Research On Principle And Control Method For The Combination Of Micro-grid Storage Unit And Active Power Filter

As a supplement of large-scale power grid, Micro-grid plays a moreand more important role in power system. But with numerous ofnonlinear power electronic members coming into the Micro-grid, thepower quality is seriously polluted. In order to solve the problem ofmicro-grid power quality with no additional cost, the storage unit fromMicro-grid is made into a combination with active power filter. Thispaper focuses on the research of principle and control method of thecombination device.Analysis of the structural characteristics of the active power filterand storage unit from Micro-grid, gave the principles, analysis andcomparison of the similarities between them, further proposed thestructure of the combined device. Gave the combination device functionslike reactive power compensation, harmonic suppression and UPSfunction, also the device working model, demonstrated the feasibility ofcombined device as a multi-functional machine. The device could notonly be achieved the energy storage unit functions, but also play thepower quality regulator of APF function.Paper researched the control method of the combination. Created themathematical model of DC-DC converter, power limiting element wasadded into the conventional control to ensure stable operation of thestorage unit. Created the mathematical model of DC-AC converter,studied the inverter control strategy in UPS mode and grid-connectedmode, proposed the control strategy based on composite correctiontechnology of improved triangle wave comparison to achieve theeffective control in grid-connected mode. Studied the device currentinstruction synthesis and output current limiting. Proposed the predictivecontrol with feedforward correction, achieve effective control of the DCbus voltage. Designed the total controller of the device, realized thecontrol of multi-objective optimization. Design the phase-locked loop. Bythe research of control method, designed software flow chart based onDSP+FPGA systems.In order to verify the feasibility of the combination device and control method, simulation and experiment were researched in detail. Theresults show that, the device can not only be achieved the energy storageunit functions, but also played the power quality regulator of APFfunction, provided a novel and low cost method to solve the powerquality problems of Micro-grid.