초록 ▼

A filter system for removing selected frequencies from AC power provided on at least two phase lines and a neutral line includes a phase-to-phase filter for removing a first selected AC component at a first frequency from the AC power wherein the frequency component has a line-to-phase displacement

A filter system for removing selected frequencies from AC power provided on at least two phase lines and a neutral line includes a phase-to-phase filter for removing a first selected AC component at a first frequency from the AC power wherein the frequency component has a line-to-phase displacement within first or second ranges. A phase-to-neutral filter is also provided for removing a second selected AC component at a second frequency different from the first frequency from the AC power wherein the second frequency component has a line-to-line phase displacement outside of the first and second ranges.

대표청구항 ▼

A filter system for a three-phase, four-wire AC power system having an AC source which develops polyphase AC input power, means coupled to the AC source for developing a neutral on a neutral line from the AC input power, a rectifier for rectifying the AC input power to produce DC power having a ripp

A filter system for a three-phase, four-wire AC power system having an AC source which develops polyphase AC input power, means coupled to the AC source for developing a neutral on a neutral line from the AC input power, a rectifier for rectifying the AC input power to produce DC power having a ripple component and an inverter having first and second inputs coupled to the rectifier for producing three-phase inverter AC power on three phase lines, comprising: a first filter comprising three impedances each connected between two phase lines such that the first filter is connected in a delta configuration, the three impedances attenuating a first component in the inverter AC power at a first selected frequency wherein the line-to-line phase displacement of the first component is within one of first and second ranges wherein the first range is between 90°and 150°and the second range is between 210°and 270°; a second filter comprising three impedances each connected between a phase line and the neutral line such taht the second filter is connected in a wye configuration, the three impedances attenuating a second component in the inverter AC power at a second selected frequency wherein the line-to-line phase displacement of the second component is outside the first and second ranges; and a DC filter coupled between the rectifier and the inverter wherein the DC filter includes first and second series-connected capacitors coupled across the first and second inputs of the inverter and wherein a junction between the capacitors is coupled to the neutral line.