Optimum selection of state feedback variables PWM inverters control

Different control schemes for voltage source inverter interfacing are presented and compared. Different state feedback control approaches are investigated, therein identifying a generalized optimum control variable selection criterion that is appropriate to the control of inverter systems using an LCL passive filter. A standard synchronous proportional plus integrator (PI) controller is added into the outer loop control to achieve zero steady state error. A (P) proportional inner loop control is used to provide fast dynamic compensation. Finally, system harmonic impedance expressions are derived and used to study the effects of supply voltage distortion on the harmonic performance. The presented optimum variable selection criterion has been verified through the similarities between the different inverter system waveforms and experimental implementation.