| The field oriented vector control technology sprout in the 1970s, and in the 1990s the technology become maturity, then to the 21st century the products that based on field oriented control technology develop rapidly. Widespread application of field oriented vector control technology has taken ac motor VF control into a new development model. Although such as direct torque control, neural network control and fuzzy control techniques are developed after the field-oriented control, but so far field oriented vector control is no doubt the mainstream of the market, and will occupy a position in the fields of ac motor's variable frequency speed regulation for a long-term.The experiment platform studied in this paper is based on field oriented control ac variable frequency speed-governing, mainly hope to adapt to the high level of the development direction of college experimental teaching reform. This topic was on the basis of detailed analysis of the original hardware platform of the laboratory, and then made some corresponding improvements for its several inherent disadvantages, and at last designed the field oriented closed-loop control algorithm on the optimization designed hardware platform. The inverter circuit of original system with MOSFET power switch tube has a big volume and the design of the circuit is complex, so it goes against the system's integration design. This paper replaced divided MOSFET but took PS21564 intelligent power module as main switching device of the inverter circuit, this way not only simplified the design of hardware circuit, but also improved the reliability of the system. In order to make PS21564 switch signals'voltage match to PWM output waveform, this text made some local improvements for the drive isolation circuit. Then the paper redesigned the fault protection circuits between DSP and IPM so as to protect IPM device better and faster, this design increased hardware level interrupt after failure occurs. Finally, this paper designed movement control CARDS that based on PCI bus and DSP2812 core to satisfy the real-time demand of the field oriented control variable frequency speed regulation system.On account of the dilemma that the control algorithm of experimental platform of universities were opaque and students couldn't make second development, this paper developed the complete set of software and designed the man-machine interactive control interface system based on Visual C++ environment. This interface system mainly have the following functions: freely selecting motor control algorithms, freely collocating modulation mode, manually switching the start and stop of motor, dynamically adjusting operating frequency of motor, changing the motor speed; six drawing windows are clearly visible. The interface is friendly and clear at a glance. This system fundamentally solved the shortcomings that original variable frequency speed regulation system can only macroscopically observe motor running but couldn't macroscopically grasp the dynamic running parameters of motor. This paper adopted C language to write the field oriented closed-loop control algorithm, and detailed illustrated the programming design idea of every link of the closed-loop.Finally, on the brand new hardware and software experimental platform, taking three-phase asynchronous motor as control object, this paper respectively carried on the no-load starting experiment, carry-load running experiment, load mutation experiment and dynamic speed-governing experiment, the results showed that the ac variable frequency speed regulation system designed in this paper had good dynamic and static performance and achieved the experimental expectations and completed the task of graduation design very well. |
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