Discrete-Time Super-Twisting Observer With Implicit Euler Method

This brief proposes a new discrete-time realization of the super-twisting algorithm based observer. While keeping the property of chattering suppression, the estimation precision of the proposed realization scheme is consistent with the continuous-time super-twisting algorithm (STA), that is, in the absence of noises, the estimation errors satisfy the standard asymptotical accuracy level, i.e., $|e_{1}| \sim \mu _{1}h^{2}$ and $|e_{2}|\sim \mu _{2}h$ with sampling time $h$ and two positive constants $\mu _{1}$ and $\mu _{2}$ . Comparing to the conventional explicit Euler method, the proposed scheme is more exact in the term of smaller constants $\mu _{1}$ and $\mu _{2}$ . The superiority of the proposed scheme is demonstrated through an example of typical buck converter circuit system.