EA044451B1 - COMPRESSED AIR PRODUCTION AND AIR CONDITIONING SYSTEM FOR RAILWAY VEHICLES - Google Patents

Description

Field of technology

This invention relates generally to the field of air conditioning systems and compressed air generation for railway vehicles.

State of the art

Modern trains for passenger rail transport are formed from permanent units. The expression constant composition indicates that the vehicle configuration is specified at the design stage, when the composition determines which vehicles will be traction-powered and which vehicles will be towed. Once a train is manufactured and assembled, it is broken down into individual vehicles only in the event of maintenance due to severe structural damage associated with one of the vehicles composing said train.

In fig. 1 depicts a non-limiting example of a stationary train 100 consisting of five cars 101, ..., 105.

According to the prior art, each vehicle included in the train 100 is equipped with a local HVAC system (heating, ventilation, air conditioning system), i.e. a system designed to provide heating, ventilation and air conditioning in the passenger compartment.

It is also known that in the railway passenger transport system, the braking systems use compressed air, suitably injected into the brake cylinders to generate braking force. Compressed air is produced by one or more compressors. For this purpose, compressors with different air flow rates can be used. Typically two compressors 121, 124 are installed, as shown by way of non-limiting example in FIG. 1. Determination of the flow rate depends on the requirements for the filling rate of the empty system when the train is started daily, as well as on backup parameters in the event of failure of at least one of the installed compressors.

It is known that each of the HVAC systems 111, ..., 115 are built into self-contained structures, usually installed on the roof of the train. In fig. Figure 3 shows a real example of a 1:1 scale HVAC system for regional trains.

In fig. 2, it is shown that within the HVAC system, in addition to various other devices, is a compressor 201 used to compress refrigerant gas, said refrigerant gas being exchanged to another portion 202 of the HVAC system. The compressor 201 is mechanically coupled to the engine 203 by a shaft 204. A mechanical coupling, not shown in the drawing, may be located between the engine 203 and the compressor 201 to compensate for misalignment of the two resulting half shafts. The electronic unit 205 receives electrical signals 207 from sensors forming part of the HVAC system 202 and electrical signals 208 from the passenger compartments to be air-conditioned. The electronic unit 205 controls the power supply device 206. The power supply device 206 collects electrical energy 209 distributed on board the vehicle and supplies power to the engine 203. The device 206 may be a simple remote control switch or a power frequency control device to control the engine 203 according to speed control parameters. The reproducible power value for motor 203 is in the order of 10 kVA.

An HVAC system similar in size to the system shown in FIG. 3, usually weighs about 500 kg.

It is known that each of the AGTU systems 121, 124 (air generation and treatment systems) is built into self-contained structures, usually mounted on the roof of the respective vehicle or suspended under its body. In fig. Figure 5 shows a real 1:1 scale example of an AGTU system for passenger vehicles.

In fig. 4 shows that within the AGTU system, in addition to various other devices, there is a compressor 401 used for compressing air. The compressed air is directed to the dryer 402 and subsequently accumulated in the main reservoir 403, from which it is then distributed to the consumers through the main brake line 404.

The compressor 401 is mechanically coupled to the engine 405 by means of a resilient coupling 406. The resilient coupling 406 is used to compensate for misalignment of the two resulting half shafts. The adjustable hysteresis pressure switch 407 turns on the power supply device 408 at a minimum pressure value of, by way of non-limiting example, 7 to 8 bar. The pressure switch 407 turns off the power supply device 408 at a maximum pressure value of, by way of non-limiting example, 9 to 10 bar. The power supply device 408 may be a remote controlled switch or, less commonly, a power frequency control device that controls the motor 405 according to speed control parameters, known as soft starting.

The typical power to flow ratio for a 405 motor is about 1 kVA at

- 1 044451 flow rate 100 l/min. In a specific case, such as the passenger train shown in FIG. 1, for each AGTU system 121, 124 a flow rate of 800 to 1200 l/min is required, i.e. Each 405 motor should be approximately 8 to 12 kVA.

