Research On Energy Feedback Type Asynchronous Motor Load Testing System

Motor load test is widely used in scientific research and production, operation and maintenance of the motor, through tests to detect the motor whether reach to the requirements, or through the necessary tests to find method to improve motor design, thus its research has a very wide range of practical value and application prospect.This article is mainly aimed at the traditional motor load test system being with low test accuracy, low efficiency, low degree of automation, complicated operation and other shortcomings, through the use of S7-300PLC as a controller, select the Sinamics S120frequency converter as a driving device to design a set of energy feedback asynchronous motor load test system. The test system of the upper position machine using a computer equipped with a Starter, Step7and WinCC industrial software to automatic control and monitoring for the entire testing process. The system of the lower position machine using the Siemens S7-300PLC as a controller to automatic control components and enforcement procedures of the motor load test system. Using Siemens Sinamics S120frequency converter as variable frequency driving device and asynchronous motor to constitute the AC induction electric dynamometer to complete the loading for tested motor, and achieve precise control of the motor.This paper use a kind of load test systems with double frequency converter and dual-motor, and present the frequency difference control method to realize system runs, the system adopts AC drive mode, it uses two frequency converters and two asynchronous motor constitute AC asynchronous electric dynamometer. Two motors’ supply frequency is different, the motor of high frequency work in the electric state, and the low frequency work in the power generation state, issued by the energy stored in the middle filter capacitor of the frequency converter to supply for electric state of the motor, throughing the energy feedback device, electrical energy back to the DC bus for recycling, Thereby reducing the line power, realizing energy recycling, being reached to the purpose of energy saving.