Series-Connected IGBTs Using Active Voltage Control Technique
TL;DR: In this article, an active control technique for series-connected IGBTs that allows their dynamic voltage transition dVce/dt to adaptively vary is presented, and the switching losses associated with this technique are minimized by the adaptive dv/dt control technique incorporated into the design.
Abstract: With series insulated-gate bipolar transistor (IGBT) operation, well-matched gate drives will not ensure balanced dynamic voltage sharing between the switching devices. Rather, it is IGBT parasitic capacitances, mainly gate-to-collector capacitance Cgc, that dominate transient voltage sharing. As Cgc is collector voltage dependant and is significantly larger during the initial turn-off transition, it dominates IGBT dynamic voltage sharing. This paper presents an active control technique for series-connected IGBTs that allows their dynamic voltage transition dVce/dt to adaptively vary. Both switch ON and OFF transitions are controlled to follow a predefined dVce/dt. Switching losses associated with this technique are minimized by the adaptive dv/dt control technique incorporated into the design. A detailed description of the control circuits is presented in this paper. Experimental results with up to three series devices in a single-ended dc chopper circuit, operating at various low voltage and current levels, are used to illustrate the performance of the proposed technique.
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01 Jan 2015
TL;DR: In this paper, a closed-loop IGBT gate driver using simple passive diC /dt and dvCE /dt feedbacks and employing a single analog PI-controller is proposed.
Abstract: This paper proposes a new concept for attaining a defined switching behavior of insulated-gate bipolar transistors (IGBTs) at inductive load (hard) switching, which is a key prerequisite for optimizing the switching behavior in terms of switching losses and electromagnetic interference (EMI). First, state-of-theart gate driver concepts that enable a control of the IGBT’s switching transients are reviewed. Thereafter, a highly dynamic closedloop IGBT gate driver using simple passive diC /dt and dvCE /dt feedbacks and employing a single analog PI-controller is proposed. Contrary to conventional passive gate drivers, this concept enables an individual control of the current and voltage slopes largely independent of the specific parameters or nonlinearities of the IGBT. Accordingly, a means for optimizing the tradeoff between switching losses, switching delay times, reverse recovery current of the freewheeling diode, turn-off overvoltage, and EMI is gained. The operating principle of the new gate driver is described and based on derived control oriented models of the IGBT, a stability analysis of the closed-loop control is carried out for different IGBT modules. Finally, the proposed concept is experimentally verified for different IGBT modules and compared to a conventional resistive gate driver.
146 citations
Cites background from "Series-Connected IGBTs Using Active..."
...7 was proposed, investigated, and gradually developed further in [28]–[33]....
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TL;DR: A novel method is proposed for balancing the dynamic voltages among series-connected silicon carbide (SiC) MOSFETs with high dv/dt rates using a small capacitor at turn-off, which generates negligible losses in the control circuit, and also does not significantly increase the switching losses of the semiconductors.
Abstract: Series connection of individual semiconductors is an effective way to achieve higher voltage switches. However, the inherent unequal dynamic voltage sharing problem needs to be solved, even when well-matched gate drivers and semiconductors are used. A majority of the existing voltage balancing schemes are developed for slow-switching silicon (Si)-based semiconductors, and are also associated with a significant amount of additional losses in the control circuit or on the switches. In this paper, a novel method is proposed for balancing the dynamic voltages among series-connected silicon carbide (SiC) MOSFETs with high dv/dt rates. The method takes advantage of a small capacitor to provide additional current to the gate of the MOSFETs at turn- off , meaning the switching speed (and thus, the device voltage after turn- off ) is controlled. The proposed method generates negligible losses in the control circuit, and also does not significantly increase the switching losses of the semiconductors. Experimental results are provided to prove the effectiveness of the proposed voltage balancing scheme on two SiC MOSFETs inside a module connected in series. In order to do so, an active gate driver is designed embedding the active dv/dt control scheme as well as other essential functionalities needed for operation of SiC MOSFETs.
111 citations
TL;DR: In this article, an active voltage balancing control technique is proposed to solve the asynchronous gate delay problem in series-connected IGBTs in highvoltage and high-power converters.
