Patent ID: 8976556
Filing Date: 2015-03-10
Classification: H02M

Abstract:
1. A method for space vector modulation of a multilevel inverter based on a space vector diagram of switching states of the inverter, wherein each switching state defines a combination of phases, wherein the space vector diagram includes a hexagon having a size proportional to a level of the inverter, the hexagon includes a set of vertices uniformly spaced to partition the hexagon into a set of modulation triangles, wherein sides of each modulation triangle are formed by vertex vectors connecting corresponding vertices, wherein the switching states of adjacent vertices are different by a unit value of the phase determined by an angle of the vertex vector connecting the adjacent vertices, the method comprising: representing a reference vector as a sum of a remainder vector and a set of vertex vectors connecting a center vertex of the hexagon with a first vertex of the modulation triangle enclosing the reference vector, wherein the remainder vector connects the first vertex with the reference vector; modifying iteratively, for each vertex vector in the set, starting from a current switching state of the inverter at the center vertex, a corresponding phase of the current switching state to produce a first switching state of the inverter at the first vertex, wherein, for each iteration, a type of the modification and the corresponding phase is determined based on a function of the angle of the corresponding vertex vector, and the corresponding phase is increased or decreased by the unit value based on the type of the modification; determining a second switching state of the inverter at a second vertex of the modulation triangle and a third switching state of the inverter at a third vertex of the modulation triangle based on an angle of the remainder vector; and modulating the inverter based on the first, the second, and the third switching states.