DE102011079321A1 - Method for monitoring electrical components of e.g. electrically powered motor vehicle, involves avoiding usage of frequency band when change of frequency band used for communication of signal in charging line exists - Google Patents

Abstract

A charging station (20) is arranged for charging an energy storage device of motor vehicle (1) through charging line (40). The charging line is electrically connected with motor vehicle and charging station during the charging process. The transmitting/receiving units (12, 22) are provided for processing the signals on charging line at high frequency band. The monitoring of whether the change of frequency band used for communication of signal exists is performed, and the frequency band is not used when change of frequency band used for communication of signal exists.

Description

The invention relates to a method for monitoring electrical components of an electrically operated motor vehicle and / or a charging station, which is electrically connected to the latter via a charging line for the purpose of charging an energy accumulator of the motor vehicle, wherein the motor vehicle and / or the charging station for communication during the charging process include a transmitting / receiving unit, which is adapted to impart signals on the charging line high-frequency and to process.

In the context of the present description, an electrically operated motor vehicle is understood as meaning both a purely electrically operated motor vehicle and a hybrid vehicle, the latter having an internal combustion engine in addition to an electric drive machine.

In electrically powered vehicles often voltages of more than 12 V are used in the electrical system. In the event of a line interruption, an arc can occur over which the current can continue to flow unhindered. If the line is operated with a DC voltage, the arc remains permanently. In this case, the arc becomes more stable and can bridge more distances, the higher the voltage applied to the line. An electric arc can damage not only the line itself but also the surrounding infrastructure. The described problem can not only occur during operation of the motor vehicle, but also when it is connected to a charging station for the purpose of charging its energy store. A line interruption can occur, for example, by a defective charging cable or an incorrect plug connection of the charging cable to the charging station and / or the motor vehicle.

It is an object of the invention to provide a method by which a problem during charging and during operation of an electrically operated motor vehicle can be detected easily and reliably. It is worth object of the invention to provide a device with which a problem when loading and operating an electrically powered motor vehicle can be detected easily and safely.

These objects are achieved by a method according to the features of claim 1 and a transmitting / receiving device according to the features of claim 12. Advantageous embodiments will be apparent from the dependent claims.

The invention provides a method for monitoring electrical components of an electrically operated motor vehicle and / or a charging station, which is electrically connected thereto for the purpose of charging an energy store of the motor vehicle via a charging line. For communication during the charging process, the motor vehicle and / or the charging station comprise a transmitting / receiving unit which is designed to impart high-frequency signals to the charging line and process them. In the method, several frequency bands used or usable for a communication are monitored by the transmitting / receiving unit of the motor vehicle and / or the charging station as to whether a frequency level change deviating from a respective intended communication occurs. When the frequency level change occurs on several of the frequency bands, a hazard situation is concluded.

The operation of an electrically operated motor vehicle is understood to mean both the driving operation and the parked (parking) vehicle both during a charging operation and outside thereof.

The invention is based on the idea that when a fault of electrical components such. As an arc or a spark, a broadband high frequency radiation occurs. The main part of the broadband high frequency radiation is in the AM range from a few kHz to about 30 MHz. In newer electrically powered vehicles and charging stations transmitting / receiving units are provided to increase the efficiency of the charging process. These are based on the principle of so-called powerline communication (PLC) and are designed to impose high-frequency signals on the charging line used for energy transmission. The high-frequency signal components can be processed by the transmitting / receiving unit as part of a communication. In the case of an active (in the sense of switched on) transceiver unit, an electrical spark or arc leads to a frequency level change on all frequency bands used or usable by the transceiver units, which can be detected by the transceiver units. The presence of such frequency level changes on at least two frequency bands can be interpreted as an indication that there is a fault in one of the electrical components of the electric motor vehicle and / or the charging station including the charging line.

In order to be able to realize the monitoring of the electrical components for a danger emanating from sparks or electric arcs, these are transmitted beyond the transceiver units No further hardware components needed. Only a software-side adaptation of the signal processing of the transmitting / receiving units is required. As a result, the method according to the invention can be realized in a simple and cost-effective manner. In particular, countermeasures can be taken after the detection of sparks and / or arc paths, which include, for example, the switching off of affected circuits. Thus damage can be averted from the motor vehicle and the infrastructure.

