WO1997006594A1 - Device comprising a generator and method for control of such a device - Google Patents
Device comprising a generator and method for control of such a device Download PDFInfo
- Publication number
- WO1997006594A1 WO1997006594A1 PCT/SE1996/000995 SE9600995W WO9706594A1 WO 1997006594 A1 WO1997006594 A1 WO 1997006594A1 SE 9600995 W SE9600995 W SE 9600995W WO 9706594 A1 WO9706594 A1 WO 9706594A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- generator
- temperature
- current
- regulator
- voltage
- Prior art date
Links
Classifications
-
- 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
- H02P9/02—Details
Definitions
- Device comprising a generator and method for control of such a device.
- the present invention relates to a device comprising a generator, according to the preamble of appended claim 1.
- the invention also relates to a method for control of such a device, in accordance with the preamble of appended claim 4.
- Such energy consumers may for example be lighting arrangements and electrical heating arrangements for windows, seat heating devices for front and rear seats and active damping devices (CCD devices).
- CCD devices active damping devices
- the problem regarding cooling is solved by arranging a fan on the rotor shaft of the generator.
- the fan is dimensioned so as to correspond to the maximum output power of the generator, as seen in relation to the cooling capacity.
- this manner of dimensioning the fan so as to withstand the worst operating conditions results in problems in the form of unwanted noise generated by the fan.
- the total losses of the generator increase, i.e. the coefficient of efficiency of the generator is decreased. The faster the generator rotates, the higher the noise and the higher the losses are generated due to the fan.
- the object of the invention is thus to provide an improved generator in which the losses in the form of heat can be dissipated in a satisfactory manner, while at the same time a lower sound level and a higher coefficient of efficiency of the generator can be obtained. Said object is accomplished by means of a device of the kind initially mentioned, the characterizing features of which will be apparent from subsequent claim 1, and by means of a method of the kind initially mentioned, the characterizing features of which will be apparent from subsequent claim 4.
- the temperature of the generator is detected. If the tempetature of the generator is higher than a predetermined maximum allowed temperature limit, the magnetizing current to the rotor of the generator can be limited to a level which corresponds to a heat generation in the generator which can be dissipated by the cooling device during subsequent operation.
- a very high current can be generated by the generator during cold starting, without implying any high losses and disturbing noise. Later, when the generator is heated and the demand for current decreases, the heat generated by the generator can be dissipated by the existing cooling device.
- Fig. 1 is a circuit diagram of an electrical system according to the present invention, which system comprises an alternating current generator, and
- Fig. 2 is a diagram showing the relationship between the voltage and temperature of the generator.
- Fig. 1 shows a circuit diagram of an electrical system according to the present invention.
- the system is preferably used in a motor vehicle and comprises an alternating current generator (below referred to as "generator"), the essential components of which are a magnetization winding 1, three stator windings 2, 3, 4 and a rectifier in the form of six diodes 5, 6, 7, 8, 9, 10.
- the system also comprises a capacitor 11, the purpose of which is to absorb voltage transients occuring during rectification.
- the magnetization winding 1 is arranged on a rotor and the stator windings are arranged on a stator. When the rotor is rotated, an alternating current is generated in the stator windings 2, 3, 4. This alternating current is rectified in the rectifier 5-10.
- the operation of the generator is known per se and is therefore not described in detail.
- the electrical system comprises a voltage regulator 12 to which a temperature sensor 13 is connected.
- the temperature sensor 13 emits a signal corresponding to a measure of the temperature T in connection with the generator. This signal is supplied to the voltage regulator 12.
- the output voltage of the generator is fed to an output terminal 14 which is connected to a battery 15, which is preferably in the form of the normal storage battery of the motor vehicle.
- the output terminal 14 of the generator is also connected to a plurality of electrical loads in the vehicle, which loads are illustrated symbolically by means of one single variable load 16. Furthermore, the battery 15 and the load 16 are connected to an earth point 17.
- An ignition lock 18 is connected between the voltage regulator 12 and the battery 15. During starting of the vehicle, the voltage regulator 12 can be activated by turning the ignition lock 18.
