Abstract : This paper describes several commonly used modules in frequency converter applications, such as IGCT, IEGT, GTO, and IGBT. Through calculation and comparative analysis, it is concluded that IGBT is currently the device with a better cost performance. Keywords : IGBT module, calculation and analysis [b]1. Overview[/b] Due to the backwardness of China's component industry, it is not yet able to produce high-voltage IGBTs, and Western countries still impose a technology blockade on China. For example, 6500V IGBTs are still not exported to China, regardless of their high price. The choice of power switching device in direct series technology is crucial to determining the cost performance of frequency converters. Currently, there are several devices available, such as IGCT, IEGT, GTO, and IGBT, and IGBTs are further divided into 1700V, 3300V, and 6500V. Each device manufacturer claims that its device is the best. Which device has a better cost performance? Let's make some specific comparisons, based on the technical parameters listed in the product catalogs of each manufacturer. [b]2. Several Commonly Used Power Devices[/b] The development of frequency converters has always been accompanied by the development of power electronic devices. Whenever there's a new leap forward in power electronic devices, there will inevitably be a new leap forward in frequency converters, and new frequency converters will inevitably emerge. In the 1950s, silicon thyristors (SCRs) appeared; in the 1960s, gate-turn-off thyristors (GTOs) appeared; in the 1970s, high-power transistors (GTRs) and power MOSFETs appeared; in the 1980s, insulated-gate bipolar transistors (IGBTs), gated thyristors (IGCTs), and power-enhanced injection type insulated-gate transistors (IEGTs) appeared successively; and in the 1990s, intelligent power modules (IPMs) appeared. Due to the emergence of these components, frequency converters based on these inverter devices emerged. Conversely, frequency converters require inverter devices to have ideal static characteristics: high voltage withstand capability in the blocking state; high current flow and low on-state voltage drop, low loss, and low heat generation in the conducting state; short on/off times (i.e., high switching frequency) and high du/dt withstand capability during switching state transitions; full control functionality; long lifespan; compact structure; small size; and, of course, low cost. Some of the aforementioned power electronic devices meet only partial requirements, while others are gradually developing in this direction to achieve perfection. This is especially true for medium (high) voltage frequency converters, which require components with high voltage resistance. 3. Module Selection Analysis 3.1 Relevant Definitions and Formulas Taking the design of a medium-voltage frequency converter as an example, with a DC operating voltage of 3600V, and assuming a motor power factor of 0.8, a carrier frequency of 3kHz, and an output frequency of 50Hz, the following formulas are used to estimate the specifications of a switching component of the frequency converter using different power switching devices. Using a peak current Icp of 400A, the following estimation formulas are used: 1. Stable power consumption; 2. Switching power consumption; 3. Total power consumption. 3.2 IGBT Module Calculation Analysis First, we compare 1700V, 3300V, and 6500V IGBTs. To achieve a 3600V operating voltage for the medium-voltage frequency converter, four 1700V transistors need to be connected in series, or two 3300V transistors need to be connected in series; the 6500V transistors should not be connected in series. (1) Four 1700V tubes are connected in series. The model is FZ400R17E3. The relevant technical data is as follows: Uce(sat) = 2.4V Esw(on) = 150mJ Esw(off) = 125mJ Pss = 0.1425 ∠400 ∠2.4 ∠4 = 547.2W Psw = 955.4 ∠(Esw(on) + Esw(off) ∠4 = 955.4 ∠(0.15 + 0.125) ∠4 = 1050W Then Pc1 = Pss + Psw = 547.2 + 1050 = 1597W (2) Two 3300V IGBTs are connected in series. The model is FF400R33KF2. The relevant technical data is as follows: Uce(sat) = 2.8V Esw(on) = 960MJ Esw(off) =510mJ Then Psw=955.4Î(Esw(on)+Esw(off))Î2 =955.4Î(0.91+0.51)Î2=2808W Pss=0.1425Î400Î2.8Î2=319W Pc2=Pss+Psw=319+2808=3127W (3) Use one 6500V IGBT, model FZ400R65KF1, its relevant technical data is as follows: Uce(sat)=3.9V Esw(on)=4J Esw(off)=2.3J Then Pss=0.1425Î400Î3.9=222W Psw=955.4Î(4+2.3)=6019W Pc3 = Pss + Psw = 222 + 6019 = 6241W 3.3 IEGT Module Calculation and Analysis We compare the IEGT with a 1700V IGBT, keeping other conditions unchanged. For the IEGT, we choose the ST750GXH21 model, whose relevant technical data is as follows: Icp = 750A, Uce = 4.5V, Ucc = 2400V, Esw(on) = 2.5J, Esw(off) = 3J. Therefore, Pss = 0.1425 * Icp * Uce(sat) = 0.1425 * 750 * 4.5 = 481W, Psw = 955.4 * (Esw(on) + Esw(off)) = 955.4 * (2.5 + 3) = 5255W. Pc4 = Pss + Psw = 481 + 5255 = 5736W Since its operating voltage Ucc=2700V, three FZ400R17E3 transistors are connected in series, and then two series are connected in parallel. The calculated power consumption is: Pc5=2396W . 4. Conclusion: IGCT performs worse than 6500V IGBT or IEGT, so IGCT will not be compared here. Now, let's compare the above calculation results. When performing the exact same task, using a 1700V IGBT device as the benchmark, the power consumption ratio of devices at different voltage levels is as follows: 1700V IGBT Pc1/Pc1=1597÷1597=1 3300V IGBT Pc2/Pc1=3127÷1597=2 6500V IGBT Pc3/Pc1=6241÷1597=3.9 4500V IEGT Pc4/Pc5=5736÷2396=2.39 From the above calculations, it can be seen that using 1700V IGBTs in series in 6KV and 10KV high-voltage frequency converters has significant advantages: 1. Under the same losses, low-voltage IGBTs can achieve a higher switching frequency, thus obtaining a better output voltage waveform. Conversely, if other components have higher switching losses, heat dissipation becomes a major problem, and the only solution is to reduce the switching frequency, which inevitably leads to a worse waveform and decreased performance. 2. 1700V IGBT inverter components have been widely used in China's steel, power, petrochemical, coal mining, cement and building materials industries since 2000. They have rich experience in operation and commissioning, mature production technology, reliable quality, and ample supply. 3. As the market matures, the price difference becomes even more significant. Note: The author is Mr. Wu Jialin, President of Jialing Company. This article was first published in "Inverter World" Issue 5, 2004.