What is a Moving Magnet Voice Coil Actuator?
A Moving Magnet Voice Coil Actuator (MMVCA) is a linear single phase actuator that consists of a magnet assembly attached to the load and a coil assembly connected to the static world. MMVCAs are mostly marketed as low cost pneumatic cylinder replacements. It is comparable to the more conventional Moving Coil Voice Coil Actuator (MCVCA) with respect to functionality and force levels.
Moving magnet vs moving coil
MMVCA excels over the MCVCA with respect to durability, efficiency and achievable stroke length. This is due to the fact that the coil is static, which results in no moving wires and thus increasing durability. Moreover it creates a better thermal path as heat is generated on the outside static part. It also makes it possible to apply active (water)cooling, which allows for much higher force density.
In addition, the moving magnet technology lacks any mechanical gear or other reduction. It transfers force to the magnet assembly only by means of the magnetic field generated by the coil assembly. Therefore, the MMVCA accomplishes zero mechanical wear, backlash, or mechanical friction leading to potential particle generation.
Advantages of a Moving Magnet Voice Coil Actuator
In general, the technology utilizes only a single electrical phase to control the force and position of the magnet assembly. So, it is not needed to utilize a position measurement system for controlling and driving the current. As a result, driving a moving magnet actuator is similar to driving a linear BLDC motor. This way, the MMVCA reduces system cost, improves robustness, and reduces control complexity. Other advantages are:
• Cost optimized solution
• Easy to use