- An indicator 19 is arranged between the ignition lock 18 and the voltage regulator 12. The indicator 19, which preferably is constituted by a lamp or a light emitting diode, indicates that the ignition lock 18 has been switched on.
- the device according to the invention comprises a connector 20 between the voltage regulator 12 and one of the stator windings (in this case the stator winding 4).
- the voltage regulator 12 may detect one of the phases of the generated alternating voltage. In this manner, the regulator can be provided with a measure of the rotation speed of the rotor.
- the purpose of the voltage regulator 12 is to control the output voltage of the generator 1 so as to keep it essentially constant, regardless of the load and current of the generator.
- the voltage regulator 12 is adapted to supply a current to the magnetization winding 1. This current controls the degree of magnetization of the rotor of the generator. In this manner, the output voltage of the generator can be varied as a function of the current through the magnetization winding 1.
- the magnitude of said current can be controlled depending on the output voltage of the generator, i.e. the voltage at the output terminal 14, and depending on the temperature T.
- the voltage regulator 12 may comprise a field effect transistor (not shown), the conduction time of which may be controlled. In this manner, the magnitude of the current through the magnetization winding 1 can be controlled.
- the field effect transistor is preferably controlled by means of pulse width modulation, wherein a reduction of the duty cycle of the modulation gives rise to a reduction of the current through the magnetization winding 1.
- the temperature- and voltage-dependent control in the regulator 12 is shown schematically in the diagram in Fig. 2, which shows the relationship between the temperature T of the regulator 12 and the voltage U on the output terminal 14 of the generator.
- the relationship according to the diagram defines a voltage interval within which the output voltage U of the generator may vary, assuming a certain given temperature T. This variation is controlled by means of the control of the regulator 12.
- the voltage control is carried out as follows. First, the regulator 12 detects the output voltage of the generator, i.e. the voltage which is present on the output 14. This is carried out via a connector which is connected from the output 14 to the regulator 12 (see Fig. 1). Alternatively, the connector 20 from one of the stator windings 4 can be used for this purpose.
- the actual voltage value is compared with a predetermined set value in the regulator 12.
- the set value depends on the actual temperature T, in accordance with the diagram of Fig. 2, and is determined as a voltage value which is essentially "in the middle of" the voltage interval which corresponds to a certain temperature.
- the difference between the actual value and the set value generates a signal in the voltage regulator 12 which controls the current through the magnetization winding 1 of the rotor.
- the regulator 12 increases the current through the magnetization winding 1. This is carried out by means of the regulator 12 by an increase of the conduction time of a field effect transistor which is connected in series with the magnetization winding 1. This results in an increase of the output voltage of the generator on the output terminal 14.
- the battery 15 is supplied with an optimal voltage for recharging, though not such a high voltage that there is a risk for gassing in the battery 15.
- the system comprises a cooling device in the form of a fan which is arranged on the rotor so that the fan rotates when the rotor rotates.
- a cooling device in the form of a fan which is arranged on the rotor so that the fan rotates when the rotor rotates.
- the entire generator device including the regulator 12, can be cooled when the generator is operated.
- Fans for generators are known per se and are therefore not described in detail.
- the fan can however be made with relatively small dimensions, i.e. it can be designed so as to provide a relatively low cooling effect, for reasons which will be explained below.
- the generator When the ignition lock 18 is turned and the combustion engine (not shown) is started, the generator will be activated. This causes an alternating current to be generated in the stator windings 2, 3, 4, which current is rectified in the rectifier 5-10. The rectified output voltage is supplied to the battery 15 and the load 16. Furthermore, the generator 12 senses this output voltage via the connector between the regulator 12 and the terminal 14. Also, a value of the temperature T of the generator is supplied to the regulator 12 by means of the temperature sensor 13. In this regard, the regulator 12 controls the magnitude of the current to the magnetization winding 1 so that the voltage of the generator corresponds to the relationship shown in Fig. 2.
