A low voltage and high current bidirectional DC / DC power supply that can be connected in parallel

Abstract

The present invention discloses a low-voltage, high-current, bidirectional DC / DC power supply that can be connected in parallel, which is applied to a high-power driving power supply of an electric forklift. The power demand for the power supply varies according to the size of the forklift. Therefore, for forklifts with different power level requirements, the demand can be met by expanding the capacity by connecting the power supply in parallel. In addition, from the perspective of energy saving, the kinetic energy of the forklift and the gravitational potential energy of the workbench can be fed back to the power supply battery during the braking of the forklift or the descent of the workbench, so the power flow of the forklift driving power supply needs to achieve bidirectional flow. The low-voltage, high-current, bidirectional DC / DC power supply that can be connected in parallel in the present invention has a single-module power level of 6kW, can achieve high-efficiency operation, high power density, small size and light weight, and has a CAN communication interface. According to the requirements of forklifts with different power levels, multi-module parallel operation can be achieved, and each module is coordinated and controlled through communication.

Description

Technical Field

[0001] The invention discloses a low-voltage and high-current bidirectional DC / DC direct current power supply which can be connected in parallel and belongs to the technical field of energy. Background Art

[0002] Due to the increasingly serious environmental pollution problem, exhaust gas from various diesel and gasoline locomotives is one of the main causes of air pollution. Due to the high power level of high-power forklifts, the original diesel or gasoline forklifts will release a large amount of exhaust gas to pollute the environment when working. In recent years, with the development of battery technology, the concept of electric forklifts has gradually become a reality. This application is a high-power drive power supply for electric forklifts. The power demand for the power supply varies according to the size of the forklift. Therefore, for forklifts with different power level requirements, the capacity expansion can be achieved by connecting the power supply in parallel to meet the needs. In addition, from the perspective of energy saving, the kinetic energy of the forklift and the gravitational potential energy of the workbench can be fed back to the power supply battery during the forklift braking or the lowering of the workbench, so the power flow of the forklift drive power supply needs to achieve bidirectional flow. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention provides a low-voltage and high-current bidirectional DC / DC power supply that can be connected in parallel, comprising: an air switch K1, an input processing circuit board B1, a three-way parallel circuit board B2, a three-way parallel inductor L1-L3, an output processing circuit board B3, a control board B4, an auxiliary power board B5, a display circuit board B6, a chassis shell W, a radiator S, a cooling fan F1, a cooling fan F2, an inlet aviation plug interface P1, an outlet aviation plug interface P2, and a communication interface T1, characterized in that: a cooling fan F1 and a heat sink are provided inside the rear side of the shell W. Fan F2 and an incoming line aviation plug interface P1 and an outgoing line aviation plug interface P2, the incoming line aviation plug interface P1 is the high-voltage side input terminal DCin+ and DCin-, the incoming line aviation plug interface P1 is connected to the air switch K1, and then connected to the lightning protection circuit of the input processing circuit board B1, the output of the lightning protection circuit is connected to the high-voltage side pre-charging link in the input processing circuit board B1, the output of the high-voltage side pre-charging link of the input processing circuit board B1 is connected to the high-voltage side sampling circuit of the three-way parallel circuit board B2, the high-voltage side sampling circuit is connected to the input filter capacitor C1, the The positive and negative ends of the filter capacitor C1 are connected to a three-way parallel chopper circuit, and the three-way parallel chopper circuit is connected to the three-way parallel inductor L1~L3 on the output side, and the three-way parallel inductor L1~L3 is connected to the three-way fuse FU3~FU5 of the output processing circuit board B3, and the three-way fuse is connected to the three-way current detection shunt FL1~FL3, and the output sides of the three-way current detection shunt FL1~FL3 are connected together, through the output filter capacitor C2, the positive electrode of the output filter capacitor C2 is connected to the low-voltage side pre-charging link, and the low-voltage side pre-charging link passes through the varistor RV4 and then passes through the output side. After sampling the voltage-dividing resistors R3 and R4, they are connected to the output terminals DCout+ and DCout-. The power supply circuits DLfan of the cooling fan F1 and the cooling fan F2 are connected to the output terminals DCout+ and DCout- respectively, wherein DCout+ is connected to the positive terminals of the cooling fan F1 and the cooling fan F2 after passing through the temperature control switch St in the power supply circuits DLfan of the cooling fan F1 and the cooling fan F2, and DCout- is directly connected to the negative terminals of the cooling fan F1 and the cooling fan F2. The front chassis panel of the outer casing W is provided with a display circuit board B6 and a communication interface T1.

