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Discussion Starter #1

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What do you want to drive with this?

These controllers/motor drivers are for Brushed DC motors. So just advanced PWM drivers.
 

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Discussion Starter #4
I want to start with experimenting on a (Series) DC motor.
To play with I have a small boat with a 48V system, I currently has a Kelly controller (after the Alltrax died which replaced a Kelly...)

I know this system is better of / cheaper with an off the shelf controller but it is something I have available and can pull some amps with.

Later on if I manage to work things out without big explosions, I want to move up to a HV system in another boat I have.

I have some broken down (at the moment a 150A and a 300A) industrial VFD's with good IGBT's, capacitors, etc.
Everything with a good layout, bussbars, cooling, casing, etc so a nice start for someone as lazy as me (lots of steelwork to do on my boat so this is a 'spare time in spare time' project)

I really like the work of Johannes Huebner on the AC controller but I think I better practice with one IGBT at a time first ;)
 

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For your application, what is wrong with using vfd for motor control? Or is the water just a energy dump for testing so you will end up designing for a vehicle?
 

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Discussion Starter #8
For your application, what is wrong with using vfd for motor control? Or is the water just a energy dump for testing so you will end up designing for a vehicle?
It's a DC motor and VFD is for AC motors.

This is one of the vfd's I have ([email protected]):


AC-DC, Driver board, I think the red-brown square block beside the screwdriver is one of two snubber caps, I don't have a close-up of them.


Driver board and buss-bars removed


Left to right: AC-DC, Shunt for motor leads, IGBT's, DC-bus capacitors


4 of these relays are between the capacitor bank (capacitors are 2s4p), dont know yet how exactly they work.


The IGBT's (300A / 1200V)


The shunt.

I hope to find the circuit diagrams so it's easier to reuse (parts of) the driver boards
 

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wouldn't mind finding one of those to mess with. Can you zoom in on the area where the gates plug in? Trying to identify the gate driver details a bit. Also is there an obvious microcontroller somewhere with a part number? With a prop load you might be able to get away with a simple pwm scheme and just watch the ammeter as you roll on the throttle. I assume there are fans and a heatsink yet buried?
 

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The control logic is really quite simple for a dc motor controller.
The problem is always the power stage blowing up and can blow up the control board too.
There are IGBT driver boards you can buy, like the VLA504
and then just connected up a 5v pwm signal from a micro.

It is all simple in theory, in practice it is countless hours of tinkering.
You will need a scope to check your progress or lack thereof.

My first EV motor controller was from IGBT modules and I drove my hybrid project car using one I made.

Just be sure you understand how much time it will take, even at $1/hour, buying a 48v controller is 100 times cheaper. So sure then you will learn a lot and can build other things later, if that is what interests you.
 

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@boekel I looked at a couple of your projects, it is impressive. It seems like you are moving away from a 3 phase genset and towards a battery perhaps?

If ultimately you want to control your AC motor (instead of the series motor), you may be able to connect DC battery to the input of the vfd (or the DC bus) without any other changes. It is a pretty big maybe, with the shunt and other leads near the input though, I have zero firsthand experience here.

http://www.practicalmachinist.com/vb/transformers-phase-converters-vfd/vfd-dc-input-102201/
 

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Discussion Starter #12
wouldn't mind finding one of those to mess with. Can you zoom in on the area where the gates plug in? Trying to identify the gate driver details a bit. Also is there an obvious microcontroller somewhere with a part number? With a prop load you might be able to get away with a simple pwm scheme and just watch the ammeter as you roll on the throttle. I assume there are fans and a heatsink yet buried?
Jup, power electronics are mounted on the heatsink, the DC-bus capacitors are first 'in the wind' then the heatsink.




This are the driver circuits on the 37kW unit (it has two 6MBI75S-120 6in1 IGBT modules paralleled)
I havent found where they get dc-supply from yet


The feedback circuit from the shunts.


Powerboard from the 37kW units, shunts on the left.


complete driver board, no MCU in sight!


I think the computing power is in this IO module!

 

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Discussion Starter #13
The control logic is really quite simple for a dc motor controller.
The problem is always the power stage blowing up and can blow up the control board too.
There are IGBT driver boards you can buy, like the VLA504
and then just connected up a 5v pwm signal from a micro.

It is all simple in theory, in practice it is countless hours of tinkering.
You will need a scope to check your progress or lack thereof.

My first EV motor controller was from IGBT modules and I drove my hybrid project car using one I made.

Just be sure you understand how much time it will take, even at $1/hour, buying a 48v controller is 100 times cheaper. So sure then you will learn a lot and can build other things later, if that is what interests you.
I'm hoping to learn what part of protection is best incorporate in the driver-ic and what part in the controller. this pdf is a nice read:
http://www.st.com/web/en/resource/technical/document/datasheet/CD00047616.pdf

Lots of igbt-drivers to choose from, hope some people can name their favorites and why to choose that one.

