Analysis of instability in feedforward loop

Although the feedforward system is theoretically unconditionally stable, there are circumstances under which oscillation can occur. These oscillations are possible in both the error-determining loop and the error-cancellation loop and may occur in-band or out-of-band depending upon the parameters of the design. The authors analyse the circumstances under which oscillation is possible, and highlight the corrective action which may be taken in order to eliminate the possibility of its occurrence