Abstract: An energy storage converter and an energy storage system are provide. The energy storage converter includes: a DC switching power supply circuit configured to provide a first power supply using DC power from the DC side port; an AC switching power supply circuit configured to provide a second power supply using AC power from the AC side port; a power supply circuit configured to supply power to the energy storage converter using the first power supply or the second power supply; and a control circuit configured to, based on an operation state of the energy storage converter, control the DC switching power supply circuit or the AC switching power supply circuit to provide the power supply circuit with power supply. A power supply mode is selected based on an operation state of the energy storage converter. The DC/AC switching power supply circuit independently supplies power at the same time.

Abstract: A fault detection method and a fault protection method for a power conversion system, and a power conversion system are provided, which relate to the technical field of fault detection for circuits. The fault detection method includes: controlling, when the power conversion system operates in a reactive mode, an alternating current pre-charge power supply to operate to charge a bus capacitor of the power conversion system, where the bus capacitor supplies power to a digital signal processor (DSP) through a first switch power supply (SPS), determining whether the DSP is energized to obtain a first determination result, and determining that the bus capacitor is short-circuited if the first determination result indicates that the DSP is de-energized. According to the present disclosure, when the bus capacitor of the power conversion system is short-circuited, the short-circuit fault of the bus capacitor can be detected.

Abstract: A power conversion system, an energy storage system and a power supply method are provided. The power conversion system includes a battery management system and an auxiliary power supply. A positive electrode of the auxiliary power supply is connected to a positive electrode of a battery rack. The auxiliary power supply is configured to obtain power from the battery rack, convert the power obtained from the battery rack, and supply the converted power to the battery management system and a load in the power conversion system. The battery management system is configured to sample a voltage of the battery rack and a current of the battery rack, and control charging and discharging of the battery rack based on the voltage and the current.

Abstract: A preparation method of eicosapentaenoic acid (EPA) ethyl ester is provided and relates to the field of EPA ethyl ester processing technologies. The preparation method includes: performing degumming and deacidification on a sardine crude oil to obtain a semi-refined sardine oil, performing esterification on the semi-refined sardine oil to obtain an esterified sardine oil and then performing winterization on the esterified sardine oil to thereby obtain an semi-refined esterified sardine oil, performing bleaching and deodorization on the semi-refined esterified sardine oil, and performing multi-stage distillation treatment. Finally, the sardine oil is purified by liquid chromatography to obtain the high purity EPA ethyl ester. The preparation method can improve a utilization rate of the sardine oil and obtain the high-purity EPA ethyl ester.