Key Technique And Application Of Microcomputer Testing System With Dynamic Loading Simulation

In practical engineering application, the key difficult problems in current stages are how to obtain the accurate operation performance parameters and efficiency evaluation for the AC motors with dynamic load. Taking typical beam pumping motor (BPM) for example, this dissertation developed an indoor high precision microcomputer automatic test system for BPM, by theoretical analysis, numerical computation, experimental study and standard beam pumping unit (BPU) field test. The accurate energy efficiency test under complicated load conditions can be realized flexibly by adjusting the model parameters of host computer, the main works are as follows.1. The influences of non-standard equipments on the overall system accuracy is studied, such as instrument transformer, data acquisition card, host computer, and so on. is studied. The error analysis model of overall microcomputer automatic test system is established. Then, the calibration procedures of components and related software solutions are proposed to improve system measurement precision. Furthermore, the problem of precision selection of components according to the system design claims is solved effectively.2. In the application field that servo motor driven by inverter is used as load. It is comfirmed that there is additional torque resulting from windage or friction in the load torque through the real field test. This dissertation reveals the application status that the load precision is poor although the drive accuracy of inverter is high. Moreover, two high-precision control strategies which do not depend on parameters of inverter or motor are presented. Field test indicates that the steady state accuracy of PI and fuzzy control are approximately the same, but the latter has more fast dynamic response.3. Considering the shortage of existing model on solving accuracy and computing speed, a BPU practical simulation model available for on-line test is established, which adopt Dirichlet method to solve damping nonlinear wave equation of sucker rod. Taking load curve of BPM as a simulation object, this dissertation put forward a new concept of BPU "equivalent" model parameters which is solved with the method based on GA algorithm. Then, a set of test system with dynamic load test function is developed.4. Based on the comparison of the respective energy-saving principle of each energy saving measure for BPM nowadays and combining the geometry motion features of BPU four-bar linkage, the inherent relation between dynamic component of polished rod load and motor speed is analysed. According to the energy saving mechanism of BPU load curve adjustment, a sectionalized control technique based on frequency and voltage regulator is explored, which is suitable for periodic potential load. The achievement provides important theoretical support for further developing the energy-saving work of BPM.