The Research And Implementation Of Energy Feedback Device Based On Tms320F2812

With the development of power electronic technology and computer control technology, general converter is used widely in practice. However, the rectifier of general inverter is irreversible, which determines its limitation in speed regulation system. When the motor is in the regenerative braking condition (such as elevator descending), regenerative braking energy is delivered to capacitance of inverter’s DC side, and pump voltage is produced. External braking resistance and braking unit is usually used to consume energy in practice, which not only waste energy, but also make the calorific value of system increase. Nowadays, energy problem is received more and more attention, energy feedback device, which can feedback energy to power grid and save energy effectively, is the product under this background. The control method, software and hardware implementation is deeply studied in this paper, following contents have been studied.The working principle of energy feedback device is deeply studied, the mathematical model in different coordinates of energy feedback device is analyzed, PWM current control with fixed switching frequency, which is one kind of the direct current control strategy, is adopted to design the double closed loop control system with inner current loop and outer voltage loop.. On the basis of the studies above, energy feedback system is simulated in Matlab simulation platform, the feasibility of control strategy of energy feedback control system is verified by simulation result.The influence caused by dead time to current waveform of AC side is analyzed and dead time effect is compensated, considering the principle of energy feedback device, it is a PWM rectifier which works in the state of inverter, so this method is firstly applied in three-phase PWM rectifier, current waveform is showed obviously improved by experimental results, the distortion of current waveform THD<5%. The application in energy feedback device is currently testing.The hardware system of energy feedback device is engineering designed in this paper. The hardware is divided into main loop and control loop. Main loop is divided into the capacitance design of DC side, the filtering inductance design of AC side, the choice of power components, etc. Control loop is divided into the design of DSP control loop, the design of voltage and current sampling circuit, the design of communication circuit, the design of analog and digital I/O circuit, the design of drive circuit, the design of over-current, over-voltage, under-voltage, over-temperature, phase failure and phase lack protection circuit, etc. Author’s participating experience of design a100kW inverter is used for reference, the anti-interference ability is fully considered. The debugging of system and experimental results shows that the design of hardware completely meets the system requirements.The basic principle of software phase locked loop, the improvement of its accuracy is analyzed on the basis of existing research results. The software of energy feedback device is designed, C language is used to programmed, the software is divided into the design of main program and the design of interruption program, the corresponding flow chat is provided.The related experiments of energy feedback device is combined with the variable frequency speed control system of induction motor, the pump energy, which generated when motor slows down or brakes, is fed back to power grid through energy feedback device showed by experimental results, at the same time, the power factor is proved to be approximately-1.