I know for the 48v system an of the shelf (mosfet based) item is a better and cheaper solution, I even have a spare controller (Altrax spm) in case the Kelly stops working ;)

@boekel I looked at a couple of your projects, it is impressive. It seems like you are moving away from a 3 phase genset and towards a battery perhaps?

If ultimately you want to control your AC motor (instead of the series motor), you may be able to connect DC battery to the input of the vfd (or the DC bus) without any other changes. It is a pretty big maybe, with the shunt and other leads near the input though, I have zero firsthand experience here.

http://www.practicalmachinist.com/vb/transformers-phase-converters-vfd/vfd-dc-input-102201/
Thanks.
For my 'big' boat I'm moving from diesel-electric to serial hybrid, I have to siemens / dmoc645 sets for that.

Industrial vfd's can be fed with DC, only not all are working with the lower voltage I want to use (300-400VDC range), the ABB drive I have doesn't like lower voltages.

The DC controller could probably be fed with a simple pwm signal, as it doesn't need high torque starts and things alike, overcurrent and short circuit protection could be in the igbt-driver arrangement then. Only time high peaks can occur is during fwd/rear switching.

On a AC-drive V/Hz control is quite perfect for all use except direction changes. You don't want torque mode in a boat, except during direction changes.

This 'DIY controller project' of me won't be going fast as the steelwork on the boat has priority, but I hope to try and learn some things this winter :)
 

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Ah ok, re: gate drivers, johannes has published the schematic for his in the zip file here , which is a fairly common approach http://johanneshuebner.com/quickcms/index.html?en_downloads,14.html

it is in the pcb directory, using eagle cadsoft (free).

You only need 1/2 of 1 (and half of one of those IGBTs) to drive a series motor, I assume you know series motors can't be run unloaded (at least not without rpm feedback and limits).

If ultimately you are moving in the direction of his three phase controller then you might want to look into an olimex h103 as an MCU and the other circuits he uses for pack sensing and current sensing and rpm feedback (and throttle, etc).

Heck you might want to order a whole kit and just modify the program to be a series controller or an ac controller and leave your power section largely intact (assuming there is room for it on the boat).
 

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Discussion Starter #15
Ah ok, re: gate drivers, johannes has published the schematic for his in the zip file here , which is a fairly common approach http://johanneshuebner.com/quickcms/index.html?en_downloads,14.html

it is in the pcb directory, using eagle cadsoft (free).
Thanks!
Very easy schematic, no desaturation detection in the driver, haven't read enough of his topic to know if that is done deliberately though

Heck you might want to order a whole kit and just modify the program to be a series controller or an ac controller and leave your power section largely intact (assuming there is room for it on the boat).
It's three DC-controllers in one :p
I'm no programming hero...did a lot of electro-stuff when I was a kid, now slowly picking up again. I'm a Mechanical Engineer rather than EE / Programmer so will try to start as simple as possible (like hardware current limiting, arduino as control logic, etc.
 

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It may be worthwhile to look at some of the posts in the DIY 10/12 kW charger thread for ideas on driving IGBTs and using PWM. Much of the circuitry is similar to that of a DC motor controller, and you may want to consider the PFC boost circuit for stepping up your 300-400V battery to 400-500 VDC which should make most 480 VAC VFDs happy. You don't really need PFC for a DC battery source, but the design works about the same as a simple DC-DC boost.

You may also be able to use some of the Arduino firmware to interface to a display and use its PWM functions. I am more experienced with PICs but the Arduino may be more easily available and there are many support forums and "shields" that can jump-start a project.

Good luck! :)
 

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Discussion Starter #17
It may be worthwhile to look at some of the posts in the DIY 10/12 kW charger thread for ideas on driving IGBTs and using PWM. Much of the circuitry is similar to that of a DC motor controller, and you may want to consider the PFC boost circuit for stepping up your 300-400V battery to 400-500 VDC which should make most 480 VAC VFDs happy. You don't really need PFC for a DC battery source, but the design works about the same as a simple DC-DC boost.

You may also be able to use some of the Arduino firmware to interface to a display and use its PWM functions. I am more experienced with PICs but the Arduino may be more easily available and there are many support forums and "shields" that can jump-start a project.

Good luck! :)
Thanks! I downloaded the schematics.
A DC-DC (boost) converter is something I hope to avoid, at least for high-power applications.
 

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The control logic is really quite simple for a dc motor controller.
The problem is always the power stage blowing up and can blow up the control board too.
There are IGBT driver boards you can buy, like the VLA504
and then just connected up a 5v pwm signal from a micro.

It is all simple in theory, in practice it is countless hours of tinkering.
You will need a scope to check your progress or lack thereof.

My first EV motor controller was from IGBT modules and I drove my hybrid project car using one I made.

Just be sure you understand how much time it will take, even at $1/hour, buying a 48v controller is 100 times cheaper. So sure then you will learn a lot and can build other things later, if that is what interests you.
 
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