The Study On Single-Phase High Power Factor Reversible Rectifier

In recent years, people have being paid extensive attention to harmonic pollution produced by power electronic devices, among which rectifiers act as a great harmonic source. The percentage of rectifiers is very large in harmonic pollution because most of DC power is converted from AC power. Conventional working ways of rectifiers have some disadvantages, whether diode-rectifiers or thyristor-rectifiers. The obvious one is their harmonic pollution to electric networks. On the rectifiers, how to manage harmonic has been being the subject that many people study. One method adopted is passive, namely power factor correction (PFC) and another is active, that is, to find out some techniques from a rectifier itself to eliminate the harmonic and improve the power factor. Not only do thyristor-rectifiers produce harmonic current to electric networks, but also their factor is lower when deeply controlled. Although diode-rectifiers can improve the power factor , they can still input harmonic to electric networks.Besides, the voltage on DC bar can't be controlled for diode-rectifiers.The appearance of PWM rectifier offers a new way to solve the problem from the traditional rectifiers.In this paper, in order to solve the problem from the traditional rectifiers, a set of high power factor reversible rectifier scheme is designed. A method is introduced that reversible rectification can be realized with single-phase half-bridge circuit in this paper. In the plan of design, the fourth generation of IPM is used as the main half-bridge circuit and TMS320LF240X DSP with good performance and strong function is used as a controller. They make up the voltage sourse single-phase reversible PWM rectification system together.Operation principle and control strategy of the single-phase reversible rectification bridge is analyzed in the paper. A more deeply analysis and study on the reversible rectification half-bridge is made. The control way of hysteresis-current with good track performance for current is adopted and on the basis of Matlab/Simulink environment the simulation model of the rectifier is built up. The simulation result indicates single-phase reversible rectifiers have some advantages, such as high power factor, controllable DC voltage on bus bar and bi-directional flow for power. This lays a good theoretical foundation for realization of prototypein future. Besides, analyses is made on the realization of the control circuit based on the presented control strategy and with the assembly language of DSP, the control program is written according to the plan of design finally.