Research and Application of Inverter Power Source in Elevator Power Feedback System
|Course||Communication and Information System|
|Keywords||Feedback Inverter Power SVPWM Carrier-Based PWM DSP|
The phenomenon of low utilization of the conventional electric power wildly exists in people’s daily life. It is necessary that the energy which is available for collection and feedback should be made full use of. The inverter plays an important role in a power conversion device of the power supply system. It is an inverter that converts DC to AC to achieve the regeneration of the electric energy feedback. In the elevator power feedback system the inverter is adopted to drive the pump voltage on the DC bus to invert and make energy feedback, so as to achieve energy saving and stable the working conditions. However, the feedback inverter needs to be carried out under certain conditions. And the inverter must have the ability to output voltage waveform of high quality. As the maturing of the inverter technology and the constant optimization of digital signal processors, the pulse width modulation (PWM) has been widely used in the inverter technology. Especially, space vector pulse width modulation (SVPWM) is becoming more popular in inverter technology, rectifier, the governor and other control systems because of its low harmonic distortion, high current efficiency, fast response, easy-to-digital realization and other significant advantages.This paper describes the design of overall elevator energy feedback system, including the inverter control and grid control. Mainly based on the principles of digital SVPWM and space vector control method, combined with the powerful computing capabilities of the latest high-performance fixed-point DSP chip TMS320F28234 of Texas Instruments (TI), a power inverter control system was designed. By analyzing the intrinsic link between the space vector pulse width modulation (SVPWM) and the carrier modulation (Carrier-Based PWM), the SVPWM controlling algorithm can be transplanted to the PWM Inverter, and a unified carrier-based PWM equivalent implementation of SVPWM is proposed. This method does not need a large number of complex mathematical operations, greatly reducing the computation time and making digital implementation easily. According to the basic structure and performance of the chip TMS320F28234, the hardware circuit design methodologies of inverter power system, the software, the control algorithms and processes are given. The system consisting of simple circuit structure takes full advantage of the rich peripheral components of the chip TMS320F28234, and has ability of anti-interference. Experimental results show that the inverter control system is designed reasonably. SVPWM technique which is adopted in the elevator with energy feedback system can raise the energy utilization of the DC voltage for inverter circuit feedback, and reducing the total harmonic distortion of the inverter power.