DE102013207529A1 - Method for determining a current intensity of a current flowing into or out of a rechargeable battery connected to a power supply via at least one switch - Google Patents

Method for determining a current intensity of a current flowing into or out of a rechargeable battery connected to a power supply via at least one switch

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Publication number
DE102013207529A1
DE102013207529A1 DE102013207529.4A DE102013207529A DE102013207529A1 DE 102013207529 A1 DE102013207529 A1 DE 102013207529A1 DE 102013207529 A DE102013207529 A DE 102013207529A DE 102013207529 A1 DE102013207529 A1 DE 102013207529A1
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Germany
Prior art keywords
voltage
switch
frequency
current
test alternating
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
DE102013207529.4A
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German (de)
Inventor
Stefan Butzmann
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Robert Bosch GmbH
Samsung SDI Co Ltd
Original Assignee
Robert Bosch GmbH
Samsung SDI Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Publication date
Application filed by Robert Bosch GmbH, Samsung SDI Co Ltd filed Critical Robert Bosch GmbH
Priority to DE102013207529.4A priority Critical patent/DE102013207529A1/en
Publication of DE102013207529A1 publication Critical patent/DE102013207529A1/en
Pending legal-status Critical Current

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    • GPHYSICS
    • G01MEASURING; TESTING
    • G01RMEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R19/00Arrangements for measuring currents or voltages or for indicating presence or sign thereof
    • G01R19/0092Arrangements for measuring currents or voltages or for indicating presence or sign thereof measuring current only
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60LPROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L3/00Electric devices on electrically-propelled vehicles for safety purposes; Monitoring operating variables, e.g. speed, deceleration or energy consumption
    • B60L3/12Recording operating variables ; Monitoring of operating variables
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60LPROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00Control parameters of input or output; Target parameters
    • B60L2240/40Drive Train control parameters
    • B60L2240/54Drive Train control parameters related to batteries
    • B60L2240/547Voltage
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B60VEHICLES IN GENERAL
    • B60LPROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L2240/00Control parameters of input or output; Target parameters
    • B60L2240/40Drive Train control parameters
    • B60L2240/54Drive Train control parameters related to batteries
    • B60L2240/549Current

Abstract

The invention relates to a method for determining a current of a current flowing into or out of an accumulator, in particular a lithium-ion accumulator, connected to a power supply via at least one switch, in particular a contactor, characterized in that in the closed operating state of the current-carrying switch, the detected by the current across the switch falling base voltage and the contact resistance of the switch is determined, whereby to determine the contact resistance of the switch, the base voltage is superimposed with a test AC voltage, the frequency of which lies outside the frequency spectrum of the base voltage, and wherein the current intensity of the current flowing through the switch is determined from the ratio of the detected basic voltage and the determined contact resistance (RK) of the switch.

