A charging system

Abstract

This application provides a charging system for the energy technology field, enabling more reliable removal of a short-circuited AC-DC converter circuit when multiple AC-DC converter circuits are connected in parallel to a DC bus. The charging system includes at least two AC-DC converter circuits, at least two first fuse groups, at least one DC-DC converter circuit, and an auxiliary fuse module. The input terminal of each AC-DC converter circuit is connected to an AC power source, and the output terminal of each AC-DC converter circuit is connected to the positive and negative DC bus via corresponding first fuse groups. The input terminal of each DC-DC converter circuit is also connected to the positive and negative DC bus. The auxiliary fuse module is connected to the positive and negative DC bus, and outputs an auxiliary fuse current in the event of a short circuit at the output terminal of the AC-DC converter circuit, thereby removing the AC-DC converter circuit from the charging system.

Description

Technical Field

[0001] This application relates to the field of energy technology, and in particular to a charging system. Background Technology

[0002] With the continuous development of new energy vehicles, the distribution of charging stations is becoming increasingly widespread. In charging stations with a split structure, multiple alternating current-to-direct current (AC-DC) converters and multiple direct current-to-direct current (DC-DC) converters are typically connected in parallel to the DC bus. However, in these parallel AC-DC converters, if one converter fails and causes a short circuit at its output, the other parallel AC-DC converters will also experience short circuits at their outputs, affecting the normal operation of the charging station. To prevent a short circuit in one AC-DC converter from affecting the others, fuses can be installed at the output of each AC-DC converter to disconnect the faulty converter from the DC bus. However, in medium and low power applications, when the number of parallel AC-DC converters is small, a short-circuited AC-DC converter may not be able to be disconnected. Therefore, a solution to address this problem is urgently needed. Summary of the Invention

[0003] This application provides a charging system that more reliably removes short-circuited AC-DC converters at their output terminals when multiple AC-DC converters are connected in parallel to a DC bus.

[0004] To achieve the above objectives, the embodiments of this application provide the following technical solutions:

[0005] In a first aspect, a charging system is provided, comprising at least two AC-DC converter circuits, at least two first fuse groups, at least one DC-DC converter circuit, and an auxiliary fuse module. Each first fuse group includes two fuses. The input terminal of each AC-DC converter circuit is connected to an AC power source. The positive output terminal of each AC-DC converter circuit is connected to a positive DC bus via a fuse from one of the corresponding first fuse groups, and the negative output terminal of each AC-DC converter circuit is connected to a negative DC bus via the other fuse from one of the corresponding first fuse groups. The positive input terminal of the DC-DC converter circuit is connected to the positive DC bus, and the negative input terminal of the DC-DC converter circuit is connected to the negative DC bus. The positive terminal of the auxiliary fuse module is connected to the positive DC bus, and the negative terminal of the auxiliary fuse module is connected to the negative DC bus. The auxiliary fuse module is used to output an auxiliary fusing current in the event of a short circuit at the output terminal of the AC-DC converter circuit, the auxiliary fusing current being greater than or equal to the short-circuit current at the output terminal of the AC-DC converter circuit.

[0006] When one AC-DC converter is functioning normally and the output terminals of other AC-DC converters are short-circuited, the normal AC-DC converter, the positive DC bus, the negative DC bus, and the two fuses of the short-circuited AC-DC converter form a closed loop. However, when there are two AC-DC converters, the output current of the normal AC-DC converter is much smaller than the fuse's breaking current, causing the fuse to fail to blow and affecting the operation of the normal AC-DC converter. In this case, the auxiliary fuse module outputs an auxiliary fusing current that makes the current flowing through the fuse greater than the fuse's breaking current, thus more reliably removing the short-circuited AC-DC converter from the output terminal. Furthermore, when there are more than two AC-DC converters, the auxiliary fusing current output by the auxiliary fuse module can also remove the short-circuited AC-DC converter from the charging system more quickly.

