Research And Realization Of Voltage Quality Disturbance Generator

Power quality control devices must be testified after their manufacturing. Power quality analysis theories and power quality analyzers must be inspected, while researching power quality. Voltage quality distrubance generator can simulate many types of power quality problems, and provide fundamental platform for the measurement, analysis, evaluation and control of grid’s power quality, which is advantageous to deepen research on all types of voltage disturbance problems.This issue proposes a voltage quality distrubance generator based on H cascade and multilevel structure. Every phase of the device contains4back-to-back H power modules, which adopt multiplex cascade technology. The inverter side connects the system directly without series transformer.As to the generation of overvoltage, undervoltage, voltage swell and sag, the device runs in the way of reference voltage feedforwarding and inverter output voltage feedbacking. As to the generation of harmonic voltage and unbalance voltage, the device adopts open-loop control stratigy with phase locked by system voltage. Simulation analysis of the disturbances above is based on PSCAD to testify the efficiency of the device structure, main parameters and control stratigies. The controller of the device contains3layers:host computer, DSP+FPGA and bottom CPLD. The control stratigies are realized in FPGA.This issue concludes3types of transformers, and analyzes the sags corresponding to4types of short circuit, including three-phase faults, single-phase faults, two-phase faults and two-phase-to-ground faults, two types of load accessment, including star-connection and delta-connection, and3types of transformers. Seven types of sags are obtained and realized in device.Finally, a100kVA/400V low voltage voltage quality distrubance generator is created. The experiment result proves that the proposed main circuit topology and control strategies are efficient.