Method and apparatus for determining alternator functionality

Abstract

An apparatus for generating electrical energy comprises an alternator (2) having a rotor (3) with windings (4) for being magnetized by current fed thereto and a stator (5) with at least three stator windings (6-8) for generating a three-phase voltage therein upon rotation of the magnetized rotor in the stator. A rectifier (9) has inputs connected to the stator windings. An apparatus (16) is configured to measure a change over time of a difference of two of said phase voltages and an evaluation unit (18) is configured to evaluate the result of this measurement to determine a functioning of the alternator (2). A control unit (13) located remote from the alternator (2) controls the rotor current.

Description

Technical Field

[0001] This invention relates to a device for generating electrical energy, the device comprising an alternator having

[0002] • A rotor configured to be connected to a mechanical energy source for rotation, and the rotor being provided with windings for being magnetized by a current fed therein.

[0003] • A stator that surrounds a rotor and has at least three stator windings for generating at least three-phase voltages in these windings when the magnetized rotor rotates therein.

[0004] • A rectifier having an input connected to the stator windings and configured to convert the phase voltage into a DC voltage output by an AC generator.

[0005] The device also includes a control unit, and a method according to the preamble of the appended independent method claim, the control unit being located remotely from the alternator and configured to control the alternator by controlling the rotor current flowing through the rotor windings.

[0006] As an example, such a device can connect the rotor of an alternator to the mechanical power source of a motor vehicle or in an industrial application. The following discussion will primarily focus on the first of these two examples to illustrate the invention and the problem it addresses, rather than limiting the invention in any way.

[0007] The advantages of moving the control unit (i.e., the hardware associated with alternator control, including rotor current control) out of the alternator rather than including it within the alternator are multifaceted. Because there is no electronics inside the alternator limiting the permissible temperature range, the permissible temperature range of the alternator is increased. Another advantage is the simplification of alternator design and the achievement of inherent current isolation between alternator control and alternator output, thereby increasing system robustness.

[0008] However, it is desirable to be able to determine the function of the alternator in order to detect faults within or connected to the equipment, thereby protecting the components of the equipment and / or detecting any parts that must be replaced. Background Technology

[0009] US 2013 / 0187447 describes a device of the type defined in the introduction capable of performing a type of diagnostic on an alternator included therein, but such diagnostics requires the presence of multiple alternators and one of them to be switched off. Therefore, in the case of a device containing only a single alternator, diagnostics for determining the function of its alternator cannot be performed using the methods disclosed therein. Summary of the Invention

[0010] The object of the present invention is to provide an apparatus and method of the type defined in the introduction, which improves upon known apparatuses by addressing the aforementioned problems.

[0011] This objective is based on the arrangement obtained according to the invention relative to a device having the features listed in the characterizing portion of the appended claim 1.

[0012] Therefore, the device includes means configured to measure the change in the difference between two phases of the phase voltage connected to the rectifier input over time, and an evaluation unit configured to evaluate the result of the measurement to determine the function of the alternator. This means that diagnostics aimed at determining the function of the alternator can be performed efficiently without having more than one alternator for this purpose, although within the scope of the invention, the device according to the invention includes more than one alternator. It has been found that by measuring the change in the difference between two phases of the phase voltage over time, a robust system is obtained that provides reliable measurement results for determining the function of the alternator and is less affected by various disturbances. Furthermore, the results of such measurements will constitute a reliable indication of the function of the alternator.

[0013] According to an embodiment of the present invention, the evaluation unit is configured to send the evaluation result to the control unit, which is configured to control the rotor current and the current of the alternator based on the evaluation result. This means that the alternator can be controlled by controlling the rotor current based on the evaluation result.

[0014] According to another embodiment of the invention, the evaluation unit and the control unit are included in the same electronic control unit configured to control the alternator.

[0015] According to another embodiment of the invention, the evaluation unit is configured to compare the change in the measured difference between two-phase voltages over time with the change in a reference value of that voltage difference over time, and the control unit is configured to control the rotor current flowing through the rotor windings to keep the measured voltage difference below a predetermined value, which is higher than the reference voltage difference. This ensures that the rotor current can never increase to such a high level that components of the alternator (e.g., diodes in the rectifier) ​​would be damaged.

