DSP-based current control for inverter-fed permanent-magnet electrodynamic shaker

Compared to the conventional analog-circuit control and linear power amplifier for permanent-magnet electrodynamic shaker (PMEDS), a DSP-based digital current control with switched-mode power amplifier is proposed in this paper. A full-bridge converter is connected directly to PMEDS without LC filter in order to directly regulate the shaker current and simplify the digital current control. To meet the vibration requirement of wide operating range (typically 5~2 kHz), the frequency of the unipolar switching scheme is increased to 50 kHz PWM frequency in order to reduce the aliasing effect of the induced voltage and current harmonic sidebands. At the same time, dead-time compensation loop is also included in the digital current control to decrease the harmonics due to the dead-time in gate signals. The effectiveness of the proposed current control is verified by the provided simulation and measured results.