US-20260128683-A1 - HIGH-VOLTAGE HIGH-SPEED SWITCHING APPARATUS FOR STABILIZING VOLTAGE OF HYDROGEN FUEL CELL AND CONTROL METHOD THEREOF

US20260128683A1US 20260128683 A1US20260128683 A1US 20260128683A1US-20260128683-A1

Abstract

A high-voltage high-speed switching apparatus includes a hydrogen fuel cell; an inverter configured to convert a DC voltage outputted from the hydrogen fuel cell into a three-phase AC voltage of a predetermined level; a voltage divider connected in parallel between output terminals of the hydrogen fuel cell and input terminals of the inverter; a switching control unit configured to compare an input voltage of the voltage divider and predetermined DC voltage reference values, and generate and output a plurality of switching control signals; a high-speed switching unit including first to mth switching channels that are connected in parallel to the voltage divider, each of the first to mth switching channels being controlled by a plurality of switching control signals to be switched; and a dummy load group configured with dummy loads that are independently connected to the first to mth switching channels, respectively.

Inventors

Min Soo JANG
Kyung Choon LEE
Won Young JE
Tae Min JANG

Assignees

DESTIN POWER CO., LTD.

Dates

Publication Date: 20260507
Application Date: 20251016
Priority Date: 20241105

Claims (7)

1 . A high-voltage high-speed switching apparatus for stabilizing the voltage of a hydrogen fuel cell, the apparatus comprising: a hydrogen fuel cell; an inverter configured to convert a DC voltage outputted from the hydrogen fuel cell into a three-phase AC voltage of a predetermined level; a voltage divider connected in parallel between output terminals of the hydrogen fuel cell and input terminals of the inverter; a switching control unit configured to compare an input voltage of the voltage divider and predetermined DC voltage reference values, and generate and output a plurality of switching control signals; a high-speed switching unit including first to mth switching channels that are connected in parallel to the voltage divider, each of the first to mth switching channels being controlled by a plurality of switching control signals to be switched; and a dummy load group configured with dummy loads that are independently connected to the first to mth switching channels, respectively.
2 . The high-voltage high-speed switching apparatus according to claim 1 , wherein the voltage divider includes first and second capacitors that are connected in parallel between the output terminals of the hydrogen fuel cell and the input terminals of the inverter and are connected in series to each other, and one end of the first capacitor and one end of the second capacitor are connected to a central node to be grounded, the other end of the first capacitor is connected to a P node, and the other end of the second capacitor is connected to an N node.
3 . The high-voltage high-speed switching apparatus according to claim 2 , wherein each of the first to mth switching channels includes a top leg switching element section and a bottom leg switching element section that are connected in series, and one end of the top leg switching element section and one end of the bottom leg switching element section are connected to the central node to be grounded, the other end of the top leg switching element section is connected to the P node, and the other end of the bottom leg switching element section is connected to the N node.
4 . The high-voltage high-speed switching apparatus according to claim 3 , wherein the switching control unit simultaneously or selectively switches the first to mth switching channels depending on the level of an overvoltage outputted from the hydrogen fuel cell so that a load current amount flowing through the dummy load group is made the same or different depending on a time.
5 . The high-voltage high-speed switching apparatus according to claim 4 , wherein when a voltage outputted from the hydrogen fuel cell is higher than a first DC voltage reference value, the switching control unit performs turn-on operations simultaneously for the first switching channel to the mth switching channel, when a voltage outputted from the hydrogen fuel cell is higher than a second DC voltage reference value that is lower than the first DC voltage reference value, the switching control unit performs a turn-on operation for the first switching channel, and when a voltage outputted from the hydrogen fuel cell is still higher than the second DC voltage reference value after a set predetermined delay time, the switching control unit performs a turn-on operation for the second switching channel, and when a voltage outputted from the hydrogen fuel cell is lower than a third DC voltage reference value, the switching control unit performs a turn-off operation for the mth switching channel, and when a voltage outputted from the hydrogen fuel cell is still lower than the third DC voltage reference value after a set predetermined delay time, the switching control unit performs a turn-off operation for an (m−1)th switching channel.
6 . A method for controlling a high-voltage high-speed switching apparatus for stabilizing the voltage of a hydrogen fuel cell, including a hydrogen fuel cell; an inverter configured to convert a DC voltage outputted from the hydrogen fuel cell into a three-phase AC voltage of a predetermined level; a voltage divider connected in parallel between output terminals of the hydrogen fuel cell and input terminals of the inverter; a switching control unit configured to compare an input voltage of the voltage divider and predetermined DC voltage reference values, and generate and output a plurality of switching control signals; a high-speed switching unit including first to mth switching channels that are connected in parallel to the voltage divider, each of the first to mth switching channels being controlled by a plurality of switching control signals to be switched; and a dummy load group configured with dummy loads that are independently connected to the first to mth switching channels, respectively, wherein the switching control unit simultaneously or selectively switches the first to mth switching channels depending on the level of an overvoltage outputted from the hydrogen fuel cell so that a load current amount flowing through the dummy load group is made the same or different depending on a time.
7 . The method according to claim 6 , wherein when a voltage outputted from the hydrogen fuel cell is higher than a first DC voltage reference value, the switching control unit performs turn-on operations simultaneously for the first switching channel to the mth switching channel, when a voltage outputted from the hydrogen fuel cell is higher than a second DC voltage reference value that is lower than the first DC voltage reference value, the switching control unit performs a turn-on operation for the first switching channel, and when a voltage outputted from the hydrogen fuel cell is still higher than the second DC voltage reference value after a set predetermined delay time, the switching control unit performs a turn-on operation for the second switching channel, and when a voltage outputted from the hydrogen fuel cell is lower than a third DC voltage reference value, the switching control unit performs a turn-off operation for the mth switching channel, and when a voltage outputted from the hydrogen fuel cell is still lower than the third DC voltage reference value after a set predetermined delay time, the switching control unit performs a turn-off operation for an (m−1)th switching channel.