According to an expedient embodiment of the method according to the invention, a hazard situation is concluded when a frequency level change is detected on all frequency bands used or usable by the transmitting / receiving unit of the motor vehicle and / or the charging station for communication. As already described, a caused by a spark or an arc disturbance of electrical components by a broadband high frequency radiation is noticeable, which is noticeable in virtually all frequency bands of the transmitting / receiving unit. The more such frequency bands are checked by the transmission / reception units provided in the motor vehicle and / or the charging station, the more securely it can be concluded that a hazard exists.

A frequency level change in the sense of the present method is a deviation from a known signature, which occurs in the context of a communication between the motor vehicle and the charging station. Signatures are used by the transceiver units as part of their regular communications. A deviation from the known signatures can therefore already be an indication of the existence of a fault or hazard.

According to a further expedient embodiment, a hazard situation is concluded when the frequency level changes detected on the plurality of frequency bands are detected continuously or at intervals over a predetermined minimum period of time. An uninterrupted change in the frequency level indicates an arc in a DC powered vehicle electrical system. The occurrence of a frequency level change at a regular or irregular time interval could signal, for example, a loose contact, provided that the line having the problem is operated with an alternating voltage. In contrast to a line operated with DC voltage, in the case of a line operated with AC voltage, the arc can break off when the current passes through zero. A repeated occurrence of a high-frequency frequency level change therefore signals z. B. a problem in the contacting in an electrical component.

According to a further expedient refinement, the frequency level change of a respective frequency band is evaluated and includes a comparison of parameters of the currently determined frequency level change with reference parameters stored in a memory of frequency level changes typical of a hazard. For example, limit values for the amplitudes at several frequencies of a frequency band can be stored as reference parameters. The corresponding amplitudes at the given frequencies of a frequency band can be extracted from the signal at the occurrence of the frequency level changes and compared with the reference parameters. As a result, the safety can be increased in the diagnosis of a hazard.

According to a further expedient refinement, the frequency level change of a respective frequency band is evaluated and the combination of several criteria by means of fuzzy logic comprises a result. According to this embodiment, not a single frequency band, but a plurality of frequency bands is evaluated in order to obtain an evaluation result based on their frequency levels with a "fuzzy" logic.

• – Durchführung einer Strommessung. Hier wird überprüft, ob in der überprüften Leitung ein Strom fließt oder nicht. Sofern ein Strom detektiert werden kann, wird dessen Höhe ermittelt.
• – Durchführung einer Spannungsmessung. Für die überprüfte Leitung wird ermittelt, ob an dieser eine Spannung anliegt. Falls ja, wird die Höhe der Spannung ermittelt.
• – Durchführung eines Funktionstests. Hiermit wird überprüft, ob eine entsprechende Komponente ihre bestimmungsgemäße Funktion aufweist oder nicht.
• – Überprüfung, ob die durchgeführten Messungen und/oder Tests eine Abweichung von bekannten und/oder erwarteten Werten oder einer erwarteten Funktion aufweisen.

According to a further preferred refinement, an evaluation of the frequency level changes occurring on a plurality of frequency bands takes place and comprises carrying out a plausibility test before concluding on a hazardous situation. Performing the plausibility test involves one or more of the following steps:

• - Carrying out a current measurement. Here it is checked whether a current flows in the tested line or not. If a current can be detected, its height is determined.
• - Carrying out a voltage measurement. For the checked line, it is determined whether a voltage is applied to this. If so, the magnitude of the voltage is determined.
• - Perform a functional test. This checks whether a corresponding component has its intended function or not.
• - Check whether the measurements and / or tests carried out have a deviation from known and / or expected values or an expected function.

The security of the prognosis regarding a hazard can also be increased by this design.

According to another expedient embodiment, frequency bands are monitored for the occurrence of frequency level changes which are not used by the transceiver units for communication. For this purpose, for example, one or more dedicated frequency ranges can be kept free during the normal data transmission between the motor vehicle and the charging station during a charging process. If evaluable levels and signals appear on or in these frequency ranges during the data transmission, then a critical, hazardous situation can be inferred. In comparison to the monitoring of such frequency bands, which are also used for communication between the motor vehicle and the charging station during a charging process, the diagnosis of the hazard can take place in a shorter time.

