EP2583367A2

EP2583367A2 - Method and device for compensating a drop in the output voltage of a motor vehicle generator

Info

Publication number: EP2583367A2
Application number: EP11724413.7A
Authority: EP
Inventors: Michael Herz; Andre Micko
Original assignee: Robert Bosch GmbH
Current assignee: SEG Automotive Germany GmbH
Priority date: 2010-06-11
Filing date: 2011-06-06
Publication date: 2013-04-24
Also published as: CN102918744B; JP5832529B2; CN102918744A; WO2011154346A2; JP2013528347A; DE102010029967A1; US8963509B2; US20130141055A1; WO2011154346A3

Abstract

The invention relates to a method for compensating a drop in the output voltage of a motor vehicle generator due to a load connection or a rotational speed change by means of a generator controller, which provides a control signal, which has a duty factor and which increases the exciting current of the motor vehicle generator. After the voltage drop occurs, the duty factor of the control signal is increased by a difference amount in a first step, and the adjustment speed is limited in a subsequent second step. After the voltage drop occurs, parameters that describe the instantaneous operating point of the motor vehicle generator are detected, and the difference amount is set in accordance with the operating point in the first step.

Description

Description title

Method and device for compensating for a break in the output voltage of a motor vehicle generator

The invention relates to a method and a device for compensating for a break in the output voltage of a motor vehicle generator.

State of the art

The vehicle electrical system of a motor vehicle is powered by a generator whose output voltage is controlled by a generator controller to a predetermined value, for example to 14V. Load connections or speed changes in the motor vehicle can lead to a collapse of the vehicle electrical system voltage. The generator controller controls this voltage dip, which increases the torque request to the driveline or to the engine. The connection of the load requires a higher torque to drive the generator. The regulation takes place by an increase of the exciting current in the rotor of the generator device. This increase is brought about by an increase in the duty cycle of a PWM signal set by the generator controller. By changing the magnetic field resulting from the exciting current, the voltage induced in the stator is increased.

In the case of a rapid control of a voltage dip, there is also a correspondingly rapid increase in the moment-determining excitation current. In particular, at low speeds, the engine often can not apply the moment sufficiently quickly. In this case, the engine is braked by the generator. This can cause a stalling of the engine. In order to prevent such stalling of the engine, it is already known to limit the Ausregelungsgeschwindigkeit a generator controller in the lower speed range. This so-called load response function limits the rate of change of the duty cycle, if this must be increased due to a voltage dip. This is the same extent the

Changes the rate of change of the moment, so that the engine has more time to respond to the increased torque requirements. The disadvantage of this approach, however, is that this causes a corresponding delay in the regulation of the voltage dip. The voltage dip lasts longer.

If only small loads are switched on and thus the duty cycle has to be increased only slightly, then the moment is only slightly increased, which is generally not critical for the engine. In order not to have to accept a slow regulation of a voltage dip caused by the load response function even with such small load changes, it is already known that the duty cycle is first of all limited by a predetermined value, also as "blind zone" or "blind zone". is called to increase, so that a rapid response to the voltage dip takes place, and only then to increase further with the limit limited by the load response function slew rate.

The "blind zone" or "blind zone" is defined as the duty cycle delta, within which a fast compensation can take place. With current controllers, the "blind zone" is set to a fixed value or can be switched between two values. The resulting possible loads, which can be quickly corrected, as well as the resulting possible torque changes, are not constant, but depending on the particular operating point of the generator. Reasons for this dependence on the operating point are, for example, the temperature-variable properties of the exciter winding (resistance and inductance) and the disproportionate nature of the exciting current to the generator current, which is caused by the saturation behavior of the rotor core. "

From DE 199 05 984 AI a control device for a motor vehicle alternator is known, which is driven by an internal combustion engine and after a rectification of the output voltage generated by it a Batte- invites you. This control device includes a voltage regulator that controls the charging voltage of the battery to a constant value, and a device that gradually increases the generator current of the alternator after turning on an electric load. The increase amount of a control current of a circuit breaker for controlling the excitation current of the alternator to a