Description

  • State of the art
  • In electrically powered motor vehicles, in particular electric vehicles and hybrid electric vehicles, accumulators are used to provide them with electrical energy via a vehicle-side power grid electrical drive means of the motor vehicle. For this purpose, the accumulators are usually connected via contactors with the power grids. Depending on the switching state of the contactors, the accumulators can thus be connected to or disconnect from the power grid. As accumulators are usually used as lithium-ion batteries.
  • The current flowing into or out of such an accumulator must be used to determine the respective state of charge of the accumulator and from Sicherheitsbzw. Be monitored for diagnostic reasons. For this purpose, current sensors, such as shunt sensors or Hall sensors, used, which is relatively expensive because of the typically occurring currents of up to several hundred amps. In order to enable the most accurate possible determination of the respective current strength, it is also known to connect two current sensors in series, which are based on different measurement methods. The information generated by these current sensors can then be mutually plausible.
  • Disclosure of the invention
  • The invention relates to a method for determining a current strength of an in or out of at least one switch, in particular contactor, connected to a power supply accumulator, in particular lithium-ion accumulator, flowing stream, characterized in that in the closed operating state of the current-carrying switch detects the falling by the current across the switch base voltage and the contact resistance of the switch is determined, wherein the base voltage is superimposed with a test AC voltage whose frequency is outside the frequency spectrum of the fundamental voltage to determine the contact resistance of the switch, and wherein the current flowing through the switch Current is determined from the ratio of the detected base voltage and the determined contact resistance of the switch.
  • The current intensity of the current flowing through the switch corresponds to the current intensity of the current flowing into or out of the rechargeable battery. The determination according to the invention of the current intensity of the current flowing into or out of the rechargeable battery via the switch requires no additional and costly current sensors for detecting the current intensity of the current flowing into or out of the rechargeable battery.
  • Since the determination of the contact resistance of the switch and the detection of the falling across the switch base voltage in different non-overlapping spectral regions, the determination of the contact resistance and thus the determination of the current flowing through the switch during the closed operating state of the switch can be done, which a reliable and safe monitoring of the operating condition of the accumulator makes possible.
  • The current flowing through the switch may be a direct current or an alternating current.
  • According to an advantageous embodiment, the frequency of the test alternating voltage is above the frequency spectrum of the fundamental voltage. By superposing the basic voltage with such a test alternating voltage, the fundamental voltage is modulated. For example, the current may have a frequency of up to 10 kHz and the test alternating voltage may have a frequency of 100 kHz.
  • According to a further advantageous embodiment, the voltage drop across the switch, generated by the superposition of ground voltage and test AC voltage overlap voltage is detected by means of a first amplifier. For this purpose, the first amplifier is connected in parallel with the switch.
  • According to a further advantageous embodiment, the overlay voltage detected by the first amplifier is frequency-filtered by means of a first low-pass filter for detecting the base voltage, the first low-pass filter having a cutoff frequency below the frequency of the test alternating voltage. This is useful if the frequency of the test alternating voltage is above the frequency spectrum of the fundamental voltage. Due to the low-pass filtering of the superposition voltage, the signal component contained in the superposition voltage by the test alternating voltage is filtered out of the superposition voltage, so that after filtering the superposition voltage, the base voltage is present at the output of the low-pass filter and can be detected.
  • A further advantageous embodiment provides that the overlapping voltage generated across the switch and generated by the superimposition of the base voltage and the test alternating voltage is detected by means of a second amplifier. For this purpose, the second amplifier is to be connected in parallel to the switch.
  • According to a further advantageous refinement, the overlay voltage detected by the second amplifier is multiplied by the test alternating voltage by means of a multiplier to generate an intermediate voltage. The intermediate voltage can then be decomposed into a frequency-dependent and a frequency-independent part.
  • It is further considered advantageous if the intermediate voltage for the generation of a filtered voltage signal is frequency-filtered by means of a second low-pass filter having a lying below the frequency of the test alternating voltage cutoff frequency. As a result, the frequency-dependent part of the intermediate voltage can be filtered out so that the frequency-independent part alone is present at the output of the low-pass filter from the intermediate voltage.
  • According to a further advantageous refinement, the detected basic voltage and the filtered voltage signal are fed to an analog-to-digital converter and converted by the latter into a first voltage end signal assigned to the basic voltage and a second voltage end signal assigned to the filtered voltage signal. As a result, the basic voltage and the filtered voltage signal in the form of the first voltage end signal or of the second voltage end signal can be processed by an electronic evaluation device.
  • According to a further advantageous embodiment, the voltage end signals generated by the analog-to-digital converter are supplied to an electronic evaluation device which is set up to determine the contact resistance of the switch from the second voltage signal and to set the first voltage end signal in relation to the determined contact resistance of the switch. The electronic evaluation device may be an already existing part of a vehicle electronics or a device that can be arranged separately therefor.