An AGTU system similar in size to the system shown in FIG. 5, has a weight of about 500 kg. The weight of the corresponding 405 engine is approximately 70 kg. The weight of the support frame for the entire AGTU system can range from 70 to 150 kg.

To reduce sources of contamination such as lubricating oils inside compressors, a technology known as oil-free is now preferred. The oil-free solution further improves a metric called life cycle cost (LCC), i.e. costs over the full life of the compressor as it eliminates the periodic maintenance cycles required to change lubricating oil.

When using oil-free technologies, the above air flow rates can be achieved exclusively using reciprocating compressors, characterized by high acoustic noise and strong vibrations generated by the supporting structures or vehicle carriages to which said structures are attached.

There are oil-free alternatives to reciprocating compressors, known as scroll compressors, which are rotary-only and do not produce acoustic noise or harmful mechanical vibrations. However, such scroll compressors do not provide high flow rates of the order of 500 l/min. If you intend to use scroll compressors, it is necessary to install a large number of components, which is associated with additional costs for motors and support frames for AGTU and leads to an increase in weight and the required space for their installation.

The essence of the invention

The purpose of this invention is to provide a solution that allows the integration of AGTU systems and HVAC systems forming part of at least one railway vehicle or several railway vehicles of one railway train.

Another object is to provide a solution that reduces the number of motors required to generate compressed air and air conditioning in at least one railway vehicle or several railway vehicles of one railway train.

The above and other objects and advantages are achieved according to an aspect of the invention using a system for generating compressed air and air conditioning, which has the features set forth in claim 1 of the claims. Preferred embodiments of the invention are described in the dependent claims, the contents of which should be considered an integral part of this description.

Brief description of the figures

Below is a description of the functional and design features of some preferred embodiments of an electronic emergency and service braking control system made according to the invention. Reference is made to the accompanying drawings, in which:

fig. 1 depicts a non-limiting example of a permanent train consisting of five cars;

fig. 2 shows the internal structure of an HVAC system;

fig. 3 depicts a real example of an HVAC system for vehicles used for passenger transport;

fig. 4 shows the internal structure of the AGTU system;

fig. 5 shows an example of an AGTU system for vehicles used for passenger transport;

fig. 6 shows a system for generating compressed air and air conditioning according to the invention; and figs. 7 depicts a non-limiting example of a fixed five-car train using the solution shown in FIG. 5.

Detailed description

Before proceeding to a detailed description of embodiments of the invention, it should be clarified that the invention is not limited in its application to the structural elements and configuration of components presented in the following description or depicted in the drawings. The invention may have other embodiments and may be carried out or practiced in various ways. It should also be understood that the phraseology and terminology used are for descriptive purposes and should not be construed as limiting. It should be understood that as used herein, the words include and contain and their derivatives include the elements listed thereafter and their equivalents, as well as additional elements and their equivalents.

This patent relates to a solution for combining AGTU systems and HVAC systems forming part of the same train.

In fig. 6 shows a system for generating compressed air and air conditioning, you

- 2 044451 complete according to the invention.

In particular, the single electric motor 601 may be selectively coupled to the first compressor 602 providing compressed air via the first connecting means 603.

The first compressor 602 is designed to compress intake air at atmospheric pressure. The air is directed to a dryer 615 and then accumulated in a main reservoir 616, from which it is subsequently distributed to various loads via a main brake line 617. By way of non-limiting example, loads may include a train braking system.

The single motor 601 may also be selectively coupled to the second compressor 608 via a second coupling means 609.

A second compressor 608 is connected to the HVAC system 111, ..., 115.

The second compressor 208 is designed to compress the refrigerant gas, which is exchanged to the rest of the HVAC system 620.

Thus, system 600 includes one electric motor 601 configured to provide mechanical torque selectively to first compressor 602 and/or second compressor 608.

The mechanical torque is selectively applied to the first compressor 602 and/or the second compressor 608 as a function of a first electrical signal 619 generated by a pressure sensing device 618 indicating the pressure in the main brake line 617 or the main reservoir 616 and at least one second electrical signal 621 , coming from the air conditioning system 620 and indicating a temperature or pressure or humidity value, and at least one third electrical signal 622 indicating the temperature of the environment to be conditioned in the railway vehicle.

