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INFLUENCE OF THE CONTROL PRINCIPLE ON A HIGH-VOLTAGE INVERTER SYSTEM FOR REDUCTION OF TRACTION-TRANSFORMER WEIGHT
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| Author(s) |
S. Östlund |
| Abstract |
In electric traction vehicles with 16 2/3 Hz supply voltage the transformer adds considerably to the total weight of the vehicle. By chopping the supply voltage, the transformer can be designed for a higher frequency resulting in a smaller transformer with reduced weight and losses. The influence of two different control principles on the transformer design and operation of a naturally commutated high-voltage inverter system has been examined. If the frequency is constant the transformer is not fully utilized and weight and losses are higher than when the transformer frequency is allowed to vary. A limitation of the transformer flux provides a frequency that varies between values higher and lower than the average frequency. On the other hand a variable frequency system generates more unfavourable line current harmonics. The weight of the system has been calculated for different operation conditions and frequencies. At 200 Hz transformer frequency constant frequency operation reduces the weight of the supply system compared to a normal 16 2/3 Hz transformer by 32 %. That is about 3.5 tonnes for a 5 MVA system. At variable frequency operation the weight is reduced by 37 %, that is about 4 tonnes. |
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| Filesize: | 607.1 KB |
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| Type |
Members Only |
| Date |
Last modified 2021-02-23 by System |
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