SE543145C2 - Method and system for pre-charging a rechargeable component in a vehicle - Google Patents

Abstract

The present invention relates to a method for pre-charging a first rechargeable component (C1) in a vehicle (100), said first rechargeable component (C1) being pre-charged by applying a voltage to said first rechargeable component (C1), said vehicle (100) comprising at least one electrical machine (110) being arranged to be connected to a first power supply path, said first rechargeable component (C1) being subjected to a voltage (VDC) of said first power supply path. The method includes, when said first rechargeable component (C1) is to be pre-charged:charging said first rechargeable component (C1) by applying a voltage over said first rechargeable component (C1) by means of said electrical machine (110).

Description

lO METHOD AND SYSTEM FOR PRE-CHARGING A RECHARGEABLE COMPONENT INA VEHICLE Field of the invention The present invention relates to vehicles, and in particularto a method and system for pre-charging rechargeablecomponents in an electrical system of the vehicle. The presentinvention also relates to a vehicle, as well as a computerprogram and a computer program product that implement the method according to the invention.Background of the invention With regard to vehicles in general, and at least to someextent heavy/commercial vehicles such as trucks, buses and thelike, there is constantly ongoing research and developmentwith regard to increasing fuel efficiency and reducing exhaust emissions.

This is often at least partly due to growing governmentalconcern in pollution and air quality, e.g. in urban areas,which has also led to the adoption of various emission standards and rules in many jurisdictions.

Apart from governmental concern, one of the main expensesassociated with vehicle operation is consumption of fuel forpropulsion of the vehicle. The degree of utilization of heavyvehicles is often high, and with its associated fuelconsumption, the cost of fuel can affect the profitability of the owner of the vehicle to a great extent.

In view of this, and in view of the fact that transport ofgoods on roads is expected to continuously increase,alternatives to conventional combustion engine technology are increasingly being considered. lO For example, electric vehicles and hybrid-electrical vehiclesare undergoing extensive research and development. Thesevehicles often include an electrical machine, where theelectrical machine is controlled by means of an inverterdrive. The inverter drive comprises switching means, e.g. inthe form of transistors, to, by means of suitable switching,generate an AC voltage from a DC link/bus voltage to besupplied to the electrical machine. This allows e.g. amplitudeand frequency of the terminal voltage of the stator phasewindings to be controlled and thereby also the work producedby and rotational speed of the electrical machine. Solutionsof this kind often include one or more capacitors, e.g. for stabilising the DC link voltage.

These capacitors, and other components as the case may be, areoften directly connected to a power source, such as e.g. anenergy storage, where pre-charging of the component isrequired when the component is connected to the power sourcefrom an uncharged state to reduce the risk of component damage.Summary of the invention It is an object of the present invention to provide a methodand system that allows for pre-charging of rechargeablecomponents in a manner that reduces need for pre-chargingcircuitry. This object is achieved by a method according to claim l.

According to the present invention, it is provided a methodfor pre-charging a first rechargeable component in a vehicle,said first rechargeable component being pre-charged byapplying a voltage to said first rechargeable component, saidvehicle comprising at least one electrical machine being arranged to be connected to a first power supply path, said lO first rechargeable component being subjected to a voltage ofsaid first power supply path. The method includes, when said first rechargeable component is to be pre-charged: - charging said first rechargeable component by applying avoltage over said first rechargeable component by means of said electrical machine.

As was mentioned above, electrical components may require apre-charge when starting up a system to avoid componentdamage. This can, for example, be the case in powerelectronics systems where high power supply voltages are used.For example, if an uncharged capacitor connected in parallelto a power source is subjected to voltage of the power source,the resulting current may damage the component. For thisreason, pre-charging circuits are often used, where, e.g.,sensitive components such as capacitors are pre-charged bylimiting the charging current when a high voltage is applied.This can, for example, be accomplished by the use of pre-charging circuits of a kind where the power source isconnected to the component to be charged via a resistorlimiting the current. When the component being charged hasbeen charged to some suitable extent, e.g. when the voltageover a capacitor has reached the power supply voltage or someother suitable voltage where the risk of damaging thecomponent is limited, the pre-charging circuit can be by-passed and the capacitor be connected in parallel to the power SOUICG .

