DE102017113533A1 - Method and apparatus for compensating for mass offset in a high voltage vehicle system - Google Patents

Abstract

A method and apparatus for compensating a mass offset in a high voltage vehicle system, wherein in the high voltage vehicle system at least one compensation resistor (302, 302-1, ..., 302-n, 502) is disposed in parallel with a first isolation resistor (136) of the high voltage vehicle system, the first isolation resistor (136) connects a first high voltage contact (122) of the high voltage vehicle system to vehicle ground (126), wherein in the method, an effective isolation value of the high voltage vehicle system is adjusted, the effective isolation value being adjusted depending on an instantaneous voltage established between the first high voltage contact (122) and vehicle ground (126) falling between a second high voltage contact (124) of the high voltage vehicle system and the vehicle ground (126) and / or falling between the first high voltage contact (122) and the second high voltage contact (124).

Description

The invention relates to a method and a device for compensating a mass offset, in particular in a high voltage vehicle system.

In vehicles with high-voltage vehicle systems, two high-voltage contacts are provided for electrically charging a battery of the vehicle for connecting the vehicle to two corresponding contacts of a charging station via a charging cable.

For monitoring the high-voltage vehicle system during the charging process, an insulation monitoring circuit is integrated in the charging stations. The isolation monitoring circuit is used to measure an insulation resistance between the two potentials of the two contacts in a high voltage vehicle system. If the insulation value is too low, an action, for example a shutdown of the high-voltage vehicle or of the charging system, is carried out.

The DE 102 010 006 108 . FR 3026191 . US 2008 158 756 . US 2016 096 433 and US 2016 214 484 disclose such insulation monitoring circuits for measuring an insulation resistance between individual potentials in a vehicle electrical system of a motor vehicle. In case of DE 102 010 006 108 . US 2008 158 756 . US 2016 096 433 and US 2016 214 484 In addition, the isolation monitor circuit identifies whether system resistances are symmetric or not. In addition, insulation faults are also detected.

These isolation monitoring circuits assume that in an error-free state, an insulation value between the individual potentials is the same. This means that the contact of the high voltage positive pole has the same potential with respect to ground, which also has the contact of the high voltage negative pole with respect to ground.

A deviation of this symmetry leads in the known insulation monitoring circuits to a detection of an insulation fault. This also provides a faultless system, i. a system that has an asymmetric ground offset of the potentials of the two contacts with respect to the ground is turned off by the isolation monitoring circuit.

It is therefore desirable to provide an improved high voltage vehicle system on the other hand.

This is achieved by the method and apparatus of the independent claims.

With regard to the device, it is provided to arrange at least one compensation resistor in parallel connection to an insulation resistance of the high voltage vehicle system in the high voltage vehicle system, wherein the insulation resistance connects a high voltage contact of the high voltage vehicle system with vehicle ground.

By the parallel connection of the compensation resistor to the insulation resistance of the system to be monitored, an effective insulation resistance of the complete high-voltage vehicle system is changed in the event of a mass offset. The effective insulation resistance is the measurable by a charging station resistance. By correct dimensioning of the compensation resistor, its influence on the effective insulation resistance detected by the insulation monitoring circuit compensates for the influence of the ground offset. The insulation monitoring circuit, or a measuring circuit in the insulation monitoring circuit, thus recognizes a symmetrical system. In the event of an insulation fault occurring in the high-voltage vehicle system, the ability is still maintained that the insulation monitoring circuit recognizes it and switches off the high-voltage vehicle system with an insulation fault. For this purpose, the compensation resistor is dimensioned depending on known system boundary conditions, for example a charging voltage or a resistance value of measuring resistors of the measuring circuit such that the measuring circuit detects a symmetrical system when the high-voltage vehicle is connected to the charging station via the charging cable.

• 1 schematisch Teile eines unverbundenen Fahrzeugladesystems,
• 2 Teile eines verbundenen Fahrzeugladesystems,
• 3 schematisch Teile eines verbundenen Fahrzeugladesystems mit Kompensationswiderstand,
• 4 schematisch Teile eines verbundenen Fahrzeugladesystems mit mehreren Kompensationswiderständen,
• 5 schematisch Teile eines verbundenen Fahrzeugladesystems mit mehreren Kompensationswiderständen und einem variablen Kompensationswiderstand.

Further advantageous embodiments of the invention will become apparent from the following description and the drawings. In the drawing shows:

• 1 schematically parts of an unconnected vehicle charging system,
• 2 Parts of a connected vehicle charging system,
• 3 schematically parts of a connected vehicle charging system with compensation resistor,
• 4 schematically parts of a connected vehicle charging system with several compensation resistors,
• 5 schematically parts of a connected vehicle charging system with multiple compensation resistors and a variable compensation resistor.

