Dual-compressor indirect drive control method for electric vehicle thermal management system

Abstract

The present invention provides a dual-compressor indirect drive device and a control method for an electric vehicle thermal management system. The motor controller (2) is connected to the motor (1); the motor (1) is respectively connected to the first motor end pulley (11) and the second motor end pulley (12) through the first motor drive shaft (9) and the second motor drive shaft (10); the first motor end pulley (11) is connected to the first compressor clutch (7) through the first drive belt (13); the first compressor clutch (7) is connected to the first compressor (3); the second motor end pulley (12) is connected to the second compressor clutch (8) through the second drive belt (14); the second compressor clutch (8) is connected to the second compressor (4).

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle thermal management. Specifically, it relates to an indirect drive control method for a dual-compressor in an electric vehicle thermal management system. More specifically, it relates to a dual-compressor indirect drive device and control method for an electric vehicle thermal management system. Background Art

[0002] Since electric vehicles have an increasingly shorter requirement for charging time, the charging power is getting larger and larger, and the vehicle thermal management system is required to have more refrigeration capacity to balance the heat generated by fast charging. There are two ways to increase the refrigeration capacity of the thermal management system. One is to increase the displacement of the compressor, thereby increasing the refrigeration capacity of the system. However, this solution will cause control problems in the system under low-load conditions and has obvious defects. Another effective solution is to add a compressor system dedicated to battery cooling in the system. However, due to the high price of electric compressors, using two electric compressors will cause cost pressure on automobile manufacturers.

[0003] Patent document CN113511043A (application number: 202110517330.8) discloses an electric vehicle thermal management system with a dual-compressor, including: a carbon dioxide thermal management module and a secondary refrigerant thermal management module. The carbon dioxide thermal management module is used for heating the cockpit and cooling the power battery, and the secondary refrigerant thermal management module is used for cooling the cockpit. This patent mainly describes an automotive thermal management system using two refrigerants and two compressors. The present invention mainly describes how to drive two compressors with one motor and the specific method to achieve that the refrigeration capacity of the compressor corresponding system meets the heat load demand.

[0004] Patent document CN215292792U (application number: 202120984130.9) discloses a single-motor-driven dual-air-compressor unit structure, including a bracket, a motor, two air compressors, and two sets of transmission belts. The bracket is provided with three platforms stacked at intervals in sequence; the motor is fixed on the middle platform, and a runner is provided at the end of the motor output shaft. The runner is provided with two sets of limit grooves; the two air compressors are respectively fixed on the upper and lower platforms; one set of transmission belts is sleeved on the main shaft turntable of the upper air compressor and one set of limit grooves, and the other set of transmission belts is sleeved on the main shaft turntable of the lower air compressor and the other set of limit grooves. This patent is used in the field of air compressors, while the present invention is used in the field of automotive air conditioners; the purpose of this patent is only to reduce the installation space, and the two compressors can only work together or stop together. At the same time, this patent uses a constant-speed motor and cannot control the displacement of the compressor.

[0005] Patent document CN108621748A (application number: 201810440516.6) discloses a dual-compressor air-conditioning control system for a refrigerated carriage, including: a first compressor, a second compressor, an air-conditioning controller, and a driving device linked to an engine; the air-conditioning controller controls the start and stop of the driving device; the started driving device enables the engine to indirectly drive the first compressor to operate and / or the second compressor to operate. This patent is used for refrigerating the carriage of a refrigerated truck, and the purpose of the dual compressors is to solve the problem of insufficient refrigerating capacity of a single compressor when the vehicle is idling; while the present invention is used for refrigerating the passenger compartment and the power battery of an electric vehicle. The control objects and control methods are completely different. This patent uses the engine as power and adjusts the rotational speed of the compressor through an intermediate driving mechanism; the present invention uses an electric motor as power and directly drives the compressor through the motor shaft. And the structures of the two are very different. Summary of the Invention

[0006] Aiming at the defects in the prior art, the purpose of the present invention is to provide a dual-compressor indirect driving device and a control method for an electric vehicle thermal management system.

[0007] A dual-compressor indirect driving device for an electric vehicle thermal management system according to the present invention includes: an electric motor 1, an electric motor controller 2, a first compressor 3, a second compressor 4, a first compressor clutch 7, a second compressor clutch 8, a first motor driving shaft 9, a second motor driving shaft 10, a first motor-end pulley 11, a second motor-end pulley 12, a first transmission belt 13, and a second transmission belt 14;

[0008] The electric motor controller 2 is connected to the electric motor 1; the electric motor 1 is respectively connected to the first motor-end pulley 11 and the second motor-end pulley 12 through the first motor driving shaft 9 and the second motor driving shaft 10; the first motor-end pulley 11 is connected to the first compressor clutch 7 through the first transmission belt 13; the first compressor clutch 7 is connected to the first compressor 3; the second motor-end pulley 12 is connected to the second compressor clutch 8 through the second transmission belt 14; the second compressor clutch 8 is connected to the second compressor 4.

