Energy-saving frequency converter of induction motor direct torque control speed regulating system and structured approach

Abstract

The invention relates to an energy-saving frequency converter of an induction motor direct torque control speed regulating system. The energy-saving frequency converter is characterized in that stator copper loss, iron core loss, total loss and motor total loss of an induction motor can be obtained according to an inductance motor approximately equivalent circuit model in a stator magnetic field orientation d-q coordinate system, and a stator flux linkage calculation module is structured and placed in a direct torque control system to form an inductance motor energy-saving variable-frequency controller which is combined with a power converter to jointly form an inductance motor energy-saving frequency converter. Control inverter switch signals output by a switch logic meter in the inductance motor energy-saving frequency converter are accessed to an input end of switch signals in a three-phase IGBT (insulated gate bipolar transistor) inverter in the power converter. The energy-saving frequency converter of the induction motor direct torque control speed regulating system has the advantage of capability of obviously reducing power loss of motor operation and improving integral comprehensive performance of a motor driving system, simple structure, reliability in operation, low realization cost and especial suitableness for application occasions in light-loaded running state frequently or with frequently changing load.

Description

technical field [0001] The invention relates to an energy-saving frequency converter and a construction method of an induction motor direct torque control speed regulation system, which is suitable for high-performance induction motor speed regulation or servo system control, and belongs to the technical field of electric drive control equipment. Background technique [0002] Induction motors have the advantages of simple structure, robustness, high reliability, and low price. They are widely used in industrial and agricultural production and national defense, and their power consumption accounts for more than half of industrial power consumption. At present, frequency conversion technology is mostly used for speed regulation of induction motors. In order to make full use of the motor's rating and obtain the maximum output torque, the air-gap flux of the motor is always set to the rated value below the rated speed. Induction motors operate more efficiently near their rated o...

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Problems solved by technology

[0003] The present invention proposes an energy-saving frequency converter and a construction method of an induction motor direct torque control speed regulation system. The generation mechanism of induction motor loss, establishes the approximate equivalent circuit model of induction motor in the stator field-oriented coordinate system, and derives the quantitative relationship between the motor operating loss and the motor speed, output torque and stator current under certain motor operating conditions. And the power balance condition when the power consumption of the motor is extremely small (great efficiency) is given; the Hall sensor is used to detect the stator phase current and the DC bus voltage, the photoelectric encoder is used to measure the speed, and the voltage model is used to estimate the stator flux linkage and electromagnetic torque , construct the optimal stator flux calculation module, put the optimal stator flux calculation module into the direct torque control speed regulation system, and realize the high-efficiency and fast-response control of the induction motor

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