Seeking Assistance in Selecting a Motor for a Single-Phase Inverter Roadtest

8 Sep 2021

I'm getting ready to launch a roadtest on a 70 W Single-Phase Inverter Using BridgeSwitch for Fan Application. I was sent the board, but I wanted to send a motor with the inverter board.

I'd like to get some help in selected a compatible motor. Here's the info on the board, as well as some relevant links.

Here are some key features:

• BridgeSwitch – High-voltage half-bridge motor driver

• Integrated 600 V FREDFETs with ultra-soft, fast recovery diodes

• Inverter efficiency up to 97% using block commutation scheme

• Less than 60 °C package temperature at 29 °C ambient with no external heat sink

• Fully self-biased operation – no auxiliary power supply needed

• Supports low-side external bias operation for low no-load input power

• Integrated high-side and low-side cycle-by-cycle current limit on each BridgeSwitch device

• Instantaneous phase current information output on each BridgeSwitch device

• High-voltage DC bus monitoring with four undervoltage and one overvoltage thresholds

• Two-level device over-temperature protection

• Single-wire status update communication bus

Here are some links:

https://uk.farnell.com/power-integrations/rdk-872/ref-design-board-1-phase-bldc/dp/3755109

https://www.farnell.com/datasheets/3208967.pdf

https://www.power.com/design-support/design-kits/rdk-872-reference-design-kit

If you could send me some suggestions for motors to go along with this board, I'd appreciate it.

Randall

--element14

Top Comments

rsjawale24 over 3 years ago in reply to geralds

I couldn't find them on the ebmpapst website. Also, are these brushless motors?
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geralds over 3 years ago

Hi Randall rscasny ,

in the design manual, they used the fan motor from EBM-Papst:
NRG118/0800-3612 EC
https://www.heiz24.de/media/image/product/328577/lg/ebm-nrg1180800-3612-031111-55667-30431-geblaese-neu.jpg
https://www.heiz24.de/media/image/product/328577/lg/ebm-nrg1180800-3612-031111-55667-30431-geblaese-neu~2.jpg

Datasheet
5566731260-NRG118-0800-3612-030204-CVI.pdf (ebmpapst-ventilator.hu)

Power-Int design manual:
https://www.power.com/sites/default/files/documents/rdr-872_70watt_1-phase_inverter_using_bridgeswitch_for_fan.pdf
Page 36 - image and table 6; "Test bench details"
But this motor has a hug inrush current, it is an 80 W motor ( I nominal 0,0125A) . Is this motor right what mentioned in the manual? hm...
bridgeswitch_family_datasheet.pdf (power.com)

My suggestion for the first:
Produkt-Datenblatt 7450ES (ebmpapst.com)
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Gough Lui over 3 years ago

That's a tricky one rscasny. The datasheet itself claims the board to be a 180-265V AC Input 0.35Arms/phase (70W) 6380RPM for Electronically Commutated (EC) Centrifugal Fan for High-Voltage Single-Phase Brushless DC (BLDC) Motor for Fan Application. I feel this is very much pointing to a very specific intended application and fan, but I think the device itself is actually quite general instead.

The fan noted inside the datasheet is an ebm-papst unit, model NRG118/0800-3612 EC Centrifugal Fan. It seems this fan is quite difficult to get, but probably the safest bet, but what is surprising to me is that the motor is probably speed controllable by putting in a signal into the PWM Input line itself, thereby seemingly not needing the "inverter" at all.
In fact, most of the EC motors I've come across are just like this - for example, the ebm-papst R3G190-RC05-03 which element14 does have (but is a little bit over-powered):
This makes me extremely confused why the product would claim to be for EC fans when EC fans seem to have the functionality for speed control built into them. It's also confusing to me because many BLDC motors have internal electronic commutation already as part of the controller board ... but also many of these are for low-voltage, as high-voltage BLDC motors are relatively uncommon (although they do exist).

Perhaps instead, the board may be used with ordinary AC synchronous motors to provide them the ability to be electronically commutated? Perhaps this is a point that needs clarifying ... unless I'm completely being silly and missing something entirely. Perhaps would a single-phase capacitor induction motor work, in which case the Orion Fans OA180APL-22-1 TB or WB units could work? Of note is that none of these fans are EC fans, nor are they necessarily intended to be controlled this way, but it seems more logical to do this type of control with a non-EC fan as an EC fan should have the smarts built into it?

This brings me to the second point about the board - in itself, it is essentially a single-phase "full bridge" which essentially allows an input logic signal to either turn on the high-side or low-side switches on each half.
In itself, this is not quite a full inverter. It's the power-stages of an inverter, but you need some "intelligence" to generate the correct driving patterns (possibly reading feedback from the motor) to make the motor turn. This can be achieved with a microcontroller in theory, but of course, some care is necessary to avoid "abusing" the motor even if by accident (even though the bridge's own intelligence may save itself).

- Gough
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rsjawale24 over 3 years ago

As per the datasheet of the board it can give 0.35A RMS and 70W output power and 6380 rpm.
ebmpapst manufactures motors and they have a good range of BLDC motors which fit well within the specifications of the board. But, unfortunately, they are all 3 phase motors.

Now I'm very curious to know if there are any single phase BLDC motors with high power specs.

Links to ebmpapst-

https://www.ebmpapst.com/de/en/products/motor-and-drive-systems.html

Product catalog for Internal rotor BLDC from ebmpapst
https://www.ebmpapst.com/content/dam/ebm-papst/media/catalogs/products/Catalog_ECI_EN.pdf
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