A Novel Approach for Comprehensive State-space Modeling of the Multilevel Grid Connected Inverters

Subject Areas : Renewable energy

Hassan Manafi Miralilu ¹ , Mahdi Salimi ² , Jafar Soltani ³ , Adel Akbarimajd ⁴

1 - Department of Electrical Engineering- Ardabil Branch, Islamic Azad University, Ardabil, Iran
2 - Department of Electrical Engineering- Ardabil Branch, Islamic Azad University, Ardabil, Iran
3 - Department of Electrical and Computer Engineering- Isfahan University of Technology, Isfahan, Iran
4 - Department of Engineering- University of Mohaghegh Ardabili, Ardabil, Iran

Received: 2021-08-30 Accepted : 2021-11-02 Published : 2021-12-22

Keywords: nonlinear controller, state-space modeling, cascaded multilevel inverter, H-bridge converter,

Abstract :

In this paper, a novel approach for comprehensive state-space modelling of the grid connected multi-level inverters is proposed. Details of the developed method is presented using cascaded H-bridge converters, however it can be applied to other topologies of the grid connected inverters as well. In multi-level converters, due to their nonlinear characteristic, application of the nonlinear controllers is more beneficial to ensure stability of the system in a wide range of operation. Hence, the state-space model is required to design a nonlinear controller. To achieve converter model, it is divided into some sub-circuits considering different operational intervals in a switching cycle. To verify accuracy and effectiveness of the obtained state-space model, a laboratory setup of a multi-level. Converter with two H-bridges has been designed and implemented. Also, results of the developed state-space model has been compared with the simulation/experimental results of the grid-connected converter.  According to the simulation and experimental result, accuracy of the model is verified. It should be noted that all of the simulations have been performed by EMTDC/PSCAD toolbox.

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