Pre-charging circuits of this kind consequently have theadvantage that the initial current that electrical componentsare subjected to when a voltage is applied can be limited to adesired extent. This, however, is obtained at the expense ofadditional components, such as, e.g., additional contactors, resistors, additional wiring etc. The present invention lO provides an alternative solution for providing pre-charging ofcomponents where high initial currents can be harmful. Theinvention relates to vehicles, and in particular to systems inwhich an electrical machine is connectable to a power sourcevia a first power supply path, and where one or morecomponents requiring a pre-charge when being subjected to thepower supply and/or voltage of the power supply path are present.

According to the invention, this is accomplished by a solutionwhere pre-charging is performed by means of the electricalmachine. In general, when a rotor of an electrical machine isrotated, a voltage is induced in the stator windings, theinduced voltage being substantially proportional to therotational speed of the rotor. According to the invention, theinduced voltage is used to pre-charge the one or morecomponents for which pre-charging is required, and since thevoltage is proportional to the rotational speed of the rotor,the voltage can be e.g. successively increased by increasingthe rotational speed of the rotor. In this way capacitors, forexample, can be charged from a substantially uncharged state.The inductance of the stator winding will further “resist”transient current changes, and hence the“infinite”/high/harmful initial charging current will neveroccur. The electrical machine can, for example, consist of a permanent magnet synchronous three-phase machine.

The rotation of the electrical machine can, for example, beaccomplished by any suitable means of rotation of the rotor.For example, the electrical machine can be connectable to anoutput shaft of a combustion engine, in which case therotation can be accomplished by the aid of the combustionengine. Alternatively, the electrical machine can be arranged to be rotated by means of drive wheels of the vehicle, so that lO rotation can be accomplished at least when the vehicle is inmotion. According to one embodiment a starter motor/alternator can be used.

The present invention, consequently, provides a solution thatallows for charging of e.g. capacitors in a manner thatprohibits harmful initial currents. Furthermore, electricalmachines, at least with regard to vehicle propulsion, areoften arranged to be controlled by a drive system, such as aninverter drive system, in order to provide for rotationalspeed and torque control by controlling frequency and/orvoltage and/or phase of the stator winding voltage, theelectrical machine e.g. being a three phase machine. Suchdrives commonly include a switching arrangement forcontrolling frequency and/or phase and/or ßmplitude of astator terminal voltage of said electrical machine, andthereby also torque produced by said electrical machine.According to one embodiment these switching means are used tocontrolling the amplitude of the voltage being applied to said first rechargeable component.

According to one embodiment, the vehicle is a parallel hybridvehicle. According to one embodiment the vehicle is an electric vehicle.

Further characteristics of the present invention andadvantages thereof are indicated in the detailed descriptionof exemplary embodiments set out below and the attached drawings.Brief description of the drawings Fig. lA illustrates a power train of an exemplary hybrid electric vehicle; Fig. lB illustrates an example of a control unit in a vehicle control system; Fig. 2 illustrates the hybrid portion of the hybrid electric vehicle of fig. 1A more in detail;Fig. 3A-B illustrates a prior art pre-charging arrangement; Fig. 4 illustrates an exemplary method according to the present invention.Detailed description of exemplary embodiments The present invention will be exemplified in the following fora parallel hybrid vehicle. The invention, however, isapplicable for any hybrid electrical vehicle. For example, theinvention is applicable for parallel hybrid vehicles andseries hybrid vehicles. Further, for example, the invention isapplicable for hybrid vehicles having a plurality ofelectrical machines, where these, e.g. can be interconnected,directly and/or by means of transmission elements, such ase.g. planetary gears. The invention is applicable for anyelectric hybrid vehicle having one or more planetary gears,and also for power-split hybrid vehicles and series-parallelhybrid vehicles. The invention is also applicable for electric vehicles.

Fig. 1A schematically depicts a power train of an exemplaryhybrid electric vehicle 100. The vehicle 100 in fig. 1A is aparallel hybrid vehicle 100. The power train of the parallelhybrid vehicle in Fig. 1A comprises a combustion engine 101which, in a conventional manner, is connected, via an outputshaft of the engine 101, to a gearbox 103 via a clutch 106.The engine 101 is controlled by the vehicle's control systemvia a control unit 115. The clutch 106, which, for example,can be an automatically operated clutch, and the gearbox 103are also controlled by the vehicle's control system by means of a control unit 116.

