DE102010055922A1 - Monitoring apparatus for monitoring high-voltage onboard network, has evaluation unit to provide warning signal or switch off onboard network, when value of fault current flowing in onboard network exceeds preset values, respectively - Google Patents

Abstract

The monitoring apparatus has sensor unit (11) to detect fault current in high-voltage onboard network (10), and to output an output value corresponding to detected fault current. An evaluation unit (12) compares output value with preset values, so as to determine whether the output value exceeds the preset values. A warning signal is outputted when output value exceeds one preset value, and high-voltage onboard network is switched off when output value exceeds another preset value.

Description

The invention relates to a motor vehicle monitoring device according to the preamble of claim 1.

From the WO 2006/058824 A2 is already a motor vehicle monitoring device for monitoring a high-voltage vehicle electrical system, with at least one sensor unit which is provided to determine an occurring fault current in the high-voltage vehicle electrical system and output an output value, and with an evaluation unit which is intended, when the output value is exceeded by a limit value, trigger a shutdown mode known.

The invention is in particular the object of providing a structurally simple vehicle monitoring device. It is achieved according to the invention by the features of claim 1. Further embodiments emerge from the subclaims.

According to the invention, a motor vehicle monitoring device for monitoring a high-voltage vehicle electrical system during a charging process, with at least one sensor unit which is provided to determine an occurring fault current in the high-voltage vehicle electrical system and output an output value, and with an evaluation unit, are deposited on the at least two limit values and the it is proposed to trigger a warning mode when the output value is exceeded above the first limit value and to trigger a switch-off mode when the output value is exceeded above the second limit value. As a result, it is possible in particular to dispense with other expensive and heavy safety devices, such as a separating transformer, which in particular makes it possible to provide a structurally simple motor vehicle monitoring device. A "high-voltage on-board electrical system" is to be understood in particular as a cable harness of an electric motor vehicle which is designed for a voltage of more than 60 volts, preferably of over 600 volts. A "fault current" is to be understood here in particular as meaning an electrical current which flows through a damaged insulation or the like from one electrical conductor into another electrical conductor, thereby causing a short circuit. In this case, a fault current can be both an AC fault current and a DC fault current. By "determining" is meant in particular a quantification of the fault current. By "quantification" is meant in particular a determination of the magnitude of the fault current. By "provided" is intended to be understood in particular specially programmed, designed and / or equipped. In this case, an "output value" should be understood to mean, in particular, an electrical and / or electronic signal. An "evaluation unit" is to be understood in particular as meaning a control unit which is designed as part of a control and / or regulating unit. In this case, a "charging process" is to be understood as meaning, in particular, a process in which the battery device is charged via an external power source, for example via an ordinary mains connection in the household electronics. In this case, the charging unit is connected, for example, via a cable to the mains connection of the household electronics.

It is further proposed that the output value of the sensor unit is intended to change with the strength of a fault current. As a result, the evaluation unit advantageously react differently to different fault currents. A "magnitude of the fault current" should be understood to mean, in particular, a magnitude of the fault current in the unit ampere.

It is also proposed that the sensor unit comprises an RCM element. As a result, the fault current can be quantified particularly easily. An "RCM element" should be understood to mean, in particular, an electronic component which, for the detection of a fault current, determines a sum of the currents from all the connected conductors and outputs a value of a fault current.

It is further proposed that the first limit defines a low fault current. As a result, a small fault current can be detected in a particularly advantageous manner and a warning signal can thereby be output to the operator, in particular before the charging process is interrupted. A "low fault current" is to be understood as meaning a fault current of 2 mA, preferably 3 mA, and in a particularly advantageous embodiment 5 mA. A higher fault current, which is set by the second limit, is 10 mA, preferably 20 mA and in a particularly advantageous embodiment 30 mA.

Furthermore, it is proposed that the motor vehicle monitoring device has a control and / or regulating unit which is provided for executing the warning mode and the shutdown mode. As a result, the warning mode and the shutdown mode can be carried out particularly easily. A "control and / or regulating unit" is to be understood in particular as a unit having at least one control unit. A "control unit" is to be understood in particular as meaning a unit having a processor unit and a memory unit as well as an operating program stored in the memory unit. In principle, the control and / or regulating unit can have a plurality of interconnected control units, which are preferably provided to communicate via a bus system, such as in particular a CAN bus system with each other.