Abstract: Transient voltage unbalance is the major problem that limits the application of series-connected IGBTs in high-voltage and high-power converters. Asynchronous gate delay causes series-connected IGBTs not to turn-on and turn-off at the same time resulting in severely unbalanced voltage sharing. An active voltage balancing control technique is proposed in this paper to solve the asynchronous gate delay problem. By sampling the feedback signal caused by unbalanced voltage sharing, the microcontroller generates a time delay for the gate driver to compensate the asynchronous gate delay. The most vital part of active voltage balancing control, the status feedback circuit, is also discussed in detail in this paper. The function of the status feedback circuit and the effect of active voltage balancing control are verified in a two series-connected HV-IGBTs platform in rated operation (5 kV bus voltage and 600 A load current).
90 citations
Cites background from "Series-Connected IGBTs Using Active..."
...The voltage unbalance caused by tail current difference is also shown in [13] and [18]....
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TL;DR: Using AGD to reduce the EMI noise of a 10-kV SiC MOSFET system is reported and other capabilities of AGDs are highlighted, including reliability enhancement of power devices and rebalancing the mismatched electrical parameters of parallel- and series-connected devices.
Abstract: 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.
85 citations
TL;DR: In this paper, a closed-loop IGBT gate driver using simple passive feedback was proposed to optimize the tradeoff between switching losses, switching delay times, reverse recovery current of the freewheeling diode, turnoff overvoltage, and EMI.
Abstract: This paper proposes a new concept for attaining a defined switching behavior of insulated-gate bipolar transistors (IGBTs) at inductive load (hard) switching, which is a key prerequisite for optimizing the switching behavior in terms of switching losses and electromagnetic interference (EMI). First, state-of-the-art gate driver concepts that enable a control of the IGBT's switching transients are reviewed. Thereafter, a highly dynamic closed-loop IGBT gate driver using simple passive ${\rm d}i_{\rm C}/{\rm d}t$ and ${\rm d}v_{\rm CE}/{\rm d}t$ feedbacks and employing a single analog PI-controller is proposed. Contrary to conventional passive gate drivers, this concept enables an individual control of the current and voltage slopes largely independent of the specific parameters or nonlinearities of the IGBT. Accordingly, a means for optimizing the tradeoff between switching losses, switching delay times, reverse recovery current of the freewheeling diode, turn-off overvoltage, and EMI is gained. The operating principle of the new gate driver is described and based on derived control oriented models of the IGBT, a stability analysis of the closed-loop control is carried out for different IGBT modules. Finally, the proposed concept is experimentally verified for different IGBT modules and compared to a conventional resistive gate driver.
83 citations
References
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TL;DR: In this paper, the authors review recent trends in power semiconductor device technology that are leading to improvements in power losses for power electronic systems and predict that silicon carbide based switches will begin to displace these silicon devices.
Abstract: This paper reviews recent trends in power semiconductor device technology that are leading to improvements in power losses for power electronic systems. In the case of low voltage ( 100 V) power rectifiers, the silicon P-i-N rectifier continues to dominate but significant improvements are expected by the introduction of the silicon MPS rectifier followed by the GaAs and SiC based Schottky rectifiers. Equally important developments are occurring in power switch technology. The silicon bipolar power transistor has been displaced by silicon power MOSFETs in low voltage ( 100 V) systems. The process technology for these MOS-gated devices has shifted from V-MOS in the early 1970s to DMOS in the 1980s, with more recent introduction of the UMOS technology in the 1990s. For the very high power systems, the thyristor and GTO continue to dominate, but significant effort is underway to develop MOS-gated thyristors (MCTs, ESTs, DG-BRTs) to replace them before the turn of the century. Beyond that time frame, it is projected that silicon carbide based switches will begin to displace these silicon devices.
507 citations
"Series-Connected IGBTs Using Active..." refers background in this paper
...Referring to the equations in [4], the turn-off delay time td(off ) and IGBT transconductance gm are related by...
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TL;DR: In this paper, a first-order model for the temperature dependence of threshold voltage in thin-film silicon-on-insulator (SOI) n-MOSFETs is described.