[0004] As a preferred embodiment of the present invention, the incoming line aviation plug interface P1 and the outgoing line aviation plug interface P2 are respectively located at the two ends of the rear side of the shell W, and the cooling fan F1 and the cooling fan F2 are located in the middle position of the rear side of the shell W, and are located in the middle of the incoming line aviation plug interface P1 and the outgoing line aviation plug interface P2; the radiator S is located at the rear side of the inside of the shell W, the three-way parallel circuit board B2 is located at the upper end of the radiator S, and the input processing circuit board B1 is located at the front right side of the inside of the shell W, that is, the right side of the front end of the radiator S; the control board B4 is located at the front end of the radiator S, on the left side of the input processing circuit board B1; The auxiliary power board B5 is located at the front end of the control board B4 and on the left side of the input processing circuit board B1; the three-way parallel inductors L1~L3 are located on the left front side of the inside of the shell W, the front end of the radiator S, and the left side of the control board B4; the output processing circuit board B3 is located on the left front side of the inside of the shell W, the front end of the three-way parallel inductors L1~L3, and the left side of the auxiliary power board B5; the communication interface T1 is located on the left side of the front end chassis panel of the shell W, the display circuit board B6 is located in the middle part of the front end chassis panel of the shell W, and the air switch K1 is located on the right side of the front end chassis panel of the shell W.

[0005] As a preferred embodiment of the present invention, the input processing circuit board B1 includes but is not limited to: fuse FU1, varistor RV1, varistor RV2, varistor RV3, discharge tube G1, soft-start relay KM1, anti-reverse diode D1, soft-start resistor R1, fuse FU2.

[0006] As a preferred embodiment of the present invention, the three-way parallel circuit board B2 includes but is not limited to: a current Hall sensor H1, a current limiting resistor Rx, a voltage Hall sensor H2, an input filter capacitor C1, a chopper bridge arm 1, a chopper bridge arm 2, and a chopper bridge arm 3.

[0007] As a preferred embodiment of the present invention, the output processing circuit board B3 includes but is not limited to: fuse FU1, fuse FU2, fuse FU3, shunt FL1, shunt FL2, shunt FL3, output filter capacitor C2, soft start relay KM2, fuse FU6, soft start resistor R2, anti-reverse diode D2, varistor RV4, sampling resistors R3 and R4, and grounding capacitors C3 and C4.

[0008] As a preferred embodiment of the present invention, the positive and negative input ends of the auxiliary power board B5 are the positive pole DC+ and the negative pole DC- of the DC bus, and the outputs are +15V port, -15V port, 5V port and AGND port. The auxiliary power board B5 supplies power to the control board B4, the display circuit board B6, the current Hall sensor H1 and the voltage Hall sensor H2.

[0009] As a preferred embodiment of the present invention, the control board B4 includes but is not limited to: power supply, relay KM1 and KM2 control signal input, switch tube S1~S6 drive signal output, hardware fault signal input, control switch quantity input and output, key point temperature sampling signal input, AD sampling signal input, CAN communication and parameter display signal output.