The 1 schematically shows parts of a vehicle charging system 100 in which a charging station 102 and a vehicle 104 unconnected.

The charging station 102 is with a power supply of, for example, 400 volts between a first high voltage contact 106 and a second high voltage contact 108 connected. The first high voltage contact 106 is in the example compared to mass on positive potential. The second high voltage contact 108 is in the example compared to mass at a negative potential.

The charging station 102 has a charging station interface 110 on. In the charging station interface 110 is a first charging point contact 112 arranged with the first high-voltage contact 106 is electrically connected. In the charging station interface 110 is a second charging point contact 114 arranged with the second high-voltage contact 108 is electrically connected. In addition, in the charging station interface 110 a charging pole ground contact 116 arranged. The charging pole ground contact 116 is grounded in the example.

Between the charging pole ground contact 116 and the first charging point contact 112 is a first measuring resistor 118 arranged. Between the charging pole ground contact 116 and the second charging post contact 114 is a second measuring resistor 120 arranged.

The first measuring resistor 118 and the second measuring resistor 120 are dimensioned so that the voltage across the first measuring resistor 118 drops and the voltage across the second measuring resistor 120 falls down to be divided symmetrically. At the charging station, for example, there are 400 volts, which are divided symmetrically on each 200V across each of the resistors. In the example fall over the charging column ground contact 116 and the first charging point contact 112 thus 200 volts. In the example fall between the charging column ground contact 116 and the second charging post contact 114 also 200 volts. The first measuring resistor 118 and the second measuring resistor 120 preferably have the same resistance values.

One in the vehicle 104 arranged high voltage vehicle system is via a first vehicle contact 122 and a second vehicle contact 124 with the charging station 102 connectable to charge a battery of the vehicle. This is an electrical connection between the first vehicle contact 122 and the first charging point contact 112 and an electrically conductive connection between the second vehicle contact 124 and the second charging post contact 114 produced. In addition, there is a connection between the charging column mass contact 116 and vehicle mass 126 produced.

The first vehicle contact 122 is having a first contact 128 electrically connected to the high voltage vehicle system. The second vehicle contact 124 is via a DCDC converter 130 with a second contact 132 connected to the high voltage vehicle system. The DCDC converter is configured to have a potential of a voltage at the second vehicle contact 124 increase in value.

This is one between the first contact 128 and the second contact 132 decreasing voltage greater than a voltage between the first vehicle contact 122 and the second vehicle contact 124 ,

Between the vehicle mass 126 and a first electrical conductor 134 that the first vehicle contact 122 and the first contact 128 electrically conductive connects, is a first insulation resistance 136 arranged. Between the vehicle mass 126 and a second electrical conductor 138 that the second contact 132 with an exit 140 of the DCDC converter is a second insulation resistance 142 arranged. The term insulation resistance here refers to an equivalent resistance value, which serves to illustrate the actual insulation resistance.

The high voltage vehicle system is formed, for example, between the first contact 128 and the second contact 132 to provide a voltage of 800 volts. The insulation resistors are dimensioned so that in error-free case, and without mass offset between the vehicle mass 126 and the first contact 128 half the voltage drops between the first contact 128 and the second contact 132 is offered. Accordingly, the voltage between the second contact 132 and the vehicle mass just as big. In the example, the voltage amounts to 400 volts between the first contact 128 and vehicle mass and between the second contact 132 and vehicle mass when the vehicle 104 via the charging cable with the charging station 102 is connected.

2 FIG. 12 schematically illustrates a connected vehicle charging system. The reference numerals that functionally describe the same parts of the vehicle charging system that were previously described are in FIG 2 denoted by the same reference numeral as in FIG 1 , These items will not be explained again.

When the charging cable is plugged in, the charging station is 102 with the vehicle 104 via the charging station interface 110 connected. Especially is the first charging point contact 112 with the first vehicle contact 122 electrically connected. In particular, the second charging column contact 114 with the second vehicle contact 124 electrically connected. In addition, the charging column ground contact 160 via a ground line 202 with vehicle mass 126 connected.

Ladesäulenseitig is again provided in the example, a power supply with 400 volts, via the first measuring resistor 118 and the second measuring resistor 120 fall off.

On the vehicle side, the high voltage vehicle system in the example between the first contact 128 and the second contact 132 800 volts ready again.

