The invention relates to a PWM variable frequency
speed control system based on the control of a DSP, and belongs to the technical field of intelligent electrical
engineering and electric apparatuses. A motor and an
inverter are seen as a whole. A space
voltage vector analytical method is adopted for conducting
flux linkage and torque calculation on a
stator coordinate
system, and the torque is directly controlled through a selection of different on-off states of the
inverter.
Direct torque control is adopted in a control method, and is another novel efficient variable frequency speed control technology after the
vector control technology. The
direct torque control technology is adopted in the
stator coordinate
system for calculating the
flux linkage and the torque of the motor. Firstly, a dibit controller is adopted, two control signals are directly utilized in the
PWM inverter to generate output
voltage, and rotation transformation and current control are eliminated, so that the structure of the controller is simplified. Secondly, the
stator flux linkage is selected as a controlled variable, so that the model calculating the flux linkage cannot be affected by rotor change, and robustness of the
system is improved. Moreover, due to the fact that
direct torque control is adopted, rapid torque response can be acquired in the speed-up, speed-down and load change dynamic processes, and variable frequency speed control can be simply and effectively conducted.