Performance assessment and optimization of control system parameters for a positive output luo converter using novel techniques

Abstract

The Positive Output Luo Converter (POLC) is a general purpose DC to DC converter with buck and boost features. The topology of the POLC is simple, and it has the added advantage that the polarity of the output voltage does not reverse with respect to the input voltage. Since the main power control switch is in series with the input DC source, whenever the output from the POLC is not required it can be completely shut down or switched off by keeping the power control switch in the OFF state. As far as the topology of the POLC is concerned, it consists of four storage elements in the form of two inductors and two capacitors, the power control switch and the power direction regulating diode. The presence of four energy storage elements increases the order of the transfer function of the converter. The characteristic of the converter becomes nonlinear. In this work, the usage of a PI controller is demonstrated for the voltage regulation of the output DC voltage of the POLC. To start with, the Zeigler Nicholas method of tuning the PI controller is done. Using the Kp and the Ki values as supplied by the Zeigler Nicholas method of tuning the performance of the POLC with a PI controller, under source and load disturbances as well as tracking performance under changing commands are also studied and recorded. The Kp and the Ki values as obtained from the Zeigler Nicholas method are used as the initial values for the optimization techniques that are further developed. newline