The system may include an electronic control unit 607 configured to generate a first control signal 606 for the first coupling means 603 for connecting or disconnecting the electric motor 601 and the first compressor 602, and a second control signal 612 for the second connecting means 609 for connecting or disconnecting the electric motor 601 and a second compressor 608.

The first connection means 603 and the second connection means 609 may be respective electromagnetic assemblies.

In this case, the first connecting means 603, i.e. the electromagnetic assembly connects/disconnects the first axle shaft 604 associated with the first compressor 602 and the second axle shaft 605 associated with the electric motor 601 depending on the first electrical signal 606 generated by the electronic control unit 607.

When the first coupling means 603 causes the first and second axle shafts 604, 605 to be connected, the electric motor 601 transmits mechanical torque to the first compressor 602. On the other hand, when the first coupling means 603 causes the first axle shaft 604 and the second axle shaft 605 to be separated, the first compressor 602 does not receive mechanical torque from the 601 electric motor.

The second connecting means 609, i.e. the electromechanical assembly provides connection/disconnection of the third axle shaft 610 and the fourth axle shaft 611 depending on the second electrical signal 612 generated by the electronic control unit 607. A third axle shaft 610 is coupled to an electric motor 601, and a fourth axle shaft 611 is coupled to a second compressor 608.

When the second coupling means 609 couples the second axle shaft 610 and the third axle shaft 611, the electric motor 601 transmits mechanical torque to the second compressor 608. On the other hand, when the second coupling means 609 disengages the third axle shaft 610 and the fourth axle shaft 611, the second compressor 608 does not receive mechanical torque from the 601 electric motor.

For example, but without limitation, each of the electromechanical assembly of the first coupling means 603 and the electromechanical assembly of the second coupling means 609 may be an electromagnetic clutch.

According to FIG. 5, the electronic control unit 607 receives the first electrical signal 619 generated by the pressure measuring device 618.

For example, but not limited to, pressure measuring device 618 may be a pressure switch with adjustable hysteresis. In this case, the first electrical signal 619 may indicate the need to turn on the first compressor 602 and, therefore, the need to apply mechanical torque generated by the electric motor to the first compressor 602 when the signal 619 indicates that the pressure in the main brake line 617, measured with using device 618, reaches a minimum pressure of, by way of non-limiting example, 7 to 8 bar.

In another, non-limiting example, pressure measuring device 618

- 3 044451 may be a pressure sensor generating a first electrical signal 619 proportional to the pressure value measured in the main brake line 617. In this case, the first electrical signal 619 may indicate the need to shut down the first compressor 602, and therefore does not indicate the need to supplying the mechanical torque generated by the electric motor to the first compressor 602 when the pressure in the main brake line 617 measured by the device 618 reaches a maximum value, by way of non-limiting example being 9 to 10 bar.

In addition, the electronic control unit 607 also receives said at least one second electrical signal 621 from said at least one sensor included in the HVAC system 620 and said at least one third electrical signal 622 from said at least one sensor. at least one temperature sensor located in the passenger compartment of the train, subject to air conditioning. It will be appreciated that the second electrical signals 621 may be a set of signals and come from multiple sensors, each of which is designed to measure pressure, temperature or humidity with respect to the HVAC system 620, and the third electrical signals 622 may be a set of signals and come from multiple sensors temperatures located in different passenger compartments of a railway vehicle subject to air conditioning.

The electronic control unit 607 may control a power supply device 613 for receiving power 614 distributed throughout the railroad vehicle and supplying power to the motor 601.

For example, the power supply device 613 may be a simple remote controlled switch or a power frequency control device, also technically referred to as an inverter, for controlling the electric motor 601 according to speed control parameters.

The electronic control unit 607 may cause the power supply device 613, and therefore the electric motor 601, to be driven if the first electrical signal 619 indicates the need to turn on the first compressor 602 or if at least one of the second electrical signal 621 and the third electrical signal 622 indicates the need to turn on the second compressor 608 and therefore indicates the need to supply the mechanical torque generated by the electric motor to the second compressor 608.

