METHOD FOR REGULATING AC MOTOR SPEED OF ROTATION (ALTERNATIVES) Russian patent published in 2001 - IPC

FIELD: special- and general-purpose synchronous, hysteresis, and induction motors. SUBSTANCE: first alternative implies variation of motor supply voltage shaped by means of inverter by applying feedback signal proportional to phase of second derivative of motor phase current within one of ON/OFF intervals of inverter (π/3÷2π/3)+πn or (2π/3÷π)+nπ relative to π/2 value, where n = 0, 1, 2 ... According to second alternative feedback signal is shaped in proportion to phase at zero value of inverter input current second derivative zero within ON/OFF intervals of inverter relative to π/2 value of respective motor phase. Proposed method is also useful for damping oscillations of motor frequency of rotation. EFFECT: improved speed of response to variations in motor frequency of rotation. 7 cl, 7 dwg, 2 ex