Selective Harmonic Mitigation: Limitations of Classical Control Strategies and Benefits of Model Predictive Control

Abstract

Selective harmonic mitigation pulsewidth modulation (SHMPWM) is a very interesting modulation technique as an alternative to carrier-based PWM. It allows to comply with grid codes that limit current and voltage harmonics in high power applications, where the switching frequency is limited to reduce switching losses. However, designing a PI-based closed-loop control with this modulation is not straightforward and has some challenges regarding the dynamic response. This paper analyzes the limitations of classical control strategies when combined with SHMPWM and studies the potential benefits of model predictive control (MPC) as an alternative. MPC has emerged as a promising approach to overcome the problems of the former control since it complies with harmonic limits while improving the dynamic performance of the converter.