It is also proposed that the control and / or regulating unit is provided to execute the warning mode when the evaluation unit determines that the output value has exceeded the first limit value and triggers the warning mode. As a result, an operator can advantageously be informed about a detected fault current.

In addition, it is proposed that the control and / or regulating unit is provided in the warning mode to output a warning signal to a driver / operator. This can advantageously warn a driver / operator that a fault current is occurring in the high-voltage vehicle electrical system before the fault current becomes too large and can then cause damage. A "warning signal" is to be understood in particular as meaning a visual and / or acoustic signal which can be output to the operator via a display and / or signaling device provided for this purpose.

Furthermore, it is proposed that the control and / or regulating unit is provided to execute the switch-off mode if the evaluation unit determines that the output value has exceeded the second limit value and triggers the warning mode. As a result, a possibly dangerous operating state can be advantageously recognized and appropriate measures introduced.

It is also proposed that the control and / or regulating unit is provided in the shutdown mode to interrupt a circuit in the high-voltage vehicle electrical system and so cancel a charging process. As a result, a faulty and possibly dangerous operating state can be advantageously ended. In this context, "interrupting a charging process" should be understood in particular to mean that a power supply to the charging unit is interrupted by interrupting a circuit.

In a particularly advantageous embodiment, the motor vehicle monitoring device has a further first limit value, which is designed as a slope of the fault current between at least two charging operations. As a result, a fault current which progressively amplifies over a plurality of charging processes can in particular be advantageously recognized, and a possible fault in the high-voltage vehicle electrical system can be detected at an early stage. A "slope of the fault current" should be understood to mean, in particular, a difference between at least two fault currents measured in at least two successive charging operations. The further first limit value for the slope of the fault current is preferably at a gradient of 2%, preferably at a gradient of 5% and particularly advantageously at a gradient of 10%, starting from the fault current respectively measured in the previous charging process.

In addition, it is proposed that the high-voltage vehicle electrical system has an inverter unit which is provided to convert an injected alternating current into a charging current in the charging process. As a result, a high-voltage vehicle electrical system with a low number of components can be provided in a particularly advantageous manner, since in particular the charging process can take place via electronics required for a driving operation.

Furthermore, it is proposed that the motor vehicle monitoring device has an electric motor which comprises at least one motor coil, which is provided as an inductance for the charging process. As a result, the high-voltage vehicle electrical system can be made particularly advantageous since additional inductances for a charging process can be dispensed with.

Further advantages emerge from the following description of the drawing. In the drawings, an embodiment of the invention is shown. The drawings, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

Showing:

1 a schematic representation of a drive train of an electric motor vehicle with a motor vehicle monitoring device according to the invention and

2 a schematic representation of a high-voltage vehicle electrical system with the motor vehicle monitoring device according to the invention.

The 1 and 2 show a drive train shown schematically 17 an electric motor vehicle with a motor vehicle monitoring device according to the invention. The powertrain 17 includes an electric motor 18 which is provided for driving the electric motor vehicle. To provide various transmission ratios, the powertrain 17 a transmission device 19 on. By means of the transmission device 19 can be between an input shaft 20 and an output shaft 21 the transmission device 19 different ratios are provided. For this purpose, the transmission device 19 various, not shown gear pairs on. The different gear pairings can be switched via several actuators, not shown. In this case, a torque via at least one pair of gears from the input shaft 20 on the output shaft 21 transfer. The transmission device 19 is automated. In principle, it is also conceivable that the transmission device 19 includes one or more planetary gear sets connected in series to provide the various gear ratios. In principle, it is also conceivable that the drive train 17 no gear device 19 has and a drive torque directly from the electric motor 18 is transmitted without further translation to the drive wheels. In principle, it is also conceivable that drive wheels of the electric vehicle each have a separate electric motor, which are connected directly to the respective drive wheel.

