Performance Evaluation of an Active Neutral-Point-Clamped Multilevel Converter for Active Filtering in G2V-V2G and V2H Applications

Abstract

This paper presents the performance evaluation of a proposed single-phase bidirectional active neutral-point-clamped (ANPC) five-level converter (5LC) for active filtering in grid-to-vehicle (G2V), vehicle-to-grid (V2G) and vehicle-to-home (V2H) applications. In the system, the 5LC is series-connected with an electric vehicle battery charger based on a dual active half-bridge DC-DC converter (DAHBC). A cascaded strategy with a proportional-resonant compensator controls the 5LC whereas the DAHBC is controlled by a single phase-shift technique. A performance comparison is carried out for the proposed topology versus three NPC/ANPC 5L converters found in literature with similar topologies. The simulation results obtained in MATLAB-SimPowerSystems along with the experimental results obtained from a laboratory prototype validate the following: a) the first two literature topologies have the highest efficiencies, but they are incapable of balancing the voltage of the split-capacitors what increases the total harmonic distortion of both the grid current in the G2V/V2G modes and the 5LC output voltage in the V2H mode while producing a sluggish transient response, b) the 3rd literature topology like the proposed one properly balance the capacitors voltage and achieve a faster dynamics, but at the expense of an efficiency reduction, and c) unlike the former topology that continuously applies a natural but wasting unfedback voltage balancing strategy, the proposed one that includes a closed-loop control allows achieving an ANPC 5LC with a superior performance featured by a higher efficiency, a reduced switches stress, a flatter power losses distribution and a better power quality improving under the three modes of operation.

Keywords

• Five-level converter
• ANPC topology
• capacitor’s voltage balancing
• active filter
• power quality
• electric vehicle