SE543511C2 - A method for controlling operation of two belt driven alternators and an electric power generating system having two such alternators - Google Patents
A method for controlling operation of two belt driven alternators and an electric power generating system having two such alternatorsInfo
- Publication number
- SE543511C2 SE543511C2 SE1950862A SE1950862A SE543511C2 SE 543511 C2 SE543511 C2 SE 543511C2 SE 1950862 A SE1950862 A SE 1950862A SE 1950862 A SE1950862 A SE 1950862A SE 543511 C2 SE543511 C2 SE 543511C2
- Authority
- SE
- Sweden
- Prior art keywords
- alternators
- phase shift
- alternator
- voltage
- rotor
- Prior art date
Links
Classifications
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
- H02P9/14—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field
- H02P9/26—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices
- H02P9/30—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices using semiconductor devices
- H02P9/305—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices using semiconductor devices controlling voltage
- H02P9/307—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices using semiconductor devices controlling voltage more than one voltage output
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60R—VEHICLES, VEHICLE FITTINGS, OR VEHICLE PARTS, NOT OTHERWISE PROVIDED FOR
- B60R16/00—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for
- B60R16/02—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements
- B60R16/03—Electric or fluid circuits specially adapted for vehicles and not otherwise provided for; Arrangement of elements of electric or fluid circuits specially adapted for vehicles and not otherwise provided for electric constitutive elements for supply of electrical power to vehicle subsystems or for
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/14—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle
- H02J7/143—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle with multiple generators
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
- H02P9/06—Control effected upon clutch or other mechanical power transmission means and dependent upon electric output value of the generator
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
- H02P9/14—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field
- H02P9/26—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices
- H02P9/30—Arrangements for controlling electric generators for the purpose of obtaining a desired output by variation of field using discharge tubes or semiconductor devices using semiconductor devices
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P9/00—Arrangements for controlling electric generators for the purpose of obtaining a desired output
- H02P9/48—Arrangements for obtaining a constant output value at varying speed of the generator, e.g. on vehicle
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J2310/00—The network for supplying or distributing electric power characterised by its spatial reach or by the load
- H02J2310/40—The network being an on-board power network, i.e. within a vehicle
- H02J2310/46—The network being an on-board power network, i.e. within a vehicle for ICE-powered road vehicles
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J3/00—Circuit arrangements for ac mains or ac distribution networks
- H02J3/38—Arrangements for parallely feeding a single network by two or more generators, converters or transformers
- H02J3/40—Synchronising a generator for connection to a network or to another generator
- H02J3/44—Synchronising a generator for connection to a network or to another generator with means for ensuring correct phase sequence
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
- H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
- H02J7/14—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries for charging batteries from dynamo-electric generators driven at varying speed, e.g. on vehicle
- H02J7/16—Regulation of the charging current or voltage by variation of field
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P5/00—Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors
- H02P5/46—Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors for speed regulation of two or more dynamo-electric motors in relation to one another
-
- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P5/00—Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors
- H02P5/74—Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors controlling two or more ac dynamo-electric motors
- H02P5/747—Arrangements specially adapted for regulating or controlling the speed or torque of two or more electric motors controlling two or more ac dynamo-electric motors mechanically coupled by gearing
Landscapes
- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Mechanical Engineering (AREA)
- Control Of Eletrric Generators (AREA)
Abstract
A method for controlling operation of two alternators (2, 3) each having a rotor (4, 5) driven by a belt (6) in common to the alternators and pulled by an engine (7), in which the outputs of the alternators are connected to a rectifier (11) for DC feeding of at least one electric battery (12), includes the step of determining the phase shift of AC voltages generated by the two alternators. The phase shift determined is compared with a target phase shift resulting in a minimum of voltage ripple on DC lines (18) from the rectifier. The load of the respective alternator and thereby the relation of a slip of the belt of one alternator with respect to the other alternator is individually controlled by controlling rotor flux for changing the phase shift towards the target phase shift and maintaining it there when reached.
