An Improved Structure-Preserving Reduced-Order Interconnect Macromodeling for Large-Scale Equation Sets of Transient Interconnect Circuit Problems

The widely applied Structure-Preserving Reduced-order Interconnect Macromodeling (SPRIM) algorithm cannot retain the reciprocity or the block structure of the circuit matrices of the original system, being inherent to RCL circuits; and consequently it is harder to synthesize a Passive Reduced-order Interconnect Macromodeling Algorithms (PRIMA) model into a practical circuit. In order to overcome this deficiency, this paper proposes an improved SPRIM algorithm to maintain the structure features of the input-output correlation matrix. Firstly, the algorithm in this paper reorders the modified nodal analysis (MNA) equations. An Input-Output structure Preserving Order Reduction (IOPOR) technique applicable to SPRIM is then proposed. Also, one combines the IOPOR technique with the conventional SPRIM algorithm to obtain a new projection matrix that can maintain the input and output correlation matrix of the original system. The feasibility and effectiveness of the proposed algorithm are verified through numerical analysis and calculation of typical problems.