Hybrid Speed Control of a DC Motor for Magnetic Wireless Manipulation Based on Low Power Consumption: Application to a Magnetic Wireless Blood Pump

This paper presents the magnetic properties and hybrid speed controls for low power consumption of a portable external driver based on a dc motor with a magnet to drive a magnetic wireless blood pump. Within a portable system, having low power consumption is the most important factor. In this paper, we propose a hybrid control method using the pulse width modulation (PWM) and the variable electromagnetic-load method (VEML) to extend the driving time of a rechargeable battery. The VEML method plays the role of a variable mechanical load. To reduce overall power consumption, the PWM and VEML methods were used at low and high rotations per minute, respectively. Hybrid-control of the VEML and PWM methods resulted in power consumption reduction of up to 67.52%. For the wireless operation, the external driver allowed a synchronous radial coupling. Moreover, the VEML structure, which acted as a magnetic power generator, produced the electrical power. The observed ac signal from VEML was used to check rotations per minute without having to use a motor encoder. The proposed external driver consisted of a dc-motor, Nd–Fe–B type of cylindrical permanent magnet, a wound coil, a variable resistor, and a PWM driver. In addition, we investigated the magnetic characteristics of the driver through various simulations and experiments.