PWM variable frequency speed control system based on control of DSP

Abstract

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.

Description

technical field [0001] The invention relates to a PWM frequency conversion speed regulation system based on DSP control, which is suitable for AC frequency conversion speed regulation of motors and belongs to the technical field of intelligent electrical appliances. Background technique [0002] After searching, there are mainly the following types of AC speed control technology at present: 1) Voltage-frequency coordinated control means that the ratio of voltage amplitude to frequency is kept constant below the fundamental frequency during speed control to achieve constant torque speed control Running, when the speed is adjusted above the base frequency, the output voltage is maintained at the rated value, so that the magnetic flux is reduced inversely proportional to the frequency, and the weak magnetic constant power speed regulation operation is realized; Control, the given speed and the detected speed deviation are obtained by the PI regulator; 3) vector control, which i...

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Problems solved by technology

[0003] In the prior art, the voltage-frequency coordinated control has a simple structure of the speed regulation system, which can only meet the occasions where the general speed regulation requirements are not high; the speed closed-loop slip speed regulation is based on the steady state mathematical model of the asynchronous motor, and the dynamic time The magnetic flux is not constant, so it will affect the actual dynamic performance of the system; vector control, its structure is complex, and the calculation of vector transformation is large

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