Stationary state error reduction on the electrical modelling of high pressure sodium lamps

This study presents an improvement in the steady-state error reduction in the electrical modelling of high pressure sodium (HPS) lamps when they exhibit high non-linear behaviour. An electrical expression of the lamp is resistance could be obtained from the Saha equation, which is sufficient to represent the behaviour of several high intensity discharge lamps with low non-linear behaviour, but if the modelled lamp possess high non-linear operation, as do some HPS lamps, a large stationary error between the simulation and experimental results is obtained. Therefore an enhanced expression of lamp resistance is proposed here to reduce this error. Parameters are obtained from the measurements of electrical variables such as power, current and voltage, in the lamp. The proposal can be used to simulate the non-resonant ballast. Experimental and simulation results are shown.