Dual inverter dual cycle roof mounted air conditioning system for electric vehicle

Abstract

A dual-inverter dual-cycle roof-mounted air-conditioning system for an electric vehicle may be installed in a state in which a condenser is installed as a single-core condenser in an inner space of an air-conditioning case, a first refrigeration cycle in which an inverter-type first compressor and a first evaporator are built in and a second refrigeration cycle in which an inverter-type second compressor and a second evaporator are built in are formed as independent bidirectional refrigerant paths. This ensures the required refrigeration performance with miniaturized dual compressors and reduces inverter capacity with the power topology of miniaturized dual inverters.

Description

Technical Field

[0001] The present disclosure relates to air conditioning systems for electric vehicles, and more particularly, to a high-efficiency and low-cost dual-inverter dual-cycle roof-mounted air conditioning system for electric vehicles. Background Art

[0002] Typically, air conditioning systems used to cool the interiors of electric vehicles (e.g., buses) employ the following architecture: the condenser (i.e., condenser core) and fan / motor are centrally located within the air conditioning unit, while the evaporator (i.e., evaporator core) and blower are symmetrically mounted left and right within the air conditioning housing. Air drawn in from all directions exchanges heat with the condenser core before being ejected forward along the height of the unit. This structure has been optimized and standardized for air conditioning systems used in internal combustion engine buses.

[0003] Furthermore, an air conditioning system for an electric vehicle has unique characteristics in that a compressor and a voltage converter, which are high-voltage operating components, are installed in the air conditioning unit, making it significantly different from an air conditioner for an internal combustion engine.

[0004] As a result, air conditioning systems for electric vehicles are based on the roof-mounted units used in air conditioning systems for internal combustion engine public vehicles. Furthermore, the air conditioning systems are standardized by providing a common form factor for the components of the high-voltage electric compressor and the transformer used to convert the vehicle voltage (e.g., converter and inverter).

[0005] For example, the form factor eliminates the need for complex connecting ductwork, vehicle engineering holes, and brackets between the engine compartment and the air conditioning unit. Furthermore, the form factor offers structural features that enable refrigerant to be pre-injected into the system, increasing vehicle manufacturers' units per hour (UPH) production.

[0006] Therefore, form factor is the highest priority for air conditioning systems in electric buses at this point. Form factor is also considered the standard for bus air conditioning manufacturers worldwide.

[0007] However, an air conditioning system for an electric vehicle requires optimization of an air conditioning architecture so that a compressor and a voltage converter (eg, an inverter and a converter), which account for a large proportion of component cooling performance, cost, weight, and consumed power, are installed in the air conditioning unit.

[0008] One reason is that in air conditioning systems for electric vehicles, the compressor is a scroll type compressor with a built-in AC motor, with a displacement of approximately 80 to 99 cc per revolution and a power output of 32 kW to maintain cooling comfort in buses of approximately 11 to 12 m in width. Furthermore, the compressor is mounted on a separate frame, located primarily in the empty space on the front of the air conditioner, to connect to the condenser and evaporator in a single cycle. Another reason is that a voltage converter (e.g., an inverter and converter) must be installed by securing unused space near the compressor or inside the housing to drive the compressor's AC motor and the fan's DC motor, receiving high voltage from the vehicle's battery.

[0009] In particular, air conditioning systems for electric vehicles have a greater impact on fuel efficiency and all-electric range (AER) than internal combustion engines. Furthermore, air conditioning systems are more sensitive to noise, vibration, and harshness (NVH) and are known to offer improved total cost of ownership (TCO) due to their reduced weight. Therefore, there is a need to optimize the internal architecture of air conditioning systems for electric vehicles, taking into account the three factors of ensuring target cooling performance and saving material costs, as well as power consumption reduction, vibration and noise reduction, and weight reduction.

[0010] Furthermore, as commercial public vehicles (e.g., public transportation buses) have recently faced a rapid transition to electrification, the need to optimize the air-conditioning internal architecture of the air-conditioning systems of electric public vehicles has become increasingly prominent. Summary of the Invention

[0011] In view of the above, the present disclosure relates to providing a dual-inverter dual-cycle roof-mounted air conditioning system for electric vehicles. In this air conditioning system, the following distinctive features are adopted for the internal architecture: a left / right separation structure of the single-core condenser, an integrated heat dissipation structure of the condenser / inverter / converter, an air conditioning housing bottom plate upward cooling structure of the compressor / inverter / converter, and a dual-insulated compressor mounting structure connected to the air conditioning housing connection member. In particular, the capacity of the inverter can be reduced by a power topology in which the compressor motor is rotated by dual inverters. In addition, by ensuring the required cooling performance through the dual-cycle of the dual compressor, the compressor can be miniaturized.

[0012] To achieve the above objectives, according to an embodiment of the present disclosure, a dual-inverter, dual-cycle, roof-mounted air conditioning system for an electric vehicle is provided. The air conditioning system includes a first compressor and a second compressor arranged along the width of the vehicle. The air conditioning system also includes a condenser arranged along the longitudinal direction of the vehicle. The air conditioning system also includes a first evaporator and a second evaporator arranged to the left and right of the condenser. A first refrigeration cycle including the first compressor and the first evaporator and a second refrigeration cycle including the second compressor and the second evaporator each have independent refrigerant paths in the left and right directions.

[0013] The condenser may be a single core, and an area of ​​the single core may be divided into areas used by the first refrigeration cycle and the second refrigeration cycle.

[0014] An inverter may be built in each of the first compressor and the second compressor.

[0015] A converter for driving a motor in an air conditioning system may be arranged such that a first compressor and a second compressor are located between the converter and a condenser.

[0016] The converter may be installed to be spaced a predetermined distance upward from the bottom surface of the air conditioning system. The condensing fan located above the condenser may form an air flow along the converter, the first compressor, the second compressor and the condenser from the front or rear side of the air conditioning system.