[0010] The invention provides a low-voltage and high-current bidirectional DC / DC power supply that can be connected in parallel, and has the following beneficial effects:

[0011] The switching device of the present invention uses MOSFET power switch tube, the switching frequency can reach 100kHz, and a single module adopts the form of three chopper bridge arms in parallel. The other three bridge arms are staggered in parallel control by shifting the phase by 120°, which can greatly reduce the output current ripple. Therefore, through the high switching frequency and the staggered parallel control between the three bridge arms, the volume of the output filter inductor and capacitor can be greatly reduced, and the power density of the power supply is improved as a whole. The present invention proposes to define the power output terminal DCout+ as the analog ground AGND, so that AGND can be used as the reference ground for output side voltage sampling and current sampling. Therefore, a shunt can be used to sample three currents, and a voltage divider resistor can be used to sample the output voltage. In this way, the output side can avoid sampling using a Hall sensor, which greatly reduces the cost and improves the sampling accuracy. The present invention can realize the parallel connection of multiple modules, and the modules can be coordinated and controlled through communication. The expansion can be realized according to the requirements of different forklift power levels, and the power flow can be realized in two directions. The kinetic energy of the forklift and the potential energy of the workbench can be fed back to the power supply battery, which greatly improves the system efficiency, increases the working time of the forklift, and improves the utilization rate of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Other features, objects and advantages of the present invention will become more apparent from the detailed description of non-limiting embodiments made with reference to the following drawings:

[0013] Figure 1 The present invention is a schematic diagram of a low-voltage and high-current bidirectional DC / DC direct current power supply circuit that can be connected in parallel.

[0014] Figure 2 The present invention is a top view of the overall structure of a low-voltage, high-current, bidirectional DC / DC direct current power supply that can be connected in parallel.

[0015] In the figure: 1. Shell W, 2. Radiator S, 3. Three-way parallel inductors L1~L3, 4. Output processing circuit board B3, 5. Communication interface T1, 6. Display circuit board B6, 7. Air switch K1, 8. Auxiliary power board B5, 9. Input processing circuit board B1, 10. Control board B4, 11. Three-way parallel circuit board B2, 12. Inlet aviation plug interface P1, 13. Cooling fan F1, 14. Cooling fan F2, 15. Outlet aviation plug interface P2. DETAILED DESCRIPTION

[0016] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0017] See also Figure 1-Figure 2The present invention provides a low-voltage and high-current bidirectional DC / DC power supply that can be connected in parallel, including: an air switch K17, an input processing circuit board B19, a three-way parallel circuit board B211, three-way parallel inductors L1-L33, an output processing circuit board B34, a control board B410, an auxiliary power board B58, a display circuit board B66, a chassis shell W1, a radiator S2, a cooling fan F113, a cooling fan F214, an inlet aviation plug interface P112, an outlet aviation plug interface P215, and a communication interface T15, characterized in that: the shell W 1 is provided with a cooling fan F113 and a cooling fan F214 as well as an incoming aviation plug interface P112 and an outgoing aviation plug interface P215 inside the rear side, wherein the incoming aviation plug interface P112 is the high-voltage side input terminal DCin+ and DCin-, the incoming aviation plug interface P112 is connected to the air switch K17, and then connected to the lightning protection circuit of the input processing circuit board B19, the output of the lightning protection circuit is connected to the high-voltage side pre-charging link in the input processing circuit board B19, the output of the high-voltage side pre-charging link of the input processing circuit board B19 is connected to the high-voltage side sampling circuit of the three-way parallel circuit board B211, the high-voltage side sampling circuit is connected to the input filter capacitor C1, the positive and negative ends of the filter capacitor C1 are connected to the three-way parallel chopper circuit, the three-way parallel chopper circuit is then connected to the three-way parallel inductors L1~L33 on the output side, the three-way parallel inductors L1~L33 are connected to the three-way parallel inductors L1~L33 of the output processing circuit board B34 Fuses FU3~FU5, three-way fuses FU3~FU5 are then connected to three-way current detection shunts FL1~FL3, the output sides of the three-way current detection shunts FL1~FL3 are connected together, through the output filter capacitor C2, the positive electrode of the output filter capacitor C2 is connected to the low-voltage side pre-charging link, the low-voltage side pre-charging link passes through the varistor RV4, and then passes through the output side sampling voltage divider resistors R3 and R4 to the output terminals DCout+ and DCout-, the cooling fan F113 and the cooling fan F214 power supply circuit DLfan are respectively connected to the output terminals DCout+ and DCout-, wherein DCout+ is connected to the positive terminal of the cooling fan F113 and the cooling fan F214 after passing through the temperature control switch St in the cooling fan F113 and the cooling fan F214 power supply circuit DLfan, and DCout- is directly connected to the negative terminal of the cooling fan F113 and the cooling fan F214, and the front chassis panel of the shell W1 is provided with a display circuit board B66 and a communication interface T15.

