pump 1 will be adjusted to 50% speed, the opening of the electronic expansion valve will be initialized, the feedback values ​​of the battery pack inlet and outlet coolant temperature T1 and T2 will be calculated comprehensively, the opening of the expansion valve will be dynamically adjusted at a rate of N1 steps / s, and the refrigerant circuit pressure value P1 will be monitored in real time. At the same time, the optimal speed of the compressor and condenser fan will be matched.

[0100] The battery pack inlet and outlet coolant temperature feedback values ​​T1 and T2 are calculated comprehensively, instead of directly using the values ​​detected by temperature sensors. This is because the initial temperature value obtained through temperature sensor monitoring needs to be compensated for by the controller to compensate for errors and for safety reasons. Specifically, the method for comprehensively calculating the battery pack inlet and outlet coolant temperature feedback values ​​T1 and T2 includes: adding 2 degrees to the inlet and outlet temperature monitoring values ​​collected by the sensors to compensate for errors, comparing with the temperature standard value, and delaying the cooling process to ensure that the battery temperature reaches a safe value.

[0101] When the highest cell temperature Tmax of the battery pack is greater than or equal to the lower limit of the cooling threshold Tdow, and the average cell temperature Tmean is greater than or equal to the lower limit of the cooling threshold equilibrium point Tpow, the Battery Management System (BMS) will request a slow cooling mode. According to the execution priority of the control system, the compressor is shut down first, and the first fan is adjusted to the corresponding speed according to the temperature monitored by the electric drive radiator. The variable frequency water pump is turned on and adjusted to 50% speed. Solenoid valves 1 and 2 are opened and 3 is closed. The coolant passes through the battery radiator, exchanges heat through the second fan, and then passes through the battery pack for cooling. The feedback values ​​of the coolant temperature at the inlet and outlet of the battery pack T1 and T2 are calculated comprehensively, and the speed of the second fan is dynamically adjusted. When the temperature difference between T1 and T2 tends to stabilize, the cooling request mode of the BMS disappears.

[0102] (2) If there is a demand for both cab cooling and battery pack cooling, the demand status of cab cooling and the current cooling request mode of BMS are determined: when the cab temperature setpoint Tcin ≤ temperature limit Tdin, and the evaporator blower speed Sed ≥ calibration speed Sbe, the highest battery pack cell temperature Tmax ≥ cooling threshold upper limit Ttop, and the average battery pack cell temperature Tmean ≥ cooling threshold upper limit equilibrium point Tpoi, the cab cooling is in a strong demand state, and the battery management system BMS will request fast cooling mode.

[0103] First, the compressor and fan one are turned on, the electronic expansion valve opening is initialized, and the variable frequency water pump one is adjusted to 80% speed. Coolant flows through solenoid valves 1 and 2, passes through the battery radiator and battery cooler, and then flows through the battery pack microchannels for cooling. Based on the execution priority of the control system, the feedback values ​​T1 and T2 of the coolant temperature at the battery pack inlet and outlet are calculated comprehensively. The speed of fan two is prioritized to achieve maximum heat exchange. Based on the system refrigerant pressure and evaporator surface temperature feedback from pressure sensor P1 and temperature sensor T3, the speeds of the compressor and fan one are matched. The electronic expansion valve opening gradually increases from its initial position at N2 steps / s to achieve optimal heat exchange. Optimal heat exchange is the optimal solution for heat dissipation obtained by the system based on the current state and the target energy efficiency ratio.

[0104] When the battery pack does not require cooling, the water pump is at its initial speed, solenoid valves 1 and 3 are open (switching to the second branch via the solenoid valve), and the coolant is in self-circulation mode. Note: At this time, the battery pack does not dissipate heat and is always in a cooling activation state.

[0105] ② When the setpoint Tcin in the cab is less than or equal to the temperature limit Tdin, and the evaporator blower setting Sed is greater than or equal to the calibrated setting Sbe, the highest cell temperature Tmax is greater than or equal to the lower limit of the cooling threshold Tdow, and the average cell temperature Tmean is greater than or equal to the lower limit of the cooling threshold equilibrium point Tpow, the cab cooling is in a state of high demand, and the battery management system (BMS) will request the slow cooling mode.

