Research And Design On Controller For High Voltage Device Inverter

The cascaded multilevel inverter has become to a hotspot in the industry of power electronic. It has much advancement, such as little pollution to the input, almost sine wave of output and no need of filter for output, etc. The controller of the high voltage inverter is the kernel of the high voltage frequency variable speed adjusting system, and this topic takes the controller as the research object, based on the series cell multi-levels topology structure. By the researching and developing, we finished the hardware design for the inverter controller and realized the real time computation of the SPWM pulse width and the controlling of the speed variation, and the tested system can be controlled and run in safe and stable.First, we analyzed and compared the features of several different high voltage inverter system topology structures, and introduced specially the series cell multi-level topology structure, which is used as our experiment system, from its system constitute, hardware circuit and power cell in detail.Second, on the basis of series cell multi-level topology structure, we compared several sampling methods and modulating methods by simulations. According to the results of the simulations, it shows that we can promote the equal switching frequency 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 output power for all cell power.Third, we finished the software design and hardware design of the controller. For the hardware design, we present the coupling, including the DSP board, plus extension board and the CAN bus part. For the software design, we discussed the design of speeding control, which is handled by DSP, and how to realize the real time computing of the SPWM pulse width in detail, also CAN bus communication design.Finally, we tested the developed controller for the high voltage inverter device. The result of the testing verified that this controller can complete the control of the frequency variable and speed adjusting, and the modulating method of carrier level phase-shift SPWM. It is running in safely and stable.