[0017] The condensing fan located above the condenser can form an air flow from the left and right sides of the air-conditioning system along the first compressor, the second compressor and the condenser.

[0018] The converter may be connected to motors of the first and second blowers installed in the installation spaces of the first and second evaporators.

[0019] The air conditioning system may further include an air conditioning housing in which each of the converter, the first compressor, the second compressor, and the condenser is mounted. The air conditioning housing may be formed with a heat dissipation area in which a space surrounding the converter, the first compressor, the second compressor, and the condenser exchanges heat with external air.

[0020] The air conditioning housing may be formed with a bottom-up tilted structure. The bottom-up tilted structure of the air conditioning housing is spaced apart from the upper surface of the vehicle body roof by forming a bottom-up tilted angle toward the center of the air conditioning housing relative to the upper surface of the vehicle body roof.

[0021] The air conditioner housing can be mounted with a converter mounting bracket on the bottom of the housing. The converter mounting bracket positions the converter at an upper height that matches the roof panel of the vehicle body. The upper and lower heights diffuse the external air flow to all four surfaces of the converter.

[0022] The air conditioner housing may form a dual-insulated compressor mounting structure within the mounting spaces for the first and second compressors. The dual-insulated compressor mounting structure may include a base member mounted on the bottom of the air conditioner housing to provide mounting spaces for each of the first and second compressors. The dual-insulated compressor mounting structure may also include compressor brackets that secure the first and second compressors to the base member, respectively.

[0023] The base member may include a compressor mounting plate on which each of the first and second compressors is positioned. The base member may also include an air conditioner housing connecting rod secured to a bottom of the air conditioner housing to support the compressor mounting plate. The compressor bracket may have an arched structure into which two bushings and two insulating members are inserted, with the compressor bracket and the compressor mounting plate forming a separation space.

[0024] Each of the bushing and the insulator may reduce compressor response characteristics of compressor rotation vibration generated when the first compressor and the second compressor are driven.

[0025] Furthermore, to achieve the aforementioned objectives, according to an embodiment of the present disclosure, a dual-inverter, dual-cycle, roof-mounted air conditioning system for an electric vehicle is provided. The air conditioning system includes: a condenser arranged at the top of the vehicle roof, parallel to a first compressor and a second compressor; a first evaporator arranged parallel to the first compressor; and a second evaporator arranged parallel to the second compressor. The refrigeration cycle has an independent bidirectional refrigerant path, comprising a first refrigeration cycle connecting the first compressor, condenser, and first evaporator; and a second refrigeration cycle connecting the second compressor, condenser, and second evaporator.

[0026] Each of the first and second refrigeration cycles may be connected to a refrigerant circulation pipe. The refrigerant circulation pipe may be arranged in the installation space of the first and second compressors behind the condenser. A thermal expansion valve (TXV) is installed on the refrigerant circulation pipe.

[0027] Compared to conventional technologies in electric utility vehicles, the dual-inverter dual-cycle roof-mounted air-conditioning system for an electric vehicle according to an embodiment of the present disclosure achieves the following operations and effects.

[0028] The first is cost reduction, which can be achieved by miniaturizing and improving major components such as compressors, inverters, and converters to reduce unit costs.

[0029] The second is weight reduction. This can be achieved by integrating a small compressor and converter with a built-in inverter, reducing the weight of each unit. Specifically, the weight reduction effect of the air conditioning system in electric buses can increase the all-electric range (AER), that is, the pure electric driving range, and has a positive impact on the durability of drive and brake components.

[0030] The third is to reduce power consumption. It turns out that when the outdoor temperature is 35℃ and the solar radiation is 830 W / m 2 Under the environmental conditions of the environment, the air-conditioning system with the distinctive features of the internal architecture reduces the power consumption by about 32% when running at maximum load for 90 minutes compared with the traditional air-conditioning system.

[0031] Fourth, it reduces the customer's total cost of ownership (TCO). This means that compressors and transformers, which account for approximately 50% or more of the cost of air conditioning units with differentiated internal architectures, can be replaced with low-cost mass-produced products based on economies of scale, thereby reducing after-sales service costs.

[0032] Fifth, vibration noise has been improved. Microphone measurements at key locations within electric buses demonstrated a reduction in noise from 77 dBc to 69 dBc (approximately 10%). Furthermore, measurements of vibrations transmitted to passenger seats or pillar ducts within the air conditioning system, which incorporates distinctive features within the interior structure, during operation showed an improvement from Juri 7- to 7+ (according to the Juri test). BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A configuration of a dual-inverter dual-cycle roof-mounted air conditioning system for an electric vehicle according to an embodiment of the present disclosure is shown.

[0034] Figure 2 A detailed configuration of a dual-inverter dual-cycle roof-mounted air conditioning system for an electric vehicle according to an embodiment of the present disclosure is shown.

[0035] Figure 3 is a block diagram illustrating an example of a configuration of a power topology including dual inverters for reducing inverter capacity for compressor motor rotation control according to an embodiment of the present disclosure.

[0036] Figure 4 is a block diagram illustrating an example of a configuration of a dual-compressor binary cycle refrigeration system for ensuring required refrigeration performance using a small compressor according to an embodiment of the present disclosure.

[0037] Figure 5 Two independent dual refrigerant path structures of a first refrigeration cycle and a second refrigeration cycle for a single-core condenser according to an embodiment of the present disclosure are shown.

[0038] Figure 6 An airflow state of a single-core condenser having two independent refrigerant paths according to an embodiment of the present disclosure is shown.

[0039] Figure 7 An integrated heat dissipation structure of a condenser, a compressor, an inverter, a fan, a motor, and a converter according to an embodiment of the present disclosure is shown.