  • The invention furthermore relates to a drive system for an electrically driven motor vehicle, in particular an electric vehicle or hybrid electric vehicle, comprising an accumulator, in particular a lithium-ion accumulator, a power network which can be connected to at least one electric drive device of the motor vehicle and an electronic device for monitoring the state of the drive system in which the accumulator is connected to the power supply via at least one switch, in particular a contactor, characterized in that the electronic device is designed to carry out the method according to one of the above embodiments or any combination thereof. This brings with it the advantages mentioned above. The electronic device may be an already existing part of a vehicle electronics or a device that can be arranged separately therefor.
  • According to an advantageous embodiment, the electronic device comprises: an alternating voltage source switchable in series with the switch, with which a test alternating voltage can be generated whose frequency lies outside the frequency spectrum of the fundamental voltage; a series connected to the AC voltage source electrical resistance; two amplifiers switchable in parallel with the switch; two low-pass filters, one of which is connected downstream of one of the amplifiers in series and whose respective cut-off frequency is below the frequency of the test alternating voltage; a multiplier connected in series with one of the amplifiers and connected to the AC source; and an electronic evaluation device connected to the outputs of the low passes. Such an embodiment of the electronic device is suitable for carrying out the method described above.
  • In the following, the invention will be explained by way of example with reference to the attached figures with reference to preferred exemplary embodiments, wherein the features illustrated below may represent an aspect of the invention both individually and in various combinations with one another. Show it
  • 1 : An exemplary circuit diagram of a switch connected to an electronic device of the drive system according to the invention and
  • 2 : an exemplary presentation of further details of in 1 shown electronic device.
  • 1 shows an embodiment of the electronic device 1 the drive system according to the invention 2 for a not shown, electrically powered motor vehicle. The drive system 2 comprises a rechargeable battery, not shown, in the form of a lithium-ion battery and a connectable to at least one electric drive device of the motor vehicle, not shown power network. The accumulator is connected via a designed as a contactor switch to the mains, wherein the switch is shown in the form of its contact resistance R K. In the illustrated closed operating state of the switch, this is traversed by a current flowing in or out of the accumulator current, whereby a base voltage drops at the switch.
  • The electronic device 1 includes an AC voltage source connected in series with the switch 3 , with a test alternating voltage u (t) = U 0 · sin (ω · t) can be generated, the frequency is above the frequency spectrum of the falling voltage at the switch base voltage. One connection of the AC voltage source 3 is with one terminal of the switch and the other terminal of the AC source 3 is one in series with the AC source 3 connected electrical resistor R P connected to the other terminal of the switch. If the contact resistance R K of the switch is chosen to be much smaller than the series resistor R P (R K << R P ), then the current strength of the current flowing through the switch is generated by the test alternating voltage u (t)
    Figure DE102013207529A1_0002
  • The electronic device 1 further comprises two amplifiers connected in parallel with the switch 4 and 5 on, by means of which in each case the falling over the switch, generated by the superposition of base voltage and test alternating voltage u (t) overlapping voltage is detected. From the amplifiers 4 and 5 in each case the AC voltage dropping across the switch by the test alternating voltage u (t)
    Figure DE102013207529A1_0003
    measured.
  • To detect the falling of the switch base voltage is that of the first amplifier 4 detected overlay voltage by means of a first low-pass filter 6 frequency filtered, with the first low pass 6 has a below the frequency of the test alternating voltage u (t) lying limit frequency. The basic voltage can be at the connection point 7 tapped and one in 2 shown analog-to-digital converter 10 supplied and converted by this to a first voltage end signal, which an electronic evaluation device 11 can be supplied in the form of a microcontroller.
  • The electronic device 1 further includes a second amplifier 5 connected in series, with the AC voltage source 3 connected multipliers 8th on. With the multiplier 8th is the across the switch through the test alternating voltage u (t) falling AC voltage u K (t) with that of the AC voltage source 3 generated test alternating voltage u (t) multiplied. For the following from this multiplication intermediate voltage u M (t) follows
    Figure DE102013207529A1_0004
    where a is the gain of the amplifier 5 designated. This equation can be transformed into
    Figure DE102013207529A1_0005
  • The amplifier 5 is a second low pass 9 connected in series whose cutoff frequency is below the frequency of the test alternating voltage u (t). After filtering the intermediate voltage u M (t) by means of the low-pass filter 9 lies at the exit of the low pass 9 a frequency-filtered and time-independent voltage signal
    Figure DE102013207529A1_0006
    in front. Since the values for R P , a and U 0 are constant and known, the relation U out ~ R K arises. The filtered voltage signal U out can be at the connection point 12 tapped and accordingly 2 an analog-to-digital converter 10 supplied and converted by this to a second voltage end signal, which an electronic evaluation device 11 can be supplied in the form of a microcontroller. To determine the contact resistance R K of the switch, the values for R P , a and U 0 in the electronic evaluation device 11 deposited or retrievable from this by another storage medium, not shown. This is the electronic evaluation device 11 arranged to determine from the second voltage end signal, the contact resistance R K of the switch and to set the first voltage end signal in relation to the determined contact resistance R K of the switch.

