An improved synchronization control scheme of a low cost 400Hz power supply for No-Break Power Transfer

This paper proposes an improved synchronization control scheme of a low cost 400 Hz power supply for no-break power transfer. In the case of aircraft application, the 400 Hz power supply called as ground power units (GPU) has been accepted as external electrical power system during stopovers in ground. When transferring from one power source to the other, there is a momentary break in supply. To transfer without a break, the two power sources are momentarily connected in parallel. The proposed synchronization control is achieved by connecting an existing synchronization bus to a voltage zero-crossing signal of a generator power with discrete logic ICs and analog circuits. Therefore, this proposed control scheme is rather simple and the cost may be decreased, compared with expensive controller such as DSP and CAN. The practical feasibility of the proposed control scheme is proved by simulation.