[0009] Preferably, the first motor-end pulley 11 and the first compressor clutch 7 are connected through the first transmission belt 13 to drive the first compressor 3; the second motor-end pulley 12 and the second compressor clutch 8 are connected through the second transmission belt 14 to drive the second compressor 4.

[0010] Preferably, the first compressor 3 includes a first mechanical variable displacement compressor or a first mechanical fixed displacement compressor;

[0011] The second compressor 4 includes a second mechanical variable displacement compressor or a second mechanical fixed displacement compressor.

[0012] Preferably, the first motor end pulley 11 and the second motor end pulley 12 have different diameters or the same diameter as required.

[0013] The first compressor clutch 7 and the second compressor clutch 8 have different pulley diameters or the same pulley diameter as required.

[0014] According to a control method of a dual-compressor indirect drive device for an electric vehicle thermal management system provided by the present invention, the above-mentioned dual-compressor indirect drive device for an electric vehicle thermal management system is used to perform the following operations:

[0015] Step S1: Control the working or non-working state of the compressor by controlling the energization or de-energization of the compressor clutch.

[0016] Step S2: Determine whether the refrigerating capacity of the compressor meets the thermal load requirement of the thermal management system; when the refrigerating capacity of the compressor is greater than or less than the thermal load requirement of the thermal management system, control the displacement of the compressor to meet the thermal load requirement of the thermal management system.

[0017] Preferably, in step S1, by controlling the energization and de-energization of the first compressor clutch 7 and the second compressor clutch 8, control any one compressor to work alone or control the two compressors to work together. When neither of the two compressors needs to work, control the motor 1 to stop.

[0018] Preferably, in step S2, determine whether the refrigerating capacity of the compressor meets the thermal load requirement of the thermal management system by measuring the outlet air temperature of the air conditioning box and the outlet water temperature of the battery cooler.

[0019] Preferably, step S2 adopts:

[0020] When only one compressor is working, based on the calibrated ambient temperature-thermal management system thermal load-compressor speed parameter curve, control the initial speed of the motor 1 through the motor controller 2. When the refrigerating capacity of the compressor is greater than the thermal load of the thermal management system, reduce the speed of the motor 1 until the inflection point where the refrigeration demand of the thermal management system cannot be met appears, and then increase the speed of the motor 1 to keep it running at the inflection point speed; when the refrigerating capacity of the compressor is less than the thermal load of the thermal management system, increase the speed of the motor 1 until the inflection point where the refrigeration demand of the thermal management system can be met appears, and keep the motor 1 running at the inflection point speed.

[0021] When the two compressors work simultaneously, the rotational speed requirement of the compressor corresponding to the thermal management system with a larger heat load is preferentially satisfied, and the motor (1) operates based on the inflection point rotational speed of the compressor; when the other compressor corresponding to the thermal management system with a smaller heat load is a mechanical fixed displacement compressor, the on / off of the clutch is controlled to make it fit the refrigeration demand of the thermal management system; when the other compressor corresponding to the thermal management system with a smaller heat load is a mechanical variable displacement compressor, the mechanical variable displacement compressor automatically reduces the displacement per revolution to maintain the corresponding compressor refrigeration capacity equal to the heat load of the corresponding thermal management system.

[0022] Preferably, when the pulley on the motor end is larger than the pulley of the compression clutch, the rotational speed of the compressor is higher than that of the motor. By controlling the transmission ratio between the pulley on the motor end and the pulley on the compressor clutch, the displacement of the compressor is controlled, thereby controlling the refrigeration capacity of the compressor.

[0023] According to a control method for a dual-compressor indirect drive device for an electric vehicle thermal management system provided by the present invention, the following operations are performed using the above-mentioned dual-compressor indirect drive device for an electric vehicle thermal management system:

[0024] Step M1: Calibrate the thermal management system to determine the required rotational speed of the motor that can meet the maximum heat load of any thermal management system.

[0025] Step M2: The motor operates based on the required rotational speed, and the mechanical variable displacement compressor adjusts its displacement by itself to fully fit the refrigeration demand of the corresponding thermal management system; and / or the mechanical fixed displacement compressor satisfies the refrigeration demand of the thermal management system by controlling the on / off of the clutch.

