Research Of Wind Power Converter In Parallel Control System Based On EtherCAT

Energy and environmental issues are major problems of human need to confront and resolve. Clean, renewable energy will inevitably become an important part of the future energy structure. Wind energy as a clean and renewable energy is bound to become a strong proponent of the country and development focus. From the current trend of wind power technology development, the growing capacity of the generator set makes single grid inverters far from satisfactory. If using bigger power rating of power devices, costly will be great. Therefore, the converter system parallel operation will become increasingly important.Parallel converter technology can effectively increase the system capacity, but at the same real-time data transmission and reliability requirements between each converter are also corresponding increased. In the traditional CAN communication or RS485 communication, the transfer rate is slower and less reliable, which leading to the converter module signal synchronization between the parallel converters is poor. It is difficult to meet the requirements of the parallel converters. To solve this problem, this paper introduces EtherCAT real-time Ethernet technology, and proposes a control scheme based on EtherCAT bus technology. Because EtherCAT technology provides precise clock synchronization, which ensure the consistency of each converter station signal transmission, so wind power converters can meet the requirements to run in parallel.This article introduced the working principle and distribution clock function of the EtherCAT technology. This scheme selects the CX2030 PLC from Beckhoff as the master controller. The converter slaver equipment is developed based on EtherCAT slaver interface controller ET1100 and TMS320F28335 DSP chip. A EtherCAT network structure with one master and multiple slavers is built, and a hardware and software design of the control system is provided. Finally, a back-to-back experimental platform was built. It consists of four sets of 500KW three-level converter connected in parallel. Then CAN communication solution and proposed EtherCAT solution were tested on the platform. Experimental results show that, the proposed EtherCAT solution is reasonable and practicable. And the differential-mode circulating current between the converter is much smaller compared to CAN communication solutions.