The Research And Application Of PWM Recitifer In Excitation Control Systems Based On DSP

Excitation controller is an important component of generator. It has a direct impact on the operation of generators, on power systems safe and stable operation .With the development of power electronics technology and the continuous improvement of power semiconductor switching device and control chip, performance of excitation controll get rapidly develop, rectifier of excitation controller change from the traditional thyristor to PWM controll, PWM rectifier will make current of drift-net side become sinusoid and make power factor up to one ,reducing the network side and the rectifier side harmonic pollution, the system improves the quality of electricity supply and reduces the damage of synchronous generator stator and rotor due to additional temperature.Rectifiers used in excitation control system have high value, this article mainly focus on hardware design and software algorithm of PWM rectifier , it as follows:Using Intelligent Power Module (IPM) to replace the traditional thyristor as a power switching device, it is used to construct PWM switching power rectifier circuit. Because this IPM integrated with six IGBT, IGBT drive and protection circuits, the design mainly concentrated in: IPM power design, IPM and DSP interface circuit design, IPM external protection circuit design, it improved power switching circuit reliability.Using AC sampling to replace the traditional ways of DC sampling. PWM rectifier needs various voltage and current signal conditioning, conditioning makes the signal directly connect to control module pin-AD of the digital signal processor (DSP), the specific design of the signal conditioning circuit include: AC voltage signal conditioning, AC current signal conditioning, DC voltage signal conditioning, frequency of AC voltage signal conditioning circuit design,it reduces the cost of the sampling areas.Using TMS320F2812,which is 32-bit fixed point DSP core ,as a control chip.Using the on-chip DSP resources program AD signal sampling algorithm, frequency measurement algorithm, SPWM algorithm (used to build three-phase inverter power supply), as well as SVPWM algorithm (for the PWM Rectifier network side's power factor).In this paper, hardware and software design provide a reference for building the ultimate PWM rectifier and laid the foundation for a new type of excitation control system construction.