[0026] The mechanical variable displacement compressor adjusts the displacement per revolution by itself through a built-in control valve, so that the reduced compressor displacement maintains the corresponding compressor refrigeration capacity equal to the heat load of the thermal management system.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The present invention adopts a solution of combining an electric motor with a variable displacement compressor. It can not only adjust the displacement of the compressor by adjusting the motor speed, but also adjust the displacement through the control valve inside the compressor, increasing the adjustment range of the compressor displacement, better adapting to the heat load requirements of different systems, and reducing the difficulty of system calibration. In some low-load working conditions, it is not necessary for the compressor to output a large amount of refrigerating capacity. However, due to the limitation of the minimum speed of 800 - 1000 rpm for the electric compressor, the displacement cannot be further reduced for output, resulting in an increase in energy consumption. For example, there are two compressors with similar maximum refrigerating capacities. One is a mechanical variable displacement compressor with 150 cc / r (the maximum displacement is calculated based on a speed of 3000 rpm and a volumetric efficiency of 60%), and the other is an electric compressor with 34 cc / r (the maximum displacement is calculated based on a speed of 8000 rpm and a volumetric efficiency of 90%). The variable displacement compressor can be adjusted through the control valve to reach a minimum displacement of about 10 cc / r. At a speed of 1000 rpm, its minimum displacement can reach 10000 cc / min, while the displacement of the electric compressor is 34000 cc / min;

[0029] 2. The external electric motor solution adopted by the present invention can improve the working environment of the electric motor and its controller. The insulation design of the electric motor does not need to consider the influence of refrigerant and lubricating oil, and the cooling of the electric motor is not affected by the refrigerant flow rate, increasing the reliability and durability of the electric motor;

[0030] 3. The mechanical compressors adopted by the present invention have complete specifications and mature technologies; while the specifications of electric compressors are less, and the technologies are not yet fully mature and are in a state of being to be improved and perfected;

[0031] 4. The control parameter of the present invention is only the speed of one electric motor. For the solution of dual electric compressors, the speeds of the two compressors need to be controlled separately. Adopting the present invention simplifies the calibration objects required by the control system and reduces the calibration workload;

[0032] 5. The present invention adopts a solution of using one electric motor to control two mechanical compressors. Compared with the solution of using two electric compressors, on the premise of meeting the same technical performance requirements, it can reduce the cost of the electric vehicle thermal management system;

[0033] 6. According to the different performance and cost requirements of the thermal management system, appropriate dual-compressor combinations can be selected to perfectly meet the user's needs. For example, for a thermal management system that has control accuracy requirements for both the air outlet temperature of the air conditioner box and the cooling water outlet temperature of the battery, a dual variable displacement compressor combination can be adopted; for some projects with low requirements for temperature control accuracy but sensitive to cost, a combination of dual fixed displacement compressors and a fixed speed electric motor can be adopted, and even the electric motor controller can be omitted. Description of the Drawings

[0034] Other features, objects, and advantages of the present invention will become more apparent from the following detailed description of non-limiting embodiments read in conjunction with the accompanying drawings:

[0035] Figure 1 Schematic diagram of the basic structure of the dual-compressor system provided by the present invention.

[0036] Figure 2 Schematic diagram of the control method of the present invention in the dual-compressor combination-1 state.

[0037] Figure 3 Schematic diagram of the control method of the present invention in the dual-compressor combination-2 state.

[0038] Figure 4 Schematic diagram of the control method of the present invention in the dual-compressor combination-3 state. Detailed implementation manners

[0039] The present invention will be described in detail below in conjunction with specific embodiments. The following embodiments will help those skilled in the art to further understand the present invention, but do not limit the present invention in any form. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present invention, several changes and improvements can still be made. These all belong to the protection scope of the present invention.

[0040] Aiming at the defects of the dual-electric compressor system in the prior art, the technical problems to be solved by the present invention are reflected in the following aspects:

[0041] 1. The present invention adopts a scheme of a motor combined with a variable displacement compressor, which solves the defect that the refrigeration capacity of the existing electric compressor scheme cannot fully match the system heat load under low load conditions, and reduces energy consumption;

[0042] 2. The motor external scheme adopted by the present invention solves the problem that the cooling performance of the electric compressor motor is affected by the refrigerant flow rate, and increases the reliability and durability of the motor;

[0043] 3. The mechanical compressor adopted by the present invention has complete specifications and mature technology; it solves the problem of few specifications and difficult selection of electric compressors;

[0044] 4. The compressor control parameter of the present invention is only the speed of one motor. Compared with the dual-electric compressor scheme, it simplifies the calibration objects required by the control system and reduces the calibration work;

[0045] 5. The various dual-compressor combinations proposed by the present invention increase the selection range of technical solutions for the thermal management system.

