A Non-modular Matrix Structure for Component Count Waning in Multilevel Inversion

Recently the matrix structure has become an astute converter topology for ac–ac power conversion systems. The supersession of the conventional two stage, back-to-back voltage source converters by the matrix arrangement of bi-directional semiconductor switches has rendered the merits such as single stage conversion, elimination of bulky dc-link electrolytic capacitors, improved input side performance matrices, increased power density etc. The matrix structure can be treated as a versatile structure, which has a straddling scope in power conversion systems such as multiport converters and multi level voltage source inverters. Albeit the multilevel inverter (MLI) structure is under a diligent research, still the component count waning is the thrust area. This paper attempts to exploit the matrix structure to arrive at a reduced switch count MLI topology. The idea of the suggested modified matrix structure MLI (MMSMLI) is involving switches in columns and separate DC sources (SDCs) in the row links, through which the addition and subtraction amid the SDCs are made easy in the asymmetrical operation, and hence the creation of more output levels are possible. In addition the introduction of the cross switching in the matrix structure helps in curtailing the number of switching devices in the current conduction path at almost all output voltage levels. The feasibility and operation of the MMSMLI are exemplified in MATLAB R2017b software using the pertinent multicarrier pulse width modulation. Further the corroboration is done from a proof-of-concept laboratory scale prototype. The results emboldened the usage of the MMSMLI for traction applications and other space constrained low and medium voltage applications.