| With the development of new energy sources and hybrid energy systems,multi-port converter is essential in the near future.The combined multi-port converter with common DC bus shows its huge application prospects thanks to it is flexibility of operation and easy expansion.Its control requirements mainly include the bottom-level control and the top-level control.The bottom-level control is the individual control of each port,including constant voltage control,constant current control,etc.The top-level control is the unified control of the entire system,including the maximum power point tracking of the photovoltaic cell,etc.The commonly used master-slave control method is only suitable for large-scale multi-port systems because of the high hardware cost.And there is a certain delay due to the communication between the controllers.For low-power multi-port converter systems,using a single controller to control is a better solution.However,it is faced with many challenges,such as insufficient computing time and allocation of controller resources,etc.This article focuses on how to realize the control of the combined multi-port converter with a low-cost controller.Firstly,a multi-port converter topology suitable for typical household photovoltaic systems is introduced.Then,through analyzing functional requirements and performance requirements,the control objectives of the topology are summarized.Based on that,the bottom-level and top-level control strategies of each port are designed in the order of load port and power supply port.After this,in order to realize the control strategy designed above in a controller,an appropriate digital signal processor is selected as the controller and its computing resources are reasonably planned.Finally,experiments are conducted under the existing conditions,and the experimental results proved that the control strategy design and the planning of the controller’s computing resources in this paper are correct and effective. |
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