Driving efficiency improvement of plasma actuator by adjusting applied voltage waveform using a variable reactor

The impact of output voltage waveform variations on the induced flow velocity and driving efficiency of plasma actuators (PAs) was investigated by measuring the velocity distribution, power consumption, and thrust. When PAs were driven using a simple power supply unit with a semiconductor power device, the capacitance of the PA varied with noted differences in the total spanwise overlapped electrode length (Ls) at which dielectric barrier discharge occurred, affecting the induction flow efficiency based on the applied voltage waveform. For a PA with 100 mm spanwise overlapped electrodes, the output voltage waveform could be adjusted from a “bumpy” to a “sinusoidal” form by incorporating a variable reactor. This reactor modified the impedance on the secondary side of the power supply circuit by adjusting the air gap (df) of the EI core, which regulates inductance. Applying a sinusoidal voltage waveform is preferable for efficient PA operation in cases in which a power supply is used in conjunction with a simple electrical circuit. However, even when a slightly distorted waveform was used, such as a “quasi-sine wave,” instead of a pure sinusoidal voltage, the drive efficiency remained largely unaffected. In contrast, waveforms with high-voltage gradients near zero crossings such as “wavy” and “bumpy” led to reduced efficiency.