Time immediately after the switching on of the electric load, but before the activation of the means for controlling a gradual excitation, is adjusted depending on the power generation conditions of the alternator. Specifically, the increase amount of the control current of the power switch for controlling the exciting current of the alternator is set in accordance with the generator current of the alternator such that when the generator current is large, the amount of increase is increased and lowered with small generator current. Alternatively, the increase amount of the control current of the power switch for controlling the exciting current is set to be proportional to the energization current value before the turning-on of the electric load. Thus, when using the same control device for generators having different generator power capacities, the output current of the respective alternator providing a one-time and immediate response to a load being turned on before the activation of the gradual energization control gradually increases the generator current. represents, is kept substantially constant.

DISCLOSURE OF THE INVENTION A method having the features specified in claim 1 and a device having the features specified in claim 5 have the advantage that the choice of the difference by which the duty cycle of the control signal is increased, made depending on the respective operating point becomes. This adaptation of the blind zone to the operating point present in each case leads advantageously to a predictable and clearly defined behavior of the generator, which can be optimized for the respective operating points of the engine. As a result, for example, more complex functions in the control unit for responding to torque changes on the drive train due to the generator can be minimized.

Further advantages of the invention are that in the different operating points not always constant conditions, for example constant mo- ment changes or constant quickly adjustable voltage dips, but also different conditions may exist, for example, different operating points may be assigned to different torque changes.

Hereinafter, an embodiment of the invention will be explained in more detail with reference to the drawing. It shows

FIG. 1 shows a circuit diagram for explaining a device for compensating a break in the output voltage of a motor vehicle generator based on a load connection;

Figure 2 diagrams for explaining a known method and

Figure 3 diagrams for explaining a method according to the invention.

FIG. 1 shows a circuit diagram for explaining a device for compensating a break in the output voltage of a motor vehicle generator based on a load connection. The device shown has a generator device 11, the electrical system 12 of the motor vehicle and detector means 13. The generator device 11 comprises a generator controller 1 and a generator unit 10, which provides at its output a DC supply voltage for the electrical system 12 of a motor vehicle.

The generator unit 10 has a generator 2 and a rectifier arrangement 9. The generator 2 includes a field winding 5 and not shown phase windings, which are interconnected, for example in the form of a star connection or a delta connection. The generator 2 provides at its phase voltage terminals U, V and W AC voltages available to the downstream rectifier assembly 9 are supplied. As an alternative to the exemplary embodiment shown, a different number of phases or phase voltage connections may also be present.

The rectifier assembly 9 includes three branches, each having a series connection of two diodes or other suitable components and associated with another of the phase voltage terminals of the generator. The phase voltage terminal U of the generator 2 is connected to the connection point between the diodes Dl and D4 of the first rectifier branch. The phase voltage terminal V of the generator 2 is connected to a connection point between the diodes D2 and D5 of the second rectifier branch. The phase voltage terminal W of the generator 2 is connected to a connection point between the diodes D3 and D6 of the third rectifier branch.

The cathodes of the diodes D4, D5 and D6 are connected together. There, the DC output voltage of the generator unit 10 is provided and to the

On-board network 12 passed. The anodes of the diodes Dl, D2 and D3 are also connected to each other and are grounded.

The phase voltage terminal W of the generator 2 is further connected via a terminal X of the generator controller 1 with the controller control 7 of the generator controller 1 and via a resistor R3 and a ground connection 3 of the generator controller to ground 4 in combination.

The generator controller 1 has an operating voltage connection B + and further connections DF, D and X. Furthermore, the generator controller contains a

Controller controller 7, which is provided with an evaluation logic. The regulator controller 7 is provided to provide a switching transistor 6 with a PWM drive signal s. The regulator controller 7 is furthermore connected to the operating voltage connection B + and via the ground connection 3 to ground 4. Further, the regulator controller 7 communicates with the terminal X of the generator regulator 1 to receive a phase voltage signal derived from the phase voltage terminal W of the generator 2.

