| 摘要 |
<p>A circuit (30) is provided for generating a current that is a harmonic of the frequency of the utility system (12, 34, 160, 220) and which is of a selected amplitude and phase to reduce the total harmonic distortion of a system (10, 42, 136, 170, 236) that converts alternating current to direct current, or vice versa. The DC signal is sampled and by controlling switches (68, 70; 130, 132; 204, 208, 294, 296), a sinusoidal current at the desired harmonic is generated, and is provided to an impedance network (71, 71H, 71K, 150, 218) that injects this current into the multiphase AC system used (260) by the utility in a very low cost, easily controlled, and highly effective manner. The impedance network, (71, 71H, 71K, 150, 218, 260) comprises a single inductor (73A, 73B, 73C) and capacitance (75A, 75B, 75C, 75H, 75I, 75J) connected in series through each of the phases of the utility, with the current signal having an amplitude that is selected to substantially eliminate harmonics which cause high distortion of the utility signal.</p> |
