Analysis of Output Voltage Power Spectrum of High Voltage Power Supply

Nouri Jevinani, Hadi | 2021

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 54326 (05)
  4. University: Sharif University of Technology
  5. Department: Electrical Engineering
  6. Advisor(s): Kaboli, Shahriyar
  7. Abstract:
  8. Some microwave tubes can function as a narrowband power amplifier and their output power spectrum is an indicator of their amplification and efficiency. One of the factors affecting its power spectrum is the noise and ripple of its HVDC power supply. To reduce the negative effects of power supply, first there should be an exact measurement of ripple and noise in the output of the HVDC power supply. Destructive factors which affect voltage ripple measurement in the case of high DC voltage are follows as conductive interference, radiative interference, intrinsic noise of electrical elements, and nonideal frequency response of voltage divider. After identifying and suppressing the mentioned destructive factors, there is conventionally a high-pass filter to filter noise at the last stage of ripple measurement. This filtering technique does not distinguish between power supply noise and measurement noise and attenuates both, so it is not a good way to measure the output noise level of the power supply. Also, a high-pass filter would attenuate all the frequency components or ripple components at the output of the power supply, excep those which are before the filter's corner frequency. The proposed measurement technique in this Thesis utilizes dual-channel measurement based on calculating the cross power spectrum of the two identical measurement channels. In this way, uncorrelated measurement noises will reduce, but the input ripple and noise of the power supply will not. In the next chapters the mathematical theory and formulation behind the mentioned technique is discussed and along with simulations and practical test, the functionality of it has been verified in comparsion to a one-channel measurement and using a high-pass filter
  9. Keywords:
  10. Power Supply ; Microwave Tubes ; High Voltage Power Supply ; Ripple ; Noise ; Signal Spectrum ; Spectral Analysis

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