There are coupling effects between input and output variables of multivariable system of chemical processes. In control system design

diagonal dominance is usually implemented in transfer function matrix and then several single loop controllers are deployed. Since it is easy to define diagonal dominance by inversing transfer function

a pseudo diagonal dominance method was used to develop constant diagonal dominant compensation matrix for inverse transfer function. First

diagonal dominance was obtained by minimizing sum of module value squares of off-diagonal elements in each row of inverse open-loop transfer-function matrix at one or more frequency points. Then

inverse Nyquist array design method was adopted to design controller for the compensated system. Based on inverse Nyquist stability criterion

diagonal dominance degree was decided from dominance curve and Gershgorin diagram. Parameter range of feedback matrix was also selected from Gershgorin diagram. Dynamic compensators were designed according to method of single variable system

so that the system met quality requirements of dynamic controls. Finally

study on three examples show that the design method is simple and the control performance is excellent.