A Wide-Voltage Isolated DC-DC Converter with Automatic Current Limiting Function

Abstract

The invention discloses a wide-voltage isolated DC-DC converter with an automatic current limiting function, which includes two half-bridge circuits, two sets of LLC resonant cavities, two sets of voltage clamping diode pairs, and two synchronous conversion ratio Isolation transformer and three-phase bridge circuit; Among them, the two half-bridge circuits are connected to their respective input power supplies, the primary side of the isolation transformer is respectively connected to one end of the resonant inductor of the corresponding LLC resonant cavity and the neutral point of the half-bridge circuit, and the other end of the resonant inductor is connected to 2 The center point of a split resonant capacitor, the voltage clamping diode is connected in parallel with the split resonant capacitor; the secondary side of the isolation transformer is connected in series with reverse polarity, and the three nodes of the transformer group are respectively connected to the neutral point of the three-phase bridge circuit after series connection; The invention utilizes the advantages of LLC frequency conversion and voltage regulation, combined with PWM pulse 180º phase shift to realize fast switching between series and parallel, realizes fast adjustment of rated voltage and 2 times rated voltage output, and has the advantages of small switching loss, high efficiency and simple structure.

Description

technical field

[0001] The invention relates to a wide-voltage isolated DC-DC converter with an automatic current limiting function, belonging to the technical field of converters. Background technique

[0002] The DC system is a very important part of the substation. Its main task is to provide power for relay protection devices, circuit breaker operations, and various signal circuits. The normal operation of the DC system is related to the correct operation of relay protection and circuit breakers, which will affect the safe operation of substations and even the entire power grid. At present, the voltage levels commonly used in substations are 110V and 220V. However, due to the large variation range of the two levels of voltage, it is difficult to design especially for the isolated DC-DC converter. Therefore, starting from the actual universal requirements of substations, it is an urgent problem to develop converters that meet the DC bus requirements of substations with ...

Examples

Embodiment Construction

[0043] The present invention will be further described below. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.

[0044] see figure 1 , the present invention provides a wide-voltage isolated DC-DC converter with automatic current limiting function, including 2 half-bridge circuits, 2 groups of LLC resonant cavities with split arrangement of resonant capacitors, 2 groups of voltage clamping diode pairs, 2 an isolation transformer and a three-phase bridge circuit with the same transformation ratio;

[0045] The structure is as follows:

[0046] The two half-bridge circuits are respectively connected to the respective input power supplies; the first half-bridge circuit includes 2 MOSFET tubes SA1-SA2; the second half-bridge circuit includes 2 MOSFET tubes SB1-SB2.

[0047]The first LLC resonant cavity circuit includes resonant inductance LrA, resonant ...

technical field

[0001] The invention relates to a wide-voltage isolated DC-DC converter with an automatic current limiting function, belonging to the technical field of converters. Background technique

[0002] The DC system is a very important part of the substation. Its main task is to provide power for relay protection devices, circuit breaker operations, and various signal circuits. The normal operation of the DC system is related to the correct operation of relay protection and circuit breakers, which will affect the safe operation of substations and even the entire power grid. At present, the voltage levels commonly used in substations are 110V and 220V. However, due to the large variation range of the two levels of voltage, it is difficult to design especially for the isolated DC-DC converter. Therefore, starting from the actual universal requirements of substations, it is an urgent problem to develop converters that meet the DC bus requirements of substations with ...

Examples

Embodiment Construction

[0043] The present invention will be further described below. The following examples are only used to illustrate the technical solution of the present invention more clearly, but not to limit the protection scope of the present invention.

[0044] see figure 1 , the present invention provides a wide-voltage isolated DC-DC converter with automatic current limiting function, including 2 half-bridge circuits, 2 groups of LLC resonant cavities with split arrangement of resonant capacitors, 2 groups of voltage clamping diode pairs, 2 an isolation transformer and a three-phase bridge circuit with the same transformation ratio;

[0045] The structure is as follows:

[0046] The two half-bridge circuits are respectively connected to the respective input power supplies; the first half-bridge circuit includes 2 MOSFET tubes SA1-SA2; the second half-bridge circuit includes 2 MOSFET tubes SB1-SB2.

[0047]The first LLC resonant cavity circuit includes resonant inductance LrA, resonant ...

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