# Power Losses Investigation in Direct 3 \(\times\) 5 Matrix Converter Using MATLAB Simulink
## 5 Simulation Results  
### Simulation of Power Losses in IGBT-Based Bi-Switch with External Current Direction Detection Diode  
During the simulations, the constant gain of the virtual rectifier q\({}_{\text{RECT}}\) was maintained at its maximum value of 1. The gain of the virtual inverter was changed from 0.1 to its  
\begin{table}
\begin{tabular}{c c c} \hline \hline
**Part** & **Value** & **Unit** \\ \hline Inductor & 1.11 & mH \\ Inductor resistance & 160 & m\(\Omega\) \\ Capacitor & 7 & uF \\ Capacitor resistance & 7 & m\(\Omega\) \\ Damping resistor & 15 & \(\Omega\) \\ \hline \hline \end{tabular}
\end{table}
Table 2: Parameters of the input filter in the simulation.  
Figure 3: (**a**) Direct matrix converter, (**b**) Indirect matrix converter.  
maximum value of 1.6. The load for the matrix converter was represented with a five-phase RL circuit with values of R = 7.8 \(\Omega\) and L = 30 mH. The input power supply was simulated by three phase voltage sources with voltages set to 90 V RMS and frequency of 50 Hz. Three simulations were conducted with devices and parameters shown in Table 3.  
The simulation parameters of the devices used in the simulation from Table 3 were acquired from the datasheets of the mentioned parts. Direction diode and the MOSFET were also used in the experimental verification of the power losses. First, the simulation using IGBTs as components of the bidirectional switch was simulated. The results can be seen in Figure 4.  
As can be seen, most of the power losses were represented by the bidirectional switches. This is because current is always flowing through the IGBT/Diode pair, which can be seen in Figure 5.  
The upper subplot in Figure 5 shows power losses at the Q1, according to Figure 1. The current flowed from the Source to the Load according to the current direction. The  
Figure 4: Distribution of power losses.  
Figure 5: Instantaneous power losses in bidirectional switch.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Device** & **V\({}_{\text{CE}}\) [V] at 10 A** & **V\({}_{\text{F}}\) [V] at 10 A** & **R\({}_{\text{DSon}}\) [m\(\Omega\)] * \\ \hline IGBT STGW15H120 DF2 & 2.6 & - & - \\ Internal diode of IGBT & - & 3 & - \\ Direction Diode V20 PW15 & - & 0.9 & - \\ MOSFET NTBG080N120 SC1 & - & - & 110 \\ \hline \hline \end{tabular}
\end{table}
Table 3: Parameters of the semiconductors used in the simulations.  
power losses in Q1 were generated at the IGBT itself, and in Q2, the power losses were generated at the internal diode. The internal diode losses were higher due to the higher barrier voltage and higher internal resistance of the component. Similarly, when the current flowed from the Load to the Source, the losses were turned around, the losses in Q1 were generated in the diode, and losses in Q2 were generated by the IGBT itself. Other losses generated in the McC were in the current direction diodes as well as in the input filter. At the value of the q\({}_{\text{INV}}\) = 1.6, the bidirectional switches losses were 130 W, direction diodes losses were 16.8 W and input filter losses were 11.25 W. The total output power at the q\({}_{\text{INV}}\) = 1.6 was 860.78 W.  
Simulation of Power Losses in IGBT-Based Bi-Switch without External Current Direction Detection Diode  
However, the direction of the current in the IGBT-based bidirectional switch can be detected using one of the IGBTs, as described earlier, the model was redesigned, and the power losses without direction-detection diodes are shown in Figure 6.  
As can be seen, the power losses at higher output powers dropped significantly due to the absence of the detection diodes. The efficiency of both models is shown in Figure 7:  
The peak efficiency of the IGBT-based matrix converter with direction diodes was 84.1% at the output power of 860 W and the model without direction detection diodes reached an efficiency of 85.7% at the 874 W of output power.  
Figure 6: Distribution of power losses.  
Figure 7: Efficiency comparison of IGBT simulations.