[0040] Figure 8An example of a structure in which a compressor, an inverter, and a converter are moved upward from the bottom of an air-conditioning case to easily cool the compressor according to an embodiment of the present disclosure is shown.

[0041] Figure 9 A vibration transmission state of a compressor according to an embodiment of the present disclosure is shown.

[0042] Figure 10 An example of a dual-insulation compressor mounting structure connected to an air-conditioning case connection member according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0043] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The embodiments are examples and can be implemented in various forms by a person skilled in the art to which the present disclosure belongs. Therefore, the present disclosure is not limited to the embodiments disclosed herein.

[0044] Hereinafter, in the xyz coordinate system, the X-axis represents the longitudinal direction or the front-to-back direction of the vehicle, the Y-axis represents the width direction or the left-to-right direction of the vehicle, and the Z-axis represents the height direction or the up-down direction of the vehicle. When a component, device, element, etc. of the present disclosure is described as having a purpose or performing an operation, function, etc., the component, device, or element should be considered herein to be "configured to" satisfy that purpose or perform that operation or function.

[0045] refer to Figure 1 The roof-mounted air conditioning system 1-1 of the electric vehicle 1 includes a battery 10 and an air conditioning unit 20, which are installed (ie, assembled) on the vehicle body roof 2 along the front-rear direction of the vehicle (ie, the X axis of the xyz coordinates).

[0046] For example, the battery 10 is located at the front of the vehicle to supply power required to operate the air conditioning unit 20. The air conditioning unit 20 is located at the rear of the vehicle to perform a refrigerant cycle using power from the battery 10. In this example, the battery 10 is composed of a plurality of battery packs having a predetermined capacity to supply the required power.

[0047] Thus, the roof-mounted air conditioning system 1 - 1 cools the vehicle interior 3 by delivering cool air from the air conditioning unit 20 to the air conditioning duct 5 arranged along the vehicle roof 2 .

[0048] Specifically, the air conditioning unit 20 includes an air conditioning housing 30. The air conditioning housing 30 has an internal configuration different from a conventional configuration in that a converter 40 / inverter 51 as a voltage conversion device is arranged together with a compressor 50 for refrigerant compression, a condenser 60, an evaporator 70, and a blower 80.

[0049] For example, in the converter 40 and the inverter 51 as voltage conversion devices, the converter 40 converts the high-voltage power of the battery 10 into a DC current and supplies the DC current, and the inverter 51 converts the high-voltage power of the battery 10 into an AC current and supplies the AC current.

[0050] For example, the compressor 50 is driven by the inverter 51 to compress the low-temperature / low-pressure refrigerant and discharge the compressed refrigerant to the condenser 60 through the refrigerant circulation pipe 301 (see FIG. Figure 5 The condenser 60 utilizes a condensing fan 61 (see Figure 2 ) is operated by the blowing air to condense the high temperature / high pressure refrigerant of the compressor 50 to generate medium temperature / high pressure. The evaporator 70 evaporates the low temperature / low pressure saturated expanded refrigerant output from the condenser 60 by heat exchange with the outside air, and then re-transmits the gaseous refrigerant to the compressor 50 through the refrigerant circulation pipe 301 (see Figure 5 ).

[0051] Specifically, in the refrigerant cycle, the first and second thermal expansion valves (TXVs) 90A and 90B rapidly expand the refrigerant output from the condenser 60 , convert the refrigerant into a low-temperature / low-pressure wet saturated gas state, and deliver the converted refrigerant to the evaporator 70 .

[0052] For example, the blower 80 introduces the inside / outside air of the vehicle into the air-conditioning case 30 (see FIG. Figure 7 and Figure 8 The air inside the housing is converted into cool air by the evaporator 70 to cool the interior, and is blown into the vehicle interior 3 from the air conditioning duct 5 .

[0053] Figure 2 The figure shows the detailed structure of the air conditioning unit 20 and a roof-mounted air conditioning system 1-1. In air conditioning system 1-1, a first refrigeration cycle 300A including a first compressor 50A and a first evaporator 70A and a second refrigeration cycle 300B including a second compressor 50B and a second evaporator 70B respectively form independent refrigerant paths in the left and right directions via the first compressor 50A and the second compressor 50B arranged in the vehicle width direction. In air conditioning system 1-1, a condenser 60 is arranged in the vehicle longitudinal direction, with the first evaporator 70A and the second evaporator 70B arranged on the left and right sides of the condenser 60.

[0054] Specifically, the air conditioner housing 30 is composed of a housing tray 31, a housing upper cover 32, and a housing side cover 33. The housing tray 31 provides a component mounting portion and utilizes a vehicle body mounting bolt 7 (see FIG. Figure 10) is fastened to the vehicle body roof 2. The housing upper cover 32 covers the housing tray 31, so that the converter 40, compressor 50, condenser 60, evaporator 70, and blower 80 form an interior space that is covered from the outside. The housing side cover 33 is coupled to the middle portion between the housing tray 31 and the housing upper cover 32 to seal off the interior space.

[0055] For example, when the length in the front-to-back direction along the X-axis and the width in the left-to-right direction along the Y-axis in the xyz coordinate system are applied to a rectangular plate, the width in the left-to-right direction (the Y-axis of the xyz coordinate system) divides the housing tray 31 into three sections: a first mounting portion 31a, a second mounting portion 31b, and a central mounting portion 31c. The converter 40, compressor 50, and condenser 60 are arranged on the central mounting portion 31c in this order from the rear to the front in the front-to-back direction. The evaporator 70 and blower 80 are arranged on each of the first mounting portion 31a and the second mounting portion 31b in the front-to-back direction (i.e., the X-axis of the xyz coordinate system) so as to be parallel to the condenser 60.

