Dead-time issues in predictive current control

Abstract

Current control in inverter driven machine systems is arguably the most important part of the control system. If accurate and rapid current control is achieved then, given the correct reference currents, fast and accurate torque control can be achieved. Unfortunately the implementation of current control in power electronic systems is not ideal. Practical effects can have a significant influence on its performance. This paper examines one of these effects, dead-time, and considers the influence it has on the performance of predictive current controllers (PCCs). The paper presents analysis that shows that PCC implicitly compensates for voltage loss due to dead-time. Also a modified PCC is introduced that reduces the zero current clamp problem caused by dead-time. Simulation and experimental results are presented to verify the analysis and confirm the performance of the new algorithm.