Fuel cell uninterrupted power supply device

Abstract

The invention discloses a fuel cell uninterrupted power supply device, which comprises a main circuit and a control system, wherein the main circuit comprises a by-pass switch, a three-phase four-wire rectifier, a three-phase four-wire inverter, a fuel cell, a direct current to direct current converter, a bidirectional direct current to direct current converter and a super capacitor stack, wherein the control system comprises a direct current bus voltage detection section, a super capacitor stack voltage control section, a two direct current bus input and output side current detection section, a two inner loop current control section and a direct current bus center voltage balance control section. In the device, the bidirectional direct current to direct current converter and the super capacitor stack provide middle and low frequency alternating current components of a direct current bus current and the positive and negative direct current bus voltages are controlled to be balance to effectively suppress the low-frequency pulse of the positive and negative direct current bus voltages when a power grid is asymmetric or the three phases of a load are unbalance, so that the reliability and the service life of the fuel cell uninterrupted power supply system are free from the limitations of the reliability and the service life of an electrolytic capacitor and the reliability and service life of the uninterrupted power supply device are improved.

Description

technical field [0001] The invention relates to an uninterruptible power supply device, especially an uninterruptible power supply device using a fuel cell as a backup power supply. Background technique [0002] An uninterruptible power supply device using a fuel cell as a backup power source has the advantages of long backup time, high reliability, and environmental protection compared with an uninterruptible power supply device using a battery as a backup energy source. The current fuel cell power generation system has poor dynamic characteristics due to the performance constraints of mechanical links in the system. When the uninterruptible power supply is switched from the grid power supply to the fuel cell power supply and when the load is suddenly changed under the fuel cell power supply state, the dynamic performance of the fuel cell is difficult to meet the power supply requirements of the load, and the rapid power supply change will affect the service life of the fue...

AI Technical Summary

Problems solved by technology

The practice of using larger capacitors will lead to larger volume and weight of the system, and the capacitors applied to this higher voltage and larger capacitance are usually electrolytic capacitors, which brings poor reliability and short life. and other issues; and if the method of adding an additional switch bridge arm will increase the system cost

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