Research On AC Variable Frequency Speed Regulation Experimental Platform Based On Direct Torque Control

Since the late 20th century, AC Variable Speed gets rapid development, and has been widely used. Following vector control technique, the technique of Direct Torque Control(DTC) has been developed from1980's.By quick development, DTC has been a new high performance AC driving technique. Although the frequency converter based of DTC has emerged, the AC variable frequency speed regulation experimental platform cannot experiment with direct torque control algorithm. In this paper, the author studies the technology of DTC, and exploit a AC variable frequency speed regulation experimental platform based on DTC for university.The paper not only studies the hardware of the AC variable frequency speed regulation experimental platform, but also designs the main circuit, detection circuits and protection circuits according to the need of the platform. When the inverter adopts discrete components as its switching elements, it will be complex and not reliable. So this paper selects IPM as the switching elements. By designing the bootstrap circuit, a single power-driven program is achieved. The paper designs opto-isolation circuit between IPM and DSP, thus improves anti-interference performance of the system. Direct torque control system has high requirements for real-time, so the control processor uses TMS320F2812 DSP.Currently, university AC variable frequency speed regulation experimental platforms have many problems such as poor maneuverability, control algorithm cannot be developed once more. In order to resolve these problems, the paper exploits the main control programs using VC, and designs the host controller interface(HCI). Students can select control strategy and control the motor by this HCI. This HCI can display dynamically the value of registers of DSP, so the drawbacks of common frequency control experimental systems are solved. Besides students can write new programs or modify the original programs. The paper writes programs of direct torque control algorithm. And presents the realization of modules of the direct torque control algorithm.Finally, experiments was made on the AC variable frequency speed regulation experimental platform. Through the no-load tests, load tests, disturbance tests and other tests, we achieved the direct torque control software algorithm which has good dynamic and static characteristics, and the structure of the system hardware platform also has good performance.