METHOD FOR DETECTING PHASE ANGLE AND INVERTER

摘要

PROBLEM TO BE SOLVED: To provide a method for detecting the phase angle of a three-phase AC voltage or current in which the phase angle can be detected precisely even if noise is included in the detection waveform of voltage or current, and to provide an inverter comprising a phase angle detection means by the method and a control means.

SOLUTION: Instantaneous value of a three-phase AC voltage or current is detected every sampling period, an orthogonal biaxial component of α-axis component and β-axis component is operated from the instantaneous value thus detected. Instantaneous value θ of phase angle is then operated from the α-axis component and the β-axis component by operating θ=arctan(β/α). Prediction value θp of phase angle is operated from the instantaneous value data of a plurality of latest phase angles by straight line approximation such as least square approximation.

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