Switched Boost Inverter With PWM Control And Development Of A Prototype Model

Abstract

ABSTRACT:The objective in this paper is to study the operating modes and analysis of the Switched Boost Inverter (SBI). The performance of the proposed SBI is similar to that of Z-Source Inverter (ZSI). In comparison to the ZSI, the present topology results in lower volume and lower cost since it reduces the number of passive component. This feature makes it more suitable for low power applications than ZSI.For the proper operation of the inverter, with special consideration to its operating principle (shoot-through i.e., conduction of two switches on the same leg of the inverter), a modified PWM control strategy is also described in detail. In addition, mathematical relations between various performance parameters under this modified PWM technique have been described in detail.Simulation is carried out using Matlab/Simulink software to verify the theoretical analysis made. This report also presents a laboratory prototype of the Switched boost inverter along with it results.KEYWORDS: Z-Source Inverter, Switched Boost Inverter, Modified PWM technique, Shoot-through, Non-Shootthrough. I.INTRODUCTIONZSI employs a unique impedance network to couple the converter circuit to the power source, thus providing unique characteristic features that cannot be found in the traditional Voltage source inverter and Current source inverter. The unique impedance network mentioned above, implements two capacitors and two inductors. Introduction of these passive components add weight and size to the whole inverter. In order to reduce size and weight, a new topology is considered which involves lesser passive components, meanwhile trying to attempt similarity in all the steady state performance. This new topology is called Switched Boost inverter, which is being studied and analysed in this report. II. LITERATURE SURVEYThe basic idea of SBI [2] is derived from ZSI [1]. By controlling the shoot-through duty cycle, the ZSI can be able to produce any AC output voltage from a given DC input voltage. This feature makes the ZSI suitable for number of applications such as renewable power systems (photovoltaic and fuel cells), adjustable speed drives, general purpose motor drives, electric vehicles, uninterruptible power supplies [3]-[8] etc.Conventional pulse-width modulation techniques can be modified strategically to affect the operation of ZSI continuously or discontinuously, while retaining all the harmonic performance features of the conventional modulation techniques [9]. The complete analytical performance of the ZSI using X-shaped LC impedance network is complicated. Hence a small signal model method is resorted in [10] to derive transfer function and asses the performance there upon. From literature survey it is evident that ZSI is a promising technology for both buck and boost operations. But ZSI has the drawback of employing more and bulky passive components. Therefore SBI topology has been proposed [2] to reduce the number of passive components, thus can be used in low power applications where size and weight matters.