EP3368359A2

EP3368359A2 - Electrical powered unit to power a ground vehicle

Info

Publication number: EP3368359A2
Application number: EP16825881.2A
Authority: EP
Inventors: Ezio Bertotto; Roberto LOTTO
Original assignee: D&M Holding SpA
Current assignee: Enerdrive Ltd
Priority date: 2015-10-28
Filing date: 2016-10-28
Publication date: 2018-09-05
Also published as: ITUB201586605U1; WO2017072724A2; CN108367659A; WO2017072724A3

Abstract

A propulsion unit for a land vehicle (V, T), comprises at least one electric drive unit (2) operatively associable with at least one wheel and/or at least one pair of idle semi-axles (S2) and/or at least one idle axle (S2') of the land vehicle (V, T), wherein at least one wheel and/or at least one pair of idle semi-axles (S2) and/or at least one idle axle (S2') are/is of the driven type, one electric power source (B) of the at least one electrical drive unit (2), the latter comprising at least one synchronous reluctance motor (3) of the type assisted by permanent magnets.

Description

"ELECTRICAL POWERED UNIT TO POWER A GROUND VEHICLE'

TECHNICAL FIELD OF THE INVENTION

The present invention relates to an electrical powered unit to supply power for the propulsion of a land vehicle.

More particularly, the present invention relates to a propulsion unit comprising at least one electric drive unit operatively associable with at least one wheel or at least one idle or auxiliary axle of a land vehicle, to allow the propulsion of the same.

STATE OF THE ART

In land vehicles with so-called hybrid drive, the combined operation of an endothermic drive unit and an electric drive unit is provided. The electric drive unit can temporarily enslave the endothermic unit or, under certain conditions, act itself as the exclusive motion source for the movement of the land vehicle.

During some phases that represent the critical conditions of functionality for land vehicles, such as starting from a standstill or in the case of repeated stops/starts, the propulsion can be assigned exclusively to the electric drive unit, thus allowing a considerable reduction in the fuel consumption.

Conventional electric drive units have operational limitations, with particular reference to the speed range within which such electric drive units are capable of delivering optimal torque values. More specifically, it is noted that conventional electric drive units are not able to guarantee satisfactory torque values at low rates of rotation- and, at the same time, good torque values at high rates of rotation. Consequently, the use of electric drive units, known to be a source of motion for a vehicle, is limited to a reduced speed range with respect to that of the operation of the vehicle on which they are installed.

In order to overcome this drawback, a mechanical gearbox can be provided to associate with the transmission which connects the electric drive unit to the axle to be operated in rotation. This solution, however, entails a greater structural complexity, such to the point that, in some cases, is not implementable in a land vehicle.

Today, the problem of pollutant emissions from land vehicles is of greater importance than in the past, to the point that, increasingly, there is the requirement for propulsion systems of land vehicles which promote a substantial reduction of these emissions, even in the scope of a solution able to ensure good performance in terms of deliverable torque, velocity and acceleration.

OBJECTS OF THE INVENTION

The main object thus of this invention is to improve the state of the art relative to an electric powered supply unit for the propulsion of at least one wheel or at least one axle or of at least one pair of semi-axles associated with each other on a land vehicle.

Within this aim, an object of the present invention is to provide a unit for the propulsion of at least one wheel or at least one axle or of at least one pair of semi- axles associated with each other, on a land vehicle, in order to ensure high performance in terms of torque that is deliverable substantially for the entire operation speed range of such land vehicle.

Another object of the present invention is to provide a unit for the propulsion of at least one wheel or at least one axle or of at least one pair of semi-axles associated with each other on a land vehicle that can be easily implemented in existing land vehicles.

According to one aspect of the present invention it provides a unit for the propulsion of at least one wheel and/or at least one axle and/or a pair of semi- axles associated with each other on a land vehicle according to claim 1.

The dependent claims refer to preferred and advantageous embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present invention will become more apparent from the detailed description of a preferred, non-exclusive embodiment, of a unit for the propulsion of at least one wheel and/or of at least one axle and/or of at least one pair of semi-axles associated with each other on a land vehicle, illustrated by way of an indicative, but not limitative, example in the accompanying drawings, wherein:

Figure 1 is a block diagram of one embodiment of a propulsion unit according to the present invention;

Figure 2 is a block diagram of a further version of a propulsion unit according to

Figure 1;

Figure 3 is a schematic view of some components of a propulsion unit according to the present invention;

Figure 4 is an exploded view of a possible embodiment of the propulsion unit according to the present invention;

Figure 5 is an exploded view of a further embodiment of the propulsion unit according to the present invention;

Figure 6 is a perspective view of a land vehicle provided with a propulsion unit according to the present invention;

Figure 7 is a schematic graph of the torque and power characteristic curves of a propulsion unit according to the present invention;

Figure 8 is a comparison chart between the characteristic curves of the torque deliverable by a propulsion unit according to the present invention, respectively in a first or in a second operating configuration.

