Wide band gap (WBG) devices feature high switching frequency operation and low switching loss. They have been widely adopted in tremendous applications. Nevertheless, the manufacture cost for SiC MOSFET greater than that of the Si IGBT. To achieve a trade off between cost and efficiency, the hybrid switch, which includes the paralleling operation of Si IGBT and SiC MOSFET, is proposed. In this article, an active gate driver is used for the hybrid switch to optimize both the switching and thermal performances. The turn-on and turn-off delays between two individual switches are controlled to minimize the switching loss of traditional Si IGBT. In this way, a higher switching frequency operation can be achieved for the hybrid switch to improve the converter power density. On the other hand, the gate source voltages are adjusted to achieve an optimized thermal performance between two individual switches, which can improve the reliability of the hybrid switch. The proposed active gate driver for hybrid switch is validated with a 2 kW Boost converter.
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Four Control Freedoms AGD for Hybrid SiC MOSFET and Si IGBT Application
Silicon carbide (SiC) MOSFET features low switching loss and it is advantageous in high switching frequency application, but the manufacture per Ampere cost is approximately five times higher than the silicon (Si) IGBT. Therefore, by paralleling Si IGBT and SiC MOSFET together, a trade-off between cost and loss is achieved. In this paper, a four control freedoms active gate driver (AGD) including turn-on delay, turn-off delay, and two independent gate voltages, is proposed to optimize the performance of the paralleled device. By adjusting these four control freedoms, optimal operation for paralleled device can be obtained. Moreover, the proposed AGD can dynamically adjust the current ratio between two paralleled devices, which can help achieve thermal balance between two devices and improve system reliability. Double pulse test (DPT) experimental results are presented and analyzed to validate the effectiveness of the proposed AGD for paralleled Si IGBT and SiC MOSFET application.
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- Award ID(s):
- 1939144
- NSF-PAR ID:
- 10317584
- Date Published:
- Journal Name:
- Four Control Freedoms AGD for Hybrid SiC MOSFET and Si IGBT Application
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract—Wide band gap (WBG) devices, like silicon carbide (SiC) MOSFET has gradually replaced the traditional silicon counterpart due to their advantages of high operating temperature and fast switching speed. Paralleling operations of SiC MOSFETs are unavoidable in high power applications in order to meet the system current requirement. However, parasitics mismatches among different paralleling devices would cause current unbalance issues, which would reduce the system reliability and maximum current capability. Thus, to achieve current balancing operation, this paper proposes a solution of using multi-level active gate driver, where the dynamic current sharing during turn-on and turn-off processes are achieved by adjusting the delays, intermediate turn-on and turn-off voltages. The static current sharing is maintained by regulating the static turn-on gate voltage, where the on-state resistance mismatch between different devices can be compensated. A double pulse test setup with two different SiC MOSFETs is built to emulate the scenario of worst case application with large differences of threshold voltage and on-state resistance. The experimental results demonstrate that the proposed active gate driver can achieve both dynamic and static current sharing operations for SiC MOSFETs with paralleling operation. Moreover, the system control diagram is discussed. Simulation studies are conducted to achieve closed-loop control of the paralleled SiC MOSFETs with the aid of the active gate driver approach.more » « less
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null (Ed.)Driving solutions for power semiconductor devices are experiencing new challenges since the emerging wide bandgap power devices, such as silicon carbide (SiC), with superior performance become commercially available. Generally, high switching speed is desired due to the lower switching loss, yet high dv/dt and di/dt can result in elevated electromagnetic interference (EMI) emission, false-triggering, and other detrimental effects during switching transients. Active gate drivers (AGDs) have been proposed to balance the switching losses and the switching speed of each switching transient. The review of the in-existence AGD methodologies for SiC devices has not been reported yet. This review starts with the essence of the slew rate control and its significance. Then a comprehensive review categorizing the state-of-the-art AGD methodologies is presented. It is followed by a summary of the AGDs control and timing strategies. In this work, using AGD to reduce the EMI noise of a 10 kV SiC MOSFET system is reported. This work also highlights other capabilities of AGDs including reliability enhancement of power devices and rebalancing the mismatched electrical parameters of parallel- and series-connected devices. These application scenarios of AGDs are validated via simulation and experimental results.more » « less
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Conference Paper:
- https://doi.org/10.1109/APEC42165.2021.9487290
