Vector Control of Permanent Magnet Synchronous Motors (PMSM)

Permanent Magnet Synchronous Motors (PMSM) have become crucial research subjects in modern motor control due to their high power density and efficiency characteristics. Vector control technology, as the core control strategy for PMSM, enables decoupled torque and flux control similar to DC motors, making it particularly suitable for high-precision applications involving medium-inertia motors.

During implementation, establishing an accurate mathematical model of the motor is essential first, including voltage equations, flux linkage equations, and motion equations in the dq-axis coordinate system. For medium-inertia motor characteristics, simulation parameters must focus on key parameters like rotor inertia, stator resistance, and dq-axis inductances, which directly influence the dynamic response and steady-state accuracy of the control system. In code implementation, these parameters are typically defined as structure variables or global constants, with dq-axis transformation functions handling the coordinate system conversion.

High-precision control typically adopts the id=0 control strategy, implemented through a three-loop structure comprising current loop, speed loop, and position loop. The current loop ensures fast torque response, the speed loop guarantees stepless speed tracking, and the position loop maintains final positioning accuracy. In programming, each loop is usually implemented using PID controllers, where the current loop requires the highest bandwidth and is often sampled at PWM switching frequency. Simulation must pay special attention to matching relationships between current sampling frequency, PWM switching frequency, and control system bandwidth.

The parameter simulation phase should include three main stages: motor parameter identification, controller parameter tuning, and dynamic performance verification. For medium-inertia systems, a variable carrier frequency SVPWM modulation strategy is recommended, increasing switching frequency in low-speed regions to ensure control precision while appropriately reducing frequency in high-speed regions to minimize switching losses. Code implementation typically involves lookup tables or real-time calculation algorithms for carrier frequency adjustment based on speed feedback.

In practical engineering applications, enhanced algorithms such as cogging torque compensation and parameter adaptation must be considered to address control challenges from sudden load changes and parameter variations. Through proper simulation parameter settings and control strategy optimization, vector control can enable PMSM to achieve ±0.1% speed control accuracy and position control precision within ±5 arcseconds in medium-inertia applications. Algorithm implementation often includes adaptive observers and compensation tables stored in microcontroller memory.