[0106] According to the execution priority of the control system, the compressor is first turned on, the electronic expansion valve is turned off, and the first fan is adjusted to the corresponding speed according to the data feedback of P1 and T3. The variable frequency water pump is turned on and adjusted to 50% speed. Solenoid valves 1 and 2 are opened and 3 is closed. The coolant passes through the battery radiator, exchanges heat through the second fan, and then passes through the battery pack for cooling. The feedback values ​​of the coolant temperature at the inlet and outlet of the battery pack, T1 and T2, are calculated comprehensively, and the speed of the second fan is dynamically adjusted. The temperature difference between the inlet and outlet of the battery pack, T1 and T2, is calculated comprehensively. When the temperature difference between T1 and T2 tends to stabilize, the cooling request mode of the BMS disappears, and the cooling capacity requirement of the cab is maintained.

[0107] ③ When the cab temperature setpoint Tcin ≥ temperature limit Tdin, and the evaporator blower speed Sed ≤ calibrated speed Sbe, and the battery pack cell maximum temperature Tmax ≥ cooling threshold upper limit Ttop, while the battery pack cell average temperature Tmean ≥ cooling threshold upper limit equilibrium point Tpoi, the cab cooling is in a low-demand state, and the Battery Management System (BMS) will request fast cooling mode. Based on the control system's execution priority, the system comprehensively calculates the battery pack inlet and outlet coolant temperature feedback values ​​T1 and T2, prioritizing increasing the water pump speed to achieve maximum flow. Based on the system refrigerant pressure and evaporator surface temperature feedback from pressure sensor P1 and temperature sensor T3, the compressor and condenser fan speeds are matched, and the electronic expansion valve opening is initialized, gradually opening at N3 steps / s to achieve optimal heat exchange.

[0108] ④ When the setpoint temperature Tcin in the cab is greater than or equal to the temperature limit Tdin, and the evaporator blower speed Sed is less than or equal to the calibrated speed Sbe, and the highest cell temperature Tmax is greater than or equal to the lower limit of the cooling threshold Tdow, and the average cell temperature Tmean is greater than or equal to the lower limit of the cooling threshold equilibrium point Tpow, the cab cooling is in a weak demand state, and the Battery Management System (BMS) will request a slow cooling mode. According to the execution priority of the control system, the compressor is first turned on, and the electric fan one is adjusted to the corresponding speed according to the temperature monitored by the electric drive radiator. The variable frequency water pump one is turned on and adjusted to 50% speed. Solenoid valves 1 and 2 are opened and 3 is closed. The coolant passes through the battery radiator, exchanges heat through the electric fan two, and then passes through the battery pack for cooling. The feedback values ​​of the coolant temperature at the inlet and outlet of the battery pack T1 and T2 are calculated comprehensively, and the speed of the electric fan two is dynamically adjusted. When the temperature difference between T1 and T2 tends to stabilize, the BMS cooling request mode disappears.

[0109] Example 2:

[0110] This embodiment provides a cooling system for electric construction machinery, including: Figure 1 As shown, the thermal management system of small electric construction machinery mainly includes an electric drive cooling system, an integrated air conditioning system, and a battery cooling system. The electric drive cooling system shares a condenser fan with the integrated air conditioning system and the battery cooling system. The condenser of the air conditioning system and the battery radiator of the battery cooling system are arranged side by side on the windward side of the electric drive radiator. At the same time, the two subsystems exchange heat through the battery cooler.

[0111] Electric drive cooling circulation loop: The coolant flows through the OBC, motor, and motor controller after being pumped by the water pump, and then is cooled by the electric drive radiator. The electric drive radiator is independently temperature controlled by dual electric fans, and finally forms a cooling loop. An expansion tank and temperature sensor are installed in the middle of the loop.

[0112] The refrigerant circulation loop of the integrated air conditioning system: the refrigerant after passing through the compressor and condenser is divided into two branches. One branch passes through the thermal expansion valve and evaporator to cool the cab, and the other branch passes through the electronic expansion valve and heat exchanger to exchange heat with the battery pack. The condenser and the electric drive radiator share an electric fan. Pressure sensors and temperature sensors are installed in the entire circulation loop.

[0113] Battery cooling circuit: After passing through the variable frequency water pump, the coolant is divided into two branches by a three-way solenoid valve: one branch passes through the battery radiator and battery cooler, is switched by two three-way solenoid valves, and then flows through the battery pack to cool it; the other branch passes through the three-way solenoid valve and battery cooler, and then flows through the battery pack to cool it. An expansion tank and temperature sensor are installed in the middle of the circuit.

[0114] The condenser and battery radiator of this system are arranged side by side on the windward side of the electric drive radiator.

[0115] The electric drive radiator fan of this system adopts a dual electronic fan form, and forms an independent zone temperature control mode for the condenser and battery radiator respectively.