[0007] In one embodiment, the auxiliary fuse module includes a first capacitor, a second capacitor, a first voltage equalizing resistor, and a second voltage equalizing resistor. The first capacitor and the second capacitor are connected in series between the positive terminal and the negative terminal of the auxiliary fuse module. The first voltage equalizing resistor is connected in parallel with the first capacitor, and the second voltage equalizing resistor is connected in parallel with the second capacitor.

[0008] Using the above method, two low-voltage capacitors can be connected in series for energy storage, and the voltages across the first and second capacitors can be dynamically balanced through a first and a second voltage-equalizing resistor. Based on this, when the output of the AC-DC converter circuit is short-circuited, the auxiliary fuse module can both output an auxiliary fuse current and prevent damage to the capacitors.

[0009] In one embodiment, the auxiliary fuse module includes a supercapacitor, one end of which is connected to the positive terminal of the auxiliary fuse module, and the other end of which is connected to the negative terminal of the auxiliary fuse module. Using a supercapacitor for energy storage in the energy storage circuit can reduce the need for voltage equalization resistors.

[0010] In one embodiment, the auxiliary fuse module further includes a second fuse group, which comprises two fuses. The positive terminal of the auxiliary fuse module is connected to the positive DC bus via one fuse in the second fuse group, and the negative terminal of the auxiliary fuse module is connected to the negative DC bus via the other fuse in the second fuse group.

[0011] With the second fuse group, when there is a short circuit fault at the positive and negative terminals of the auxiliary fuse module, the output current of the normal AC-DC conversion circuit can also blow the two fuses in the second fuse group, thereby removing the auxiliary fuse module.

[0012] In one embodiment, the second fuse group and the first fuse group are fuse groups of the same specifications. Based on this, it can be ensured that the fuses can blow more reliably when the positive and negative terminals of the auxiliary fuse module are short-circuited or the output terminal of the AC-DC conversion circuit is short-circuited.

[0013] In one embodiment, the charging system further includes a bidirectional DC-DC converter circuit and an energy storage battery, the energy storage battery being connected to the positive DC bus and the negative DC bus via the bidirectional DC-DC converter circuit.

[0014] In this way, when the charging system of the charging station includes a bidirectional DC-DC converter circuit and a DC stack composed of energy storage batteries, the AC-DC converter circuit with a short circuit at the output terminal can also be removed.

[0015] In one embodiment, the charging system further includes a third fuse group comprising two fuses. A bidirectional DC-DC converter circuit is connected to the positive DC bus through one fuse in the third fuse group, and a bidirectional DC-DC converter circuit is connected to the negative DC bus through the other fuse in the third fuse group.

[0016] In this way, when a short circuit fault occurs at one end of the bidirectional DC-DC converter circuit connected to the DC bus, the auxiliary fuse current output by the auxiliary fuse module can ensure more reliable fusing of the third fuse group.

[0017] In one embodiment, the charging system further includes at least one fourth fuse group, which is connected to the at least one DC-DC converter circuit in a one-to-one correspondence. Each fourth fuse group includes two fuses. The positive input terminal of each DC-DC converter circuit is connected to the positive DC bus through one fuse in the corresponding fourth fuse group, and the negative input terminal of each DC-DC converter circuit is connected to the negative DC bus through the other fuse in the corresponding fourth fuse group.

[0018] In this way, when the input terminal of the DC-DC converter circuit is short-circuited, the auxiliary fuse current output by the auxiliary fuse module can also ensure more reliable fusing of the fourth fuse group.

[0019] In one embodiment, the fusing Joule integral value of the fuse in the fourth fuse group is less than the arc-precession Joule integral value of the fuse in the first fuse group.

[0020] By selecting fuses with a Joule integral value less than the arc-precursor Joule integral value of the fuses in the first fuse group to form the fourth fuse group of the DC-DC converter module, when a DC-DC converter circuit fails, only the fuse group corresponding to that DC-DC converter circuit will blow, without affecting the fuses corresponding to the AC-DC converter circuit, thereby ensuring the stability of parallel protection for the AC-DC converter circuit.

