SE1951175A1 - A hybrid vehicular work machine - Google Patents

Abstract

The present disclosure relates to a vehicular work machine (10) comprising a first electric motor arrangement (31) comprising one or more electric motors (21, 21’), and a second electric motor arrangement (32) comprising one or more electric motors (22, 22’) separate from said one or more electric motors (21, 21’) of the first electric motor arrangement (31). The vehicular work machine (10) further comprises a power connection (8) adapted to be connected to an external electric power source (17), an energy storage arrangement (23) and a hydraulic pump assembly (24) that is adapted to power hydraulic devices (5, 18, 19, 20) comprised in the vehicular work machine (10). At least one electric motor (21, 21’; 22, 22') in each electric motor arrangement (31, 32) is adapted to propel the hydraulic pump assembly (24). Said one or more electric motors (21, 21’) in the first electric motor arrangement (31) are arranged to be electrically powered from the external power supply (17), and said one or more electric motors (22, 22’) in the second electric motor arrangement (32) are arranged to be electrically powered from the energy storage arrangement (23).

Description

TITLEA hybrid vehicular work machine TECHNICAL FIELD This present disclosure relates to a vehicular work machine comprising a firstelectric motor arrangement with one or more electric motors, a second electricmotor arrangement with one or more electric motors. The vehicular workmachine further comprises a power connection adapted to be connected to anexternal electric power source, an energy storage arrangement and ahydraulic pump assembly that is adapted to power hydraulic devices.

BACKGROUND Machines referred to as demolition robots are remote-controlled workingmachines intended for different demolition operations, in which the operatorwalks beside the machine and controls its different movements. The operatordoes this using a remote control that has two control sticks and a series ofdifferent buttons and knobs. The machine is used in several different workingmodes. lt is first moved up to the working surface, e.g. a wall, to bedemolished. lts support legs are then lowered so that the machine standssteady. The actual demolition work then begins.

A demolition robot can be powered by electricity and then is supplied withpower through a power cable from a fixed electrical grid. The electrical energyis converted to hydraulic energy with the aid of an electrically driven pumpdevice, which hydraulic energy in the form of a hydraulic medium underpressure is led to the various active units of the work machine via valves. Theelectric motor that is used to drive the pump device of the work machine istypically of three-phase, low-voltage type, with a rated voltage of 380-500 Vand a frequency of 50 or 60 Hz.

For work machines, it has been proposed to use a battery, either alone or asa complement to the fixed electrical grid for work machines. ln EP 2738035 there is a mining vehicle with one electric motor for running ahydraulic pump and another electric motor for moving the mining vehicle. Eachone of the motors can be energized by means of an external electric powernetwork or a battery power source, and when the electric power supply to theelectric motors is only provided from the external electric power network, thebattery power source can be charged.

However, charging a battery from a three-phase electric power networkrequires corresponding charging equipment that is expensive, and normallyneeds to be connected to neutral. Only using one phase for charging, using a traditional charger, is insufficient for many normal situations. lt is therefore desired to provide an electric work machine that is equipped forconnection to both an external power supply such as a power network and aninternal power source such as a battery, where sufficient operation ismaintained for normal work situations independently of which power source that is used and where a separate battery charger is not needed.

SUMMARY The object of the present disclosure relates to providing an electric workmachine that is equipped for connection to both an external power supply suchas a power network and an internal power source such as a battery, wheresufficient operation is maintained for normal work situations independently ofwhich power source that is used.

This object is obtained by means of a vehicular work machine comprising afirst electric motor arrangement comprising one or more electric motors, anda second electric motor arrangement comprising one or more electric motorsseparate from said one or more electric motors of the first electric motorarrangement. The vehicular work machine further comprises a power connection adapted to be connected to an external electric power source, an energy storage arrangement and a hydraulic pump assembly that is adaptedto power hydraulic devices comprised in the vehicular work machine. At leastone electric motor in each electric motor arrangement is adapted to propel thehydraulic pump assembly. Said one or more electric motors in the first electricmotor arrangement are arranged to be electrically powered from the externalpower supply, and said one or more electric motors in the second electricmotor arrangement are arranged to be electrically powered from the energy storage arrangement.

This confers an advantage of enabling differentiated power sources for electricmotors driving a common hydraulic pump assembly in the vehicular workmachine. ln this way, a sufficient operation can be maintained for normal worksituations independently of which power source that is used, enabling aversatile use of the vehicular work machine.

According to some aspects, the vehicular work machine is adapted for acharging mode of operation where the first electric motor arrangement isadapted to propel the second electric motor arrangement and to run thesecond electric motor arrangement as a generator that is adapted to chargethe energy storage arrangement.

