**7. Conclusion**

66 MATLAB – A Fundamental Tool for Scientific Computing and Engineering Applications – Volume 1

u(2)

u(3)

u(2)

u(1)

u(1)

urt teta\_r F1 T1 control usr teta\_r F2 T2 control uts teta\_r F3 T3 control utr teta\_r F4 T4 control urs teta\_r F5 T5 control ust teta\_r F6 T6 control

1 F

(double) 1

F1


2 teta\_r

> S R

(boolean)

Q

1 urst

a) Control T block

Delay 1 (T control delay)

> 0.5 2 teta\_r

!Q >=

Delay 2 (Trigger pulse width)

(double)

b) T1 Control block

a) Simulation b) Experimental result

**Figure 21.** Control of thyristor T1

1 urt

**Figure 22.** Comparison of Simulation and Experimental Waveforms

This chapter has shown that it is possible to simulate many electrical power converters only using Simulink toolbox of Matlab, thus avoiding the purchase of expensive and complex dedicated software. The simulation method is based on the variable topology approach where switching conditions of semiconductor are realized by switching functions.

The first part of this chapter is dedicated to the modelling of linear loads: RL series, RLC series and L in series with RC parallel dipoles are considered. The second part deals with the simulation of DC-DC converters. The buck converter is first studied: after describing the operating phases, open-loop and closed-loop models are presented. A simulation is realised for closed-loop model showing good agreement with theoretical values. The third part shows how to model three-phases DC-AC converters. The electrical circuit and his complete Simulink model are presented and simulation results on RL series load with PWM control are shown. The fourth part presents the modelling of a six-pulse AC-DC converter which is frequently used in industrial applications. The complete model of this converter and his Simulink equivalent circuit are accurately described taking into account overlap phenomenon. A simulation result on RL series load is presented and compared to experimental result. The similarity of the two results shows the validity of the proposed model. The fifth part extends the method to controlled rectifier. The structure studied here is a six-pulse thyristor rectifier feeding a DC motor. The difference with the diode rectifier is presented with the introduction of a thyristor control block in the simulation. Simulations results are showed in continuous condition mode and are in good agreement with experimental results.

Many of the results presented in this chapter are computed with short simulation times (few seconds). This can be achieved thanks to the simplicity of the proposed method. The power electronics converters presented are used alone but the method can be easily extended to cascaded devices allowing the simulation of complex power electronic structures such as, for example, active filters with non-linear loads.
