Working principle of ESC

Posted by Fengyukun on

An electronic governor is an electronic device used to control the speed and torque of a brushless motor. The main principle is based on PWM (Pulse Width Modulation) technology and closed-loop control algorithms.

In an electronic governor, PWM technology is used to control the current and speed of the motor. It controls a constant-value DC power supply through a switching tube (usually a MOSFET) to produce a square wave of a certain frequency, and controls the motor current and speed by adjusting the duty cycle of the square wave. A three-phase full-bridge circuit is usually used in electronic speed controllers to drive brushless motors, in which each bridge arm is composed of multiple MOSFETs, and through different MOSFET switching combinations, the motor can be forward, reverse and speed control.

In addition, to achieve precise control, the electronic governor uses a closed-loop control algorithm, usually using a PID (proportional, integral, differential) control algorithm. This algorithm achieves precise control of motor speed by comparing the actual speed of the motor with the desired speed and making corresponding adjustments.

In electronic governors, motor position detection and motor parameter identification are also required to achieve accurate closed-loop control and protection functions. At the same time, the electronic governor also needs to carry out fault protection such as over-current, over-voltage and over-temperature to ensure the safe operation of the motor.

In addition to PWM technology and closed-loop control algorithms, the electronic governor also involves the following aspects of operation:

Motor position detection: Electronic governors need to detect the rotor position of the motor for closed-loop control. Position detection is usually performed using sensors such as Hall elements or encoders, or electronic phase change technology is used to achieve position detection.

Motor parameter identification: In order to achieve accurate control, the electronic governor needs to identify motor parameters, such as resistance, inductance, electric potential and other parameters. Usually use least squares and other algorithms for parameter identification.

Fault protection: During the operation of the motor, fault conditions such as overcurrent, overvoltage and overtemperature may occur, and corresponding protection measures need to be taken, such as overcurrent protection, overvoltage protection, overtemperature protection, etc.

Electronic phase change: The electronic governor uses brushless motor for control, which requires electronic phase change technology to realize the motor's commutation. Electronic phase change controls the on and off of different MOSFETs by detecting the rotor position of the motor, thus realizing the forward and reverse rotation and speed regulation of the motor.

In addition, electronic governors require attention to the following points:

PWM frequency: The selection of PWM frequency in the electronic governor needs to be adjusted according to the specific brushless motor parameters, generally between 1kHz and 20kHz, to ensure stable motor operation.

Control algorithm: The PID control algorithm in the electronic governor needs to be adjusted and optimized according to the characteristics of the motor in order to achieve a more accurate control effect.

Motor protection: In order to protect the safe operation of the motor, the electronic governor needs over-current, over-voltage, over-temperature and other fault protection, while the need to pay attention to the motor load and operating environment.

Power supply selection: electronic governor requires a stable and reliable power supply, generally using DC power supply, the choice of voltage and current needs to be adjusted according to the rated parameters of the motor.

Signal processing: The signal processing in the electronic governor requires filtering and amplification and other operations to ensure the accuracy and stability of the signal.

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