vol. 51 no. 2 fuji electric review 48 kiyoshi sekigawa hiroshi endo hiroki wakimoto u-series of igbt-ipms (600 v) 1. introduction intelligent power modules (ipms) are intelligent power devices that incorporate drive circuits, protec- tion circuits or other functionality into a modular configuration. ipms are widely used in motor driving (general purpose inverter, servo, air conditioning, elevator, etc.) and power supply (ups, pv, etc.) applications. the equipment that uses these ipms are required to have small size, high efficiency, low noise, long service life and high reliability. in response to these requirements, in 1997, fuji electric developed the industry? first internal over- heat protection function for insulated gate bipolar transistors (igbts) and developed an r-ipm series that achieved high reliability by employing an all- silicon construction that enabled a reduction in the number of components used. then in 2002, fuji electric changed the structure of its igbt chips from the punch through (pt) structure, which had been in use previously, to a non-punch through (npt) structure, for which lifetime control is unnecessary, in order to realize lower turn-off loss at high temperature, and also established finer planar gate and thin wafer processing technology to develop an r- ipm3 series that realizes low conduction loss. with the goal of reducing loss even further, fuji electric has developed an igbt device that employs a trench npt structure to realize lower conduction loss and has developed a new free wheeling diode (fwd) structure to improve the tradeoff between switching noise and loss. both of these technologies are incorpo- rated into fuji electric? newly developed u-series igbt-ipm (u-ipm) which is introduced below. 2. u-ipm development concepts and product line-up the concepts behind the development of the u-ipm are listed below. (1) realization of lower loss lower loss can be realized by developing new power elements and optimizing the drive performance. increasing the carrier frequency of the equipment contributes to improved control performance. also, larger output can be obtained from the equipment during the operation at the same carrier frequency. (2) continued use of the same package as prior products table 1 product line-up, characteristics and internal functions of the u-ipm series no. of elements inverter part brake part internal function pa c kage type both upper and lower arms upper arm lower arm v dc (v) v ces (v) 450 6 in 1 7 in 1 600 450 600 i c (a) p c (w) i c (a) p c (w) dr: igbt driving circuit, uv : under voltage lockout for control circuit, tjoh: device overheat protection, oc: over-current pr otection, alm: alarm output, tcoh: case temperature over-heat protection *6mbp20rua060 uses a shunt resistance-based over-current detection method at the n line. model dr uv oc alm oc alm tjoh tcoh 6mbp 20rua060 20 84 yes yes yes none none none p619 yes yes 6mbp 50rua060 50 176 yes yes yes yes none yes p610 yes yes 6mbp 80rua060 80 283 yes yes yes yes none yes p610 yes yes 6mbp100rua060 100 360 yes yes yes yes none yes p611 yes yes 6mbp160rua060 160 431 yes yes yes yes none yes p611 yes yes 7mbp 50rua060 50 176 30 120 yes yes yes yes none yes p610 yes yes 7mbp 80rua060 80 283 50 176 yes yes yes yes none yes p610 yes yes 7mbp100rua060 100 360 50 176 yes yes yes yes none yes p611 yes yes 7MBP160RUA060 160 431 50 176 yes yes yes yes none yes p611 yes yes free datasheet http://www..net/
u-series of igbt-ipms (600 v) 49 the continued use of the same package as with prior products makes it possible to improve equipment performance by replacing the ipm without having to modify the design of the equipment. table 1 lists the product line-up, characteristics and internal functions of fuji electric? 600 v u-ipm series. the u-ipm series maintains internal functions and a package size that are interchangeable with the r-ipm series; its rated current is 20 to 160 a for the ? in 1?pack and 50 to 160 a for the ? in 1?pack (containing an internal igbt for braking use). figure 1 shows an external view of the packages. 