Current source inverters (CSI) offer advantages of voltage boost, short-circuit protection, reduced electromagnetic interference, and direct regeneration. While CSI control strategies are less developed than for voltage source inverters (VSI), the topologies are functional duals and have much in common in a control sense. In particular, since CSI voltage regulation is the dual of VSI current regulation, current regulation control strategies for a VSI can be readily implemented as equivalent voltage control strategies for a CSI. This paper shows how a high-performance proportional-integral stationary frame and P+Resonant CSI voltage regulator can be analytically designed and optimized, while in particular taking into account the second-order response of a CSI filter/load combination.