SYSTEM AND METHOD TO EXTEND SYNCHRONOUS OPERATION OF AN ACTIVE CONVERTER IN A VARIABLE SPEED DRIVE

    公开(公告)号:WO2008092154A3

    公开(公告)日:2008-07-31

    申请号:PCT/US2008/052211

    申请日:2008-01-28

    Abstract: Systems and methods for synchronous operation of variable speed drives having active converters include extending the synchronous operation of an active converter to the AC mains voltage during complete line dropout. A phase angle control circuit includes a squaring amplifier, a first phase-lock loop circuit associated and a second phase-lock loop circuit. The squaring amplifier receives the AC power source and outputs a rectangular output signal to a pair of phase lock loop (PLL) circuits. The first PLL circuit with a first lag-lead filter is configured with a high cutoff frequency to provide the converter stage with a phase angle parameter; and the second phase-lock loop circuit including a second lag-lead filter configured to have a low cutoff frequency to provide the lag-lead filter the capability of storing the phase angle of the mains voltage during mains interruption.

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