Design Optimization and Implementation of Genetic-Based Moving Sliding Manifold Strategy for Parallel Operation of DC-AC Converters

Abstract

In this paper, the optimal design to parallel operation of DC-AC converters using genetic-based moving sliding manifold strategy is proposed. The AC output voltage regulation and balanced current-sharing among the parallel modules are achieved by the use of the moving sliding manifold (MSS). However, while the load condition of the parallel-connected DC-AC converter is a large parameter variation, the chatter around the MSS occurs. The chatter may cause heat losses and high voltage harmonics in parallel-connected DC-AC converter output, and thus deteriorates system stability and reliability. To eliminate the chatter, the control gains of the MSS can be optimally adjusted by the use of the genetic algorithm (GA). With the proposed strategy, the parallel operation of the DC-AC converter yields a high-quality AC output voltage with low voltage harmonics and fast dynamic response even under large parameter variations, thus achieving more robust system. Experimental results are performed to demonstrate the proposed strategy. Index Terms—Moving sliding manifold (MSS), chatter, genetic algorithm (GA), parallel operation, DC-AC converter. I. I NTRODUCTION Owing to the design ease in thermal management and the remarkable improvement in redundancy, modularity, and maintainability, the parallel operation of DC-AC converters is popularly used in telecommunication electronic systems, like computers, LANs, Modems, Hubs, etc. The parallel operation of the DC-AC converter must supply high-quality AC output voltage with low total harmonic distortion (THD), fast dynamic response, and zero steady-state errors; these requirements can be obtained by using feedback control technologies. To provide the suitable parallel operation of DC-AC converters, a voltage control loop and a current control loop are indispensable. The voltage control loop is designed to obtain the output voltage at the desired amplitude and frequency. The current control loop is designed to control the current-sharing among the parallel modules. Generally, a proportional integral (PI) controller can be used to meet the above requirements of converter design. However,