If the corresponding compressors 602, 608 are not simultaneously requested to be activated in accordance with the first electrical signal 619, as well as the second electrical signal 621 and the third electrical signal 622, the electronic control unit 607 turns off the power supply device 613, turning off the electric motor 601.

To summarize the above, the electronic control unit 607 continuously analyzes the first electrical signal 619, as well as the second electrical signal 621 and the third electrical signal 622, and decides when to operate the power supply device 613 and therefore the motor 601 and which one of the first connecting means 603 and the second connecting means 609 are activated to supply the corresponding mechanical torque generated by the electric motor to the first compressor 602 and/or the second compressor 608, respectively.

In one possible embodiment, the electric motor 601 is configured to supply a mechanical torque equivalent to the sum of the maximum mechanical torques of the first and second compressors 602, 608 so that they can be driven simultaneously.

In this embodiment, the electronic control unit 607 actuates the first connecting means 603 if the first electrical signal 619 indicates the need to turn on the first compressor 602, and actuates the second connecting means 609 if at least one of the second electrical signal 621 and the third electrical signal 622 indicates the need to turn on the second compressor 608. When there is a simultaneous request from the first electrical signal 619 and from the second electrical signal 621 or the third electrical signal 622 to turn on the respective compressors 602, 608, the electronic control unit 607 simultaneously operates both the first connecting means 603 and second connecting means 609 for providing connection of the electric motor 601 to both the first compressor 602 and the second compressor 608.

The electronic control unit 607 disables the first connecting means 603 when the first electrical signal 619 indicates that the maximum pressure value has been reached in the main tank 616, that is, does not indicate the need for mechanical torque generated by the electric motor to be supplied to the first compressor 602, or disables the second connecting means. means 609 if at least one of the second electrical signal 621 and the third electrical signal 622 indicates that compression of the refrigerant gas is not required, that is, does not indicate the need to supply mechanical torque generated by the electric motor to the second compressor 608.

In another possible embodiment, the electric motor 601 is configured to create

- 4 044451 torque being the greater of the maximum mechanical torque of the first compressor 602 and the maximum mechanical torque of the second compressor 608.

In this further embodiment, because the electric motor 601 can only supply the greater of the mechanical torques of the two compressors 602, 608, in the event of simultaneous requests to turn on the electric motor 601 from the first electrical signal 619 and at least one of the second electrical signal 621 and the third electrical signal 622, block 607 alternately operates the first coupling means 603 and the second coupling means 609 in accordance with algorithms preloaded, for example, into non-volatile memory 624 in the form of executable code or operating parameters to alternately connect the electric motor 601 to the first compressor 602 and to the second compressor 608.

For example, but without limitation, the first algorithm is to give absolute priority to the mechanical torque request for the first compressor 602 from the first electrical signal 619 as it is typically associated with a pressure request from the brake system.

When there is a request for mechanical torque from the first electrical signal 619, the electronic control unit 607 performs the following actions:

turns on the power supply device 613 if it is not already activated;

disables the second connecting means 609 if it has already been activated as a result of a valid request from at least one of the second electrical signal 621 and the third electrical signal 622;

turns on the first connecting means 603, keeping it turned on until the pressure in the main reservoir 616 reaches a predetermined maximum value.

When the pressure in the main reservoir 616 reaches a predetermined maximum value, the electronic control unit 607 performs the following actions:

disconnects the first connecting means 603;

includes second connecting means 609 if there is a valid request from at least one of the second electrical signal 621 and the third electrical signal 622;

disables or leaves disconnected the second mechanical connecting means 609 and disables the power supply device 613 if the request from the second electrical signal 621 and the third electrical signal 622 is not satisfied or absent.

If, during the turn-on step of the second connecting means 609, the request from the first electrical signal 619 occurs again, the cycle begins again.

