Hi, i have a small 1.5kW wind turbine which i have hooked up to an turbine protection box. It converts 3 phase wild AC into DC with the addition of a dump load output for grid failures and over speeding.

The box is designed to stop the DC voltage of the turbine going above 600v, protecting the grid tie inverter as this unit has a max of 600v. This is achieved with an IGBT which switches a 3kW dump load resistor on at 515-530v.

This is all working as it should, however i am looking to change my grid tie inverter to a unit which can only receive a max of 500v instead of 600v. I am looking for an IGBT which can switch on the dump load at 400v instead of 500v. I don't have the part number for the IGBT fitted currently but i will get that soon and amend this post.

Any help would be appreciated, i have looked online at various parts but with my limited knowledge of electronics i am struggling to find a solution.

Thanks to anyone who reads this post.

B. Williamson

 

A 500 volt switch should be able to handle a lower voltage and probably be more reliable in the that situation. Just be careful to not exceed the switch's current rating.

 

A 500 volt switch should be able to handle a lower voltage and probably be more reliable in the that situation. Just be careful to not exceed the switch's current rating.

Any ideas how I’d get it to switch at a lower voltage?

 

Its not the IGBT that determines the switch point, its the circuit that controls the voltage on the gate. Somewhere there'll be way of comparing the DC voltage with a reference voltage. That may already be adjustable, or can be modified. We'll need some photos of the control board that drives the IGBT.

 

Its not the IGBT that determines the switch point, its the circuit that controls the voltage on the gate. Somewhere there'll be way of comparing the DC voltage with a reference voltage. That may already be adjustable, or can be modified. We'll need some photos of the control board that drives the IGBT.

Ok, no problem I will get some photos tomorrow.

thanks very much for your help

 

There is a white wire which looks like it comes from the DC + up to the top and goes through a series of components and then to the top right connection on the IGBT pictured first.

Thanks

 

I have just found this diagram. I must need to change something about the 'Control' which effects the IGBT switching point