Analysis of DC and AC Choke Effects on Common-Mode Noise Emissions in ASD at the Frequency Range of 9 –150 kHz

Magnetic chokes are conventionally utilized at the DC or AC side of the Adjustable Speed Drives (ASDs) to suppress low order harmonics of 0–2 kHz. Recently, the frequency range of 9–150 kHz has been noticed as a new disturbing frequency range, interfering with the distribution networks. Due to the novelty of this topic, so far, there has not been a thorough investigation for the effect of DC and AC choke configurations on 9–150 kHz emissions, especially for the three-phase ASDs. In this paper, the effect of DC and AC choke configurations on Common-Mode (CM) current emissions at the frequency range of 9–150 kHz is broadly surveyed in the three-phase ASDs. Subsequently, the comprehensive equivalent models of the system are presented for each configuration of DC and AC chokes. This investigation is based on the comparative analysis of the system's transfer functions according to the presented single-phase equivalent model, mathematical calculations, and the three-phase system circuit. Consequently, the presented approach is highly useful to minimize the drive system volume, as the designer can predict the choke configuration of the smallest size for suppressing 9–150 kHz emissions.