Enhanced Deadtime Compensation Strategy Combining Current Prediction and Drive Pulse Rectification for Three-Phase VSI

Abstract

In voltage source inverters (VSI), deadtime interval is imperative to avoid short circuits in the same bridge arm. Its presence distorts the output voltage and thus impacts the control performance of VSI. Conventional pulse rectification strategy measures the current through each control cycle and use the polarity of the resulting current value to modify the drive pulse. Given that the current values obtained by the classic scheme based on phase current sampling are not the actual currents corresponding to the deadtime transients. Hence this article introduces an enhanced deadtime compensation strategy combining current prediction and drive pulse rectification for three-phase VSI. The improved scheme constructs the actual current values corresponding to the deadtime transients by calculating the current ripple trajectory in real-time during each control cycle and compensating based on it. This can significantly raise the accuracy of phase current polarity judgement. Simulations and experiments have confirmed the validity and practicality of the presented method.