3. characteristics of the power devices a fifth-generation u-series igbt (u-igbt) is used as the power device. this u-igbt combines trench gate technology with a basic design comprising fuji electric? floating zone (fz) wafer technology, thin wafer processing technology, carrier injection control technology, and transportation factor improving tech- nology. figure 2 compares the structures of the convention- al planar igbt and the trench igbt. the adoption of fig.1 external view of u-ipm packages a trench gate structure results in a smaller voltage drop at the channel (r-ch) due to increased surface cell density and results in a lower saturation voltage due to the smaller voltage drop resulting from the elimination of the planar device? characteristic j fet region (r- jfet). moreover, short circuit immunity capability is realized through optimization of the design of the surface structure. figure 3 illustrates the changes that have occurred in the cross-sectional igbt structure in the transition from the conventional igbt to the u- igbt, and table 2 compares their applied technologies. the fwd, in accordance with the u-igbt, incorpo- rates a new design featuring optimized wafer specifica- tion, control of anode-side injection and optimal life- time control technology to realize the characteristics of low peak current during reverse recovery operation, low generated loss, and soft recovery. 4. u-ipm loss 4.1 comparison of total loss the marketplace requires that new ipm products achieve lower levels of loss. (1) increased carrier frequency to enhance controllability and (2) larger output current at the same carrier frequency are necessary for the achievement of the goal. the loss table 2 changes in igbt technology fig.2 comparison of planar igbt and trench igbt chip cross sections fig.3 change in cross-sectional structure of 600 v igbt chip p619 p610 p611 n + source p - c hannel emitter electrode (a) planar igbt (b) trench igbt insulation layer gate electrode gate oxide layer n - silicon substrate n + source p - c hannel r - ch r - acc r - jfet r - drift r - drift r - acc r - ch v - pn v - pn p + layer collector electrode igbt technology r-ipm r-ipm3 u-ipm n-igbt t-igbt u-igbt epitaxial w afer fz 350 m w afer thickness 100 m pt structure npt planar gate structure trench ye s lifetime control none high carrier injection low low transportation factor high n + buffer n - p n + n + p + substrate n - n - p p u - ipm trench npt structure r - ipm3 planar npt structure thinner surface r - ipm planar pt structure c ge ge ge c c free datasheet http://www..net/
vol. 51 no. 2 fuji electric review 50 fig.4 comparison of total loss (at same current) for the u-ipm, r-ipm3 and r-ipm series fig.5 current vs. total loss (at same frequency) for u-ipm, r- ipm3 and r-ipm generated by existing models and by the u-ipm is described below. figure 4 compares the loss of the u-ipm and the existing r-ipm and r-ipm3 devices in the case of operation at carrier frequencies of 4, 8 and 16 khz, and a current of 50 arms (1 /3 of the rated current). as can be seen in the figure, the newly developed u-ipm realizes a total loss that is approximately 22 to 28 % lower than that of the r-ipm and approximately 11 to 12 % lower than that of the r-ipm3. in particular, it can be seen that the loss generated when using the u- ipm at a carrier frequency of 8 khz is less than the loss generated by a r-ipm operating at a carrier frequency of 4 khz, and therefore, the carrier frequen- cy can be increased from 4 khz to 8 khz by replacing a r-ipm with a u-ipm of the same size package. moreover, according to fig. 5 which shows the relation- ship between current and total loss at f c =4 khz, to generate the same amount of loss (50 w) as the r-ipm, the output current of the u-ipm can be increased by 24.5 % compared to that of the r-ipm, or increased by 13.7 % compared to that of the r-ipm3. these techniques for reducing loss were focused on reducing the conduction loss, which accounts for more than 50 % of the total loss, and on reducing the turn-on fig.6 i c - v ce characteristics for u-ipm, r-ipm3 and r-ipm total loss (w) 20 0 40 60 80 100 r - ipm : 6mbp150ra060 r - ipm3 : 6mbp150rtb060 u - ipm : 6mbp160rua060 t j = 125 c, e d = 300 v v cc = 15 v, i o = 50 arms power factor = 0.85, =1 p rr p f p off p on p sat r - ipm 45.50 26.9 6.13 7.01 4.12 1.34 r - ipm3 f c = 4 khz 40.55 26.3 5.76 3.03 3.90 1.59 u - ipm 22.2 4.21 3.85 3.89 1.22 r - ipm 59.80 26.7 12.3 14.0 4.12 2.68 r - ipm3 f c = 8 khz 50.90 26.2 11.6 6.04 3.90 3.18 u - ipm 44.57 22.1 8.46 7.68 3.89 2.44 r - ipm 88.79 26.7 24.7 27.9 4.12 5.37 r - ipm3 f c = 16 khz 71.67 26.1 23.2 12.1 3.89 6.38 u - ipm 63.08 22.0 17.0 15.3 3.89 4.89 35.37 100 150 50 0 total loss (w) 120 100 80 60 40 20 0 r - ipm r - ipm3 u - ipm 53 a 58 a 66 a i o (arms) r - ipm : 6mbp150ra060 r - ipm3 : 6mbp150rtb060 u - ipm : 6mbp160rua060 t j = 125 c, e d = 300 v f c = 4 khz, v cc = 15 v power factor = 0.85, =1 v ce (sat) (v) i c (a) 1.5 2 2.5 3 3.5 1 0.5 0 50 0 100 150 r - ipm3 r - ipm u - ipm t j = 125 c, v cc = 15 v v ce (sat) at ipm pin free datasheet http://www..net/
u-series of igbt-ipms (600 v) 51 the emission noise. (1) application of the new soft recovery fwd sup- presses dv / dt . (2) the capacitance between the gate and emitter is optimized in order to reduce di / dt , which in- creased as a result of the lower gate resistance, without reducing dv / dt through application of the above techniques, even if currents of all sizes are controlled with the same gate resistance, emission noise will be maintained at the same level as that of the r-ipm3 as shown in fig. 8 , and lower loss can be realized. accordingly, the total loss generated in all these products is linearly proportional to the current, and the total loss and temperature rise that occur during actual use can easily be estimated. 5. conclusion fuji electric? 600 v u-ipm that uses a u-series igbt chip having a trench npt structure has been described above. this u-ipm provides suitable perfor- mance to satisfy the marketplace in which lower loss is required. in the future, fuji electric intends to continue to develop new ipms that will satisfy market requirements. fig.7 characteristics of turn-on waveform and emission noise table 3 characteristics of gate resistance and turn-on waveform fig.8 emission noise loss, which accounts for a large percentage of the switching loss of the r-ipm3. each type of loss reduction is described below. 4.2 reduction of conduction loss figure 6 shows i c - v ce(sat) characteristics for u- ipm, r-ipm3 and r-ipm devices. it can be seen that when i c =1 50 a, the v ce(sat) of the u-ipm is 0.45 v less than that of the r-ipm and 0.55 v less than that of the i-rpm3. this is the v ce(sat) reduction effect due to the trench igbt described in chapter 3 . 4.3 turn-on loss and emission noise figure 7 shows a schematic drawing of the current ( i c ) and voltage ( v ce ) at the time when the device is turned on. as can be seen in the figure, typically, loss can be reduced by making dv / dt larger and emission noise can be reduced by making di / dt smaller. howev- er, in the case where turn-on operation is controlled by the typical method of gate resistance only, there is a tradeoff relation as shown in table 3 , and it is difficult to establish both high dv / dt and low di / dt simulta- neously. in the newly developed u-ipm, the following two techniques suppress the emission noise that usually increases when gate resistance is decreased and di / dt is increased, thereby enabling di / dt to be increased and turn-on loss to be decreased without any increase in low noise low loss v ge v ce i c t 1 t 2 t 1 : time from i c = 0 until i c = i cp t 2 : time from i c = i cp until v ce = 0 di / dt is small and t 1 is long low emission noise dv / dt is large and t 2 is short low loss gate resistance r g high low low increases decreases low high high decreases increases turn-on di / dt turn-on dv / dt loss emission noise measurement conditions: distance between servo amplifier and antenna is 2 m, vertical direction, standby state emission noise level (db v/m) frequency (mhz) (a) r - ipm3 (150rtb) (b) u - ipm (160rua) frequency (mhz) 80 30 50 100 emission noise level (db v/m) 80 130 130 30 50 100 free datasheet http://www..net/
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