I am inquiring about using three Victron MultiPlus-II 48/5000 inverters (three-phase system ) for handling regenerative energy from lifts . The energy generated by each lift during braking is in the form of AC power. I would like to know if these inverters can efficiently manage the regenerative energy in a three-phase setup.
Could you please confirm whether any additional components, such as rectifiers for converting AC to DC, are required? Also, are there any limitations or specific configurations needed to integrate the regenerative energy from the lifts into this system?
I think that the alternating current is simply “burned up” via braking resistors. A kind of retarder brake.
You will not be able to use this energy because the elevator will not brake.
Also, the voltage and frequency will not match.
Victron inverter/chargers do allow devices like PV inverters to feed energy into the AC output. This energy is either fed to the grid or to the batteries assuming they are not fully charged at the time.
Like many inverters, the Multi/Quattro will increase the frequency of the output when off grid and the batteries can not accept any more power. Any device that feeds energy into them must do similar things or monitor battery SOC and not feed energy to the inverter. This means that you’d need something else to absorb the breaking energy when the batteries are full.
Your comment is valid in traditional systems where the energy from regenerative braking in elevators is indeed dissipated as heat through braking resistors. This process, often referred to as a dynamic braking system, converts excess electrical energy into thermal energy, which prevents the elevator from accelerating uncontrollably. However, in regenerative systems, the situation is different.
In a regenerative braking system, rather than “burning up” the energy via resistors, the energy is captured and reused. This system converts the kinetic energy generated during braking back into electrical energy, which can be fed back into the building’s electrical system or stored in batteries for later use.
Interesting
BUT how is the mechanical energy converted? A generator must be coupled in, otherwise you wouldn’t be able to tap any AC voltage.
Or does the motor become the generator?
A drawing or diagram would be helpful.
This energy could potentially be used by other devices in the house if there is a demand at that moment.
My main curiosity is what happens if the inverter is already working at around 70% of its capacity from the battery and suddenly receives energy back via the same AC output cable?
In a regenerative braking system, the motor itself becomes a generator when the lift is braking or moving downward with a load. This happens because the kinetic energy from the moving elevator is converted back into electrical energy. The same motor that powers the lift also switches to generator mode during braking, producing alternating current (AC) instead of consuming it. This AC energy can then be fed back into the building’s electrical system or used for other purposes, like charging batteries.
Here’s a simplified explanation of the process:
Motor as a generator: When the lift slows down, the motor’s role reverses. The mechanical energy of the elevator (moving due to gravity) turns the motor, which now generates electricity rather than consuming it.
AC voltage generation: As the motor spins in reverse, it generates AC voltage, which is either used directly or converted into DC for storage.
Is the whole thing just an idea or does such a system already exist?
I can’t imagine simply running a motor as a generator and simply “feeding back” this energy.
The speed and frequency can’t match, depending on how heavy the lift is …
I could imagine using a “relatively” fast frequency converter. Different frequencies and voltages could then be used.
The elevator has been operating with regenerative braking for the past 4 years, successfully feeding the recovered energy back into the building’s internal electrical system. It works by converting mechanical energy from the braking process into usable electrical energy, which powers other devices in the building.
At the moment, I’m exploring options for integrating backup power into the system, and there’s concern about how this regenerative energy might interact with inverters. The regenerative energy could potentially cause issues if not properly managed, particularly in situations where the inverter is handling both backup power and the returning energy.
So, while the system is already functional, my focus now is ensuring that there are no complications with the inverters when both regenerative and backup energy are in play.
please elaborate what happens when the grid connection to the building fails?
The way you describe the functionality of the system without backup power implies that the regenerative braking system would stop working in that case, wouldn’t it?