For three-phase rectification with capacitive DC-smoothing and connection to the low voltage distribution network a rectifier circuit with 18-pulse characteristic and constant DC-voltage output is presented. This circuit avoids unwanted harmonics, especially of order 11, 13, 17 and 19. To get the desired 18-pulse performance, the line-side interphase transformer (LIT) and the current dividing transformer (CDT) connections without isolation are presented. This circuit is characterised by nearly sinusoidal line currents and low costs. At nominal conditions the harmonic distortion factor of the line currents is less than 5% and the power factor is higher than 97%. The circuit only consists of three line-commutated three-phase diode rectifier bridges and few moderate sized magnetic components. The principle of work, simulation and experimental results of a 2kW rectifier with LIT and CDT system are presented too.
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