Abstract: Multi-terminal DC system interconnection where three DC electrical feeds (18-20) are interconnected is shown. Each terminal of each DC feed (18-20) is connected to each of the other terminals through a breaker circuit (21-23). Hence current flows from one terminal of one DC electrical feed, for example (18), to another terminal feed, for example (19), through one breaker circuit (21) rather than two breaker circuits with prior art techniques.

Abstract: A drive circuit for a three-plane load (7) includes an inverter bridge consisting of six bridge switches (T1 to T6), a modulation generator (6) which controls switching of the inverter bridge (4) via a pulse width modulator, in dependence on the inverter line voltage commands (Va, Vb and Vc) and sensed line currents (Ia, Ib and Ic). The pulse width modulation generator is configured such that if the commanded line voltages allow, the phase leg carrying the greater sensed, current is claimed to one of the d.c. rails, the required line voltage controlled by varying the on-to-off duty cycle of the two other bridge legs in accordance with the pulse width modulation (pwm) principle. Clamping suppresses the high frequency switching in the leg (dead-banding) and in the steady state occurs for two sixty-degree segments of the fundamental cycle. The reduction in switching losses associated with the clamping is maximized by linking the dead-band to the peaks of the leg current.