Research And Design Of A Three Level Three Phase High Power Factor Rectiifer Based On DSP

Multi-level PWM rectifier with the advantages of its low voltage in the switchingdevice requirements and the harmonic content in the same switching frequency muchsmaller than the two-level rectifier content, has become a power electronic devices inthe high-voltage high-power applications research focus. According to the neutralpoint clamped three-level converter topology having many power devices and leadingto the bridge arm straight easily, etc. From a security and economic point of view, thispaper studies three-phase three-switch three-level (VIENNA) rectifier as the objectwith an in-depth introduction in terms of topology, operating principle, controlalgorithms. Simulation and experiment show that VIENNA rectifier can run on theunit power factor with less power devices.This paper analyzes the the VIENNA topologies, and then achieves thedecoupling current control through the introduction of current fed in the dq statemathematical model, which established the dual closed-loop control block diagrambased on PI regulators. This paper gives a in-depth study of three-level space vectormodulation(SVPWM) algorithm, and on this basis to improve it and complete thetransform of three-level space vector synthesis to two-level space vector synthesis,which greatly simplify the vector synthesis of complex and easily to realize the digitalcontrol. At last it verifies the validity of the method by simulation.On the basis of the above work, the paper completes the three-phase VIENNArectifier power circuit and digital control system design based on a floating-point DSP.It gives the program flow chart of the simplified three-level space voltage vectorsynthesis algorithm, and designes a set of20KW experimental prototype. Test resultsand waveforms show that: the VIENNA rectifier under the dual-loop control strategybased on simplified SVPWM algorithm has low harmonic content, high power factor,good dynamic steady-state performance characteristics, and reflects a big advantagein the suppression of fluctuations in the middle point potential.