Two-Mode H-bridge Based DC Electric Spring for DC-Bus Voltage Stabilization

This paper presents a two-mode H-bridge-based DC electric spring (DCES) to address the dc-bus voltage unbalance issue. The proposed scheme operates in two modes, (i) suppressing mode (SM), (ii) boosting mode (BM). When the dc-bus voltage exceeds a reference critical value, the DCES operates in SM to suppress the voltage, while if the dc-bus voltage falls below the reference critical value, the DCES switches to BM to boost the voltage. The primary objective in both modes is to regulate the dc-bus voltage to its required reference value. In case of large unbalances in the dc-bus voltage the common practice is to use a battery based DCES to tackle the voltage variations. However, this paper proposes a feedback boost converter-based which is DCES. This eliminates the battery limitation as well as reduces the variation in non-critical load voltage and current, thereby regulating the critical voltage to its reference value. The proposed two modes and boost converter-based DCES is verified with mathematical modelling and simulation results to validate the effectiveness and feasibility.