Design and thermal assessment of a micro electromagnetic actuator

Abstract : In this paper, an experimental study to investigate maximum drive current handling capability of a compact electromagnetic actuator is presented. The actuator design consists of a mobile part and a fixed part. The mobile part assembles two pairs of six permanent magnets into a small cross structure. The fixed part integrates two planar electric drive coils. These coils are isolated from each other and are fabricated into top and second layer of a four layer printed circuit board. In addition, to reduce the overall temperature of the fixed part, a thermal pad has been integrated. During experimentation, the actuator was injected with different amplitude of sinusoidal currents, to drive the mobile micro pallet onto the fixed part. A thermal sensor is used to measure the surface temperature rise due to joule heating. From experimental results, it has been concluded that the proposed actuator design can handle upto 0.8 A of sinusoidal current with a maximum rise in surface temperature of 48°C in 100 cycles test of 8 mm along both x-and y-axis. The maximum cooling time was found to be 450 seconds.