Discussion of power inverters under different control modes

Modulation theory is a powerful tool for power converter analysis. However, present modulation theory only provides limited equations and lack of flexibility for inverters under different control modes. Thus an extended modulation theory is proposed in the paper. The paper takes a three-phase six-pulse inverter as an example, and discusses in detail all the states of inverters under phase control and PWM control modes, and deduces complete modulation equations which are validated by simulation. The proposed equations can be used to deduce the voltage or current of arbitrary side from those of another side of an inverter under different control modes, and provide invaluable flexibility for the modeling and analysis of power inverters.