Introduction to Elimination of RHP Zero for the Improvement of Performance of Boost Converter Project:
We first revisit the small signal modeling of a CCM boost converter, and confirm the presence of a RHP zero in its control-to-output transfer function. We then explain the operation of a tri-state boost converter. We carry out the formulation of the open-loop small signal model of the same. We discuss the choice of control variables for possible elimination of the RHP zero. Finally, we propose a current control scheme for the tri-state boost converter circuit configuration.
The proposed scheme (a) completely eliminates the RHP zero, (b) Gives a superior dynamic performance in comparison with the schemes proposed earlier, (c) Achieves a step up ratio greater than 3 with stable periodic behavior without the use of a compensation ramp. We discuss the need of feed-forward control in enlarging the operating region, improving dynamic performance and efficiency. We carry out fast scale stability analysis and slow scale transient analysis. We validate the theoretically predicted behavior experimentally. Finally, we briefly discuss about the elimination of the RHP zero in a buck-boost converter.
A Conventional Boost Converter
The schematic of a conventional boost converter is shown in Fig. 1. For a dc-dc boost converter, if the MOSFET on-time (related to the duty ratio) is increased, the capacitor discharge time increases which implies a reduction in the output voltage. The output voltage continues to dip further until the inductor gets sufficient energy to build it up again, which results in an initial undershoot of the output voltage.
Future Plan
- We improve the performance of boost converter by the improving of this technology by designing the values of parameter k1, k2, k3, kp, & ki.
- Use other techniques for tri-state boost converter control like the constant charging interval and dual mode control, recently proposed in the literature.
- Implement this topology for Buck- Boost Converter.