Open AccessResearch on the smart modular cascaded solid state transformer interfaced to distributed photovoltaic power generation system
Author(s) -
Zhao Hengyang,
Zhu Taiyun,
Cheng Dengfeng,
Li Binbin,
Ding Jinjin,
Li Yuanzhi
Publication year - 2017
Publication title -
the journal of engineering
Language(s) - English
Resource type - Journals
ISSN - 2051-3305
DOI - 10.1049/joe.2017.0656
Subject(s) - modular design , converters , photovoltaic system , transformer , rectifier (neural networks) , computer science , feed forward , electronic engineering , power electronics , electrical engineering , voltage , engineering , control engineering , operating system , stochastic neural network , machine learning , recurrent neural network , artificial neural network
Distributed photovoltaic (PV) power generation system has recently gotten more and more attention in renewable energy fields. Solid state transformer (SST) is a kind of power electronics equipment which utilises power electronics technology to achieve voltage conversion. This paper adopts a topology of single‐phase smart modular cascaded SST which consists of three stages, cascaded modular rectifier stage, the dual active bridge (DAB) converter stage, and the single‐phase full‐bridge inverter stage. The output‐paralleled DAB converters offer a DC‐bus port. This study proposes an improving MPPT method for the PV cells which directly connect to the DC‐bus port. Rectifier stage adopts a single‐phase d – q vector‐based common‐duty‐radio controller aiming at balancing each modular current, DAB stage utilizes a voltage feedforward and feedback‐based controller to regulate each modular voltage. The DC‐bus voltage could be regulated to track MPP of PV cells. Compared to conventional control strategy, the improving one simplifies the circuit structure, reduces the controlled variables, provides the possibility of increasing the number of cascaded modules, and makes it easier to access to distribution network. Simulation results are presented to proving the proposed control strategy. In addition, a 6kW experimental prototype is built to validate the effectiveness.