On-line diagnostic of a PEM fuel cell stack based on the electrical power converter

Transcription

1 International Symposium on Diagnostic Tools for Fuel Cell Technologies Trondheim, June 24th, 2009 On-line diagnostic of a PEM fuel cell stack based on the electrical power converter Dr. Abdellah NARJISS, Dr. Frédéric GUSTIN, Dr. Daniel DEPERNET, Prof. Daniel HISSEL University of Franche-Comte (France)

2 Introduction General architecture of a PEM Fuel Cell system Gases Fuel Cell System Fluidic supervision Ancillaries Fuel Cell Stack Power converter Load On-line diagnostic How to optimize the FC behavior? Control Electrical supervision Objective : design an on-line diagnostic tool dedicated to automotive applications

3 Outlines 1) Choice and sizing of the power converter 2) Real time control strategy 3) On-line impedance spectrometry 4) Conclusions

4 Choice and sizing of the power converter PEM FC Stack : 115V (0A) 55V (560A) DC Bus : 540V Power converter High voltage elevation ratio Transportation applications 80kW ECCE Hybrid Electrical Vehicle Improvement of durability and reliability of PEMFC in embedded applications Control of DC-link with high transformation ratio, low switch constraints and high efficiency Optimization of size and cost

5 Choice and sizing of the power converter General description of the energy conversion scheme Semi-conductors : Mosfets + Diodes F PWM =50kHz Planar technology transformer

6 Choice and sizing of the power converter Sizing of the power converter for impedance spectrometry F SPECTRO F PWM FC Stack Power converter DC bus ΔIe ΔIs Sizing of the passive filters Is 1 VS 1 Cf α Lf α f 0 Hz ΔVs 2.f ΔI 2.f S L f. C f F PWM = 50kHz F SPECTRO : 1Hz to 2,5kHz

7 Outlines 1) Choice and sizing of the power converter 2) Real time control strategy 3) On-line impedance spectrometry 4) Conclusions

8 Real time control Impedance spectrometry done by the power converter Current injection α 1 A α = α 0 +A.sin(ωt) Δα α 0 0 α 0 : duty cycle => normal behavior A : sinusoïdal modulation amplitude F injection F PWM = 50kHz FPWM 20 k => F injection_max = 2,5kHz t sinus de 20 points High resolution quality

9 Real time control Impedance measurement extraction of ripple PWM rejection filtering and phase referencing of desired ripple with DFT (Discrete Fourier Transform) harmonic impedance Fuel Cell Voltage Fuel Cell Current Re(Vk) Im(Vk) Zk Re(Ik) Im(Ik) Analogical extraction of ripple Sampling (PWM rejection) DFT Module ratio Phase difference

10 Real time control Electrical behavior experimental results (1kW prototype) Electrical behavior good DC bus voltage stability power flows control ability

11 Outlines 1) Choice and sizing of the power converter 2) Real time control strategy 3) On-line impedance spectrometry 4) Conclusions

12 On-line impedance spectrometry Injection strategy of fuel cell stimulus duty cycle sinusoidal modulation control of the current ripple amplitude Constant nominal Current ripple duty cycle reference + + Ripple + controller - Current ripple measurement DC/DC converter Current + measurement Fuel Cell - Continuous component of current Continuous component extractor

13 On-line impedance spectrometry UBZM PEM 20-cell stack Experimental values Gas flows 20A FC stack temperature 48 C FC air dew point 45 C FC stack voltage 14,18V FC current 12,15A Air hygrometry level 85% Hydrogen hygrometry 20% level Load current 1,6A -Im (Ohm) 0,05 0,045 0,04 0,035 0,03 0,025 0,02 0,015 0,01 0,005 On-line impedance spectrometry result essai_1 essai_2 500Hz 2Hz 0-0,005 0,1 0,15 0,2 0,25 0,3 Re (Ohm) Results reproducibility highest quality

14 On-line impedance spectrometry Influence of the spectrometry on the DC bus voltage Impact Effects de la spectroscopie of spectroscopy d impédance on continuous sur la stabilité voltage du bus continu Vbus (Volts) F = 2 Hz F = 30 Hz F = 360 Hz 20 0 phase (radians) ΔVmax Fmin and ΔVmax < 10% Vbus

15 On-line impedance spectrometry Effect of the gas hydration level Fuel cell operating point : 8A, T FC =48 C, Igases=20A -Im (Ohm) 0,07 0,06 0,05 0,04 0,03 0,02 0,01 Tr=25 C, HR_air=30%, HR_H2=21% Tr=35 C, HR_air=50%, HR_H2=20% Tr=45 C, HR_air=87%, HR_H2=20% Humidification level increases Z stack diminishes 0 0,05-0,01 0,15 0,25 0,35 0,45 Re (Ohm)

16 On-line impedance spectrometry Effect of the H 2 gas flow Fuel cell operating point : 8A 0,07 0,06 H 2 flow increases 0,05 -Im (Ohm) 0,04 0,03 0,02 Igas=20A Igas=15A Igas=10A Z stack diminishes in LF 0,01 0 0,1 0,15 0,2 0,25 0,3 0,35 Re (Ohm)

17 Outlines 1) Choice and sizing of the power converter 2) Real time control strategy 3) On-line impedance spectrometry 4) Conclusions

18 Conclusions Many advantages : Important power flows transfer ability Ability to high transformation ratios High compactness On-line diagnosis ability Ability to modify in real time the FC control laws to improve durability / efficiency Next to do : Higher power FC have to be considered Go from the impedance spectrometry to the FC stack on-line diagnosis Consider SOFC power plants

19 To go further [1] Hissel, D., Jemeï, S., Hubert, V., François, X., Péra, M.C., Kauffmann, J.M., A diagnosisoriented model of a fuel cell power generator dedicated to automotive applications, ISNGVT'01 4th International Symposium on Next Generation Vehicle Technology, pp , Gwangju, South Korea, [2] Hissel, D., Péra, M.C., Kauffmann, J.M., Automotive fuel cell power generators diagnosis, Journal of Power Sources, vol. 128, n 2, pp , [3] Hissel, D., Candusso, D., Harel, F., Fuzzy clustering durability diagnosis of embedded polymer electrolyte fuel cells, IEEE Transactions on Vehicular Technology, vol. 56, n 5, pp , [4] Narjiss, A., Depernet, D., Gustin, F., Hissel, D., Berthon, A., Design of a high efficiency fuel cell DC/DC converter dedicated to transportation applications, ASME Fuel Cell Science and Technology, vol. 5, n 4, 11p., [5] Steiner, N., Candusso, D., Hissel, D., Hernandez, A., Moçoteguy, Ph., Aslanides, A., A review of PEM voltage degradation associated with water management: impacts, influent factors and characterization, Journal of Power Sources, vol. 183, n 1, pp , 2008.

20 International Symposium on Diagnostic Tools for Fuel Cell Technologies Trondheim, June 24th, 2009 On-line diagnostic of a PEM fuel cell stack based on the electrical power converter Dr. Abdellah NARJISS, Dr. Frédéric GUSTIN, Dr. Daniel DEPERNET, Prof. Daniel HISSEL University of Franche-Comte (France)