Development of a Controller Based on Compensation of Fourier Series Coefficients of Voltage Error for Stand-Alone Inverters

In this paper, we present the development of a controller for stand-alone inverters used in voltage source applications. From the controller point of view, the control system of such inverters must have fast dynamic response to track a sinusoidal reference while suppressing the perturbations caused by various disturbances such as dead-time effect and harmonic currents and maintaining stability under all load conditions. The single-loop control approaches cannot generate high quality outputs under nonlinear loads since the instantaneous control of the output voltage is very difficult and requires large amount of control design effort. Therefore, this research proposes an effective and simple harmonic cancellation technique that solves the tracking problem of such inverters. The controller is designed and simulated to prove the concept. Simulation results verified a significantly low total harmonic distortion (THD) that is equal to 1.84% under 3.3 kW nonlinear load. Then, a proof of concept experimental inverter has been built and tested with a rectifier load at 1.1 kW. The THD is measured as 0.995%. In conclusion, the results demonstrate the superiority of the proposed harmonic cancellation algorithm in the controller design of high-performance voltage source inverters.