According to a further expedient refinement, the frequency level changes in a plurality of frequency bands can be detected in parallel or chronologically one after the other in order to conclude a hazard. Whether the detection of frequency level changes in several frequency bands takes place in parallel or in succession depends essentially on the signal processing logic of the transceiver units used.

In a further expedient embodiment, the hazard to be detected is an arc or a fault in the electrical connection between the charging station and the motor vehicle or within the motor vehicle. Conveniently, the transmitting / receiving unit of the motor vehicle is activated independently of a charging process. Accordingly, the method according to the invention can be carried out not only during a charging process in which the motor vehicle is connected to the charging station via the charging cable and can communicate via the charging cable. Rather, a monitoring of the electrical components during operation of the motor vehicle can take place, as long as the transmitting / receiving unit of the motor vehicle is operated in a "reception mode", although this is not connected to any dedicated communication partner via a line. The broadband high frequency radiation emanating from a fault can then be coupled via electrical lines acting as antennas in the transmission / reception unit of the motor vehicle, so that they can perform the described evaluation.

The invention further provides a transmitting / receiving device, in particular a motor vehicle or a charging station, which is designed to high-frequency impose signals on a line used for energy transmission and process and execute a method as described above.

The invention further comprises a motor vehicle with a transmitting / receiving device according to the invention.

Furthermore, the invention comprises a charging station for charging an energy store of a motor vehicle, which comprises a transmitting / receiving device according to the invention.

The invention will be described in more detail below with reference to an embodiment in the drawing. Show it:

1 a schematic representation in which a motor vehicle is connected via a charging line to a charging station,

2 a schematic representation of a motor vehicle according to the invention,

3 a first schematic representation of a number of frequency bands, which are divided into a number of Segementen, and

4 a second schematic representation of a number of frequency bands, which are divided into a number of Segementen.

1 shows a schematic representation of a charging process of a motor vehicle 1 at a charging station. For the sake of simplicity, only the components required for the method according to the invention are shown.

On the part of the electrically operated motor vehicle 1 These include a charging unit 10 , The loading unit 10 has a transmitting / receiving unit 12 on. This includes a transceiver 13 for sending (Tx) and receiving (Rx) data, one with the transceiver 13 coupled computing unit 14 for processing the received data or for preparing the data to be transmitted as well as a coupler 15 over which the transmitting / receiving unit 12 to a line used to charge an energy store (not shown) 31 is coupled. The administration 31 is between a plug connection 16 and a charge controller 17 the charging unit interconnected.

The charging station 20 correspondingly comprises a transmitting / receiving unit 22 which is a transceiver 23 , one with the transceiver 23 coupled computing unit 24 as well as a coupler 25 for coupling the transmitting / receiving unit 22 to a line 32 the charging station 20 includes. The administration 32 ends at a plug contact 26 the charging station 20 , Between the plug contact 26 and the plug contact 16 of the motor vehicle 1 is one with this z. B. pluggable charging cable 30 arranged over the one in 1 not shown and with the charge controller 17 Connected energy storage by the charging station 20 can be loaded. The components of the charging station necessary for the provision of energy 20 are in for simplicity 1 also not shown.

The in the motor vehicle 1 and the charging station 20 provided transceiver units 12 respectively. 22 allow communication between the motor vehicle 1 and the charging station 20 during the charging process. This allows this energy-efficient and -optimized be performed.

The charging of the energy storage of the motor vehicle 1 takes place - as well as the operation of most of the electrical components of the motor vehicle - using a DC voltage. By way of example only, the charging line 30 as well as the lines 31 and 32 for graphic reasons, therefore, two lines. If a rectifier arrangement is provided in the motor vehicle, the line could 32 as well as the charging line 30 be subjected to AC voltage. In both variants, the method described below is capable of detecting faults occurring in the contacting as well as the electronic components in the motor vehicle and of the charging station and, if necessary, taking appropriate measures to eliminate them until a final remedy. In the following description it is assumed that the in 1 described system is operated with DC voltage or current.

With the reference number 40 is a line break in the charging line 30 characterized. The line interruption 40 can, for example, by mechanical damage to the charging cable 30 be caused.

