Research on the Theoretical Steady-State Error of Direct Current Comparator

In virtue of modern control theory, combining with the analysis of structure and principle of direct current comparator (DCC), relative error formula of direct current ratio was derived to theoretically analyze the steady state value. Resolve each part of transfer function and then compound the closed-loop transfer function. Employ Nyquist stability criterion to judge the system stability; establish the closed-loop transfer characteristic simulation model; take unit ampere turn value as example and the simulation result was analyzed. The results showed that the secondary side fast tracked the primary side signal and output signal smoothly, without obvious transition appearance such as overshoot and oscillation, according with the principle of DCC. The steady-state error of direct current ratio is 2.5×10
⁻⁸
, consisting with the derived theoretical value, meeting the expected design requirements.