This confers an advantage of avoiding the need for a separate charger.

According to some aspects, in the charging mode of operation the first electricmotor arrangement also propels the hydraulic pump assembly.

This confers an advantage of being able to operate the vehicular work machineduring charging.

According to some aspects, the energy storage arrangement is connected tothe second electric motor arrangement via a motor driver assembly that is adapted to convert the voltage provided by energy storage arrangement to a suitable voltage for the second electric motor arrangement. For example, themotor driver assembly is adapted to control a rate of power supplied from theenergy storage arrangement in dependence of available power from theexternal power supply and power required by the hydraulic pump assembly.

This confers an advantage of using available power in an efficient manner.

According to some aspects, the motor driver assembly is adapted to work asa charger in the charging mode.

This confers an advantage of using one component for different purposes.

According to some aspects, the first motor driver assembly is adapted tocontrol a rate of charging of the energy storage arrangement in dependenceof available power from the external power supply and power required by thehydraulic pump assembly.

This confers an advantage of charging the energy storage arrangement in anefficient manner.

According to some aspects, the vehicular work machine is adapted for - Afirst mode of operation where only the first electric motor arrangementpropels the hydraulic pump assembly.

- A second mode of operation where only the second electric motorarrangement propels the hydraulic pump assembly.

- A third mode of operation where both electric motor arrangementspropel the hydraulic pump assembly.

This confers an advantage of having a versatile propulsion of the hydraulicpump assembly, such that the electric motor arrangements are used in anefficient manner.

According to some aspects, the third mode of operation comprises at leastone of the following sub-modes of operation: - A starting mode, where the second electric motor arrangement isadapted to run the first electric motor arrangement before it is poweredfrom the external electric power source.

- A common driving mode, where both electric motor arrangements are adapted to propel the hydraulic pump assembly.

This confers an advantage of enabling an uncomplicated and reliable soft startof the second electric motor arrangement.

According to some aspects, the vehicular work machine comprises a single-phase battery charger that is connectable to the external electric power sourcevia a charger contactor.

This confers an advantage of enabling auxiliary charging in an inexpensivemanner.

There are also disclosed herein methods associated with the above-mentioned advantages.

Other examples are disclosed in the dependent claims.

BRIEF DESCRIPTION OF DRAWINGSThe present disclosure will now be described more in detail with reference tothe accompanying figures wherein: Figure 1 shows a first view of a demolition robot and a remote control; Figure 2 shows a second view of the demolition robot; Figure 3 shows a schematical view of components comprised in thedemolition robot; Figure 4 shows a schematical view of an example of a motor configuration; Figure5 shows a schematical view of another example of a motorconfiguration; Figure 6 shows a schematical view of yet another example of a motorconfiguration; and Figure7 shows a flowchart for a method according to the present disclosure.

DETAILED DESCRIPTION With reference to Figure 1, there is a working machine 10 in the form of ademolition robot which is electrically driven and which has a power connection8. ln the figures, the connection 8 is shown in a detached state, but it is duringoperation connected to a cable leading to an external electric power source17 (schematically indicated in Figure 1), generally forthree-phase current. Themachine is driven by caterpillar tracks 6 and has a rotating tower 7. An armconsisting of several parts is secured to the tower 7.

The machine has four support legs 5 which here are shown fully raised. Theoperator operates the machine with the aid of a remote control 11 which is inthis case worn over the operator's shoulders. However, it may of course alsobe secured in a different manner, e.g. by means of a waist belt. The remotecontrol has a left control stick 12 and a right control stick 13.

Figure 2 shows the demolition robot 10 in more detail with some of theprotective casings removed. lts support legs 5 are lowered so that the machinerests steady on its four support legs. As mentioned, the machine has an armconsisting of three parts. A first arm 1 is hinged to the rotating tower 7 of themachine and can be swung with the aid of a first hydraulic cylinder 18, theupper end of which is seen in the left part of the arm. A second arm 2 is securedto the first arm 1. lt is inclined with the aid of a second hydraulic cylinder 19on the front side of the first arm 1. The second arm 2 also has an innertelescopically extendable part which increases the range of the machine. lt isoperated by a hydraulic cylinder which is placed within the second arm 2 and is therefore completely concealed. A third arm 3 is secured to the outer end ofthe second arm 2, and is swung by a third hydraulic cylinder 20 on the insideof the second arm 2.

