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Multilevel Multiphase Space-Vector PWM

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This example shows the operation of the multilevel multiphase SVPWM and two-level multiphase SVPWM.

Oscar Lopez, Jacobo Alvarez, Jesus Doval-Gandoy and Francisco Freijedo, Electronics Technology Department University of Vigo, Spain. olopez@uvigo.es

Description

This example shows the operation of the Multilevel multiphase SVPWM and Two-level multiphase SVPWM. It includes a five-level five-phase inverter feeding a passive load. Detailed information about the modulation algorithm, its Simulink® implementation, and the simulated case can be found in [1].

1. The 'Sine Wave f' and 'Fifth harmonic' blocks generate an unbalanced five-phase reference voltage with a fifth harmonic.

2. The 'Normalize' block normalize the reference voltage

3. The 'Multilevel multiphase SVPWM' performs the multilevel multiphase space-vector PWM (SVPWM) algorithm presented in [1]. This block makes use of the block 'Two-level multiphase SVPWM', also described in [1], that can be used alone with two-level multiphase converters. Both blocks require the specification of the number of phases and their outputs are a matrix with the switching vector sequence and a vector with the switching times.

4. The 'Sequence' block provides the time sequence of switching vectors.

5. The 'Trigger signals' generates the proper trigger signals from output levels specified in each switching vector.

6. The '5-level 5-phase cascaded full-bridge inverter' block is the ideal model of the multilevel voltage-source converter.

7. The loads are resistances with a series connected inductances. Load neutral is connected to the inverter neutral.

Simulation

The following signals can be observed:

'Vref' is the sampled voltage reference for each phase.

'filtered Vout' is the output voltage of 'Vout' phase after been filtered with a low-pass filter.

'Vout(k)' is the switched output voltage of phase 'k'. The phase shown in the scope can be selected by means of the 'Phase selection' block.

The filtered output voltage 'filtered Vout' of the converter follows the reference voltage 'Vref'. Therefore, the modulation is working properly.

The output voltage of the inverter 'Vout' has five levels in phases b, c, and d (k=2,3,4) and three levels in phase a and e (k=1,5).

References

[1] Oscar Lopez, Jacobo Alvarez, Jesus Doval-Gandoy and Francisco D. Freijedo "Multilevel Multiphase Space Vector PWM algorithm", IEEE® Transactions on Industrial Electronics, vol. 55, no. 5, pp. 1933-1942, May 2008, doi:10.1109/TIE.2008.918466.