Description

BACKGROUND 1. Technical Field The present disclosure relates to a high-voltage high-speed switching apparatus for stabilizing the voltage of a hydrogen fuel cell and a control method thereof, and more particularly, to a high-voltage high-speed switching apparatus for stabilizing the voltage of a hydrogen fuel cell and a control method thereof, which safely maintain voltage in a hydrogen fuel cell system to protect a power conversion device and a fuel cell from an overvoltage. 2. Related Art A hydrogen fuel cell system uses hydrogen to generate power, and generally includes a fuel cell stack in which a plurality of fuel cells are stacked. In order to prevent damage to the fuel cells and a power conversion device when a voltage excessively increases in the fuel cell stack, a protection system is required. In particular, when there is an open circuit voltage (OCV) in the fuel cell stack, the performance and lifespan of the fuel cells may decrease. According to a conventional apparatus for converting power of a fuel cell for power generation illustrated in FIG. 1 (FIG. 2 of Korean Patent Laid-open Publication No. 10-2023-0123573), the apparatus includes a fuel cell 101, a first initial charge circuit 102, a dummy resistor 103, a DC input breaker 104, a power converter 106, a filter unit 107, an AC system breaker 108, a second initial charge circuit 109, and a system 110. The apparatus for converting power of a fuel cell for power generation includes a power converter configured to convert power generated by the fuel cell and supply the converted power to a system or load, and a controller configured to detect a failure occurring in the fuel cell, the power converter or the system or load while the fuel cell is driven and to reduce an open circuit voltage (OCV) of the fuel cell by a dummy resistor connected in parallel to output terminals of the fuel cell when a failure occurs in the fuel cell, the power converter or the system or load. However, in the hydrogen fuel cell system that outputs a high voltage, because a maximum DC voltage is very high as 1,500 volts, simply connecting the dummy load as an existing chopper type configuration as in FIG. 1 cannot stabilize an overvoltage, and energy loss may be caused. PRIOR ART LITERATURES Patent Documents Korean Patent Laid-open Publication No. 10-2023-0123573 entitled “Apparatus for Converting Power of Fuel Cell for Power Generation and Method thereof”Korean Patent Laid-open Publication No. 10-2023-0109977 entitled “Grid-connected Inverter for Supporting Uninterruptible Power Supply Mode”Korean Patent Laid-open Publication No. 10-2014-0041156 entitled “Power Conversion Device”Korean Patent Laid-open Publication No. 10-2012-0061661 entitled “Fuel Cell System and Method for Controlling the Same” SUMMARY An object of the present disclosure is to provide a high-speed switching apparatus and a control method thereof capable of stabilizing the high voltage of a hydrogen fuel cell by separately controlling the positive terminal side and the negative terminal side of a dummy load. In an embodiment, a high-voltage high-speed switching apparatus for stabilizing the voltage of a hydrogen fuel cell may include: a hydrogen fuel cell; an inverter configured to convert a DC voltage outputted from the hydrogen fuel cell into a three-phase AC voltage of a predetermined level; a voltage divider connected in parallel between output terminals of the hydrogen fuel cell and input terminals of the inverter; a switching control unit configured to compare an input voltage of the voltage divider and predetermined DC voltage reference values, and generate and output a plurality of switching control signals; a high-speed switching unit including first to mth switching channels that are connected in parallel to the voltage divider, each of the first to mth switching channels being controlled by a plurality of switching control signals to be switched; and a dummy load group configured with dummy loads that are independently connected to the first to mth switching channels, respectively. Preferably, the voltage divider may include first and second capacitors that are connected in parallel between the output terminals of the hydrogen fuel cell and the input terminals of the inverter and are connected in series to each other. One end of the first capacitor and one end of the second capacitor may be connected to a central node to be grounded, the other end of the first capacitor may be connected to a P node, and the other end of the second capacitor may be connected to an N node. Preferably, each of the first to mth switching channels may include a top leg switching element section and a bottom leg switching element section that are connected in series. One end of the top leg switching element section and one end of the bottom leg switching element section may be connected to the central node to be grounded, the other end of the top leg switching element section may be connected to the P node, and t