[0116] This system uses a series connection of a variable frequency water pump, a battery radiator, and a battery cooler to achieve flow compensation under different flow resistances, as well as pre-cooling of the battery radiator plus in-depth cooling of the battery cooler, i.e., "two-stage cooling," to compensate and adjust the opening of the electronic expansion valve.

[0117] This cooling system is equipped with a controller and a monitoring system. The monitoring system is used to acquire monitoring data in the cooling system, such as the setpoint temperature Tcin in the driver's cab, the evaporator blower speed Sed, the maximum temperature of the battery pack cells Tmax, and the average temperature of the battery pack cells Tmean. The controller is used to execute the control method as described in Example 1.

[0118] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0119] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0120] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0121] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0122] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A control method for a cooling system of electric engineering machinery, characterized in that, Includes the following steps: Acquire monitoring data of the cooling system, and determine the cab cooling demand and battery pack BMS cooling request mode based on the monitoring data; Execute the corresponding cooling command based on the cab's cooling demand and the battery pack BMS cooling request mode; The operation ends when the cab cooling demand or the battery pack BMS cooling request mode changes. Acquire monitoring data from the cooling system, and determine the cab cooling demand and battery pack BMS cooling request mode based on the monitoring data, including: If there is no cooling requirement in the cab, and only the battery pack requires cooling, then determine the current cooling request status of the BMS: Obtain the highest temperature Tmax and the average temperature Tmean of the battery pack cells; When the highest temperature of the battery pack cells Tmax is greater than or equal to the upper limit of the cooling threshold Ttop, and the average temperature of the battery pack cells Tmean is greater than or equal to the upper limit of the cooling threshold equilibrium point Tpoi, the battery management system (BMS) requests the fast cooling mode. The method is based on a cooling system, which includes at least an electric drive heat dissipation system, an integrated air conditioning system, and a battery cooling system. The electric drive cooling system includes an electric drive radiator; the fan of the electric drive radiator adopts a dual-fan configuration, including fan one and fan two, and forms independent zone temperature control with the condenser of the integrated air conditioning system and the battery radiator of the battery cooling system, respectively; the coolant is cooled by air through the electric drive radiator, wherein the electric drive radiator is independently temperature-controlled by the dual electric fans, forming an electric drive cooling circulation loop: The integrated air conditioning system includes a compressor, a condenser, an electronic expansion valve, a pressure sensor P1, and a temperature sensor installed on the evaporator. The battery cooling system includes a variable frequency water pump, a battery cooler, and temperature sensors installed at the inlet and outlet of the battery pack; the integrated air conditioning system and the battery cooling system achieve heat exchange through the battery cooler; Based on the cab's cooling demand and the battery pack BMS cooling request mode, execute the corresponding cooling commands, including: When only the Battery Management System (BMS) requests the fast cooling mode, start the compressor and fan 1, and adjust the variable frequency water pump 1 to 50% speed; Initialize the opening of the electronic expansion valve, comprehensively calculate the feedback values ​​T1 and T2 of the battery pack inlet and outlet coolant temperature, and dynamically adjust the opening of the electronic expansion valve at a rate of N1 steps / s. The dynamic adjustment of the expansion valve opening is based on the target superheat of the battery cooler, and the adjustment terminates when the highest energy efficiency ratio is reached. The refrigerant circuit pressure value fed back by pressure sensor P1 is monitored in real time, and the optimal speed of compressor and condenser fan is matched according to the refrigerant circuit pressure value until the temperature difference between T1 and T2 tends to stabilize or the BMS cooling request mode changes. Acquire monitoring data from the cooling system, and determine the cab cooling demand and battery pack BMS cooling request mode based on the monitoring data, including: If there is no cooling requirement in the cab, and only the battery pack requires cooling, then determine the current cooling request status of the BMS: Obtain the highest temperature Tmax and the average temperature Tmean of the battery pack cells; When the highest temperature of the battery pack cells, Tmax, is greater than or equal to the lower limit of the cooling threshold, Tdow, and the average temperature of the battery pack cells, Tmean, is greater than or equal to the lower limit of the cooling threshold, Tpow, the Battery Management System (BMS) requests a slow cooling mode.

