Research On Z-Source Rectifier

With the development of energy conversion technology, the PWM rectifier has attention much focus in the field of power electonics. Because of the function of harmonic elimination and power factor correction, the PWM rectifier can be used as an ideal network between equipment and power system.A voltage source rectifier (VSR) can only obtain higher DC votage than AC voltage, which lead that motor must stand the high DC voltage during start course, and the modulation index of the inverter has to be setted in a low value, which reduces the quality of output AC voltage. Furthermore, In a VSR, the upper and lower devices of each phase leg could be gated simultaneously by EMI noises, which would destroy the circuit and decrease the reliability. To avoid the shoot-through, the method of increase dead time has been applied. It would result in the distortion of the current waveform.In this thesis, a novel rectifier named as Z-source rectifier is presented. It makes the shoot-through state possible, which avoids the possibility of ruin by EMI noises. And the shoot-through state allows the Z-source rectifier to buck and boost its output voltage.The thesis analyses the operating principle and control strategy of the Z-source rectifier. Based on the analysis, the design of a prototype of 5kw three-phase Z-source rectifier has been described in detail. The circuit design, especially the inductors and capacitors of Z-network, has been discussed. So do the control strategy and system. The simulation and optimization of parameter have been fulfilled with "Saber" software. Then the prototype model has been designed by "Unigraphicsand" software. At last the experimental and simulation results have been performed to confirm the ananlysis, which are quite consistent with the theoretical analysis.