Energy-Based Analysis and Predictive Variable Frequency Control Scheme of a High-Voltage Solid State Pulse Generator for Space Applications

Pulsed plasma thrusters (PPT) hold significant promise for space exploration and exploitation by integrating high-power capabilities of magneto-plasmadynamic (MPD) thrusters with low average power consumption (typically $< $150 W) and reduced heat generation. These thrusters are powered by high-voltage pulse generator with peak pulse magnitude ranging from 250 V to 2.5 kV. Pulse generators in the literature often exhibit longer charging times, which limit the pulse repetitive rate (PRR) to below 500 pulses per second and prevent it from achieving the desired pulse voltage profile. This article proposes a resonant-based high-voltage pulse generator that features programmability for pulse amplitude, enhanced PRR, reduced full width at half maximum (FWHM), and improved efficiency, addressing the requirements of the PPT. A predictive control scheme is proposed for the variable frequency-based high-voltage pulse generator, eliminating the need for current and voltage sensors; reducing system costs, associated conduction losses, and control complexity compared to conventional control methods. An energy-based analysis is used to investigate the impact of parasitics in the pulse generator deriving essential parameters for PPT operation and offering an improved analytical approach. The energy-based analysis, derived analytical expressions and proposed control scheme are validated through experimental testing for pulse voltage of $-$2.5 kV, with a PRR of 1000 Hz and a FWHM of 20 $\mu$s. The proposed control scheme achieves precise tracking of the mosfet turn-on and turn-off instants, reducing timing errors to less than 5% compared to conventional control methods.