dc Bus If |Iu | ≤ |Imax| + |Band|, Enable = 1; Otherwise, Enable = 0. Iu |U | + Iumax - Link Converter Enabled Vu PWM Enable Enabled VvPWM Enable Enabled Band Vu PWM dc/ac Iv |U | + Iv max - Band MCB 4 MCB 3 MCB 2 MCB 1 VvPWM Iw |U | + Load 4 Load 3 Load 2 Load 1 Iw max VvPWM - Band VvPWM (a) (b) Iabc Without Current Limitation Control 8 6 4 2 Iabc (p.u.) Iabc (p.u.) Enable 0 -2 -4 -6 -8 0 0.02 0.04 0.06 0.08 Time (s) (c) 0.1 0.12 0.14 3 2.5 2 1.5 1 0.5 0 -0.5 -1 -1.5 -2 -2.5 -3 Iabc With Current Limitation Control 0 0.02 0.04 0.06 0.08 Time (s) (d) 0.1 0.12 0.14 Figure 4. The link converters short-circuit fault ride-through function: the (a) discrimination of MCB 3 for faulty hotel load 3, (b) current limitation control logic, and (c) and (d) comparison of fault current occurring at 0.05 s. Without current limitation control, the fault current reaches to 7 per unit (p.u.) and has a large asymmetry. With current limitation control, the fault current is controlled to 2.5 p.u., which is adequate for MCB disconnection. IEEE Elec trific ation Magazine / S EP T EM BE R 2 0 2 0 33