Study And Implemention Of The Control Scheme Of Single-Phase Voltage Four-Quadrant Rectifier

As an important part of AC drive test system, the four-quadrant rectifier don't only keep the stability of middle DC voltage, but also achieve the power factor correction of the primary side of power transformation. The traction motor work as the inverter operating in regenerating mode, the phase of input current is shifted with n relative to the supply voltage, then achieving the unity power factor of energy feedback. The option of the four-quadrant rectifier control strategy has a significant impact on improving the grid power factor, reducing the harmonic of supply current, keeping the DC voltage stable and ensuring the normal operation of the inverter of motor side.This thesis presents the principle of sing-phase voltage mode four-quadrant rectifier, defines the switch function and establishes its mathematical mode. Then the current inner-loop controller, voltage out-loop controller and compound control system with voltage forward-feedback controller of type I and type II system are designed. At last, this thesis expounds the transient current controller and the predictive current controller that are based on the designation of compound control system. The results are simulated by Matlab show that the good dynamic, static characteristics and unity power factor of the four-quadrant converter can be achieved by using the transient current control scheme or the predictive current control scheme.The harmonic generation mechanism and the elimination theory of supply current have been analyzed for the case of the DC-side has no secondary filter circuit. The predictive current control and the transient current control have been improved by compensating the output voltage ripple. The peak-signal of the output voltage ripple is adopted by a novel method.The results of Matlab simulation show that the improved control scheme effectively reduced the supply current harmonic and THD. Compared with the traditional filtering methods, the novel improved control scheme has better dynamic performance.With the theoretically analysis above, the hardware and software of experiment system are designed, including the capacitance of the DC-side, the inductance of the AC-side and the design of the secondary filter circuit. Put the emphasis on the control circuit of TMS320F2812 and its related circuits such as signal adjustment, protection, phase-lock loop, switch drive and its buffer circuit. About the software, the design control flow of it is realized; especially expounding the digital PI control.Based on the theory and research, a single-phase voltage four-quadrant rectifier test-bed is constructed with DSP TMS320F2812. The unity power-factor simulation and feedback experiment are designed. The experimental results demonstrate the accuracy of the designed experimental system, which adopts the transient current control, the predictive current control and the improved design of both.