Simulation And Design Of Cascade H Bridge In Reactive Power Compensation

Electricity is a significant energy for human beings. However as science and technology advance nowadays, lots of electrical equipment have been added to the electricity grid. Therefore, a lot of problems have been caused, including a large number of energy wastes due to reactive current. So it’s time to take action to reduce the reactive current. This paper aims to discuss how to compensate the reactive current on the high pressure side of grid so as to improve the power factor, and study the multilevel reactive power generator based on the cascaded H Bridge. And the simulation method is applied to find out its features.This paper first introduces the harm of reactive current and the significance of doing reactive current compensation, and then all kinds of reactive power generators are classified and compared specifically. By introducing all the types of the multilevel reactive compensation generators, this paper targets at finding out their respective advantages and disadvantages. After the comparing, this paper finally took the cascade H bridge multilevel reactive power generator as the object of study in this paper.In order to get a minimum harmonic content and comprehensively optimal multilevel modulation mode, this paper employs the Simulink module of Matlab software to establish several the simulation models. And this paper finally chooses times frequency CPS-SPWM technology as cascade H bridge modulation mode after analysis and comparison.Then this paper does some simulation detection on the reactive current based on the instantaneous reactive power algorithm so as to improve this algorithm and put forward a method called the double transformation to get the current of base wave reactive. Furthermore, this paper proposes a three phrases balance method to control the phase equilibrium for the capacitor voltages of dc side, which turns out can effectively avoid the unbalanced phenomena between the three alternate voltages and reduce the harmonic generation, and is of great significance for achieving the ideal compensation.As to the hardware part of this research, TMS320F2812digital signal processor made by TI Company is applied to control circuit and construct the system module. And FPGA from Altera Company is employed to produce controlling signal of the H Bridge; as to the software part, this research uses the CCS and QUARTUS II design system as platforms to program DSP and FPGA. All the software is modular constructed so as to realize a dynamic and quick control.