A High-efficiency Cascade Multilevel Class-D Amplifier with Sliding Mode Control

The article presents a new switch-mode power amplifier based on a cascade multilevel topology. The amplifier adopts phase-shifted PWM technology and enjoys a switching frequency, which is 2N times of that of a single unit. It has a small total output voltage ripple and only requires a small filter to suppress the switching frequency harmonics. The article lays emphasis on the design of the sliding mode control and deducts the parameters, and then develops a 2kW cascade multilevel class-D power amplifier adopting sliding mode control. The research results show that this kind of amplifier significantly increases the system bandwidth, provides the system with fast following performance and stability, high efficiency, and low THD value of output signals, no matter the system is under resistive load or bridge rectifier load.