Due to a mass offset, which may be caused for example by an asymmetry in the circuit of the high voltage vehicle system fall in the example, however, between the first contact 128 and ground of the 800 volts only 250 volts. The actual insulation values remain the same size. This drops between the second contact 132 and vehicle mass 126 the remaining voltage, ie 650 volts, from. Due to the parallel connection of insulation values of the vehicle with measuring resistors of the charging station, this offset results. Some charging stations then interpret this as an insulation fault, since it is not the resistance that is measured directly, but, for example, the voltage (as in this example) or the current on a ground line.

This asymmetry affects the voltage distribution in the charging station 102 such that over the first measuring resistor 118 already drop 250 volts. Then fall over the second measuring resistor 120 from the 400 volts the remaining 150 volts.

The charging station 102 recognizes thereby an asymmetry, which is detected as isolation error. This deactivates the high voltage vehicle system in conventional vehicle charging systems.

3 in contrast, provides the improved vehicle charging system 300 dar. Previously described elements with comparable function are in 3 denoted by the same reference numerals as in the description of 1 and 2 , These will not be explained further.

3 represents the vehicle charging system in the state in which the charging cable is plugged.

In addition to the measuring resistors and the insulation resistances in the vehicle is a first compensation resistor 302 in parallel with the first insulation resistance 136 arranged. In addition, a switch 304 between the first compensation resistor 302 and the first electrical conductor 134 be arranged, through which the parallel connection of the first compensation resistor 302 with the first insulation resistance 136 is switched in parallel or the parallel connection is interrupted. In the example the power supply is at the charging station 102 as previously described 400 volts. As a result, lie between the first contact and the second contact 132 800 volts as previously described. If the parallel connection of the first compensation resistor 302 is connected, ie with the switch closed 304 , falls over the parallel circuit of the first compensation resistor and the first insulation resistance 136 one opposite the in 2 shown conventional circuit different voltage value. The voltage value is thus dependent on the first compensation resistor 302 changed. In the example, the first combination resistance becomes 302 dimensioned such that above the first measuring resistor 118 in the example 200 volts, ie half of the 400 volt power supply drop. This also causes the second measuring resistor to fall 200 Volt off. The charging station 102 , or the measuring circuit in the charging station 102 , thus recognizes a symmetrical voltage distribution over the first measuring resistor 118 and the second measuring resistor 120 although the voltage distribution is above the first insulation resistance 136 and the second insulation resistance 142 would be asymmetrical. In the example, the voltage distribution there is 200 volts above the first insulation resistance and 600 volts above the second insulation resistance 142 ,

The first compensation resistor 302 depends on the knowledge of the charging station 102 , in particular the measuring resistors 118 and 120 as well as knowledge about the high voltage vehicle system dimensioned. As a result, a simple robust vehicle charging system can be realized, which can compensate static asymmetries by static mass offset in the high voltage vehicle system.

4 shows a contrast, further improved vehicle charging system, in which several compensation resistors 302-1 to 302-n in parallel with each other and the first insulation resistance 136 can be arranged. In particular, there are several switches 304-1 to 304-n provided by each of the individual compensation resistors 302-1 to 302-n individually, ie individually, optionally in parallel with the first insulation resistance 136 is operable or not. This is an effective insulation resistance, ie by the charging station 102 ie the measuring circuit in the charging station 102 , recognizable effective insulation resistance of the high-voltage vehicle system changeable adjustable.

Are different measuring circuits in different charging stations in use, can thus by selective connection or disconnection of individual compensation resistors 302-1 to 302-n an adjusted to the particular measuring circuit used effective insulation resistance can be adjusted. These are individual compensation resistors 302-1 to 302-n depending on system boundary conditions and known measuring circuits, in particular known measuring resistors dimensioned so that for on-market charging stations 102 at least one combination of compensation resistors 302-1 to 302-n can produce an effective insulation resistance, which avoids an error detection of an insulation fault by the respective measuring circuit.

In the in 4 For example, the same reference numbers are used for the remaining elements that correspond to the vehicle charging system of the example of FIG 3 correspond, provided with the same reference numeral.

Advantageously, by a communication between the vehicle 104 and the charging station 102 , in particular in the context of the charging process, information about the charging column type exchanged. In this case, the switches are provided 304-1 to 304-n optionally to close or disconnect depending on a detected charging column type. Preferably, this is a table in a control unit of the vehicle 104 provided, in each known charging column type a specific position of the switch 304-1 to 304-n assigned. The switches 304-1 to 304-n are closed or separated by the control unit by means of appropriate signals.

