1、PDF外文：http:/ High-Energy Pulse-Switching Characteristics of Thyristors Abstract Experiments were conducted to study the high energy, high dildt pulse-switchingcharacteristics of SCR's with and without the amplifying gate. High dildt. high-energy single- shotexperiments were first done. Dev
2、ices without the amplifying gate performed much better than thedevices with the amplifying gate. A physical model is presented to describe the role of the amplifying gate in the turn-on process, thereby explaining the differences in the switching characteristics. The turn-on area for the failure of
3、the devices was theoretically estimated and correlated with observations. This allowed calculation of the current density required for failure. Since the failure of these devices under high dildt conditions was thermal in nature, a simulation using a finite-element method was performed to estimate t
4、he temperature rise in the devices. The results from this simulation showed that the temperature rise was significantly higher in the devices with the amplifying gate than in the devices without the amplifying gate. From these results, the safe operating frequencies for all the devices under high di
5、ldt conditions was estimated. These estimates were confirmed by experimentally stressing the devices under high di/dt repetitive operation. I. INTRODUCTION Recent innovations in semiconductor device designs and advances in manufacturing technologies have helped evolve high-power thyrist
6、ors. These devices are designed to operate in a continuous mode for applications such as ac- to-dc power conversion and motor drives. Until recently, their application to high-power pulse switching was mostly unknown. One of the main reasons that has discouraged the use of thyristors for high-speed,
7、 high-energy switching is their low dildt rating. The limiting value of the dildt before damage occurs is related to the size of the initial turn-on area and the spreading velocity I. Recent experimental results presented in 2-4 show that with increased gate device, SCR's and GTO's having hi
8、ghly interdigitated gate-cathode structures can reliably operate under high dildt conditions on a single-shot basis. Previously, SCR's have also been used for repetitive switching of 1 kA, 10 ps wide pulses having a dildt of about 10 000 Alps, at 500 and 800 Hz for a 10 h period SI. It is report
9、ed in 6 that GTO modules (five devices in series) can block 11.5 kV and switch 4.5 kA pulses having a dildt of 2500 A/ks at frequencies of 100 Hz. Asymmetric devices, such as the ASCR's in a stack assisted by saturable inductors, have shown the potential to repetitively switch high-current pulse
10、s with di/dt of about 2000 Alps, on the order of kilohertz 7. Under high dildt conditions the junction temperatures can vary rapidly in high-power devices ( 610 /Cs ) 8. The failure of these devices under these conditions is normally thermal in nature. It has been reported 9,that the temperatu
11、re of destruction due to a tum-on dildt failure is in the range of1100 1300 C , below the melting point of silicon (1415C). The rise in average temperature is therefore completely inade- quate as a measure of device applicability for pulse-switching applications. Since a simple experimental techniqu
12、e is not available to measure the instantaneous temperature rise, the spatio-temporal distribution of temperatures in the devices has to be estimated using computer-aided techniques. In this paper, the high dildt single-shot experimental re- sults are given in brief. A qualitative physical mod
13、el is then proposed to explain the experimental results, which are presented in detail elsewhere 3. Next, the results from the thermal analysis using FEM, given in detail in lo, are briefly presented. The particulars of the experimental arrangement for the repetitive testing of the devices, results
14、from these experi- ments, and their correlation with the numerical predictions are given in the discussion. 11. SINGLE-SHOTEXPERIMENTS Inverter-grade SCR's with the amplifying gate (unshorted device) and without the amplifying gate (shorted device) were used for experimental studies
15、 to determine the role of the amplifying gate during the turn-on processes of the device. The SCR's used for the tests were symmetric with involute gate-cathode structures. They were rated for a forward and reverse blocking voltage of 2.4 kV (at 25C) and 2.2. kV (at 125C). The experimental detai
16、ls and results are fully presented elsewhere 3. The experimental arrangement and the results are given in brief below. The devices were electrically characterized initially and recharacterized after testing in a type E pulse-formingnetwork (PFN) that has a total impedance of 0.1 0. This networ
17、k delivers a 15 kA, 10 ps wide pulse when charged to a voltage of 2.5 kV. The di/dt of this 15-kA pulse is 125000 /As . The gate trigger used for switching the SCR's was a 100 A, 500 ns trapezoidal current pulse.The di/dt of the gate pulse was 980 /As . The unshorted devices failed while s
18、witching a peak anode current of 10.5 kA at a dildt of about 26000 /As in a PFN charged to 1.7 kV. Under the same trigger conditions, the shorted devices successfully switched 13 kA at a dildt of 100000 /As , in a PFN charged to 2 kV.A comparison of the performance of the two types of devices is presented in Table I. The ampliyfing gate seems to inhibit the tum-on