The vehicle also includes a hybrid portion with an electricalmachine 110, which is connected to the input shaft 109 of thegearbox 103, downstream of the clutch 106, so that the gearboxinput shaft 109 can be driven by the electrical machine 110also when the clutch 106 is open. Thereby, the parallel hybridvehicle 100 can provide force to drive wheels 113, 114 fromtwo separate power sources simultaneously, i.e. both from thecombustion engine 101 and from the electrical machine 110.Alternatively, the vehicle may be propelled by one powersource at a time, i.e. either by the combustion engine 101 orthe electrical machine 110. The combustion engine 101 can also be arranged to apply a power to the electrical machine 110.

The hybrid portion also comprises further components. Fig. 1Adepicts part of these components, and shows the electricalmachine 110, an inverter drive 119 for controlling theelectrical machine 110, a power source, such as an energystorage, e.g. consisting of one or more batteries 111 and ahybrid control unit 112 which controls functions of the hybrid portion.

As indicated above, the functions of a vehicle are, ingeneral, controlled by a number of control units, and controlsystems in vehicles of the disclosed kind generally comprise acommunication bus system consisting of one or morecommunication buses for connecting a number of electroniccontrol units (ECUs), or controllers, to various components onboard the vehicle. Such a control system may comprise a largenumber of control units, and the control of a specific function may be divided between two or more of them.

For the sake of simplicity, Fig. 1A depicts only control units112, 115-116 but vehicles 100 of the illustrated kind areoften provided with significantly more control units, as one skilled in the art will appreciate. Control units 112, 115-116 can communicate with one another via said communication bus system, partly indicated by interconnecting lines in fig. 1A.

The present invention can be implemented in any suitablecontrol unit, and in the illustrated example the invention isimplemented in control unit 112 for controlling the hybriddrive portion of the vehicle. The invention may, however, alsobe implemented in any other suitable control unit. Pre-charging according to the present invention will usuallydepend on signals being received from other control unitsand/or vehicle components, and it is generally the case thatcontrol units of the disclosed type are normally adapted toreceive sensor signals from various parts of the vehicle 100.Control units of the illustrated type are also usually adaptedto deliver control signals to various parts and components ofthe vehicle. The control unit 112 will, for example, apartfrom other control of the hybrid drive system provide controlsignals for controlling one or more switches forconnecting/disconnecting the power source 111 to the electrical machine/inverter drive.

Control of this kind is often accomplished by programmedinstructions. The programmed instructions typically consist ofa computer program which, when it is executed in a computer orcontrol unit, causes the computer/control unit to exercise thedesired control, such as method steps according to the presentinvention. The computer program usually constitutes a part ofa computer program product, wherein said computer programproduct comprises a suitable storage medium 121 (see Fig. IB)with the computer program 126 stored on said storage medium121. The computer program can be stored in a non-volatilemanner on said storage medium. The digital storage medium 121can, for example, consist of any of the group comprising: ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), Flash memory, EEPROM (ElectricallyErasable PROM), a hard disk unit etc, and be arranged in or inconnection with the control unit, whereupon the computerprogram is executed by the control unit. The behaviour of thevehicle in a specific situation can thus be adapted by modifying the instructions of the computer program.

An exemplary control unit (the control unit 112) is shownschematically in Fig. 1B, wherein the control unit cancomprise a processing unit 120, which can consist of, forexample, any suitable type of processor or microcomputer, suchas a circuit for digital signal processing (Digital SignalProcessor, DSP) or a circuit with a predetermined specificfunction (Application Specific Integrated Circuit, ASIC). Theprocessing unit 120 is connected to a memory unit 121, whichprovides the processing unit 120, with e.g. the stored programcode 126 and/or the stored data that the processing unit 120requires to be able to perform calculations. The processingunit 120 is also arranged so as to store partial or final results of calculations in the memory unit 121.

