Method for on-board power system diagnosis

Abstract

The invention relates to a method for diagnosing an onboard power system by means of a voltage regulator (240, 270), comprising: detecting (10) an output signal of a voltage regulator (240, 270) by means of a control device, the voltage regulator being designed to regulate a voltage for an onboard power system (220) of a vehicle provided by a generator (200) via a converter (250, 260); determining (20) an instantaneous power output (100) to the onboard power system (220) based on the detected output signal; and evaluating (30) the determined power output (100) for diagnosing the onboard power system (220) and at least one electrical load connected to the onboard power system.

Description

Technical Field

[0001] The invention relates to a method for carrying out onboard power supply diagnosis in a motor vehicle, in particular a two-wheeled motor vehicle, by means of a controller, as well as a computing unit for carrying out the method and a computer program for carrying out the method. Background Art

[0002] Motorized two-wheeled vehicles usually have a lighting generator or an AC or three-phase generator, which is mounted on the crankshaft or connected to the crankshaft and serves to charge the battery, which in turn supplies current to the vehicle's onboard power supply. Since the AC or three-phase current provided by the generator is not suitable for directly charging the battery, the current is converted into a DC current via a rectifier connected downstream. Instead of a rectifier, a converter with semiconductor switches can also be installed, which can be selected to work as a rectifier or inverter and allows the generator to be operated occasionally as a motor. In addition, it is necessary to regulate the generator power in order to maintain the rated value of the charging voltage of the battery. Usually, both functions are unified in a rectifier-regulator unit (also called RR unit, rectifier-regulator unit). Summary of the invention

[0003] According to the invention, a method for onboard power supply system diagnosis is proposed, as well as a computer unit for carrying out the method and a computer program for carrying out the method, having the features of the independent claims. Advantageous embodiments are the subject matter of the independent claims and of the description below.

[0004] In particular, a method for onboard power supply system diagnosis by means of a voltage regulator is proposed, wherein the voltage regulator is designed to regulate the voltage provided by a generator via a converter for an onboard power supply system of a vehicle by outputting an output signal, wherein the method comprises the following steps: detecting the output signal of the voltage regulator by means of a control device, determining the instantaneous power output to the onboard power supply system based on the detected output signal, and evaluating the determined power output for diagnosing the onboard power supply system and at least one electrical load connected to the onboard power supply system. In this way, the onboard power supply system can be diagnosed without significantly interfering with already existing components, by merely forwarding the output signal of the voltage regulator to the control device. The control device can be an engine control unit or an ABS control unit.

[0005] The evaluation of the power output can be performed, for example, based on information associated with the instantaneous operating state of at least one electrical load. The information can be, for example, a switch-on signal or switch-off signal of a load, which is identified, for example, by manipulating the load or detecting other signals (operation of a switch, etc.). The information can also be the expected or current power demand of the load, which is suitably stored, for example, in a storage unit.

[0006] According to one embodiment, the detected output signal and / or the result value of the evaluation and / or the instantaneous power output can be output via an interface, for example to suitable diagnostic software or to other control devices, or to an external diagnostic device.

[0007] Optionally, the evaluation of the power signal may also include determining a frequency component of the determined instantaneous power output and determining a flashing light frequency of a flashing light of a vehicle connected as a load based on the determined frequency component.

[0008] Embodiments of the present invention may be implemented with a converter, such as a diode rectifier or a semiconductor switch converter, such as a transistor bridge circuit. The voltage regulator may be a regulator circuit, such as a conventional analog voltage regulator, or may be a voltage regulator implemented by software in a control device. In this case, the control device implementing the voltage regulator and / or the above method steps may be, for example, an engine control device or an ABS control device.

[0009] A computing unit according to the invention, for example a control unit of a motor vehicle, is designed, in particular in terms of programming, to carry out the method according to the invention.

[0010] It is also advantageous to implement the method according to the invention in the form of a computer program or computer program product with program code for executing all method steps, since this results in particularly low costs, in particular when the execution control device is also used for other tasks and is therefore present in any case. Suitable data carriers for providing the computer program are in particular magnetic, optical and electrical memories, such as hard disks, flash memories, EEPROMs, DVDs, etc. It is also possible to download the program via a computer network (Internet, intranet, etc.).

[0011] Further advantages and embodiments of the invention will be apparent from the description and the drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention is schematically illustrated in the drawings based on exemplary embodiments and is described below with reference to the drawings.

[0013] Figure 1 A flow chart showing an exemplary method of the present invention is shown;

[0014] Figure 2 shows the power output of the converter calculated from the output signal according to an embodiment of the present invention; and

[0015] Figure 3a and 3b An exemplary converter-regulator circuit that may be used in accordance with embodiments of the present invention is shown. DETAILED DESCRIPTION

[0016] According to one embodiment of the invention, the output signal of a voltage regulator is monitored, which regulates the output voltage of a generator in a vehicle. In this case, the instantaneous output power can be inferred from the output signal. The basic method flow is Figure 1 ; in step 10 the output signal of the regulator is detected and in step 20 the power output is determined from this output signal. According to step 30, the characteristics of the onboard power system and the connected loads can be inferred by evaluating the output power. Finally, in step 40, one or more of the signals or results from the previous steps can be output to an interface. The detection of the output signal and the evaluation can be performed continuously at fixed intervals or only when required.

