DE102008002118A1 - Apparatus and method for generator control and generator with corresponding device - Google Patents

Abstract

The invention relates to a device for controlling a generator, in particular a starter-generator, of a motor vehicle in which the respective operating phase of the generator can be controlled by means of a control device. It is envisaged that limiting the power of the generator, which experiences excitation phases and de-excitation phases by means of an external specification, takes place during the excitation phase of the generator. Furthermore, the invention relates to a generator with a corresponding device and a corresponding method.

Description

The On the one hand, the invention relates to a device for controlling a Generator, in particular starter generator, a motor vehicle with the features mentioned in the preamble of claim 1 and a generator with a corresponding device with the in the preamble of Claim 8 mentioned features. On the other hand, the invention relates a corresponding method for controlling a generator, in particular Starter generator, a motor vehicle with the in the preamble of Claim 9 mentioned features.

State of the art

An apparatus and a method for controlling a generator of the type mentioned are, for example, from US 6,166,523 A known. In this case, depending on the state of charge of the vehicle battery and the operating state of the vehicle, the generator is turned on or off. By charging and discharging the battery of the vehicle based on its state of charge, a load caused by the generator can be reduced, thereby saving energy and optimizing the fuel efficiency of the vehicle. Based on set limit values of the state of charge of the vehicle battery, the generator can be switched on or off depending on whether the state of charge of the vehicle battery is within the limits. Consequently, the generator is turned on only when needed, which avoids unnecessary charging and the battery of the vehicle can be operated as efficiently as possible.

Of the Efficiency of the generator is not over all Operating states constant. He is rather dependent from its constructive interpretation and changes, for example with speed and utilization as well as with the temperature. The optimal Efficiency of the generator is at a capacity of about 70% before. When operating near full load or at lower Utilization, the efficiency is lower. One in this regard used to control unit serves to the respective Adjusting the operating state of the generator with the entire vehicle. In this case, a use case can typically be taken into account which is called recuperation mode. In recuperation mode is in overrun mode of the vehicle, that is in one by the downgrade force and / or by the inertia force Conditional operation, an occurring braking energy by increasing the generator voltage converted into electrical energy and, for example cached in the vehicle battery. When accelerating the vehicle then becomes the generator output power of the generator reduced to its de-energizing, to the generator drag torque to reduce a powertrain of the vehicle and thus more Torque available for acceleration to deliver. During this time, the electrical system becomes the vehicle from the energy storage, for example a battery, provided. After that, for example, after graduation of the acceleration process, the generator takes over again the supply of the electrical system and the reloading of the Battery. In a typical vehicle cycle, the alternator changes after his state of deprivation first for a finite time in its full load condition, which makes the generator less common is operated in the range of optimum efficiency. In extreme cases The generator even alternates between the states de-energizing and full load, so that operation of the generator is rare or never takes place in the region of optimum efficiency.

Disclosure of the invention

The Inventive device for controlling a Generators with the features mentioned in claim 1 offers the other hand the advantage that the time duration while the generator is operated in the area of highest efficiency, increases, which ultimately both fuel consumption the internal combustion engine of the vehicle as well as its emission values can be improved. This is a scheduled Limiting the power of the generator, by an external specification Excitement phases and phases of excitement experience while the excitement phase. As long as there is the charge balance of the battery and others Allow boundary conditions, thus the performance of the generator limited to the operating state de-energizing. The limitation occurs such that a higher efficiency of the generator achieved becomes. The same applies analogously to the generator with a corresponding device having the features of the claim 8 and for the method of controlling the generator with the features of claim 9.

advantageous Further developments result from the characteristics of the dependent Claims.

With Advantage is the limitation of the power of the generator immediately after the de-energizing phase. The limitation is done here, for example to a value that has the highest efficiency.

advantageously, the limitation of the power of the generator is dependent of boundary conditions, in particular charge balance of a vehicle battery, so that the power limitation of the generator takes place only if certain conditions are met. This is in an electric or hybrid vehicle, in particular the vehicle battery in the field of vision.

