Multilevel converter systems and sinusoidal pulse width modulation methods

摘要

Sinusoidal pulse width modulation (SPWM) control techniques, computer readable mediums, and apparatus are presented for operating a multilevel converter, in which a desired AC node voltage level is determined through comparison of a plurality of carrier signals or values to at least one reference signal or value, and a switching state is selected from a plurality of redundant switching states corresponding to the desired AC node voltage level for generating switching control signals based at least partially on a switched capacitor voltage balancing goal or other control objective.

主权项

1. A power conversion system, comprising:
a multilevel converter including first and second DC nodes, an AC node, and a converter circuit including switching devices and a plurality of switched capacitors, the converter circuit operative according to a plurality of switching control signals to provide a plurality of distinct voltage levels at the AC node, the multilevel converter comprising:
a first circuit, including a first switching circuit with at least four switching devices connected in series with one another between first and second input nodes, with the AC node connecting two of the plurality of switching devices, and a clamping circuit including first and second clamping elements connected in series with one another between first and second internal nodes of the first switching circuit, and a third internal node joining the first and second clamping elements, anda switched capacitor circuit, including a plurality of capacitor switching devices individually connected between a corresponding DC node and a corresponding input node of the first switching circuit,the plurality of capacitors being individually connected between a corresponding input node of the first switching circuit and the third internal node; and a controller providing the switching control signals to the multilevel converter, the controller configured to compare a plurality of carrier signals or values to at least one reference signal or value to determine a desired AC node voltage level for operation of the multilevel converter, and to select from a plurality of redundant switching states for at least one of the distinct voltage levels at the AC node at least partially according to a control objective; wherein the controller provides the plurality of switching control signals to the plurality of switching devices of the first switching circuit and to the capacitor switching devices to provide the multilevel voltage at the AC node, the controller configured to select from among a plurality of redundant switching states for at least one of the distinct voltage levels at the AC node at least partially according to the desired AC node voltage level and the control objective.