Pure sinusoidal output current-source inverter using inductor modules

A novel topology of a current-source inverter (CSI) is proposed in the paper, which can deliver a pure sinusoidal current waveform without sacrificing its efficiency and its equipment size. The proposed circuit has a hybrid structure, and combines a switching-operation based multilevel CSI and a linear current amplifier with a low-amplitude current output. The former multilevel CSI employs multiple inductor modules to generate a staircase multilevel current waveform, while the latter linear amplifier generates a compensating current to reform the staircase multilevel waveform to the pure sinusoidal waveform. Because the most part of the output current is created by the switching-operation based multilevel CSI, the system efficiency hardly deteriorates. In addition, the system does not require large LC filters because it directly delivers the pure sinusoidal current to the load. In the paper, current drooping phenomenon of the inductor modules due to their power losses is discussed, and the countermeasure is proposed.