2. The control method for the cooling system of electric engineering machinery according to claim 1, characterized in that, The battery cooling system also includes a solenoid valve and a battery radiator; after passing through the variable frequency water pump, the coolant is divided into two branches by the solenoid valve: the first branch passes through the battery radiator and the battery cooler, is reversed by the solenoid valve, and then flows through the battery pack to cool it; the second branch passes through the solenoid valve and the battery cooler, flows through the battery pack to cool it, and the coolant is in a self-circulating state. Based on the cab's cooling demand and the battery pack BMS cooling request mode, execute the corresponding cooling commands, including: The compressor is turned off when only the Battery Management System (BMS) requests slow cooling mode; Adjust the speed of fan one and fan two according to the temperature of the electric drive radiator; Turn on the variable frequency water pump and adjust it to 50% speed; Adjust the solenoid valve to switch the battery cooling circuit to the first branch. The coolant passes through the battery radiator, exchanges heat through the second fan, and then passes through the battery pack for cooling. The battery pack inlet and outlet coolant temperature feedback values ​​T1 and T2 are calculated comprehensively. Based on these values, the fan speed is adjusted until the temperature difference between T1 and T2 stabilizes or the BMS cooling request mode changes.

3. The control method for the cooling system of electric engineering machinery according to claim 2, characterized in that, Acquire monitoring data from the cooling system, and determine the cab cooling demand and battery pack BMS cooling request mode based on the monitoring data, including: If both cab cooling and battery pack cooling are required, determine the cab cooling demand status and the current cooling request mode of the BMS: Acquire the cabin temperature setpoint Tcin, evaporator blower speed Sed, maximum battery pack cell temperature Tmax, and average battery pack cell temperature Tmean; When the cabin temperature setpoint Tcin ≤ temperature limit Tdin, and the evaporator blower setting Sed ≥ calibrated setting Sbe, the highest battery pack cell temperature Tmax ≥ cooling threshold limit Ttop, and the average battery pack cell temperature Tmean ≥ cooling threshold limit equilibrium point Tpoi, the cabin cooling is in a state of high demand, and the battery management system (BMS) will request fast cooling mode.

4. The control method for the cooling system of electric engineering machinery according to claim 3, characterized in that, Based on the cab's cooling demand and the battery pack BMS cooling request mode, execute the corresponding cooling commands, including: When the cab cooling is in high demand, the Battery Management System (BMS) requests the fast cooling mode. Turn on the compressor and fan one, initialize the opening of the electronic expansion valve, and adjust the variable frequency water pump one to 80% speed. The battery cooling circuit is switched to the first branch via a solenoid valve. The battery cooler then flows through the battery radiator and battery cooler, and finally through the battery pack microchannels for cooling. By comprehensively calculating the battery pack inlet and outlet coolant temperature feedback values ​​T1 and T2, the fan speed is increased to the maximum within the allowable value to achieve maximum heat exchange. Based on the system refrigerant pressure and evaporator surface temperature fed back by pressure sensor P1 and temperature sensor T3, the compressor and fan speeds are matched. The electronic expansion valve is opened gradually from its initial position at N2 steps / s until the optimal heat exchange is achieved, or the temperature difference between T1 and T2 stabilizes, or the BMS cooling request mode changes. The optimal heat exchange is the optimal solution for heat dissipation based on the current state and the target energy efficiency ratio.

5. The control method for the cooling system of electric engineering machinery according to claim 4, characterized in that, Acquire monitoring data from the cooling system, and determine the cab cooling demand and battery pack BMS cooling request mode based on the monitoring data, including: If both cab cooling and battery pack cooling are required, determine the cab cooling demand status and the current cooling request mode of the BMS: Acquire the cabin temperature setpoint Tcin, evaporator blower speed Sed, maximum battery pack cell temperature Tmax, and average battery pack cell temperature Tmean; When the cabin temperature setpoint Tcin ≤ temperature limit Tdin, the evaporator blower setting Sed ≥ calibration setting Sbe, the highest cell temperature Tmax ≥ lower limit of cooling threshold Tdow, and the average cell temperature Tmean ≥ lower limit of cooling threshold equilibrium point Tpow, the cabin cooling is in a state of high demand, and the battery management system (BMS) will request slow cooling mode.

6. The control method for the cooling system of electric engineering machinery according to claim 5, characterized in that, Based on the cab's cooling demand and the battery pack BMS cooling request mode, execute the corresponding cooling commands, including: When the cab cooling is in high demand and the Battery Management System (BMS) requests slow cooling mode, the compressor is turned on and the electronic expansion valve is turned off. Based on the system refrigerant pressure and evaporator surface temperature fed back by pressure sensor P1 and temperature sensor T3, adjust the fan speed to the corresponding speed. Turn on the variable frequency water pump and adjust it to 50% speed. The circuit will switch to the first branch via a solenoid valve. The coolant will pass through the battery radiator, exchange heat with the second fan, and then be cooled by the battery pack. The battery pack inlet and outlet coolant temperature feedback values ​​T1 and T2 are calculated comprehensively, and the fan speed is dynamically adjusted until the temperature difference between T1 and T2 tends to stabilize or the BMS cooling request mode changes.