Description
AND BACKGROUNDART The present invention relates to a method for controlling theoperation of two alternators each having a rotor driven by a belt incommon to the alternators and pulled by an engine, in which theoutputs of the alternators are connected to a rectifier for DCfeeding of at least one electric battery, as well as an electric powergenerating system according to the preamble of the appended independent claim directed to such a system.
The invention is directed to operation control of such alternators,normally called twin alternators, driven by an engine in any type ofelectric power generating systems, but it is particularly directed tosuch a system arranged in heavy vehicles, such as wheeled heavyvehicles, especially in the form of buses and trucks, which is thereason for below discussing the invention for such use forilluminating the invention but not restricting it thereto.
Alternators in for instance vehicle applications produce aconsiderably ripple voltage of the DC voltage fed to electricbatteries. This ripple voltage is inherent for any rectifier design.The ripple can be altered but not avoided. For a theoretical idealthree phase alternator the voltage ripple has a frequency of sixtimes the rotational speed multiplied with the number of pole pairs.ln almost all cases the two alternators run at the same speed and therefor the ripple voltage of the two alternators have the same frequency. Due to small tolerances in for instance the diametersof pullies driven by the belt for driving the rotors of the alternatorsthe phase shift between the two ripple voltages changes slowlyover time. Thus, it does not matter that the desired phase shift,which is the phase shift occurring when the positive peak of oneripple voltage occurs at the same time as a negative peak of theother ripple voltage, is initially set for the two alternators, sincethis phase shift will due to belt slip and other said tolerances beleft after a short time. This means that the worst case where both ripple voltages add up to a maximum is reached repeatedly. ln applications with such so-called twin alternators the totalvoltage ripple of the DC voltage to be fed to said at least oneelectric battery might exceed tolerable limits and can cause noiseand malfunctions or reduce the life time of components. Thus, thevoltage ripple causes additional losses and noise compared to thecase of an ideal DC voltage. Furthermore, such two alternatorsapplications run typically on much higher loads compared to singlealternator applications, but the batteries and the capacitance ofthe control units remain the same. This means that the ratiobetween the actual alternator output and the filter capacitance isless favourable for the two alternators case and result in higher ripple voltages.
SUMMARY OF THE INVENTION The object of the present invention is to provide a method and anelectric power generating system of the types defined in theintroduction being improved in at least some aspect with respect to such methods and systems already known.
This object is with respect to the method obtained by providingsuch a method with the features listed in the characterizing part of appended patent claim 1.
Accordingly, the phase shift of the AC voltages generated by thetwo alternators is determined and compared with a target phaseshift resulting in a minimum of voltage ripple on DC lines from therectifier to the electric battery, i.e. when the positive peak of oneripple voltage from one of the alternators occurs at the same timeas a negative peak of a ripple voltage from the other alternator.The load of the respective alternators and thereby the relation ofa slip of said belt of one alternator with respect to that of the otheralternator is individually controlled by controlling the rotor flux ofthe alternators to change the phase shift towards the target phaseshift and maintaining it there when reached. By controlling the slipfor two belt driven alternators individually the phase shift betweenthe individual voltage ripples can be controlled and kept close toan optimum, and since the slip is dependent on the alternator loada load shift between two alternators will increase the slip on onealternator and in turn reduce it on the other. Different slip causesdifferent speed on the alternators and thereby over time a changein the phase shift. As soon as said target phase shift desired isachieved the load shared between the alternators can be balancedto maintain this phase shift by ensuring that the rotors of thealternators rotate with the same speed. Thus, a phase lock of the alternators is then obtained.
According to an embodiment of the invention the individually controlling of the loads is carried out by controlling the magnitude of the rotor current in the respective alternator rotor. The loadshare resulting in a fixed phase shift of the two alternators mayefficiently be balanced in this way to maintain the phase shift desued.
According to another embodiment of the invention said phase shiftis directly determined by measuring the AC voltage on the outputof each alternator and comparing this voltage of one alternatorwith the voltage of the other. The phase shift so measured will thenbe compared with a target phase shift resulting in an minimum ofvoltage ripple, which for instance for 2-pole three phasealternators is 30° + n x 60° with n=O.1, 2, so that the targetphase shift will then be obtained when a phase shift of 30°, 90°, 150°, 210° and so on of said AC voltages measured is obtained.