Furthermore, the control unit 112 is equipped with devices122, 123, 124, 125 for receiving and transmitting input andoutput signals, respectively. These input and output signalscan comprise waveforms, pulses or other attributes that thedevices 122, 125 for receiving input signals can detect asinformation for processing by the processing unit 120. Thedevices 123, 124 for transmitting output signals are arrangedso as to convert calculation results from the processing unit120 into output signals for transfer to other parts of thevehicle control system and/or the component(s) for which thesignals are intended. Each and every one of the connections tothe devices for receiving and transmitting respective input and output signals can consist of one or more of a cable; a data bus, such as a CAN bus (Controller Area Network bus), aMOST bus (Media Oriented Systems Transport) or any other bus configuration, or of a wireless connection.

Fig. 2 discloses the power electronics portion of fig. 1A morein detail. In the current example, and as is generally thecase, the power source for providing power to the electricalmachine is a direct current power supply of relatively highvoltage, e.g. in the order of 300-1000 V. The power source111, such as a battery pack or other suitable power source, isarranged to be selectively connectable to the electricalmachine 110 by means of a pair of switches 205. The circuitryconnecting the power source 111 and electrical machine 110forms a power supply path, and the power source 111 isconnected to the electrical machine 110 via an inverter drive 119.

Electrical machines 110 of the disclosed kind are oftenarranged to be torque and/or speed controlled by means of aninverter drive system where inverter drives in general allowfor rotational speed and torque control of the electricalmachine by varying frequency and/or voltage and/or phase ofthe voltage being fed to the stator winding terminals.According to the disclosed example, the electrical machine 110is a three phase machine, hence having three phase windings,each phase voltage being controlled by associated switching means of the inverter drive 119. This is explained below.

There exist various examples of inverter drives, and thepresent invention is suitable for use with any inverter drivesolution providing a power path from the electrical machine ina direction towards the inverter drive. The electrical machine110 of the present example is a permanent magnet synchronousthree-phase machine. However, any suitable electrical machine can be used, as long as a voltage is induced when rotating the 11 rotor of the electrical machine. Where required any suitableassociated inverter drives can be used, where various kinds of inverter drives often exist for a particular kind of machine.

Inverter drives, in general, use a DC link voltage, also knownas DC bus voltage, from which AC voltages of suitablefrequency and amplitude are formed. One or more capacitors areoften used to smoothen the DC link voltage and/or enhancevoltage stiffness of the DC link voltage. The DC link voltageis affected both by power drawn by the electrical machine andalso by a rectified voltage resulting from the electricalmachine, where this rectified voltage results in a voltageripple, as is known per se. The above functionality is atleast in part provided by capacitor Cl in fig. 2. When asystem of the kind shown in fig. 2 is to be started in asituation where the capacitor Cl is essentially uncharged, thepower source 111 cannot be directly connected to the capacitorCl by closing the switch pair 205. As is known, an unchargedcapacitor acts as a short-circuit at the instant a voltage isapplied which by definition, in theory, would result in aninfinite initial current, and in practice a current that,likely damages or destroys the capacitor Cl. For this reason,pre-charging circuits are usually used. Prior art pre-charging is disclosed in fig. 3A-B.

Fig. 3A-B shows a system similar to the system of fig. 2, withthe difference that the switch pair 205 in fig. 2 is replacedby pre-charging circuitry 305 (shown more in detail in fig.3B). When the power source 311 is to be connected to inverter319 in a situation where capacitor C is uncharged, switches306, 307 are first closed, thereby allowing a current to flow from power source 311 to capacitor C via resistors R1, R2.

The function of the pre-charging circuitry is to reduce or minimize the peak current from the power source at the moment l0 l2 of connection by reducing dV/dT over the capacitor Cl. The useof resistors Rl, R2 ensure that the capacitor voltage willrise slowly and controllably with a maximum initial currentthat is not harmful. The resistors Rl, R2 thus ensures thatthe capacitor C is charged by means of a limited and suitablecharging current. When the capacitor C has been charged to asuitable extent, e.g. when the voltage over the capacitor Chas reached some suitable voltage, such as some suitablepercentage of the voltage of the power source 3ll, e.g. 80-l00% of this voltage, the switches 308, 309 are closed so thatcapacitor C is connected directly in parallel to the power source lll.

Systems of the kind disclosed in fig. 3A-B, consequently,require dedicated circuitry to protect components whenstarting up the system. According to the present invention, asis shown in fig. 2, such additional circuitry can be omittedwhile still ensuring proper precaution with regard to charging currents when pre-charging capacitor Cl.