Is that between the two conductors of the charging line 30 applied voltage more than 12 V, it may be due to the line break 40 come to a spark or arc, which does not tear off by itself due to the DC voltage. The arc is all the more stable and can bridge the more distances the interruption, the higher the voltage between the two conductors. The occurrence of the arc causes a broadband high frequency radiation, the majority in the AM range from a few kHz to about 30 MHz. From this broadband radio frequency radiation results in a frequency level change in more of the transmitting / receiving units 12 respectively. 22 used frequency bands. These frequency level changes in those of the transceiver units 12 and 22 used or usable frequency bands are detected according to the invention in order to conclude from this a problem.

The transceiver units 12 and 22 are based on the so-called Powerline Communication (PLC) technology. In this case, signals are high-frequency to the DC or AC voltage of supply lines, here the charging line 30 between the motor vehicle and the charging station, imprinted. The computing units 14 . 24 have a broadband signal processing, such as amplifiers and signal processing, which can either process multiple frequency bands (G3 or OFDM modulation) or selectively processed individual frequency bands (S-FSK), but these are tuned over a range.

The computing units 14 respectively. 24 the transmitting / receiving units 12 . 22 Conventional PLC modems essentially differ only in performance for digital signal processing. Each arithmetic unit can evaluate at least one frequency with respect to signal curves and signatures. Since the individual applications process either different signatures and / or frequencies, currently available computational units are programmable and configurable to suit different applications. Known PLC modems are, for example, the ST7570 from ST Micro Electronics, the PGA 112 Analog Front End for G3-PLC from Texas Instruments, the TMS320f28235 Microcontroller for G3-PLC from Texas Instruments or the MAXIM G3 PLC.

The frequency level changes caused by an arc or even a spark lead to a significant deviation of the respective arithmetic units 14 . 24 signals to be processed. These frequency level changes noticeable on multiple frequency bands or channels are now interpreted as errors occurring in the system. This is merely an adaptation of the software of the previously used computing units 14 . 24 the transmitting / receiving units required.

In particular, the arithmetic units 14 . 24 configured such that this deviation from a known signature, in the context of communication between the motor vehicle 1 and the charging station 20 occurs as a frequency level change caused by a spark or arc. In order to ensure that it is not just a short-term disturbance, which is, for example, coupled in via radio from outside, it is provided that the frequency level changes detected on the several frequency bands continue beyond a predetermined minimum time duration continuously or at intervals must be detected. The predetermined minimum period of time is preferably more than 100 ms. An uninterrupted frequency level change indicates an arc in a DC powered system. If the frequency level change is detected on the multiple frequency bands at regular or irregular intervals, this may indicate a loose contact in an AC powered system.

It may be provided to deposit the typical signature or signatures of a stationary arc for better and more secure evaluation in a memory of the transmitting / receiving units as a reference curve. Then, a comparison of parameters of the currently detected frequency level change with stored in the memory reference parameters of hazardous for a frequency level changes can be performed. For example, limit values for amplitudes at several frequencies of a frequency band can be used for this purpose.

A particularly simple and rapid detection of a spark or arc occurs when several dedicated frequency ranges are kept free of communication between the motor vehicle and the charging station during normal data transmission. If there are evaluable frequency level changes during data transmission, then a critical situation can be deduced.

The existing signal processing in the arithmetic units 14 . 24 can optionally carry out further plausibility checks. For example, it is possible to check whether a current is flowing in certain line strands and, if so, in what amount. Likewise, a voltage measurement can be performed, whereby voltage and current can be set in relation. Furthermore, alternatively or additionally, a functional check of individual or a plurality of components, in particular of the motor vehicle, can take place in order to determine whether there is a deviation from a known or expected behavior. By means of such plausibility checks, it can also be determined, for example, in which wiring harness a fault occurs. If appropriate switching means are provided, the relevant wiring harness can be disabled. In the in 1 shown configuration, the deactivation can be done either on the part of the motor vehicle or on the side of the charging station.

In another embodiment, an evaluation of the frequency level change of a plurality of frequency bands, wherein a combination of several criteria by means of fuzzy logic to a result occurs. A possible procedure is described below on the basis of 3 and 4 explained. In each of these 12 different frequency bands (so-called frequency carriers) FB1,..., FB12 are shown by way of example. In practice, up to 1155 such carriers are currently in use in PLC. By way of example, four frequency bands each are assigned to a segment "Low Freq", "Mid Freq" or "High Freq".