According to another embodiment of the invention the steps a) andb) of determining and comparing are carried out by measuring aDC voltage and by that the ripple thereof on DC lines to saidelectric battery and introducing the result of this measurement ina mathematical model for calculating the need of phase shiftchange and then also the load to be applied on each alternator forobtaining said target phase shift. This is an alternative way ofreaching and once reached maintaining the target phase shiftresulting in a minimum of voltage ripple of the DC voltage to the electric battery.
The object of the invention is with respect to the electric powergenerating system obtained by providing such a system with thefeatures listed in the characterizing part of the independent system claim. Thus, this system comprises an arrangement configured to determine the phase shift of AC voltages generated by the twoalternators, comparing means configured to compare said phaseshift determined with a target phase shift resulting in a minimumof voltage ripple on DC lines from the rectifier to the electricbattery, and a member configured to, based on the result of thiscomparison, control load of the respective alternator and therebythe relation of a slip of the belt of one alternator with respect tothat of the other alternator by controlling the rotor flux so as tochange the phase shift towards the target phase shift andmaintaining it there when reached. The advantages of such anelectric power generating system and the embodiments thereofdefined in the dependent system claims appear clearly from theabove discussion of the method according to the invention. Apreferred application of such an electric power generating system is in a motor vehicle.The invention also relates to a computer program, a computerprogram product, an electronic control unit and a motor vehicle according to the appended claims directed thereto.
Further advantages as well as advantageous features of the invention will appear from the description following below.
BRIEF DESCRIPTION OF THE DRAWINGS With reference to the appended drawings, below follows a specific description of embodiments of the invention cited as examples. ln the drawings: Fig 1 Fig 2 Fig 3 Fig 4 Fig 5 Fig 6 Fig 7 is a schematic view illustrating how two alternators arearranged in a motor vehicle electric power generating system to which the present invention is directed, is a graph of the alternating voltage of one phase of twoalternators in such a system and a DC voltage outputresulting therefrom versus angle in radians for the worst case phase shift of the two alternators, is a graph corresponding to Fig 2 for the case of anoptimized phase shift, i.e. a said target phase shift of the two alternators, is a simplified view illustrating an electric powergenerating system used for carrying out a method according to a first embodiment of the invention, is a view corresponding to that according to Fig 4 of anelectric power generating system according to a secondembodiment of the invention used to carry out a method according to a second embodiment of the invention, is a flow chart illustrating the steps carried out in amethod according to the first embodiment of the invenüon,and illustrates schematically an electronic control unit according to the invention.
DETAILED DESCRIPTION OF EMBODIMENTS OF THEINVENTION Fig 1 illustrates schematically parts of an electric power generatingsystem of the type to which the present invention is directedarranged in a motor vehicle 1 and comprising two alternators 2, 3each having a rotor 4, 5 (very schematically indicated) driven by abelt 6 in common to the alternators. An engine 7 is configured topull the belt to rotate the rotors for generating electric power. Amember 8 is configured to control the load of the alternators in away to be described further below. The belt 6 will slip slightly onthe pullies 9, 10 of the two alternators and the magnitude of thisslip will be dependent upon the load applied on the alternators. lfthis slip is the same for both alternators the rotors thereof willrotate with the same speed. However, due to small tolerances infor instance pulley diameters and dynamical effects in the beltdrive the speed of the rotors of the two alternators will differ unless certain measures are taken.
The alternating voltages generated in the stator windings of thealternators is rectified by a rectifier 11 (see Figs 4 and 5) forfeeding a DC power to at least one electric battery 12 of thesystem. The rectifier produces a ripple voltage on the DC voltagefed to the electric battery, and this ripple voltage will be as smallas possible when for the phase shift of the AC voltages generatedby the two alternators the positive peak of one ripple voltageoccurs at the same time as a negative peak of the other ripplevoltage. ln that case both ripple voltages cancel each other almostcompletely. However, in the worst case both ripple voltages add up to a maximum, which is illustrated in Fig 2 in which there is no phase shift between the AC voltages, AC2 and ACs, of the twoalternators resulting in a DC output from the rectifier with aconsiderable ripple voltage. Fig 3 illustrates what happens whenthe phase shift is instead 30°, which here is an optimized phaseshift resulting in merely no DC ripple voltage. What is illustrated isthe case with 2-pole three phase alternators for which a phaseshift of 30° + n x 60° (n = 0.1, 2, 3,...) results in an optimized phaseshift.
