Analysis of three-phase rectifiers with constant-voltage loads

This work presents a quantitative analysis of the operating characteristics of three-phase diode bridge rectifiers with AC-side reactance and constant-voltage loads. We focus on the case where the AC-side currents vary continuously (continuous ACside conduction mode). This operating mode is of particular importance in alternators and generators, for example. Simple approximate expressions are derived for the line and output current characteristics as well as the input power factor. Expressions describing the necessary operating conditions for continuous AC-side conduction are also developed. The derived analytical expressions are applied to practical examples and both simulations and experimental results are utilized to validate the analytical results. It is shown that the derived expressions are far more accurate than calculations based on traditional constant-current models.