Circulating Current Inhibition Characteristic of the Parallel Inverters Using Close-loop Adjustment of Instantaneous Voltage Feedback

This study investigated outputting circulation current inhibition characteristic that is controlled by the instantaneous feedback voltage in inverter parallel driving of the mine hoist. We established the transfer function of the parallel inverters controlled by the close-loop adjustment of the instantaneous voltage feedback. The influence of the parameters of the close-loop feedback circuit to the inhibition effects to the outputting circulation current are observed. After analysis of circulating current inhibition characteristic, the proportion integration (PI) controller is introduced into the close-loop adjustment by the instantaneous voltage feedback. The characteristic equation is gained to determine the PI parameters by the drawing of the Bode plots. The inhibition effects of the proposed controller are examined by the established simulation model of parallel inverter system. The harmonic distortion rate at the outputting voltage frequency values of 4Hz, 10Hz, 20Hz, 41Hz and 50Hz are all low than 2.32% by the outputting voltage instantaneous feedback.