[0016] According to another embodiment of the invention, the evaluation unit is configured to compare the measured change in the difference between two-phase voltages over time with the expected change in the voltage difference over time of the actual rotor current flowing through the rotor windings, and to determine that functional degradation of the alternator is detected when the deviation between the measured voltage difference and the expected voltage difference is at least a predetermined amount. In this way, functional degradation of the alternator (e.g., a damaged cable connected to the alternator's output, such as a battery) can be detected, thereby protecting alternator components that might otherwise be damaged.

[0017] According to another embodiment of the invention, the evaluation unit is configured to compare the occurrence of a change in the measured difference between two-phase voltages over time with the occurrence of a sine curve to detect potential defects in components of the rectifier. Where defects are present, the need to replace rectifier components can be reliably detected in this manner.

[0018] According to another embodiment of the invention, the rotor is configured to be connected to a mechanical power source of a motor vehicle. This device is particularly suitable for this application.

[0019] According to another embodiment of the invention, the rotor is configured to be connected to a mechanical energy source in an industrial application, which is another possible suitable application of the device according to the invention.

[0020] The object of this invention relates to a method obtained by providing a method having the features listed in the appended independent method claims. Its advantages become apparent from the above discussion of the apparatus of the invention and its embodiments.

[0021] The present invention also relates to uses of a motor vehicle, computer program, computer program product, electronic device control unit, and arrangement according to the appended claims, which are respectively directed to a motor vehicle, computer program, computer program product, electronic device control unit, and application.

[0022] Other advantages and beneficial features of the invention will become apparent from the following description. Attached Figure Description

[0023] Referring to the accompanying drawings, the following is a detailed description of an embodiment of the present invention cited as an example.

[0024] In the attached diagram:

[0025] Figure 1 This is a schematic diagram illustrating a device according to an embodiment of the present invention.

[0026] Figure 2 and Figure 3 yes Figure 1 The graph shows the relationship between the two-phase voltage difference of the alternator in the device and the time of two different faults related to the device.

[0027] Figure 4 This is a flowchart illustrating the steps performed by the method according to an embodiment of the present invention, and

[0028] Figure 5 This is a schematic diagram illustrating an electronic device control unit for implementing the method according to the present invention. Detailed Implementation

[0029] Figure 1 A device for generating electrical energy according to an embodiment of the present invention is shown schematically. The device is arranged inside a motor vehicle 1 and includes an alternator 2 having a rotor 3 configured to be connected to a mechanical energy source (e.g., shaft 19 of a vehicle engine) for rotation. The rotor 3 is provided with windings 4 for being magnetized by a current fed therein. The alternator also has a stator 5 surrounding the rotor 3, although for the sake of simplicity of description and explanation of the invention... Figure 1 The stator 5 is not shown in this manner, and it has three stator windings 6-8 for generating three-phase voltages U, V, and W in these windings when the magnetized rotor rotates therein. The alternator also has a rectifier 9 with an input 17 connected to the stator windings 6-8, and is configured to convert the phase voltages U, V, and W into DC voltages on the alternator output 10, represented here by two cables 11 and 12 connected to one or more batteries in the vehicle. The rectifier 9 may consist only of rectifier diodes, without requiring control of the rectifier or connecting it to a separate control unit for active rectification operation.

[0030] The device also includes a control unit 13, which is configured to control the alternator 2 by controlling the rotor current flowing through the rotor windings. The control unit 13 is included in an electronics control unit 14 located remotely from the alternator 2, so that the electronics of the control unit 13 are not considered when determining the maximum permissible temperature within the alternator. The control unit 13 controls the rotor current by sending a PWM (Pulse Width Modulation) signal to a so-called driver 15, which sends current to the rotor windings 4 according to the presence of the PWM signal.

[0031] The device also includes a device 16 configured to measure the change over time of the difference between two phases of the phase voltage connected to the input 17 of the rectifier 9 by connecting two phases of the phase voltage (V and W in this case) to the measuring device 16. The measuring device sends the measurement result to an evaluation unit 18, which is configured to evaluate the measurement result to determine the function of the alternator 2. The evaluation unit 18 and the control unit 13 are included in the same electronic control unit 14 configured to control the alternator, and the evaluation unit is configured to send the evaluation result to the control unit 13, which is configured to control the rotor current and the alternator current based on the evaluation result.