The motor vehicle monitoring device has a control and regulation unit 14 on. The control unit 14 regulates the electric motor 18 , Furthermore, the control unit 14 provided a switching signal for switching the transmission device 19 issue. The control unit 14 controls with the output switching signal, the actuators of the transmission device 19 , This allows different gears in the transmission device 19 be switched.

The motor vehicle monitoring device has a high-voltage vehicle electrical system 10 on. The high voltage on-board network 10 forms an electrical part of the drive train 17 and connects a battery device 15 and a loading unit 16 the motor vehicle monitoring device. At the high voltage on-board network 10 are in an operating state voltages of over 60 volts. The conductors and components of the high-voltage on-board electrical system 10 are accordingly designed and intended to withstand voltages of over 60 volts up to 600 volts and above. The high voltage on-board network 10 has at least in part on a multi-core wiring, which is intended to transmit a three-phase current. The multicore cabling has a first conductor for the first phase of the three-phase current, a second conductor for a second phase of the three-phase current and a third conductor for a third phase of the three-phase current. In addition, the multi-core cabling includes a neutral conductor.

The electric motor 18 is in the high voltage onboard network 10 arranged. The electric motor 18 has three motor coils. The motor coils are arranged in a star configuration. The electric motor 18 has a star point where all motor coils are brought together. The star point is designed as a central connection point. The three motor coils are electrically symmetrical with respect to the neutral point. In principle, however, it is also conceivable that the motor coils are arranged in a parallel arrangement.

To convert an alternating current into a direct current and vice versa, the high-voltage vehicle electrical system includes 10 an inverter unit. The inverter unit is formed by means of three half-bridges not shown in detail. Each of the three half bridges is electrically connected to one of the motor coils of the electric motor 18 connected. In a driving mode, the inverter unit generates from a DC voltage of the battery device 15 an alternating voltage. The AC voltage generated by the inverter unit defines a power that the electric motor 18 emits. In addition, via the AC voltage is a speed, that of the electric motor 18 has, adjustable. The AC voltage is as a three-phase current to the motor coils of the electric motor 18 at.

In the generator operating mode, the inverter unit converts the from the electric motor 18 generated AC voltage to a DC voltage. The inverter unit acts as a boost converter, that of the electric motor 18 provided AC voltage in a higher DC voltage converts. In principle, however, the inverter unit can also be operated without a step-up operation. The DC voltage in which the inverter unit that from the electric motor 18 converted AC voltage causes a charging of the battery device 15 ,

In addition to the high-voltage on-board electrical system 10 The electric motor vehicle comprises a low-voltage on-board electrical system, which has voltages of up to 48 volts. The low-voltage electrical system is intended to provide electrical components, such as the lighting of the electric motor vehicle, with electricity.

The battery device 15 stores an electrical energy with which the electric motor 18 is drivable. The battery device 15 is in a charging process by means of a charging unit 16 loaded. In the charging process, the battery device 15 over the loading unit 16 connected to an external power grid. For this purpose, the loading unit 16 a plug element 22 on, which is intended to be connected mechanically separable with a plug element of the external power system. The loading unit 16 also includes a four-wire cabling, the four conductors 23 . 24 . 25 . 26 , a ladder 23 . 24 . 25 for each one phase of the three-phase current and a zero conductor 26 , having. The loading unit 16 is part of the high voltage on-board electrical system 10 and directly to the high-voltage electrical system 10 connected.

The three-phase current is conducted via a conductor into one of the three motor coils. This is indicated by the high-voltage on-board electrical system 10 a switching unit, the separates the starting point and allows a connection of a conductor to a motor coil. The three-phase current is conducted into the three motor coils, which serve as inductors in the charging process. The inverter unit converts the three-phase current into a direct current for charging the battery device 15 , At the same time, the inverter unit reduces a voltage provided by the external power supply to a voltage that charges the battery device 15 is needed, which is at about 120 volts.

