Predictive control vs. linear control for current control of a single-leg inverter

This paper presents a comparison of a predictive control scheme with a linear regulator for current control of a single-leg inverter driving a resistive-inductive load with back-EMF. The comparison is motivated by the fact that in most comparisons the linear regulator is not tuned optimally, i.e. it is just providing a suboptimal result. In this paper an oversampled linear resonant regulator is compared to a regularly sampled deadbeat-like predictive control scheme. Due to the fact that both controllers should be implemented on an FPGA for a first approximation it is assumed that the control outputs can be calculated within one FPGA clock cycle. The future reference values are unknown and - despite this fact - the reference should be tracked as accurately as possible. It will be shown that in general a predictive control formulation leads to one sample delay which must not be confused with the more familiar calculation delay for software-based implementations of regularly sampled controller implementations.