| Abstract |
A successful use of series connected strings of MOSFETs or IGBTs requires equalizing the dynamic and static voltage sharing across the devices. The dynamic voltage imbalance is generally managed via the slope control of the output voltages by capacitor networks, or by active balancing circuits on the gate side. The main issues that related to the performances of series connected strings of devices are faced. In particular, evaluations are performed among the assisted switching behaviours obtained with conventional load side circuits, and those obtained with a new circuit acting on the gate side. Experimental tests are carried out in order to evaluate the impact of the actual control actions on the devices, with reference to the power consumption, the commutation times, and the drive requirements. Commutations of a single switch are used as reference to compare the performances of multiple switch connections, in case of an equal voltage blocking capability of the single and the multiple switches. Advantages and disadvantages of the assisted transient switching are treated extensively, in order to acquire a deeper insight on the industrial feasibility of the proposed active voltage sharing circuit. |
