Low switching frequency predictive current control with dynamic model compensation for a 3-L inverter fed AC machine

Abstract

Three-level inverters offer several advantages, including reduced harmonic distortion in output currents and alleviated voltage stress on power electronic devices. However, the imbalance of the neutral point potential causes distortion in the output voltage if not considered during calculations. In the present paper, a model that incorporates the impact of neutral point imbalance on the output voltage is proposed, thereby enhancing the accuracy of current trajectory predictions. Additionally, the model features a dynamic compensation of the output voltage. To achieve a balance between neutral point potential symmetry and switching frequency, constraints are applied to limit the neutral point potential within a specific range. Simulation and experimental results underscore the effectiveness of the presented control scheme.

Appendix

$$ \left\{ {\begin{array}{l} {a_{2} (\tau_{0} ,k) = e_{d}^{\prime 2} + e_{q}^{\prime 2} } \\ {a_{1} (\tau_{0} ,k) = 2\left( {e_{d} e_{d}^{\prime } + e_{q} e_{q}^{\prime } } \right)} \\ {a_{0} (\tau_{0} ,k) = e_{d}^{2} + e_{q}^{2} } \\ \end{array} } \right. $$

(11)

$$ \left\{ {\begin{array}{l} {e_{d} = i_{sd}^{*} (\tau_{0} ) - i_{sq} (\tau_{0} )} \\ {e_{q} = i_{sq}^{*} (\tau_{0} ) - i_{sq} (\tau_{0} )} \\ \end{array} } \right. $$

(12)

$$ \left\{ {\begin{array}{l} {e_{d}^{\prime } = - \left. {\frac{{di_{sd} (\tau ,k)}}{d\tau }} \right|_{{\tau = \tau_{0} }} } \\ {e_{q}^{\prime } = - \left. {\frac{{di_{sq} (\tau ,k)}}{d\tau }} \right|_{{\tau = \tau_{0} }} } \\ \end{array} } \right. $$

(13)