Electrical Model for HPS Discharge Based on the Energy-Balance Equation

In this paper, an electrical model for a high- pressure sodium discharge based on the energy-balance equation is presented. A database containing the transport-coefficient values for different temperatures and pressures was used to solve the energy-balance equation. The resultant model is implemented in SIMULINK as a two-terminal device, providing a powerful tool for simulating the electrical-discharge behavior at low and high frequencies under different power requirements. This model reveals that the temperature depth modulation is very low when the current source has a square waveform, even at low frequencies. The model was validated with experimental results. Finally, in order to decrease the complexity and the computing time of the electrical-discharge characteristics, an approximation of the used database is proposed, obtaining very acceptable results.