EMBODIMENTS OF THE INVENTION

With reference to the attached figures, a unit for the propulsion of at least one wheel and/or of at least one axle and/or of at least one pair of semi-axles associated or associable with each other of a land vehicle it is generally indicated by reference number 1.

It is intended that the propulsion unit, according to the present invention, can optionally be used for the propulsion of all the wheels and/or of all axles and/or semi-axis of a land vehicle, without limitation.

The term land vehicle means any vehicle whose movement occurs on the ground and comprises at least one pair of wheels or a pair of axles or semi-axles which are associated with the respective wheels. By way of example, but not limitation, a land vehicle can be configured as a coach or train, a tram, a trailer, a car, a motorcycle, a three-wheeler, etc., without limitation.

More specifically, it is observed that the propulsion unit, according to the present invention, is provided to be associated with at least one idle wheel and/or at least one idle axle and/or to a pair of idle semi-axles coupled together and/or to at least one pair of wheel hubs, coupled together, of a land vehicle, without limitation. In particular, the term "idle or auxiliary" is meant to indicate a mechanical conduit or, normally non-motorised, element.

In the accompanying figures reference will be made to a land vehicle V, such as a car (Figures 1 and 2) or articulated vehicle (Figure 6), comprising a drive unit M of the endothermic type.

The technician of this field can easily understand how the propulsion unit 1 can enslave any land vehicle V.

According to one version of the present invention, not illustrated in the attached figures, the propulsion unit 1 can enslave an electric propulsion land vehicle V which, for example, the drive of a train, a tram, an electric car or the like, without any limitation, to support or in place of the driving source therein provided.

The propulsion unit 1 may also be found useful in the propulsion of at least one wheel of a motorcycle, a three-wheeler or the like, without any limitation to the objects of the present invention.

The following will describe briefly some elements of a land vehicle V configured as a motor vehicle comprising an internal combustion engine M. It is understood that the type of land vehicle V to which the propulsion unit 1 is associable can vary with respect to what is stated in the following, without departing from the scope of protection according to the present invention.

By way of example, but not limitative, with reference to the embodiment illustrated in Figure 1, a land vehicle V, such as a car, may comprise an internal combustion engine M operatively associated with transmission members G for the transmission of motion to the first motor-powered semi-axles S 1. The vehicle V may comprise at least one pair of idle semi-axles S2, coupled together, to which are associated respective wheels for the advancement of the vehicle V on a ground or the like.

The land vehicle V may include, among other elements, a system of accumulation/distribution of electrical energy B - a battery unit - a generator/alternator A associated with the internal combustion engine M, and at least one electronic control unit ECU or the like for the electronic management of the internal combustion engine M itself.

These elements, as well as their operation, are considered known and, therefore, will not be further described.

With reference to the embodiment illustrated in Figure 1, the propulsion unit 1 according to the present invention comprises at least one electric drive unit 2 operatively associable with at least one pair of idle semi-axles S2 of the land vehicle V and electric power supply means of the same.

According to one version of the present invention, the electric power supply means may correspond to the accumulation/distribution of electrical energy B installed in the land vehicle V.

According to a further version of the present invention, not illustrated in the attached figures, the electric power supply means may be of a type dedicated to the propulsion unit 1 and, as such, may be distinct from the electrical energy accumulation/distribution unit B installed in the land vehicle V.

At least one electrical drive unit 2 comprises at least one synchronous reluctance motor 3 of the type with permanent magnets (Figure 3).

The synchronous reluctance motor 3 can be operatively associated with at least one wheel or at least one pair of second idle semi-axles S2 to be operated in rotation, via a respective transmission 4.

The transmission 4 can be configured as any of a mechanical transmission, such as a mechanical gearbox, of the type adapted to get the rotary motion output from the synchronous reluctance motor 3 and to transmit it to at least one wheel or at least one pair of second semi-axles S2, in order to operate the same in rotation about a common axis of rotation 5.

