Complementary half controlled three phase PWM boost rectifier for multi-DC-link applications

The half controlled three phase pulse width modulated (HC3ΦPWM) boost rectifier has simpler and more robust structure compared to the full controlled three phase (FC3Φ) PWM boost rectifier, and better performance compared to the diode rectifier. One of the main drawbacks is its even harmonic input current distortion which may cause undesirable resonance problems. Other issues of concern are fairly large AC side inductance and the necessity of intentional lagging power factor current command to obtain reasonably low input current THD. This paper describes methods with which these problems can be handled for a certain type of application by introducing complementary topologies of HC3ΦPWM boost rectifiers. Two types of complementary configuration, rectifier leg complementary and input transformer complementary, are introduced. The former comprises an emitter common and a collector common HC3ΦPWM boost rectifiers. The latter utilizes complementary polarity of the input transformer secondary windings. Two control schemes for this rectifier are presented: (a) independent local control (ILC), and (b) coordinated central control (CCC). ILC can lead to even harmonics cancellation with equally supplied loads by two DC links. CCC can reduce not only even harmonics but also nontriplen odd harmonics (5th, 7th, ...). In CCC, AC side inductor size can be reduced and no lagging power factor current command is necessary. In addition, CCC can handle load imbalance between two DC links to a certain extent. Power stage description, control principles, simulation results and experimental results are presented