As a non-limiting example, the second algorithm is to give temporal priority to the activation request coming from the first electrical signal 619 as it is typically associated with a pressure request from the brake system. This second algorithm requires the pressure measuring device 618 to include a linear pressure sensor capable of providing a continuous pressure value signal as the first electrical signal 619.

When there is a request for mechanical torque from the first electrical signal 619, the electronic control unit 607 performs the following actions:

turns on the power supply device 613 if it is not already activated;

disables the second connecting means 609 if it has already been activated as a result of a valid request from at least one of the second electrical signal 621 and the third electrical signal 622;

turns on the first connecting means 603, maintaining it on until the pressure in the main reservoir 616 reaches a first intermediate value between a minimum value and a predetermined maximum value, the first pressure value being sufficient to ensure, by way of non-limiting example, at least one emergency braking, upon reaching the specified first intermediate value, turns off the first connecting means 603 and turns on the second connecting means 609;

disables the second coupling means 609 and re-enables the first coupling means 603 when the second electrical signal 621 and the third electrical signal 622 indicate that the mechanical torque request for the second compressor 608 is no longer supplied;

disconnects the first connecting means 603 and turns off the power supply device 613 when the first electrical signal 619 indicates that a predetermined maximum pressure value has been reached.

During the described sequence of actions, any return of the first electrical signal 619 to a value indicating the minimum pressure in the main reservoir 616 again starts the specified sequence from the beginning.

The first and second compressors 602 and 608 may be positive displacement compressors. It is well known that the required mechanical torque for a positive displacement compressor can be considered

- 5 044451 proportional to the compressor outlet pressure, unless the torque applied is necessary to overcome friction in said compressor.

Based on the foregoing, it can be stated that when the pressure in the main reservoir 616 corresponds to a predetermined minimum value, the required torque for the first compressor 602 is less than the torque required for the specified compressor 602 when the pressure in the main reservoir 616 reaches a predetermined maximum value. A similar estimate can be made for the second compressor 608. Therefore, if both the first and second compressors 602, 608 are at their respective minimum operating pressures, the sum of the mechanical torques required to drive said compressors may be less than the maximum torque, which may be provided by the electric motor 601.

It is known that the inverter device, which is part of or forms a power supply device 613, is capable of controlling currents supplied to the electric motor 601, determining the instantaneous value of these currents, and continuously transmitting information about the specified instantaneous value of these currents to the electronic control unit 607.

As a non-limiting example, if the power supply device 613 contains or consists of an inverter, then when there is a simultaneous request to supply mechanical torque to the respective compressors 602, 608 from the first electrical signal 619 and at least one of the second electrical signal 621 and a third electrical signal 622, the third algorithm causes the first connecting means 603 and the second connecting means 609 to be simultaneously driven by a block 607 to connect the electric motor 601 to both the first compressor 602 and the second compressor 608, as long as the current supplied by the inverter 613 will not reach the maximum value that can be provided by said inverter 613.

When the inverter reaches its maximum supplied current as a result of the gradual increase in pressures downstream of the first and second compressors 602, 608, the electronic control unit 607 may then select the first or second course of action described above.

In fig. 1 shows a non-limiting example of a stationary train 100 consisting of five cars 101, ..., 105, each of which is equipped with an on-site HVAC system 111, ..., 115. Train 100 is also equipped with two on-site AGTU systems 121, 124. When choosing a solution according to With this invention, train 100 would take the form 700 shown in FIG. 7, where each car 701, ..., 705 contains its own system 711, ..., 715 for generating compressed air and air conditioning.

In this case, the air flow supplied by the two compressors included in the AGTU systems 121, 124 is divided between different systems 711, ..., 715 for generating compressed air and air conditioning.

The advantage of this new configuration shown in FIG. 7 is the absence of AGTU systems 121, 124, which reduces the weight of the train 700 and increases the available space for installing other systems that would otherwise be installed in the car.

In addition, distributing the flow from a limited number of AGTU systems 121, 124 to a larger number of compressed air generation and air conditioning systems 711, ..., 715 provides the ability to reduce flow rates for the compressors included in said systems 711, ..., 715. ., 715 (as a non-limiting example, in relation to Figs. 1 and 7 - at a ratio of 2:5). This reduction in flow allows a successful transition, for example, from non-lubricated piston compressors to non-lubricated scroll compressors, which reduces the generated acoustic noise and mechanical vibrations caused by the compressors in the respective cars.

