Control device for a DC-to-DC converter of an electrical drive system, and a method for operating a DC-to-DC converter

• US 9,487,093 B2
• Filed: 08/02/2012
• Issued: 11/08/2016
• Est. Priority Date: 09/20/2011
• Status: Active Grant

• Current Assignee: Robert Bosch GmbH
• Original Assignee: Robert Bosch GmbH
• Inventors: Raichle, Daniel, Knorpp, Thomas, Ruffer, Michael, Michels, Markus
• Primary Examiner(s): Jackson, Stephen W
• Application Number:
  US14/345,768
• Publication Number:
  US 20140217817A1
• Time in Patent Office: 1,559 Days
• Field of Search: 307/10.1
• US Class Current: 1/1
• CPC Class Codes: B60L 1/003 to auxiliary motors, e.g. for pumps, compressors
• CPC Class Codes: B60L 1/006 to power outlets
• CPC Class Codes: B60L 1/08 Methods and devices for control or regulation
• CPC Class Codes: B60L 2210/10 DC to DC converters
• CPC Class Codes: B60L 2210/12 Buck converters
• CPC Class Codes: B60L 2210/40 DC to AC converters
• CPC Class Codes: B60L 2240/529 Current
• CPC Class Codes: B60L 2240/547 Voltage
• CPC Class Codes: B60L 2240/549 Current
• CPC Class Codes: B60L 2260/42 by adaptive correction
• CPC Class Codes: B60L 3/0046 relating to electric energy storage systems, e.g. batteries or capacitors
• CPC Class Codes: B60L 50/10 using propulsion power supplied by engine-driven generators, e.g. generators driven by combustion engines
• CPC Class Codes: B60L 50/16 with provision for separate direct mechanical propulsion
• CPC Class Codes: B60L 58/12 responding to state of charge [SoC]
• CPC Class Codes: B60L 58/15 Preventing overcharging
• CPC Class Codes: B60L 58/20 having different nominal voltages
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 10/72 Electric energy management in electromobility

Abstract

The invention relates to an electrical drive system of a hybrid vehicle, comprising: a traction battery (1), a high-voltage intermediate circuit (2), a pulse-controlled inverter (3) which is coupled to the high voltage intermediate circuit (2), an electrical machine (5) which is coupled to the pulse-controlled inverter (3); a DC-to-DC converter (6) which is coupled to the pulse-controlled inverter (3) and the high-voltage intermediate circuit (2) and is designed to convert a high voltage (UE) from the high-voltage intermediate circuit (2) into a low voltage (UA) for a vehicle electrical system; a low-voltage battery (8) which is coupled to the DC-to-DC converter (6); a plurality of selectively-connectable electrical consumers (9a, 9b) of the vehicle electrical system, which are coupled to the low-voltage battery (8) and the DC-to-DC converter (6); and a control device (7) which, in the event of a traction battery failure, is designed to operate the DC-to-DC converter (6) in a current-controlled manner using the electrical machine so as to supply said vehicle electrical system consumers (9a, 9b).

Claims

1. A control device (7) for actuating a DC-to-DC converter (6), comprising:

a voltage regulator (20), configured to regulate the output voltage (UA) of the DC-to-DC converter (6) as the control variable, and

a current regulator (30), configured to regulate the output current (IA) of the DC-to-DC converter (6) as the control variable,

wherein the control device (7) is designed to receive an operating mode selection signal (4a) and adjust the voltage regulator (20) as a function of the operating mode selection signal (4a) such that said voltage regulator (20) limits the output voltage (UA) of the DC-to-DC converter (6) to a predetermined constant maximum voltage (UM), and to adjust the current regulator (30) such that said current regulator (30) uses the difference between a predetermined nominal output voltage (US) and the output voltage (UA) of the DC-to-DC converter (6) as the control deviation.

2. The control device (7) according to claim 1, wherein the maximum voltage (UM) is greater than the nominal output voltage (US).

3. The control device (7) according to claim 1, wherein the operating mode selection signal (4a) indicates whether the input voltage (UE) of the DC-to-DC converter (6) is provided by an electrical machine (5) and wherein the control device (7) is designed to operate the DC-to-DC converter (6) in a current-controlled manner if the input voltage (UE) of said DC-to-DC converter (6) is provided by an electrical machine (5).

4. An electrical drive system (10) comprising:

a high-voltage intermediate circuit (2) which is fed by a high voltage source (1);

a pulse-controlled inverter (3) which is coupled to the high-voltage intermediate circuit (2);

an electrical machine (5) which is coupled to the pulse-controlled inverter (3);

a DC-to-DC converter (6) which is coupled to the pulse-controlled inverter (3) and the high-voltage intermediate circuit (2) and is designed to convert a high voltage (UE) from the high-voltage intermediate circuit (2) into a low voltage (UA) for a vehicle electrical system;

a low-voltage battery (8) which is coupled to the DC-to-DC converter (6);

a plurality of selectively-connectable electrical consumers (9a, 9b) of a vehicle electrical system, which are coupled to the low-voltage battery (8) and the DC-to-DC converter (6); and

a control device (7) according to claim 1 which is designed to actuate the DC-to-DC converter (6) in order to supply the low-voltage battery (8) and the plurality of vehicle electrical system consumers (9a, 9b) with a low voltage (UA) from the high voltage intermediate circuit (2).

5. The electrical drive system (10) according to claim 4, wherein the control device (7) is designed to adjust the current control equipment (3) such that the difference between a predetermined nominal output voltage (US) and the output voltage (UA) of the DC-to-DC converter (6) is used as the control deviation if the electrical machine (5) is operated in the generator mode and the high-voltage intermediate circuit (2) is fed by the pulse-controlled inverter (3) and the electrical machine (5).

6. The electrical drive system (10) according to claim 4 further comprising:

a power inverter control device (4) which is designed to actuate the pulse-controlled inverter (3) in a voltage control mode in order to supply the high-voltage intermediate circuit (5) by the electrical machine (5) in the event of a failure of the high voltage source (1).

7. The electrical drive system (10) according to claim 6, wherein the power inverter control device (4) is designed to output an operating mode selection signal (4a) to the control device (7), said signal indicating that said power inverter control device (4) is actuating the pulse-controlled inverter (3) in a voltage control mode.

8. A method (60) for operating a DC-to-DC converter (6), the method comprising:

determining (61) whether the input voltage (UE) of the DC-to-DC converter (6) is provided by an electrical machine (5) in a generator mode and

outputting a corresponding operating mode selection signal (4a);

operating (62) the DC-to-DC converter (6) in a current-controlled manner as a function of the operating mode selection signal (4a), wherein the operation of the DC-to-DC converter (6) comprises;

limiting (62a) the output voltage (UA) of the DC-to-DC converter (6) to a predetermined constant maximum voltage (UM); and

regulating (62b) the output current of the DC-to-DC converter (6) to a control deviation which is formed by the difference between a predetermined nominal output voltage (US) of the DC-to-DC converter (6) and the output voltage (UA) of said DC-to-DC converter (6).

9. The method (60) according to claim 8, wherein the maximum voltage (UM) is greater than the nominal output voltage (US).