FOC motor control requires several PWMs. Introduction to FOC control algorithm

How many pwm are needed for foc motor control

FOC (Field-Oriented Control) motor control requires the use of two PWM signals to control the motor, which are divided into general PWM and extended PWM.

Generally, PWM is used to control the DC bus voltage of the motor. Its output frequency is generally several kilohertz, which can effectively suppress the noise and vibration of the motor. The DC voltage is adjusted by the duty cycle of PWM, thereby achieving speed and torque regulation of the motor. Generally, PWM is implemented by the built-in module of the development board or control chip.

Extended PWM is used to control the current of the motor. Its output frequency is generally set much lower than the frequency of general PWM to ensure the stability and control accuracy of the circuit. The task of extended PWM is to convert the current control command of the control algorithm into the phase current of the motor, thereby achieving torque and speed control of the motor. In FOC control, extended PWM generally needs to be implemented by the developer based on the motor parameters and control algorithm.

Therefore, FOC control needs to use two PWM signals, general PWM and extended PWM, to control the motor. General PWM is used to control the motor DC voltage, and extended PWM is used to control the motor current. The frequency and duty cycle of PWM control also need to be adjusted according to the specific motor control requirements and hardware conditions.

foc control algorithm

FOC (Field-Oriented Control) is an advanced motor control algorithm. Its basic idea is to convert the motor control problem into controlling the motor current vector, thereby achieving torque and speed control of the motor.

The FOC algorithm mainly includes the following parts:

1. Motor model: Model the motor and express the relationship between motor torque and current as a mathematical model, which can generally be described using the dq coordinate system.

2. Space vector modulation: Based on the motor model, the space vector modulation method is used to convert the voltage command into a specific PWM control signal, thereby achieving torque and speed control of the motor.

3. Torque control: The goal of FOC is to control the torque and speed of the motor, so the torque of the motor needs to be controlled. Based on the motor model, the components of the current vector in the dq coordinate system are controlled to achieve torque control.

4. Position control: In FOC, controlling the position and torque of the motor is equally important, and the motor position needs to be precisely controlled. PID control is usually used to achieve motor position control.

The advantages of the FOC algorithm are fast response speed, high open-loop stability, and low energy consumption, which makes it suitable for applications that require high-precision motor control. At the same time, the parameters of the FOC algorithm also need to be appropriately adjusted to meet the working requirements of different motors.