Research On A Novel Portable Bidirectional Energy Storage Power Supply Grid-Side Harmonic Suppression Strategy

With the increasing demand for outdoor electricity such as medical rescue,disaster relief,and outdoor exploration,a portable energy storage power supply that can operate stably is urgently needed.However,traditional unidirectional energy storage power supplies can only achieve unidirectional energy flow,requiring two independent unidirectional converters to complete charging and discharging,resulting in large volume and high cost of portable energy storage power supplies.In response to the above issues,bidirectional energy storage converters exhibit broader research value and industrial application prospects due to their advantages of bidirectional power flow,small size,and high converter utilization.Therefore,bidirectional energy storage converters can be applied in the new generation of portable bidirectional energy storage power supply products.This thesis has developes a portable bidirectional energy storage power supply and proposes a feedback control based grid side harmonic suppression strategy to address the problem of high grid side current harmonics in converters.This strategy can simultaneously suppress the impact of DC bus voltage second harmonic fluctuations and the third voltage harmonics in the grid voltage on the input current of the converter.This thesis also adopts a DC bus voltage double frequency ripple compensation algorithm,which can suppress the impact of DC bus voltage double frequency ripple on the current loop,accelerate the response speed of the voltage loop,thereby reducing the voltage overshoot value and adjustment time.The results of this thesis have been applied to industrial projects.This thesis first describes the development history of portable bidirectional energy storage converters,analyzes and compares the topology and control strategies,and clarifies the advantages of using single-phase PWM rectifiers in the front stage and bidirectional LLC resonant converters in the rear stage.Then,this thesis analysis the topology and working mode of the portable bidirectional energy storage converter.The reasons for grid side harmonics are analyzed in detail.The closed-loop controller of the portable bidirectional energy storage converter is designed,and the proposed harmonic suppression strategy based on feedback control and the DC bus voltage double frequency ripple compensation algorithm used are analyzed,And the feasibility and superiority of the two control algorithms are verified through simulation.Finally,a 2kW prototype is built to further verify the feasibility of the feedback control based harmonic suppression strategy by comparing the harmonic content of the grid side current.And compared with the technical parameter table,the various performance indicators of the prototype are tested to meet the engineering application indicators.