According to one version of the present invention, the transmission 4 may comprise clutch members, not illustrated in the attached figures, adapted to reciprocally connect/disconnect, the synchronous reluctance motor 3 to/from at least one wheel or to/from at least one pair of second semi-axles S2, in function of specific requirements for the operation of the land vehicle V.

The synchronous permanent magnet motor 3 comprises a stator 6 provided with a central seat 7 inside which is placed a rotor 8, operable in rotation relative to the stator 6. As known, the rotor 8 and the stator 6 are mutually separated by means of a defined space 9 defined as "air gap".

At the inner peripheral portion of the statpr 6, which faces the rotor 8, there is a plurality of stator windings, wholly indicated with 10.

The synchronous reluctance motor 3 includes permanent magnets 11 positioned internally to the rotor 8.

More in detail, it is observed that the rotor 8 has a plurality of shaped recesses 12, within which respective permanent magnets 11 are accommodated (see Figure 3).

The number, the position and conformation of the shaped recesses 12 and of the permanent magnets 11 may vary with respect to what is illustrated in the attached

Figure 3, in function of specific operational requirements, without thereby departing from the scope of protection according to the present invention.

As is known, a synchronous reluctance motor 3 reaches a rated rotation speed when is supplied according to nominal voltage conditions.

The attached figure 7 illustrates a graph of the curves characteristics of torque C and of power P deliverable by an electric drive unit 2 according to the present invention, as a function of the rotation speed N of the engine itself.

In this chart, two distinct regions of the electrical drive unit 2 can be identified: a first region Cc, called constant torque, and a second region Pc, called constant power.

The first drive region Cc, in which the electric drive unit 2 operates according to a rate of constant torque speed, is between a rotation speed of substantially zero and a defined nominal speed Nn.

Within the first region drive Cc, the magnetic flux of the rotor 8 is maintained at a maximum value. In such operation conditions, the electric drive unit 2 may deliver a maximum torque value Cm for any rotation rate of the rotor 8 which is comprised in such speed range.

The second region drive Pc, in which the electric drive unit 2 operates in a rate of constant power, extends within a speed range comprised between the nominal speed Nn and the maximum speed Nm at which the electrical drive unit 2 can operate without undergo any damage.

Wishing to drive the electric drive unit 2 at rotation rates above the stated nominal speed, thereby actuating the rotor 8 of the at least one synchronous reluctance motor 3 at a speed higher than the nominal one Nn, it is necessary to operate according to so-called conditions of "weakening".

Through the weakening it is possible to increase the rotation speed of an electric motor beyond the stated nominal speed value Nn up to a value of maximum sustainable speed Nm for the electric motor itself, without undergo any damage.

In case of driving at a speed above the nominal Nn, the synchronous reluctance motor 3 operates according to constant power and current conditions, while the torque is inversely proportional to the value of the rotation speed.

The weakening, therefore, can be carried out in cases where high rotation rates are required for which are admissible torque values lower than that of the maximum torque Cm.

According to one version of the present invention, at least one electric drive unit 2, within a weakening rate, can operate up to a maximum rotation speed Nm equal to almost ten times the value of the nominal speed Nn.

The propulsion unit 1 may comprise control means 13 of at least one electric drive unit 2, and more precisely of the synchronous reluctance motor 3, for the management of the weakening of the latter.

Through the above mentioned control means 13 it is possible to extend the field of operational speed of a propulsion unit 1 according to the present invention, as better described hereinafter.

According to one aspect of the present invention, the control means 13 may comprise an inverter, not shown in detail in the accompanying figures, to manage the power supply of at least one electric drive unit 2.

The operation of an inverter is considered known and, therefore, will not be further described hereinafter.

According to one version of the present invention, the propulsion unit 1 is provided to be associated with at least one pair of second idle semi-axles S2 of a land vehicle V.

During normal operation of the land vehicle, at least one pair of second semi-axles S2, in use, can achieve a high rate of rotation.

In order, therefore, to extend the velocity rate for the optimal operation of the at least one synchronous reluctance motor 3, and to guarantee optimum torque values applied to the at least one pair of second semi-axles S2, the control means 13 of the propulsion unit 1 according to the present invention comprise means for switching, wholly indicated with 14, which are suitable to switch the connections of the stator windings 10 of the at least a synchronous reluctance motor 3 between a first operating configuration and a second operating configuration.

As better described hereinafter, the means for switching 14 allow to further expand the velocity range within which the at least one synchronous reluctance motor 3 can operate efficiently, and deliver optimal torque values for the movement of land vehicle V, synergistically to the weakening control of the at least one synchronous reluctance motor 3.

