Wei Duan

Application of hysteretic current-mode control technology for electrostatic precipitator

The electrostatic precipitator (ESP) system depends heavily on the three-phase IGBT intelligent inverter high voltage (HV) power supply. To improve the dynamic responses of ESPs during the event of flashovers and back corona, a magnificent nonlinear-controll technology called hysteretic current-mode control (HCMC) concept is proposed based on the working characteristics of ESPs. This method adapts the parameters to the load conditions of ESPs dynamically and accurately. It can also greatly improve the vibrant behavior of HV power supply with a fast variation of input voltage or load current according to different working conditions. PSIM simulation results and the physical application waveforms of JiNan Steel Group demonstrate that the valid values of current and voltage can be increased by this fast automatic adjustment control and the average corona power can also be increased to improve the ESP efficiency significantly.

Investigation on the protection system of the large power converter with IGCT

Large power three-level voltage source converters with IGCT are being used in medium or large power drive systems now and have prospective future. The protection system is very important to the safe operation of the converter. Method should be carefully taken to protect the converter when fault takes place in the converter, especially over-current due to short circuits in the load or in the converter itself. The converter system is introduced. With software simulation and experiment, the short circuit process of the converter is investigated. Then the schematic diagram of the inverter with protection system is designed. System experiment shows the converter has excellent performance.

Research on the control methods of large-power cyclo-converter under the discontinuous conduction mode

This paper presents some control methods of the discontinuous conduction mode for the controlling of a cyclo-converter. In this paper, control methods for the cyclo-converters AC current-loop are introduced and the unique issues of current control with respect to single phase circuit and three phase circuit under the discontinuous conduction mode are analyzed. Base on this, corresponding compensation algorithms are proposed to resolve these problems. Experimental results are shown to demonstrate the effectiveness of the proposed control methods.