In principle, it is also conceivable that a rectification of the three-phase current of the external power network can be carried out in a direct current in a separate rectifier unit, which is connected upstream of the inverter unit. As a result, the direct current generated by the rectifier unit can be passed through the neutral point in the three motor coils, which serve as inductors in the charging process. The inverter unit is thereby provided in the charging process exclusively for reducing the voltage. The second phase of the DC current is guided past the motor coils directly into the inverter unit.

For monitoring the high-voltage vehicle electrical system 10 During the charging process, the motor vehicle monitoring device comprises a sensor unit 11 , The sensor unit 11 is intended to be a fault current occurring in the high-voltage vehicle electrical system 10 to determine and output an output value. The sensor unit 11 is immediately after the plug element 22 the loading unit arranged. For detecting a fault current, the sensor unit comprises 11 an RCM element 13 , The RCM element 13 is intended to control the currents of all conductors 23 . 24 . 25 . 26 to sum up a ladder strand. The RCM element 13 is designed as a coil, all conductors 23 . 24 . 25 . 26 the loading unit 16 encloses. The ladder 23 . 24 . 25 . 26 through the RCM element formed as a coil 13 are guided, generate in an operating state in which they carry a current, an electro-magnetic field around. This allows the ladder 23 . 24 . 25 . 26 by the electro-magnetic field they generate, a voltage in the coil-shaped RCM element 13 induce. Because all leaders 23 . 24 . 25 including the zero conductor 26 by the RCM element designed as a coil 13 are in a normal operating state, a sum of the currents in the four conductors 23 . 24 . 25 . 26 equal and thus the induced voltage in the coil equals zero. Flows through a faulty operating state during charging at any point of the high-voltage vehicle electrical system 10 a current across an unwanted path is the sum of the currents in the four conductors 23 . 24 . 25 . 26 nonzero and a voltage in the coil-shaped RCM element 13 induced. A sum of all currents is equal to zero in a fault-free operating state. If a fault current occurs, the sum of the currents is not equal to zero. The output value is the RCM element 13 a level of fault current during the charging process in the high-voltage vehicle electrical system 10 occurs.

For evaluation of the sensor unit 11 provided output value, the motor vehicle monitoring device has an evaluation unit 12 on. The evaluation unit 12 is integral with the control unit 14 educated. The evaluation unit 12 can in principle be designed as a stand-alone controller. The coil of the RCM element 13 is with the evaluation unit 12 connected. The output value of the RCM element 13 is a stream coming from the evaluation unit 12 is evaluated. In principle, it is also conceivable that the RCM element 13 an at least partially independent evaluation, which in a housing of the RCM element 13 is arranged.

On the evaluation unit 12 At least two limit values are stored. For this purpose, the evaluation unit 12 a not-shown storage unit. The evaluation unit 12 is intended to be the output value of the sensor unit 11 with those on the evaluation unit 12 to compare stored limit values. The evaluation unit 12 is intended to trigger a warning mode when the output value of the sensor unit 11 exceeds the first limit. As soon as the output value of the sensor unit 11 exceeds the second limit is the evaluation 12 intended to trigger a shutdown mode: The limit value for the warning mode is 2 mA, preferably 3 mA and in a particularly advantageous embodiment, 5 mA. The limit value for the shutdown mode is 10 mA, preferably 20 mA and in a particularly advantageous embodiment 30 mA.

The control unit 14 is provided to execute the warning mode and the shutdown mode. The warning mode and the shutdown mode are on the control unit 14 deposited operating programs by the control unit 14 can be executed. In the warning mode is the control unit 14 intended to issue a warning signal to a driver / operator. In the shutdown mode is the control unit 14 provided a circuit in the high-voltage on-board electrical system 10 to interrupt.

In the warning mode, the control unit gives 14 a warning signal to a driver / operator. The warning signal can take the form of a warning light or a message on a display in the driver's area. The driver / operator is informed by the warning signal that in the high-voltage vehicle electrical system 10 a low fault current has occurred and corresponding Measures, such as a review in a workshop, advised.

In the shutdown mode, the control unit interrupts 14 a circuit in the high-voltage vehicle electrical system 10 and thus interrupts a charging process of the battery device 15 , This opens the control unit 14 in the loading unit 16 arranged and not shown switching elements, the current flow in the high-voltage vehicle electrical system 10 interrupt. The switching elements are designed as contactors, the simple of the control unit 14 can be opened.

