JB/T 5846-1991 Guide to calculation of thyristor characteristic curves
Some standard content:
Mechanical Industry Standard of the People's Republic of China
Guide to Calculation of Thyristor Characteristic Curves
1 Subject Content and Scope of Application
JB/T5846-91
This standard provides the technical requirements, calculation formulas and methods for characteristic curves such as power consumption and current, case temperature and current, and surge current and frequency. bzxZ.net
This standard applies to reverse blocking triode thyristors and rectifier diodes. The general technical requirements and calculation methods of the corresponding characteristic curves are also applicable to bidirectional triode thyristors and reverse conducting triode thyristors. 2 Reference standards and parameter symbols
2.1 Reference standards
GB2900.32 Electrician name adjustment terminology Power semiconductor devices GB3859
GB4024
GB4939
GB4940
2.2 Parameter symbols
Semiconductor power converter
Semiconductor device Reverse blocking triode thyristor test method Ordinary rectifier
Ordinary thyristor|| tt||-On-state average current, A,
IT(RMS)——On-state root mean square (effective value) current, AITMOn-state peak current, A,
Ia(ITsM)——On-state surge current, A; VM--On-state peak voltage, V
Vro threshold voltage, V,
PT(Av)--—On-state average power, W,
P.——Peak power of surge current, W, Ti-—Thyristor junction Temperature, ℃;
Tin—the maximum operating junction temperature of the thyristor, ℃;△T:—the junction temperature rise relative to the specified reference point, ℃, Tthe case temperature of the thyristor, ℃,
the bottom width of a sine half wave, mS;
tp—the bottom width of a rectangular wave equivalent to a sine half wave, mS;T-the period of 50Hz frequency, mS;
R—the (steady-state) thermal resistance of the thyristor, ℃/WRic—the DC junction-to-case thermal resistance of the thyristor, ℃/W, Zt, Z(t) Transient thermal impedance of the thyristor, ℃/W; Transient thermal impedance of the junction of the Zie thyristor, ℃/W, A Additional thermal resistance relative to the DC thermal resistance, ℃/W, r
Differential resistance of the on-state characteristic curve, 2;
Approved by the Ministry of Machinery and Electronics Industry on October 24, 1991 170
Implementation on October 1, 1992
JB/T5846-91
Note: The unit of T is usually given in m in the data sheet or standard. F Form factor
t—The frequency of the sine wave
—The conduction angle.
3 General technical requirements for characteristic curves
3.1 Properties of characteristic curves
The basic characteristic curves of thyristors can be divided into two categories according to their origin: curves obtained by tests and curves generated by calculations. The on-state volt-ampere characteristic curve and transient thermal impedance characteristic curve should be test curves. The characteristic curves such as power consumption and current, shell temperature and current, surge current and frequency are generally calculated curves. The calculated curve should be consistent with the test verification results. 3.2 Prerequisites for calculating curves
The calculated curve is obtained by calculation from the relevant test curves under certain principle conditions. Steady-state characteristic curves such as power consumption and current, shell temperature and current are obtained from the on-state volt-ampere characteristic test curve, and transient characteristic curves such as surge current and frequency, and time are obtained from the transient thermal impedance characteristic and high operating point volt-ampere characteristic test curves. To calculate each characteristic curve, the correct relevant test curve must be obtained through experiments.
3.3 Calculation formulas and calculation tools
When calculating the curve, the mathematical formula should be selected correctly, and the meaning, unit and value range of each symbol in the formula should be correctly understood. In order to improve the efficiency and accuracy of the calculation, a calculator or computer with a program should be used as much as possible. 3.4 Coordinates of characteristic curves
The functions, variables and their coordinates of the characteristic curves of the transistor should be selected according to the general ones, and arithmetic, single logarithmic or double logarithmic coordinates should be selected according to the range of values. Appropriate selection of coordinates is necessary to correctly express the macroscopic shape of the curve and facilitate the use of the curve. In addition, the parameter disk and necessary conditions should be marked on the curve graph. 4 Technical requirements for test curves
4.1 On-state volt-ampere characteristic curve (ITM~VTM) a. The test method of the on-state volt-ampere characteristic curve should comply with the provisions of Article 3.3 of GB4024. b. Two on-state volt-ampere characteristic curves should be given under isothermal conditions of 25℃ and T. If one is given, T1 should be given. c The on-state volt-ampere characteristic curve should be the upper limit of the qualified product curve range, and the VTr value of the specified point on the curve should be equal to or slightly less than the VTAr value in the product data sheet.
