A Study On Controller For High Voltage Frequency Converter Based On DSP

It is very important for China to develop high voltage and power frequency control systems for the sake of energy savings and industry control. In recent years, the multi-levels topology structure has become an important tendency and has been widely applied in the high voltage and high power drive fields. Based on the series cell multi-levels topology structure, the thesis took the controller for the high voltage frequency variable device as the study object to complete the hardware and software design for the controller, by which the real time computation of the SPWM pulse width and the controlling of the speed variation was achieved, and the safe, stable running of frequency control system was guaranteed.In this thesis, several main topologies of multi-level inverter were compared, and their respective advantages and disadvantages were analyzed carefully. On the basis of series cell multi-level topology structure, several sampling methods and modulating methods were analyzed and compared by simulations, and finally the method of regulated sampling and the method of carrier level phase-shift modulating were determined. The simulation of series cell multi-level topology structure under the carrier level phase-shift modulating and synchronous carrier phase shifting modulating by MATLAB was completed, and the results verified the feasibility and superiority and applicability of the carrier level phase-shift modulation strategy.The compositions of series cell multi-level high voltage inverter system were introduced, and the software design and hardware circuit design of the controller were completed. For the hardware design, the DSP- and CPLD-directed controller for inverting control system was made, in which the hardware circuit design of DSP central control board and expansion board was included. For the software design, the design ideas were introduced, and the design of sequence control and V/f speeding control was elaborated. The algorithm of pulse width, the realizing flow of the program and the distributing principals of pulse signals were presented. The application of carrier phase shift control SPWM modulating in series cell multi-level high voltage inverter system was achieved.Finally, the developed controller for the high voltage frequency variable device was tested in the testing platform. The output of the testing verified that the modulating method of carrier level phase-shift SPWM was realized successfully.