A Hybrid Overload Current Limiting and Short Circuit Protection Scheme for Voltage Mode Inverters

In this study, a current limiting technique which combines an analog comparator circuit and a digital current limiting algorithm is proposed for voltage mode - controlled inverters. Thus, providing smooth output voltage waveform feature of digital current limiting technique and very fast response feature of the analog technique are combined. A three-phase 10kVA voltage mode - controlled inverter has been used to test the performance of the proposed method. Besides, the digital and the analog current limiting techniques have been tested separately to highlight and compare the performance of the proposed hybrid method. It is seen from experimental tests that the proposed technique provides fast response and a successful current limiting performance at short circuit and overcurrent conditions. In addition, the proposed method improves the reliability and fault tolerance capability of the inverter significantly. Moreover, the proposed current limiting algorithm adds fault clearing capability function to the inverter.