Tested Brainpower KSDLM25 1000W Sine Wave Controller

I bought this for $19 thinking I'd be lucky if it even worked at all.
The controller is advertised as follows:
*)38A max.
*)36v or 48v operation.
*)Sine Wave output.
*)Supports both Sensor or Sensorless operation
*)Autodetection/configuration of motor direction AND hall sensor wires (just get +/ground right).

Usage.
Wire up three motor windings and battery (but dont connect yet) to controller.
Wire up "orange" wire to red power (orange wire would connect to "ignition" on/off switch).
.....optional: hook up motor hall sensor wires.
Connect the two green "motor autoconfiguration" wires together.
Connect the throttle.
Connect battery. Motor will start to turn....if turning wrong way, roll throttle and motor will change direction. Once turning right way, pull apart the two green wires. Controller will remember setting.
View attachment 1


Findings:
Controller autodetects SENSORLESS motor....and remembers setting.
Controller also autodects SENSORED motor....and remembers setting.
Output is indeed Sine Wave! *****EDIT....is trapezoidal wave form....my bad]
36V cutoff OK....did not test w/48v pack....may try power supply in a few days dialed in at 48v?
Throttle is like a govenor whose RPM changes with throttle movement....RPM stays locked in when force is applied, amp-draw increases to maintain RPM.

Nice basic controller. Hope it holds up.

Looks like it's sort of a sine wave type, what might be called a six-step type. Rather than something that calculates the sine based on the actual motor characteristics and/or feedback from the motor phases, it is likely using a lookup table, so it's not as effective/efficient (or quiet, probably) as one that uses the motor characteristics...but it is simpler to use, and probably mroe than good enough for the price.

WOuld be nicer if it had a torque (current) throttle mode instead of speed throttle, but hey, for under 20 bucks....

Sine wave lookup table? Never heard of it.
I've heard of "modified sine wave" which is what you have described.
FOC and "Sine Wave" controllers utilize the same MOSFET switching technology as PWM (square wave) controllers.
They simulate sine wave by varying the number of pulses (more pulses higher wave form) and duration of each pulse (wider for all pulses more force applied to stator/armature).
The magnetic inductor characteristics of the motor windings smooth this power delivery mechanism out so power delivery is indeed a nice smooth sine wave.

The only way to get true sine-wave into the motor is to utilize heavy transformers or to utilize bipolar silicon (not switching, but analog) technology which is MUCH LESS efficient.

pullin-gs said:

Sine wave lookup table? Never heard of it.
I've heard of "modified sine wave" which is what you have described.

Click to expand...

Modified sine wave is a marketing term used by inverter manufacturers that means square wave with an "off" period in between. Trapezoidal drive is more common, and that's what it looks like on the scope.

Sine wave lookup tables are used by pretty much anything that has to generate a sine wave.

The only way to get true sine-wave into the motor is to utilize heavy transformers or to utilize bipolar silicon (not switching, but analog) technology which is MUCH LESS efficient.

Click to expand...

You can get true sine wave current into any motor (or load) without a transformer; usually an LC network is used as a filter. Many transformerless inverters do this with motors, grid tie systems and off grid power.

pullin-gs said:

Sine wave lookup table? Never heard of it.

Click to expand...

It's common in the cheap sine controllers. (even the trap controllers probably use it).

There've been some discussions about it, though I don't recall what kind of detail they go into. Here's one:
https://endless-sphere.com/forums/viewtopic.php?t=60983
and another
https://endless-sphere.com/forums/viewtopic.php?t=59232

more on the web in general, and here on ES over the years.

The only way to get true sine-wave into the motor is to utilize heavy transformers or to utilize bipolar silicon (not switching, but analog) technology which is MUCH LESS efficient.

Click to expand...

(Computational, vs lookup) sine, FOC, etc. make a waveform that is not a "six-step" waveform like the one this (and other cheap sine controllers) make. It's as close to a sine as you get with a PWM waveform (necessary when using switching technology, as you noted above).

Takes a faster and more expensive MCU with more memory to calculate the sine based on motor parameters, than it does to just use a simple small lookup table with segments of a sine-like waveform...so the cheap controllers use lookups.

billvon said:

Trapezoidal drive is more common, and that's what it looks like on the scope.

Click to expand...

Yes, you are right. I updated my initial post. Thanks for the clarification/education.
I took first trip (two miles) on my new/second build (first e-build was a LIPO-powered kayak).
Setup is:
TerraTrike TourII...a 20" 38lb (w/o epower stuff) tadpole recumbent.
Q128 500w motor: $150..... $45 for 20" wheel rim and spokes.
This controller, w/15A fuse protection: $19
Home-built 8AH 10S LIPO pack: $50
The first thing I noticed was the smooth power delivery (sensor mode) and very very little noise....tiny bit of gear meshing wine which was much louder than motor commutation noise! I was not expecting it to be so quiet...very happy!
In sensorless mode motor will hesitate at times when pulling out. Blew my 10A test fuse on the bench one time when it was spazzing out.

If this motor, 8AH 10S-pack, controller setup proves worthy of my expectations (15MPH, an hour+ ride times, QUIET(!)), I will role with the motor/controller/10S-pack configuration and REPLACE LIPO pack with a quality 36V 11AH LI-ION (Panasonic cells) off-the-shelf pack....LIPOs scare me (been doing electric RC for 22 years now)

I used this controller in FrankenScooter, a modified scooter frame using a Chinese 1kw motor in it's fork to make a wheelchair attachment.
I am elated by this deal; should go 36mph but I stopped at 26. Has reverse, 3 speeds, and cruise function AND I found out (it's not in the literature on it), that it has regenerative braking, ~10A @15mph!



FrankenScooter on the left. The first one was using the forks/framehead/motor off a KDX scooter but with a reversing controller. It's 36v/300W and around 20mpoh.
FS is 36/48V 1000w and I usually run it on 48v. It makes Little John look absolutely pedestrian! BUT, LJ weighs just over 26lbs and works great on city streets. On steep hills, it grinds down to ~3moph where 'FS zips up at 18.

I came to these forums 2 years ago when I started on this project and appreciate everyone's help