In addition, the device shown in FIG. 1 has an exciter circuit. This runs from the operating voltage connection B + of the generator controller 1 via the switching transistor 6 of the generator regulator, the DF connection of the generator regulator, the excitation winding 5, the D connection of the generator regulator and the ground connection 3 to ground 4. Between the connections D and DF of the generator regulator 1 either a freewheeling diode 8 is switched or it is used an active freewheel with a switching transistor. The regulator controller 7, which is connected to the operating voltage terminal B + and via the terminal X to the phase voltage terminal W of the generator 2, controls the switch 6 with the control signal s such that an exciting current flows through the excitation winding 5, both from the Be - Tension voltage connection B + present DC voltage as well as temporarily dependent on the her via the terminal X fed phase voltage.

Occurs in such a device due to a connection of a load in the electrical system on a collapse of the output voltage of the motor vehicle generator, then this is detected by the controller controller 7. The controller control is designed such that it brings about a compensation of the voltage drop on occurrence of such a voltage dip. This occurs as follows: After the load connection has occurred, the controller controller 7 acquires the parameter values of the signals supplied to it by the detector means 13. These signals correspond to parameters which describe the instantaneous operating point of the motor vehicle generator 2, so that the controller controller can determine the instantaneous operating point of the motor vehicle generator from the parameter values supplied to it. These parameters, whose parameter values allow conclusions to be drawn about the instantaneous operating point of the motor vehicle generator, include a rotational speed and a temperature. This speed is the generator speed and / or the engine speed. The temperature is the generator temperature and / or the regulator temperature and / or the engine compartment temperature and / or the ambient temperature. Further parameters describing the instantaneous operating point of the motor vehicle are, for example, the load on the generator and / or the exciter current and / or the duty cycle and / or the battery voltage and / or the generator voltage. The information about the excitation current and the duty cycle are the controller control anyway. The information about further parameters whose parameter values allow conclusions to be drawn about the instantaneous operating point of the motor vehicle generator are supplied to the controller control by the detector means 13. If the controller controller has determined from the parameters mentioned the instantaneous operating point of the motor vehicle generator, then it selects an operating point-dependent amount associated with this operating point, by which the instantaneous duty cycle of the control signal s is increased in order to initiate an optimal for this operating point compensation of the voltage drop occurred, and leads in a first step the switching transistor 6, a control signal s with the increased duty cycle to. As a result, the excitation current flowing through the field winding 5 is also increased, which in turn leads to an increase in the output voltage of the generator device.

To select the operating point-dependent amount by which the instantaneous duty cycle of the control signal s is increased, the controller controller 7 addresses a memory 14 in which a map is stored, in which a plurality of operating points is assigned a difference amount.

Subsequently, the controller controller generates the control signal s in a second step such that the Ausregelgeschwindigkeit is limited and thus performs a load response function.

Consequently, in the present invention, after the occurrence of a voltage dip occurring due to a load connection, the instantaneous operating point of the motor vehicle generator is first determined and the duty cycle of the control signal s fed to the switching transistor T6 is increased by an operating point-dependent difference. Thereafter, in a second step, a limitation of the Ausregelgeschwindigkeit in the sense of a load response function.

FIG. 2 shows diagrams for explaining a known method. FIG. 2 a shows the duty cycle of the control signal s over time, in FIG. 2 b the load L of the generator over time. At a time t 1, a first load is switched on and at a time t 2 a second load is switched on. Both load connections cause a collapse of the output voltage provided by the generator device.

It can be seen from FIG. 2a that at the instant t1 the duty cycle of the control signal s is suddenly increased by an amount B in a first step and then slowly increases further in a second step in the sense of a load response function in order to correct the voltage dip. Thereafter, the duty cycle remains unchanged until time t2. At time t2, the duty cycle of the control signal s in turn jumps in a first step increases the amount B and then slowly further increased in a second step in the sense of a load response function to compensate for the further voltage dip. The amount by which the duty cycle of the control signal s is increased abruptly, ie the blind zone B, coincides with both load connections and is independent of the operating point at which the generator is currently located at the time the respective load connection occurs. The duration of the load response function, which continues until the respective voltage dip is corrected, is different in the embodiment shown.

