The basic principles of the permanent magnet BLDC motor

We talk about one type of permanent magnet bldc motor for electric bike. It’s a bldc electric bike motor , sometimes we also call it brushless dc hub motor .
The permanent magnet bldc motor and the bldc motor driver is a typical product for e-bike recently.
Generally the electric bike motor ’s stator windings is made of a three phase star connection, with the three-phase asynchronous AC bldc motor is very similar. The hub motor rotor has been magnetized permanent magnet, in order to detect the polarity of the hub motor, there are three halls sensors on the rotor.
The bldc motor driver is made by the power electronic devices and integrated circuits, its function is to receive electric bike motor ’s start, stop and brake signal so that control the hub motor to start, stop and brake; receive the position sensor signals and reversing signal, used to control the inverse power tube change the bridge off to produce a continuous torque; receive the speed command and speed feedback signal used to control and adjust the speed; provide protection and display
The main circuit is a typical voltage-type AC – DC – AC circuit, inverter and other pieces of alternating square wave frequency of 5-26KHZ modulation wave symmetry.
Permanent magnet NS alternating exchange, the position sensor phase difference of 120 ° U, V, W, square wave, combined with the six-state encoding signal forward / reverse signal generator: 101,100,110,010,011,001, through processing logic components to produce conduction of T1-T4, T1-T6 turns on, the T3-T6 conduction, T3-T2 turn-on, turn-T5-T2, T5,-T4 conduction, which means that the DC bus voltage is incremented A + B-, A + C-, B + C-, B + A-, C + A-, C + B-, so that the rotor turned a pair of NS pole, T1-T6 power tube fixed into six states followed by conduction. Each state, only two phase windings are energized in order to change a state, the axis of the magnetic field generated by the stator windings 60 ° electrical angle of rotation in space, the rotor follows the stator magnetic field rotation is equivalent to the space of 60 ° electrical angle position, the rotor in a new location so the position sensor U, V, W to produce a new set of coding according to the agreement, the new coding and changed the power tube combination of conduction, the magnetic field generated by the stator winding shaft forward 60 ° electrical angle, and so on, permanent magnet electric bike motor produces continuous torque, drag the load for a continuous rotation. Permanent magnet DC motor commutation is itself, rather than forced by the inverter commutation, also known as controlled synchronous hub motor.
Hub motor, bldc motor, electric bike motor supplier: Leaf Motor Technology Co.,Ltd
Website:https://www.leafmotor.com

LCD bldc motor controller for e-bike

There are two types of hub motor wheels are used for e-bikes. One type is hub bldc motor , the other is brushed hub motor. Because the brushed motor had some disadvantage of high noise, shorter-use life, low efficiency..
These days hub bldc motor wheels are used for electric bikes widely and had replaced brushed hub motor.
So more and more motor controller are showed in market. For example: cruise brushless controller , regen brushless controller, programmable brushless controller, lcd bldc motor controller…
Convert a bike to an e-bike, we should choose a hub bldc motor wheel with brushless controller and throttle, brake lever,on/off switches,disk brake,front&rear lights,horn..etc accessories
European like 250w hub bldc motor and North America prefer 750w / 1000w bldc motor. How to purchase a good brushless controller to drive this bldc motor .
Generally 250w bldc motor need to be driven by 6-MOSFET brushless controller, and a 9-MOSFET motor controller dirves a 750w bldc motor,a 12-MOSFET brushless controller dirves a 1000w bldc motor.
Now nearly all types of brushless controller for e-bikes have cruise, alert, reverse, limited speed..etc. function.
If you buy 1 set 48V DIY kit, you had better to choose 48V 12-MOSFET/15-MOSFET brushless controller. Please don’t order 9-MOSFET motor controller to drive your 1000W brushless controller, it’s the heart of e-bike. 1000W bldc motor will bring larger current and high temperature, 9-MOSFET can’t afford.
For the bulk .of motor controller, larger, better. Larger bulk has better cool system.
In past, there was a guy sold regen motor controller, but nearly all sold regen controllers were broken in 30 days. Because when you brake, this regen controller will bring twice current to stop your e-bike, thus larger current would break MOSFET directly.
Now programmable controller is still showed in market. This brushless controller seem has nice face, but its head is small, can’t stuff more MOSFET. Use this brushless controller to drive 750w / 1000w bike system and break this nice face controller is normal. Don’t be arrest by programmable. You will find nothing for actual use when you use.
We have LCD cruise controller, more MOSFET, don’t worry your motor controller will be broken.
LCD bldc motor brushless controller for e-bike.
Bldc motor, motor controller , brushless controller supplier: Leaf Motor Technology Co.,Ltd
Website:https://www.leafmotor.com

The issue about 250W hub motor electric bike kit

Bought 1 set of electric bike kit from one supplier in China two months ago. Sent more than 10 emails, haven’t gotten any reply. I met below issue, hope solve it.