[0056] In the housing tray 31, a separate frame (see Figure 9 and Figure 10 ) are installed in the empty space on the front surface of the air conditioner at regular intervals along the front-to-back direction (i.e., the X-axis direction of the xyz coordinates). This frame structure provides a portion for installing the converter 40, compressor 50, and condenser 60 and fastening them with bolts by securing an unused space within the housing.

[0057] Furthermore, the first and second mounting portions 31a and 31b of the first and second mounting portions 31a and 31b have the same shape, with a partition wall extending in the front-to-rear direction (i.e., the X-axis direction of the xyz coordinate system) to separate the mounting spaces for the evaporator 70 and the blower 80. The first mounting portion 31a is provided as a mounting space for the first evaporator 70A and the first blower 80A of the evaporator 70 and the blower 80. The second mounting portion 31b is provided as a mounting space for the second evaporator 70B and the second blower 80B of the evaporator 70 and the blower 80.

[0058] For example, the housing upper cover 32 is composed of a first cover 32a, a second cover 32b, and a central cover 32c. Each of the first cover 32a and the second cover 32b covers the first mounting portion 31a and the second mounting portion 31b of the housing tray 31. The central cover 32c covers the central mounting portion 31c of the housing tray 31.

[0059] For example, the case-side cover 33 is coupled to the converter 40 while covering the front surface of the center cover 32 c in the front-rear direction (the X-axis direction of the xyz coordinates).

[0060] In addition, the air conditioning housing 30 forms an air flow direction from the outside to the inside by using the central cover 32c of the housing upper cover 32 and the housing side cover 33 and using the external air inlets 35 and 36 (see FIG. Figure 6 、 Figure 7 and Figure 8 ).

[0061] For example, the external air intakes 35 and 36 are divided into the cover intake 35 of the center cover 32c and the side cover intake 36 of the case side cover 33. Specifically, the cover intake 35 is formed at regular intervals from the case side cover 33 across the width of the center cover 32c in the left-right direction (the Y-axis of the xyz coordinates). Meanwhile, multiple cover intakes with different lengths are formed across the length of the center cover 32c in the front-to-back direction (i.e., the X-axis of the xyz coordinates). Two side cover intakes 36 with different lengths are formed through the case side cover 33.

[0062] For example, the converter 40 is located on the central mounting portion 31 c of the case tray 31 of the air conditioning case 30 , coupled to the case side cover 33 , and electrically connected to the battery 10 to supply power to a 24V motor in the air conditioning unit 20 .

[0063] In other words, the converter 40 is arranged so that the first compressor 50A and the second compressor 50B are located between the converter 40 and the condenser 60 to drive the motor in the air conditioning system. Figure 8 As shown, the converter 40 is installed to be spaced apart from the bottom surface of the air conditioning system by a predetermined distance in an upward direction.

[0064] For example, compressor 50 is a scroll compressor, in which an AC motor consisting of two compressors, a first compressor 50A and a second compressor 50B, each with an inverter 51, is built into the central mounting portion 31c of the housing tray 31 of the air conditioning housing 30, located forward of the converter 40 (i.e., in the positive direction of the x-axis of the xyz coordinate system). The combination of first compressor 50A and second compressor 50B is configured based on the required performance (e.g., 32 kW and a displacement of 80 to 90 cc per revolution) to maintain the cooling comfort of electric vehicle 1 (e.g., an electric vehicle with an overall length of 11 to 12 meters).

[0065] Therefore, considering that doubling the inverter's power conversion capacity exponentially increases component weight and cost, first compressor 50A and second compressor 50B are constructed using dual inverters and compressors of identical specifications. Compared to large-capacity compressors in related art, this compressor and dual inverter configuration utilizes approximately half the motor's displacement and output (e.g., consuming a high-capacity power of 9 kW or more), thereby also reducing the output power capacity of inverter 51 to approximately half. Consequently, considering the customer's total cost of ownership (TCO), significant cost savings and weight reductions are achieved, while minimizing the cost of replacing components due to failures, thereby reducing the customer's total maintenance costs over the entire lifecycle.

[0066] For example, the condenser 60 is located at the center mounting portion 31c in front of the first compressor 50A and the second compressor 50B (i.e., in front of the X-axis of the xyz coordinate) of the housing tray 31 of the air conditioning housing 30. The condenser 60 is composed of a first condenser core 60A and a second condenser core 60B arranged in parallel.

[0067] In other words, the condenser 60 is a single core, and the area of ​​the single core is divided into areas used by the first refrigeration cycle and the second refrigeration cycle (see FIG. Figure 4 ).

[0068] Therefore, the condenser 60 has two independent refrigerant paths on the left and right sides of one heat exchanger, respectively, through the first condenser core 60A and the second condenser core 60B (see FIG. Figure 5 The first condenser core 60A and the second condenser core 60B are each configured with a condensation fan 61. Four condensation fans 61 are arranged at the first condenser core 60A and the second condenser core 60B to draw outside air into the interior space of the air-conditioning case 30.

[0069] In other words, the condensing fan 61 located at the top of the condenser 60 forms an airflow in the left and right directions of the air-conditioning system, and at the same time forms an airflow from the front or rear side of the air-conditioning system along the converter 40, the first compressor 50A and the second compressor 50B and the condenser 60.

[0070] First condenser core 60A and second condenser core 60B are arranged in parallel after converter 40 and compressor 50 to address all of the issues associated with conventionally arranging two condenser cores in the center of the air conditioning unit (i.e., in the middle of the x-axis direction of the xyz coordinate system). These issues include: 1) additional drain and liquid piping increase the complexity of the condenser cores, resulting in increased ventilation resistance during heat exchange; 2) empty space exists in the connection between the two condenser cores, resulting in a loss of total heat dissipation area (e.g., approximately 6% to 7%); and 3) a trade-off between increasing the width of the condenser cores and reducing the air inlet cross-section at the condenser inlet to mitigate the loss of heat dissipation area and increase in ventilation resistance.

