Abstract
Voltage source inverters with output LC filter enable a sinusoidal output voltage with low harmonics, thus suitable for islanded ac microgrid or uninterruptible power supply applications. Conventional finite-set model predictive voltage control applies only a single switching vector per control period, leading to a variable switching frequency and significant output ripple. This paper resolves these issues by proposing an improved model predictive voltage control with optimal switching sequence (OSS-MPVC). First, an improved vector switching sequence is defined, aiming to reduce the output-voltage ripple with a constant switching frequency. Then, to tackle the difficulty in extending the OSS to high-order systems due to the coupling effect of the output filter, a generalized ‘one-step estimation’ solution is proposed, which directly associates the control-variable gradients with the vector switching sequence. To further enhance the output-voltage tracking accuracy, inter-sample dynamics are taken into account in the cost function. The control delay and dead-time compensation are also considered. Simulations and experimental results verify the feasibility of the proposed method.
Original language | English |
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Journal | IEEE Transactions on Power Electronics |
Volume | 36 |
Issue number | 3 |
Pages (from-to) | 3422 - 3436 |
ISSN | 0885-8993 |
DOIs | |
Publication status | Published - 2020 |
Keywords
- Microgrid
- Inverters
- Model predictive control
- Fxed switching frequency
- Optimal switching sequence