Startup sequence control method of fuel cell-super capacitor hybrid electric vehicle

• US 20090112384A1
• Filed: 12/31/2007
• Published: 04/30/2009
• Est. Priority Date: 10/26/2007
• Status: Active Grant

• Current Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Original Assignee: Hyundai Motor Company (Hyundai Motor Group)
• Inventors: Kwon, Sang Uk, Lee, Joon Yong, Jeon, Soon Il, Kang, Ho Sung
• Granted Patent: US 8,121,748 B2
• Time in Patent Office: Days
• US Class Current: 701/22
• CPC Class Codes: B60L 2240/545 Temperature
• CPC Class Codes: B60L 58/31 for starting of fuel cells
• CPC Class Codes: H01M 16/003 of fuel cells with other electrochemical devices, e.g. capacitors, electrolysers
• CPC Class Codes: H01M 8/04225 during start-up
• CPC Class Codes: H01M 8/04302 applied during start-up
• CPC Class Codes: H01M 8/04559 of fuel cell stacks
• CPC Class Codes: H01M 8/04567 of auxiliary devices, e.g. batteries, capacitors
• CPC Class Codes: H01M 8/04955 Shut-off or shut-down of fuel cells
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: Y02E 60/50 Fuel cells
• CPC Class Codes: Y02T 90/40 Application of hydrogen technology to transportation, e.g. using fuel cells

Abstract

The present invention provides a startup sequence control method of fuel cell-super capacitor hybrid electric vehicles, which can protect a fuel cell at the time of the starting of the fuel cell, reduce the start-up time and promote convenience of a driver in a fuel cell-super capacitor serial hybrid system which does not employ a high-voltage power converter. The startup sequence control method comprises the steps of: determining whether or not a low-voltage auxiliary battery is in a state where its voltage is less than a reference voltage or in a cold start condition after a key-on signal has been input; if the auxiliary battery is in the state where its voltage is less than a reference voltage or in the cold start condition, matching the voltage of a main bus terminal to the voltage of an auxiliary power source through the voltage boost of a power converter; turning on a relay for cutting off the voltage of the auxiliary power source and a main relay of a precharge unit for the auxiliary power source; and turning off the power converter and then driving a fuel cell auxiliary component using the auxiliary power source to thereby boost a fuel cell voltage.

Claims

1. A startup sequence control method of a fuel cell-super capacitor hybrid electric vehicle, comprising the steps of:

determining whether or not a low-voltage auxiliary battery is in a state where its voltage is less than a reference voltage or in a cold start condition after a key-on signal has been input;

matching, if the auxiliary battery is in a state where its voltage is less than a reference voltage or in a cold start condition, the voltage of a main bus terminal to the voltage of an auxiliary power source through the voltage boost of a power converter;

turning on a relay for cutting off the voltage of the auxiliary power source and a main relay of a precharge unit for the auxiliary power source; and

turning off the power converter and then driving a fuel cell auxiliary component using the auxiliary power source to thereby boost a fuel cell voltage.

2. The startup sequence control method of claim 1, wherein the step of driving the fuel cell auxiliary component using the auxiliary power source further comprises the steps of:

determining whether the voltage of the auxiliary power source is lower than or equal to a higher one (V_LP1) of the fuel cell voltage V_FC having a level enough to use the power of the auxiliary component from the fuel cell and a minimum voltage needed to drive the auxiliary component;

matching, if the voltage of the auxiliary power source is not lower than or equal to the voltage V_LP1, the voltage of the main bus terminal to the voltage V_LP1 through the voltage boost of the power converter; and

turning off, if the fuel cell voltage is higher than or equal to the voltage V_LP1, the power converter and the main relay.

3. The startup sequence control method of claim 2, further comprising the step of, if the fuel cell voltage is higher than or equal to V_LP1, releasing the connection between the power converter and the auxiliary power source and then driving the fuel cell auxiliary component using the output voltage of the fuel cell itself.

4. The startup sequence control method of claim 3, further comprising the steps of:

charging the auxiliary battery through the buck of the power converter after the completion of the start-up of the fuel cell;

switching on the relay installed at a front end of the MCU to prepare the driving of the vehicle;

entering a single fuel cell mode and charging the fuel cell to a certain voltage level through the adjustment of the duty cycle of the IGBT prior to the switching on of the main relay for interconnecting the fuel cell and the auxiliary power source in order to perform a precharge operation using the auxiliary power source while driving the vehicle in the single fuel cell mode;

determining whether or not the voltage of the fuel cell and the voltage of the auxiliary power source are equal to each other; and

switching, if the voltage of the fuel cell and the voltage of the auxiliary power source are equal to each other, on the main relay of the precharge unit.

5. The startup sequence control method of claim 1, further comprising the steps of:

matching, if it is determined that the auxiliary battery is not in a state where its voltage is lower than a reference voltage or is not in a cold start condition, the voltage of the main bus terminal to V_LP1 through the voltage boost of the power converter;

driving the fuel cell auxiliary component using the auxiliary battery to thereby boost the fuel cell voltage;

turning off, if the fuel cell voltage is higher than or equal to V_LP1, the power converter.

6. The startup sequence control method of claim 5, further comprising the step of, if the fuel cell voltage is higher than or equal to V_LP1, releasing the connection between the power converter and the auxiliary power source and then driving the fuel cell auxiliary component using the output voltage of the fuel cell itself.

7. The startup sequence control method of claim 6, further comprising the steps of:

charging the auxiliary battery through the buck of the power converter after the completion of the start-up of the fuel cell;

switching on the relay installed at a front end of the MCU to prepare the driving of the vehicle;

entering a single fuel cell mode and charging the fuel cell to a certain voltage level through the adjustment of the duty cycle of the IGBT prior to the switching on of the main relay for interconnecting the fuel cell and the auxiliary power source in order to perform a precharge operation using the auxiliary power source while driving the vehicle in the single fuel cell mode;

determining whether or not the voltage of the fuel cell and the voltage of the auxiliary power source are equal to each other; and

switching, if the voltage of the fuel cell and the voltage of the auxiliary power source are equal to each other, on the main relay of the precharge unit.