Three-Level Indirect Matrix Converter With Neutral-Point Potential Balance Scheme for Adjustable Speed Drives

To improve the performance and explore a new solution of adjustable speed drive systems, a T-type three-level indirect matrix converter (T3LIMC) topology and its modulation scheme are presented in this article. The presented topology is composed of an LC input filter, a current-source rectifier, and a T-type three-level inverter, where the split dc source voltage of the inverter is formed by two input line-line voltages and the neutral-point voltage. A multicarrier-based modulation scheme for the inverter and a specific zero-sequence voltage are also developed, and the desired neutral-point current of the inverter is constructed to compensate for the input currents. Consequently, the balanced neutral-point potential and symmetric sinusoidal input currents are achieved without additional control effort. In addition to advantages such as bidirectional power flow, sinusoidal input-output currents, controllable input power factor, no dc-link energy storage elements, and compact structure, the T3LIMC also improves the output waveform quality by generating the three-level output voltages. Meanwhile, the zero current switching (ZCS) operation of the rectifier helps to improve efficiency. Finally, the functionality and effectiveness of the presented topology and modulation scheme are verified by experimental results.