The Topology Analysing of a Cascade Multilevel Class-D Power Amplifier

A novel switch-mode power amplifier based on a cascade multicell multilevel circuit topology is introduced in the paper. The pulse width modulated class D power amplifier has an efficiency of more than 90% compared with the other power amplifiers, however its performances such as bandwidth, distortion and stability are inferior to those of the conventional class A or B. The most significant drawback of class D power amplifiers is their low bandwidth, a trade-off has to be made among the signal frequency, filter cutoff frequency and switching frequency. The cascades H-bridge multilevel inverter uses multiple units of H-bridge power cells connected in a series chain to produce high ac voltages. The paper main analyzes the topology of a cascade multilevel class-D power amplifier´s, based on analyzing a Single-phase H-bridge inverter´s unipolar PWM modulation schemes. Then a cascade multilevel class-D power amplifier is built in the laboratory. The results of measurements taken from a laboratory setup are presented. The system shows an excellent response and stability.