| Abstract |
A circulating current is a major problem introduced by directly connecting voltage source inverter (VSI)in parallel. This circulating current occurs as a zero-sequence current between the inverters by specicswitch states. Its alternatives were presented by hardware and software methods in many papers. Whencoupled inductor (CI) are employed for the high frequency circulating current, a circulating current controlleris required to avoid the saturation of the CIs by the low frequency circulating current. In thischapter, the zero sequence circulating current (ZSCC) and its alternatives are investigated by the hardwareand mathematical descriptions. A high performance circulating current controller is proposed byapplying are repetitive controller (RC) to the zero-sequence current control loop. The proposed controllercan effectively minimize the low frequency circulating current without any data sharing betweenthe inverters in unfavorable conditions. Furthermore, this can be applicable to modular congurations ofparallel three-phase VSIs. The performance of the proposed controller is veried by the simulations andexperiments. |
