Objective: This paper introduces a comparable optimized PWM ML4428 control chip, which provides all the functions necessary for controlling a Blood Pump. The Blood Pump is based on an Active magnetic Bearing (AMB) system. Methodology: Directing to the dual-loop speed control system in the chip, which has a confined range of speed-modulate voltage, A speed-modulate design is introduced for the purpose of allowing off-range modulate voltages to work. This module serves a function that can transform the off-range modulate voltage into within-range modulate voltage through a digital electrical network as an AD converter to implement PWM.
Conclusion: and Discussion Based on this module, we made experiments to test rev of the Blood Pump under the condition of invariable control voltage and invariable inlet pressure respectively. The result shows, with inlet pressure of 22mmHg and control voltage of 22V, the rev of pump can be up to 8000rpm, outlet pressure with 100mmHg, and flux with 5L/min. The result meets our initial expectation.