[0018] See also Figure 1 and Figure 2As a preferred embodiment of the present invention, the inlet aviation plug interface P112 and the outlet aviation plug interface P215 are respectively located at the two ends of the rear side of the shell W1, and the cooling fan F113 and the cooling fan F214 are located in the middle of the rear side of the shell W1, and are located between the inlet aviation plug interface P112 and the outlet aviation plug interface P215; the radiator S2 is located at the rear side of the shell W1, the three-way parallel circuit board B211 is located at the upper end of the radiator S2, and the input processing circuit board B19 is located at the front right side of the shell W1, that is, the right side of the front end of the radiator S2; the control board B410 is located at the front end of the radiator S2, on the left side of the input processing circuit board B19; the auxiliary power board B58 is located at the front end of the control board B410, on the left side of the input processing circuit board B19; the three-way parallel inductors L1~L33 are located at the front left side of the shell W1, the front end of the radiator S2, and the left side of the control board B410; the output processing circuit board B34 is located at the shell W 1 is located at the left front side of the interior, at the front end of the three-way parallel inductor L1~L33, and at the left side of the auxiliary power supply board B58; the communication interface T15 is located at the leftmost side of the frontmost chassis panel of the shell W1, the display circuit board B66 is located at the middle part of the frontmost chassis panel of the shell W1, and the air switch K17 is located at the rightmost side of the frontmost chassis panel of the shell W1.

[0019] See also Figure 1 and Figure 2 As a preferred embodiment of the present invention, the input processing circuit board B19 includes but is not limited to: fuse FU1, varistor RV1, varistor RV2, varistor RV3, discharge tube G1, soft-start relay KM1, anti-reverse diode D1, soft-start resistor R1, fuse FU2.

[0020] See also Figure 1 and Figure 2 As a preferred embodiment of the present invention, the three-way parallel circuit board B211 includes but is not limited to: a current Hall sensor H1, a current limiting resistor Rx, a voltage Hall sensor H2, an input filter capacitor C1, a chopper bridge arm 1, a chopper bridge arm 2, and a chopper bridge arm 3.

[0021] See also Figure 1 and Figure 2 As a preferred embodiment of the present invention, the output processing circuit board B34 includes but is not limited to: fuse FU1, fuse FU2, fuse FU3, shunt FL1, shunt FL2, shunt FL3, output filter capacitor C2, soft start relay KM2, fuse FU6, soft start resistor R2, anti-reverse diode D2, varistor RV4, sampling resistors R3 and R4, and grounding capacitors C3 and C4.

[0022] See also Figure 1 and Figure 2 As a preferred embodiment of the present invention, the positive and negative input terminals of the auxiliary power board B58 are the positive pole DC+ and the negative pole DC- of the DC bus, and the outputs are +15V port, -15V port, 5V port and AGND port. The auxiliary power board B58 supplies power to the control board B410, the display circuit board B66, the current Hall sensor H1 and the voltage Hall sensor H2.

[0023] See also Figure 1 and Figure 2 As a preferred embodiment of the present invention, the control board B410 includes but is not limited to: power supply, relay KM1 and KM2 control signal input, switch tube S1~S6 drive signal output, hardware fault signal input, control switch quantity input and output, key point temperature sampling signal input, AD sampling signal input, CAN communication and parameter display signal output.

