A
Hi guys,
I am currently trying to understand FOC using the VISSIM examples. I have some basic questions and would love to have some answers from experienced guys:
1) In AC motors what I simply understand that if I change the frequency I'll change the speed (rpm) of the motor and if I increase the voltage of the AC input (freq const) it will increase the torque..right?
2) In sensored FOC in Inverse Park Transform if I change the Q value voltage is changing causing torque change and D = 0...my question is how the theta angle will change and start commutation? Because when the motor is standstill the increase of Q only causes the Inverse Park Transform output to change a DC value (as the motor is not rotating). So is it the inrush of current causing minute movement which is sensed by the encoder and starts a cumulative action?
3) If so which direction the motor will turn? If I ask in a different way how do I make sure the motor turns to the right direction?
4) In VISSIM example pmsm32sim I have tried and it works without the current feedback. So what is the significance of current feedback here? As I already have Q axis PID limiting values?
5) Park Transform should give DC output of D and Q from Phase Current sensing. But in VISSIM simulation and in reality the D & Q output from the Park Transform block is noisy (AC) as the inputs itself. So my question is just theoretical or really used in practical circuits. or in the context of the VISSIM pmsm32sim what is the significance of using the Park transform in noisy current sensing?
I am currently trying to understand FOC using the VISSIM examples. I have some basic questions and would love to have some answers from experienced guys:
1) In AC motors what I simply understand that if I change the frequency I'll change the speed (rpm) of the motor and if I increase the voltage of the AC input (freq const) it will increase the torque..right?
2) In sensored FOC in Inverse Park Transform if I change the Q value voltage is changing causing torque change and D = 0...my question is how the theta angle will change and start commutation? Because when the motor is standstill the increase of Q only causes the Inverse Park Transform output to change a DC value (as the motor is not rotating). So is it the inrush of current causing minute movement which is sensed by the encoder and starts a cumulative action?
3) If so which direction the motor will turn? If I ask in a different way how do I make sure the motor turns to the right direction?
4) In VISSIM example pmsm32sim I have tried and it works without the current feedback. So what is the significance of current feedback here? As I already have Q axis PID limiting values?
5) Park Transform should give DC output of D and Q from Phase Current sensing. But in VISSIM simulation and in reality the D & Q output from the Park Transform block is noisy (AC) as the inputs itself. So my question is just theoretical or really used in practical circuits. or in the context of the VISSIM pmsm32sim what is the significance of using the Park transform in noisy current sensing?