The outer end of the third arm 3 is designed in such a manner that it can besecured to a mounting plate 9 mounted on the rear side of a demolition tool 4.For the sake of clarity, the tool 4 and the mounting plate 9 are shown separatedfrom one another and from the outer end of the third arm 3. ln Figure 1, aschematical breaker 4 for chipping concrete or the like, is shown mounted. ltcan be exchanged for a concrete crusher for breaking and cutting material.

With reference also to Figure 3, The demolition robot 10 comprises a firstelectric motor 21, a second electric motor 22, a battery 23 and a hydraulicpump assembly 24 that is adapted to power the hydraulic cylinders 18, 19, 20and other hydraulic devices such as the support legs 5 and a propulsion unitfor the caterpillar tracks 6 in a previously known manner.

According to the present disclosure, the first electric motor 21 is adapted tobe powered only from the external electric power source 17 via the powercable and the second electric motor 22 adapted to be powered only from thebattery 23. For that purpose, the battery 23 is connected to the second electricmotor 22 via a motor driver assembly 25 that is adapted to convert the voltageprovided by the battery 23 to a suitable voltage for the second motorarrangement 22.

Both electric motors 22 are connectable to the hydraulic pump assembly 24,according to some aspects via a first clutch arrangement 26a and a secondclutch arrangement 26b. More in detail, the first electric motor 21 is connectedto a first power transferring shaft 27a and the second electric motor 22 isconnected to a second power transferring shaft 27b. The first powertransferring shaft 27a is connectable to a third power transferring shaft 27cthat is adapted to drive the hydraulic pump assembly 24 via the first clutch arrangement 26a, and the second transferring shaft 27b is connectable to thethird power transferring shaft 27c via the second clutch arrangement 26b. ln a first mode of operation, the first clutch arrangement 26a is adapted toconnect the first power transferring shaft 27a to the third power transferringshaft 27c and the second clutch arrangement 26b is adapted to disconnect thesecond transferring shaft 27b from the third power transferring shaft 27c. lnthe first mode of operation, only the first electric motor 21 is propelling thehydraulic pump assembly 24, the demolition robot 10 then only being poweredby means of the external electric power source 17. ln a second mode of operation, the second clutch arrangement 26b is adaptedto connect the second power transferring shaft 27b to the third powertransferring shaft 27c and the second clutch arrangement 26b is adapted todisconnect the first transferring shaft 27a from the third power transferringshaft 27c. ln the second mode of operation, only the second electric motor 22is propelling the hydraulic pump assembly 24, the demolition robot 10 thenonly being powered by means of the battery 23. ln a third mode of operation, the first clutch arrangement 26a is adapted toconnect the first power transferring shaft 27a to the third power transferringshaft 27c, and the second clutch arrangement 26b is adapted to connect thesecond power transferring shaft 27b to the third power transferring shaft 27c.

The third mode of operation, where the electric motors 21, 22 are mechanicallyconnected to each other, comprises three different sub-modes of operation; a starting mode, a common driving mode and a charging mode. ln the starting mode, the second electric motor 22 is adapted to run the firstelectric motor 21 before it is powered from the external electric power source17, enabling a soft start of the first electric motor 21 that minimizes currentpeaks during start of the first electric motor 21. After start-up, the first electric motor 21 is powered from the external electric power source 17. Then anymode of operation where the first electric motor 21 is running can follow. ln the common driving mode, both electric motors are adapted to propel thehydraulic pump assembly 24, conferring a maximum available working powerto the demolition robot 10. ln the charging mode, the first electric motor 21 is adapted to run the secondelectric motor 22 as a generator. ln this case, the motor driver assembly 25works as a battery charger that can be controlled for charging the battery 23.ln the charging mode, according to some aspects, the third power transferringshaft 27c can either be connected for driving the hydraulic pump assembly 24or disconnected from the hydraulic pump assembly 24. This is enabled bymeans of a third clutch arrangement 26c that is adapted to connect anddisconnect the third power transferring shaft 27c to and from the hydraulicpump assembly 24. ln the former case, when the third power transferring shaft 27c is connectedfor driving the hydraulic pump assembly 24, the excess available power fromthe external electric power source 17, not being required by the hydraulicpump assembly 24, may be used for charging the battery 23 via the firstelectric motor 21. ln this case, the motor driver assembly 25 is adapted tocontrol a rate of charging of the battery 23 in dependence of available powerfrom the external power source 17 and power required by the hydraulic pumpassembly 24. lf more power is required by the hydraulic pump assembly 24than is available from the external power source 17, the motor driver assembly25 is adapted to control a rate of power supplied from the battery 23 independence of the power needed. ln the latter case, when the third power transferring shaft 27c is disconnectedfrom the hydraulic pump assembly 24, all available power from the external electric power source 17 can be used for charging the battery 23 via the firstelectric motor 21.