- the generator After a while, the generator will generate an energy loss, which results in that it will be heated. This results in turn in that cooling becomes necessary. Due to the fact that the invention comprises a fan of relatively small dimensions, i.e. having a relatively low cooling effect, only a ⁇ mall fraction of the heat will be dissipated in this initial phase. In this manner, a high coefficient of efficiency can be maintained during this phase. Furthermore, only very little noise is generated by the fan, since the fan is relatively small.
- a maximum load of the generator exists since a plurality of the electric consumers of the vehicle (for example electrical heating devices for the windows and the seats) are switched on. During this phase, the generator may develop all its output power.
- the fan forming part of the invention has relatively small dimensions, i.e. it has a relatively low cooling effect. This results in that the temperature T of the generator rises relatively quickly during a cold start, i.e. the temperature T rises quicker than if a conventional fan had been used.
- the temperature T of the generator will increase until it approaches a maximum allowed temperature limit T g , i.e. a temperature at which the components forming part of the generator may be damaged.
- T g a temperature at which the components forming part of the generator may be damaged.
- some of the electrical consumers in the vehicle will gradually be switched off, since some electrical consumers (for example electrical window heating devices) only have to be switched on immediately after start of the vehicle.
- the vehicle's demand for electric power decreases (i.e. the output power of the generator decreases).
- the power loss of the generator, and thus also its demand for cooling decreases.
- the power demand of the generator will thus have decreased to a value which corresponds to continuous operation of the vehicle.
- This "continuous value” is of a magnitude which is approximately 35% of the maximum power of the generator.
- the fan forming part of the invention is dimensioned so as to provide cooling power which is required for the demand for cooling which exists in this phase. Consequently, during normal operation the generator will never reach its temperature limit T g . Instead, the temperature will be stabilized at a value which is slightly lower than the temperature limit T g .
- the fan In conventional generators, the fan is dimensioned in accordance with the nominal load of the generator, so that it dissipates the power loss of the generator.
- the invention is based on the fact that the fan does not have to dissipate such a high power loss at maximum nominal power of the generator. The fan only dissipates the power loss which exists when the electrical consumers, which in principle are only used during a cold start, have been switched off.
- the temperature T of the generator increases until it reaches the maximum allowed value T g , i.e. a limit value which corresponds to a maximum allowed temperature which the generator may have without risk that the included components may be damaged.
- the regulator 12 will detect if the temperature limit T g is reached. In that case, the regulator 12 decreases the current to the magnetization winding 1 to a level which corresponds to the amount of heat which the fan manages to dissipate (i.e. the current is decreased to a level which corresponds to a power level of the generator at which the temperature of the generator is lower than said temperature limit T g ) .
- the regulation still follows the relationship according to Fig.
- the current to the magnetization winding 1 will be controlled to a level which corresponds to an output current from the generator at which a relatively low amount of heat is generated, more precisely an amount of heat which is not harmful to the components in the generator. This amount of heat may vary for different types of generators.
- the invention provides a generator operation with a higher coefficient of efficiency and with a lower level of disturbing noise from the generator.
- a very high current is required during cold starts.
- the required current for the switched-on current consumers can be approximately 200 A during starting in cold climate.
- the relatively small fan will be dimensioned so as to dissipate a power loss from the generator at a condition of balance which is reached at a time when the current demand in the vehicle has decreased, i.e. when for example the interior has been heated and frost on the windows has been removed. In this manner, an effective use of the generator is possible when a particularly high current demand exists.
- the invention is particularly intended for use in connection with motor vehicles, but can also be used together with generators in other applications.
- the invention uses a temperature sensor 13 which may be a separate sensor device which is connected to the regulator 12 or which alternatively can be one or several diodes which form part of the regulator 12, the temperature sensitivity of which is used as a temperature-detecting means.
- a separate temperature sensor it can be arranged on a particular component which is arranged in or in connection with the generator and which is particularly temperature-sensitive.
- cooling can be used in connection with the invention. Besides fans, water and air cooling can be used. No cooling device is needed in those cases where the current to the magnetization winding 1 is controlled down to a value corresponding to a very low generation of heat of the generator.
