Adaptive Sliding Mode Control for a Boost Converter with Constant Power Load

Output voltage regulation in a boost converter with Constant Power Load (CPL) can be obtained by means of sliding-mode control with a linear estimation loop of the output power. The estimation procedure is a simple integrator of the output voltage error and confers an adaptive nature on the switching regulator. Two switching surfaces of quadratic type are considered to induce the sliding motions, and the corresponding conditions for the existence of both sliding mode and stability of the equilibrium point are derived. The resulting controller can be implemented using simple analog electronics requiring operational amplifier-based circuits in both cases plus a multiplier in one case and a multiplier and a divider in the other case. PSIM and MATLAB simulations show a fast recovery and zero steady-state output voltage error in response to large-signal disturbances in the output voltage and the load power.