An exemplary method 400 according to the invention is shown infig. 4, which exemplifies a method for connecting the power source lll to the inverter drive ll9.

In step 40l it is determined whether the power supply path forconnecting the power source lll to the electrical machine ll0is to be closed. The method remains in step 40l for as long asthis is not the case. When it is determined that the powersupply path is to be closed, e.g. when the vehicle l00 isstarted and the power source lll is to be used to power theelectrical machine llO, or when the power source lll is to becharged e.g. by regenerative braking using the electrical machine llO, the method continues to step 402, where it is determined whether pre-charging of the system is required. 13 According to one embodiment, pre-charging is performed whenthe DC link voltage VM is below a first voltage limit Vmn,which e.g. can be a voltage at which it is determined that noharmful currents occur upon closing of the switch 205. If thevoltage is above the limit Vmn, the method continues to step403 where switch 205 is closed, the power source 110 therebybeing connected to the electrical machine 111. When thevoltage is below said limit Vhm, the method continues to step404 for pre-charging the capacitor Cl. According to thepresent invention, this is performed by inducing a voltage bymeans of the electrical machine 110. As was explained above,a rotation of the rotor of the electrical machine 110 willinduce a voltage in the stator winding (a three-phase voltagewill be induced by the phase windings in a three-phasemachine) which will be proportional to the rotational speed of the electrical machine 110.

Inverter drives of the kind disclosed in fig. 2, and inverterdrives in general and with regard to hybrid vehicles inparticular, allows power to flow in both directions throughthe inverter. This is made possible by diodes 231-236 beingarranged anti-parallel to transistors 221-226. The diodes 231-236 will rectify the voltage induced by the stator winding,and provide a rectified voltage exhibiting some ripple on theDC link, the rectified voltage, when transistors 221-226 areturned off, having an amplitude being proportional to the rotational speed of the electrical machine 110.

According to one embodiment, the (rotor of the) electricalmachine 110 is rotated in step 404 to induce a voltage on theDC link via the rectifying diodes 231-236, which thereby willcharge the capacitor C1 to a capacitor voltage in the order ofthe induced voltage, where the current will be limited to the current induced in the stator windings. When the rotor is 14 rotated such that substantially no torque is produced theinduced current will be small, and hence the capacitor willnot be subjected to harmful currents. The voltage can becontrolled by speed of rotation of the electrical machine,which in turn can be controlled e.g. by controlling the rotational speed of the combustion engine 101.

In step 405 it is determined whether the DC link voltage hasreached desired level Vhm, e.g. a voltage in the order of 80-100% of the voltage of the power source 111, and rotation ofthe electrical machine continues for as long as this is notthe case. When the DC link voltage equals or exceeds thedesired level Vhm the method continues to step 406 where theswitch 205 is closed without the risk for damaging components.

The method is then ended in step 407.

As mentioned, rotation of the electrical machine can beaccomplished e.g. by means of the combustion engine 101, forexample if the vehicle 100 is standing still. Alternatively,the electrical machine can be rotated by means of the vehicledrive wheels, where, in the present example, a suitablerotation speed can be obtained e.g. by controlling the gearratio of the gearbox 103. Furthermore, when the DC linkvoltage has reached some voltage level, it will be possible toactivate switching of the transistors, and according to oneembodiment the DC link voltage can be further controlled todesired level by suitable switching of the induced voltage using the transistors 221-226.

With regard to the inverter drive exemplified in fig. 2, aplurality of transistors 221-226, such as e.g. IGBT (InsulatedGate Bipolar Transistor) transistors, are used to generate asupply voltage at the stator terminals of the electricalmachine 110 my means of appropriate switching of the transistors. According to the disclosed example, three pairs of transistors, 221-222; 223-224; and 225-226, respectively,each provide a phase voltage of the three-phase voltage, eachphase-voltage having a controllable and variable frequency, voltage and phase by means of appropriate switching.

Inverter drives of the disclosed kind often uses Pulse WidthModulation (PWM) in order to accomplish the desired voltageand frequency, which means that the DC link voltage isswitched on and off at high frequency (e.g. 1-10 kHz switchingfrequency) by means of the transistors 221-226, the PWMpattern forming a pulse train mimicking a sine wave of desiredfrequency and amplitude, as is well known to the personskilled in the art. These transistors, consequently, can alsobe used to control the DC link voltage using the inducedvoltage. So far, the invention has been described for pre-charging of capacitor C1, but there may be further and/or other rechargeable components that require pre-charging.