In detail, the means for switching 14 are configured for switching the operation of the at least one synchronous reluctance motor 3 between a first operating configuration, in which the power of at least one synchronous reluctance motor 3 occurs via a so-called "star" connection of its phases, and a second operating configuration, in which the power of at least one synchronous reluctance motor 3 occurs via a so-called "delta" connection of its phases.

The characteristics and the effects of the star or delta configuration, as well as their implementation, are considered known and therefore they will not be further disclosed.

To this regard, it is noted that the propulsion unit 1 according to the present invention comprises at least one synchronous reluctance motor 3 of the type configured to be able to be powered with a double nominal voltage, according to the possibility of being able to be powered by a star or delta configuration.

By way of example but not of limitation, the attached Figure 8 shows the trend of the torque curve of an electric drive unit 2 according to the present invention, operated in a first and in a second operating configuration.

In the graph shown in Figure 8, the ordinate shows the torque values C and the abscissa shows the rotational speed N of at least one synchronous reluctance motor 3. The torque curves shown in this graph correspond to a first torque curve 15, or star coupling, and a second torque curve 16, or delta coupling, relative to the operation of the at least one synchronous reluctance motor 3 itself.

The first torque curve 15 corresponds to a torque curve that can be supplied from the drive unit 2 with the means for switching 14 provided in the first operating configuration of connection, wherein the phases of the stator 6 are star connected. The second torque curve 16 corresponds to a torque curve deliverable from the electric drive unit 1 with the means for switching 14 provided in the second operating configuration, wherein the phases of the stator 6 are delta connected.

It is understood that according to the characteristics of the electric drive unit 2, the trend of the first torque curve 15 and/or of the second torque curve 16 may undergo variations with respect to what is illustrated, without thereby departing from the scope of protection according to the present invention.

As an effect of the commutation between the first operating configuration (star) and the second operating configuration (delta), the electric drive unit 2 is able of delivering a maximum torque value also in the case in which it is driven at a higher rotation rate than that of the nominal velocity Nn provided for the at least one synchronous reluctance motor 3.

With reference to the above described, it is deduced how the electric drive unit 2 is able to operate effectively within a wide range of drive speed, ensuring effective operation of the propulsion unit 1 , since it can operate in weakening conditions and comprises means for switching 14 the connection of the stages of the stator 6.

To this regard, it is observed that in the electric drive units of the known type, the range of drive speed within which it is operated in constant torque conditions is limited and even operating in weakening conditions it is not possible to reach performance analogous to those of the at least one synchronous reluctance motor 3, above disclosed.

According to one version of the present invention, the at least one electric drive unit 2 comprises means for switching 14 which are separated from the at least one synchronous reluctance motor 3.

Further embodiments, not illustrated in the attached figures, wherein the means for switching 14 can be provided within an appropriate housing foreseen in the stator 6 of the synchronous reluctance motor 3, however, are possible without for this departing from the scope of protection according to the present invention.

By way of example, but not limitation, the means for switching 14 may comprise remote switches or similar devices switchable between the above mentioned first operating configuration and the second operating configuration, and vice versa. According to a further version of the present invention, the means for switching 14 may comprise electronic control devices adapted to operate the aforementioned switching between the first operating configuration and the second operating position and vice versa.

The means for switching 14 may be of the manually or automatically operable type, possibly remotely, without any limitation.

According to one version of the present invention, the propulsion unit 1 may comprise at least one logic unit 17 to control and/or command the switching of the means for switching 14 between the first operating configuration and the second operating configuration for each of the synchronous reluctance motors 3 provided in the propulsion unit 1 itself.

By way of example, in the case that a high torque at low rotation rates is required to the at least one pair of second semi-axles S2, the means for switching 14 can be switched to determine the first operating configuration (star configuration) for the at least one synchronous reluctance motor 3 associated with such at least one pair of second semi-axles S2.

In the case, instead, in which the at least one pair of second semi-axles S2 has to be driven at high rotation rates, albeit^' with a torque value lower than the maximum torque Cm deliverable by the propulsion unit 1 in the first operating configuration, the means for switching 14 can be switched in the second operating configuration (delta configuration).

According to one version of the present invention, the actuation of the means for switching 14 can be operated by the logic unit 17 in an automated way.

The latter, according to the required torque value and to the rotation rate of the at least one electric drive unit 2 to which such request is made, determines the switching of the means for switching 14 between the first and the second operating configuration, or vice versa.

