A fuel cell impedance measurement system and method

Abstract

The invention relates to a fuel cell impedance measurement system and method. The fuel cell impedance measurement system comprises a signal collecting unit, an impedance calculating unit, a system load, a DC-DC power converter and a control unit. The signal collecting unit is used for collecting an electric pile voltage, an electric pile current and a monomer voltage. The impedance calculating unit receives the collected electric pile voltage, electric pile current and monomer voltage, and the impedance of a fuel cell electric pile and the impedance of a single fuel cell are calculated. The DC-DC power converter is arranged between the fuel cell electric pile and the system load and used for increasing an output voltage of the fuel cell electric pile to a system working voltage and superposing a sinusoidal alternating current on a direct current to serve as an excitation current of the impedance. The control unit is connected with the impedance calculating unit, the DC-DC power converter and the system load and used for judging the internal state of the fuel cell according to output of the impedance calculating unit and generating a corresponding PWM control signal by combining theload power demand to send the PWM control signal to the DC-DC power converter. Compared with the prior art, the advantages such as high precision are achieved.

Description

technical field [0001] The invention relates to a fuel cell technology, in particular to a fuel cell impedance measurement system and method. Background technique [0002] Compared with other types of new energy, fuel cells have the characteristics of high conversion efficiency, environmental friendliness, and simple and flexible assembly. Although fuel cells have many advantages, as far as the current reality is concerned, there are still many problems in fuel cells, such as life issues and reliability issues. and cost issues. Among them, reliability is one of the key factors restricting the large-scale application and commercialization of fuel cells. Electrochemical impedance spectroscopy can separate the influence of different electrochemical processes on fuel cells, especially for complex electrochemical systems involving multi-step reactions and parallel reactions. The internal state of the fuel cell can be inferred from the impedance information of the fuel cell, inc...

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Problems solved by technology

This patent specifies the specific implementation method of fuel cell impedance measurement, but the method only calculates the impedance of the fuel cell stack

The fuel cell stack is composed of multiple fuel cell cells. Different cells have different positions in the stack, and there will be inconsistencies in the temperature, gas supply state and even current density of each cell, resulting in inconsistent impedance of the cells. The problem

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