[0071] For example, the evaporator 70 consists of a first evaporator 70A arranged in parallel with the first condenser core 60A (i.e., in front of the X-axis of the xyz coordinate) in the first mounting portion 31a of the housing tray 31 of the air-conditioning housing 30, and a second evaporator 70B arranged in parallel with the second condenser 60B (i.e., in front of the X-axis of the xyz coordinate) in the second mounting portion 31b.

[0072] The first evaporator 70A and the second evaporator 70B have the same specifications and are located on the left and right sides (see FIG. Figure 5 ) each having two independent refrigerant paths connected to one end thereof.

[0073] For example, the blower 80 consists of a first blower 80A arranged in parallel with the first evaporator 70A (i.e., in front of the X-axis of the xyz coordinate) in the first mounting portion 31a of the housing tray 31 of the air-conditioning housing 30 and a second blower 80B spaced apart from the second evaporator 70B in the second mounting portion 31b (i.e., in front of the X-axis of the xyz coordinate).

[0074] The first blower 80A and the second blower 80B have the same specifications and each form a blower group with three blowers.

[0075] Therefore, the air-conditioning unit 20 is based on the central arrangement of the condenser and the fan and the left-right symmetrical arrangement of the evaporator and the blower, and adopts a left-right separation structure of the single-core condenser; an integrated heat dissipation structure of the condenser, inverter and converter; an upward inclined structure of the bottom of the air-conditioning shell of the compressor, inverter and converter; and a double-isolated compressor mounting structure connected to the connecting member of the air-conditioning shell, which can achieve improved effects in many aspects compared to the air-conditioning architecture for internal combustion engines.

[0076] Therefore, the air conditioning unit 20 characterizes the roof-mounted air conditioning system 1 - 1 as a high-efficiency and low-cost dual-inverter roof-mounted air conditioning system 1 - 1 suitable for public vehicles among electric vehicles 1 .

[0077] Figures 3 to 10 Specifically shown are the power topology configuration of the air conditioning unit 20 , two refrigeration cycles of dual compressors, a dual refrigerant path configuration, an integrated heat dissipation configuration, and a dual isolated compressor installation configuration.

[0078] refer to Figure 3 The power topology of the air conditioning unit 20 is shown as follows: the high-voltage power of the battery 10 received from the vehicle undergoes a conversion process through the junction box 100 of the air conditioner, and is then divided into the converter 40 and the inverter 51 of the first compressor 50A and the second compressor 50B. The converter is the DC part 200B connected by the wire 201, and the inverter is the AC part 200A.

[0079] Therefore, the AC part 200A is connected to the motor loads (compressor motors) of the first compressor 50A and the second compressor 50B, and the DC part 200B is connected to the motor loads (condenser motors and blower motors) of the condensing fan 61 and the blower 80 of each condenser 60.

[0080] Specifically, based on the power consumption of a 9 kW motor, the combined power consumption of first compressor 50A and second compressor 50B is 4.5 kW or greater. Inverter 51 is 360 VAC (alternating current). Converter 40 is 24 VDC (direct current). The condenser motor (i.e., condenser fan) and blower motor each consume 1 kW of power.

[0081] refer to Figure 4 By adopting the first compressor 50A and the second compressor 50B as small compressors, the dual-compressor dual-cycle refrigeration of the air conditioning unit 20 constitutes the first refrigeration cycle 300A by the first compressor 50A and the second refrigeration cycle 300B by the second compressor 50B.

[0082] For example, the first refrigeration cycle 300A has a first cycle and is composed of a first compressor 50A, a first condenser core 60A, a first TXV 90A, and a first evaporator 70A, which form a closed loop using a refrigerant circulation pipe 301. The second refrigeration cycle 300B has a second cycle and is composed of a second compressor 50B, a second condenser core 60B, a second TXV 90B, and a second evaporator 70B, which form a closed loop using a separate refrigerant circulation pipe 301.

[0083] As described above, the first refrigeration cycle 300A and the second refrigeration cycle 300B may be composed of two completely independent cycles, thereby solving the problems of system noise and compressor sticking quality caused by the difficulty in ensuring exhaust balance between the compressors 50A and 50B.

[0084] Therefore, through the first cycle and the second cycle in the first refrigeration cycle 300A and the second refrigeration cycle 300B, when using a small-capacity compressor with half the displacement per revolution of a conventional single cycle cannot meet the refrigeration performance required by customers in tropical, Middle Eastern, hot weather regions and general temperate regions, two small-capacity compressors 50A and 50B can be used to ensure the refrigerant displacement suitable for the required refrigeration performance.

[0085] refer to Figure 5 The refrigerant circulation pipe 301 has two independent dual refrigerant paths. The first condenser core 60A and the second condenser core 60B of the condenser 60 each have two independent left and right refrigerant paths on one heat exchanger.

[0086] Therefore, the condenser 60 can allow the first compressor 50A and the first evaporator 70A to use only 50% of the core area on the left side, and also allow the second compressor 50B and the second evaporator 70B to use the remaining 50% of the core area on the right side relative to the center of the first condenser core 60A and the second condenser core 60B. In this example, the core area is calculated by multiplying the horizontal length La (i.e., the X-axis direction of the xyz coordinate) and the vertical length Lb (i.e., the Y-axis direction of the xyz coordinate) of the condenser.

[0087] Therefore, the two independent refrigerant paths structure of the refrigerant circulation pipe 301 using a single-core condenser 60 employs a condenser core having two independent refrigerant paths on the left and right sides of a single heat exchanger (i.e., a first condenser core 60A and a second condenser core 60B). Thus, the first compressor 50A and the first evaporator 70A, serving as the right compressor of the air conditioning unit 20, can constitute the right side of the condenser core relative to the center. Furthermore, the second compressor 50B and the second evaporator 70B, serving as the left compressor, can constitute the remaining left core area relative to the center of the condenser core.