[0017] Basically, the task of the voltage regulator is firstly to keep the voltage output to the battery or the onboard power supply of the vehicle substantially constant, that is to say within a predetermined range. The power of the generator depends on the rotational speed and therefore changes continuously during operation. Even if the generator power remains constant (that is to say at the same rotational speed), if it is not regulated, the voltage can rise sharply at the same time as low current consumption and can therefore exceed the predetermined charging voltage of the battery.

[0018] For example, if a load is connected to the system, the current consumption in the onboard power supply system will increase as a result. Therefore, in order to keep the charging voltage relatively constant, the voltage regulator will allow a higher generator power. Therefore, the connected load can be inferred from the control variable, that is, the output signal of the voltage regulator. In the case of few or no loads, the output signal of the voltage regulator is designed so that the power is effectively limited, while in the case of many loads connected to the onboard power supply system, the voltage regulator either increases the generator power or limits the engine power less frequently or not at all, depending on the implementation, so that the generator power is output for a longer time.

[0019] Figure 2The time variation curve 100 of the output power P of the converter is shown as an example, which can be calculated from the output signal of the regulator. In this case, first of all, in the first area 110, no load is connected and only the basic demand of the onboard power supply is taken into account. Then, a phase in the power variation curve can be seen, which now represents a higher call power 120, which can be explained by the connection of the load (for example, the handle heater in this case). As long as the control device that evaluates the output signal of the regulator can also determine which elements or loads are instantly connected, the changed power variation curve can now be assigned to these elements or loads. For this purpose, for example, the control signal to the connected load can be compared with the determined power output accordingly, so that it can be determined, for example, whether the detected connection signal of the first load corresponds to a corresponding change in the power output. Similarly, in addition to the control signal, other values ​​related to the load can also be predetermined or stored, so that it can also be determined whether the power output corresponds to the expected value or deviates from the expected value.

[0020] Then, the flash lamp is connected as a further element, which generates a new segmented area 130 in the power variation curve. In addition, with a sufficient signal sampling frequency, it can be clearly seen that it is a flash lamp with a periodically changing flash power consumption (on / off). Alternatively, the flash lamp can also be identified at its predetermined flash frequency, which can be extracted from the sampled output signal and / or the output power obtained from the output signal, for example, by discrete Fourier transformation (DFT).

[0021] Finally, the shutdown of the load and restoration to the base demand is identified on the power curve in region 140 .

[0022] Different situations can thus be identified based on the output signal measured at the regulator. In general, it can thus be determined, for example, whether the power is within the usual range, for example based on prestored values ​​or by comparison with earlier measured values, or whether the leakage current has increased. Short-term measurements are possible, for example for the purpose of diagnosing the onboard electrical system, or long-term monitoring of the output signal is also possible in order to draw further conclusions therefrom. Thus, for example, it can be determined whether the basic demand or power demand of a certain load increases over time, or whether additional unknown loads are connected to the system. Likewise, defects of the generator or rectifier / converter can be detected.

[0023] Furthermore, the onboard electrical system and the power sources can be optimized by means of these diagnostic possibilities. If the onboard electrical system reaches its maximum power capacity, individual loads can be activated with increased priority via the control device and others, such as the handle heater or the socket, can be switched off. In this way, the system can be operated in a sensible manner with a smaller generator than would otherwise be provided, and the costs of the system can thus be correspondingly reduced.

[0024] The signals thus obtained and evaluated can be output on an interface for diagnosis. Likewise, they can also be used further in a control device for targeted control of the load as described or for further intervention in the onboard power supply system. Here, both the output signal of the regulator and the power output calculated from the regulation signal can be output directly to the onboard power supply system. The result of the evaluation, i.e. the determination of the connected load and its current operating and functional state, can be output accordingly or used further. Other calculations can also be performed, such as the average power of the generator, the power demand of the load at a certain time interval or others.

[0025] For the application of these exemplary methods, various systems can be used which serve as converters and regulators for the vehicle electrical system and in particular for the battery voltage.

[0026] For example, a conventional rectifier-regulator unit with analog components can be used, as in Figure 3a , and the output signal of the voltage regulator 240 of this unit can be transmitted to the control device. The three phases of the generator 200 are connected to diodes 252, which form a rectifier 250 for the three-phase current of the generator. The voltage regulator 240 controls switches, for example, in the form of thyristors 254, which regulate the voltage to the battery 210 and the vehicle electrical system 220 by short-circuiting the individual phases.

[0027] In another embodiment, as in Figure 3b As shown in FIG. 1 , a rectifier circuit or, in general, a converter 260 of any type is combined with a control device 270 in which the voltage regulation is implemented on the software side and which is connected to the input and output of the converter 260 accordingly. In this case, the converter can be, for example, a converter as in Figure 3a 260 (e.g., composed of semiconductor switches such as MOSFET 262), which can be used both as a rectifier and as an inverter for the generator and in Figure 3b The latter makes it possible to achieve partial hybridization of the drive train by using the generator optionally as a motor, since the motor can be switched in as a drive element under certain preconditions.

