# Improvement of Power Converters Performance by an Efficient Use of Dead Time Compensation Technique
## 3 Proposed Dead Time Compensation Technique
### Case 2: Dead-Time 1 \(\mu\)sec and Switching Frequency 1 kHz  
In case 2, the studies show that the current magnitude of the harmonics is the same, while the distortion factors are different due to time increasing as shown in Figure 13. If we take 1 micro-second, as shown in Figure 13, the third harmonic distortion without DTC is 16.26 percent. Moreover, after the implementation of the proposed DTC, method the distortion is reduced from 18.36% to 10.20%, as seen in Table 5. For the quality of power in industrial loads, an average increase of almost 8% is important.  
Figure 12: Without/with 10 \(\upmu\)s DTC (**a**) induction motor current (**b**) speed of induction motor (**c**) Torque pulsation.  
From Figure 13, the RMS of the fundamental current is equal to 100. Also, the RMS of the third harmonic current without DTC is 15.707 A and with DTC is 10.295 A. Therefore, \(IHD_{3}=29.2759/100*100=29.2759\%\) without DTC and \(IHD_{3}=14.645\%\) with DTC.  
Similarly, the fundamental voltage magnitude may be recovered in case 2 and the harmonics reduced as shown in Figure 14a. Figure 14a explicitly indicates the voltage magnitude in the presence of the DTC and also displays the same parameter before the DTC when time is 1 microsecond. It is clear that the voltage magnitude has dramatically changed as a result of the implementation of the new DTC methodology.  
In fact, the distortion of the phase angle in case 2 is also increased due to dead-time effects. However, if we take 1 micro-second, an effective DTC strategy will deal with this problem to some large extent. Figure 14b demonstrates the before and after the distorted phase angles of voltage magnitude  
Figure 14: With/without DTC (**a**) fundamental voltage (\(V_{a}\)) magnitude (**b**) fundamental voltage (\(V_{a}\) ) phase angle.  
Figure 13: Calculation of total harmonic distortion (THD) without and with DTC.  
\begin{table}
\begin{tabular}{c c c} \hline  & **Without DTC** & **With DTC 1 \(\mu\)s** \\ \hline Fundamental Frequency (50 Hz) & 8.227 & 6.714 \\ \hline Total harmonics distortion THD (\%) & 19.20\% & 16.16\% \\ \hline \end{tabular}
\end{table}
Table 5: FFT analysis of the load current.  
by using the DTC methodology, respectively. It is clear from this figure that the distortion of the phase angle was greatly decreased by the implementation of the new DTC strategy.  
In case 2 while the dead time is changed from 10 to 1 micro-seconds, the DTC incorporation in the inverter circuit is shown to reduce the total harmonic distortions and also torque pulsation as shown in Figure 15a. In addition, DTC will lead to realistic changes in an induction motor performance, along with the smooth operation, low noise, minimal torque ripples, and increased operating efficiency due to the lower harmonic losses. Figure 15a-c demonstrate the increase in current waveform quality, induction motor speed, and also torque pulsation, collectively.  
Figure 15: Without/with 1 \(\upmu\)s DTC (**a**) induction motor current (**b**) speed of induction motor (**c**) Torque pulsation.