[0024] A low-voltage and high-current bidirectional DC / DC power supply that can be connected in parallel is connected in the following manner: the input terminals DCin+ and DCin- on the high-voltage side of the power supply are connected to the positive and negative input terminals of a dual-circuit air switch K1, the positive output terminal DCK+ of the dual-circuit air switch K1 is connected to one end of a fuse FU1, the other end of the fuse FU1 is connected to one end of a varistor RV1 and one end of a varistor RV3, and is connected to one end of a soft-start relay KM1 and one end of an anti-reverse diode D1, the other end of the varistor RV1 is connected to one end of a discharge tube G1 and one end of a varistor RV2, the other end of the discharge tube G1 is connected to a chassis shell W, the other end of the varistor RV2 and the other end of the varistor RV3 are connected to the negative output terminal DC of the dual-circuit air switch K1, and the other end of the varistor RV1 is connected to the negative output terminal DC of the dual-circuit air switch K1. K-, the other end of the anti-reverse diode D1 is connected to one end of the soft-start resistor R1, the other end of the soft-start resistor R1 is connected to one end of the fuse FU2, the other end of the fuse FU2 and the other end of the soft-start relay KM1 are simultaneously connected to the input end of the input side current Hall sensor H1, the output end of the current Hall sensor H1 is connected to the DC bus positive pole DC+ and one end of the input side voltage sampling current limiting resistor Rx, the other end of the current limiting resistor Rx is connected to one end of the input side voltage Hall sensor H2, one end of the input side filter capacitor C1 is connected to the DC bus positive pole DC+, the other end of the input side filter capacitor C1 and the other end of the voltage Hall sensor H2 are connected to the DC bus negative pole DC-, and the DC bus negative pole DC- and the negative output end DCK- of the air switch K1 are the same end.In the three-way parallel chopper circuit, port 1 of chopper bridge arm 1, port 1 of chopper bridge arm 2 and port 1 of chopper bridge arm 3 are connected to the positive pole DC+ of the DC bus, port 3 of chopper bridge arm 1, port 3 of chopper bridge arm 2 and port 3 of chopper bridge arm 3 are connected to the negative pole DC- of the DC bus, port 2 of chopper bridge arm 1 is connected to one side of the filter inductor L1 among the three-way parallel filter inductors L1 to L3, port 2 of chopper bridge arm 2 is connected to one side of the filter inductor L2 among the three-way parallel filter inductors L1 to L3, port 2 of chopper bridge arm 3 is connected to one side of the filter inductor L3 among the three-way parallel filter inductors L1 to L3, the other side of the filter inductor L1 among the three-way parallel filter inductors L1 to L3 is connected to one side of the fuse FU3, the other side of the filter inductor L2 among the three-way parallel filter inductors L1 to L3 is connected to one side of the fuse FU4, and the three-way parallel filter inductors L1 to L3 are connected to the positive pole DC+ of the DC bus, port 3 of chopper bridge arm 1 is connected to one side of the filter inductor L1 among the three-way parallel filter inductors L1 to L3, The other side of the filter inductor L3 in the wave inductor L1~L3 is connected to one side of the fuse FU5, the other side of the fuse FU3 is connected to the positive pole + of the shunt FL1 in the three-way current detection shunts FL1~FL3, the other side of the fuse FU4 is connected to the positive pole + of the shunt FL2 in the three-way current detection shunts FL1~FL3, the other side of the fuse FU5 is connected to the positive pole + of the shunt FL3 in the three-way current detection shunts FL1~FL3, the negative pole - of the shunt FL1 in the three-way current detection shunts FL1~FL3, the negative pole - of the shunt FL2 in the three-way current detection shunts FL1~FL3 and the negative pole - of the shunt FL3 in the three-way current detection shunts FL1~FL3 are connected together to one end of the output filter capacitor C2, and at the same time connected to one end of the soft-start relay KM2 and one end of the fuse FU6. The other end of the fuse FU6 is connected to one end of the soft-start resistor R2, the other end of the soft-start resistor R2 is connected to one end of the anti-reverse diode D2, and the other end of the anti-reverse diode D2 and the other end of the soft-start relay KM2 are simultaneously connected to the output positive electrode DCout+. The other end of the output filter capacitor C2 is connected to the output negative electrode DCout-, and DCout- is the same end as the DC bus negative electrode DC- and the negative output terminal DCK- of the air switch K1. One end of the varistor RV4 is connected to the output positive electrode DCout+, and the other end of the varistor RV4 is connected to the output negative electrode DCout-. The voltage sampling resistors R3 and R4 are connected in series and in parallel with the output filter capacitor C2. In the cooling fan power supply circuit DLfan, one end of the temperature control switch St is connected to the output positive electrode DCout+, and the other end of the temperature control switch St is connected to the input positive electrode Vin+ of the cooling fan, and the input negative electrode Vin- of the cooling fan is connected to the power supply output negative electrode DCout-. One side of the grounding capacitor C3 is connected to the power supply output positive electrode DCout+, and one side of the grounding capacitor C4 is connected to the power supply output negative electrode DCout-. The other side of the grounding capacitor C3 and the other side of the grounding capacitor C4 are simultaneously connected to the chassis housing W. At the same time, the positive electrode DCout+ of the power output is defined as the analog reference ground AGND.

