Research On Optical Fiber Triggering And Control System Design Of High-Voltage Soft Starter

In the developed industrialized countries, three-phase induction motors consume about 70% of the electric power. Motor starting directly is a big shock on the grid and its own, consuming too much electric power. Therefore, the implementation of effective control of induction motors to ensure motor's energy-saving starting, to avoid the electrical impact on the power grid, so that its safe and economic operation of great importance. Soft starter with its smooth starting performance, small impact of current, non-contact, energy saving and other advantages, has been widely used in the field of electric drive. In China, the thyristor-based solid state soft starter in the low voltage (eg, 380V) motor areas has been applied widely. But for the high-voltage series, due to technical reasons, most of it is imported from abroad. So the thesis designs a kind of high-voltage motor's soft starter based on thyristor.Firstly, this paper introduces the domestic and international developments of thyristor-based soft-start technology, analyzes theoretically on the soft-start motor control principle, and simulates a MATLAB model of the soft-start system under the torque control starting mode to prove its superiority.Then on the base of analysis and compare of the way to enhance the voltage degree of soft-start device and the principle of three common thyristor triggering system, it brings forward a new way to solve the voltage balancing of the series connection of thyristors, which is the technology of indirect optical fiber signal trigger. In addition, it gives an expatiation of the soft starter, including the operation principle, the main circuit design and the design of its driver circuit and auxiliary power circuit.In hardware design, it designs the low voltage control system using the sixteen core microcontroller MC9S12XS128, including the main control circuit and the PWM drive and isolation circuit, current and voltage signal sampling and conditioning circuitry, synchronization signal detection circuit, LCD12864 liquid crystal display and keyboard input circuit. In software design, it focuses on the incremental PID algorithm programming of the torque control starting mode. Finally, it explains in detail the Freescale Code Warrior IED online development environment, using the BDM debugging method and the host computer data exchange testing method, and carries out effective experiments to verify the correctness of the control circuit and the control validity of said high-voltage soft starter.