A Bipolar SEPIC Converter with Wide Output Voltage Range

poster abstractEnergy Systems and Power Electronics Laboratory, Purdue School of Engineering, IUPUI. In order to pursue a perfect inverter, a new inverter technology is designed based on SEPIC converter that can efficiently generate pure sinusoidal waveforms and operate in a wide range of loading conditions. The groundbreaking design of the new inverter is that, for the first time, the number of high-frequency switching-transistors is reduced to one. By changing the switching frequency and duty cycle for the switch, the voltage-level of the output signal will be continuously controlled to produce a nearly pure sinusoidal waveform, and the voltage-level can reach infinity without using any switch map in theory. In order to achieve the DC to AC conversion, inversing the polarity and the boost operation for the output voltage are the two main problems in the process of achieving this goal. To proof the possibility of the new inverter technology, a research for a bipolar SEPIC converter is firstly proposed in order to achieve the voltage polarity inversion and the boost operation. The research basically use a diode to regulate the current direction that goes through the load. By changing the direction of the diode, the polarity of the output voltage can be inversed. For the boost operation, a simulation setup in Simulink and some actual tests have been used to find out the sizes for each elements in the circuit that can boost the output voltage of the converter to 110V at a specific frequency and duty cycle of the only switch. The result of the research had showed that this converter not only had the capability to provide a very wide output voltage ranges and power levels, but also can generate output voltage and power levels for positive and negative polarities

A Selective Polarity DC-DC Converter with Virtually Infinite Voltage Levels

Indiana University-Purdue University Indianapolis (IUPUI)This research introduces a new design of a converter modified from SEPIC converter (Single end primary inductive converter), capable of generating desired voltage levels and polarities. The new switching converter topology allows for boost and buck of the input voltage theoretically achieving infinite positive and negative voltage levels. The proposed topology utilizes single high frequency switch to perform the power conversion which simplifies the design of the gate driver, but meanwhile, it still retains the ability to provide a wide range of output voltage. Mathematical modeling of the converter and computer simulations are validated by experimental data. To verify its performance a prototype was designed and built. It is experimentally proven that the circuit can generate a desired voltage in the range of voltages up to ±170 V, delivering 480 Watts of power to a resistive load