Experimental validation of nonlinear and adaptive control strategies implemented on a 3-phase 3-level NPC boost rectifier

In this paper, the authors present detailed experimental validation of nonlinear and adaptive control strategies implemented on a 3-phase 3-level neutral point clamped (NPC) boost rectifier. These control strategies are developed to control power factor, output and neutral point voltages and also to reduce parametric variation and utility disturbance influences. These two control methods are designed and applied to the converter via a 1.8 kHz pulse width modulator. They are executed in real time using the MPC8240 MOTOROLA microprocessor. The experimental results, obtained on a 1.2 kW laboratory prototype, illustrate the performance of these two methods. The nonlinear controllers are characterised by reduced complexity and quite good performance in comparison to linear control method. The adaptive control exhibits much better performance in a wide operation range for parametric variations, utility disturbances and also for output voltage regulation.