Thus, it is a desire to obtain and keep the optimized phase shiftresulting in a minimum of DC voltage ripple as shown in Fig 3, andan electric power generating system according to the inventionaddresses this. A system according a first embodiment of theinvention is very schematically illustrated in Fig 4. The systemcomprises an arrangement 13 configured to determine the phaseshift of AC voltages generated by the two alternators 2, 3 and hasfor this sake means 14, 15 configured to measure the AC voltageon the output of each alternator and means 16 configured tocompare the voltage of one alternator with the voltage of the otherfor by that determining said phase shift. The control member 8includes means 17 configured to compare the phase shiftdetermined with a target phase shift resulting in a minimum ofvoltage ripple on the DC lines from the rectifier 11 to the electricbattery. The control member 8 is configured to, based on the resultof this comparison, control load of the respective alternator andthereby the relation of a slip of the belt 6 of one alternator withrespect to that of the other alternator by controlling their rotor flux,such as by controlling the magnitude of the rotor current in therespective alternator rotor, so as to change the phase shift towards said target phase shift and maintaining it there when reached.
When for instance in the case mentioned above a phase shift of140° is determined the control member will advantageously decideto change the phase shift to 150°, which is the optimum phase shiftclosest to 140°, by reducing or increasing the rotor flux in thealternators and by that changing the load thereof and the relationof the slips on their pullies. A change in the alternator load causesa change in the angle between the rotor flux and the stator voltage,which has to be considered when controlling the ripple voltages, since it offsets the slip induced phase shift.
Fig 5 illustrates schematically an electric power generating systemaccording to a second embodiment of the invention differing fromthat shown in Fig 4 by the fact that said arrangement comprisesvoltage measuring means 20 configured to measure a DC voltageand by that the ripple thereof on DC lines 18 to the electric battery12. The arrangement further comprises means 21 configured tointroduce the result of this measurement in a mathematical modeland to calculate the need of phase shift of the two alternators onthe basis of this measurement result and then also the load to beapplied on each alternator for obtaining said target phase shift.Such load orders are sent to the control member 8, which carriesout an individual control of the loads of the two alternatorsaccordingly. Information about the load so applied on therespective alternator is sent to the calculating means 21 forfeedback. Thus, the calculating means 21 calculates the loads tobe applied to the two alternators for obtaining and then alsomaintaining the target phase shift thereof resulting in a minimum of DC voltage ripple.
Fig 6 illustrates a flow chart of a method according to anembodiment of the present invention carried out for an electricpower generating system of the type illustrated in Fig 4. Themethod is started with a step S1 of measuring AC voltages onoutputs of both alternators followed by a step S2 of comparing thephase position of these AC voltages and determining their phaseshift. The phase shift so determined is then in a step Se, comparedwith a target phase shift. The load of the alternators is thenindividually controlled to change the phase shift towards the targetphase shift when not already there and maintaining it whenreached in a step S4. The step S1-Se, are continuously repeated forenabling step S4 and maintaining a phase shift resulting in aminimum of voltage ripple on DC lines from the rectifier to the electric battery.