[0032] The evaluation unit is configured to compare the change in the measured difference between the two-phase voltages V and W over time with the change in a reference value of that voltage difference over time. The evaluation unit is further configured to compare the measured difference U between the two-phase voltages. VW The voltage difference U between the actual rotor current flowing through the rotor winding and the time-varying rotor current. E The changes over time are compared, and the voltage difference U measured is determined. VW With the expected voltage difference U E When the deviation is at least a predetermined amount, functional degradation of the alternator is detected.

[0033] Figure 2 This illustrates the voltage difference U when cables 11 and 12 on the output of alternator 10 (e.g., a battery) are damaged. VW What would happen is that the voltage difference would be higher than expected. Such damage or breakage of the cable would cause a significant increase in resistance in the electrical system to which the device is connected, and subsequently, control unit 13 would increase the rotor current to handle the new "load." Allowing the alternator to generate as high a voltage as required would damage components within the alternator. However, this is avoided by the fact that the evaluation unit will detect this functional degradation of the alternator through the comparison, and control unit 13 is configured to control the rotor current flowing through the rotor windings to maintain the measured voltage difference U. VW The value is lower than the predetermined value, which is higher than the reference voltage difference U. E .

[0034] Evaluation unit 16 is also configured to compare the occurrence of the time-varying difference between the measured two-phase voltages V and W with the occurrence of a sine curve to detect potential defects in rectifier components, since diode failure will result in a voltage difference U VW The relationship with time t deviates from the sine curve, such as Figure 3 As shown.

[0035] Figure 4A flowchart of a method for determining the function of an alternator in a vehicle, according to the present invention, is shown. The method begins with step S1, which measures the change in the difference between the phase voltages V and W of the alternator over time. The measurement results are then evaluated in step S2, and the alternator's function is determined in step S3. These steps are repeated, preferably continuously during alternator operation, to detect potential faults in or connected to the alternator as quickly as possible.

[0036] Computer program code for implementing the method according to the invention is advantageously included in a computer program that can be read into the internal memory of a computer, such as the internal memory of a control unit for electronic equipment in a motor vehicle. Such a computer program is advantageously provided as a computer program product comprising a data storage medium that can be read by a computer and has the computer program stored thereon. The data storage medium is, for example, an optical data storage medium in the form of a CD-ROM, DVD, etc.; a magnetic data storage medium in the form of a hard disk, floppy disk, magnetic tape, etc.; or a flash memory or a memory of the type ROM, PROM, EPROM, or EEPROM. Figure 5 An electronic device control unit 14 is shown schematically, including an execution device 20 (e.g., a central processing unit (CPU) for executing computer software). The execution device 20 communicates with a memory 21 (e.g., RAM type, via a data bus 22). The control unit 14 also includes a non-transitory data storage medium 23, for example, in the form of flash memory or a memory of the ROM, PROM, EPROM, or EEPROM type. The execution device 20 communicates with the data storage medium 23 via the data bus 22. The computer program includes computer program code for implementing the method according to the invention, for example, according to... Figure 4 The computer program code in the illustrated embodiment is stored on the data storage medium 23.

[0037] The present invention is by no means limited to the embodiments described above, as many possibilities for modification thereto will be apparent to those skilled in the art without departing from the scope of the invention as defined by the appended claims.

[0038] In addition to windings, the rotor can also be equipped with permanent magnets, which can improve the efficiency of the AC generator. However, the control is still electric by controlling the current fed into the rotor windings.

[0039] Alternating current generators can have more than three phases, which has the advantage of reducing the ripple of the DC voltage generated by the rectifier. However, more phases will increase the complexity of the alternating current generator.