d, the range of ITar values of the on-state characteristic curve: for general operating points, from zero to about 5Ir(Av), and using arithmetic coordinates to depict; for high operating points, generally from 6ITAV) to close to ITSM, and using single logarithmic coordinates to depict. e. Vro and rr should be obtained from the on-state characteristic approximate straight line of T= according to the relevant definitions of GB2900.32. 4.2 Transient thermal impedance characteristic curve (Zth~t) a. The definition of transient thermal impedance (2) and the test method of its characteristic curve should comply with Article 1.2.12 of GB2900.32 and Article 2.3 of GB4024 respectively.
d' The decomposition thermal impedance characteristic curve is depicted with single logarithmic coordinates, and the time range given by the horizontal coordinate (logarithm) should be from no less than 10-3s to thermal steady state, and the thermal steady state Z should be equal to Rh.
C. Transient thermal impedance characteristic curves are divided into junction-case transient thermal impedance (Zi) curves, junction-dissipation transient thermal impedance (Zis) curves and total transient thermal impedance (Z1a) curves. The case-rated thyristor must at least give the junction-case transient thermal impedance curve. d The time () coordinate unit of the transient thermal impedance curve is usually 3. In order to improve the accuracy of the first half of the curve, the range of t can be appropriately sacrificed and ms can be used.
In: When checking the solution thermal impedance curve, special attention should be paid to the relationship of the logarithmic scale. 171
5 Technical requirements and methods for calculating curves
5,1 Power consumption and current curves (PT(AV)~IT(A)) 5.1.1 Technical requirements
JB/T5846—91
a, the relationship curve between power consumption and current should be given with current waveform and conduction angle as parameters. Usually two curves are given for sinusoidal half-wave conduction angles of 30°, 60°, 96°, 120°, 180° and rectangular waves of 30°, 60°, 90°, 126°, 180°, 270°, and DC. The waveforms are marked on the curves, and conditions such as T value, rated power value, and load properties are also marked when necessary. For rectifiers, at least four curves should be given for six-phase, three-phase, single-phase, and DC.
b. The starting point of the curve for each conduction angle is the coordinate zero point, and the end point of each curve should be determined according to the same heat generation (root mean square current), and cannot be calculated and depicted arbitrarily.
c. To calculate this curve, the on-state volt-ampere characteristic curve (Vrc, rr) and rated Ir should be knownG. Change the conduction angle and repeat the above steps to obtain the Tc~IT(AV) curves of the sine wave conduction angles of 60°, 90°, 120° and 180°.
e. Repeat the above steps according to the rectangular wave to obtain the Tc~Ir(ay) curves of each conduction angle of the rectangular wave. 5.3 Curve of surge current and frequency (ITsM~n) 5.3.1 Technical requirements
a. The waveform of the surge current should be basically a sine waveform, and the multi-cycle surge current should meet the conditions of equal amplitude, equal bottom width and equal spacing. b. The surge current test method should comply with Article 4.2 of GB4024. c1TS~n curve is given from one cycle to at least 15 cycles, up to 300 cycles, and generally to 50 cycles. d. The junction temperature or junction temperature rise of one cycle surge current is taken as the reference temperature. The junction temperature or junction temperature rise at the end of the last cycle of two or more multi-cycle surge currents shall not exceed the reference temperature. e. To calculate IsM~n, the following should be known: Iu~VrM, Z~t and tw. f. ITsM~n is plotted on a single logarithmic coordinate, with the vertical (logarithmic) and horizontal coordinates representing ITsr and n respectively. The junction temperature before the surge and the surge current frequency are usually marked on the curve.