[0046] Example 1

[0047] A dual-compressor indirect drive device for an electric vehicle thermal management system provided according to the present invention, as Figure 1 shown, includes: a motor 1, a motor controller 2, a first compressor 3, a second compressor 4, a first compressor clutch 7, a second compressor clutch 8, a first motor drive shaft 9, a second motor drive shaft 10, a first motor-end pulley 11, a second motor-end pulley 12, a first drive belt 13, and a second drive belt 14;

[0048] The motor controller 2 is connected to the motor 1; the motor 1 is respectively connected to the first motor-end pulley 11 and the second motor-end pulley 12 through the first motor drive shaft 9 and the second motor drive shaft 10; the first motor-end pulley 11 is connected to the first compressor clutch 7 through the first drive belt 13; the first compressor clutch 7 is connected to the first compressor 3; the second motor-end pulley 12 is connected to the second compressor clutch 8 through the second drive belt 14; the second compressor clutch 8 is connected to the second compressor 4.

[0049] Specifically, the first motor-end pulley 11 and the first compressor clutch 7 are connected through the first drive belt 13 to drive the first compressor 3; the second motor-end pulley 12 and the second compressor clutch 8 are connected through the second drive belt 14 to drive the second compressor 4.

[0050] Specifically, the first compressor 3 includes a first mechanical variable displacement compressor or a first mechanical fixed displacement compressor;

[0051] The second compressor 4 includes a second mechanical variable displacement compressor or a second mechanical fixed displacement compressor.

[0052] Specifically, the first motor-end pulley 11 and the second motor-end pulley 12 may have different diameters or the same diameter as needed;

[0053] The first compressor clutch 7 and the second compressor clutch 8 may have different pulley diameters or the same pulley diameter as needed. By selecting the transmission ratio between the motor-end pulley and the pulley on the compressor clutch, the speed of the motor can be appropriately reduced, or the problem of insufficient displacement of existing specification compressors can be appropriately compensated for.

[0054] Specifically, when the pulley on the motor side is larger than the pulley of the compression clutch, the rotational speed of the compressor is higher than that of the motor. By controlling the transmission ratio between the pulley on the motor side and the pulley on the compressor clutch, the displacement of the compressor is controlled, thereby controlling the refrigerating capacity of the compressor. For example: There are 2 types of off-the-shelf compressors. One is a compressor with a displacement of 130 cc / r, and the other is a compressor with a displacement of 150 cc / r. The actual required displacement of the compressor is 140 cc / r (at 2000 rpm). To save the cost of the compressor, a compressor with a displacement of 130 cc / r is selected, and a transmission ratio of 1.077 is selected. In this way, when the motor speed remains at 2000 rpm, the rotational speed of the compressor increases to 2154 rpm, meeting the refrigerating capacity requirement, and there is no need to select a compressor with a displacement of 150 cc / r. Conversely, if the transmission ratio is increased and the refrigerating displacement of the compressor is increased, and the refrigerating capacity is surplus, the rotational speed of the motor can be appropriately reduced.

[0055] Specifically, by controlling the energization and de-energization of the first compressor clutch 7 and the second compressor clutch 8, any one compressor can be controlled to work alone or the two compressors can be controlled to work together. When neither of the two compressors needs to work, the motor 1 is controlled to stop. For example: The refrigerant system where one compressor is located is responsible for the passenger compartment air conditioner, and the refrigerant system where the other compressor is located is responsible for battery cooling. When there is only one of the demands of air conditioning or battery cooling, only the system where 1 compressor is located works alone; when both demands exist simultaneously, the two systems where the 2 compressors are located need to work simultaneously.

[0056] Example 2

[0057] Embodiment 2 is a preferred example of Embodiment 1

[0058] According to a control method of a dual-compressor indirect drive device for an electric vehicle thermal management system provided by the present invention, the following operations are performed by using the above-mentioned dual-compressor indirect drive device for an electric vehicle thermal management system:

[0059] Step S1: Control the working or non-working state of the compressor by controlling the energization or de-energization of the compressor clutch;

[0060] Step S2: Determine whether the refrigerating capacity of the compressor meets the heat load demand of the thermal management system; when the refrigerating capacity of the compressor is greater than or less than the heat load demand of the thermal management system, control the displacement of the compressor to meet the heat load demand of the thermal management system.

