| With the rapid development of our country’s electric power system, the modern power load is moving toward the direction that its type is more and more complex and its capacity is increasing, attendant for power quality issues are also receiving more and more attention by both the power supply and user, but only after the fundamental understanding of the nature of how power quality disturbances occur that we can take active and effective measures to it, so for power quality disturbances generating problems study is very important.This article is in view of the development of controlled current quality disturbances generator, proposing a main circuit topology form based on cascaded H-bridge modules and differentiation structure of high frequency and low frequency modules, it can effectively simulate various current quality disturbances, besides this circuit rectifier side can take energy from the system, so this device can also has the function generating active power disturbances.This paper uses PSCAD/EMTDC as simulation platform, builds a simulation model of main circuit and control strategy, the modulation strategy is using unipolar times frequency and carrier phase-shift SPWM form, simulates the various disturbances generating strategies proposed in the third chapter, including single current quality disturbances such as harmonic current, current fluctuation, three-phase unbalance current, power factor disturbance and compound current quality disturbances generating strategies. Eventually we develop a400V/100kVA laboratory low-voltage prototype, its human-computer interaction systems is established by using LabVIEW software, the primary control system is consists of DSP+FPGA and rock-bottom CPLD. All control algorithms of the device are written in VHDL language and realized in the FPGA. Theoretical simulation and prototype experimental results are certification that the research on compound current quality disturbances generator in this article is feasible and correct. |
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