Classifications

• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
  • G05B23/00—Testing or monitoring of control systems or parts thereof
  • G05B23/02—Electric testing or monitoring
  • G05B23/0205—Electric testing or monitoring by means of a monitoring system capable of detecting and responding to faults
  • G05B23/0218—Electric testing or monitoring by means of a monitoring system capable of detecting and responding to faults characterised by the fault detection method dealing with either existing or incipient faults
  • G05B23/0221—Preprocessing measurements, e.g. data collection rate adjustment; Standardization of measurements; Time series or signal analysis, e.g. frequency analysis or wavelets; Trustworthiness of measurements; Indexes therefor; Measurements using easily measured parameters to estimate parameters difficult to measure; Virtual sensor creation; De-noising; Sensor fusion; Unconventional preprocessing inherently present in specific fault detection methods like PCA-based methods

Definitions

• the invention relates generally to dynamic system control techniques.
• the invention relates, according to a first aspect, to a method for monitoring at least one basic physical parameter that is at least partially representative of an operation of a physical dynamic system, this method comprising a measurement operation. .
• the operating state of a fuel cell depends very critically on its internal temperature, that is to say more precisely the temperature of the stack that its cells form, this temperature not being practice not directly measurable.
• a traditional approach in monitoring and fault diagnosis is to provide a physical redundancy of the measuring and control devices, that is to say to multiply the number of sensors, actuators and computers.
• the invention aims to propose an approach that, while allowing the identification of possible failures, offers an alternative to the path of a systematic physical redundancy.
• the method of the invention which moreover complies with the generic definition given in the preamble above, is essentially characterized in that the measurement operation consists in obtaining, by means of a set of m, where m is an integer greater than two, a set of m corresponding measurements respectively representative of m measurable physical parameters related to the first basic physical parameter, and in that this method further comprises an analysis operation consisting in less to develop a dispersion quantity whose value is representative of a dispersion of the m measurements, a control operation of comparing the value of the dispersion quantity with a threshold defined for normal operation of the dynamic system, a diagnostic operation to conclude that an anomaly exists in the event of the threshold being exceeded by the dispersion quantity, and a purification operation consisting at least in identifying and discarding, in the event of an anomaly, that of the m measures which has the greatest contribution to the value of the dispersion quantity.
• the analysis operation comprises the determination of a residual vector defined as the product of a weighting matrix by a measurement vector having said measurements for components, the matrix a weighting factor having a norm equal to unity, each component of the residue vector being constituted by a corresponding linear combination of said measurements, obtained by weighting these measurements by means of zero average weighting coefficients of the weighting matrix, and said size of dispersion being constituted by the standard of the vector of residues.
• the analysis operation comprises determining, as a dispersion quantity, a global standard deviation of the set of m measurements with respect to an average value of these measurements. measures.
• the invention relates to a fuel cell comprising an anode, a cathode and a cooling circuit, this cell being characterized in that it comprises first, second and third temperature sensors respectively delivering first, second and third temperature measurements and respectively disposed on its cathode, on its cooling circuit, and on its anode, this battery comprising in in addition to a data processing circuit adapted to implement, on these first, second and third temperature measurements, a method according to any one of the embodiments mentioned above for estimating an internal temperature of this battery.
• the invention particularly relates to a method for monitoring one or more basic physical parameters associated with the operation of a physical dynamic system, these parameters reflecting the operation of this system and therefore being able to influence the latter when they are taxed.
• Such a battery comprises, in a manner known per se, a stack 10 of cells, a cathode 11 fed by an air compression unit 41, an anode 13 supplied with hydrogen by a reformer 43, and a cooling circuit 12.
• the invention proposes to develop, by means of three sensors referenced 21 to 23, three corresponding measurements Tc, Tr, and Ta respectively representative of the three temperatures ⁇ c, ⁇ r, and ⁇ a respectively taken by the gas supplying the cathode 11, the liquid at the outlet of the cooling circuit 12 and the gas supplying the anode 13.
• the stack 10 the cathode 11, the cooling circuit 12, and the anode 13 adopt respective temperatures ⁇ 10, ⁇ c, ⁇ r, and ⁇ a which are necessarily related to each other.
• the battery of the invention comprises a data processing circuit 3 adapted to receive the temperature measurements Tc, Tr, and Ta, and to output a quantity T10 representing an estimate of the internal temperature ⁇ 10 of the battery 1.
• the magnitude T10 may be constituted by a linear combination, or any other suitable function, of the measurements Tc, Tr, and Ta provided that these measurements have a sufficient degree of reliability.
• An essential part of the invention is precisely to evaluate this degree of reliability, and to rule out any suspicious measurement among the measurements Tc, Tr, and Ta.
• the method of the invention in its part implemented in the circuit 3, comprises firstly a analysis operation, consisting in developing a dispersion quantity whose value is representative of the dispersion of the different temperature measurements Tc, Tr, and Ta.
• the dispersion quantity which will be denoted S in a first embodiment described hereinafter, and ⁇ in a second embodiment also described hereinafter, has a value which is all the greater as the three measurements of temperature Tc, Tr, and Ta are less close to each other.
• the method of the invention then comprises a control operation, which consists in comparing the value of the dispersion quantity, S or ⁇ , with a corresponding threshold, denoted Sseuii or ⁇ seuii, this threshold being defined for normal operation of the dynamic system. what constitutes the stack 1.
• the method of the invention then comprises a diagnostic operation, which consists in concluding in an anomaly if the threshold Sseuii or ⁇ seuii is exceeded by the corresponding dispersion quantity, S or ⁇ .
• the method of the invention comprises a purification operation, which is implemented in the event of an anomaly, and which consists in identifying and discarding that of the measurements Tc, Tr, and Ta which has the greatest contribution to the value of the dispersion quantity S or ⁇ .
• the circuit 3 modifies its standard algorithm for estimating the temperature ⁇ 10 to no longer take into account the measurement Tc, Tr, or Ta previously discarded.
• a state variable x dependent on the time t
• a fault vector f dependent on the time fc (vector unknown, but equal to zero in the absence of failure)
• a weighting matrix V is further defined such that:
• the analysis operation comprises the determination of a residue vector r as a function of time t and defined as the product V.y of the weighting matrix V by the measurement vector y.
• each of the components of the residual vector r here in number 2 is constituted by a corresponding linear combination of measures such as Tc, Tr, Ta, obtained by a weighting of these measurements by means of Zero-weighting coefficients of the weighting matrix V.
• the dispersion quantity S is constituted by the standard of the residue vector r, namely:
• the purification operation first comprises the determination, for each measurement, of a scalar residue corresponding to the cathode, cooling, ranode defined as the product, by the residue vector r, of a vector Vj . ⁇ taken from the transposed weighting matrix V ⁇ and relating to this measurement, this operation leading, in this case, to:
• the purification operation continues by removing the measure which corresponds to the scalar residue whose absolute value is the highest.
• the analysis operation comprises determining, as a dispersion quantity, a global standard deviation ⁇ of the set of m measurements Tc, Tr, Ta with respect to the average value T of these measurements. -to say :

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• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Automation & Control Theory (AREA)
• Fuel Cell (AREA)

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Citations (6)

• 2004
  • 2004-06-21 FR FR0406710A patent/FR2871949B1/fr not_active Expired - Fee Related
• 2005
  • 2005-05-12 JP JP2007516009A patent/JP4912297B2/ja not_active Expired - Fee Related
  • 2005-05-12 WO PCT/FR2005/050315 patent/WO2006005858A1/fr active Application Filing

Patent Citations (6)

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