Research Of SPWM Variable Frequency Power Based On DSP

Variable frequency power supply is a electronic devices that can bring AC power to another to some extent frequency and voltage adjustable sinusoidal AC power according with actual needs through a power converter (AC-DC-AC).This approach is what we used to say the indirect conversion. In the design, the inverter control system is the core and difficult of variable frequency power supply. With the development and improvement of operation speed of the digital signal processor, the some problems of the control system are gradually solved. Formed by the digital signal processing chip inverter control system, whether in the integration, immunity, flexibility, or in-line control, precision and other aspects reach the development unprecedented.The subject based on TI's 2000 series digital signal processors, in-depth study of filter circuit, rectifier, power factor correction circuit and inverter circuit. In the filter design, where adopt active power filtering technology (APF), which mainly uses command current operation and current tracking control link to achieve control in the DSP adjust. In the power factor correction, uses active power factor correction technique (APFC), DSP-based control for current tracking voltage waveform. Pulse width modulation is difficulties and focus in the inverter control system. This task in-depth study of several digital SPWM generation methods (including the tangent approximation sampling method and the secant approximation sampling method). And for each method were compared, finding the most optimal way. As the inverter design added a dead zone, subject also explained the dead zone effect in the modulation of is and further study several common methods of compensation of the dead zone.Then, proposed the hardware design according to the request. Mainly including sampling protection circuit, active filter circuit, inverter switching protection and buffer circuit, the Human-computer exchange platform based on LCD and matrix keyboard. Some of the main inverter is given software system design, including the A/D sampling subroutine, LCD, SPWM generation algorithm and so on.Finally, the subject based on the proposed design scheme above, in the Matlab and Simulink, we model the whole control system, gives the simulation waveforms, analyzed the simulation graph, verify the feasibility. Build a solid foundation for the follow-up research and design of the inverter.