Research And Implementation Of Three Phase Current Source Rectifier

The harmonic and power factor (PF) are the major power quality problems, to which thesolution is one of the important research fields in power electronics. PWM rectifier, as one ofpower factor corrrection (PFC), overcomes the drawbacks of traditional rectifier, likeunidirectional power flow, poor PF, high THD, bad controllability, etc. It has been applied invarious fields of national economy. According to output characteristics, voltage source rectifier(VSR) and current source rectifier (CSR) are two main types of PWM rectifier. And CSR wasdeveloped later than VSR. But nowadays with the development of device, modulation and control,the CSR, with the inherent ability of limiting short current, is widely employed in motor drive,SMES, pulse power supply, induction heating, new energy power generation, etc. In order toconform to this trend, this thesis studies three phase CSR and its control strategies, etc.Firstly, the topology essence of CSR and VSR are analyzed and its derivation process ispresented. Moreover, the operation principle of CSR is analyzed from the direction of controlobject. Based on the mathematical model founded in dq coordinate, the CSR’s static characteristicis also derived, and the inherent operation rules are summarized from static characteristic. Inaddition, by analyzing the driver signal generation and device stress, some conclusions are drawnincluding the design method of driver signal generation, the design basis of snubber circuit, andthe loss distribution of power semiconductor devices, etc.Secondly, this thesis focuses on study and simulation of CSR’s PF operation ability and activedamping (AD) control. Many elements relate to the PF operation ability, not only including theload type and size, modulation ratio, load current and LC filter parameters but control strategy. Byusing MATLAB, the PF operation ability order of four kinds of control strategy is obtained. AboutAD control,16kinds of AD control based on virtual impedance are proposed from the filteringand damping characteristics of all passive damping schemes, and their features and generalities areconcluded. The proposed AD controls are validated by simulation. Furthermore, it is concludedthat the law between PF operation ability and passive damping schemes, feedback variables,damping resistance.Finally, a3kW three phase CSR prototype is developed, and a novel way of achievingoverlap time is proposed to obtain higher accuracy. Based on the experimental system, three phaseCSRs open-loop state, closed-loop state and dynamic process are tested. Steady-state experimentalresults summarized from the closed-loop test verify the theoretical study of this thesis.