Prospects of Using Class D Amplifiers in Microgrid Systems with Nonlinear Loads

Modern methods for mitigating nonlinear inverter voltage distortions in low-power microgrid systems are considered: proportional-resonant/multi-resonant controllers, virtual impedance and droop control, dual voltage inverters, and self-oscillating class D amplifiers. The study outlines the fundamental properties and the principle of parasitic harmonic mitigation. Special attention is paid to the number of controllers required to implement each of the methods, the effectiveness of nonlinear distortion mitigation through the study of the number of harmonics, and the reduction of the total harmonic distortion with and without the application of each method. The compatibility of each method with the output power controller is also analyzed. The benefits and drawbacks of existing methods are analyzed, as well as the prospects of using a self-oscillating class D amplifier for the control of nonlinear distortions in microgrid systems.