How do i use a rectifier

Problems with efficiency and heat in a rectifier

Reverse recovery of your diodes will affect the power dissipation in your application, but in this case it is extremely unlikely to be the main cause of performance / efficiency degradation. You can start by comparing a fast rectifier to your current rectifier. The VUO52-16NO1 and a much faster VUE130-12NO7 make a good comparison.

While you get lower switching losses in the VUE130, the power loss is actually dominated by the difference in Vf in your application (which I assume is a vehicle alternator). The VUO52- has a Vf of only 1.4 V for a total bridge loss of approximately 160 W at 60 A and the VUE130- has a Vf of 2.7 V for a total loss of approximately 320 W at 60 A. The recovery losses for Es is unlikely the VUO52- will be more than about 16W. Since you have a large output filter capacitor, the diodes will go into reverse recovery immediately after the peak of each phase voltage. Yes there is reverse current flow but it is compared to If max, this might be worth reading for you.

You can use fast and low Vf Schottky diodes to reduce the voltage drop. For example, the APT60S20B or the VS-100BGQ100 (better suited as it can be bolted on) would mean more than half of your power outage.

The best way to reduce both switching and forward power dissipation would of course be to use a half or full synchronous rectifier. More complex electronics, but power losses in the rectifier can be reduced to a few watts with full synchronicity.

SMART and synch rectifiers

If you are looking for SMART rectifier controls (like this one) you will see opportunities to use FETs as ideal rectifiers. There are a lot of these controllers out there, but be sure to understand that some of these devices only operate at low frequencies and therefore may not be suitable.

An easy way to implement synchronous rectification is to sense the current in the bottom diode of each pair and use an FET on the top diode. It's easy and cuts your performance loss in half. You can implement this with the 3 phase rectifier already in place.

Then you can get creative and create your own microprocessor solution. However, if you are not at this level, you can use an open source ESC controller as a synchronous rectifier. Here is a demo of it on YouTube. Here the user just uses the ESC32 as is, but you can change the speed automatically by changing the firmware. Again, this depends on your skills.


Thanks Jack. The generator is a 3-phase permanent magnet RC motor. I have low voltage and high current, so yes, bridge rectifier has big losses because of the forward voltage in the diodes. Ok, maybe the VS-100BGQ100 can reduce both losses: 0'82 Vf (at 100A) and 45 ns reverse recovery time. On the other hand, I think synchronous rectifiers are still in development. I don't know if I can find a commercial one for my functions. I see Texas Instruments have a controller for MOSFET, for example, but I'm not sure if it's down to earth for me.

Jack Creasey

The reverse recovery losses are insignificant. You will not change your total electricity consumption by more than one percent. Choose a low Vf Schottky diode and ignore the Trr. The VS-100BGQ100 I recommend seems like the best choice that will get you around 100W losses at 60A. Synchronization rectification is well established and understood, but usually complex. I've seen some very creative ways to implement it. I will look for references and post on the answer.


Jack, I was looking for the topics you wrote. I will start trying VS-100BGQ100 Schottky Diodes as I now need to run the system and manage it. At the same time, I will continue to look for synchronous rectification and also for ESC in order to improve the efficiency of the system in the next step. Thanks for your help!