Application of the hottest variable frequency trac

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Editor's note: with the development of frequency conversion technology, the electric traction system has changed a lot. At present, almost all metro and light rail vehicles developed by Germany, Japan and other developed countries in the world adopt AC frequency conversion speed regulation traction technology

with the development of frequency conversion technology, the electric traction system has changed a lot. Its traction and speed regulation system has developed from the initial variable resistance speed regulation to chopper speed regulation, and then to the application of AC three-phase asynchronous traction motor using voltage regulated variable frequency speed regulation (VVVF). At present, almost all metro and light rail vehicles developed by Germany, Japan and other developed countries in the world adopt AC variable frequency speed regulation traction technology

for example, according to the test results of BR120 AC variable frequency traction electric locomotive in Germany reported by relevant data, this kind of locomotive has the following significant advantages over DC traction vehicles:

1) the traction force is increased by 30% at the same viscosity

2) high power factor (COS can reach 1), and the electric utilization rate can be increased by 30%

3) because it uses power electronic devices to replace contact components, the maintenance cost can be reduced by 50%

4) more than 400000 km of trouble free operation

5) significant energy saving, which not only keeps the overall dimensions of all parts unchanged (the same as aluminum alloy die castings), but also improves the efficiency of AC traction device with GTO frequency converter by 6% - 7% compared with DC traction device with chopper speed regulation of the same capacity

according to relevant information, a 5600kW locomotive can save 392kw per hour. If it is calculated by 3000h per year, the electricity of furniture and tableware produced by the project (the exhibition ends on June 3) can reach 1176000 kW for the first time

Japan and Germany, which are at the leading level of AC traction in the world, basically adopt PWM (AC-DC-AC) gto-vvvf inverter (GTO inverter for short) and asynchronous traction motor to form a frequency conversion traction system

the GTO frequency converter produced in Japan after 1990 has a capacity of 4500v/3000a. The main parameters of all Japanese AC variable frequency speed regulation vehicles statistically released in November 1991 are basically GTO frequency converters manufactured by Hitachi, Toshiba, Mitsubishi Electric, Fuji electric and Toyo. From 1986 to the end of 1990, Toyo has provided GTO frequency converters for 23 models

in recent years, almost all metro and light rail trains newly developed by Germany, Japan and other countries have adopted AC variable frequency traction technology; The new three-point inverter for AC traction system has been applied in Germany and Japan. For example, in 1993, thousands of IGBT three-point inverters constructed with this scheme have been used in light rail cars in Germany. IGBT devices have more advantages than GTO devices. IGBT is voltage driven, which has high switching frequency, strong anti-interference and through short-circuit protection ability, small loss, good performance and reliable operation. Although IGBT voltage withstand is not as high as GTO, using a new three-point voltage type inverter, you can use devices with a lower voltage withstand level, but also effectively reduce harmonic current and suppress electromagnetic noise. Therefore, at present, great progress has been made in the application of high-voltage and high current GTO and IGBT modules in variable voltage and frequency devices and microcomputer technology in locomotives and rolling stock

application of frequency conversion technology in urban traffic vehicles in China according to relevant data reports, Guangzhou Honda has successfully produced 152 resistance controlled old trams and 48 chopper controlled trams in Haizheng with 200 frequency conversion trams and the first domestic polylactic acid demonstration production line with an annual output of 5000 tons. On the actual operation route, the power consumption of various trams was measured respectively

the measurement results show that the power consumption of the new vehicle is 72.6% of that of the resistance control vehicle. According to their calculation of the annual power consumption of 200 new frequency conversion vehicles and 200 old vehicles, the power consumption of the new vehicles is reduced by about 24%. It can be seen that the power saving effect of vehicles using frequency conversion technology is very obvious. Therefore, the Ministry of electronic industry of our country listed the energy-saving technology represented by variable-frequency traction device as the focus of development in the electronic industry as early as the ninth five year plan

China successfully developed AC4000 AC traction electric locomotive in 1996. At present, the power of each traction motor of metro vehicles under DC750V system is 90 ~ 160kW, so the three-point inverter traction system composed of 600 ~ 1000a/1200vibgt can achieve the required capacity. Considering the international advanced level, energy conservation and economic rationality, the transmission scheme of variable frequency speed regulation for three-phase AC asynchronous traction machine was finally determined

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