LERS: Lightweight Energy Recovery System

Finally got some time to write my findings down. Not being able to invent and deploy an energy recovery system onto VeC 2.0 has always been a pity. I was genuinely bad at electric system design (even now), but I’ve spent some time studying ECE. I noticed that there’s something called exciter generators. I don’t think I need to introduce the working principle here. Basically, it’s just replacing the permanent magnet in the normal brushless generators with an electromagnet driven by an external voltage.

However, the bigger problem that I want to address here is the market. I found that this type of generator is highly dedicated to the automobile industry. I could barely find any consumer-grade generators on the market. The one shown in the picture attached above is the only available one. It has two options in power: 1 kW or 1.5 kW in either 14 V or 28 V, both of which do not meet the voltage requirement of VeC 2.0. To use it to charge the 12 V battery we have, we will need to apply an AC-DC buck converter.

Here comes another problem: we cannot afford the cost, mechanically, to have drive train that has a detachable branch connected to the motor (so that it does not absorb kinetic energy in regen mode) and a detachable branch going to the generator (so that it does not absorb kinetic energy in driving mode), as it will be large, complicated, and heavy. That means we need the generator also work as a motor. This is possible, just that it requires the AC-DC buck converter to be invertible, which is not possible.

In addition, the power is another problem. 1.5 kW is not enough to power a fast EV.

Therefore, we still need further exploration on this path, but at least we know how to control the braking power.