Abstract
Due to the inherent double-frequency (2f0) ripple in single-stage single-phase photovoltaic (PV) grid-connected inverters, the maximum power point tracking (MPPT) will inevitably be affected. To improve the MPPT performances, a
passive LC power decoupling circuit with a robust second-order sliding mode control (SOSMC) is thus proposed in this paper. With the passive LC decoupling path, the double-frequency pulsation on the dc-link is effectively cancelled out. Thus, the MPPT accuracy is significantly enhanced and the utilization of a small dc-link capacitor becomes possible. However, resonance between the LC circuit and the main dc-link capacitor may appear, which can be damped through an active damping method. Additionally, the proposed SOSMC ensures good steady-state, dynamic performance (voltage fluctuation and settling time)
and the robustness of the dc-link voltage, which is also beneficial to MPPT control in terms of high accuracy and fast dynamics. The systematic design of SOSMC is presented and a detailed parameter optimization design of LC decoupling circuit is discussed. Experimental tests are performed on a 2.5-kW single-stage single-phase grid-connected inverter, and the results validate the effectiveness of the proposed strategy.
passive LC power decoupling circuit with a robust second-order sliding mode control (SOSMC) is thus proposed in this paper. With the passive LC decoupling path, the double-frequency pulsation on the dc-link is effectively cancelled out. Thus, the MPPT accuracy is significantly enhanced and the utilization of a small dc-link capacitor becomes possible. However, resonance between the LC circuit and the main dc-link capacitor may appear, which can be damped through an active damping method. Additionally, the proposed SOSMC ensures good steady-state, dynamic performance (voltage fluctuation and settling time)
and the robustness of the dc-link voltage, which is also beneficial to MPPT control in terms of high accuracy and fast dynamics. The systematic design of SOSMC is presented and a detailed parameter optimization design of LC decoupling circuit is discussed. Experimental tests are performed on a 2.5-kW single-stage single-phase grid-connected inverter, and the results validate the effectiveness of the proposed strategy.
Original language | English |
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Article number | 9079646 |
Journal | I E E E Transactions on Power Electronics |
Volume | 35 |
Issue number | 12 |
Pages (from-to) | 13000-13016 |
Number of pages | 17 |
ISSN | 0885-8993 |
DOIs | |
Publication status | Published - Dec 2020 |
Keywords
- Double-frequency ripple
- maximum power point tracking (MPPT) performance improvement
- parameter optimization design
- second-order sliding mode control (SOSMC)
- single-stage single-phase photovoltaic (PV) system