The Research And Design Of Control System For A New Type Of DC Transmission System Based On DSP And FPGA

The network interconnection of the whole country is an inexorable trend with the development of Chinese electrical network. Building "Transmission electrical power from West to East" and "Exchange electrical power between South and North" projects is the desirability for the unbalanced resources distribution and the unbalanced demands. It is also a requisite strategy of our power industry. UHV power grid will be the major development of SGCC, and DC transmission, which fits for transmitting electrical power in long distance and large capacity and will be widely used in UHV engineering. Converter transformer is one of the most important equipments in HVDC transmission system. The auto-compensator and harmonics suppression converter transformer has Independent intellectual property rights of china and many merits that traditional transformer doesn't. The control system of new type DC transmission system adopting novel transformer and its filter device are mainly studied and designed in this thesis.The development survey and technical characteristic about DC transmission is summed up in this thesis. And the control principle, methods, tactics and characteristic of DC transmission system are introduced. Compared with the traditional system, the structure, characteristic and advantage of the new type DC transmission system adopting novel transformer and its filter device are analyzed and the theory on its filter device and reactive power compensator for the new system are dissertated. Based on the above, the whole structure, function frame and control tactics of the control system for new type DC transmission are presented and the working principle is explained.Based on DSP (Digital signal processor) and FPGA (Field Programmable Gate Array), the control system is designed for the new type DC transmission system. The hardware design includes the main circuit, the control circuit of DSP, the input channels, the output channels, anti-jamming circuit and so on. And the software design includes AD sampling module, the signal processing module, the adjusting control module, the adjusting module of PI, the synchronous frequency multiplication and so on. The synchronous frequency multiplication is based on a new total DPLL (Digital Phase-Locked Loop). The new total DPLL device is designed and simulated in QUARTUSâ…¡environment based on FPGA. The simulative and experimental results prove that the new total DPLL has many advantages, such as the rapidness of frequency tracking, high precision of frequency multiplication and the low error. And it has good value of application. By using PSCAD/EMTDC, a tool for electromagnetic transient simulation, a simulation model of novel DC transmission system adopting novel transformer and its filter device is established and the simulation result proves the correctness and rationality of the control tactic.