The electric motors 21, 22 are not sensitive for overvoltage or surge on theexternal electric power source 17, enabling a robust charging. The batteryvoltage system is isolated from the incoming 3-phase power from the externalelectric power source 17. By having two electric motors, the need for aseparate three-phase charger is eliminated by using the second electric motor22 as a generator and the driver assembly 25 as a battery charger. instead ofone larger electric motor, two smaller electric motors can be used. Motor sizesmay be chosen in dependence of the power needed when running on battery power without grid connection.

According to some aspects, as indicted with dotted lines, a single-phasebattery charger 28 is connected to the external electric power source 17 via acharger contactor 29. The single-phase battery charger 28 is of a common andinexpensive type and is used for charging the battery when a need arises. itshould be noted that the efficiency of the battery charging during the chargingmode exceeds the efficiency of the battery charging by means of the single-phase battery charger 28. The single-phase battery charger 28 can be usedfor overnight charging or for charging with lower power. This can automaticallybe connected when the first electric motor 21 is turned off, by means of thecharger contactor 29.

According to some aspects, as indicted with dotted lines, in case the startingmode is not implemented, or not working, the first electric motor isconventionaiiy started by means of a motor contactor 30. in this case, aconventional soft start arrangement is preferably used in order to reduce themagnitude of electric current during start.

The present disciosure is not limited to the examples above, but may varyfreeiy within the scope of the appended ciaims. For example, the electric 11 motors 21, 22 are connectable to the hydraulic pump assembly 24 via otherarrangements than said clutch arrangements 26a, 26b.

The workings of the components described above for the demolition robot 10are according to some aspects controlled by one or more control units 33, asschematically indicated in Figure 3.

When the demolition robot 10 is in the form of a remote-controlled demolitionrobot it further comprises a radio module that is used for communicating withthe remote control 11. lt is also conceivabie that a wired control is used, wheresuch a wire may be connected through or along with the power connection 8.

Although the present disclosure has been described for a demolition robot 10that is remotely controlled, the present disclosure is applicable for any type ofvehicular work machine.

Generally, the demolition robot 10 comprises a first electric motor arrangement31 comprising one or more electric motors 21, 21' as indicated schematicallywith dashed lines in Figure 3, which in the case of two or more electric motors21, 21' can be more or less mechanically interconnected. Generally, thedemolition robot 10 further comprises a second electric motor arrangement 32comprising one or more electric motors 22, 22” as indicated schematically withdashed lines in Figure 3, which in the case of two or more electric motors 21,21 ” can be more or less mechanically interconnected. Said one or more electricmotors 21, 21” comprised in the first electric motor arrangement 31 are allarranged to be electrically powered from an external power supply only, suchas a power grid 17, and said one or more electric motors 22, 22' comprised inthe second electric motor arrangement 32 are all arranged to be electricallypowered from a battery 23 only. Generally, the battery is constituted by anenergy storage arrangement 23 of a suitable kind that is adapted to be charged 12 The examples presented above are only disclosed for providing anunderstanding of the present disclosure. Generally, the third mode ofoperation, where the electric motors 21, 22 are mechanically connected toeach other, comprises at least one of said sub-modes, the starting mode andthe common driving mode. The inventive concept relies in the fact that oneelectric motor, or electric motor arrangement, is arranged to be electricallypowered from an external power supply, such as a power grid, and anotherelectric motor, or electric motor arrangement, is arranged to be electricallypowered from an internal power source, where the internal power source maybe chargeable and may hold a charged amount of electric energy, generally being constituted by an energy storage arrangement 23.

According to some aspects, one electric motor, or electric motor arrangement,is arranged to be electrically powered mainly from an external power supply,and another electric motor, or electric motor arrangement, is arranged to beelectrically powered mainly from an internal power source. The internal powersource is chargeable and can hold a charged amount of electric energy,generally being constituted by an energy storage arrangement 23. ln this context, the term powered refers to acquiring electric power for runningone or more electric motors. According to some aspects, an electric motor canhave electrical connections that for example are associated with sensors andcontrol circuits at the electric motor in question. Such electrical connectionsare of a low-voltage type, normally about 5V, and are relaying electricalcurrents of relatively low magnitudes, and are not associated with powering an electrical motor.The hydraulic pump assembly 24 can comprise one or more hydraulic pumps.The supporting legs are optional, and the number of supporting legs may vary but should be at least two when present. lnstead of supporting legs, dozerblades can be used. 13 The external electric power source is according to some aspects a one-phasepowers source, two-phase power source or three-phase power source, in any case with or without a neutral and/or a ground connection.