5.3.2 Calculation formula
a, the calculation formula for the bottom width of the rectangular wave current whose heat generation is equivalent to that of a half-sine wave current is t, =(2/n)Vrolrsy+0,5rlrsm.-
VTolsM +r-\Ts
The formula for calculating the peak power of the surge current is P= VroITsM +PrI\TSM
C, and the formula for calculating the junction temperature rise caused by the surge current is according to Appendix F of GB3859: AT; =Pm(ZC(-1)T+tJ+ZE(V-1)T) or △T=PZ(t)
d. Formula for calculating surge current of each cycle (5)
JB/T5846-91
-VTo±VVTO+4IT·△Ti/Z(t)
5.3.3 General steps for calculation
a. Generally, Vro and rT are obtained by using the high operating point on-state volt-ampere characteristic curve. b. According to formula (5), calculate the bottom width t: of the rectangular wave current equivalent to a sinusoidal half-wave surge current, and find the Z(t) value on the Z(t)~t curve.
C. According to formula (6), calculate the peak power P of a sinusoidal half-wave surge current. d. According to formula (7) or (8), calculate the peak junction temperature rise △T: (the maximum allowable value) of a sinusoidal half-wave surge current. According to formula (7), calculate the Z(t) value of each multi-cycle and substitute it into formula (9) to find the maximum allowable surge current value of each multi-cycle. For the curve with a range of 100 cycles, it is recommended to take seven calculation points of 1, 3, 5, 1C, 30, 50 and 100 cycles. f. Draw the ITsM~n curve on the single logarithmic coordinates (ITs). 5.41t~t curve
5.4.1 Technical requirements
a, I°t is actually a surge current with a sine half-wave base width (tw) shorter than the rated 50Hz half-cycle, and tw is between 0.5 and 1Cms. I in I2t is the root mean square (effective value) current. b. The test method of I2t should comply with Article 4.3 of GB4024. c. [*t~t is an isothermal curve, usually based on the junction temperature when the sinusoidal half-wave surge current has a bottom width of 10ms. d. The I\t~t curve is generally plotted using double logarithmic coordinates, and the corresponding IrsM~t curve is usually given on the same curve graph. e. According to relevant literature, the following calculation formula and method are only applicable to thyristors with a core silicon wafer diameter not greater than 5cmm and a voltage not higher than 3kV. For devices with larger capacity, due to the large expansion loss, △T increases, so that the surge current shorter than 4ms, especially below 2ms, increases very little compared to 10ms.
5.4.2 Calculation formula
a, the formula for calculating the bottom width t of a single rectangular wave power equivalent to a sinusoidal half-wave energy, that is, formula (5) in Article 5.3.2. b, the formula for calculating the peak power and peak junction temperature rise generated by the equivalent sinusoidal half-wave peak current, that is, formula (6) and formula (8) in Article 5.3.2.
When t<1ms in (8), and the Z(t)~t curve does not give the z(t) value below 1ms, the z(1ms) value of 1ms can be used to extrapolate the Z(t) value shorter than 1ms according to (10). Z(t)=(vt/Vims).Z(ims)
In the formula, t is less than 1ms and greater than the time required for the thyristor to be fully turned on. For large, medium and small thyristors, the shortest time required for full turn-on is generally 200μs, 20μs and 10μs respectively. 174
c. Formula for calculating I2t
5.4.3 General steps for calculation
JB/T5846-91
According to items a~d of 5.3.3, calculate the peak junction temperature rise △T of the sinusoidal half-wave surge current with a bottom width of 1ms:. a.
b. Take four more points between 1 and 10 ms, such as 1, 3, 5, and 7 ms, and calculate the rectangular wave bottom width tp of the four sine half-wave bottom widths according to formula (5).
According to the isothermal principle, calculate the surge current of 1, 3, 5, and 7 ms according to formulas (8) and (9). c.
d. According to (11), calculate the I2t value at each time point. Plot I2t～t and ITsM～t on the same graph of double logarithmic coordinates. e.
Additional notes:
This standard was proposed and coordinated by the Xi'an Electric Power Electronics Technology Research Institute of the Ministry of Machinery and Electronics Industry. This standard was drafted by the Xi'an Electric Power Electronics Technology Research Institute of the Ministry of Machinery and Electronics Industry. The main drafter of this standard is Qin Xianman.
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