Computer program code for implementing a method according tothe invention is with advantage included in a computer programwhich can be read into the internal memory of a computer, e.g. theinternal memory of an electronic control unit of a motor vehicle.Such a computer program is with advantage provided via acomputer program product comprising a data storage mediumwhich can be read by a computer and which has the computerprogram stored on it. Said data storage medium is for example anoptical data storage medium in the form of a CD ROM disc, a DVDdisc etc., a magnetic data storage medium in the form of a harddisc, a diskette, a cassette tape etc., or a flash memory or amemory of the ROM, PROM, EPROM or EEPROM type. Fig. 7unit 30 comprising an execution means 31, e.g. a central processor unit illustrates very schematically an electronic control (CPU), for execution of computer software. The execution means 11 31 communicates with a memory 32, e.g. of the RAM type, via adata bus 33. The control unit 30 comprises also a non-transitorydata storage medium 34, e.g. in the form of a flash memory or amemory of the ROM, PROM, EPROM or EEPROM type. Theexecution means 31 communicates with the data storage medium34 via the data bus 33. A computer program comprising computerprogram code for implementing a method according to theinvention, e.g. in accordance with the embodiment i||ustrated in Fig. 6, is stored on the data storage medium 34.
The invention is of course in no way restricted to the embodimentsdescribed above, since many possibilities for modifications thereofare likely to be obvious to one skilled in the art without having todeviate from the scope of invention defined in the appended claims.
Claims (14)
1. A method for controlling operation of two alternators (2, 3)each having a rotor (4, 5) driven by a belt (6) in common tothe alternators and pulled by an engine (7), the outputs of thealternators being connected to a rectifier (11) for DC feedingof at least one electric battery (12), characterized by a) determining the phase shift of AC voltages generated bythe two alternators (2, 3), b) comparing said phase shift determined with a target phaseshift resulting in a minimum of voltage ripple on DC lines(18) from said rectifier (11) to said electric battery (12),and while carrying out steps a) and b) c) individually controlling load of the respective alternator (2,3) and thereby the relation of a slip of said belt (6) of onealternator with respect to that of the other alternator bycontrolling their rotor flux so as to change said phase shifttowards said target phase shift and maintaining it there when reached.
2. A method according to claim 1, characterized in that theindividually controlling of the loads in step c) is carried out bycontrolling the magnitude of the rotor current in the respective alternator rotor (4, 5).
3. A method according to claim 1 or 2, characterized in that instep a) said phase shift is directly determined by measuring the AC voltage on the output of each alternator (2, 3) and 13 comparing this voltage of one alternator with the voltage ofthe other.
4. A method according to claim 1 or 2, characterized in thatsteps a) and b) are carried out by measuring a DC voltage andby that the ripple thereof on DC lines (18) to said electricbattery (12) and introducing the result of this measurement ina mathematical model for calculating the need of phase shiftchange and then also the load to be applied on each alternator (2, 3) for obtaining said target phase shift.
5. An electric power generating system comprising:o two alternators (2, 3) each having a rotor (4, 5) to bedriven by a belt (6) in common to the alternators,o an engine (7) configured to pull said belt (6) to rotatesaid rotors for generating electric power, ando a rectifier (11) connected to outputs of the alternators(2, 3) to produce a DC power to be fed to at least oneelectric battery (12) of the system,characterized in that the system further comprises anarrangement (13) configured to determine the phase shift ofAC voltages generated by the two alternators, comparingmeans (17) configured to compare said phase shiftdetermined with a target phase shift resulting in a minimum ofvoltage ripple on DC lines (18) from said rectifier to saidelectric battery, and a member (8) configured to, based on theresult of said comparison, control load of the respectivealternator (2, 3) and thereby the relation of a slip of said belt(6) of one alternator with respect to that of the other alternator by controlling their rotor flux so as to change said phase shift 14 towards said target phase shift and maintaining it there when reached.
6. A system according to claim 5, characterized in that saidmember (8) is configured to individually control the load of therespective alternator (2, 3) by controlling the magnitude of the rotor current in the respective alternator rotor (4, 5).
7. A system according to claim 5 or 6, characterized in that saidarrangement (13) comprises voltage measuring means (14,15) configured to measure the AC voltage on the output ofeach alternator (2, 3), and that the arrangement comprisesvoltage comparing means (16) configured to compare this voltage of one alternator with the voltage of the other.
8. A system according to claim 7, characterized in that saidalternators (2, 3) are three phase alternators and said voltagemeasuring means (14, 15) is configured to measure thevoltage of one and the same phase on the output of eachalternator to be compared with each other by said voltage comparing means (16).