A Further advantageous development of the invention provides that limiting the power of the generator to a value provided is for which a generator voltage in a for an electrical system of the motor vehicle is appropriate area. The performance of the generator can not be chosen arbitrarily. Much more Care must be taken in the choice of performance that the Generator voltage changed only in a limited range be allowed to operate properly of the electrical system. The size of the Range and a nominal voltage are due to properties of the electrical system specified. A change in performance is thus such that, on the one hand, the generator voltage in the given On the other hand, the efficiency of the generator is maximized is.

In An advantageous embodiment of the invention is provided that limiting the power of the generator to one the highest Efficiency of the generator corresponding value takes place, thereby the generator is significantly more common in the range of its optimal Operating phase is used. This delays Although the recharging of the battery, which, however, on the charge balance does not affect the frequency of these operating conditions is controlled accordingly.

According to one preferred embodiment of the invention, it is provided that the controlled limitation of the output power of the generator based a specification of a maximum permissible excitation current takes place, allowing the generator in different states respectively brought with a comparatively higher efficiency can be.

According to one further preferred embodiment of the invention, it is provided that the controlled limitation of the power of the generator based a maximum allowable duty cycle an excitation circuit final stage takes place. This can, for example by means of a digital controller interface of a separate control unit the generator is supplied with an appropriate signal.

The Advantages of Dependent Device Claims 2 to 7 apply analogously to the features the dependent method claims 9 to 14.

Brief description of the drawings

The Invention and advantageous embodiments according to the Features of the further claims are described below the embodiments shown in the drawings explained in more detail, without that being a restriction the invention takes place; rather, this includes all modifications, changes and equivalents that are possible under the claims are. Show it:

1 an efficiency map of a generator with exemplified operating states thereof;

2 another efficiency map of the generator taking into account a load point shift; and

3 a map of an internal combustion engine, in particular internal combustion engine, for representing the specific fuel consumption, including the specific work and the engine or engine speed.

Embodiment (s) of the invention

In 1 is a diagram 10 with an efficiency map 11 a generator, not shown, in which the generator current I _G is plotted against the generator speed n _G. Here, for a given first speed, characterized by the line 12 , depending on the output power of the generator, for example, three different operating states 13 . 14 and 15 can be adjusted, but the efficiency of the generator is not constant over all operating conditions. The efficiency is rather dependent on the structural design of the generator and changes, for example, with the generator speed, the generator utilization and the generator temperature. The optimum efficiency of the generator is at a capacity utilization of about 70%. A used in this context, the control unit is used to tune the respective operating state of the generator with the entire vehicle.

in this connection a use case can typically be considered, which is called recuperation mode. In recuperation mode in the overrun mode of the vehicle an occurring braking energy by an increase of the generator voltage into electrical energy converted and, for example, in an energy storage, for example the vehicle battery, cached. When accelerating the Vehicle then becomes the generator output power of the generator reduced to its de-energizing, to a generator drag torque to reduce the powertrain of the vehicle. While This time is an electrical system of the vehicle from the Energy storage, for example, the vehicle battery supplied. in the Follow it, so usually when completed Acceleration process, the generator takes over again the supply of the electrical system and the reloading of the Battery.

In Rekuperationsmodus, so when recovering electrical energy, for example during a braking operation of the vehicle, the operating state of the generator when charging the battery is the operating state 13 according to 1 taking. By a controlled limitation of the output power of the generator in the other operating conditions 14 and 15 according to 1 be brought with higher efficiencies. This corresponds to a sub-area 15.1 of the operating state 15 a maximum of the efficiency of the generator. By means of an arrow 16 is a tendency of the efficiency of the generator within the efficiency map 11 to 1 shown, which is decreasing with increasing generator current I _G and increasing generator speed n _G. The controlled limitation can be effected, for example, by specifying a maximum permissible exciter current or a maximum permissible switch-on ratio of an excitation circuit final stage, wherein the generator can be supplied with a corresponding signal by means of a digital controller interface of a separate control unit.

