Active Voltage Balancing Control of 9‐Level Multicell‐Based A‐NPC Inverters

ABSTRACT This paper presents an optimization‐free PWM control method for a single‐phase 9‐level flying‐capacitor (FC) multicell active neutral‐point‐clamped (A‐NPC) inverter. The controller measures the output current and the FC voltages and compares them to their references, then converts the comparison results into logic variables. These variables drive a set of logic equations that simultaneously (i) regulate each FC voltage to its target value and (ii) select the appropriate switching state to synthesize the requested multilevel output through PWM. Because the gating decisions are produced by direct logical evaluation—without cost functions, iterative search, or computationally heavy optimization—the method is fast and simple to implement. Experimental results verify reliable voltage balancing and proper operation during abrupt changes in DC‐link voltage, modulation index, and output frequency.