The caterpillar tracks 6 are according to some aspects directly electrically driven.

According to some aspects, the electric motors can be arranged in manydifferent manners. ln Figure 4, only schematically showing how the electricmotors are connected to the hydraulic pump assembly 24, there is a firstelectric motor 21 according to the example above and a second electric motor22 according to the example above. This means that there is only one electric21 motor in a first electric motor arrangement 31 and only one electric motor22 in a second electric motor arrangement 32. Of course there can be anynumber of electric motors in the respective electric motor arrangement, here only an example showing a principle is disclosed.

The first electric motor 21 is connectable to the second electric motor 22 viaa first power transferring shaft 34a, a first clutch arrangement 35a and asecond power transferring shaft 34b. The second electric motor 22 isconnectable to the hydraulic pump assembly 24 via the second powertransferring shaft 34b, a second clutch arrangement 35b and a third powertransferring shaft 34c. Here, the first clutch arrangement 35a is adapted toconnect or disconnect a mechanical connection between the electric motors21, 22, and the second clutch arrangement 35b is adapted to connect ordisconnect a mechanical connection between the second electric motor 22and the hydraulic pump assembly 24.

This means that the second electric motor 22 can be mechanically connectedto the hydraulic pump assembly 24, with or without being mechanicallyconnected to the first electric motor 21. The first electric motor 21 can be 14 mechanically connected to the second electric motor 22 only, admittingcharging of the battery 23 without propelling the hydraulic pump assembly 24,or mechanically connected to the hydraulic pump assembly 24 together withthe second electric motor 22. ln Figure 5, there is a similar arrangement, but here the first electric motor 21and the second electric motor 22 have changed places. The second electricmotor 22 is connectable to the first electric motor 21 via a first powertransferring shaft 36a, a first clutch arrangement 37a and a second powertransferring shaft 36b. The first electric motor 21 is connectable to thehydraulic pump assembly 24 via the second power transferring shaft 36b, asecond clutch arrangement 37b and a third power transferring shaft 36c. Here,the first clutch arrangement 37a is adapted to connect or disconnect amechanical connection between the electric motors 21, 22, and the secondclutch arrangement 37b is adapted to connect or disconnect a mechanicalconnection between the first electric motor 21 and the hydraulic pumpassembly 24.

This means that the first electric motor 21 can be mechanically connected tothe hydraulic pump assembly 24, with or without being mechanicallyconnected to the second electric motor 22. The second electric motor 22 canbe mechanically connected to the first electric motor 21 only, admittingcharging of the battery 23 without propelling the hydraulic pump assembly 24,or mechanically connected to the hydraulic pump assembly 24 together withthe first electric motor 21. ln Figure 6, a parallel configuration is shown. Here the first electric motor 21and the second electric motor 22 are mounted in parallel with respect to eachother and the hydraulic pump assembly 24. More in detail, the first electricmotor 21 is mechanically connected to a first power transferring shaft 38a, thesecond electric motor 22 is mechanically connected to a second powertransferring shaft 38b and the hydraulic pump assembly 24 is mechanically connected to a third power transferring shaft 38c. These power transferringshafts 38a, 38b, 38c are connectable via a common clutch arrangement 39that according to some aspects comprises a belt transmission.

This means that the first electric motor 21, the second electric motor 22 andthe hydraulic pump assembly 24 are connectable to each other via thecommon clutch arrangement 39 that according to some aspects is adapted tomechanically connect the first electric motor 21, the second electric motor 22and the hydraulic pump assembly 24 irrespective of each other.

The clutch arrangements 26a, 26b, 26c; 35a, 35b, 35c; 37a, 37b, 37c; 39 aregenerally constituted by power transferring arrangements. According to someaspects, each one of the power transferring arrangement 26a, 26b, 26c; 35a,35b, 35c; 37a, 37b, 37c; 39 comprises at least one of a clutch assembly anda gear assembly. By means of a gear assembly, rotational speeds can beconverted to suitable magnitudes.

According to some aspects, one or more power transferring arrangements26a, 26b, 26c; 35a, 35b, 35c; 37a, 37b, 37c; 39 is/are omitted, such that twoor more of the power transferring shafts 27a, 27b, 27c; 34a, 34b, 34c; 36a,36b, 36c; 38a, 38b, 38c is/are constituted by one coherent power transferringshaft. This means that according to some aspects, according to one example,there are no power transferring arrangements 26a, 26b, 26c; 35a, 35b, 35c;37a, 37b, 370; 39 at all, and all electric motors 21,22 and the hydraulic pumpassembly 24 are always directly mechanically connected to each other.