For example, vehicles usually comprise a plurality of directcurrent DC applications and the DC power for powering theelectric motor can be used also for powering such othercomponents. For example, the voltage used for powering theelectric motor can be converted to, e.g., 24V, (12 V or 48V)for conventional 24 V (12V, 48V) applications, such as cooling fans or conventional vehicle electronics in general.

This is illustrated in fig. 2 by AUX power electronics 202-204, where these often are provided with capacitors as well,which capacitors often are connected in parallel to the powersupply path and consequently also can require and be pre- charged using the present invention.

Consequently, the present invention provides for a method forpre-charging sensitive components without the need for pre- charging circuitry. 16 Further, hitherto the invention has been described for asituation where the power source is to be connected from adisconnected state. The present invention, however can be usedalso in other situations, e.g. if the electrical machine is to be used for regenerative braking.

The electrical machine 111 can, in general, be used to applybraking powers, which can be used for charging e.g. the powersource 111, but occasionally the power source can be fullycharged, or charging otherwise be undesired. Still it can bedesired to perform regenerative braking, e.g. in order topower auxiliary equipment or simply to dissipate theregenerated power in a high-power resistor. Also, the powerwill be transported using the power supply path and hencesubject capacitors to high voltages. In order to do this itmust be possible to control the electrical machine, and hencethe inverter must be in operation. This however, is onlypossible if the DC link voltage is high enough to allowoperation of the transistors, and the present invention can beused also in such situations to pre-charge the capacitor C1,and other capacitors being connected to the DC link, first bythe induced voltage alone and the also using switching of thetransistors, thereby avoiding the need for connecting thepower source 111 altogether in situations where e.g. power is to be dissipated using e.g. a power resistor.

Finally, the technology disclosed above can be also be used tocontrol the voltage when switching between different powersupply paths for powering an electrical machine, where thepower supply paths have different power supply voltages. Thisis further disclosed in the parallel Swedish patentapplication no. 145XXXx-X, with the title “METHOD AND SYSTEMFOR SWITCHING FROM A FIRST POWER SUPPLY PATH TO A SECOND POWERSUPPLY PATH”. This application relates to a method for 17 switching power supply path of at least one electricalmachine, where the electrical machine is arranged to beselectively power supplied by a first power supply path and asecond power supply path, respectively, by alternately openingand closing said power supply paths. The power supply pathsare arranged to connect a power supply source to a firstconnection terminal means of the electrical machine. Thedisclosed method includes, when switching from the first power supply path to the second power supply path:- opening the first power supply path; - by means of said electrical machine, controlling a terminalvoltage of said first connection terminal means tosubstantially a power supply voltage of the second power supply path, and;- closing said second power supply path.

Finally, it should be understood that the present invention isnot limited to the embodiments described above, but relates toand incorporates all embodiments within the scope of the appended independent claims.

Claims (1)

