Method for determining a maximum power point voltage of a fuel cell and use thereof

A maximum power point, fuel cell technology, applied in fuel cells, fuel cell additives, fuel cell heat exchange, etc., can solve problems such as power generation efficiency decline, fuel cell electrode degradation, and insufficient output power

Inactive Publication Date: 2006-10-04
HITACHI LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

That is to say, in the output characteristics of the fuel cell, there is a maximum power point with the best power generation efficiency, and when it is used beyond this maximum power point, the electrode of the fuel cell may deteriorate due to a decrease in power generation efficiency and insufficient output power.

Method used

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  • Method for determining a maximum power point voltage of a fuel cell and use thereof
  • Method for determining a maximum power point voltage of a fuel cell and use thereof
  • Method for determining a maximum power point voltage of a fuel cell and use thereof

Examples

Experimental program
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Effect test

Embodiment approach 1

[0062] Figure 4 It is a configuration diagram showing a configuration example of the fuel cell control system according to Embodiment 1 of the present invention. This fuel cell control system is roughly divided into a fuel cell 1, an electric double-layer capacitor (EDLC) 2 as an electric storage unit, a circuit unit 3 composed of a step-up converter or a step-down converter, and a counter circuit unit 3 A control IC (power control device) 4 for switching control. This fuel cell control system is applied to portable electronic equipment, and the fuel cell 1 is a direct methanol fuel cell.

[0063] In this fuel cell control system, electric double layer capacitors 2 used as electric storage units each have a withstand voltage of 2.3V to 3.3V. Therefore, if Figure 4 As shown, when two cells are used in series, the withstand voltage is greater than or equal to 4.6V. This fuel cell control system can be applied to portable telephones, Electronic devices such as PDAs (Persona...

Embodiment approach 2

[0094] Figure 8 It is a configuration diagram of a fuel cell control system according to Embodiment 2 of the present invention. In this fuel cell control system using the control IC 4a, this control IC 4a, and Figure 6 Compared with the control IC 4 of the fuel cell control system of the first embodiment shown, the internal structure is different. Circuit section 3a and other structures, with Figure 6 The fuel cell control system shown is the same.

[0095] The control IC 4 a is composed of a control unit 11 a and a reference voltage setting unit 12 . The voltage is divided by the resistor R3 and the resistor R4, and the output voltage of the circuit part 3a input from the storage voltage terminal Fbout is compared with the second reference voltage Vref2 by the differential amplifier S3, and the differential voltage (hereinafter referred to as the output voltage difference) is output to one terminal of the reference voltage setting section 12. The temperature voltage o...

Embodiment approach 3

[0105] Figure 10 It is a configuration diagram of a fuel cell control system according to Embodiment 3 of the present invention. Figure 10 Compared with the fuel cell control systems of Embodiments 1 and 2, the fuel cell control system according to Embodiment 3 shown is not a synchronous rectification type, but a Schottky barrier diode 15 is used instead. The structure of the step-up chopper method. That is, in Figure 10 of circuit section 3b, the Figure 6 The P-channel power MOSFET 14 of the circuit portion 3 a is replaced with a Schottky barrier diode 15 . By adopting this structure, with Figure 6 Embodiment 1 of and Figure 8 Compared with the structure of Embodiment 2, it is effective for the case where the voltage at the output terminal is higher.

[0106] next to Figure 10 The control IC 4b of Embodiment 3 shown will be described in detail. The control IC 4b of Embodiment 3, and Figure 4 and Figure 6 The control IC 4 of Embodiment 1 shown and Figure 8...

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Abstract

A detection voltage, which is obtained by dividing the voltage of a fuel cell 1 by resistors, is compared with a first reference voltage Vref 1 by a differential amplifier. The differential voltage is input to a control section. The control section performs PWM control for the circuit section according to the difference. The first reference voltage Vref 1 is set according to the dividing ratio of the resistors, based on the output voltage when the fuel cell generates power at the maximum power point. To determine the output voltage for maximum power generation, a characteristic curve representing a current-voltage characteristic is approximated by an approximating line within a range excluding an area in which the output voltage changes abruptly when the output current is nearly zero, and an extrapolated voltage is obtained on the extension line of the approximating line at an output current of zero. Fifty percent of the extrapolated voltage is then determined as the output voltage when the fuel cell generates power at the maximum power point. Thus, a fuel cell control system that identifies a highly precise output voltage for power generation at a maximum power point and controls power so that the maximum power point is not exceeded could be provided.

Description

technical field [0001] The invention relates to a method for determining the maximum power point voltage of a fuel cell, a fuel cell control system and a power control device used in the fuel cell control system. Background technique [0002] Due to advances in electronic technology in recent years, portable electronic devices such as mobile phones, notebook PCs (personal computers), audio-video devices, and mobile terminal devices have rapidly spread. Secondary batteries used as power sources for these portable electronic devices have progressed from the existing sealed lead batteries to Ni / Cd batteries, Ni-hydrogen batteries, and Li-ion batteries through the development of battery active materials and the development of high-capacity battery structures. Batteries, trying to increase capacity. [0003] On the other hand, in portable electronic devices, efforts are being made to achieve low power consumption, and the power consumption of each function in the device is great...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01M8/00
CPCY02E60/50Y02E60/523H01M8/04559H01M8/04626H01M2008/1095H01M8/04567H01M8/04947H01M8/1011H01M8/04597H01M8/04619H01M8/04888H01M8/04365H01M8/0494H01M8/04007H01M8/0488
Inventor 乘松泰明叶田玲彦菊地睦
Owner HITACHI LTD
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