According to 2 is another efficiency map 17 a generator shown in which the generator current I _G is plotted against the generator speed n _G. The further efficiency map 17 stands here as a representative of a principle in which a load point shift is mapped. The efficiency map 17 is with a series of field segments 18 to 22 provided, wherein the most obvious to the zero point of the coordinate system shown field segment 18 corresponds to an efficiency of> 70%. The other field segments 19 . 20 . 21 and 22 correspond in the order given an efficiency of>65%,>60%,> 55% or> 50%. A first field area 23 , which is marked with a left-facing surface hatching, in this context forms a relevant first area for the load point shift. One below the first field area 23 adjacent second field area 24 Consequently, it forms the area in which the load point is to be shifted in order to improve the efficiency of the generator. According to the first field area 23 is below the second field area 24 a third field area 25 , which is marked with a right-facing surface hatching. The third field area 25 forms in this context a relevant further area for the load point shift. Exemplary is within the third field area 25 a load point 26 entered in the direction of the arrow 34 in the second field area 24 to the new load point 26 ' to increase the efficiency of the generator is shifted, for example, the difference of the generator current +20 A and the difference of the generator speed can be + 10%. In the example shown, the generator current is increased by 20 A, which increases the efficiency by 10%.

In 3 a map 27 an internal combustion engine, in particular internal combustion engine, for representing the specific fuel consumption (g / kWh) including the specific work and the engine or engine speed shown. The specific work w _e is shown here above the engine speed n _M. The specific work is the work that an engine performs, based on the displacement, for example in the dimension kJ / dm ³ . It is a comparison of different engines regardless of the engine displacement. There is a distinction between indexed and effective specific work. While the indicated specific work results from the pressure history in the combustion chamber, the effective specific work refers to 3 on the work done on the shaft.

According to the 2 are also in 3 defined three field areas. A first field area 28 , which is marked with a left-facing surface hatching, in this context forms a relevant first area for the load point shift. One below the first field area 28 adjacent second field area 29 Consequently, it forms the area in which the load point is to be shifted in order to improve the efficiency of the generator. According to the first field area 28 is below the second field area 29 a third field area 30 , which is marked with a right-facing surface hatching. Within the third field area 30 is an example of a load point 31 shown corresponding to a low specific work and according to the arrow direction 35 in the second field area 29 to shift is to achieve an increase in efficiency, which is an (exemplary) load point 31 ' results. Furthermore, within the second field area 29 a load point 32 shown, which is achievable at high specific work. In this respect, the map clarifies 27 the tendency direction 33 for the load point shift in a generator from the point of view of the internal combustion engine, in particular internal combustion engine.

A possible functional implementation of the load point shift essentially comprises on the one hand a basic function which has validity for the operating states acceleration, constant speed or idling of the internal combustion engine. On the other hand, by said functional implementation, a special case, in particular a push operation, are taken into account. In the basic function, the generator or the internal combustion engine are in a functional area according to 2 or in a functional area according to 3 , For this purpose, the following cases can be mapped according to a state machine, in particular according to the following allocation table: operating condition operating condition control generator internal combustion engine Generator voltage U _{G should} field area 23 field area 28 U _{G soll} = U _{G normal} - delta U _h field area 23 field area 28 U _{G soll} = U _{G normal} - delta U _k field area 23 field area 28 U _{G soll} = U _{G normal} field area 24 field area 29 U _{G soll} = U _{G normal} - delta U _k field area 24 field area 29 U _{G soll} = U _{G normal} field area 24 field area 29 U _{G soll} = U _{G normal} + delta U _k field area 25 field area 30 U _{G soll} = U _{G normal} field area 25 field area 30 U _{G G} U _soll = _normal + delta U _k field area 25 field area 30 U _{G soll} = U _{G normal} + delta U _h

For the special case of overrun operation, a general increase in the generator voltage U _G to be achieved is to be carried out, according to which U _{G soll} = U _{G normal} + delta U _h applies.

U_{G soll}

= Vorgabewert/Sollwert der Betriebsspannung,

U_{G normal}

= Normale Betriebsspannung (temperaturkompensiert),

delta U_h

= Hohe Spannungsänderung (im zulässigen Bereich) und

delta U_k

= Kleinere Spannungsänderung als delta U_h.

