Open-Delta Auto-Connected Electronic Transformer (OD-ACET) based multi-pulse rectifier systems

This paper proposes an Open-Delta Auto-Connected Electronic Transformer (OD-ACET) for 12 and 24-pulse rectifier systems. This approach employs two static converters to operate an OD-ACET at higher than utility line frequencies and to provide multi-pulse operation. By operating magnetic components at a higher frequency, higher power density can be achieved. A unique feature of the proposed approach is that the magnetic components for the DC-side are also exposed to a higher frequency and these components too are reduced in size. The switching frequency and its harmonic components are absent in the utility input line current. The VA ratings of the OD-ACET and static converter are 0.236/0.292 pu and 0.11/0.18 pu in 12 and 24-pulse rectifier systems, respectively. A finer grade of steel or alternatives can be deployed to performance and reduce size further. Analysis, simulations, design example, and experimental results for a 480 V 10 kVA prototype system are presented.