I am trying to control BLDC, but always torque ON.
As I searched, common BLDC controllers restrict power of BLDC motor proportional to speed.(torque increases as speed up, almost 0 torque at initial state)
I want to control BLDC like servo motor, almost constant torque and just rotation of vector(sum of U, V, W).
First, I bought common BLDC controller. JYQD V7.3E2. Then I recognized situation I mentioned upper.
So I tried this thing follows. I removed jy01(main pwm generate chip), and I put PWM directly to IR2101.
but output voltage was not as I expected. That was half-side trapezoidal shape(000000555543 like level voltage), not both-side trapezoidal shape(000034555543).
1. So I ask for how to make these voltage output goes both-side trapezoidal.
Then, I attempted to make BLDC controller just itself.
I studied about ‘high and low side driver’ and ‘bootstrap voltage’ etc.
So I used arduino UNO and IRFZ44N(N-mosfet)s to control motor, but It wasn’t work. I think It is because of bootstrap voltage.
2. If I use two N-mosfet(one has low Vth and the other has high) apply them to voltage and current gradually increase, enough to make BLDC move.
All I want is just 1) holding torque at 0 speed, 2) simultaneous and direct speed control(do not wait stop until inertia doesn’t affect when break on).
My idea is set voltage of each pole of BLDC motor, U, V, W as sum of three vector has constant length(maybe power or torque to some direction) and control just direction of them by shift phase.
3. If someone knows how to control BLDC as I mentioned with low cost and simply, please share to me.