[0088] Therefore, by adopting a single condenser core structure with independent bidirectional refrigerant paths, it is possible to eliminate unused areas that may occur in two independent first condenser cores 60A and second condenser cores 60B, thereby ensuring an increase in heat dissipation area. It is also possible to improve the complexity of conventional pipe connections, in which the refrigerant circulation pipe 301 crosses the center of the condenser core, thereby easily ensuring a ventilation area for smoothly introducing external air. As a result, it is possible to ensure the heat dissipation area of ​​condenser 60 and minimize ventilation resistance to air flow, thereby providing design advantages.

[0089] As mentioned above, through Figures 3 to 5As described, the power topology of controlling the motor rotation of the dual inverter type dual compressor by applying two inverters 51 to the first compressor 50A and the second compressor 50B respectively can reduce the inverter capacity, and by ensuring the refrigeration performance required for the dual cycle of the first compressor 50A and the second compressor 50B with the dual compressor, it is possible to miniaturize the compressor.

[0090] Therefore, air conditioning unit 20 can achieve the same benefits as a dual-inverter topology, ensuring a reduction in the vehicle's overall cost and weight. Customers can also minimize component replacement costs. Since even if one of first refrigeration cycle 300A and second refrigeration cycle 300B fails and becomes inoperable, the other cycle can still operate. This reduces the financial losses caused by the inevitable borrowing of fleets (transportation companies) due to a lack of cooling while the vehicle is in motion.

[0091] refer to Figure 6 The cover air intake 35 of the central cover 32c of the external air intake 35 and 36 includes a first opening 35a perforated in the front-to-rear direction (i.e., the X-axis direction of the xyz coordinate) at one side of the central cover 32c, a second opening 35b perforated in the front-to-rear direction (i.e., the X-axis direction of the xyz coordinate) at the other side of the central cover 32c (i.e., the width in the left-right direction (Y-axis direction of the xyz coordinate)), and a third opening 35c formed at the rear side of the central cover 32c (i.e., the rear side toward the X-axis of the xyz coordinate).

[0092] In other words, the air conditioning housing 30 is formed with external air inlets 35 and 36 on three of the four surfaces in the front, rear, left and right directions. When the condensing fan 61 of the condenser 60 is driven, external air is introduced through the external air inlets, and the external air inlets 35 and 36 are connected to the lower ventilation space H formed between the condenser housing 63 and the bottom of the air conditioning housing 30 at a certain interval.

[0093] Each of the first opening 35 a and the second opening 35 b has a slot structure formed into one rectangular length or two short rectangular lengths, and the third opening 35 c has a trapezoidal protrusion structure formed by the central cover 32 c and the case side cover 33 .

[0094] The condenser 60 is mounted on the central mounting portion 31c of the housing tray 31 of the air conditioning housing 30 via a condenser housing 63 surrounding the condenser core. The dimensions of the condenser housing 63 are the widths of the first and second side air intake spaces Wa and Wb, respectively, formed to the left and right of the central mounting portion 31c (the Y-axis of the xyz coordinates), and the height of the condenser housing 63, which forms the lower ventilation space H, relative to the bottom of the central mounting portion 31c (the Z-axis of the xyz coordinates).

[0095] In particular, since refrigerant circulation pipes 301 are centrally arranged in the first and second side intake spaces Wa and Wb toward first and second compressors 50A and 50B, thereby reducing the structural complexity of pipes passing through the center of a conventional core, the cross-sectional length is increased to approximately twice the conventional length of the air intake port. This increase in the cross-sectional length of the air intake port provides design advantages in terms of ensuring a ventilation area for smoothly introducing external air and minimizing ventilation resistance. This also provides a design advantage in terms of ensuring a sufficient heat dissipation area for condenser cores 60A and 60B.

[0096] Therefore, when external air is sucked into the internal space of the air-conditioning shell 30 by driving the condensing fan 61, the external air forms an air flow direction (the Z axis of the xyz coordinate) that enters the first side air intake space Wb and passes through half of the condenser cores 60A and 60B in the lower ventilation space H, and forms an air flow direction (the Z axis of the xyz coordinate) that enters the second side air intake space Wa on the opposite side and passes through the other half of the condenser cores 60A and 60B in the lower ventilation space H, which further improves the heat dissipation effect of the condenser 60.

[0097] refer to Figure 7 The external air intake ports 35 and 36 are formed on three surfaces of the air conditioning housing 30 in the front-rear direction / left-right direction: the first opening 35a and the second opening 35b on the left-right side, the third opening 35c on the rear side, and the side cover intake port 36.

[0098] Thus, the combination of the first opening 35a, the second opening 35b, and the third opening 35c with the side cover air inlet 36 forms an integrated heat dissipation structure for the converter 40, the compressor 50 (i.e., the compressor motor), the inverter 51, the condenser 60, and the condenser fan 61 (i.e., the fan motor). This integrated heat dissipation structure creates external airflow, such as rightward airflow (in the Y-axis direction of the xyz coordinates) from the outside air introduced through the first opening 35a, leftward airflow (in the Y-axis direction of the xyz coordinates) from the outside air introduced through the second opening 35b, and forward airflow (in the X-axis direction of the xyz coordinates) from the outside air introduced through the third opening 35c and the side cover air inlet 36.

[0099] Therefore, in a state where the inverter 51 built into the converter 40 and the first compressor 50A and the second compressor 50B are arranged in front of the condensing fan 61 (in the X-axis direction of the xyz coordinate), the integrated heat dissipation structure realizes integrated cooling by simultaneously introducing forward airflow (which is the forward airflow of external air introduced when the fan motor of the condensing fan 61 is running) and left and right airflow (which are the left and right side airflows in contact with all components 40, 50, 51, 60 and 61).

