Advanced self-commissioning and feed-forward compensation of inverter non-linearities

Accurate compensation of inverter non-linearities is highly desirable especially in high performance drives where a perfect correspondence between reference voltages and real output voltages is required. In this paper a self-commissioning procedure able to determine each contribute to the overall output voltage distortion and save it to a Look-Up Table (LUT) is described along with a detailed theoretical analysis of the different causes and effects of each non-linearity. The procedure is based on Sine-Triangle Pulse Width Modulation (ST-PWM), requires two additional relays and can be carried out autonomously by an inverter controller. A feed-forward compensation approach based on the extracted data is proposed for ST-PWM and for Space Vector Modulation (SVM) techniques. The feasibility and effectiveness of the proposed solution are demonstrated by experimental results.