| There have been several advances in various areas of power converters in the past few decades. New technologies for passive components, switches and diodes have greatly reduced the size of power converters and have also increased their efficiency. The issues in control of power converters have been relatively sidelined with respect to issues in other areas of power conversion such as efficiency, magnetics, etc. This dissertation addresses issues in regard to the control of switching power converters and proposes solutions to improve the performance of the control loop.;Right half plane (RHP) zero, present in boost and buck-boost type converters, poses a major challenge for the control loop design of such converters. The zero restricts the bandwidth of the control loop and also results in lower phase margin for the control loop. This dissertation proposes a technique to eliminate the RHP zero from the control loop of boost converters. It is shown in the dissertation that it is possible to move the RHP zero and place it at a desired frequency in the left half plane. The proposed technique has been analyzed and various conclusions are drawn from the theory, simulations, and experimentation. Improvements to phase margin of the control loop using the proposed technique has been demonstrated on a prototype boost converter.;Other control related issue is the non-linear nature of boost and buck-boost converters which results in sub-optimal performance behavior, when they are designed to deliver a wide range of output voltages. The non-linear nature in boost converters is analyzed and the background of a non-linear control technique of input-output linearization is discussed and applied to boost converters. The dissertation proposes a novel technique called Adaptive Input Output Linearization (AIOL), to address the non-linear nature of boost converters. It is shown that the proposed non-linear control technique can be performed with the use of only analog components. The proposed adaptive technique works independent of the plant component values. Performance and stability of a prototype boost converter control loop with the proposed AIOL technique is demonstrated at various operating points of the output voltage. Lastly, the technique of AIOL is digitally implemented on Point of Load buck converters. It is shown that the technique provides tolerance to output capacitance variation over a wide range. Performance of the technique is experimentally verified and demonstrated on a prototype buck converter and the results are compared with traditional control loop design. |
