Design method of multivariable PI controller for turboprop engine based on equivalent transfer function

Traditional centralized Proportional Integral (PI) controller design methods based on Equivalent Transfer Functions (ETFs) have poor decoupling effect in turboprop engines. In this paper, a centralized PI design method based on dynamic imaginary matrix and equivalent transfer function is proposed. Firstly, a method for solving equivalent transfer functions based on the dynamic imaginary matrix is proposed, which adopts dynamic imaginary matrix to describe the dynamic characteristics of the system, and obtains the equivalent transfer function based on the dynamic imaginary matrix characteristics. Secondly, for the equivalent transfer function, a centralized PI control gain is designed using the Taylor expansion method. Meanwhile, this paper further proves that the centralized PI design method proposed in this paper has integral stability. Considering the impact of altitude and Mach number on turboprop engines, a linear feedforward control method based on the transfer function matrix is further proposed based on the centralized PI controller, and the stability of the entire comprehensive control method is proved. Finally, to ensure the safe and effective operation of the turboprop engine, a temperature and torque limiting protection controller is designed for the turboprop engine. Simulation results show that the centralized PI controller design method and linear feedforward control method proposed can effectively improve the control quality of turboprop engine control systems.