Abstract: Sets of phase shifting interphase transformers are used to combine the outputs of six-pulse static inverter stages to generate harmonic neutralized outputs with higher pulse counts. The phase shifting interphase transformers have a primary winding and at least one secondary winding. For phase shifting interphase transformers having a single secondary winding, a tap on the primary winding is connected through the secondary windings on one of the other phase shifting interphase transformers to produce a combined output having a displacement factor which preserves the displacement factors of the inputs. When the phase shifting interphase transformer has two secondary windings, the tap on the primary is a center tap which is routed through secondary windings on each of the other two phases. Higher pulse count inverters are constructed by combining outputs of the phase shifting interphase transformers with additional shifting interphase transformers to generate a combined output.

Abstract: A high power inverter pole for a voltage sourced inverter suitable for providing compensation in electric power transmission and distribution systems, has a positive switching valve and a negative switching valve connected between closely spaced dc-source terminal, respectively, and a common ac terminal to form a current loop with minimum loop area thereby reducing stray loop inductance and limiting the overshoot voltage on serially connected electronic switches which make up the valves. In a preferred embodiment, the valves are mounted on opposite sides of the web of an insulative I-beam. The electronic switches are incorporated in modular switching units connected in series by C-channel connecting conductors having flanges bolted to the I-beam flanges. The modular units include broad, flat conductors bolted through end flanges to the C-channel connecting conductors. The electronic switches and anti-parallel diodes of the modular units are clamped between these broad, flat conductors.