7. The control method for the cooling system of electric engineering machinery according to claim 6, characterized in that, Acquire monitoring data from the cooling system, and determine the cab cooling demand and battery pack BMS cooling request mode based on the monitoring data, including: If both cab cooling and battery pack cooling are required, determine the cab cooling demand status and the current cooling request mode of the BMS: Acquire the cabin temperature setpoint Tcin, evaporator blower speed Sed, maximum battery pack cell temperature Tmax, and average battery pack cell temperature Tmean; When the cabin temperature setpoint Tcin is greater than or equal to the temperature limit Tdin, and the evaporator blower setting Sed is less than or equal to the calibrated setting Sbe, the highest battery pack cell temperature Tmax is greater than or equal to the upper limit of the cooling threshold Ttop, and the average battery pack cell temperature Tmean is greater than or equal to the upper limit of the cooling threshold equilibrium point Tpoi, the cabin cooling is in a weak demand state, and the battery management system (BMS) will request the fast cooling mode.

8. The control method for the cooling system of electric engineering machinery according to claim 7, characterized in that, Based on the cab's cooling demand and the battery pack BMS cooling request mode, execute the corresponding cooling commands, including: When the cab cooling is in a low-demand state, the Battery Management System (BMS) will request the fast cooling mode. It will then calculate the battery pack inlet and outlet coolant temperature feedback values ​​T1 and T2, and increase the water pump speed to achieve the maximum flow rate. Based on the system refrigerant pressure and evaporator surface temperature fed back by pressure sensor P1 and temperature sensor T3, the compressor and condenser fan speeds are matched. The electronic expansion valve opening is initialized and gradually opened at N3 steps / s until the optimal heat exchange is reached, or the temperature difference between T1 and T2 tends to stabilize, or the BMS cooling request mode changes; the optimal heat exchange is the optimal solution of the heat dissipation state based on the current state and the target energy efficiency ratio.

9. The control method for the cooling system of electric engineering machinery according to any one of claims 1, 2, 4, 6, and 8, characterized in that, The method for comprehensively calculating the battery pack inlet and outlet coolant temperature feedback values ​​T1 and T2 includes: adding 2 degrees to the inlet and outlet temperature monitoring values ​​collected by the sensor as the battery pack inlet and outlet coolant temperature feedback values ​​T1 and T2.

10. The control method for the cooling system of electric engineering machinery according to claim 2, characterized in that, Acquire monitoring data from the cooling system, and determine the cab cooling demand and battery pack BMS cooling request mode based on the monitoring data, including: If both cab cooling and battery pack cooling are required, determine the cab cooling demand status and the current cooling request mode of the BMS: Acquire the cabin temperature setpoint Tcin, evaporator blower speed Sed, maximum battery pack cell temperature Tmax, and average battery pack cell temperature Tmean; When the cabin temperature setpoint Tcin is greater than or equal to the temperature limit Tdin, and the evaporator blower setting Sed is less than or equal to the calibrated setting Sbe, the highest cell temperature Tmax is greater than or equal to the lower limit of the cooling threshold Tdow, and the average cell temperature Tmean is greater than or equal to the lower limit of the cooling threshold equilibrium point Tpow, the cabin cooling is in a weak demand state, and the battery management system (BMS) will request a slow cooling mode.

11. The control method for the cooling system of electric engineering machinery according to claim 10, characterized in that, Based on the cab's cooling demand and the battery pack BMS cooling request mode, execute the corresponding cooling commands, including: When the cab cooling demand is low, the Battery Management System (BMS) will request slow cooling mode and activate the compressor. Adjust the fan speed according to the monitored temperature of the electric drive radiator. Turn on the variable frequency water pump and adjust it to 50% speed. Adjust the solenoid valve to switch the battery cooling circuit to the first branch, so that the coolant passes through the battery radiator, exchanges heat through the second fan, and then cools the battery pack.

12. The control method for the cooling system of electric engineering machinery according to claim 2, characterized in that, The method further includes: When the battery pack is not started, the variable frequency water pump is controlled to be at its initial speed, and then switched to the second branch through the solenoid valve, so that the coolant is in a self-circulating state.

13. A cooling system for electric engineering machinery, characterized in that, include: The monitoring system is used to acquire monitoring data of the cooling system; A controller is configured to execute the control method as described in any one of claims 1-12 based on the monitoring data.

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