Fuel cell system having a control unit for measuring impedance
AssigneeToyota Jidosha Kabushiki Kaisha
InventorsKota Manabe, Masahiro Shige
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Abstract
There is provided a fuel cell system in which a constantly accurate impedance measurement is made possible regardless of a response characteristic of the voltage converting device. A superimposed signal analysis section analyzes an impedance measuring signal after passing through a DC/DC converter to thereby notify a superimposed signal amplitude control section of an analysis result. A superimposed signal amplitude control section controls an amplitude value of the impedance measuring signal generated by a superimposed signal generating section based on the result notified from the superimposed signal analysis section.
Claims2
A fuel cell system including:
- a fuel cell;
- an electric accumulator interposed in a discharge path of the fuel cell and connected in parallel to the fuel cell;
- and
- a DC/DC voltage converting device connected between the electric accumulator and the fuel cell, the DC/DC voltage converting device having a reactor;
- wherein the fuel cell system includes a control unit, the control unit further comprising:
- a voltage instruction signal generating section for superimposing an impedance measuring signal on an output target voltage of the DC/DC voltage converting device and outputting the voltage to the DC/DC voltage converting device, when an impedance of the fuel cell is measured by using an AC impedance method;
- a state detection section for judging a state of a response characteristic of the DC/DC voltage converting device during the impedance measurement;
- a superimposed signal control section programmed to control an amplitude of the impedance measuring signal based on the state of the response characteristic of the DC/DC voltage converting device judged by the state detection section,
- a measuring device for measuring a reactor current of the DC/DC voltage converting device;
- and
- a first storage device for storing a response characteristic map to judge from the reactor current of the DC/DC voltage converting device whether or not the response characteristic of the DC/DC voltage converting device is in a stable state;
- wherein
- the state detecting section compares a measurement result of the measurement device with the response characteristic map to judge the stable state of the response characteristic;
- and
- the superimposed signal control section programmed to perform a control so that the amplitude of the impedance measuring signal in a case where the response characteristic of the DC/DC voltage converting device is in an unstable state is larger than that of the impedance measuring signal in a case where the response characteristic of the DC/DC voltage converting device is in the stable state.
Dependencies are inferred from the claim text.