[0025] The switching device of the present invention uses MOSFET power switch tube, the switching frequency can reach 100kHz, and a single module adopts the form of three chopper bridge arms in parallel. The other three bridge arms are staggered in parallel control by shifting the phase by 120°, which can greatly reduce the output current ripple. Therefore, through the high switching frequency and the staggered parallel control between the three bridge arms, the volume of the output filter inductor and capacitor can be greatly reduced, and the power density of the power supply is improved as a whole. The present invention proposes to define the power output terminal DCout+ as the analog ground AGND, so that AGND can be used as the reference ground for output side voltage sampling and current sampling. Therefore, a shunt can be used to sample three currents, and a voltage divider resistor can be used to sample the output voltage. In this way, the output side can avoid sampling using a Hall sensor, which greatly reduces the cost and improves the sampling accuracy. The present invention can realize the parallel connection of multiple modules, and the modules can be coordinated and controlled through communication. The expansion can be realized according to the requirements of different forklift power levels, and the power flow can be realized in two directions. The kinetic energy of the forklift and the potential energy of the workbench can be fed back to the power supply battery, which greatly improves the system efficiency, increases the working time of the forklift, and improves the utilization rate of the battery.

[0026] The above shows and describes the basic principles and main features of the present invention and the advantages of the present invention. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, no matter from which point of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the attached claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims are included in the present invention. Any figure mark in the claims should not be regarded as limiting the claims involved.