[0100] Specifically, compared to the conventional method of cooling the transformer (converter 40 and inverter 51) by mounting the transformer in the first mounting portion 31a and the second mounting portion 31b of the mounting space of the first evaporator 70A and the second evaporator 70B of the housing tray 31, the integrated cooling method not only provides a cooling effect for the converter 40 and the inverter 51, the temperature of which increases rapidly due to an increase in the consumed current under high load conditions and the size of the evaporator heat exchanger increases since the main components (i.e., the converter 40, the compressor 50 and the inverter 51) are mounted outside the mounting space of the first evaporator 70A and the second evaporator 70B, but also provides a direct heat removal effect of the internal cooling airflow that occurs when cooling the transformer (i.e., the converter 40 and the inverter 51).

[0101] refer to Figure 8 The air conditioning housing 30 adopts a structure in which the bottom of the air conditioning housing is inclined upward, so that the converter 40 and the inverter 51 can be easily cooled by an integrated cooling method.

[0102] As shown in the figure, the upward inclined structure of the bottom of the air-conditioning shell is formed by the shell tray 31, and the shell tray 31 is constructed into a structure in which each of the first mounting part 31a and the second mounting part 31b of the shell tray 31 components is inclined at an upward bottom angle α toward the central mounting part 31c, and a lower space is formed at the central mounting part 31c at an end height hb, and the upward bottom inclination angle is an acute angle.

[0103] Furthermore, the structure in which the bottom of the air conditioner housing is tilted upward employs a converter mounting bracket 41. The converter mounting bracket 41, while being fastened to the central mounting portion 31c of the housing tray 31 with bolts, elevates the converter 40 to a predetermined mounting height ha as high as possible. In this example, the mounting height ha is set so as to allow the converter 40 to be mounted at a position aligned with the top plate 2a of the vehicle roof 2 (see FIG. 1 ). Figure 1 and Figure 9 ) at a height that matches the

[0104] exist Figure 8 In section AA, in the upwardly inclined structure at the bottom of the air-conditioning housing, when the converter 40 is cooled by heat exchange with the external air introduced from the front surface of the air-conditioning through the third opening 35c and the side cover air inlet 36 by the operation of the condensing fan 61, the converter 40 is fully moved from the lower end of the air-conditioning housing to the installation height ha so that the heat exchange surface of the converter housing is extended to all surfaces (i.e., four surfaces), including the upper end surface, left and right surfaces and the lower end surface, thereby maximizing the cooling effect.

[0105] In addition, the external airflow that exchanges heat with all surfaces (i.e., four surfaces) of the converter 40 passes through the lower ventilation space H between the central mounting portion 31c of the shell tray 31 and the condenser shell 63 of the condenser 60, passes through the condenser core, and is discharged upward, thereby achieving a cooling effect.

[0106] refer to Figure 9 The housing tray 31 assembled to the first and second compressors 50A and 50B is fastened together with the air conditioning housing gasket 37 to the vehicle body mounting bolts 7 , which are hardware positioned on a roof panel placed on the vehicle body roof cover 2 and formed on the vehicle body frame.

[0107] As shown in the figure, when considering the direction of transmission of the compressor rotational force, the rotational vibration of the compressor occurring at high torque / high speed of the first compressor 50A and the second compressor 50B is transmitted along the right compressor vibration transmission direction (Y-axis direction of the xyz coordinate) and the left compressor vibration transmission direction (Y-axis direction of the xyz coordinate). In the right compressor vibration transmission direction, the vibration is transmitted from the first compressor 50A toward the right top plate, and in the left compressor vibration transmission direction, the vibration is transmitted from the second compressor 50B toward the left top plate.

[0108] Therefore, considering that the bending stiffness of the air conditioning unit 20 is greater in the width direction (the Y-axis direction of the xyz coordinates) than in the longitudinal direction (the X-axis direction of the xyz coordinates) due to its structure, the first compressor 50A and the second compressor 50B are arranged in the longitudinal direction (the X-axis direction of the xyz coordinates). As a result, the response characteristics of each of the first compressor 50A and the second compressor 50B are reduced.

[0109] However, first compressor 50A and second compressor 50B generate rotational vibrations at high torque and high rotational speed. This rotational vibration causes vibrations in air conditioning unit 20. However, due to the relatively small thickness of the roof frame and the internal connection parts of the vehicle body structure compared to the more rigid vehicle floor frame, roof panel 2 is inevitably susceptible to vibration isolation of air conditioning unit 20.

[0110] refer to Figure 10 Because the dual-isolation compressor mounting structure is connected to the air conditioning case connection member used for first compressor 50A and second compressor 50B, it can isolate the rotational vibration caused by the high torque and high rotation of first compressor 50A and second compressor 50B from the weak vibration isolation structure of air conditioning unit 20. This can suppress the transmission of vibration to vehicle interior 3.

[0111] As shown, the dual-insulated compressor mounting structure includes base members 55 and 56 , a compressor bracket 57 , a bushing 58 , and an insulator 59 .

[0112] For example, the base member is composed of a compressor mounting plate 55 and an air conditioner housing connecting rod 56. The compressor mounting plate 55 has a rectangular structure with dimensions matching the compressor. The air conditioner housing connecting rod 56 has a linear rod structure. In this example, the compressor mounting plate 55 is formed of a thickness and material that assists in vibration isolation by ensuring sufficient rigidity.

[0113] Two compressor mounting plates 55 are provided corresponding to the first compressor 50A and the second compressor 50B, and two air conditioning case connecting rods 56 are provided at the front and rear (X axis of xyz coordinates) of the compressor mounting plates 55 .