[0021] In one implementation, when the number of AC-DC converter circuits is greater than or equal to three, the pre-arc Joule integral value of the fuse in the first fuse group is greater than one-quarter of the fusing Joule integral value of the fuse in the first fuse group.

[0022] By selecting fuses with a pre-arc Joule integral value greater than one-quarter of the fusing Joule integral value to form the first fuse group of the AC-DC converter circuit, when an AC-DC converter circuit fails, only the fuse group corresponding to that AC-DC converter circuit will blow, without affecting the normal operation of the fuse groups corresponding to other AC-DC converter circuits, thereby ensuring the stability of parallel protection for AC-DC converter circuits. Attached Figure Description

[0023] Figure 1 A schematic diagram of a charging system provided in an embodiment of this application;

[0024] Figure 2 This is another schematic diagram of the charging system provided in the embodiments of this application;

[0025] Figure 3 This is another schematic diagram of the charging system provided in the embodiments of this application;

[0026] Figure 4 This is another schematic diagram of the charging system provided in an embodiment of this application. Detailed Implementation

[0027] It should be noted that the terms "in one embodiment" or "exemplary" in this application are used to indicate examples, illustrations, or descriptions. Any embodiment or design described as "in one embodiment" or "exemplary" in this application should not be construed as being more preferred or advantageous than other embodiments or designs. Specifically, the use of terms such as "in one embodiment" or "exemplary" is intended to present the relevant concepts in a specific manner.

[0028] The technical solutions in this application will now be described with reference to the accompanying drawings.

[0029] With the development of the electric vehicle industry, charging stations are becoming increasingly widespread. The fast charging speed of electric vehicles, low operating costs of charging piles within charging stations, and a good charging experience are the trends in the charging industry. To improve the power utilization rate of charging systems, some AC-DC conversion circuits are often connected in parallel and pooled on the bus. However, protecting multiple unisolated AC-DC conversion circuits connected in parallel presents the following problems: when multiple AC-DC conversion circuits are connected in parallel, if one of them fails, causing a short circuit at the output, the other parallel AC-DC conversion circuits will also experience short circuits at the output, easily leading to fault propagation.

[0030] Therefore, when multiple parallel, non-isolated AC-DC conversion circuits exist in a charging system, short-circuit protection is required for each AC-DC conversion circuit to prevent a failure in any one AC-DC conversion circuit from affecting the normal operation of the others. Furthermore, power conversion systems (PCS) in the photovoltaic industry also have AC-to-DC and DC-to-AC conversion functions. When a power conversion system includes multiple parallel, non-isolated AC-DC conversion circuits, it faces the same challenge.

[0031] To address the aforementioned issues, a common approach is to place switching transistors between each AC-DC converter circuit and the positive and negative DC buses. These switching transistors are typically semiconductor switching devices such as insulated-gate bipolar transistors (IGBTs) or metal-oxide-semiconductor field-effect transistors (MOSFETs).

[0032] Specifically, when any AC-DC converter circuit in the charging system experiences an output short circuit or a grounding protection (PE) short circuit, the current flowing through the switching transistor is large, or when the switching transistor is connected, the voltage across the switching transistor exceeds a set threshold, which will trigger the protection and disconnect the switching transistor. This will remove the AC-DC converter circuit with the short-circuited output from the charging system, thus preventing damage to other AC-DC converter circuits.

[0033] However, the IGBTs and other switching transistors used in the above methods are expensive, which is detrimental to cost control of the charging system. Furthermore, due to the high impedance of IGBTs or MOSFETs, they cause significant power loss during actual use, reducing charging efficiency. Therefore, they are not suitable for the charging pile industry, which has high requirements for charging efficiency.

