Robustness of Model-Predictive and Passivity-Based Control in the Three-Phase DC/AC Converter Application

In modern controller design, various solutions for controlling power converter systems
can be found depending on their applications, speed of working, pulse width modulation (PWM)
techniques, switching frequencies— fc, and different load types. The need to manipulate control
parameters can be often observed in classical structures, e.g., well-known PID, repetitive, or deadbeat
control particularly sensitive to distinct parameters uncertainties. The purpose of this paper is to
present an improved version of controllers designated for a UPS that will be considerably resistant to
model changes. Proposed control techniques are independent of unexpected output filter changes:
Lf —filter coil inductance and Cf —filter capacitor conductance. The second aspect of this paper is
to compare effectiveness of modified predictive MPC (model-predictive control) and feedback PBC
(passivity-based control) controllers in reducing output voltage total harmonic distortion (THD) for
various load values. The biggest distortions of output voltage were observed during experiments
with nonlinear RC load. Both simulation and experimental verification of mismatching parameters
were performed and examined. Thanks to the proposed solution, the output voltage THDv quality
factor was reduced below 8% in an efficient way for all the applied loads and stayed at the level of
1% when well-matched filter parameters were provided.