CCT™ Drive System

THE MOTORINO CCT DRIVING SYSTEM

In 2008, after two years of design work, Greenwit Technologies Inc, completed development of their new electric driving system. Now standard on all MOTORINO™ scooters, the CCT™ (Continuous Current Transmission) made our 500W electric scooters competitive with the torque and hill-climbing of 50CC gasoline motor scooters.  

The nature of electric propulsion also makes the full torque of the motor available from 0 RPM, making for faster initial acceleration. One would expect this excess torque would demand a greater load on the battery, but as you will read, this is not the case; the higher power peaks only make use of energy saved from a more efficient rise time.  This is a necessity, as any increases to the nominal current would disqualify the motor as bicycle-legal. This system can outperform any regular brushless or geared motor even when their power consumption is 50% higher than the CCT drive, offering over 60% more starting torque than conventional 500W BLDC.

 

The most significant unique quality of the CCT™ is the way the controller operates the motor according road conditions.  The rise and fall of pulses in a regular BLDC motor is sinusoidal. (Pic.1) When incline, increased speed, or wind resistance put more load on the motor the power consumption immensely increases and the motor efficiency drops drastically - as low as 20% as it approaches stall speed.  This loss of efficiency is accompanied by increasing heat generation, this can burn out controller, motor, or demagnetize the earth magnets. These peak-current conditions also shorten the battery life.

The CCT™  controller employs PWM (Pulse Width Modulation) in unique way. It changes the Duty Cycle of the motor continuously based upon interpolated information of road conditions received from a processor. That allows the controller to estimate the necessary torque at each moment and control it directly. It is doing that by dynamically modulating the width, peak, and rise of the pulsing, thus providing the right amount of power at the right time.By modulating the impulses just before and after the polarity reversal the CCT reduces detrimental induction interference at the inflection point.(Pic2) Reduced inflection interference and sharper, well timed power peaks save up to 58% of total energy, which depending on riding conditions can be used to boost the torque, increase the speed or simply save it for greater range. More efficient pulsing also reduces the power losses through heat generation.

In addition to clever pulse width modulation in the controller, the motor makes better use of those pulses because of the winding’s configuration. Coupled with the CCT controller the magnetic flux density reaches higher levels compare to a standard BLDC motor. The neodymium magnets are much wider and thicker than those found on conventional motors.  This has many benefits: increased torque, more current is collected during regenerative braking, and the motor is less susceptible to demagnetization under extreme heat.

 

THE CCT GEARS

As previously stated, the excess current- saved by sharper peaks and lower induction interference- can be put to use in three different ways.  The rider can select how to use their power without releasing the throttle by means of a switch below the right hand grip.  These ‘electronic gears’ are: high torque(T), high speed(S), and economy mode or high range(R).

 

 

 

 

 

When a steep incline slows the bike, the rider can select the high torque gear.  This setting broadens the pulses; energizing the stator for longer periods to lessen RPM drop between steps.  A processor in the controller continuously monitors motor load and RPM to determine the maximum achievable speed, and modulates the pulses accordingly.  Note that this does not increase the current drawn by the motor; it remains continuous (hence continuous current transmission)- whereas a conventional motor will always try to reach its maximum speed by drawing more power. In high torque mode the CCT power train can deliver enough torque to move a total weight of 330Lb up a 24% incline!!

On flat ground and shallow inclines the rider will want to use the high speed gear.  In this setting the processor narrows the pulse curve, increasing its peak.  This higher peak increases the motive power allowing the bike to reach higher speeds - again without increasing the current consumption as we are simply using power saved by the delayed rise.  The high speed gear allows a bike and rider of a combined 450lbs to summit a hill up to 11% gradient without any perceptible loss of speed.  If the high speed gear is used on steeper hills the rider may feel more pull initially, but the speed will drop off more quickly than it would in high torque mode.

When a rider needs maximum range they should make use of the economy mode whenever possible.  The CCT system still works on the modulated regime, but does not apply the excess power in the vertical (higher peaks) or horizontal (broader pulses) direction.  It simply decreases the load on the battery.  The power peaks are just as high as they would be on a conventional BLDC, with the same motive power, but we end up with power savings up to 50% depending on motor load.  There will be a drop in speed and torque compared to the other two gears, however, the economy mode is best used on flat ground when your range is priority. Riding on economy mode can extend your range up to 20km!

 

REGENERATIVE BRAKING

Almost all BLDC employ a regenerative brake, but the larger magnets and unique winding of the CCT driving system make the process much more worthwhile.  The stopping power is so great that the mechanical brakes are nearly made redundant- only being needed as the motor RPM approaches zero.  This not only extends the scooters’ range by returning more energy to the battery, but prevents excessive wear on the disk brake pads, extending their life.

 

CONCLUSIONS

Greenwit Technologies’ CCT driving system is a completely unique system. All components (stator winding and laminated electromagnets, larger rotor permanent magnets, controller logic and commutation table, and robust connecting wires) are designed in Canada and are not found on any other brand of E-Scooter.  Vastly improved torque and efficiency are great, but perhaps the most impressive aspect of the driving system is its reliability.  It is completely solid state, the spinning rotor and its bearings are the only moving parts.  The motor and controller are well sealed and resistant to corrosion and can carry a rider for thousands of kilometres without servicing.

 

CCT™ driving systems are only available on our new XPd, XPs, XPn, XPr, XPh,  XPv,  and BTr models.

 

BEWARE OF IMITATORS

We have noticed that many manufacturers recently started offering “three gear“ switches, in an attempt to mimic the success of our driving system. From our testing we found that these ‘three gears’ simply provides three different levels of current to the motor. This increases the torque at the expense of the higher input power, consuming the battery much faster and increasing the pressure on the switching system and overheating the motor and controller