Output Voltage Effects in a 2x2 SMC Caused by Time Index Change

A Stacked Multicell Converter (SMC) is an inverter specially adapted to high voltage applications. This inverter is composed by commutation cells ordered in p rows and n stacks, reducing semiconductors commutation stresses and high operation frequencies can be reached [2, 3]. This structure requires 2(pxn) switches to generate an output signal similar to a sinusoidal waveform. However, the switches must be correctly controlled. The most commonly used control technique has been the typical PWM [1, 4, 5]. However, it is possible to generate a control scheme by FPGA technology. So, the control signals are established by the designer. This kind of control has been called Patron Control Signals [6]. In this paper, a complete mathematical analysis to the output voltage behavior for a 2x2 SMC, when the time index (β) changes, is presented. In addition, simulations results are shown to validate the mathematical analysis.