# Special Issue \"Advances in Control of Power Electronic Converters\"
## 3 Control of DC-AC Converters  
The paper by [PERSON] et al. [5] studies the steady-behavior of a differential boost inverter used for generating a sinewave AC voltage from a DC source. The dynamics of the converter are analyzed using an accurate discrete time approach, adopting a quasi-static approximation and the Floquet theory. The undesired sub-harmonic oscillation exhibited by the inverter in some intervals is accurately predicted by means of the complement between analytical expressions and computational procedures. The study provides stability boundaries in terms of the proportional gain of the PI controller used to track the output voltage reference. The results contribute to the design of a boost inverter avoiding the consequences of the sub-harmonic oscillation in the quality of the input current and the output voltage. The proposed simulation results validate the theoretical predictions and the accuracy of the analysis.  
This contribution to the special issue [6] is focused on the same boost inverter as before. The objective is to reduce the voltage stress in power semiconductors by enforcing voltage references in the capacitor of the converters with a predefined harmonic content, which helps to decrease the voltage level required in each leg of the inverter for the entire cycle of the output voltage. Signal analysis allows definition that the voltage references with two harmonics is enough to achieve a considerable reduction of the voltage on the power semiconductors. To guarantee a proper tracking of the desired reference, two separate multiloop controllers were implemented, both using inner current control and outer voltage control. A complete linear modelling of the converter using the proposed control approach was derived from application of the equivalent control method. Moreover, qualitative analysis of the converter variables employing the harmonic balance method allowed them to derive a simplified plant model to facilitate voltage control design. The paper also compares the use of the proposed controller with the one developed in [7], showing how a small increase in complexity allows enforcement that minimum value of the capacitor voltages is close to the input voltage, then further reducing the voltage on semiconductors. A complete set of simulation results are provided for two electric standards (220 V/50 Hz and 120 V/60 Hz).  
[PERSON] et al. propose in their paper [8] a novel dead time compensation method for improving power quality and efficiency of inverters feeding induction motors. The method is developed considering a three phase IGBT bridge feeding the load through an output inductor. An idealized nonlinear model of the inverter is used to obtain theoretical expressions defining the effect of the dead time on the variables of the inverter. The converter is controlled using a constant frequency Pulse Width Modulator (PWM). The validity of the approach is confirmed by means of simulation results using a common V/f strategy for speed variation of two case studies. The results show that the proposed method reduces Total Harmonic Distortion (THD), increasing the quality of the output current.