Research On The DSP Based Controller For Frequency-variable High Voltage Device

As the new typed power electronic's devices continue to appear and the continuing development of the digital controlling technique, the high performanced asynchronious speed variable system has been used in many industrial fields. Recently, the multi-levels topology structure has became an important tendency in high voltage frequency-variation field. The controller for the high voltage frequency variable device is the kernal of the high voltage frequency variable speed adjusting system, this topic takes the controller as the research object, and based on the series cell multi-levels topology structure, engaged researches on digitalized controlling technique of the controller. By the researching and developing, we realized the real time computation of the SPWM's pulse width and the controlling of the speed variation, and the tested system can be controlled and run in safe and stable.First, we analysised and compared the features of several different high voltage frequency-variation system's topology structures, and got the conclusion that the series cell multi-level topology structure has the advantages of good output wave form, easy to realize digitalized control and adapt to be used in high voltage large power frequency variable system. And we discussed the series cell frequency variation speed adjusting system from its system composition, hardware circuit and power cell in detailly.Second, on the basis of series cell multi-level topology structure, we compared several sampling methods and modulating methods by analysis, selected the method of regulated sampling and the method of carrier level phase-shift modulating. And discussed how to realize the real time computing of the SPWM's pulse width in detailly, and simulated the process. The result of the simulating shows that we can promote the equal switching freqency by the method of carrier level phase-shift modulating, and increase the numbers of the level of output wave, and make the output wave good, and the sameness of the outputed cell power. Third, we introduced the time gap, connector et. cetral concepts in software design, make the software system firmwarable. The software system adopts the modularized program design, and it realized the functions of sequence control, computing of V/f curve, compensation of stator resistance voltage-drop and the given accumulator speed adjusting.Finally, we tested the developed controller for the high voltage frequency variable device using the testing platform. The result of the testing verified that the modulating method of carrier level phase-shift SPWM is feasible, and the control method is correct. The develped system can complete the control of the frequency variable speed adjusting, and the system is running in safely and stablely.