Claims (11)

  1. A method for determining a current strength of an in or from at least one switch, in particular contactor, connected to a power supply accumulator, in particular lithium-ion accumulator, flowing stream, characterized in that in the closed operating state of the current-carrying switch through the current through detects the base voltage dropping the switch and the contact resistance (R K ) of the switch is determined, wherein for determining the contact resistance (R K ) of the switch, the base voltage with a test alternating voltage ( u (t)) is superimposed whose frequency is outside the frequency spectrum of the fundamental voltage, and wherein the current intensity of the current flowing through the switch of the ratio of the detected fundamental voltage and the determined contact resistance (R K ) of the switch is determined.
  2. A method according to claim 1, characterized in that the frequency of the test alternating voltage (u (t)) is above the frequency spectrum of the fundamental voltage.
  3. Method according to Claim 2, characterized in that the superposition voltage generated across the switch and generated by the superimposition of fundamental voltage and test alternating voltage (u (t)) is determined by means of a first amplifier ( 4 ) is detected.
  4. A method according to claim 3, characterized in that for detecting the ground voltage from the first amplifier ( 4 ) detected overlay voltage by means of a first low pass ( 6 ) is frequency filtered, the first low pass ( 6 ) has a cutoff frequency below the frequency of the test alternating voltage (u (t)).
  5. Method according to one of the preceding claims, characterized in that the superimposed voltage which is dropped across the switch and generated by the superimposition of fundamental voltage and test alternating voltage (u (t)) by means of a second amplifier ( 5 ) is detected.
  6. Method according to claim 5, characterized in that that of the second amplifier ( 5 ) detected superposition voltage for generating an intermediate voltage (u M (t)) by means of a multiplier ( 8th ) is multiplied by the test alternating voltage (u (t)).
  7. A method according to claim 6, characterized in that the intermediate voltage (u M (t)) for generating a filtered voltage signal (U out ) by means of a second low pass ( 9 ) is frequency-filtered, having a below the frequency of the test alternating voltage (u (t)) lying limit frequency.
  8. A method according to claim 7, characterized in that the detected fundamental voltage and the filtered voltage signal (U out ) an analog-to-digital converter ( 10 ) are supplied and converted by the latter for generating a first voltage end signal assigned to the base voltage and a second voltage end signal assigned to the filtered voltage signal (U out ).
  9. A method according to claim 8, characterized in that the from the analog-to-digital converter ( 10 ) generated voltage end signals of an electronic evaluation device ( 11 ), which is configured to determine from the second voltage signal (U out ) the contact resistance (R K ) of the switch and to set the first voltage end signal in relation to the determined contact resistance (R K ) of the switch.
  10. Drive system ( 2 ) for an electrically driven motor vehicle, in particular an electric vehicle or hybrid electric vehicle, comprising an accumulator, in particular a lithium-ion accumulator, a power network connectable to at least one electric drive device of the motor vehicle and an electronic device ( 1 ) for monitoring the state of the drive system ( 2 ), wherein the accumulator is connected via at least one switch, in particular contactor, to the power network, characterized in that the electronic device ( 1 ) is arranged to carry out the method according to one of the preceding claims.
  11. Drive system ( 2 ) according to claim 11, characterized in that the electronic device ( 1 ) comprises: an alternating voltage source switchable in series with the switch ( 3 ), with which a test alternating voltage (u (t)) can be generated whose frequency lies outside the frequency spectrum of the fundamental voltage; one in series with the AC source ( 3 ) switched electrical resistance (R P ); two amplifiers switchable in parallel with the switch ( 4 . 5 ); two low passes ( 6 . 9 ), one of each of which is an amplifier ( 4 . 5 ) is connected in series and whose respective cutoff frequency is below the frequency of the test alternating voltage (u (t)); one of the amplifiers ( 5 ) connected in series, with the AC voltage source ( 3 ) connected multipliers ( 8th ); and one with the outputs of the low passes ( 6 . 9 ) connected electronic evaluation device ( 11 ).
DE102013207529.4A 2013-04-25 2013-04-25 Method for determining a current intensity of a current flowing into or out of a rechargeable battery connected to a power supply via at least one switch Pending DE102013207529A1 (en)

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DE102013207529.4A DE102013207529A1 (en) 2013-04-25 2013-04-25 Method for determining a current intensity of a current flowing into or out of a rechargeable battery connected to a power supply via at least one switch

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6522123B2 (en) * 1999-12-09 2003-02-18 Sagem Sa Apparatus for measuring current flowing in a conductor
US20030076086A1 (en) * 2000-12-25 2003-04-24 Isoshi Takeda Electrical quantity sensor
DE102009046564A1 (en) * 2009-11-10 2011-05-12 SB LiMotive Company Ltd., Suwon Battery control unit architecture
DE102012006269A1 (en) * 2011-03-29 2012-10-04 Continental Teves Ag & Co. Ohg Current sensor

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6522123B2 (en) * 1999-12-09 2003-02-18 Sagem Sa Apparatus for measuring current flowing in a conductor
US20030076086A1 (en) * 2000-12-25 2003-04-24 Isoshi Takeda Electrical quantity sensor
DE102009046564A1 (en) * 2009-11-10 2011-05-12 SB LiMotive Company Ltd., Suwon Battery control unit architecture
DE102012006269A1 (en) * 2011-03-29 2012-10-04 Continental Teves Ag & Co. Ohg Current sensor

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