The system shown in FIG. 6 may have a connection to an on-board communications system 623 providing connection to at least two of a set of compressed air generation (AGTU) and air conditioning (HVAC) systems 711, ..., 715 located on board the train 700. It should be noted that that the main brake line 617 and the main reservoir 616 are the same for the entire train 700, and also common to all systems 711, ..., 715.

In this case, the algorithm for assigning the torque provided by the electric motors 601 to the first and second compressors 602, 608 of each system 711, ..., 715 may be based on distributed control.

The first of the compressed air generation and air conditioning systems 711, ..., 715, which faces a simultaneous request from its electrical signals 619 and 621, 622 for mechanical torque to its first and second compressors 602, 608, before giving priority request coming from the first electrical signal 619, as described above in the first, second and third algorithms, by exchanging information through the communication means 623, verifies that at least one other system 711, ..., 715 has requested mechanical torque for its second compressor 608 by at least one of its second electrical signal 621 and third electrical signal 622. In this case, the first compressed air generation and air conditioning system gives priority to the mechanical torque request for its first compressor 608 coming from at least one of its second electrical signal 621 and

-

Claims (6)

third electrical signal 622. If there is a communication means 623 that allows the electronic control units 607 of two or more systems 711,..., 715 to communicate with each other, other distributed action algorithms similar to the algorithms described above can be created, while priority is always given to the request for submission to main tank 616 when the pressure value inside said tank has reached a minimum value. The above is a description of various aspects and embodiments of a system for generating compressed air and air conditioning according to the invention. It should be understood that each embodiment may be combined with any other embodiment. In addition, the invention is not limited to the described embodiments, but can be modified within the scope defined by the attached claims. CLAIM 1. A system (600) for generating compressed air and air conditioning, intended for at least one railway vehicle (701, ..., 705) and containing a first compressor (602) configured to generate compressed air for supply to the main a reservoir (616) and a main brake line (617) of a railway vehicle through an air drying unit (615), and a second compressor (608) configured to compress gaseous refrigerant for an air conditioning system (620) of said at least one railway vehicle , wherein said system (600) is characterized in that it comprises a single electric motor (601) configured to generate a mechanical torque selectively supplied to the first compressor (602), or to the second compressor (608), or simultaneously to both the first compressor (602), and to the second compressor (608), depending on: a first electrical signal (619) generated by a pressure measuring device (618) indicating pressure in the main brake line (617) or in the main reservoir (616); and at least one second electrical signal (621) coming from the air conditioning system (620) and indicating a value of temperature or pressure or humidity, and at least one third electrical signal (622) indicating the temperature of the environment to be conditioned in the railway vehicle. 2. The system (600) according to claim 1, comprising an electronic control unit (607) for controlling the system (600), wherein the electronic control unit (607) is configured to receive a first electrical signal (619) of said at least one a second electrical signal (621) and said at least one third electrical signal (622); the electronic control unit (607) is configured to operate a power supply device (613) deriving energy from an electrical power source (614) to power said single electric motor (601) when the first electrical signal (619) indicates the need to apply mechanical torque torque to the first compressor (602) or if at least one of the second electrical signal (621) and the third electrical signal (622) indicates the need to apply mechanical torque to the second compressor (608), wherein the electronic control unit (607) is configured with the ability to generate: a first control signal (606) for a first connecting means (603) for connecting or disconnecting the electric motor (601) and the first compressor (602); a second control signal (612) for a second connecting means (609) for connecting or disconnecting the electric motor (601) and the second compressor (608). 3. System (600) according to claim 1 or 2, in which the electronic unit (607) contains non-volatile memory (624) for preventive storage of control algorithms of the specified system (600). 