Study And Design Of A Variable-Frequency, Variable-Voltage Power Supply Based On DSP

In recent years, with the acceleration of the world economy integration and the rapid development of some special industries, the application of variable-frequency power source becomes wider. People have higher request on the quality, functionality, performance, intellectualization and cost of variable-frequency power source. However, the power products based on analogue circuit technology cannot be improved, neither of assured quality, so they cannot meet some customers' requirements. That has seriously affected the development and technological progress of the related industries. Therefore, the study of high-performance intelligent variable-frequency power source will be of great importance, and it also has a positive role in promoting the whole inverter industry in technology fusion.The thesis presents a method based on DSP (digital signal processor) technique, by which a three-phase, variable-frequency variable-voltage power supply can be achieved. After detailed study of the DSP hardware architecture and software programming of SVPWM (space vector pulse width modulation) control algorithm and technical principle, using high computing power of DSP, together with a lot of peripherals used in control field, all of these can be achieved: production of digital SVPWM waveform, output of variable frequency, tracking control of phase and voltage, and the algorithmic control of PI. SVPWM wave, after amplified, is used for the gate driver of insulated gate bipolar transistor in IPM (Intelligent Power Module), and then it can control output of power's voltage and frequency, and then achieve intelligent digital control of variable frequency power. That will greatly enhanced the integration degree of the circuit, reduce the cost and the difficulty of the process, and improve the reliability of the product.This paper focuses on the inverter output of variable-frequency, variable-voltage power supply, and digital control of that. The work lies mainly in building of the hardware platform and the software foundation of 10kVA, 400Hz power. First, the author designed the main circuit of the power source, especially used the IPM module that has the conveniently-controlled driver and the perfect protective function for the inverter circuit; thus accomplished the manufacture of interface circuit and the power supply circuit of IPM; then designed the hardware circuit based on DSP of control system, SVPWM interface circuits, relevant analog signal conditioning circuit, A/D conversion and SCI communication and CAN interface circuit; and finally completed the overall software planning and process design and programmed the SVPWM control algorithm and the PI control algorithm in C language. The prototype test was performed on the hardware platform, and satisfying results yielded. Comparing with the analog power supply based on SPWM, our product has a higher usage of DC power as well as a better quality of the output waveform.Based on the experimental prototype, the author studied the schedule of paralleling variable-frequency power sources by CAN Bus. The paper analyzed the conditions of multiple-power-sources paralleling and then realized the online expansion and redundant design of power products based on CAN bus.The whole design, of simple structure, clear module and full functions, can be easily upgraded and extended. The design fully reflects with high-frequency, digital, modular developing trend of current variable-frequency power. This power product has advantages such as small size, high efficiency, low noise, wide frequency range, high precision and reliability, good sinusoidal signal output. So, it should be of good practical value.This subject referenced a great deal of data, as well as the latest technology of inverter's development. It is a useful attempt for all-digital variable frequency power research and development. All was analyzed in detail, from the realization of each functional local circuit to the working principle of entire source circuit. The results of power prototype test show that the performance and function can meet the expectant objectives and requirements.