The invention relates to a
voltage orientation frequency-vary controller of an opening-ring no-speed sensor, and a controlling technology of a sensing motor, which overcomes the problems of the poor loaded capacity and the light loaded oscillation of a motor caused by the influences of the factors of the
voltage decrease of a
stator resistor, rotating difference frequencies, dead areas, and the like in the low-speed running of the traditional constant-
voltage frequency-ratio control. The voltage orientation frequency-vary controller is composed of the following units, i.e. a
current sensor, a vector coordinate changing unit, a PI adjustor, a calculating unit of
voltage boosting amount, a sliding-frequency calculating unit, a frequency
adder, a first operation unit, a second operation unit, a third operation unit, a fourth operation unit, a fifth operation unit, a sixth operation unit and a SVPWM unit. The PI adjustor is used for controlling the no-power current, and the problem of the light-loaded oscillation of the sensing motor is effectively inhibited. The product of the power current and the motor
stator resistance is used as the
voltage boosting in loading, the loaded capacity of the motor is obviously improved, and the low-speed performance of the motor is greatly improved.