Observability analysis for parallel multi-cell chopper

This paper deals with observability problems of the parallel multi-cell chopper. This type of choppers is a new DC/DC static power converter which has an output current equals to n times the source current where n is the number of cells. After recalling the dynamical equations of the converter, its hybrid dynamical behavior and properties are highlighted. This particular hybrid system induces new and difficult observability problems, such problem can be tackled by a new observability concept (The Z(T_N)-observability). Following this observability analysis an adequate sensor placement is proposed after an observability analysis and high order sliding mode observer designs are proposed. It is important to note that the use of physical extra sensors in order to measure the current in each phases increases the cost and the complexity of the system. That is why, its estimation by means of an observer becomes an attractive and economical solution. Our approaches are attested by several numerical simulations considering noisy measurements and load variations.