From FIG. 2b it can be seen that the portion of the switched-on load, which is rapidly regulated by the connection of the load at the time t1 via the blind zone, that is to say the load. before the load response function starts, it has the value Δ1 and the quickly regulated part of the switched-on load has the value Δ2, where Δ1 is greater than Δ2. This is due to the fact that the generator is at a different operating point at time t 1 than at time t 2.

FIG. 3 shows diagrams for explaining a method according to the invention. In FIG. 3 a the duty ratio of the control signal s is plotted against time, in FIG. 3 b the load L of the generator over time. At a time t 1, a first load is switched on and at a time t 2 a second load is switched on. Both load connections cause a collapse of the output voltage provided by the generator device. From the figure 3a it can be seen that at the time tl, the duty cycle of

Control signal s in a first step is suddenly increased by an amount Bl and then slowly increases in a second step in the sense of a load response function to correct the voltage dip. Thereafter, the duty cycle remains unchanged until time t2. At time t2, the duty cycle of the control signal s in a first step is suddenly increased by the amount B2 and then slowly further increased in a second step in the sense of a load response function to compensate for the further voltage dip. The amount by which the duty cycle of the control signal s is increased abruptly, ie the blind zone, is different for the two load connections. When the load is switched on at time t 1, a blind zone B 1 is used; at the time of load connection, a blind zone B 2 is used at time t 2, wherein B 1 is greater than B 2 in the illustrated embodiment. The choice of blind ne has been made as a function of the operating point present at the time of the respective load connection, as has been explained above in connection with FIG. The duration of the load response function, which continues until the respective voltage dip is regulated, is different also in this embodiment.

It can be seen from FIG. 3b that the rapidly regulated portion of the switched-on load at time t 1 and the rapidly regulated portion of the switched-on load at time t 2 each have the value Δ, that is to say coincide.

Claims

claims

1. A method for compensating a based on a load switching or a speed change break the output voltage of a motor vehicle generator by means of a generator regulator, which provides a duty cycle exhibiting, the excitation current of the motor vehicle generator control signal, wherein after the occurrence of the voltage dip in a first step, the duty cycle of the control signal is increased by a difference and the Ausregelgeschwindigkeit is limited in a subsequent second step, characterized in that after the occurrence of the voltage dip the current operating point of the motor vehicle generator descriptive parameters are detected and in the first step, a working point-dependent adjustment of the difference is made.

2. The method according to claim 1, characterized in that the parameters describing the instantaneous operating point of the motor vehicle generator include a speed and a temperature.

3. The method according to claim 2, characterized in that to the current working time of the motor vehicle generator descriptive parameters include the generator speed and / or the engine speed.

4. The method according to claim 2, wherein the parameters describing the instantaneous operating point of the motor vehicle generator include the generator temperature and / or the regulator temperature and / or the engine compartment temperature and / or the ambient temperature.

5. The method according to any one of claims 2-4, characterized in that at the current operating point of the motor vehicle generator descriptive parameters, the load of the generator and / or the Erre gerstrom and / or the duty cycle and / or the battery voltage and / or the generator voltage include.

6. The method according to any one of the preceding claims, characterized in that the difference amount is taken from a stored map, in which a plurality of operating points each have a difference amount is assigned.

7. The method according to any one of the preceding claims, characterized in that different difference points are assigned to different operating points.

8. A device for compensating a break-in of the output voltage of a motor vehicle generator based on a load connection or a speed change, with a generator controller providing a duty cycle increasing the excitation current of the motor vehicle generator control signal, wherein the generator regulator in a first step after the occurrence of the voltage dip Duty cycle of the control signal increased by a differential amount and limits the Ausregelgeschwindigkeit in a subsequent second step, characterized in that it comprises detector means (13) which detect after the occurrence of the voltage dip the current operating point of the motor vehicle generator descriptive parameters, the detector means with the generator controller (1 ), the generator regulator is provided to determine the operating point of the motor vehicle generator by evaluating the detector signals provided by the detector means eln and in the first step to make an operating point-dependent adjustment of the difference.

9. Apparatus according to claim 8, characterized in that it comprises a memory (14) in which a map is stored, in which a plurality of operating points each have a difference amount is assigned.

10. Device according to one of claims 8 - 9, characterized in that in the map different operating points different differences are assigned.