[0027] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A low-voltage, high-current, bidirectional DC / DC power supply that can be connected in parallel, comprising: Air switch K1 (7), input processing circuit board B1 (9), three-way parallel circuit board B2 (11), three-way parallel inductors L1~L3 (3), output processing circuit board B3 (4), control board B4 (10), auxiliary power board B5 (8), display circuit board B6 (6), chassis shell W (1), radiator S (2), cooling fan F1 (13), cooling fan F2 (14), incoming line aviation plug interface P1 (12), outgoing line aviation plug interface P2 (15), communication interface T1 (5), characterized in that: the rear side of the shell W (1) is provided with cooling fan F1 (13) and cooling fan F2 (14) to and an incoming line aviation plug interface P1 (12) and an outgoing line aviation plug interface P2 (15), wherein the incoming line aviation plug interface P1 (12) is the high-voltage side input terminal DCin+ and DCin-, the incoming line aviation plug interface P1 (12) is connected to the air switch K1 (7), and then connected to the lightning protection circuit of the input processing circuit board B1 (9), the output of the lightning protection circuit is connected to the high-voltage side pre-charging link in the input processing circuit board B1 (9), the output of the high-voltage side pre-charging link of the input processing circuit board B1 (9) is connected to the high-voltage side sampling circuit of the three-way parallel circuit board B2 (11), and the high-voltage side sampling circuit is connected to the input filter capacitor C1, The positive and negative ends of the filter capacitor C1 are connected to a three-way parallel chopper circuit, and the three-way parallel chopper circuit is connected to the three-way parallel inductor L1~L3(3) on the output side. The three-way parallel inductor L1~L3(3) is connected to the three-way fuse FU3~FU5 of the output processing circuit board B3(4), and the three-way fuse is connected to the three-way current detection shunt FL1~FL3. The output sides of the three-way current detection shunt FL1~FL3 are connected together, through the output filter capacitor C2, and the positive electrode of the output filter capacitor C2 is connected to the low-voltage side pre-charging link. The low-voltage side pre-charging link passes through the varistor RV4, and then passes through the output side sampling voltage divider resistors R3 and R4 to the output The output terminals DCout+ and DCout- are connected to the power supply circuits DLfan of the cooling fan F1 (13) and the cooling fan F2 (14) respectively, wherein DCout+ is connected to the positive terminals of the cooling fan F1 (13) and the cooling fan F2 (14) through the temperature control switch St in the power supply circuits DLfan of the cooling fan F1 (13) and the cooling fan F2 (14), and DCout- is directly connected to the negative terminals of the cooling fan F1 (13) and the cooling fan F2 (14). The front panel of the housing W (1) is provided with a display circuit board B6 (6) and a communication interface T1 (5); The inlet aviation plug interface P1 (12) and the outlet aviation plug interface P2 (15) are respectively located at the two ends of the rear side of the housing W (1); the cooling fan F1 (13) and the cooling fan F2 (14) are located in the middle of the rear side of the housing W (1), and are located between the inlet aviation plug interface P1 (12) and the outlet aviation plug interface P2 (15); the radiator S (2) is located at the rear side of the housing W (1); the three-way parallel circuit board B2 (11) is located at the upper end of the radiator S (2); the input processing circuit board B1 (9) is located at the front right side of the housing W (1), that is, at the right side of the front end of the radiator S (2); the control board B4 (10) is located at the front end of the radiator S (2), and the left side of the input processing circuit board B1 (9) is located at the right side of the front end of the radiator S (2); side; the auxiliary power board B5 (8) is located at the front end of the control board B4 (10), on the left side of the input processing circuit board B1 (9); the three-way parallel inductance L1~L3 (3) is located on the left front side of the shell W (1), the front end of the heat sink S, and the left side of the control board B4; the output processing circuit board B3 (4) is located on the left front side of the shell W (1), the front end of the three-way parallel inductance L1~L3 (3), and the left side of the auxiliary power board B5 (8); the communication interface T1 (5) is located on the left side of the front end chassis panel of the shell W (1), the display circuit board B6 is located in the middle part of the front end chassis panel of the shell W (1), and the air switch K1 (7) is located on the right side of the front end chassis panel of the shell W (1); The input processing circuit board B1 (9) includes: a fuse FU1, a varistor RV1, a varistor RV2, a varistor RV3, a discharge tube G1, a soft-start relay KM1, an anti-reverse diode D1, a soft-start resistor R1, and a fuse FU2; The three-way parallel circuit board B2 (11) comprises: a current Hall sensor H1, a current limiting resistor Rx, a voltage Hall sensor H2, an input filter capacitor C1, a chopper bridge arm 1, a chopper bridge arm 2, and a chopper bridge arm 3; The output processing circuit board B3 (4) includes: fuse FU1, fuse FU2, fuse FU3, shunt FL1, shunt FL2, shunt FL3, output filter capacitor C2, soft start relay KM2, fuse FU6, soft start resistor R2, anti-reverse diode D2, varistor RV4, sampling resistors R3 and R4, and grounding capacitors C3 and C4.

2. The low-voltage, high-current, bidirectional DC / DC power supply that can be connected in parallel according to claim 1, characterized in that: The positive and negative input terminals of the auxiliary power board B5 (8) are the positive pole DC+ and the negative pole DC- of the DC bus, and the output terminals are a +15V port, a -15V port, a 5V port and an AGND port. The auxiliary power board B5 (8) supplies power to the control board B4 (10), the display circuit board B6 (6), the current Hall sensor H1 and the voltage Hall sensor H2.

3. The low-voltage, high-current, bidirectional DC / DC power supply that can be connected in parallel according to claim 1, characterized in that: The control board B4 (10) includes: power supply, relay KM1 and KM2 control signal input, switch tube S1~S6 drive signal output, hardware fault signal input, control switch input and output, key point temperature sampling signal input, AD sampling signal input, CAN communication and parameter display signal output.

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