[0061] When the dual compressors are two mechanical variable displacement compressors

[0062] Such as Figure 2As shown, in the dual-compressor combination - 1, between the first motor-end pulley 11 of the motor 1 and the first compressor clutch 7, they are connected by the first drive belt 13 to drive the first mechanical variable-displacement compressor; between the second motor-end pulley 12 of the motor 1 and the second compressor clutch 8, they are connected by the second drive belt 14 to drive the second mechanical variable-displacement compressor. By controlling the energization and de-energization of the first compressor clutch 7 and the second compressor clutch 8, either compressor can work alone, or both compressors can work together. When neither compressor needs to work, the motor 1 stops.

[0063] When only one compressor is working, referring to the pre-calibrated ambient temperature - system heat load - compressor speed parameter curve, through the motor controller 2, control the initial speed of the motor 1. If the refrigeration capacity of the compressor is greater than the system heat load, then reduce the speed of the motor 1 until the inflection point where the system refrigeration demand cannot be met appears, and then increase the speed of the motor 1 to keep it running at the inflection point speed. If the refrigeration capacity of the compressor is less than the system heat load, then increase the speed of the motor 1 until the inflection point where the system refrigeration demand can be met appears, and then keep the motor 1 running at the inflection point speed.

[0064] When both compressors need to work simultaneously, referring to the pre-calibrated ambient temperature - system heat load - compressor speed parameter curve, according to the demand of the system with the larger heat load, through the motor controller 2, control the initial speed of the motor 1. If the refrigeration capacity of the compressor corresponding to the system with the larger heat load is greater than the system heat load, then reduce the speed of the motor 1 until the inflection point where the system refrigeration demand cannot be met appears, and then increase the speed of the motor 1 to keep it running at the inflection point speed. If the refrigeration capacity of the compressor is less than the system heat load, then increase the speed of the motor 1 until the inflection point where the system refrigeration demand can be met appears, and then keep the motor 1 running at the inflection point speed. When the motor 1 is running at the inflection point speed, only one compressor can fully meet the system refrigeration demand. At this time, the other compressor corresponding to the system with the smaller heat load can adjust its displacement by itself to fully meet the system refrigeration demand.

[0065] There is also a control method that reduces costs and control difficulty but increases energy consumption. Through the previous system calibration, determine the speed required for the motor to meet the maximum heat load of any system, and then select a constant-speed motor to make the motor always work at this speed. Both compressors adjust their displacements by themselves to fully meet the corresponding system refrigeration demands.

[0066] When the dual compressors are one mechanical variable-displacement compressor and one mechanical fixed-displacement compressor

[0067] Such as Figure 3As shown, in the dual-compressor combination-2, between the first motor-end pulley 11 of the motor 1 and the first compressor clutch 7, they are connected by the first drive belt 13 to drive the first mechanical variable-displacement compressor; between the second motor-end pulley 12 of the motor 1 and the second compressor clutch 8, they are connected by the second drive belt 14 to drive the second mechanical fixed-displacement compressor. By controlling the energization and de-energization of the first compressor clutch 7 and the second compressor clutch 8, either compressor can work alone, or both compressors can work together. When neither compressor needs to work, the motor 1 stops.

[0068] When only one variable-displacement compressor is working, referring to the pre-calibrated ambient temperature-system heat load-compressor speed parameter curve, through the motor controller 2, control the initial speed of the motor 1. If the refrigerating capacity of the compressor is greater than the system heat load, then reduce the speed of the motor 1 until the inflection point where the system refrigeration demand cannot be met appears, and then increase the speed of the motor 1 to keep it running at the inflection point speed. If the refrigerating capacity of the compressor is less than the system heat load, then increase the speed of the motor 1 until the inflection point where the system refrigeration demand can be met appears, and then keep the motor 1 running at the inflection point speed.

[0069] When only one fixed-displacement compressor is working, referring to the pre-calibrated ambient temperature-system heat load-compressor speed parameter curve, through the motor controller 2, control the initial speed of the motor 1. If the refrigerating capacity of the compressor is greater than the system heat load, then reduce the speed of the motor 1 until the inflection point where the system refrigeration demand cannot be met appears, and then increase the speed of the motor 1 to keep it running at the inflection point speed. If the refrigerating capacity of the compressor is less than the system heat load, then increase the speed of the motor 1 until the inflection point where the system refrigeration demand can be met appears, and then keep the motor 1 running at the inflection point speed.