In the cases mentioned above, the following assignments are used:

U _{G should}

= Default value / nominal value of the operating voltage,

U _{G normal}

= Normal operating voltage (temperature compensated),

delta U _h

= High voltage change (within the permissible range) and

delta U _k

= Smaller voltage change than delta U _h .

A load point shift may only take place in such a way that the output voltage of the generator is within the voltage ranges specified in the assignment table. In this case, U _{G normally} indicates the voltage which is usually used for the electrical system of the motor vehicle, while delta Uh specifies a maximum permissible voltage deviation and delta U _k a smaller deviation. In normal operation of the vehicle (in the field areas 24 and 29 ) the actual generator voltage U _{G should be} in the range of U _{G normal} - delta U _k to U _{G normal} + delta U _k . In unfavorable driving conditions (for example in one of the field areas 23 . 25 . 28 or 30 ), the deviation may be greater, so that the generator voltage U _{G should} lie in the range of U _{G normal} - delta U _h to U _{G normal} + delta U _h . This limitation of the permissible generator voltage range thus limits the possible extent of a load point shift. The variables U _{G normal} , delta U _h , and delta U _k are determined by the requirements of the electrical system. The voltage U _{G should} be adjusted in the course of the load point shift such that the best possible efficiency of the generator is present.

A regulation of the generator voltage U _{G should} be done, for example, via an adjustment of the external excitation.

In summary The present technical solution relates to a device and a method for controlling a generator, in particular a starter generator, a motor vehicle, in which by means of a control device the respective operating phase of the generator is controlled. in this connection is the power of the generator, by an external default Excitement phases and phases of excitement experience while the excitation phase of the generator targeted and on schedule limited. Furthermore, the present invention relates to a generator with a corresponding device. The power limitation of the Generator is used to increase its efficiency, especially in the course of a load point shift.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - US 6166523 A [0002]

Claims (15)

Device for controlling a generator, in particular a starter-generator, of a motor vehicle, in which the respective operating phase of the generator can be controlled by means of a control device, characterized in that a limitation of the power of the generator, which experiences excitation phases and de-excitation phases by an external specification, during the Excitement phase is provided. Device according to claim 1, characterized in that that limiting the power of the generator immediately after the de-energizing phase is provided. Device according to one of the preceding claims, characterized in that limiting the power of the generator depending on boundary conditions, in particular one Charge balance of a vehicle battery, is provided. Device according to one of the preceding claims, characterized in that limiting the power of the generator is provided to a value for which a generator voltage in a suitable for an electrical system of the motor vehicle Area is located. Device according to one of the preceding claims, characterized in that limiting the power of the generator to a value corresponding to the highest efficiency of the generator is provided. Device according to one of the preceding claims, characterized in that the controlled limitation of the power of the generator based on a default of a maximum allowable Excitation current is provided. Device according to one of the preceding claims, characterized in that the controlled limitation of the power of the generator based on a maximum allowable duty cycle an exciter circuit output stage is provided. Generator, in particular starter generator, one Motor vehicle, characterized by a device according to a of the preceding claims. Method for controlling a generator, in particular Starter generator, a motor vehicle, in which by means of a control unit the respective operating phase of the generator is controlled, thereby characterized in that the power of the generator, by a external specification excitation phases and phases of deprivation, is limited during the excitation phase. Method according to claim 9, characterized that the power of the generator immediately after the de-energizing phase is limited. Method according to one of the preceding claims, characterized in that the power of the generator in dependence of boundary conditions, in particular a charge balance of a vehicle battery, is limited. Method according to one of the preceding claims, characterized in that the power of the generator to a Value is limited, for a generator voltage in one for a vehicle electrical system suitable area lies. Method according to one of the preceding claims, characterized in that the power of the generator to a corresponding to the highest efficiency of the generator Value is limited. Method according to one of the preceding claims, characterized in that the power of the generator based controlled a specification of a maximum permissible excitation current is limited. Method according to one of the preceding claims, characterized in that the power of the generator based a maximum allowable duty cycle an exciter circuit output stage controlled limited.