A Sliding-Mode Controlled Single-Phase Grid-Connected Quasi-Z-Source NPC Inverter With Double-Line Frequency Ripple Suppression
In this paper, double-line frequency (2ω) ripple suppression and SMC with time-invariant (fixed) switching frequency methods are proposed for single-phase grid-connected three-level neutral-pointclamped quasi-Z-source inverters. The 2ω ripple suppression method is based on the 180° phase difference existing between the 2ω ripple components of the capacitor and inductor voltages in the dc-side. Hence, when these components are added in the closed-loop, a phase cancellation occurs so that the inductor current reference can be generated without 2ω ripple component. In this case, the actual inductor current, which is forced to track its reference, has no 2ω ripple component. In addition, the grid current control is achieved via sliding mode control (SMC). Unlike the existing SMC methods, the proposed SMC achieves fixed switching frequency which is made possible by eliminating the discontinuities in the sliding surface function using a boundary layer. The proposed ripple suppression method together with the SMC method offers many advantages such as fast dynamic response, zero grid current error, simple implementation, robustness to parameter variations and fixed switching frequency. The effectiveness of the proposed control method is verified experimentally under steady-state and transient conditions.
Other Information
Published in: IEEE Access
License: https://creativecommons.org/licenses/by/4.0/
See article on publisher's website: https://dx.doi.org/10.1109/access.2019.2949356
Funding
Open Access funding provided by the Qatar National Library.
History
Language
- English
Publisher
IEEEPublication Year
- 2019
License statement
This Item is licensed under the Creative Commons Attribution 4.0 International License.Institution affiliated with
- Hamad Bin Khalifa University
- Qatar Environment and Energy Research Institute - HBKU