Power supply system and fuel cell vehicle

Patent metadata

Field	Value
Publication number	US-9796270-B2
Application number	US-201514731410-A
Country	US
Kind code	B2
Filing date	Jun 5, 2015
Priority date	Jul 3, 2014
Publication date	Oct 24, 2017
Grant date	Oct 24, 2017

Abstract

A power supply system includes a fuel cell, a power storage device, a first voltage adjusting device, a second voltage adjusting device, and a controller. The controller is to control the first voltage adjusting device and the second voltage adjusting device. The controller is to switch the second voltage adjusting device from a direct coupling state to a voltage adjusting state in a case where a first absolute value of a first difference between a secondary voltage of the second voltage adjusting device applied across a load and a fuel cell voltage is less than a predetermined allowable voltage value or in a case where a second absolute value of a second difference between a fuel cell current being to flow from the fuel cell into the first voltage adjusting device and a target current value of the fuel cell current exceeds a predetermined allowable current value.

First claim

What is claimed is:

1. A power supply system comprising:
a fuel cell that outputs a fuel cell voltage;
a power storage device that outputs a power storage device voltage;
a load;
a first voltage adjusting device that adjusts the fuel cell voltage and applies the adjusted fuel cell voltage to the load;
a second voltage adjusting device that adjusts the power storage device voltage and applies the adjusted power storage device voltage to the load; and
a controller that controls the first voltage adjusting device and the second voltage adjusting device, wherein
when an absolute value of a difference between a secondary voltage at the load in the second voltage adjusting device and the fuel cell voltage is less than a predetermined allowable voltage value or when an absolute value of a difference between a fuel cell current flowing from the fuel cell into the first voltage adjusting device and a command value of the fuel cell current exceeds a predetermined allowable current value, the controller switches the second voltage adjusting device from a direct coupling state to a voltage adjusting state.

2. The power supply system according to claim 1 , wherein
after the controller has switched the second voltage adjusting device from the voltage adjusting state to the direct coupling state while maintaining the first voltage adjusting device in a voltage adjusting state,
the controller switches the second voltage adjusting device from the direct coupling state to the voltage adjusting state when the absolute value of the difference between the secondary voltage and the fuel cell voltage is less than the allowable voltage value.

3. The power supply system according to claim 1 , further comprising:
a first voltage sensor that detects the fuel cell voltage; and
a second voltage sensor that detects the secondary voltage, wherein
the allowable voltage value is a sum of a measurement error of the first voltage sensor and a measurement error of the second voltage sensor.

4. The power supply system according to claim 1 , wherein
after the controller has switched the second voltage adjusting device from the voltage adjusting state to the direct coupling state while maintaining the first voltage adjusting device in a voltage adjusting state,
the controller switches the first voltage adjusting device from the voltage adjusting state to a direct coupling state while maintaining the second voltage adjusting device in the direct coupling state, and
the controller switches at least the second voltage adjusting device from the direct coupling state to the voltage adjusting state when the absolute value of the difference between the fuel cell current and the command value exceeds the allowable current value.

5. The power supply system according to claim 4 , wherein in a case where the controller switches the second voltage adjusting device from the direct coupling state to the voltage adjusting state, the controller sets a sum of either the fuel cell voltage or the power storage device voltage and an allowable value of a control error of the secondary voltage at a command value of the secondary voltage.

6. The power supply system according to claim 1 , wherein
the first voltage adjusting device is a boost converter that boosts the fuel cell voltage to a secondary voltage and applies the secondary voltage to the load, and
when the absolute value of the difference between the secondary voltage of the second voltage adjusting device and the fuel cell voltage is less than the allowable voltage value or when the absolute value of the difference between the fuel cell current and the command value exceeds the allowable current value, the controller switches the second voltage adjusting device from the direct coupling state to a boost state.

7. A fuel cell vehicle comprising:
the power supply system according to claim 1 ; and
a driving motor included in the load of the power supply system.

8. A power supply system comprising:
a fuel cell to output a fuel cell voltage;
a power storage device to output a power storage device voltage;
a first voltage adjusting device to adjust the fuel cell voltage to generate an adjusted fuel cell voltage to be applied to a load;
a second voltage adjusting device having a direct coupling state and a voltage adjusting state, the power storage device voltage being adjusted to generate an adjusted power storage device voltage to be applied to the load in the voltage adjusting state, the power storage device voltage being applied to the load without adjusting the power storage device voltage in the direct coupling state; and
a controller to control the first voltage adjusting device and the second voltage adjusting device, the controller being to switch the second voltage adjusting device from the direct coupling state to the voltage adjusting state in a case where a first absolute value of a first difference between a secondary voltage of the second voltage adjusting device applied across the load and the fuel cell voltage is less than a predetermined allowable voltage value or in a case where a second absolute value of a second difference between a fuel cell current being to flow from the fuel cell into the first voltage adjusting device and a target current value of the fuel cell current exceeds a predetermined allowable current value.

9. The power supply system according to claim 8 ,
wherein the first voltage adjusting device has a first voltage adjusting state in which the fuel cell voltage is adjusted to generate the adjusted fuel cell voltage to be applied to the load, and
wherein after the controller has switched the second voltage adjusting device from the voltage adjusting state to the direct coupling state while maintaining the first voltage adjusting device in the first voltage adjusting state, the controller switches the second voltage adjusting device from the direct coupling state to the voltage adjusting state in a case where the first absolute value of the first difference between the secondary voltage and the fuel cell voltage is less than the predetermined allowable voltage value.

10. The power supply system according to claim 8 , further comprising:
a first voltage sensor to detect the fuel cell voltage; and
a second voltage sensor to detect the secondary voltage,
wherein the predetermined allowable voltage value is a sum of a measurement error of the first voltage sensor and a measurement error of the second voltage sensor.

11. The power supply system according to claim 8 ,
wherein the first voltage adjusting device has a first voltage adjusting state in which the fuel cell voltage is adjusted to generate the adjusted fuel cell voltage to be applied to the load,
wherein the first voltage adjusting device has a first direct coupling state in which the fuel cell voltage is applied to the load without adjusting the fuel cell voltage, wherein after the controller has switched the second voltage adjusting device from the voltage adjusting state to the direct coupling state while maintaining the first voltage adjusting device in the first voltage adjusting state, the controller switches the first voltage adjusting device from the first voltage adjusting state to the first direct coupling state while maintaining the second voltage adjusting device in the direct coupling state, and
wherein the controller switches at least the second voltage adjusting device from the direct coupling state to the voltage adjusting state in a case where the second absolute value of the second difference between the fuel cell current and the target current value exceeds the predetermined allowable current value.

12. The power supply system according

Assignees

• Honda Motor Co Ltd

Inventors

• Kazuno Shuichi
• Shimizu Kenichi
• Sakai Yasutaka
• Shirasaka Takuya
• Higashitani Kosuke

Classifications

• H01M10/48

  Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte (constructional details of current conducting connections for detecting conditions inside cells or batteries, e.g. details of voltage sensing terminals, H01M50/569) · CPC title

• B60L2210/14

  Boost converters · CPC title

• B60L2240/527

  Voltage · CPC title

• B60L2240/549

  Current · CPC title

• H01M8/04559

  of fuel cell stacks · CPC title