• a) Festlegen eines einfachen Kriteriums, z. B. Frequenzpegel pro Frequenzband;
• b) Normieren des Kriteriums, hier der Frequenzpegel (z. B. „hoch”, „mittel”, „niedrig”)
• c) Gruppieren der Frequenzänder FB1, ..., FB12 in Bewertungsgruppen, d. h. in die Segmente „Low Freq”, „Mid Freq” oder „High Freq”;
• d) In Bezug setzen der Bewertungsgruppen, d. h. Überprüfung, wieviele Frequenzbänder pro Segment („Low Freq”, „Mid Freq” oder „High Freq”) ein vorgegebenes Kriterium erfüllen;
• e) Entscheidungsfindung, d. h. Ermittlung, ob z. B. alle Segmente einen Wert „hoch” aufweisen, was auf einen Problemfall deutet.

It is now not individual frequency bands alone used for an absolute evaluation, but it is a "fuzzy" logic used for evaluation. For this the following steps are carried out:

• a) Setting a simple criterion, eg. B. frequency level per frequency band;
• b) normalizing the criterion, here the frequency level (eg "high", "medium", "low")
• c) Grouping the frequency edges FB1, ..., FB12 in evaluation groups, ie in the segments "Low Freq", "Mid Freq" or "High Freq";
• d) related to the evaluation groups, ie checking how many frequency bands per segment ("Low Freq", "Mid Freq" or "High Freq") meet a given criterion;
• e) decision-making, ie determination of whether z. B. all segments have a value "high", indicating a problem case.

In the embodiment of 3 For example, the "Low Freq" segment has two frequency bands with a high (FB2, FB3) and two with medium (FB1, FB4) frequency levels. The segment "Low Freq" has according to the predetermined criteria then z. For example, a value of "normal". The "Mid Freq" segment has two frequency bands with high (FB6, FB8) and two frequency bands with low (FB5, FB7) frequency levels. The segment "Mid Freq" also has a value "normal" according to the given criteria. The "High Freq" segment has a frequency band with a high (FB11), two with medium (FB9, FB12) and a frequency band with a low (FB10) frequency level. The segment "High Freq" also has a value "normal" according to the predetermined criteria. After three out of three segments have a value of "normal", there is no problem case.

In the embodiment of 4 For example, the "Low Freq" segment has three frequency bands with high (FB1, FB2, FB3) and one frequency band with a middle (FB4) frequency level. The segment "Low Freq" has according to the predetermined criteria then z. For example, a value of "high". The "Mid Freq" segment has two frequency bands with high (FB6, FB8), one with a middle (FB5) and one frequency band with a low (FB7) frequency level. The segment "Mid Freq" also has a value according to the given criteria "High" on. The High Freq segment has three frequency bands with high (FB9, FB11, FB12) and one frequency band with a medium (FB10) frequency level. The segment "High Freq" also has a value "high" according to the predetermined criteria. After three out of three segments have a value of "high," this example has a problem case.

The difference between the fuzzy logic and the purely digital logic is that the fuzzy logic also contains the middle range ("maybe there is a problem") that does not yet definitively determine a decision. Thus, a weighting after a segment with the value "high" can also take place if all frequency levels are at least "medium" or "high", but not one "low". This behavior depends in detail on how many frequency bands are scheduled per segment. In practice, the grouping and selection of classes depends on the real implementation.

The example in the 3 and 4 assumes that one field strength gets a level as an evaluation criterion per frequency band. In reality this is not absolutely necessary. It is sufficient or possible, other criteria such. B. transmitted information per frequency band, error per frequency band, status bit per frequency band, etc. apply accordingly. The classification can also be based on a similar categorization ("little", "normal", "a lot"). The basis is always that per frequency band a certain frequency and a usable frequency level are needed to obtain the corresponding information. The formation of different segments depends on the existing database and the evaluation carried out.

The procedure according to the invention is thus based on detecting deviations recognized by a normal signal transmission in the context of a communication and of interpreting them as a fault. Especially in such communication methods as OFDM, which evaluate multiple frequency bands and use communication channels, the massive, simultaneous disturbance of the frequency band or channel can be used as an indicator of a spark or arc.

