Development of an Improved Tristate Buck–Boost Converter With Optimized Type-3 Controller

In this paper, the design and development of tristate buck-boost converter with particle swarm optimization (PSO)-based optimized Type-3 controller is discussed. In the conventional buck-boost converter, a right-half-plane (RHP) zero is present in its control-to-output transfer function. So, it becomes difficult to design controller for the converter, which is operating in continuous conduction mode. Converter performance deteriorates due to the presence of RHP zero in its control-to-output transfer function. The proposed tristate buck-boost converter has no RHP zero in its control-to-output transfer function. In closed-loop control, PSO-based optimized Type-3 controller has been designed and utilized to improve the transient and steady-state performances. Simulation and experimental results of the proposed converter have been presented and compared with the conventional buck-boost converter. The proposed converter exhibits faster transient and steady-state characteristic and it can be used wherever fast transient response with step-up/step-down of source voltage is needed and also be useful for drive applications, electric vehicles, photovoltaic system, and so on. In this paper, the PSO-based optimized Type-3 control technique is newly introduced to enhance the closed-loop performance of tristate buck-boost converter and not been reported earlier in any literature. The closed-loop converter is very cheap and easily implantable due to the use of simple control logic by utilizing few analog components.