Abstract: A first-order model for the temperature dependence of threshold voltage in thin-film silicon-on-insulator (SOI) n-MOSFETs is described. The temperature dependence of the threshold voltage of thin-film SOI n-channel MOSFETs is analyzed. Threshold voltage variation with temperature is significantly smaller in thin-film (fully depleted) devices than in thick-film SOI and bulk devices. The threshold voltage is shown to be dependent on the depletion level of the device, i.e. whether it is fully depleted or not. There exists a critical temperature below which the device is fully depleted, and above which the device operates in the thick-film regime. >
152 citations
"Series-Connected IGBTs Using Active..." refers background in this paper
...Increased temperature reduces IGBT gate threshold voltage [6]....
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01 Jun 2001
TL;DR: Recently, significant improvements in the performance of silicon-power MOSFETs has been achieved by using innovative vertical structures with charge coupled regions, and silicon IGBTs continue to dominate the medium- and high-voltage application space sue to scaling of their voltage ratings and refinements to their gate structure achieve by using very large scale integration (VLSI) technology and trench gate regions.
Abstract: Power electronic systems have benefited greatly during the past ten years from the revolutionary advances that have occurred in power discrete devices. The introduction of power metal-oxide-semiconductor field-effect transistors (MOSFETs) in the 1970s and the insulated gate bipolar transistors (IGBTs) in the 1980s enabled design of very compact high-efficiency systems due to the greatly enhanced power gain resulting from the high input impedance of these structures. Recently, significant improvements in the performance of silicon-power MOSFETs has been achieved by using innovative vertical structures with charge coupled regions. Meanwhile, silicon IGBTs continue to dominate the medium- and high-voltage application space sue to scaling of their voltage ratings and refinements to their gate structure achieved by using very large scale integration (VLSI) technology and trench gate regions. Research on a variety of MOS-gated thyristors has also been conducted, resulting in some promising improvements in the tradeoff between on-state power loss, switching power loss, and the safe-operating-area. Concurrent improvements in power rectifiers have been achieved at low-voltage ratings using Schottky rectifier structures containing trenches and at high-voltage ratings using structures that combine junction and Schottky barrier contacts. On the longer term, silicon carbide Schottky rectifiers and power MOSFETs offer at least another tenfold improvement in performance. Although the projected performance enhancements have been experimentally demonstrated, the defect density and cost of the starting material are determining the pace of commercialization of this technology at present.
140 citations
"Series-Connected IGBTs Using Active..." refers background in this paper
...IN order to overcome the limited voltage ratings of semiconductor switching devices [1], medium-voltage and highvoltage, high-power inverters utilize series-connected switching...
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TL;DR: In this article, the reverse-recovery failure modes in modern fast power diodes are investigated by using semiconductor device simulation tools, and operating conditions at which both diode snappy recovery and dynamic avalanching occur during the recovery period in modern high-frequency power electronic applications.
Abstract: In this paper, reverse-recovery failure modes in modern fast power diodes are investigated. By the aid of semiconductor device simulation tools, a better view is obtained for the physical process, and operating conditions at which both diode snappy recovery and dynamic avalanching occur during the recovery period in modern high-frequency power electronic applications. The work presented here confirms that the reverse-recovery process can by expressed by means of diode capacitance effects which influence the reverse-recovery characteristics. The paper also shows that the control of the carrier gradient and the remaining stored charge in the drift region during the recovery phase influence both failure modes and determine if the diode exhibits soft, snappy, or dynamic avalanche recovery characteristics.
112 citations
"Series-Connected IGBTs Using Active..." refers background in this paper
...reverse recovery snap can induce IGBT failure [13]....
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23 Jun 1996
TL;DR: In this paper, active gate-controlled voltage balancing and gate-side di/dt control as well as dv/dt-control are presented in theory and with measurement results.
Abstract: Increasing the operation voltage and hence the switching power by series connection of IGBT-modules causes transient and static voltage imbalances. To achieve snubberless operation, novel gate-control strategies have been developed. Active gate-controlled voltage balancing and gate-side di/dt-control as well as dv/dt-control are presented in theory and with measurement results.
83 citations