[0114] Thus, the compressor mounting plates 55 and the air conditioning case connecting rods 56 form a base structure for mounting the first compressor 50A and the second compressor 50B. The base structure is formed so that the air conditioning case connecting rods 56 are fixed to the left and right portions (in the Y-axis direction of the xyz coordinates) of the central mounting portion 31c in the case tray 31 of the air conditioning case 30, so as to match the front and rear ends of the compressor mounting plates 55. The two compressor mounting plates 55 are fastened to the air conditioning case connecting rods 56 in a parallel arrangement using bolts or screws.

[0115] For example, two compressor brackets 57 are provided and formed in an arch structure in which each of the first compressor 50A and the second compressor 50B forms a space with the compressor mounting plate 55 in a state of being fixed to the base structure by fastening with bolts or screws.

[0116] Specifically, compressor bracket 57 provides a two-stage bushing structure, with the compressor bushing application portion and the mounting plate bushing application portion being coupled to the mounting plate bushing application portion. Insulator 59 provides a dual insulation structure, with the compressor insulation application portion and the mounting plate insulation application portion being coupled to the mounting plate insulation application portion. In this example, bushing 58 and insulator 59 are each made of a rubber material.

[0117] Therefore, the compressor mount 57 may reduce vibration of each of the first compressor 50A and the second compressor 50B using a two-stage bushing for double insulation in which at least two bushings 58 and two insulators 59 are inserted.

[0118] As described above, the dual-inverter, dual-cycle roof-mounted air conditioning system 1-1 for an electric vehicle 1 according to an embodiment of the present disclosure can form a first refrigeration cycle 300A of a first compressor 50A and a first evaporator 70A with a built-in inverter 51, and a second refrigeration cycle 300B of a second compressor 50B and a second evaporator 70B with a built-in inverter 51 as independent bidirectional refrigerant paths, while a single condenser 60 is installed as a single-core condenser within the interior space of the air conditioning housing 30. This ensures the required cooling performance using a miniaturized dual compressor, and reduces the inverter capacity using a miniaturized dual-inverter power topology.

[0119] The present disclosure has been described with reference to exemplary embodiments and drawings, but the present disclosure is not limited thereto. Within the technical spirit of the present disclosure and the scope of equivalents of the appended claims, ordinary technicians in the field to which the present disclosure belongs can implement the present disclosure in various forms.

Claims

1. A dual-inverter dual-circulation roof-mounted air conditioning system for an electric vehicle, the air conditioning system comprising: A first compressor and a second compressor are arranged along the width direction of the vehicle; a condenser, arranged along the longitudinal direction of the vehicle; as well as The first evaporator and the second evaporator are arranged on the left and right sides of the condenser, The first refrigeration cycle including the first compressor and the first evaporator and the second refrigeration cycle including the second compressor and the second evaporator each have independent refrigerant paths in both left and right directions.

2. The air conditioning system according to claim 1, wherein: The condenser is a single core, and wherein an area of ​​the single core is divided to be used by the first refrigeration cycle and the second refrigeration cycle.

3. The air conditioning system according to claim 1, wherein: Each of the first compressor and the second compressor has an inverter built in.

4. The air conditioning system according to claim 1, wherein: A converter for driving a motor in the air conditioning system is disposed so that the first compressor and the second compressor are located between the converter and the condenser.

5. The air conditioning system according to claim 4, wherein: The converter is installed to be spaced apart from a bottom surface of the air conditioning system by a predetermined distance in an upward direction.

6. The air conditioning system according to claim 4, wherein: A condensing fan located above the condenser forms an air flow from the front side or the rear side of the air conditioning system along the converter, the first compressor, the second compressor, and the condenser.

7. The air conditioning system according to claim 4, wherein: A condensing fan located above the condenser forms airflow from the left and right sides of the air conditioning system along the first compressor, the second compressor, and the condenser.

8. The air conditioning system according to claim 4, wherein: The converter is connected to a motor of a first blower installed in an installation space of the first evaporator and a motor of a second blower installed in an installation space of the second evaporator.

9. The air conditioning system according to claim 4, further comprising: an air-conditioning housing in which each of the converter, the first compressor, the second compressor, and the condenser is mounted, The air conditioning housing forms a heat dissipation area in which surrounding spaces of the converter, the first compressor, the second compressor, and the condenser exchange heat with external air.

10. The air conditioning system according to claim 9, wherein: The air conditioning housing forms a structure in which the bottom of the air conditioning housing is inclined upward; and The bottom-up tilted structure of the air-conditioning housing is spaced apart from the upper surface of the vehicle body roof by forming a bottom-up tilted angle toward the center of the air-conditioning housing relative to the upper surface of the vehicle body roof.

11. The air conditioning system according to claim 9, wherein: The air conditioner case mounts a converter mounting bracket on a case bottom, wherein the converter mounting bracket positions the converter at an upper height matching a roof panel of a vehicle body roof.

12. The air conditioning system according to claim 9, wherein: The air conditioning housing forms a dual-insulated compressor installation structure in the installation space of the first compressor and the second compressor; and The dual-isolation compressor installation structure includes: a base member installed on the bottom of the air conditioner case to provide a mounting space for each of the first compressor and the second compressor, and A compressor bracket fixes the first compressor and the second compressor to the base member, respectively.

13. The air conditioning system according to claim 12, wherein: The base member comprises: a compressor mounting plate, the first compressor and the second compressor being located on the compressor mounting plate; and An air conditioning housing connecting rod is fixed to the bottom of the air conditioning housing to support the compressor mounting plate.

14. The air conditioning system according to claim 12, wherein: The compressor bracket has an arched structure, two bushings and two insulating members are inserted into the arched structure, and the compressor bracket and the compressor mounting plate form a separation space.

15. The air conditioning system according to claim 14, wherein: Each of the two bushings and the two insulators reduces compressor response characteristics of compressor rotation vibration generated when the first compressor and the second compressor are driven.

Images