Claims

1. A device for generating electrical energy, comprising an alternator (2), said alternator (2) having The rotor (3) is configured to be connected to a mechanical energy source (19) for rotation, and the rotor (3) is provided with windings (4) for being magnetized by a current fed therein. Stator (5), which surrounds the rotor and has at least three stator windings (6-8) for generating at least three-phase voltages (U, V, W) in these windings when the magnetized rotor (3) rotates therein. A rectifier (9) having an input (17) connected to the stator windings (6-8) and configured to convert the phase voltage into a DC voltage at the output (10) of the alternator (2). The device also includes a control unit (13) located remotely from the alternator (2) and configured to control the alternator by controlling the rotor current flowing through the rotor winding (4); Its features are, The device also includes Device (16), configured to measure the time-varying difference between two phases (V, W) of the phase voltage connected to the input (17) of the rectifier (9), and Evaluation unit (18), configured to evaluate the results of the measurements to determine the function of the alternator (2); The evaluation unit (18) is configured to measure the difference (U) between the two phase voltages. VW The appearance of the change over time is compared with the appearance of the sine curve to detect possible defects in the components of the rectifier (9).

2. The device according to claim 1, characterized in that, The evaluation unit (18) is configured to send the evaluation result to the control unit (13), which is configured to control the rotor current and the current of the alternator (2) based on the evaluation result.

3. The device according to claim 1 or 2, characterized in that, The evaluation unit (18) and the control unit (13) are included in the same electronic control unit (14) configured to control the alternator (2).

4. The device according to claim 1 or 2, characterized in that, The evaluation unit (18) is configured to measure the difference (U) between the two phase voltages. VW The change over time and the reference value of the voltage difference (U) E The voltage difference is compared over time, and the control unit (13) is configured to control the rotor current flowing through the rotor winding (4) to keep the measured voltage difference below a predetermined value, which is higher than the reference value (U). E ).

5. The device according to claim 4, characterized in that, The evaluation unit (18) is configured to measure the difference (U) between the two phase voltages. VW The voltage difference (U) between the change of the rotor current over time and the expected voltage difference of the actual rotor current flowing through the rotor winding (4). E The changes over time are compared, and the measured voltage difference (U) is determined. VW ) and the expected voltage difference (U) E When the deviation of the alternator (2) is at least a predetermined amount, functional degradation of the alternator (2) is detected.

6. The device according to claim 1, characterized in that, The rotor (3) is configured to be connected to the mechanical energy source of the motor vehicle (1).

7. The device according to claim 1, characterized in that, The rotor (3) is configured to be connected to mechanical energy in industrial applications.

8. A motor vehicle, characterized in that, The motor vehicle is equipped with the device according to any one of claims 1-5.

9. Use of a device according to any one of claims 1-5 in generating electrical energy in a motor vehicle (1).

10. A method for determining the function of an alternator (2), the alternator (2) having The rotor (3) is configured to be connected to a mechanical energy source (19) for rotation, and the rotor (3) is provided with windings (4) for being magnetized by a current fed therein. Stator (5), which surrounds the rotor and has at least three stator windings (6-8) for generating at least three-phase voltages (U, V, W) in these windings when the magnetized rotor (3) rotates therein. A rectifier (9) having an input (17) connected to the stator windings (6-8) and configured to convert the phase voltage into a DC voltage at the output (10) of the alternator (2). The alternator is included in a device for generating electrical energy, and the device also includes a control unit (13) located remotely from the alternator (2) and configured to control the alternator by controlling the rotor current flowing through the rotor winding (4). Its features are, The difference between the two phases (V, W) of the phase voltage connected to the input (17) of the rectifier (9) is measured over time, and The function of the alternator (2) is determined by evaluating the results of the measurements; The difference between the measured two-phase voltages (U) VW The appearance of the change over time is compared with the appearance of the sine curve to detect possible defects in the components of the rectifier (9).

11. A computer program product comprising a non-transitory data storage medium readable by a computer and storing computer program code thereon for implementing a computer program for determining the function of an alternator according to claim 10.

12. An electronic equipment control unit (14) for a motor vehicle, comprising an actuator (20), a memory (21), and a non-transitory data storage medium (23), the memory (21) being connected to the actuator, the non-transitory data storage medium (23) being connected to the actuator (20), and storing on the non-transitory data storage medium (23) computer program code for implementing a computer program for determining the function of an alternator according to claim 10.

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