Multiple resonant controller with load-adaptive phase compensation capabilities

The use of voltage source inverters (VSI) in microgrid stand-alone applications needs the accurate control of the filter output voltages. Resonant controllers represent a good tradeoff between implementation issues and control performance. However, the un-known nature and size of connected loads, from the control point of view, affect the dynamic control behavior and may reduce the effectiveness of the harmonic controllers. The proposed multiple resonant controller is on-line tuned according to the designed filter and load behavior which may change during the converter operation. In this manner, several harmonic compensators can be placed in the loop to achieve better output voltage waveform, (i.e. lower total harmonic distortion).