9. A system according to claim 5 or 6, characterized in that saidarrangement comprises voltage measuring means (20)configured to measure a DC voltage and by the ripple thereofon DC lines (18) to a said electric battery (12), and that thearrangement comprises means (21) configured to introducethe result of this measurement in a mathematical model andto calculate the need of phase shift change of the two alternators on the basis of this measurement result and then
10.
11.
12.
13.
14. also the load to be applied on each alternator for obtaining said target phase shift. A system according to any of claims 5-9, characterized in that it is an electric power generating system of a motor vehicle (1)- A computer program comprising computer program code forcausing a computer to implement a method according to anyof claims 1-4 when the computer program is executed by a computer. A computer program product comprising a non-transitory datastorage medium which can be read by a computer and onwhich the program code of a computer program according to claim 11 is stored. An electronic control unit comprising an execution means(31), a memory (32) connected to the execution means and anon-transitory data storage medium (34) which is connectedto the execution means and on which the computer program code of a computer program according to claim 11 is stored. A motor vehicle, especially a wheeled heavy motor vehicle,such as a truck or a bus, characterized in that it is providedwith an electric power generating system according to any ofclaims 5-9 or an electronic control unit (30) according to claim13.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE1950862A SE543511C2 (en) | 2019-07-08 | 2019-07-08 | A method for controlling operation of two belt driven alternators and an electric power generating system having two such alternators |
| DE102020003612.0A DE102020003612A1 (en) | 2019-07-08 | 2020-06-17 | Method for controlling the operation of two belt-driven generators and an electrical power generation system with two such generators |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SE1950862A SE543511C2 (en) | 2019-07-08 | 2019-07-08 | A method for controlling operation of two belt driven alternators and an electric power generating system having two such alternators |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| SE1950862A1 SE1950862A1 (en) | 2021-01-09 |
| SE543511C2 true SE543511C2 (en) | 2021-03-16 |
Family
ID=74092476
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| SE1950862A SE543511C2 (en) | 2019-07-08 | 2019-07-08 | A method for controlling operation of two belt driven alternators and an electric power generating system having two such alternators |
Country Status (2)
| Country | Link |
|---|---|
| DE (1) | DE102020003612A1 (en) |
| SE (1) | SE543511C2 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE102021118787A1 (en) * | 2021-04-06 | 2022-10-06 | Bomag Gmbh | ROD TILLER WITH POWER SYSTEM, METHOD OF OPERATING A TILLER AND METHOD OF RETROFITTING A TILLER |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5723972A (en) * | 1995-12-29 | 1998-03-03 | Bartol; Luis E. | Fail-safe common control of multiple alternators electrically connected in tandem parallel for producing high current |
| US6201310B1 (en) * | 1999-04-01 | 2001-03-13 | Mitsubishi Denki Kabushiki Kaisha | Car power supply system |
| US20110175580A1 (en) * | 2010-01-20 | 2011-07-21 | Denso Corporation | Vehicle generator |
| US20150180393A1 (en) * | 2013-12-23 | 2015-06-25 | Generac Power Systems, Inc. | Method Of Controlling Multiple Parallel-Connected Generators |
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2019
- 2019-07-08 SE SE1950862A patent/SE543511C2/en unknown
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2020
- 2020-06-17 DE DE102020003612.0A patent/DE102020003612A1/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5723972A (en) * | 1995-12-29 | 1998-03-03 | Bartol; Luis E. | Fail-safe common control of multiple alternators electrically connected in tandem parallel for producing high current |
| US6201310B1 (en) * | 1999-04-01 | 2001-03-13 | Mitsubishi Denki Kabushiki Kaisha | Car power supply system |
| US20110175580A1 (en) * | 2010-01-20 | 2011-07-21 | Denso Corporation | Vehicle generator |
| US20150180393A1 (en) * | 2013-12-23 | 2015-06-25 | Generac Power Systems, Inc. | Method Of Controlling Multiple Parallel-Connected Generators |
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| Publication number | Publication date |
|---|---|
| SE1950862A1 (en) | 2021-01-09 |
| DE102020003612A1 (en) | 2021-01-14 |
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