- the current to the magnetization winding 1 can be controlled as a function of the speed of the generator. This can be accomplished by arranging an engine speed sensor in connection with the generator or by using a measure of the speed of the generator via the connector 20. This regulation is based both on the fact that a predetermined relationship between the speed and temperature of the generator exists, and the fact that a cold generator generates a higher current than a hot generator, since the resistance in the stator windings changes with temperature.
- the generator does not have to be provided with any temperature sensor. This applies in those cases where the fan is sufficiently well-dimensioned so as to dissipate the loss of power with a sufficient margin to the temperature limit T g .
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
EP96927227A EP0872013A1 (en) | 1995-08-08 | 1996-08-08 | Device comprising a generator and method for control of such a device |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
SE9502773A SE516243C2 (en) | 1995-08-08 | 1995-08-08 | Apparatus comprising a generator and a cooling device as well as a method for cooling a generator |
SE9502773-6 | 1995-08-08 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO1997006594A1 true WO1997006594A1 (en) | 1997-02-20 |
Family
ID=20399130
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/SE1996/000995 WO1997006594A1 (en) | 1995-08-08 | 1996-08-08 | Device comprising a generator and method for control of such a device |
Country Status (3)
Country | Link |
---|---|
EP (1) | EP0872013A1 (en) |
SE (1) | SE516243C2 (en) |
WO (1) | WO1997006594A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102009047172A1 (en) * | 2009-11-26 | 2011-06-01 | Robert Bosch Gmbh | Method for temperature-dependent controlling power output of motor vehicle generator, involves detecting temperature of generator, and supplying temperature to control unit to change output power of generator |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3012364C2 (en) * | 1980-03-29 | 1985-06-05 | Triumph-Adler Aktiengesellschaft für Büro- und Informationstechnik, 8500 Nürnberg | Method for feeding an electric motor |
US4686446A (en) * | 1985-03-14 | 1987-08-11 | Mitsubishi Denki Kabushiki Kaisha | Power generation control apparatus for alternating current generator |
US4890050A (en) * | 1987-10-06 | 1989-12-26 | Vanguard Products Corporation | Automotive alternator |
US5198744A (en) * | 1990-06-21 | 1993-03-30 | Robert Bosch Gmbh | Apparatus and method for controlling the output power of a generator to maintain generator temperature below an allowed limiting value |
-
1995
- 1995-08-08 SE SE9502773A patent/SE516243C2/en not_active IP Right Cessation
-
1996
- 1996-08-08 WO PCT/SE1996/000995 patent/WO1997006594A1/en not_active Application Discontinuation
- 1996-08-08 EP EP96927227A patent/EP0872013A1/en not_active Ceased
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE3012364C2 (en) * | 1980-03-29 | 1985-06-05 | Triumph-Adler Aktiengesellschaft für Büro- und Informationstechnik, 8500 Nürnberg | Method for feeding an electric motor |
US4686446A (en) * | 1985-03-14 | 1987-08-11 | Mitsubishi Denki Kabushiki Kaisha | Power generation control apparatus for alternating current generator |
US4890050A (en) * | 1987-10-06 | 1989-12-26 | Vanguard Products Corporation | Automotive alternator |
US5198744A (en) * | 1990-06-21 | 1993-03-30 | Robert Bosch Gmbh | Apparatus and method for controlling the output power of a generator to maintain generator temperature below an allowed limiting value |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE102009047172A1 (en) * | 2009-11-26 | 2011-06-01 | Robert Bosch Gmbh | Method for temperature-dependent controlling power output of motor vehicle generator, involves detecting temperature of generator, and supplying temperature to control unit to change output power of generator |
Also Published As
Publication number | Publication date |
---|---|
SE516243C2 (en) | 2001-12-10 |
SE9502773L (en) | 1997-02-09 |
SE9502773D0 (en) | 1995-08-08 |
EP0872013A1 (en) | 1998-10-21 |
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