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Presentation of the FOC controller
How to convert RPM to the Frequency of the sinusoid of current that must be generated for each phase, considering the number of pole pairs.
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Introduction
The PMSM FOC library can be used to quickly evaluate ST microcontrollers and complete ST application platforms, as well as to save time when developing Motor Control algorithms to be run on ST microcontrollers.
This PMSM FOC library is written in C language, and implements the core Motor Control algorithms (reference frame transformations, currents regulation, speed regulation, space-vector modulation, energy efficiency optimizations) as well as sensors reading/decoding algorithms (three shunts, ST-patented single DC link shunt, isolated current sensors, incremental encoder, hall sensors) and a sensorless algorithm for rotor position reconstruction.
When deployed with STM32F103xx High-Density / XL-Density devices (Flash memory density between 256 and 512 Kbytes / 768 Kbytes and 1 Mbyte), the PMSM FOC library enables simultaneous dual FOC of two different motors.
The library can be customized to suit user application parameters (motor, sensors, power stage, control stage, pin-out assignment) and provides a ready-to-use Application Programming Interface (API).
A user project has been implemented to demonstrate how to interact with the Motor Control API.
The project provides an LCD User Interface and a USART User Interface, represents a convenient real-time fine-tuning and remote control tool for the motor control application.
A PC Graphical User Interface (GUI), the ST Motor Control Workbench, allows complete and easy customization of the PMSM FOC library. In conjunction with the STM3210B-MCKIT motor control starter kit, a PMSM motor can be made to run in a very short time using default parameters.
Presentation of the FOC controller
Click here to get presentation concerning STEVAL-IHM036V1
Click here (pdf 1,3Mbyte) to get the complete FOC controller presentation.
-
How to convert RPM to the Frequency of the sinusoid of current that must be generated for each phase, considering the number of pole pairs.
LINK
SW:
MANUAL:
STM32 Page
INDEX
Introduction
Presentation of the FOC controller
How to convert RPM to the Frequency of the sinusoid of current that must be generated for each phase, considering the number of pole pairs.
LINK
Introduction
The PMSM FOC library can be used to quickly evaluate ST microcontrollers and complete ST application platforms, as well as to save time when developing Motor Control algorithms to be run on ST microcontrollers.
This PMSM FOC library is written in C language, and implements the core Motor Control algorithms (reference frame transformations, currents regulation, speed regulation, space-vector modulation, energy efficiency optimizations) as well as sensors reading/decoding algorithms (three shunts, ST-patented single DC link shunt, isolated current sensors, incremental encoder, hall sensors) and a sensorless algorithm for rotor position reconstruction.
When deployed with STM32F103xx High-Density / XL-Density devices (Flash memory density between 256 and 512 Kbytes / 768 Kbytes and 1 Mbyte), the PMSM FOC library enables simultaneous dual FOC of two different motors.
The library can be customized to suit user application parameters (motor, sensors, power stage, control stage, pin-out assignment) and provides a ready-to-use Application Programming Interface (API).
A user project has been implemented to demonstrate how to interact with the Motor Control API.
The project provides an LCD User Interface and a USART User Interface, represents a convenient real-time fine-tuning and remote control tool for the motor control application.
A PC Graphical User Interface (GUI), the ST Motor Control Workbench, allows complete and easy customization of the PMSM FOC library. In conjunction with the STM3210B-MCKIT motor control starter kit, a PMSM motor can be made to run in a very short time using default parameters.
Presentation of the FOC controller
Click here to get presentation concerning STEVAL-IHM036V1Click here (pdf 1,3Mbyte) to get the complete FOC controller presentation.
-
How to convert RPM to the Frequency of the sinusoid of current that must be generated for each phase, considering the number of pole pairs.
Suppose to have a 3 phase motor. 
Suppose to have 20000 rpm, this means 20000 laps (mechanical) per minute.
And suppose that the motor is a 4 pole pairs.
The formula for calculate the mechanical frequency (MF) is:
MF = rpm/60
20000 rpm ==> laps (mechanical) per minute ==> 20000/60 = 333.33 per second (mechanical frequency)
To calculate the electrical frequency (Hz) is necessary multiplied the mechanical frequency by the number of pole pairs.
Hz = MF x Number_of_Pole
333.33 x 4 = 1333.33 Hz
This is the frequency of the sinusoid of current that must be generated for each phase.
But...
The sinusoid must be (Nyquist) at least twice but as we know it is not enough... we say that takes at least 10-12 times, (most bigger is, the better is) to get an accurate reconstruction of the curve... the PWM frequency is our sampling frequency (in the case in which the vector control is done every period of PWM).
So the PWM frequency is:
Fpwm >= 1333.33 * 12 = 16 KHz
Consider that 16 KHz is the minimum conditions.
If it is possible the suggestion is: go up in frequency but take care the switching losses.
Suppose to have 20000 rpm, this means 20000 laps (mechanical) per minute.
And suppose that the motor is a 4 pole pairs.
The formula for calculate the mechanical frequency (MF) is:
MF = rpm/60
20000 rpm ==> laps (mechanical) per minute ==> 20000/60 = 333.33 per second (mechanical frequency)
To calculate the electrical frequency (Hz) is necessary multiplied the mechanical frequency by the number of pole pairs.
Hz = MF x Number_of_Pole
333.33 x 4 = 1333.33 Hz
This is the frequency of the sinusoid of current that must be generated for each phase.
But...
The sinusoid must be (Nyquist) at least twice but as we know it is not enough... we say that takes at least 10-12 times, (most bigger is, the better is) to get an accurate reconstruction of the curve... the PWM frequency is our sampling frequency (in the case in which the vector control is done every period of PWM).
So the PWM frequency is:
Fpwm >= 1333.33 * 12 = 16 KHz
Consider that 16 KHz is the minimum conditions.
If it is possible the suggestion is: go up in frequency but take care the switching losses.
LINK
SW:
MANUAL:
