A novel real-time phase measurement method with recursive least square parameter estimation

Through observe three-phase voltage space rotation vector in the polar coordinate, the voltage space phase angle is divided into two parts, and which are fundamental wave phase angle and deviation Angle caused by the harmonic or unbalance component. And it introduces initial phase and angular frequency as parameters to establish observation equation. Taking the minimum period sum of squared errors as target function, adaptive memory length recursive least squares method is used to obtain real-time parameter estimation. The iterative process of the algorithm has no trigonometric calculations. It could be calculated simply and realized easily. The simulation results show that the algorithm is of good tracking performance for the grid voltage with harmonic and noise, in phase mutation, frequency mutation, voltage unbalance drop or all of them, and can satisfy the requirements of the power electronic conversion device real-time control.