Design Optimization of Quasi-Active Gate Control for Series-Connected Power Devices

Abstract

This paper presents a new gate drive circuit for driving a series string of IGBTs. The proposed quasi active gate control (QAGC) circuit is simple to implement as it composes of only a few passive components in addition to a standard gate driver. No separate isolation power supply is required for the upper devices in the stack. The proposed QAGC circuit provides an effective way to drive the power devices and control static and dynamic voltage sharing to the devices at the same time. The theoretical switching operation and the oscillation stability analysis allow criteria for component selection to be established. Limitations of the QAGC circuit is also identified. The modification of the circuit to support more power devices in the series stack is discussed with the aid of the simulation results. The switching operation of the circuit is validated from the experimental results using 2 IGBTs connected in series. The circuit shows a satisfied switching operation with well-controlled dynamic and static voltage sharing and comparable gate voltage between the coupled devices.

Reconfiguration of NPC Multilevel Inverters to Mitigate Short Circuit Faults Using Back-to-Back Switches

“…To resolve this issue, a proper voltage balancing technique for series-connected semiconductors is chosen. Two main considerations are 1) The voltage balancing technique should use a separate gate driving circuit for each device since one driving circuit for several semiconductors is not applicable to the original healthy operation (an example technique that is not applicable here is shown in [41]); 2) The voltage balancing technique should not have the components which are not necessary for the original healthy operation. Taking both considerations into account, a hybrid voltage balancing method for series-connected semiconductors in [40] is chosen.…”

Voltage Balance Switching Scheme for Series-Connected SiC MOSFET LLC Resonant Converter

“…Quasi-active gate control (QAGC) [37,38] is a combination of snubber circuits and the AVC method. This method has the advantage that the number of additional devices is small and the circuit is simple.…”

Physical Investigation Into Effective Voltage Balancing by Temporary Clamp Technique for the Series Connection of IGBTs

“…Series connection of IGBTs is an effective way to increase the rated voltage of power electronic converters. This approach is increasingly widely used in high-voltage and high-power power conversion systems such as HVDC transmission system [1][2][3][4], pulsed-power applications [5] and et al It could result in a real improvement of the total weight, volume, and cost of the whole converter, thanks to the possibility of both reducing energy losses and increasing operating switching frequency. The advantages have been presented when compared with the well-known modular multilevel converter (MMC) with much easier control strategy and half device number [3].…”

“…There are several methods to minimize the voltage difference across individual IGBT in the series string [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15].…”

“…A novel hybrid voltagebalancing technique is proposed to achieve voltage balancing with minimum total losses [7]. A quasi-active gate control is proposed to provide dynamic and static voltage sharing by using a simple RC balancing network and a single gate drive with the parameter optimization discussed in [4].…”