On the evaluation unit 12 is another first limit deposited. The further first limit value is formed as a slope of the fault current between at least two charging operations. The further first limit value lies with an increase of the fault current of 2%, preferably of 5% and particularly advantageously of 10% between at least 2 charging operations. The evaluation unit 12 stored for this purpose on the storage unit detected output values 12 the sensor unit 11 that are below the first threshold. Detects the evaluation unit 12 an increase in the output value of the sensor unit, which are above the further first limit value, triggers the evaluation unit via a number of multiple charging processes 12 also the warning mode off. The output values of the sensor unit 11 are below the first limit.

The evaluation unit 12 the evaluation of the output values of the sensor unit begins 11 as soon as the plug element of the external power supply system mechanically with the plug element 22 the loading unit 16 connected is. Once a stream through the charging unit 16 , and thus the sensor unit 11 , flows, gives the RCM element 13 the sensor unit 11 an output value to the evaluation unit 12 out. Exceeds the output value of the RCM element 13 the first limit value, triggers the evaluation unit 12 on the control unit 14 deposited warning mode. An increase in the limit value is caused by a fault current in the high-voltage vehicle electrical system 10 triggered. A fault current can occur in all components of the high-voltage vehicle electrical system 10 between the loading unit 16 and the battery device 15 , such as an air conditioner, an electric heater or other connected high-voltage consumers are detected. The connected high-voltage consumers do not have to be active. A fault current is also detected when the high-voltage consumers are inactive.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• WO 2006/058824 A2 [0002]

Claims (12)

Motor vehicle monitoring device for monitoring a high-voltage vehicle electrical system ( 10 ) during a charging process, with at least one sensor unit ( 11 ), which is intended to detect an occurring fault current in the high-voltage on-board electrical system ( 10 ) and output an output value, and with an evaluation unit ( 12 ), on which at least two limit values are stored and which is intended to trigger a warning mode when the output value is exceeded above the first limit value and to trigger a deactivation mode when the output value is exceeded above the second limit value. Motor vehicle monitoring device according to claim 1, characterized in that the output value of the sensor unit ( 11 ) is arranged to vary with a magnitude of a fault current. Motor vehicle monitoring device according to claim 1 or 2, characterized in that the sensor unit ( 11 ) an RCM element ( 13 ). Motor vehicle monitoring device according to one of the preceding claims, characterized in that the first limit value defines a low fault current. Motor vehicle monitoring device according to one of the preceding claims, characterized by a control and / or regulating unit ( 14 ) provided for executing the warning mode and the shutdown mode. Motor vehicle monitoring device according to claim 5, characterized in that the control and / or regulating unit ( 14 ) is intended to execute the warning mode when the evaluation unit ( 12 ) detects an exceeding of the output value above the first limit value and triggers the warning mode. Motor vehicle monitoring device according to claim 5 or 6, characterized in that the control and / or regulating unit ( 14 ) is provided in the warning mode to output a warning signal to a driver / operator. Motor vehicle monitoring device at least according to claim 5, characterized in that the control and / or regulating unit ( 14 ) is intended to execute the shutdown mode when the evaluation unit ( 12 ) detects an exceeding of the output value over the second limit value and triggers the warning mode. Motor vehicle monitoring device at least according to claim 5, characterized in that the control and / or regulating unit ( 14 ) is provided in the shutdown mode to a circuit in the high-voltage vehicle electrical system ( 10 ) to interrupt and thus to interrupt a charging process. Motor vehicle monitoring device according to one of the preceding claims, characterized by a further first limit value, which is formed as a slope of the fault current between at least two charging operations. Motor vehicle monitoring device according to one of the preceding claims, characterized in that the high-voltage vehicle electrical system 10 an inverter unit which is provided to convert an alternating current into a direct current during the charging process. Motor vehicle monitoring device according to one of the preceding claims, characterized by an electric motor 18 comprising at least one motor coil provided as an inductance in the charging process.

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