Vector Control of Asynchronous Motors

Vector control of asynchronous motors is an advanced speed regulation technique that achieves high-precision control of motor performance by decoupling the torque and magnetic field components. Its core principle involves mimicking DC motor control methods by decomposing stator current into excitation components (producing magnetic fields) and torque components (generating torque) for independent control. The system implementation primarily follows these steps: First, coordinate transformation converts the motor model from a three-phase stationary coordinate system to a two-phase rotating coordinate system, simplifying the control structure algorithmically. This can be implemented using Clarke and Park transformations in code. Next, field-oriented control ensures the rotor flux remains aligned with the d-axis, achieving torque-field decoupling through proper angle calculation. The control system typically employs a double closed-loop structure: an outer speed loop and an inner current loop, integrated with PI regulators for dynamic adjustment. In programming, this involves implementing PID controllers with anti-windup features for stable operation. Simulation analysis serves as a critical method for validating control algorithms. By constructing system simulation models (e.g., using MATLAB/Simulink), developers can observe dynamic responses under various operating conditions like startup, speed regulation, and sudden load changes. Typical simulation results include speed tracking curves, torque response waveforms, and current component trends, which visually demonstrate system stability and dynamic performance through plotted data. The application of vector control technology significantly expands the speed regulation range and improves response speed of asynchronous motors, making it widely applicable in high-performance drives such as electric vehicles and industrial servo systems. Code implementation often involves SVPWM (Space Vector Pulse Width Modulation) techniques for efficient inverter control.