Proposal of nonlinear deadbeat control for boost converter and the experimental verification

This thesis discusses the proposal of nonlinear deadbeat control for continuous conduction
mode (CCM) boost converter and the experimental verification. First, the nonlinear state
equation is derived, and second a nonlinear current reference deadbeat control is proposed.
Third, a new nonlinear controller to implement the load disturbance compensation is proposed.
Then the simulations using PSIM software and verifications by experiments, it is confirmed that
under the conditions of an input voltage 12 V, an output voltage of 20 V, a load resistance of 4 Ω
and a sampling frequency of 100 kHz, the voltage command tracking capability of a settling time
of 280 μs is achieved, and an output voltage recovery time of 1.46 ms is achieved for a sudden
unknown load change. Mathematical analysis is performed to confirm asymptotic stability
and robustness of the control method during voltage and current perturbation, disturbance
occurrence and parameter variations. It is found that the voltage and current errors eigen
values converge towards inside of the unit circle thus maintaining asymptotic stability for each
perturbation case investigated. Methods to design the controller parameters are stipulated to
be within the physical realization and can be applied to boost converter of any application in
CCM. The proposed control method is compared with other literature that applied different
digital control methods to boost converters of various applications. It is found that nonlinear
deadbeat control proposed in this thesis is about twice as fast for reference tracking response,
and can reject disturbances quickly for a load current three times bigger than other literature.
Therefore, it is concluded that these data are the best even though the proposed control is based
on nonlinear equations. Few differences are observed between experiments and simulations.
Further investigations reveal the cause to be time delay in the switching device and other un-
modeled nonlinear switching device phenomena. Future work will focus on improving the control
method to compensate for nonlinearities.