Quasi 12-pulse rectifier for adjustable speed drives

This paper presents a quasi 12-pulse rectifier scheme for standard adjustable speed drives (ASDs). An analysis of the standard diode rectifier shows that the harmonic currents to some degree are independent of the load. As a result, near true 12-pulse rectifier line currents for a wide load range can be achieved with the quasi 12-pulse scheme. Furthermore, it is shown that the harmonic performance of the quasi 12-pulse scheme actually is superior to the true 12-pulse rectifier if the supply voltage is pre-distorted. Both simulations and experimental results are verifying the analysis.