Motor Vehicle Electrical System Having An Active Bridge Rectifier And Overvoltage Protection During A Load Dump, Rectifier System, Associated Operating Method And Means For Its Implementation

• US 20140362625A1
• Filed: 05/15/2014
• Published: 12/11/2014
• Est. Priority Date: 05/15/2013
• Status: Active Grant

• Current Assignee: Seg Automotive Germany GMBH
• Original Assignee: Robert Bosch GmbH
• Inventors: MEHRINGER, Paul
• Granted Patent: US 9,641,097 B2
• Time in Patent Office: Days
• US Class Current: 363/127
• CPC Class Codes: H02H 7/1252 responsive to overvoltage in input or output, e.g. by load dump
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 7/2173 in a biphase or polyphase circuit arrangement H02M7/2176 takes precedence; voltage multipliers H02M7/25
• CPC Class Codes: H02M 7/219 in a bridge configuration
• CPC Class Codes: H02M 7/2195 the switches being synchronously commutated at the same frequency of the AC input voltage

Abstract

A vehicle electrical system includes: an active bridge rectifier which is connected to a generator via multiple phase terminals, and having terminals on the direct voltage side; a unit for recognizing load shedding at the active bridge rectifier and short-circuiting the phase terminals in a clocked manner, as the result of which a pulsed current is fed to the vehicle electrical system; a vehicle electrical system capacitor configured for smoothing the pulsed current; and a voltage limiting unit configured for clipping a voltage between the terminals of the bridge rectifier on the direct voltage side to a predefined maximum voltage.

Claims

1-15. -15. (canceled)

16. A vehicle electrical system, comprising:

an active bridge rectifier connected to a generator via multiple phase terminals, the active bridge rectifier having terminals on the direct voltage side;

a load shedding recognition unit which (i) recognizes load shedding at the active bridge rectifier, and (ii) when load shedding is recognized, short-circuits the phase terminals in a clocked manner to feed a pulsed current to the vehicle electrical system;

at least one vehicle electrical system capacitor which smoothes the pulsed current; and

a voltage limiter which clips a voltage between the terminals of the bridge rectifier on the direct voltage side to a predefined maximum voltage.

17. The vehicle electrical system as recited in claim 16, further comprising:

multiple active switching elements in a number of half bridges which correspond to the number of phase terminals, a first group of the active switching elements being controlled as a group in a clocked manner for the clocked short-circuiting of the phase terminals.

18. The vehicle electrical system as recited in claim 17, wherein the voltage limiter has at least one voltage-dependent element which establishes a conductive connection between the terminals of the bridge rectifier on the direct voltage side above the predefined maximum voltage.

19. The vehicle electrical system as recited in claim 18, wherein the at least one voltage-dependent element includes at least one of a Zener diode and a varistor having one of a breakdown voltage or a threshold voltage corresponding to the predefined maximum voltage.

20. The vehicle electrical system as recited in claim 18, wherein the at least one voltage-dependent element includes at least one controllable switching element which switches over from a nonconductive state into a conductive state above the predefined maximum voltage.

21. The vehicle electrical system as recited in claim 18, wherein the at least one voltage-dependent element is integrated between the terminals on the direct voltage side.

22. The vehicle electrical system as recited in claim 18, wherein multiple voltage-dependent elements are provided, each voltage-dependent element being integrated between one of the terminals of the bridge rectifier on the direct voltage side and a gate terminal for at least a portion of the active switching elements.

23. The vehicle electrical system as recited in claim 18, wherein the active switching elements are configured, at least in part, as voltage-dependent elements in the form of avalanche-resistant active switching elements.

24. The vehicle electrical system as recited in claim 17, wherein the voltage limiter clips the voltage between the terminals on the direct voltage side to the predefined maximum voltage by controlling at least one active switching element which is not part of the first group of active switching elements.

25. A method for operating a vehicle electrical system which includes (i) an active bridge rectifier connected to a generator via multiple phase terminals, the active bridge rectifier having terminals on the direct voltage side, (ii) a load shedding recognition unit, (iii) at least one vehicle electrical system capacitor, and (iv) a voltage limiter, the method comprising:

ascertaining, by the load shedding recognition unit, an occurrence of load shedding at the active bridge rectifier;

upon ascertaining an occurrence of load shedding at the active bridge rectifier, short-circuiting the phase terminals by the load shedding recognition unit in a clocked manner to feed a pulsed current to the vehicle electrical system;

smoothing, using the at least one vehicle electrical system capacitor, the pulsed current; and

clipping, using the voltage limiter, a voltage which is present between the terminals of the bridge rectifier on the direct voltage side to a predefined maximum voltage.

26. The method as recited in claim 25, wherein the voltage limiter has a voltage-dependent element which includes at least one controllable switching element, and wherein the voltage which is present between the terminals of the bridge rectifier on the direct voltage side is clipped to the predefined maximum voltage by controlling the at least one controllable switching element.

27. The method as recited in claim 25, wherein the vehicle electrical system has multiple active switching elements in a number of half bridges which correspond to the number of phase terminals, a first group of the active switching elements being controlled as a group in a clocked manner for the clocked short-circuiting of the phase terminals.

28. The method as recited in claim 27, wherein the voltage between the terminals on the direct voltage side is clipped to the predefined maximum voltage by controlling at least one active switching element which is not part of the first group of active switching elements.

29. A non-transitory computer-readable data storage medium storing a computer program having program codes which, when executed on a computer, performs a method for operating a vehicle electrical system which includes (i) an active bridge rectifier connected to a generator via multiple phase terminals, the active bridge rectifier having terminals on the direct voltage side, (ii) a load shedding recognition unit, (iii) at least one vehicle electrical system capacitor, and (iv) a voltage limiter, the method comprising:

ascertaining, by the load shedding recognition unit, an occurrence of load shedding at the active bridge rectifier;

upon ascertaining an occurrence of load shedding at the active bridge rectifier, short-circuiting the phase terminals by the load shedding recognition unit in a clocked manner to feed a pulsed current to the vehicle electrical system;

smoothing, using the at least one vehicle electrical system capacitor, the pulsed current; and

clipping, using the voltage limiter, a voltage which is present between the terminals of the bridge rectifier on the direct voltage side to a predefined maximum voltage.