Having power transferring arrangements 26a; 35a; 39 adapted for disengagingsaid one or more electric motors 21, 21' in the first electric motor arrangement31 reduces the risk of driving one or more of said one or more electric motors21, 21” in the first electric motor arrangement 31 backwards and provide anelectric current into the external power source 17 if the motor contactor 30 16 would turn on. Without such power transferring arrangements 26a; 35a; 39,this can be avoiding by monitoring the motor contactor 30.

Having power transferring arrangements 26c; 35b; 37b; 39 adapted fordisengaging the hydraulic pump assembly 24 reduces the risk of unpredictablemovements. Without such power transferring arrangements 26c; 35b; 37b; 39,this can be avoided by monitoring the hydraulic pressure in the system.

Generally, due to different kinds of power transferring arrangements 26c; 35b;37b; 39 and that one or more power transferring arrangements 26c; 35b; 37b;39 as described is/are not used, one or more of the electric motor/motors is/areadapted to propel the hydraulic pump assembly 24, and the first electric motorarrangement 31 is adapted to propel the second electric motor arrangement32.

Generally, this means that: - ln the first mode of operation only the first electric motor arrangement31 propels the hydraulic pump assembly 24, - ln the second mode of operation only the second electric motorarrangement 32 propels the hydraulic pump assembly 24, and - in the third mode of operation both electric motor arrangements 31, 32propel the hydraulic pump assembly 24.

Furthermore, generally, in the charging mode of operation, the first electricmotor arrangement 31 propels the second electric motor arrangement 32.According to some aspects, in the charging mode of operation, the first electricmotor arrangement 31 also propels the hydraulic pump assembly 24.

According to some aspects, the first electric motor arrangement 31 comprisesone or more asynchronous electric motors 21, 21 '_ This is advantageous sincean asynchronous motor is less expensive than a 3-phase battery charger withthe same power, and normally also less expensive than many other types of 17 electric motors. Furthermore, an asynchronous motor can be connected to athree-phase voltage without connection to an electric neutral. Most batterychargers require connection to neutral which is not available on all power supply networks.

Furthermore, an asynchronous motor is robust in its construction and iscapable of being mounted in a demolition robot. A three-phase charger isusually adapted to be wall-hung or possibly sitting on a forklift truck, a muchless harsh environment than in a demolition robot.

Furthermore, an asynchronous motor is easy to adapt to different voltages andfrequencies in different markets. Since the selection of on-board chargers isvery limited, it would according to an example be very difficult and costly toprovide a charger each separate market (e.g. for Japan (2x200V), South Africa(3x525V) and Canada (3x575V)). But asynchronous motors with the rightvoltage are available for all markets, making adaptation of the demolition robotto match each present market is uncomplicated and cost effective.

According to some aspects, the first electric motor arrangement 31 comprisesone or more electric motors 21, 21' of relatively large powers, with thepossibility of limiting power output of the motor. For example, an electric motorrated for 32A current can be limited to loading the external power supply withonly 16A if there is only a connection to 16A available. lf 32A is available, thecorresponding power can of course be used.

The more the first electric motor arrangement 31 may be loaded, the more thepower output of the second electric motor arrangement 32 may be limited,which in turn will provide longer battery life. Because the batteries are a majorpart of the hybrid cost, having one or more electric motors 21, 21' of relativelylarge powers in the first electric motor arrangement 31, the lifetime of therelatively expensive battery can be extended. 18 According to some aspects, the motors in the electric motor arrangements 31,32 can comprise asynchronous motors, synchronous motors, universal motors and/or permanent magnet motors.

Generally, the present disclosure relates to a vehicuiar work machine 10comprising a first electric motor arrangement 31 comprising one or moreelectric motors 21, 21', and a second electric motor arrangement 32comprising one or more electric motors 22, 22' separate from said one or moreelectric motors 21, 21' of the first electric motor arrangement 31, where thevehicuiar work machine 10 further comprises a power connection 8 adaptedto be connected to an external electric power source 17, an energy storagearrangement 23 and a hydraulic pump assembly 24 that is adapted to powerhydraulic devices 5, 18, 19, 20 comprised in the vehicuiar work machine 10,where at least one electric motor 21, 21'; 22, 22' in each electric motorarrangement 31, 32 is adapted to propel the hydraulic pump assembly 24.Said one or more electric motors 21, 21” in the first electric motor arrangement31 are arranged to be electrically powered from the external power supply 17,and said one or more electric motors 22, 22' in the second electric motorarrangement 32 are arranged to be electrically powered from the energystorage arrangement 23.

