In most industrial processes that use electrical energy as a source of tension or current, requiring a power circuit to control of these physical states.This paper deals with observability problems of the parallel multi-cell chopper. This type of choppers is a new DC/DC static power converter. After modeling of the power converter, its hybrid dynamical behavior and properties are highlighted. The observability properties of the state vector is studied from the new observability concept ( The Z(TN)- observability ). Following this observability analysis an adequate sensor placement is proposed after an observability analysis and a super-twisting observer has been proposed, that ensures finite-time convergence and robustness under bounded perturbations. That is why, its estimation by means of an observer becomes an attractive and economical solution. The suitability of the proposed strategy is proved by extensive computer aided simulations employing a comprehensive model of the system considering noisy measurements and load variations.