[0070] When both compressors need to work simultaneously, referring to the pre-calibrated ambient temperature-system heat load-compressor speed parameter curve, according to the demand of the system with the larger heat load, through the motor controller 2, control the initial speed of the motor 1. If the refrigerating capacity of the compressor corresponding to the system with the larger heat load is greater than the system heat load, then reduce the speed of the motor 1 until the inflection point where the system refrigeration demand cannot be met appears, and then increase the speed of the motor 1 to keep it running at the inflection point speed. If the refrigerating capacity of the compressor is less than the system heat load, then increase the speed of the motor 1 until the inflection point where the system refrigeration demand can be met appears, and then keep the motor 1 running at the inflection point speed. When the motor 1 is running at the inflection point speed, only one compressor can fully meet the system refrigeration demand. At this time, for the other compressor corresponding to the system with the smaller heat load, if it is a variable-displacement compressor, it can adjust its displacement by itself to fully meet the system refrigeration demand; if it is a fixed-displacement compressor, it can be made to meet the system refrigeration demand by controlling the on-off of the clutch.

[0071] There is also a control method that reduces costs and control difficulty but increases energy consumption. Through the pre-system calibration, determine the required speed of the motor that can meet the maximum heat load of any system. Then, select a constant-speed motor so that the motor always operates at this speed. The variable-displacement compressor adjusts its displacement automatically to fully match the corresponding system's refrigeration demand; the fixed-displacement compressor meets the system's refrigeration demand by controlling the on-off of the clutch.

[0072] When the dual compressors are two mechanical fixed-displacement compressors

[0073] As Figure 4 shown, in the dual-compressor combination - 3, between the first motor-end pulley 11 of the motor 1 and the first compressor clutch 7, they are connected by the first drive belt 13 to drive the first mechanical fixed-displacement compressor 5; between the second motor-end pulley 12 of the motor 1 and the second compressor clutch 8, they are connected by the second drive belt 14 to drive the second mechanical fixed-displacement compressor 6;. By controlling the energization and de-energization of the first compressor clutch 7 and the second compressor clutch 8, either compressor can work alone, or both compressors can work together. When neither compressor needs to work, the motor 1 stops.

[0074] When only one fixed-displacement compressor is working, referring to the pre-calibrated ambient temperature - system heat load - compressor speed parameter curve, through the motor controller 2, control the initial speed of the motor 1. If the refrigeration capacity of the compressor is greater than the system heat load, then reduce the speed of the motor 1 until the inflection point where the system refrigeration demand cannot be met appears, and then increase the speed of the motor 1 to keep it running at the inflection point speed. If the refrigeration capacity of the compressor is less than the system heat load, then increase the speed of the motor 1 until the inflection point where the system refrigeration demand can be met appears, and then keep the motor 1 running at the inflection point speed.

[0075] When two fixed-displacement compressors need to work simultaneously, referring to the pre-calibrated ambient temperature - system heat load - compressor speed parameter curve, according to the demand of the system with the larger heat load, through the motor controller 2, control the initial speed of the motor 1. If the refrigeration capacity of the compressor corresponding to the system with the larger heat load is greater than the system heat load, then reduce the speed of the motor 1 until the inflection point where the system refrigeration demand cannot be met appears, and then increase the speed of the motor 1 to keep it running at the inflection point speed. If the refrigeration capacity of the compressor is less than the system heat load, then increase the speed of the motor 1 until the inflection point where the system refrigeration demand can be met appears, and then keep the motor 1 running at the inflection point speed. When the motor 1 is running at the inflection point speed, only one compressor can fully match the system refrigeration demand. At this time, for the other compressor corresponding to the system with the smaller heat load, it can be made to match the system refrigeration demand by controlling the on-off of the clutch.

[0076] There is also a control method that reduces costs and control difficulty but increases energy consumption. Through the pre-system calibration, determine the rotational speed required for the motor that can meet the maximum heat load of any system. Then, select a fixed-speed motor so that the motor always operates at this rotational speed. Both fixed-displacement compressors meet the refrigeration requirements of the system by controlling the on / off of the clutch.

[0077] Among them, the pre-system calibration is carried out as follows: In environments with various temperatures, humidities, and vehicle speeds, the heat load that the refrigerant system needs to balance is different. Therefore, it is necessary to conduct tests under various combinations of vehicle speeds, temperatures, and humidities in a wind tunnel laboratory where the ambient temperature, humidity, vehicle speed, and vehicle head-on wind speed can be controlled. The combined working conditions include common working conditions and extreme working conditions. This kind of test is the system calibration test. When conducting the calibration test, the calibrated rotational speed of the compressor under each working condition in the combined working conditions can be found. At this rotational speed, the refrigeration capacity of the compressor can just balance the system heat load.