By way of a non limiting example, the logic unit 17 can switch the means for switching 14 in the first operating configuration when a strong acceleration at low rotation velocities is required.

When, instead, a reduced torque, lower than the maximum torque deliverable by at least one electric drive unit 2, and in the presence of high rotational speed, is required, the logic unit 17 can switch the means of switching 14 in the second operating configuration.

According to one version of the present invention, the logic unit 17 may be a PLC or similar device suitable for the purpose.

According to one version of the present invention, the logic unit 17 is associable in feedback to the control means 13.

According to a further version of the present invention, the actuation of the means for switching 14 may be of the manual type.

In this case, the actuation of the means for switching 14 between the first and the second operating configuration, and vice versa, is manually operable by a user. According to such version, the logic unit 17 can act as a further control of the operation of the at least one synchronous reluctance motor 3 to which it is associated.

According to a further embodiment, the propulsion unit 1 can be operatively associated to at least one idle axle S2' of a land vehicle V according to procedures analogous to those previously disclosed.

As said, the propulsion unit 1 can be integrated in a land vehicle V comprising an endothermic M unit, in order to reduce the consumption of the latter. Moreover, it is observed that the propulsion unit 1 can operate within a wider speed range than that of the electric drive units of the known type, so that it is able to contribute to the traction of the land vehicle V among substantially the entire field of operation speed of the latter.

In practice, the propulsion unit 1 ensures an effective traction of at least one pair of second semi-axles S2 or of at least one second idle axle S2'.

In the case in which the propulsion unit 1 is provided in support of an endothermic unit M, the displacement and the power of the same can be, since part of the traction of the land vehicle V can be entrusted to the propulsion unit 1 itself, thus in advantage of a reduction in fuel consumption and a reduction of the weight of the endothermic unit M itself.

As said, the propulsion unit 1 is provided to support an endothermic unit M. According to this version, the propulsion unit 1 can serve as an auxiliary power source to promote, for example, a quick acceleration of the land vehicle V when required.

According to a further version of the present invention, the propulsion unit 1 can be installed in a non-motorised land vehicle T, such as a trailer, a trolley to be associated with a tractor vehicle, or the like (see Figure 6).

According to this version, the propulsion unit 1 may be associated with a trailer T and, more precisely, to at least one wheel and/or at least one pair of idle semi-axles S2 and/or at least one idle axle S2' of the trailer T.

Similar to what has been disclosed for the previous embodiment, the trailer T can comprise at least one system of accumulation/distribution of electrical energy B, not shown in detail, adapted to function as a source of accumulation and/or source of electrical energy for the propulsion unit 1 itself.

Reclaiming what has been previously_' described, the propulsion unit 1 can be associated to at least one pair of idle semi-axles S2, coupled to each other, and/or to at least one idle axle S2' of a non-motorised land vehicle T (with reference respectively to Figure 4 or 5).

The propulsion unit 1 , when installed on a non-motorised land vehicle, such as a trailer T, can act as the driving means for the same. In this regard, for example, the propulsion unit 1 can allow the handling of a trailer T parked in a depot, without requiring the use of additional means or vehicles of locomotion for towing the trailer T itself.

According to one version of the present invention, not illustrated in detail in the attached figures, the propulsion unit 1 may include at least one unit for the remote control of the at least one electrical unit 2. For this purpose, the propulsion unit 1 can comprise means for wireless communication configured to operatively connect the at least one control unit and the at least one electric drive unit 2 to each other. According to a version, not illustrated in the attached figures, the at least one control unit may comprise at least one antenna or the like for the reception/transmission of data.

In practice, according to such version, the operation of the propulsion unit 1 , and more specifically the actuation of the at least one electric drive unit 2, can be controlled remotely. For example, the movement of the trailer T can be controlled remotely through the use of suitable control means, such as a remote control or the like, configured to interface with the control unit through the sending/receiving remote data transmission.

According to a further aspect of the present invention, the propulsion unit 1 can act as a braking element of at least one wheel or at least one pair of idle semi-axles S2, coupled between them, or at least one idle axle S2', and cooperate with a braking system installed in the land vehicle V, T. In the case, in fact, in which the at least one electric drive unit 2 comprised in the propulsion unit 1 is operated as a electricity generator (braking phase) provides to apply a resistant torque to the at least one wheel and/or the at least a pair of idle semi-axles S2 and/or the at least one idle axle S2' to which it is operatively connected, promoting the braking thereof.

