Brett_celicacoupe wrote:
my understanding was that the input voltage = a square wave with the same voltage. the pedal input then varied the duty cycle of the square wave... 2 frequencies are selectable in the software.
The Controller takes the battery voltage, and switches it across the motor, on and off.
In the case of the Soliton, you can select the switching frequency, lets call it 10kHz
That means every 0.00001 seconds, the switch turns on
Your throttle limits both current and voltage
So if your throttle is at 50%, it means 300A and 72V limit (actually 50% duty cycle limit)for a 144V pack)
so, for each of the 10'000 times the switch turns on, when the current goes past 300A, the controller turns the switch off.
At low speed, that can be as low as 1% duty cycle.
If your motor is spinning fairly quickly, and has substantial back emf, the 50% duty cycle limit (voltage limit) may be reached first, in which case it turns off before the current reaches the 300A limit.
It is setup this way to allow a relatively smooth transition between torque control and speed control.
Much more apparent when driving a conversion that has retained the gearbox.
With a direct drive conversion, the throttle mapping is usually reset so that the current limit curve is steeper. In the case of the Zilla, it means that at 50% throttle, current limit is 100%, duty cycle limit is 50%.
but at 25% throttle, current limit is 50%, and duty cycle limit is 25%.
The old way of doing it where the throttle only limits duty cycle (so 10% throttle = 600A or 10% voltage Max) has been done away with long ago.
Unless you use a curtis....
Matt