[0078] In the description of the present application, it should be understood that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present application.

[0079] Those skilled in the art know that in addition to implementing the systems, devices, and their respective modules provided by the present invention in the form of pure computer-readable program codes, the method steps can be logically programmed to enable the systems, devices, and their respective modules provided by the present invention to be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers, etc. to achieve the same program. Therefore, the systems, devices, and their respective modules provided by the present invention can be regarded as a kind of hardware component, and the modules included therein for implementing various programs can also be regarded as the structure within the hardware component; the modules for implementing various functions can also be regarded as either software programs for implementing the method or the structure within the hardware component.

[0080] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the above specific embodiments, and those skilled in the art can make various changes or modifications within the scope of the claims, which does not affect the essence of the present invention. Without conflict, the embodiments of the present application and the features in the embodiments can be combined with each other arbitrarily.

Claims

1. A control method for a dual-compressor indirect drive device of an electric vehicle thermal management system, characterized in that, The following operations are performed using a dual-compressor indirect drive device for an electric vehicle thermal management system: The dual-compressor indirect drive device for an electric vehicle thermal management system includes: a motor (1), a motor controller (2), a first compressor (3), a second compressor (4), a first compressor clutch (7), a second compressor clutch (8), a first motor drive shaft (9), a second motor drive shaft (10), a first motor-end pulley (11), a second motor-end pulley (12), a first drive belt (13), and a second drive belt (14); The motor controller (2) is connected to the motor (1); the motor (1) is respectively connected to the first motor-end pulley (11) and the second motor-end pulley (12) through the first motor drive shaft (9) and the second motor drive shaft (10); the first motor-end pulley (11) is connected to the first compressor clutch (7) through the first drive belt (13); the first compressor clutch (7) is connected to the first compressor (3); the second motor-end pulley (12) is connected to the second compressor clutch (8) through the second drive belt (14); the second compressor clutch (8) is connected to the second compressor (4); The control method of the dual-compressor indirect drive device for an electric vehicle thermal management system includes: Step S1: Control the working or non-working state of the compressor by controlling the power-on or power-off of the compressor clutch; Step S2: Determine whether the refrigerating capacity of the compressor meets the thermal load requirement of the thermal management system; when the refrigerating capacity of the compressor is greater than or less than the thermal load requirement of the thermal management system, control the displacement of the compressor to meet the thermal load requirement of the thermal management system; The step S2 adopts: When only one compressor is working, based on the calibrated ambient temperature-thermal management system thermal load-compressor speed parameter curve, the motor controller (2) controls the initial speed of the motor (1). When the refrigerating capacity of the compressor is greater than the thermal load of the thermal management system, reduce the speed of the motor (1) until the inflection point where the refrigeration demand of the thermal management system cannot be met appears, and then increase the speed of the motor (1) to keep it running at the inflection point speed; when the refrigerating capacity of the compressor is less than the thermal load of the thermal management system, increase the speed of the motor (1) until the inflection point where the refrigeration demand of the thermal management system can be met appears, and keep the motor (1) running at the inflection point speed; When both compressors are working simultaneously, preferentially meet the speed demand of the compressor corresponding to the thermal management system with a larger thermal load. The motor (1) runs based on the inflection point speed of the compressor. When the other compressor corresponding to the thermal management system with a smaller thermal load is a mechanical fixed-displacement compressor, control the on-off of the clutch to make it fit the refrigeration demand of the thermal management system; when the other compressor corresponding to the thermal management system with a smaller thermal load is a mechanical variable-displacement compressor, the mechanical variable-displacement compressor automatically reduces the displacement per revolution to maintain the corresponding refrigerating capacity of the compressor equal to the thermal load of the corresponding thermal management system.

2. The control method for a dual-compressor indirect drive device of an electric vehicle thermal management system according to claim 1, characterized in that, The first motor-end pulley (11) and the first compressor clutch (7) are connected by the first drive belt (13) to drive the first compressor (3); the second motor-end pulley (12) and the second compressor clutch (8) are connected by the second drive belt (14) to drive the second compressor (4).

3. The control method for a dual-compressor indirect drive device of an electric vehicle thermal management system according to claim 1, characterized in that, The first compressor (3) includes a first mechanical variable displacement compressor or a first mechanical fixed displacement compressor; The second compressor (4) includes a second mechanical variable displacement compressor or a second mechanical fixed displacement compressor.

