What is the best topology to make an AC and DC regenerative electronic load?

 

Maybe someone has an idea of what that is, but I do not. Can you explain?

 

What is a regenerative load?

 

A regenerative load is typically used for braking of a motor. In its simplest form its a big resistor able to dissipate 100 or 1000's of watts. That works for both DC motors and AC motors. It can also be used for power supply and battery discharge testing, though more usefully a passive electronic load allows dialling in of a constant current or constant power load. Such loads use multiple parallel MOSFETs running in their linear region (ie as a voltage controlled resistance) with significant cooling capability. Simple, sub 300W, units are easily found on eBay, etc. but units capable of 1000W+ are complex and expensive beasts.

For EV's active regenerative electronic loads allow recharging of the battery when slowing down (regen braking) and/or dumping energy into passive loads when the charge rate exceeds the battery capacity. These systems use a bidirectional inverter DC -> AC-> motor -> AC -> DC topology.

 

An electronic load is fed by an electric outlet. It produces a current to test some other device. But if this device under test is an energy meter, for example, the electronic load would work as a linear amplifier, burning energy in form of heat. Imagine we can return this energy to the outlet instead burn it. This is what I mean by the regenerative electronic load.

 

An electronic load is fed by an electric outlet. It produces a current to test some other device. But if this device under test is an energy meter, for example, the electronic load would work as a linear amplifier, burning energy in form of heat. Imagine we can return this energy to the outlet instead burn it. This is what I mean by the regenerative electronic load.

Exactly so, as given in my last example above.

 

this may be what you are talking about:


The active rectifier acts both as as a full wave rectifier when "motoring" and as as inverter when the motor is "generating" to return energy to the mains supply.

 

this may be what you are talking about:

The active rectifier acts both as as a full wave rectifier when "motoring" and as as inverter when the motor is "generating" to return energy to the mains supply.

That's effectively the EV version, though with a DC feed. Sometimes you see top of the range Variable Frequency Drives (VFD) for machinery (lathes, etc.) do this, though most just use a braking resistor 'cos its cheap.

Also:

 

The resistive braking is AKA Dynamic Braking, as opposed to Regenerative braking. (energy Returned.)

 

That's effectively the EV version, though with a DC feed. Sometimes you see top of the range Variable Frequency Drives (VFD) for machinery (lathes, etc.) do this, though most just use a braking resistor 'cos its cheap.

Also:

View attachment 289801

regenerative braking (in case the mains can take the reverse flow with leading power factor without causing an overvoltage) has been very successfully used in operations like large mineral conveyor belts in mines, lots of energy returned to the grid

 

this may be what you are talking about:
View attachment 289800

The active rectifier acts both as as a full wave rectifier when "motoring" and as as inverter when the motor is "generating" to return energy to the mains supply.

Imagine that I want to test this system you showed. So I would need to simulate the motor. My regenerative electronic load is the motor simulator, but instead transform the energy sent to the motor, my simulator will return it to the outlet.

 

Accurately simulating a "Real" Motor,
operating in a "real-world" practical-application,
is a seriously daunting task.
Not to mention, the very expensive Software required.

What is the SPECIFIC proposed application for this project ?
It may not be even remotely practical.
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.
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in fact, the purpose is to simulate a battery to test a new charger, but instead of burning energy, I would revert it to the outlet.

 

I see.
You need a grid-tie inverter such as Victron's MultiPlus, which you can program to take a certain amount of current from the battery and return it to the grid.
I think that the system will need to have a real battery to keep the system stable but you should be able to make the battery look bigger than it actually is by selecting the amount it returns to the grid.

 

How big a battery?

 

"" but instead of burning energy, I would revert it to the outlet. ""

What does this statement mean ???
Burning Energy where ?, in what device ?, for what purpose ?

Where did the "Energy" come from ?, where does it normally go ?, how is it normally wasted ?
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I see.
You need a grid-tie inverter such as Victron's MultiPlus, which you can program to take a certain amount of current from the battery and return it to the grid.
I think that the system will need to have a real battery to keep the system stable but you should be able to make the battery look bigger than it actually is by selecting the amount it returns to the grid.

Seems like a good first shot to test the idea. But in the future, I need to replace the battery with an electronic alternative. But it show me a way to start, thanks

 

seems a good idea to test the idea, if it works I would change the small battery for a capacitor, and project my own inverter, that will be fast enough to turn possible using that capacitor.

Victron's products are generally far too clever for their own good. You won't fool them into thinking there is a battery when there is a capacitor, but the idea is valid.
If you can find a grid-tie inverter with programmable input current that's not quite so smart you might be on to something.

 

Victron's products are generally far too clever for their own good. You won't fool them into thinking there is a battery when there is a capacitor, but the idea is valid.
If you can find a grid-tie inverter with programmable input current that's not quite so smart you might be on to something.

When I asked this is because I was thinking about making my own inverter to simulate the battery or any other type of load, but my inverter would return the energy to the outlet instead transform it in heat or in movement. But your idea of using a shelf inverter could save me a lot of time.