The propulsion unit 1 according to the present invention therefore allows the use of the at least one wheel and/or the at least one pair of idle semi-axles S2 and/or the at least one idle axle S2' to provide further traction or braking to a land vehicle V, T, according to a solution with high mechanical efficiency and simple to implement than the solutions of the known type.

In propulsion unit 1 , in fact, the at least one electric drive unit 2 has a large rate of operation speed within which is able to deliver optimum torque values, which corresponds, substantially, to the speed range provided for the operation of the land vehicle V, T. Therefore, the propulsion unit 1 does not require the use of mechanical gearboxes associated with the at least one electric drive unit 2, with the advantage of reducing the structural complexity of the propulsion unit 1 itself as well as the related implementation and maintenance costs.

According to a further version of the present invention, not illustrated in the attached figures, the propulsion unit 1 can be associated with the at least one wheel hub of a land vehicle, for operating the drive of the same in rotation.

Such a configuration of the propulsion unit 1 can be employed substantially in any type of land vehicle, regardless of the complexity and the size of the same.

According to one version of the present invention, a respective propulsion unit 1 can be connected to each wheel of a land vehicle, or only to some of them, so powering all or only some of the wheels of the land vehicle itself, according to specific operation requirements.

The propulsion unit 1 according to the present invention, could also be implemented in existing land vehicles, promoting an increase of their efficiency, in terms of fuel consumption and the performance achievable by the same.

The propulsion unit 1 according to the present invention achieves the advantages indicated above, with reference to the possibility of providing acceptable torque values within a wide speed range compared to that of solutions of the known type. In particular, the speed range within which the propulsion unit 1 is able to effectively operate may correspond substantially to the speed range provided for the operation of the land vehicle on which the propulsion unit 1 is installed.

The propulsion unit 1 described above may be subjected to numerous modifications and variations within the scope of protection of the following claims.

Claims

1. A unit for the propulsion of a land vehicle (V, T), said propulsion unit comprising at least one electric drive unit (2) operatively associable with at least one wheel and/or at least one pair of idle semi-axles (S2), said idle semi- axles (S2) being associable to each other, and/or at least one idle axle (S2') of said land vehicle (V, T), means (B) for the electric power supply of said propulsion unit, characterised in that said at least one electric drive unit (2) comprises at least one synchronous reluctance motor (3) of the type assisted by permanent magnets.

2. Propulsion unit for a land vehicle (V, T) according to claim 1, wherein said at least one synchronous reluctance motor (3) comprises a stator (6) provided with stator windings (10) and of a central seat (7) for housing a rotor (8) associated in a rotatable manned to said stator (6), said rotor (8) having a plurality of shaped recesses (12) for housing respective permanent magnets (11).

3. Propulsion unit for a land vehicle (V, T) according to claim 2, wherein said at least one electric drive unit (2) is directly connected, trough said at least one rotor (8) of said at least one synchronous reluctance motor (3) to said at least one wheel and/or said at least a pair of idle semi-axles (S2) and/or to said at least one idle axle (S2').

4. Propulsion unit for a land vehicle (V, T) according to claim 2, comprising at least one transmission (4) for the connection of said at least one electric drive unit (2) to said at least one wheel and/or said at least one pair of idle semi- axles (S2) and/or to said at least one idle axle (S2').

5. Propulsion unit for a land vehicle (V, T) according to claim 1, comprising means for switching (14) the power supplied to said at least one synchronous reluctance motor (3) between a first operating configuration and a second operating configuration, and vice versa, for the delivery of variable torque and power as function of the rotation rate of said synchronous reluctance motor (3).

6. Propulsion unit for a land vehicle (V, T) according to claim 5, comprising at least one logic unit (17) to control the switching of said means for switching (14).

7. Propulsion unit for a land vehicle (V, T) according to claim 1, wherein said land vehicle (V) is a motor or comprises at least one propulsion unit (M) of the endothermic or electric type.

8. Propulsion unit for a land vehicle (V, T) according to claim 1, wherein said land vehicle (T) is a trailer or a non-motorised vehicle comprising at least a pair of idle semi-axles (S2) coupled to each other and/or at least one idle axle (S2').

9. Propulsion unit for a land vehicle (V, T) according to claim 1, wherein said at least one electric drive unit (2) is operatively connected to at least one wheel hub of said land vehicle (V, T) in order to drive it.

10. Propulsion unit for a land vehicle (V, T) according to claim 6, comprising means for communication of the wireless type for the transmission/reception of data, said means for communication being operatively connected to said logic unit (17) to remotely control the operation of said at least one electric drive unit (2).