4. The control method for a dual-compressor indirect drive device of an electric vehicle thermal management system according to claim 1, characterized in that, The first motor-end pulley (11) and the second motor-end pulley (12) may have different diameters or the same diameter as required; The first compressor clutch (7) and the second compressor clutch (8) may have different pulley diameters or the same pulley diameter as required.

5. The control method for a dual-compressor indirect drive device of an electric vehicle thermal management system according to claim 1, characterized in that, Step S1 is implemented as follows: By controlling the energization and de-energization of the first compressor clutch (7) and the second compressor clutch (8), any one of the compressors can be controlled to work alone or both compressors can be controlled to work together. When neither compressor needs to work, the motor (1) is controlled to stop.

6. The control method for a dual-compressor indirect drive device of an electric vehicle thermal management system according to claim 1, characterized in that, Step S2 is implemented as follows: Determine whether the refrigeration capacity of the compressor meets the heat load requirements of the thermal management system based on the measured outlet air temperature of the air conditioning box and the outlet water temperature of the battery cooler.

7. The control method for a dual-compressor indirect drive device of an electric vehicle thermal management system according to claim 1, characterized in that, When the motor-end pulley is larger than the pulley of the compression clutch, the rotational speed of the compressor is higher than that of the motor. By controlling the transmission ratio between the motor-end pulley and the pulley on the compressor clutch, the displacement of the compressor is controlled, thereby controlling the refrigeration capacity of the compressor.

8. A control method for a dual-compressor indirect drive device of an electric vehicle thermal management system, characterized in that, The dual-compressor indirect drive device for an electric vehicle thermal management system is used to perform the following operations: The dual-compressor indirect drive device for an electric vehicle thermal management system includes: a motor (1), a motor controller (2), a first compressor (3), a second compressor (4), a first compressor clutch (7), a second compressor clutch (8), a first motor drive shaft (9), a second motor drive shaft (10), a first motor-end pulley (11), a second motor-end pulley (12), a first drive belt (13), and a second drive belt (14); The motor controller (2) is connected to the motor (1); the motor (1) is respectively connected to the first motor-end pulley (11) and the second motor-end pulley (12) through the first motor drive shaft (9) and the second motor drive shaft (10); the first motor-end pulley (11) is connected to the first compressor clutch (7) through the first drive belt (13); the first compressor clutch (7) is connected to the first compressor (3); the second motor-end pulley (12) is connected to the second compressor clutch (8) through the second drive belt (14); the second compressor clutch (8) is connected to the second compressor (4); The control method of the dual-compressor indirect drive device for an electric vehicle thermal management system includes: Step M1: Calibrate the thermal management system to determine the required speed of the motor that can meet the maximum heat load of any thermal management system. Step M2: The motor operates based on the required speed. The mechanical variable displacement compressor adjusts its displacement automatically to fully match the refrigeration demand of the corresponding thermal management system; and / or the mechanical fixed displacement compressor meets the refrigeration demand of the thermal management system by controlling the on / off of the clutch. The mechanical variable displacement compressor adjusts the displacement per revolution automatically through an internal control valve, so that the reduced compressor displacement maintains the corresponding refrigeration capacity of the compressor equal to the heat load of the thermal management system. The following is adopted in Step M2: When only one compressor is operating, based on the calibrated ambient temperature - thermal management system heat load - compressor speed parameter curve, the motor controller (2) controls the initial speed of the motor (1). When the refrigeration capacity of the compressor is greater than the heat load of the thermal management system, the speed of the motor (1) is reduced until the inflection point where the refrigeration demand of the thermal management system cannot be met appears, and then the speed of the motor (1) is increased to keep it running at the inflection point speed; when the refrigeration capacity of the compressor is less than the heat load of the thermal management system, the speed of the motor (1) is increased until the inflection point where the refrigeration demand of the thermal management system can be met appears, and the motor (1) is kept running at the inflection point speed. When two compressors are operating simultaneously, the speed demand of the compressor corresponding to the thermal management system with the larger heat load is given priority. The motor (1) operates based on the inflection point speed of the compressor. When the other compressor corresponding to the thermal management system with the smaller heat load is a mechanical fixed displacement compressor, the on / off of the clutch is controlled to make it match the refrigeration demand of the thermal management system; when the other compressor corresponding to the thermal management system with the smaller heat load is a mechanical variable displacement compressor, the mechanical variable displacement compressor automatically reduces the displacement per revolution to maintain the corresponding refrigeration capacity of the compressor equal to the heat load of the corresponding thermal management system.

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