Control Algorithm for 6 kW Hall Thruster

This paper presents a control algorithm for ensuring the stable operation of a 6 kW Hall thruster. The Japan Aerospace Exploration Agency is developing a “wide-range” power processing unit (PPU) to power a 6 kW Hall thruster system, a candidate for all-electric satellites. The PPU provides discharge oscillation, power, and discharge current control. The increments in the control loop are fixed, so the PPU digital controller does not need to calculate them, and the algorithm's computational complexity is minimal. Results of integration tests on the 6 kW Hall thruster and the PPU breadboard model showed that the three control functions run correctly. The total controlled PPU power was adjusted in the range of 3.45–3.55 kW under constant power control with a target of 3.5 kW. Oscillations of ±0.05 kW around the target power are acceptable. Discharge oscillation control decreased the number of 0.1 ms segments with amplitudes exceeding 1.5 A from 700 to 0 by changing the coil current. The PPU successfully controlled the coil current, reducing the discharge current from 13.7 A to 13 A. The propulsion efficiency increased from 59% to 60.5%.