BOND GRAPH MODELING AND SIMULATION OF SPICE-POUNDING MACHINES FED FROM A PHOTOVOLTAIC SOURCE

The dynamics of intermittent load systems fed from a PV source are exp lored, led by the expanding application of PV power in diverse areas. Most actual loads in small-scale village industry are intermittent and pulsating. For successful application of photovoltaics in these areas , the dynamical behaviour of such systems must be understood. This req uires the formulation of dynamical models of PV-fed intermittent load systems. Bond graph methodology has recently emerged as a very conveni ent tool for dynamic modelling. This is the first application of this methodology in modelling photovoltaic systems. The spice-pounding oper ation is taken as a typical example of a pulsating load that can be fe d from PV power. It is shown that the standard equivalent circuit of t he PV cell gives rise to algebraic looping problems when expressed in the language of the bond graph, Means of overcoming the problem have b een suggested. This is the first report of modelling the spice-poundin g machine with the bond graph technique. The model has been simulated with COSMO-KGP software (developed at the I.I.T., Kharagpur, India) an d the results reported. It is found that the dynamic behaviour of the PV-fed spice-pounding system differs significantly from that of a syst em fed from a constant voltage supply. Performance is compared for a s hunt motor, a series motor and a separately excited motor, and three t ypes of cam profiles, namely parabolic, cycloidal and half harmonic pl us constant velocity. (C) 1997 by John Wiley & Sons, Ltd.