초록 ▼

A ground power unit capable of no-break power transfer includes a rectifier for converting power from commercial mains to direct current, a switching circuit, a power transformer, and a pattern generator for controlling the operation of the switching circuit. Voltage and current sensors monitor whet

A ground power unit capable of no-break power transfer includes a rectifier for converting power from commercial mains to direct current, a switching circuit, a power transformer, and a pattern generator for controlling the operation of the switching circuit. Voltage and current sensors monitor whether the phase of the ground power unit is leading or lagging the phase of the aircraft power bus at the tinge of power transfer. The frequency and phase of the pattern generator converter is adjusted to bring the two systems into alignment quickly, well before the power transfer operation is completed. The ground power unit limits the power transfer between the two systems to prevent the overloading of either.

대표청구항 ▼

An external power supply for use in a no-break power transfer connection to an active aircraft power bus provided with power from an internal aircraft power source, and a power transfer switch for switching between the aircraft power source and the external power supply, comprising a direct current

An external power supply for use in a no-break power transfer connection to an active aircraft power bus provided with power from an internal aircraft power source, and a power transfer switch for switching between the aircraft power source and the external power supply, comprising a direct current source of power, a transformer having at least one primary winding and at least one secondary winding, a switching circuit connected between the primary winding of said transformer and said direct current source for providing pulses of direct current to said transformer, which provides an alternating current output from its secondary winding, a frequency determining circuit having a predetermined nominal frequency output connected to control the operation of said switching circuit, means for sensing whether the output of said secondary winding of said transformer has a leading or lagging phase angle relative to the current on said aircraft power bus from the internal aircraft power source while both the output of said transformer and the aircraft power source are connected to the aircraft power bus, and control circuit means responsive to said sensing means detecting a lagging phase angle for increasing the nominal frequency of said frequency determining circuit until the output frequency of said transformer is in phase with the aircraft power bus, said control circuit means being responsive to said sensing means detecting a leading phase angle for decreasing the nominal frequency output of said frequency determining circuit until the output frequency of said transformer is in phase with the aircraft power bus during such time that both the external power supply and the aircraft power source are connected to the aircraft power bus.