A Bipolar DC Grid-Interfaced Integrated Dual Input Converter With Reduced Overloading Under Unbalanced Line Voltage Conditions

The bipolar dc microgrid configuration ensures enhanced efficiency, flexibility, and improved power quality compared to unipolar dc-based distribution. However, a bipolar structure is susceptible to voltage imbalance caused by asymmetric loading between its two poles. In such cases, power electronic converters with constant power characteristics can provide additional overload to these bipolar lines. This article presents a novel three-port dc–dc power electronic interface whose impedance can be dynamically adjusted to regulate both the pole voltage magnitudes (under balanced or unbalanced conditions) with reduced overloading while feeding a constant power load. The performance of the proposed configuration has been assessed using a three-port structure referred to as the integrated dual input converter (IDIC). The analysis of the converter operating modes, its pulsewidth modulation control, and the closed-loop system design for the bipolar dc distribution interface has been developed in this article. The theory of operation and control behavior has been validated using experimental testing on a laboratory scale prototype of IDIC.