Composite circulating current suppression method and device for shore power supply system

Abstract

A compound circulation suppression method and device for a shore power supply system can solve the circulation problem in a parallel system of shore power supply. The compound circulation suppression method includes a circulation suppression method based on the combination of average current control and centralized control, which controls the amplitude, frequency and phase of the shore power supply output voltage through the control method of current sharing during the control process; centralized control By coordinating the controllers, the modulation waves of the dq coordinate system are uniformly generated and sent to the central controllers of each variable frequency power supply, and each central controller receives the dq axis modulation waves U md , U mq After dividing by the average value of the DC bus voltage of each variable frequency power supply, it is superimposed with the compensation amount generated by the current sharing control to achieve the purpose of suppressing the circulation of the parallel shore power system. The stable operation of the shore power supply system is guaranteed, and the invention is simple to implement, and has the advantages of low cost, high reliability, easy capacity expansion, and the like.

Description

technical field [0001] The invention relates to the technical field of shore power, in particular to a compound circulation suppression method and device for a shore power power supply system. Background technique [0002] Due to the limitation of the power of power semiconductor devices, the power level that can be achieved by a single shore power variable frequency power supply device is difficult to adapt to high power level applications. Therefore, in high power applications, shore power supply devices are generally used in parallel to improve the system. Capacity and redundancy; at the same time, this parallel method is simple and easy to expand, so it has been widely researched and applied. [0003] Shore power supplies are connected in parallel to output AC voltage. To achieve parallel operation of two or more shore power supplies, the frequency, phase, amplitude and internal resistance of the output voltages of each device are exactly the same, so that the output cur...

AI Technical Summary

Problems solved by technology

[0004] Circulation suppression methods include hardware elimination method and software control method. The hardware circulation elimination method can prevent the generation of the circulation path on the hardware, and it is usually realized by adding an isolation transformer at the output port of each parallel-connected shore power variable frequency power supply device, but this will Resulting in a larger size and weight for the shore power system

It is also possible to suppress the circulating current through the series reactor at the output end of the shore power supply unit. The series reactor can provide high impedance for each shore power supply unit to suppress the circulating current, but this method is not ideal for suppressing low-frequency circulating current, and Because the impedance is increased, the output voltage drop of the shore power supply is increased, and the energy conversion efficiency is reduced.

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