Performance analysis and comparison of phase angle estimation schemes for four-quadrant converters of high speed train

Accurate and fast grid voltage detection is critical for four quadrant converters of high speed train. The weighted least-square estimation method (WLSE) is used in this paper. This method is able to measure instantaneously the fundamental component, the phase angle and the frequency of the line voltage without a significant delay (in a few sampling periods). Three schemes of phase angle estimation including zero crossing detector, PLL and WLSE are analyzed and compared in detail. The simulations and experiment show that WLSE has the best performance under distorted and transient grid conditions.