State estimation of variable frequency power grid of multi-electric aircraft based on adaptive enhanced complex-coefficient filter

The power grid of a multi-electric aircraft is a typical isolated island microgrid with a wide frequency range from 360 to 800 Hz. The dynamic performance of the traditional constant-frequency power grid synchronization method is insufficient in the variable frequency power grid of the multi-electric aircraft. An adaptive enhanced complex-coefficient filter-based phase locked loop (AECCF-PLL) is designed for the variable frequency power grid by integrating an adaptive module into the enhanced complex-coefficient filter-based phase locked loop to accurately estimate the state of variable frequency power grid. The relationship between the transfer function and the step response is analyzed. The relationship between the model parameters and the frequency is derived, and the frequency adaptive module is established to meet the requirements for stability and rapidity in the state estimation of the variable frequency power grid. The experimental results show that the proposed AECCF-PLL can achieve the rapid and stable estimation of the state of the variable frequency power grid when there are disturbances such as large or small frequency jumps, harmonics and slopes.