State Variables Estimation of Fuel Cell—Boost Converter System Using Fast Output Sampling Method

Abstract

Original scientific paperEstimation of state variables of a peak current mode (PCM) controlled DC-DC boost converter supplied by a PEM fuel cell is described in this paper. Since this system is highly nonlinear and non-minimum phase, its state variables are estimated by using fast output sampling method. Estimated state variables are the converter output voltage and its first derivative, and they are suitable for model reference adaptive control or sliding mode based control techniques. The estimator has been designed in a way that it gives a good estimate of the state variables in the continuous and in the discontinuous conduction mode of the converter, and in the presence of measurement and process noise caused by converter switching-mode operation. Experimental results of estimating the state variables on a 450 W boost converter supplied by the emulator of the PEM fuel cell BCS 64-32 show good results of the estimation, regardless of the conduction mode of the converter, i.e. the operating point determined by its output current.Key words: state-space variables, estimation, fast output sampling, peak current mode control, boost converter, step-up converter, PEM fuel cell Procjena varijabli stanja sustava s gorivnimčlankom i uzlaznim pretvaračem metodom brzog uzorkovanja signala. U ovom radu obradena je procjena varijabli stanja sustava s istomjernim uzlaznim pretvaračem u vršnom strujnom načinu upravljanja napajanim PEM gorivnimčlankom. Budući da je taj sustav izrazito nelinearan te neminimalno-fazan, za procjenu njegovih varijabli stanja upotrebljena je metoda brzog uzorkovanja izlaznog signala. Procjenjene varijable stanja su izlazni napon uzlaznog pretvarača te njegova prva derivacija, te su pogodne za adaptivno upravljanje s referentnim modelom i upravljanje temeljeno na kliznim režimima. Procjenitelj je projektiran na način da daje dobru procjenu varijabli stanja u kontinuiranom i diskontinuiranom režimu rada pretvarača, te u uvjetima mjernog i procesnog šuma uzrokovanog sklopnim načinom rada pretvarača. Eksperimentalni rezultati procjene varijabli stanja na uzlaznom pretvaraču snage 450 W napajanim emulatorom gorivnogčlanka BCS 64-32 pokazuju dobre rezultate procjene, neovisno o režimu rada pretvarača, odnosno radnoj točki odredenoj njegovom izlaznom strujom.Ključne riječi: varijable stanja, procjena, brzo uzorkovanje signala, vršno strujno upravljanje, istosmjerni uzlazni pretvarač, PEM gorivničlanak

Adaptive Control of Peak Current Mode Controlled Boost Converter Supplied by Fuel Cell

“…The block schematics of the adaptive system with nonlinear models of the fuel cell BCS 64-32 and PCM boost converter, with a fast output sampling (FOS) estimator of state variables [21,40], for the simulation in MATLAB-SIMULINK is shown in Fig. 17.…”

“…In the LabVIEW software environment the adaptive controller with reduced order reference model and signal adaptation algorithm, and with the FOS estimator of the state variables [21,40], is implemented for application in a National Instruments CompactRIO 9024 FPGA hardware system. The adaptive algorithm is realized with the sample time τ=30 μs.…”