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Abstract - A six-phase 12 pulse passive converter is to be designed for a high speed permanent magnet synchronous generator which is driven by a gas turbine engine at a speed of 30,000 rpm.In this project the output voltage is maintained at a constant value of 28 volts with respect to change in the input voltage this is achieved by a novel rectifier topology, which are formed by combining the passive 12-pulse rectifier with a boost stage on the DC side are proposed. This allows to guarantee a constant output voltage and or to overcome the problem of the dependency of output voltage on the mains voltage amplitude and output power level.
Keywords: Six-phase, 12 pulse converter, DC-DC converter
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I. INTRODUCTION
The design of six phase twelve pulse converter for permanent magnet synchronous generator is a new and basic concept of design solution in application of high speed machines. Accordingly, there is a growing interest in the industry in technology to ensure that the subsystems are ultrareliable, easy to maintain, low in cost and of high performance. As one essential part of the power distribution systems, AC/DC converters, which are connected to a variable frequency AC bus are employed for supplying power to all kinds of DC loads. Such systems are required to show low volume, high reliability, ability to carry over current and low input current harmonics.
Passive converter systems with approximately sinusoidal input currents like the 12-pulse rectifier are typically used in mid- and high-power applications. Such passive systems do not require control electronics and are therefore characterized by a very low realization effort and high reliability. However, the required mains frequency magnetic components result in a low power density and high system weight. The input frequency of the converter is 500Hz, therefore the size of the magnetic components of 12-pulse rectifiers can be significantly reduced as compared to a 50Hz mains operation. Furthermore, it will be shown how to actively control the DC output voltage of the 12-pulse converter by simply adding a turn-offpower semiconductor and a power diode on the DC side resembling a boost stage. This approach results in a significant improvement of the functionality of the converter system.
II. PASSIVE 12-PULSE RECTIFIER
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