1. 8 Claims 1. Qi; 473. .Method according to claim 1, M +1a A -wfifi vfJäfifw +-0 LJ. pil LA. L/L\./\./ J_L/L_|_J.J.\j L, Method for pre-charging a first rechargeable component (Cl) in a vehicle (100), said first rechargeable (Cl) being pre-charged by applying a voltage to (Cl), componentsaid vehicle (110) said first rechargeable component (100) comprising at least one electrical machinebeing arranged to be connected to a first power supply said first rechargeable component (Cl) being(Vnc) characterised in that said method includes, path, subjected to a voltage of said first power supply path, when said first rechargeable component (Cl) is to be pre- charged: - charging said first rechargeable component (Cl) by applying a voltage over said first rechargeable component (Cl) by means of said electrical machine (110), and - pre-charging said first rechargeable component (Cl) by means of said electrical machine (110) when said first rechargeable component (Cl) is in an essentiallyuncharged state¿said electrical machine (110) being a permanent magnet synchronous three-phase machine. said electrical machine (110) being arranged to be connected to a first power source (111) by means of said first power supply path, the method further including:- pre-charging said first rechargeable component (Cl) when said first power source (111) is disconnected from said first rechargeable component (Cl). ') -uvvw 'I -v~i J. J. I m1 fwy/.LL/LJ. LL Method according to any one of the claims 1-å or 2, further including: 19 - charging said first rechargeable component (C1) bymeans of a voltage being induced by rotation of a rotor of said electrical machine (110). ä74. Method according to claim 4â, further including:- said induced voltage being induced in a stator windingof said electrical machine (110) by rotation of said rotor of said electrical machine (110). ê75. Method according to any of the claims 1-ëí, furtherincluding, when pre-charging said first rechargeablecomponent:- controlling rotation of a rotor of said electrical machine (110). 476. Method according to claim êë, said vehicle (100)including means for rotating said rotor of saidelectrical machine (110), further including: - controlling rotation of a rotor of said electricalmachine (110) using said means for rotating said rotor of said electrical machine. 877. Method according to claim 4§, said means for rotatingsaid rotor of said electrical machine (110) being a combustion engine. 978. Method according to any one of the preceding claims,further including, during pre-charging of said firstrechargeable component (C1): - successively increasing the voltage applied over said first rechargeable component (C1). 1079. Method according to any one of the preceding claims,further including, during pre-charging of said firstrechargeable component (C1): - increasing the voltage applied over said first rechargeable component (Cl) by increasing the rotational speed of the rotor of said electrical machine (llO). ll7lQ;_Method according to any one of the claims l-låg, saidvehicle further including an inverter drive (ll9) forcontrolling frequency and/or phase and/or amplitude of astator terminal voltage of said electrical machine (llO),said inverter drive further including means (231-236) forrectifying an AC voltage induced by said electricalmachine (llO), said method further including:- pre-charging said first electrical component (Cl) using said rectified AC voltage. l%7ll;_Method according to claim lllg, said inverter drive(ll9) further including switching means (22l-226) forvarying frequency and/or voltage of an AC voltage forcontrolling said electrical machine, further including:- controlling the amplitude of the voltage being appliedto said first rechargeable component (Cl) using said switching means (22l-226). l%Tl2. Method according to any one of the preceding claims, said first rechargeable component being a capacitor (Cl). l4Tl3. Method according to claim ll-lO or lêll, said firstrechargeable component being a DC link capacitor forstabilising the DC link voltage of said inverter drive (ll9). lä7lí;_Method according to any one of the preceding claims,further including, when pre-charging said firstrechargeable component:- controlling the current said first electrical component(Cl) being subjected to by controlling the power delivered by said electrical machine (llO). 21 1é11§;_Method according to any one of the preceding claims,said method further including, when said electricalmachine (110) is to be connected to a first power source(111) for providing electrical power to said electricalmachine (110):- controlling the voltage of said first component (Cl) toat least 80% of the voltage of said first power source (111) prior to connecting said first power source (111). 11116. Method according to any one of the preceding claims,said electrical machine being arranged to provide apropelling torque and or a brake torque to at least one drive wheel of said vehicle. 1%117. Computer program comprising program code that, whensaid program code is executed in a computer, causes saidcomputer to carry out the method according to any of claims 1-141§. 19118. Computer program product comprising a computer-readable medium and a computer program according to claim1811, wherein said computer program is contained in said computer-readable medium. 20712;_System for pre-charging a first rechargeable component (C1) in a vehicle (100), said firstrechargeable component (C1) being pre-charged by applyinga voltage to said first rechargeable component (C1), saidvehicle (100) comprising at least one electrical machine(110) being arranged to be connected to a first powersupply path, said first rechargeable component (C1) beingsubjected to a voltage (Vbc) of said first power supplypath, characterised in that said system includes, whensaid first rechargeable component (C1) is to be pre- charged: lO 22 - means for charging said first rechargeable component(Cl) by applying a voltage over said first rechargeablecomponent (Cl) by means of said electrical machine (llO),and - means for pre-charging said first rechargeablecomponent (Cl) by means of said electrical machine (llO)when said first rechargeable component (Cl) is in anessentially uncharged state¿ said electrical machine (llO) being a permanent magnet synchronous three-phase machine. %lT2O. Vehicle, characterised in that it comprises a system according to claim êêlâ.