[0028] In such Figure 3a In the case of a diode rectifier 250 in the generator 200, the power limitation for voltage regulation is usually achieved by means of a thyristor 254, which temporarily short-circuits the individual phases of the generator 200. Alternatively, the rectifier can be temporarily separated, that is, disconnected or open-circuited. The output signal of the voltage regulator thus shows the charging phase and the short-circuit phase of the rectifier (or the charging phase and the open phase of the circuit), so that the power output to the onboard power supply 220 can be determined from a duty cycle between these two options. An equivalent circuit can also be obtained by not using a diode, but using a MOSFET, for example, when using a body diode; even in this case, the voltage regulation can be achieved by means of a short-circuit phase or an open circuit.

[0029] In a similar manner, in the case where the transistor circuit 260 is used as a rectifier and inverter, the regulator 270 will provide an output signal which acts on the transistor circuit 260 so that the rotor angle (Polradwinkel) is changed accordingly; when the rotor angle is positive, the generator operation prevails, while a negative rotor angle induces the engine operation. The engine torque or generator power depends on the rotor angle.

[0030] In general, the output signal actually present at the regulator and also the calculated correlation with the current onboard power system power naturally depends on the type of rectifier or inverter circuit, wherein many variations are possible. The method according to the invention ultimately does not depend on the variable output at the regulator output, as long as the currently required power output to the onboard power system can be inferred from this variable as already described. The detection of the output signal and the evaluation can be carried out continuously at fixed intervals or only when required.

[0031] The control device which evaluates the output signal can be an engine control device of a vehicle, in particular a motor vehicle. However, it is also possible that a separate control device or another control device already present on the vehicle takes over these tasks, such as an ABS control device. The same applies to the design of the voltage regulator in the form of a software-side voltage regulator within a control device; the control device can be identical to the control device which evaluates the signal and consumption characteristic values, or the control devices can be two separate arbitrary control devices. In particular, the voltage regulator can be constructed as part of the engine control device, for example as a logic constructed in the engine control device, wherein the digital control signal is then transmitted to the converter unit via suitable lines, such as the vehicle's cable harness. As an example, if Figure 3aThe rectifier unit in the vehicle can also have an actuator or a switch for short-circuiting, which is controlled by a regulator in a control device (eg an engine control unit), wherein the control signal for the actuator is sent via corresponding lines (eg a cable harness of the vehicle).

Claims

1. A method for onboard power supply system diagnosis by means of a voltage regulator (240, 270), the voltage regulator being designed to regulate the voltage of an onboard power supply system (220) of a vehicle provided by a generator (200) via a converter (250, 260) by outputting an output signal, the method comprising: detecting (10) an output signal of the voltage regulator (240, 270) by a control device, wherein the output signal controls a switch for short-circuiting or disconnecting the converter (250, 260); determining (20) an instantaneous power output (100) to the onboard power supply system (220) based on a duty cycle in an output signal of the voltage regulator (240, 270), wherein the duty cycle in the output signal of the voltage regulator indicates a ratio between a charging phase and a short-circuit phase of the converter; as well as The determined power output (100) is evaluated (30) for diagnosing the onboard power supply system (220) and at least one electrical load connected to the onboard power supply system, wherein defects of the generator (200) or the converter (250, 260) can be identified based on the evaluation.

2. The method according to claim 1, wherein: The evaluation is performed based on information associated with a momentary operating state of at least one electrical load.

3. The method according to claim 2, wherein: The information includes a turn-on signal or a turn-off signal of the load.

4. The method according to claim 2 or 3, wherein: The information includes the power requirements of the load.

5. The method according to any one of claims 2 to 3, wherein: Information associated with the operating state of the at least one electric load is stored in the storage unit.

6. The method according to any one of claims 1 to 3, further comprising: The detected output signal and / or the result value of the evaluation and / or the instantaneous power output (100) are output via an interface (40).

7. The method according to any one of claims 1 to 3, further comprising: determining a frequency component of the determined instantaneous power output (100), and A flashing light frequency of a flashing light of a vehicle connected as a load is determined based on the determined frequency component.

8. The method according to any one of claims 1 to 3, wherein: A rotor angle of the generator (200) is predetermined based on the output signal.

9. The method according to any one of claims 1 to 3, wherein: The voltage regulator (240) is a voltage regulator implemented by software in the control device (270).

10. The method according to any one of claims 1 to 3, wherein the control device is an engine control device or an ABS control device.

11. A computing unit designed to execute all method steps of the method according to any one of claims 1 to 10. 12 . A computer program product comprising a computer program which, when executed on a computing unit, causes the computing unit to execute all method steps of the method as claimed in claim 1 .

13. A machine-readable storage medium having a computer program stored thereon, which, when executed on a computing unit, causes the computing unit to execute all the method steps of the method according to any one of claims 1 to 10.

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