An advantage of the method is that the electronics used using conventional powerline communication technology either directly the critical cable to be monitored and the plug used and thereby necessary connections directly in contact with the communication system, which now acts as a monitoring system stands. A detour via an antenna and possibly a faulty coupling of other disturbances is not required.

The procedure according to the invention can also be used in the pure driving mode of the electrically operated motor vehicle 1 be used. This is schematically in 2 shown. In this be next to the vehicle-side charging unit 10 an electric motor 2 and a battery 3 shown, the battery 3 to the charge controller 17 connected. For example, as in 2 with the reference number 40 illustrates a disturbance between the energy storage 3 and the electric motor 2 on, so this leads to a broadband high frequency radiation. Provided that the transmitting / receiving unit 12 is also actively operated during the pure driving despite lack of communication partner, this broadband radio frequency radiation by the computing unit 14 the transmitting / receiving unit 12 be detected. The coupling of the broadband high frequency radiation is in this case not only on the lines shown, but also via radio.

Claims (14)

Method for monitoring electrical components of an electrically driven motor vehicle ( 1 ) and / or a charging station ( 20 ) for the purpose of charging an energy store of the motor vehicle ( 1 ) with this via a charging line ( 40 ) is electrically connected, wherein the motor vehicle ( 1 ) and / or the charging station ( 20 ) for a communication during the charging process, a transmitting / receiving unit ( 12 . 22 ), which is adapted to send signals to the charging line ( 40 ) high-frequency impose and process, in which - by the transmitting / receiving unit ( 12 . 22 ) of the motor vehicle ( 1 ) and / or the charging station ( 20 ) monitoring a plurality of frequency bands used or usable for a communication as to whether a frequency level change deviating from a respective intended communication occurs; and - when the frequency level change occurs on more than one of the frequency bands, a hazard situation is inferred. Method according to Claim 1, in which a hazardous situation is concluded when, on all of the transmission / reception unit (s) ( 12 . 22 ) of the motor vehicle ( 1 ) and / or the charging station ( 20 ) a frequency level change is detected for a frequency band used or usable for communication. Method according to one of the preceding claims, in which a frequency level change is a deviation from a known signature, which in the context of a communication between the motor vehicle ( 1 ) and the charging station ( 20 ) occurs. Method according to one of the preceding claims, in which it is concluded that a risk situation exists if the frequency level changes detected on the plurality of frequency bands are detected continuously or at intervals over a predetermined minimum period of time. Method according to one of the preceding claims, in which an evaluation of the frequency level change of a respective frequency band takes place and a comparison of parameters of the currently detected frequency level change with stored in a memory reference parameters of typical for a hazard frequency level changes. Method according to one of the preceding claims, in which an evaluation of the frequency level change of a respective frequency band takes place and the combination of several criteria by means of fuzzy logic to a result. Method according to one of the preceding claims, in which an evaluation of the frequency level changes occurring on a plurality of frequency bands takes place and the execution of a plausibility test is carried out before a hazardous situation is concluded, wherein the performance of the plausibility test comprises one or more of the following steps: - carrying out a current measurement; - performing a voltage measurement; - carrying out a functional test; - Check whether the measurements and / or tests carried out have a deviation from known and / or expected values or function. Method according to one of the preceding claims, in which frequency bands are monitored for the occurrence of frequency level changes which are detected by the transceiver units ( 12 . 22 ) are not used for communication. Method according to one of the preceding claims, in which the frequency level changes in a plurality of frequency bands can be detected in parallel or in succession in order to conclude a hazard. Method according to one of the preceding claims, in which the risk to be detected is an arc or a fault in the electrical connection between the charging station ( 20 ) and the motor vehicle ( 1 ) or within the motor vehicle ( 1 ). Method according to one of the preceding claims, in which, independently of a charging process, the transmitting / receiving unit ( 12 . 22 ) of the motor vehicle ( 1 ) is activated. Transmitting / receiving device, in particular an electrically operated motor vehicle ( 1 ) or a charging station ( 20 ), which is adapted to high-frequency impose signals on a line used for the transmission of energy and process and to carry out a method according to one of the preceding claims. Electrically operated motor vehicle, comprising a transmitting / receiving device according to claim 12. Charging station for an electrically operated motor vehicle, comprising a transmitting / receiving device according to claim 12.

Images