Sinusoidal modulation control methods and circuits for permanent magnet synchronous motors

A sinusoidal modulation control method for a permanent magnet synchronous motor, the method comprising:

• a) detecting rotor position information of said permanent magnet synchronous motor to obtain a plurality of rotor position signals and a rotor rotating speed measured value, wherein said plurality of rotor position signals comprises three-phase Hall signals that correspond to three Hall effect sensors;
• b) comparing said rotating speed measured value against a reference rotating speed value to generate an error signal, and generating a first regulating voltage signal based on said error signal using a proportional-integral (PI) regulator;
• c) receiving said plurality of rotor position signals and said first regulating voltage signal, and generating a full-wave U-shaped modulation wave by using said plurality of rotor position signals as a plurality of time references;
• d) generating a second U-shaped modulation wave by multiplying said full-wave U— shaped modulation wave with said first regulating voltage signal;
• e) comparing said second U-shaped modulation wave against a triangular wave to generate a pulse-width modulation (PWM) control signal;
• f) controlling a switch of an inverter with said PWM control signal to regulate a current of said permanent magnet synchronous motor;
• and
• g) regulating a rotor position angle by an external enable signal by using said external enable signal to shift said full-wave U-shaped modulation wave left or right of one of said plurality of rotor position signals to change said rotor position angle between a stator magneto-motive force and a rotor magneto-motive force to maximize torque generated at every ampere stator current.