New Induction Motor Synchronous Angular Frequency Estimation Method Based on Dual Second Order Generalized Integrator-frequency Locked Loop

In order to solve the dc drift and the initial value problems of the pure integrator in the voltage-model-based flux observer, the low-pass filter(LPF) is often used. However, the LPF may produce magnitude error and phase error in the estimated flux. Thus, a compensation block is often used to eliminate these errors. The performance of the LPF-based flux estimation method often highly depends on the accuracy of the synchronous angular frequency. We recently presented a new synchronous angular frequency estimation method based on second-order generalized integrator frequency-locked loop. However, the dynamic performance of this method is not very satisfactory. This paper presents a detailed theoretical analysis on the dynamic errors of this method. Further, an improved method based on dual second-order generalized integrator frequency-locked loop is presented. The properties and performance of the new synchronous angular frequency estimation method are analyzed in comparison to the former one, demonstrating that it has improved dynamic response. An induction motor speed control system is built based on the vector control and controlled by TMS320F2812 DSP. Simulation and experimental results prove the effectiveness of the proposed method.