5 on the other hand represents a further improved vehicle charging system, in addition to the first compensation resistor 302 or in addition to the compensation resistors 302-1 to 302-n at least one variable compensation resistor 502 in series with at least one of these compensation resistors 302-1 to 302-n is arranged. In principle, a variable compensation resistor can also be used 502 be arranged alone. The remaining elements of the example 5 correspond to those previously in the examples too 2 respectively. 3 described elements and are denoted by the same reference numerals as there. Due to the variable compensation resistor 502 is the voltage between the first vehicle contact 122 and mass 126 and the voltage between the second vehicle contact 124 and mass 126 variably adjustable.

If a measuring circuit is not known, it is determined by the adjustable variable compensation resistor 502 a mass offset in a range compensated, which is expected from the current standardized charging systems. In particular, this excludes a range of small effective insulation values in which safety requirements for the charging system are no longer met. Preferably, this is between the first vehicle contact 122 and ground a first voltmeter 504 arranged. Preferably, this is between the second vehicle contact 124 and mass 126 a second voltmeter 506 arranged. These are via signal lines to the control unit of the vehicle 104 connected to the switches 304 . 304-1 to 304-n on. In this case, for example, a dynamic compensation of the mass offset, by the adjustable variable compensation resistor 502 is controlled so that the mass offset is compensated, ie the two voltage values on the first voltmeter 504 and at the second voltmeter 506 have the same value in terms of amount. There may be a predefinable tolerance for deviations from the measuring circuits in charging stations 102 be tolerated, be provided.

This sees an insulation monitoring circuit, ie the measuring circuit in the charging station 102 , in any case in the stationary state, ie when the adjustable variable compensation resistor 502 is set correctly, a symmetrical system.

By limiting the values that the adjustable variable compensation resistor 502 can assume an influence range can be limited by this compensation to set the minimum permissible insulation resistance in the system. Due to the variable proportion of the adjustable variable compensation resistor 502 in addition to an already connected compensation resistor 304 . 304-1 to 304-n is set, thus the effective insulation value can be influenced by compensation of the voltage. This is done for example by software that in the control unit of the vehicle 104 runs and contains instructions to know about their own high-voltage vehicle system and / or knowledge of the combination of compensation resistors 302 . 302-1 to 302-n a suitable value for the adjustable compensation resistor 502 adjust.

By the parallel connection of the compensation resistors 302 . 302-1 to 302-n and the adjustable variable compensation resistor 502 a real isolation resistance of the system may be reduced. To ensure that when controlling the adjustable compensation resistor 502 the high voltage vehicle system does not fall below a minimum real insulation resistance, preferably the value of the adjustable variable compensation resistance 502 dynamically depending on the real one Insulation resistance of the high voltage vehicle system limited. For this purpose, the real insulation resistance of the high-voltage vehicle, for example, independent of the external insulation monitoring circuit in the charging station 102 measured and stored. This occurs, for example, at vehicle start or during operation of the vehicle periodically. With knowledge of the own real insulation resistance value, preferably a value of the adjustable variable compensation resistance 502 limited for the period in which the external insulation monitoring circuit from a connected charging station 102 is active.

It is preferable to be aware of all resistance values in the parallel connection of the compensation resistors 302 . 302-1 to 302-n and optionally the adjustable variable compensation resistor 502 and the first insulation resistance 136 a resistance of the external insulation monitoring circuit in the charging station 102 , ie the first measuring resistor 118 , measured when the charging cable is connected. This is determined by the control unit in the vehicle 104 before the charging cable is connected, its own real insulation resistance and the values of the compensation resistors 302 . 302-1 to 302-n and variable compensation resistance 502 , These are adjusted so that a voltage between the first vehicle contact 122 and mass 126 as well as the second vehicle contact 124 and mass 126 is symmetrical. This means that the voltages are identical in terms of amount. Subsequently, for the insulation monitoring circuit of the charging station 102 If the charging cable is connected, a replacement resistor is determined. This becomes the charging station 102 assigned in the control unit in the vehicle 104 stored. This value can also be found in the charging station 102 stored in a corresponding memory and made available to other vehicles. By knowing the equivalent resistance of the charging station 102 For example, other comparable circuit vehicles may have a starting value for the adjustable variable compensation resistor control 502 set if your charging cable to the same charging station 102 is connected and if this value is transmitted to the control unit in this vehicle. Will be the same charging station 102 from the same vehicle 104 can also be used again, the control unit in the vehicle 104 this value for the regulation of the variable compensation resistance 502 underlie.

For example, monitors the high-voltage battery or a control unit for the high-voltage battery of the vehicle 104 the insulation resistance of the vehicle and sends a momentary value to the control unit that the compensation resistors 302 . 302-1 to 302-n and the variable compensation resistor 502 if necessary via the switches 304 . 304-1 to 304-n connects or disconnects in parallel.