According to some aspects, said one or more electric motors 21, 21' in thefirst electric motor arrangement 31 are arranged to be electrically poweredmainly from the external power supply 17, and said one or more electric motors22, 22' in the second electric motor arrangement 32 are arranged to beelectrically powered mainly from the energy storage arrangement 23.

According to some aspects, the vehicuiar work machine 10 is adapted for acharging mode of operation where the first electric motor arrangement 31 isadapted to propel the second electric motor arrangement 32 and to run thesecond electric motor arrangement 32 as a generator that is adapted to chargethe energy storage arrangement 23. 19 According to some aspects, the charging mode of operation, the first electricmotor arrangement 31 also propels the hydraulic pump assembly 24.

According to some aspects, the energy storage arrangement 23 is connectedto the second electric motor arrangement 32 via a motor driver assembly 25that is adapted to convert the voltage provided by energy storage arrangement23 to a suitable voltage for the second electric motor arrangement 32.

According to some aspects, the motor driver assembly 25 is adapted to controla rate of power supplied from the energy storage arrangement 23 independence of available power from the external power supply 17 and powerrequired by the hydraulic pump assembly 24.

According to some aspects, the motor driver assembly 25 is adapted to workas a charger in the charging mode.

According to some aspects, the first motor driver assembly 25 is adapted tocontrol a rate of charging of the energy storage arrangement 23 in dependenceof available power from the external power supply 17 and power required bythe hydraulic pump assembly 24.

According to some aspects, the vehicular work machine 10 is adapted for - a first mode of operation where only the first electric motor arrangement31 propels the hydraulic pump assembly 24, - a second mode of operation where only the second electric motorarrangement 32 propels the hydraulic pump assembly 24, and - a third mode of operation where both electric motor arrangements 31,32 propel the hydraulic pump assembly 24.

According to some aspects, the third mode of operation comprises at leastone of the following sub-modes of operation: - a starting mode, where the second electric motor arrangement 32 isadapted to run the first electric motor arrangement 31 before it ispowered from the external electric power source 17; - a common driving mode, where both electric motor arrangements 31,32 are adapted to propel the hydraulic pump assembly 24.

According to some aspects, the vehicular work machine 10 comprises asingle-phase battery charger 28 that is connectable to the external electricpower source 17 via a charger contactor 29.

According to some aspects, the first electric motor arrangement 31 comprises one or more asynchronous electric motors 21, 21 ”_ Generally, with reference to Figure 7, the present disclosure also relates to amethod for a vehicular work machine 10, having an energy storagearrangement 23, a first electric motor arrangement 31 using one or moreelectric motors 21, 21 ', and a second electric motor arrangement 32 using oneor more electric motors 22, 22”. The method comprises: powering 101 the first electric motor arrangement 31 from an external electricpower source 17; and powering 102 the second electric motor arrangement 32 from the energystorage arrangement 23.

According to some aspects, in a charging mode of operation, the first electricmotor arrangement 31 is used for running the second electric motorarrangement 32 as a generator that is used for charging the energy storage affangement 23.

According to some aspects, in a first mode of operation, the method comprisesonly using the first electric motor arrangement 31 for propelling a hydraulicpump assembly 24 used in the vehicular work machine 10, in a second modeof operation, the method comprises only using the second electric motor 21 arrangement 32 for propelling the hydraulic pump assembly 24, and in a thirdmode of operation, using both electric motor arrangements 31, 32 forpropelling the hydraulic pump assembly 24.

According to some aspects, the third mode of operation comprises at leastone of the following sub-modes of operation: - a starting mode, where the second electric motor arrangement 32 isused for propelling the first electric motor arrangement 31 before it ispowered from the external electric power source 17; - a common driving mode, where both electric motor arrangements 31, 32 are used for propelling the hydraulic pump assembly 24.

Claims (16)

1. A vehicular work machine (10) comprising a first electric motorarrangement (31) comprising one or more electric motors (21, 21'), and asecond electric motor arrangement (32) comprising one or more electricmotors (22, 22”) separate from said one or more electric motors (21, 21') ofthe first electric motor arrangement (31), where the vehicular work machine(10) further comprises a power connection (8) adapted to be connected to anexternal electric power source (17), an energy storage arrangement (23) anda hydraulic pump assembly (24) that is adapted to power hydraulic devices (5,18, 19, 20) comprised in the vehicular work machine (10), where at least oneelectric motor (21, 21 ”; 22, 22') in each electric motor arrangement (31, 32) isadapted to propel the hydraulic pump assembly (24), characterized in thatsaid one or more electric motors (21, 21') in the first electric motorarrangement (31) are arranged to be electrically powered from the externalpower supply (17), and said one or more electric motors (22, 22') in the secondelectric motor arrangement (32) are arranged to be electrically powered fromthe energy storage arrangement (23). work machine

2. The vehicular (10) characterized in that said one or more electric motors (21, 21') in the first according to claim 1,electric motor arrangement (31) are arranged to be electrically powered mainlyfrom the external power supply (17), and said one or more electric motors (22,22') in the second electric motor arrangement (32) are arranged to beelectrically powered mainly from the energy storage arrangement (23).

