Looking for suggestions on how to approach switching power to a series of EM Coils along a rail (EM Launcher)

[EHTDesigner]

I'm going to do a search on this question as I've seen some similar questions answered.

I'm starting a project that I've seen videos of and would like to make some changes to it for my purposes. It's an Electromagnetic Launcher. A photo of one of the coils is below. Let's say there would be 10 of these coils along a rail. There's a hall effect sensor that turns on a MOSFET energizing the coil when a magnet comes close to the hall effect sensor. The result is the field of the coil will pull the magnet towards the coil's center propelling the magnet forward. However once the magnet reaches the other side of the coil, the field present will pull the magnet back to the center of the coil, thus stopping the magnet from moving forward. What suggestions do you have to reverse the polarity to the coil when the magnet reaches the center of the coil? I was considering an H-Bridge but cant quite see how to use that in conjunction with the MOSFET. If I have 10 coils in a row, do I need 10 separate circuits or can there be a way to turn on power to the other coils. Power is on to the coil only when the magnet passes the hall effect sensors

 

[Diver300]

An H-bridge is usually 4 MOSFETs. Two are tuned on to energise the load in one direction, the other two are turned on to energise the load in the other direction.

You will need 10 circuits.

You will probably need to have H-bridges to reverse the current quickly. You will also need large voltages to start and stop the current quickly.

It may be possible to have only 6 H-bridges to run 10 coils if you only need to run one at a time. Here is how three motors can be run from two H-bridges, and that idea can be extended.

(That is from the data sheet of a VNH5019A-E if you want to know more. The extra MOSFET is for reverse polarity protection)

The first H-bridge can run one load in either direction, and each additional H-bridge adds two more loads. So 6 H-bridges could run 11 loads in either direction if you only ever needed to run one at a time.