Battery Management / 3-Phase Motor Control System -
PHASE 1 - Proof of Concept design
Description - Electronics to integrate the following components
33 (thirty three) 3.7 Volt, 10AH lithium-polymer battery cells (Each individual cell already contains circuitry to protect from overcharge/undercharge.) Battery Specifications attached.
45 (forty-five) 2.7 Volt, 2200Farad (yes, 2200 Farad) Capacitors. Capacitor Specifications attached.
2 (two) 3-phase, 120 Volt electric motors
1 (one) Foot-Activated speed-varying Potentiometer
1 (one) Foot-Activated variable motor brake (electrical regeneration)
2 (two) DC Generators (brakes) as chargers
1 (one) Generator Charger ac/dc
1 (one) 120V AC Charger – Household Plug
It is important to understand, most of these items are available off-the-shelf individually. The use of existing hardware / technology is not discouraged.
This will eventually be a drive system for an electric car. All systems must be monitor able by a windows-based program, all variables discussed must be programmable and user selectable via said program.
The main power for the system will be the 33 battery cells, combined to make 120 volts. Primary method of charging will be via 120V AC charger w/ household plug. Each individual cell already contains over/under load protection. Ability to monitor individual cell status, as well as entire pack status with instrumentation output leads required.
The 45 capacitors need circuitry designed to evenly charge. Capacitors are needed due to motors drawing more amps than batteries alone can provide. Capacitors will charge from both the battery bank and regeneration of electricity occurring upon activation of the variable motor brake. Capacitor charging limit (% of capacity) must be programmable. (ie 70% - if they are over 70%, excess is dumped back to batteries. This is due to capacitors being needed for regenerative braking – there always must be a buffer)
Motor Speed control, using speed potentiometer – as this is for the propulsion of an electric car, motors must be speed-controllable. There are many AC speed controls already on the market – however, this must be two-channel (two motors). See [url removed, login to view] for a good start. NOTE: Controlled amperage draw is VERY high. This is a weakness in all motor controller systems. Must be made to handle 2 X max motor draw. Controller must control motor speed, handle amps, also handle the charge of the capacitors from the REGEN braking, plus interface with the programming of the parameters.
Foot activated motor brake / potentiometer – Stepping on “brake” pedal flips drive motors into generator mode. Further the pedal is pressed, more they should feed the batteries, slowing the vehicle as well as recharging the batteries thru the capacitors. In addition, two generators (one per motor) are connected via magnetic particle coupling to assist in braking.
If speed control of motors must be separate from the battery/capacitor/generation array, that is fine – explain why.
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