3. The vehicular work machine (10) according to any one of theclaims 1 or 2, characterized in that the vehicular work machine (10) isadapted for a charging mode of operation where the first electric motorarrangement (31) is adapted to propel the second electric motor arrangement(32) and to run the second electric motor arrangement (32) as a generator thatis adapted to charge the energy storage arrangement (23).

4. The vehicular work machine (10) characterized in that in the charging mode of operation, the first electric motor according to claim 3, arrangement (31) also propels the hydraulic pump assembly (24).

5. The vehicular work machine (10) according to any one of theclaims 2-4, characterized in that the energy storage arrangement (23) isconnected to the second electric motor arrangement (32) via a motor driverassembly (25) that is adapted to convert the voltage provided by energystorage arrangement (23) to a suitable voltage for the second electric motorarrangement (32). work machine

6. The vehicular (10) characterized in that the motor driver assembly (25) is adapted to control a according to claim 5,rate of power supplied from the energy storage arrangement (23) independence of available power from the external power supply (17) and powerrequired by the hydraulic pump assembly (24).

7. The vehicular work machine (10) according to any one of theclaims 5 or 6, characterized in that the motor driver assembly (25) is adaptedto work as a charger in the charging mode. work machine

8. The vehicular (10) characterized in that the first motor driver assembly (25) is adapted to control according to claim 7,a rate of charging of the energy storage arrangement (23) in dependence ofavailable power from the external power supply (17) and power required bythe hydraulic pump assembly (24).

9. The vehicular work machine (10) according to any one of theprevious claims, characterized in that the vehicular work machine (10) isadapted for - a first mode of operation where only the first electric motor arrangement (31) propels the hydraulic pump assembly (24), - a second mode of operation where only the second electric motorarrangement (32) propels the hydraulic pump assembly (24), and- a third mode of operation where both electric motor arrangements (31, 32) propel the hydraulic pump assembly (24).

10. The vehicular work machine (10) according to claim 9,characterized in that the third mode of operation comprises at least one ofthe following sub-modes of operation: - a starting mode, where the second electric motor arrangement (32) isadapted to run the first electric motor arrangement (31) before it ispowered from the external electric power source (17); - a common driving mode, where both electric motor arrangements (31, 32) are adapted to propel the hydraulic pump assembly (24).

11. The vehicular work machine (10) according to any one of theprevious claims, characterized in that the vehicular work machine (10)comprises a single-phase battery charger (28) that is connectable to theexternal electric power source (17) via a charger contactor (29).

12. The vehicular work machine (10) according to any one of theprevious claims, characterized in that the first electric motor arrangement (31) comprises one or more asynchronous electric motors (21, 21').

13. A method for a vehicular work machine (10), having an energystorage arrangement (23), a first electric motor arrangement (31) using one ormore electric motors (21, 21”), and a second electric motor arrangement (32)using one or more electric motors (22, 22'), wherein the method comprises: powering (101) the first electric motor arrangement (31) from anexternal electric power source (17); and powering (102) the second electric motor arrangement (32) fromthe energy storage arrangement (23).

14. The method according to claim 13, wherein, in a charging mode ofoperation, the first electric motor arrangement (31) is used for running thesecond electric motor arrangement (32) as a generator that is used forcharging the energy storage arrangement (23).

15. The method according to any one of the claims 13 or 14, wherein,in a first mode of operation, the method comprises only using the first electricmotor arrangement (31) for propelling a hydraulic pump assembly (24) usedin the vehicular work machine (10), in a second mode of operation, the methodcomprises only using the second electric motor arrangement (32) forpropelling the hydraulic pump assembly 24, and in a third mode of operation,using both electric motor arrangements (31, 32) for propelling the hydraulicpump assembly (24).

16. The method according to claim 15, wherein the third mode ofoperation comprises at least one of the following sub-modes of operation: - a starting mode, where the second electric motor arrangement (32) isused for propelling the first electric motor arrangement (31) before it ispowered from the external electric power source (17); - a common driving mode, where both electric motor arrangements (31,32) are used for propelling the hydraulic pump assembly (24).