When I was riding my electric bike three weeks ago, the 250w mini front hub motor suddenly started to make a strange and strong noise. If I try to turn the twist throttle on when the e-bike doesn’t have any load, I keep the hub motor wheel in the air. The electric bike motor works fine and electric bike kit does not make any noise.

However, if I try riding my electric bike and turning the throttle on, the electric bike motor starts making a strong and continuous noise. I tried to riding my bike keeping the brakes continuously pressed and any noise appears so it seems to be some electric problem. It is very strange and I am so much worried.

I took off electric bike kit wheel and used screwdriver to disconnect six screw nuts, took apart hub motor cover and found there was a rotor-winding, two bearings, three sets of 42-gear, 1 set of 21-gear on the axis, 1 set of 81-gear on the hub. There wasn’t any impurity inside the hub motor. Re-install and test electric bike motor wheel, still have the same problem. Don’t know what’s the problem.

Contact my supplier many times and can’t get any reply. I looked for answers by google, yahoo and bike forums, still can’t find the correct answer. Yesterday I got a message from my US friend about there was a company, leaf motor can help me. So I sent an email to leaf motor.

Surprisingly just half an hour past, leafmotor replied me and asked me to check the bearings. How to check hub motor bearing? Take off two bearings from axis, and use little finger to hold inside of bearing, the other hand to turn bearing, faster, better. If you can hear some noise from bearing that can confirm the problem comes from electric bike motor ‘s bearing. At last, I found there was a bearing was broken. According as the bearing model, I bought two new ones in market and replaced them.

Test electric bike kit wheel in the air, no noise. Brake hub motor wheel, still no noise. Nice, Have sloved it.

I should thank leaf motor that help me and I found fun throught repairing electric bike motor. Now I decide to buy leaf ‘s electric bike kit if I have need and will recommend my friends to order leafmotor’s electric bike motor, bike kit…

Though I haven’t ordered any goods from leafmotor by now. But they are very professional, has best service and believe they have high quality products.

Hub motor, electric bike motor, electric bike kit supplier: Leaf Motor Technology Co.,Ltd

Website:https://www.leafmotor.com

power on the electric bike hub motor was gone

Electric bike hub motor kit was gone, how to solve it?

Received my electric bike kit .Product list:

1.26” 36V 250W front brushless geared hub motor wheel

2.36V 6-MOSFET brushless motor controller working with LCD(display speed,mileage,battery gauge..)

3.standard black twist throttle with battery gauge

4.brake lever with low voltage to brake

5.three button-ON/OFF switches that are used for control front&rear lights,cruise,horn…

Check rim whether in the middle of fork and the direction of hub motor runs.Then I have installed everything on my bicycle according as instruction manual and the electric bike kit worked fine.

I was running e-bike about 25km and then I stopped the electric bike motor . Charged the electric bike battery because I was staying there for some hours. Started on the way home and after some heavy hills (about 3 km)it was completely dead. The electric bike kit system was running like normal up to this, but suddenly all power on the electric bike motor wheel was gone.

Those three led lights on twist throttle for electric bike battery were still lit. I tried to turn e-bike off and on again, but same result.

Today the electric bike kit is still dead.

Do you have any idea? Measured 0,1 Ohm between the electric bike motor(hub motor phase wire: yellow, green, blue).Infinity between hub motor cable and hub motor cover. So it does not look like it is burned. The electric bike motor controller has 41,8 Volt input.

Measure the hub motor hall sensor:

Red, black, yellow, blue, green wires.

1.The voltage between red and black is 4.5V;

2.The voltage between yellow and black is 4.2V or 0V,(When use hand to turn hub motor, the voltage will change from 0~4.5V~0~4.5V)

3.The voltage between blue and black is 0.2V; (When use hand to turn hub motor, the voltage could not change)

4.The voltage between green and black is 0.1V. (When use hand to turn hub motor, the voltage could not change)

From above test data, I doubt there were two hall sensor inside the electric bike motor that were broken.

Electric bike hub motor kit was gone, how to solve it?

Hub motor, electric bike motor, electric bike kit supplier: Leaf Motor Technology Co., Ltd

Website:https://www.leafmotor.com