New Dual H-Bridge Converter for Continuous Space Vector Modulation

Abstract

Multilevel converters are a significant improvement in the DC-AC conversion technology, reaching higher power quality in medium-voltage applications and using standard semiconductors in a smarter way than conventional converters, without necessarily increasing the cost. However, multilevel technology remains discrete and its only way to reduce the overall total harmonic distortion leads on the generation of several discrete levels on the output voltage. Therefore, it is not possible to reduce the harmonic distortion to negligible values, unless a big number of semiconductors are used, which is not cost-effective for low-voltage applications, limiting the reliability of the system. This study proposes a new dual H-bridge inverter that generates a three-phase output voltage with negligible distortion using two variable DC-DC power sources and a new continuous space vector modulation. Simulation and experimental results show high-quality output voltages. The topology is simple and uses only 12 semiconductors, but it requires special attention in the variable DC voltage converters, which can limit the maximum output frequency. Therefore, the solution is suitable for low power applications that require high power quality using small filters or none filters at the AC side. The results were obtained and validated using an experimental laboratory prototype under different operating conditions.