Two-sided projection method in variational equation model order reduction of nonlinear circuits

For relatively strong nonlinear circuits, the conventional variational order reduction method loses efficiency due to the exponentially increased number of inputs and the one-sided projection technique. In this paper, we propose a two-sided projection approach which is capable of matching a much higher number of moments than the one-sided projection method. We show by theoretical analysis and experiments that the two-sided projection method is very efficient for the variational equation model order reduction of nonlinear circuits.