On double Internal Model Control and its simulation for double-close-loop cascade speed drive system

Based on the non-linear characteristics of the thyristor cascade speed drive system, a double InternalModel Control (IMC) structure is proposed for double-close-loop cascade speed drive system. IMC is applied to the current & speed loop of Cascade speed drive system. With the help of “Engineering Design Method”, the “IMC Design Method” based on IMC principle is presented, the current & speed controllers are designed. The stucture of current controller & speed controller is PID, but the controllers have only one adjustable parameter that is directly related to systemperformance, the structure of controllers is simple. Theoretical analysis and simulation results show that the designed controllers based on IMC principle have better performance than the controllers designed based on “Engineering Design Method”.