An SVM Scheme for Three-Level Quasi-Switched Boost T-Type Inverter With Enhanced Voltage Gain and Capacitor Voltage Balance

This article introduces a space vector control method for the three-level quasi-switched boost T-type inverter, which provides some benefits such as: good output voltage quality, high voltage gain, and low voltage stress on power devices. By applying corresponding P-type or N-type small vectors in switching sequence, the neutral-point voltage unbalance problem can be solved easily. The advantage of this modulation solution is that it does not require any extra calculations. The upper-shoot-through and lower-shoot-through states are utilized instead of full-shoot-through, which is usually used in traditional single-stage three-level impedance source inverter, to ensure the boost capability of the inverter. These states are inserted into small vectors in order not to affect the output line-to-line voltage. Some investigations about voltage gain, diode, and switch voltage stress have been conducted to demonstrate the effectiveness of the proposed method. The experimental results are also presented to validate the accuracy of the proposed modulation method. The proposed approach has resulted in efficiency rise by 2% as compared to the conventional PWM scheme.