Preferably, the compensation resistors are activated only when the control unit in the vehicle 104 recognizes that the charging station 102 used a measuring circuit, which requires a symmetrical wiring system.

The example uses an electrical system with 800 volts, which is charged via a charging station with 400 volts. The same procedure can also be used for all other voltages of both the charging column supply voltage or the high voltage vehicle system with appropriate dimensioning of the compensation resistors.

In the example is by the vehicle 104 , in particular by the DCDC converter, a voltage adjustment required because the electrical system of 800 volts is to be loaded with a charging station of 400 volts. This shifts the reference point for the high-voltage lines, the voltages are different. Basically, the system can also be used for other voltage conditions.

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

• DE 102010006108 [0004]
• FR 3026191 [0004]
• US 2008158756 [0004]
• US 2016096433 [0004]
• US 2016214484 [0004]

Claims (12)

Device for compensating a mass offset in a high voltage vehicle system, characterized in that in the high voltage vehicle system at least one compensation resistor (302, 302-1, ..., 302-n, 502) is arranged in parallel to a first insulation resistor (136) of the high voltage vehicle system, wherein the first isolation resistor (136) connects a first high voltage contact (122) of the high voltage vehicle system to vehicle ground (126). Device after Claim 1 characterized in that a second isolation resistor (142) connects a second high voltage contact (124) of the high voltage vehicle system to vehicle ground (126), and wherein the compensation resistor (302, 302-1, ..., 302-n, 502) is sized in that an effective insulation resistance of the high-voltage vehicle system formed by the first insulation resistance (136) and the compensation resistor (302, 302-1, ..., 302-n, 502) decreases in magnitude the same voltage as between the second high-voltage contact (124) and the vehicle mass (126). Device after Claim 1 or 2 , characterized in that optionally a plurality of compensation resistors (302-1, ..., 302-n) can be arranged in parallel to one another and to the first insulation resistance (136). Device according to one of Claims 1 to 3 characterized in that at least one adjustable variable compensation resistor (502) is disposed in parallel with the first isolation resistor (136). Device after Claim 4 , characterized in that the at least one adjustable variable compensation resistor (502) is arranged in series with at least one other compensation resistor (302, 302-1, ..., 302-n). Device after Claim 4 or 5 , characterized in that a resistance value that the at least one adjustable variable compensation resistor (502) can assume is greater than a minimum resistance value. Device according to one of Claims 1 to 6 characterized in that a plurality of compensation resistors (302, 302-1, ..., 302-n, 502) are provided, connected in series to each of the compensation resistors (302, 302-1, ..., 302-n , 502) a switch (304-1, ..., 304-n) is provided, by which each one of the compensation resistors (302-1, ..., 302-n) individually, optionally in parallel with the first insulation resistor (136 ) is operable or not. Device according to one of Claims 2 to 7 characterized by a controller adapted to set the effective isolation value. Device after Claim 8 characterized in that the controller is configured to adjust the effective isolation value in response to a current voltage dropping between the first high voltage contact (122) and the vehicle ground (126) connected between the second high voltage contact (124) and the vehicle ground (126). drops, and / or drops between the first high voltage contact (122) and the vehicle ground (126) to the second high voltage contact (124). Device according to one of Claims 8 or 9 characterized in that the controller is adapted to provide a value for the adjustable compensation resistor (502) in response to knowledge of a current combination of the compensation resistors (302-1, ..., 302-n) or a current position of the switches (304- 1, ..., 304-n). A method for compensating a ground offset in a high voltage vehicle system wherein in the high voltage vehicle system at least one compensation resistor (302, 302-1, ..., 302-n, 502) is arranged in parallel with a first insulation resistor (136) of the high voltage vehicle system, the first insulation resistance ( 136) connects a first high voltage contact (122) of the high voltage vehicle system to vehicle ground (126), characterized in that an effective isolation value of the high voltage vehicle system is set, wherein the effective isolation value is set depending on a current voltage that is between the first high voltage contact (122). and the vehicle ground (126) falling between a second high voltage contact (124) of the high voltage vehicle system and the vehicle ground (126) and / or falling between the first high voltage contact (122) and the second high voltage contact (124). Method according to Claim 11 characterized in that a value for an adjustable compensation resistor (502) is dependent upon knowledge of a current combination of compensation resistors (302-1, ..., 302-n) or a current position of switches (304-1, ... , 304-n), wherein each of the compensation resistors (302-1, ..., 302-n), optionally in., Is selected by the switches (304-1, ..., 304-n) Parallel connection to the first insulation resistor (136) is operable or not.

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