4. System (600) according to claim 2 or 3, in which each of the first and second compressors (602, 608) is provided with its own maximum mechanical torque, and the electric motor (601) is configured to provide a mechanical torque equal to the sum of the maximum mechanical torques required for the first and second compressors (602, 608), or greater than a specified amount, wherein only the first electrical signal (619) from the pressure sensing device (618) indicates the need for mechanical torque for the first compressor (602), the electronic control unit (607) is configured to influence the first connecting means (603) and the second connecting means (609) of the specified system (600) to ensure that the mechanical torque generated by the electric motor is supplied only to the first compressor (602), wherein when only at least one of the second electrical signal (621) and the third - 7 044451 electrical signal (622) indicates the need for mechanical torque for the second compressor (608), the electronic unit (607) is configured to influence the first connecting means (603) and the second connecting means (609) to provide mechanical torque generated by the electric motor, only to the second compressor (608); when simultaneously a first electrical signal (619) from a pressure sensing device (618) indicates a mechanical torque requirement for the first compressor (602) and at least one of a second electrical signal (621) and a third electrical signal (622 ) indicates the need for mechanical torque for the second compressor (608), the electronic unit (607) is configured to act on the first connecting means (603) and on the second connecting means (609) to provide simultaneous supply of mechanical torque generated by the electric motor, to the first compressor (602) and to the second compressor (608). 5. The system (600) according to claim 2 or 3, wherein each of the first and second compressors (602, 608) is provided with its own maximum mechanical torque, and the electric motor (601) is configured to provide a mechanical torque of at least equal to the greater of the maximum mechanical torques required for the first and second compressors (602, 608), wherein only the first electrical signal (619) from the pressure sensing device (618) indicates the need for mechanical torque for the first compressor (602), the electronic unit (607) is configured to act on the first connecting means (603) and on the second connecting means (609) to ensure that the mechanical torque generated by the electric motor is supplied only to the first compressor (602), wherein, when only at least one of the second electrical signal (621) and the third electrical signal (622) from the air conditioning system (620) or the environment to be conditioned indicates a need for mechanical torque for the second compressor (608), electronic the block is configured to act on the first connecting means (603) and on the second connecting means (609) to ensure that the mechanical torque generated by the electric motor is supplied only to the second compressor (608); when simultaneously a first electrical signal (619) from a pressure sensing device (618) indicates a mechanical torque requirement for the first compressor (602) and at least one of a second electrical signal (621) and a third electrical signal (622 ) coming from the air conditioning system (620) or from the environment to be conditioned, indicates the need for mechanical torque for the second compressor (608), the electronic unit (607) is configured to act on the first connecting means (603) and on the second connecting means means (609) for causing the mechanical torque generated by the electric motor to be supplied only to the first compressor (602). 6. System (600) according to any one of claims 2-4, in which each of the first and second compressors (602, 608) is provided with its own maximum mechanical torque, and the electric motor (601) is configured to provide mechanical torque, according to at least equal to the greater of the maximum mechanical torques required for the first and second compressors (602, 608), wherein only the first electrical signal (619) from the pressure sensing device (618) indicates the need for mechanical torque moment for the first compressor (602), the electronic unit (607) is configured to act on the first connecting means (603) and on the second connecting means (609) to ensure that the mechanical torque generated by the electric motor is supplied only to the first compressor (602), wherein only at least one of the second electrical signal (621) and the third electrical signal (622) from the air conditioning system (620) or the environment to be conditioned indicates a need for mechanical torque for the second compressor (608) , the electronic unit (607) is configured to act on the first connecting means (603) and on the second connecting means (609) to provide mechanical torque generated by the electric motor to only the second compressor (608); when simultaneously the first electrical signal (619) from the pressure measuring device (618) indicates that the pressure value in the main reservoir (616) is less than a predetermined intermediate value, and at least one of the second electrical signal (621) and a third electrical signal (622) from the air conditioning system (620) or the environment to be conditioned indicates a need for mechanical torque for the second compressor (608), the electronic unit (607) is configured to act on the first connecting means (603 ) and to the second connecting means (609) to ensure that the mechanical torque generated by the electric motor is supplied only to the first compressor (602); when simultaneously the first electrical signal (619) coming from the device (618) for -