| After developing many years, analog controller is very nature, but it also has many disadvantages. With appearance and development of DSP, the digital control system has advantages of flexible control, high integration, strong anti-disturb ability, the realization of advanced control arithmetic and the convenience of real-time control. Digital control has been becoming one direction of modern power electronics development.First, three modes of SPWM modulation were introduced in the paper, including bi-polarity SPWM modulation, uni-polarity SPWM modulation and double-frequency uni-polarity SPWM modulation. After comparing, double-frequency uni-polarity SPWM modulation is used in the paper. After that, mathematics model is built. Second, it brings forward the flexible and compact design of hardware, including sampling circuit , driving circuit, protecting circuit and DSP system, and founds the hardware of inverter control system based DSP.Third, according to the traditional PI controller, several methods of PI controller realized by DSP is discussed. Increasing PI controller is selected. The total structure is offered in the software design.Finally, the experiment based on DSP show the feasibility of the system. The performance of the inverter can be improved by digital control.
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