Time-domain Characteristics of the Audible Noise Generated by Single Corona Source under Positive Voltage

This paper aims to investigate time-domain characteristics of the audible noise caused by single corona source under positive corona discharge. The obtained time-domain waveform of the audible noise consisted of a series of bipolar sound pressure pulses. After the background noise was successfully removed, the characteristics of audible noise pulses, such as amplitudes of each pulse, pulse rate and apparent duration time, were analyzed in this paper. Using the applied voltage and the onset voltage as variables, empirical formulas were derived from the measured results to predict the pulse rate and the amplitudes of the pulses. Furthermore, a typical waveform in the form of segmented double exponential function was developed to simulate the audible noise pulse. The rationality of the typical waveform was confirmed both in time domain and in frequency domain. Finally, some qualitative explanations for the generation of the bipolar pulse waveform of audible noise were given. Based on the remaining space charges characteristics, the influences of the applied voltage on the amplitude and pulse rate of the audible noise pulses were studied qualitatively.