[0034] Figure 1 This is a schematic diagram of a charging system provided in an embodiment of this application. In some related technologies, such as... Figure 1 As shown, the charging system 100 includes m alternating current-to-direct current (AC-DC) conversion circuits 110 (e.g., ...). Figure 1 The AC-DC converter circuit 1 to AC-DC converter circuit m) and n DC-DC converter circuits 120 (e.g. Figure 1 The DC-DC converter circuits 1 to 110 are listed in the diagram. m is an integer greater than or equal to 3, and n is an integer greater than or equal to 1. The input terminal of each AC-DC converter circuit 110 is connected via a three-phase connection terminal (e.g., ...). Figure 1 The U, V, and W terminals of each AC-DC converter 110 are connected to an AC power source. The positive and negative output terminals of each AC-DC converter 110 are connected to the positive and negative DC buses respectively via a fuse group. The positive input terminal of each DC-DC converter 120 is connected to the positive DC bus BUS+, and the negative input terminal is connected to the negative DC bus BUS-. The positive output terminal Vout+ and the negative output terminal Vout- of each DC-DC converter 120 are used to connect electrical equipment.

[0035] Still Figure 1As shown, the positive output terminal of AC-DC converter circuit 1 is connected to the positive DC bus BUS+ through fuse F11, and the negative output terminal of AC-DC converter circuit 1 is connected to the negative DC bus BUS- through fuse F12. The positive output terminal of AC-DC converter circuit 2 is connected to the positive DC bus BUS+ through fuse F21, and the negative output terminal of AC-DC converter circuit 2 is connected to the negative DC bus BUS- through fuse F22. Similarly, the positive output terminal of AC-DC converter circuit M is connected to the positive DC bus BUS+ through fuse Fm1, and the negative output terminal of AC-DC converter circuit M is connected to the negative DC bus BUS- through fuse Fm2. Fuse F11 and F12 form one fuse group, fuses F21 and F22 form another fuse group, and so on, with fuses Fm1 and Fm2 forming yet another fuse group.

[0036] When the output of the AC-DC converter circuit is short-circuited, the currents flowing through fuses F11, F21, ..., Fm1 are I1, I2, ..., I... m1 When the output terminal of AC-DC converter circuit 1 is short-circuited, the output current of AC-DC converter circuit 2 flows from the positive terminal through fuse F21, positive DC bus BUS+, fuse F11, fuse F12, and fuse F22 back to the negative terminal of AC-DC converter circuit 2. The output current of AC-DC converter circuit m flows from the positive terminal through fuse Fm1, positive DC bus BUS+, fuse F11, fuse F12, and fuse Fm2 back to the negative terminal of AC-DC converter circuit m, making the total current flowing through fuses F11 and F12 I. n =I² + ... + I m1 In this circuit, the short-circuit current of each AC-DC converter is approximately equal, denoted as I0. Therefore, the total current flowing through fuses F11 and F12 is (m-1)I0, and the current flowing through fuses F21 and Fm1 is I0. When the Joule integral of fuses F11 and F12 exceeds the Joule integral of the fuse, the fuse blows. Specifically, when the output of AC-DC converter circuit 1 is short-circuited, (m-1)I0... 2 I0 2 If t > the Joule integral value of fuse F11 and fuse F12, fuse F11 and fuse F12 will blow. AC-DC converter module 1 will be removed from the charging system, and other fuses will continue to operate normally. The Joule integral value represents the total Joule integral of the fuse before it completely blows.

[0037] In this way, when the output terminal of an AC-DC converter 110 is short-circuited, the corresponding AC-DC converter 110 can be removed in time. However, the above solution requires at least three AC-DC converters 110. In medium and low power scenarios, this configuration will limit the power coverage of the charging host, thus limiting the applicability of the product.

[0038] In one embodiment, the positive and negative input terminals of each DC-DC converter circuit 120 are connected to the positive DC bus BUS+ and the negative DC bus BUS- through another fuse group, and each fuse group includes two fuses. Based on this, when the input terminal of a DC-DC converter circuit 120 is short-circuited, the corresponding DC-DC converter circuit 120 can be removed in a timely manner.

[0039] Figure 2 This is another schematic diagram of the charging system provided in an embodiment of this application. In some related technologies, in scenarios where the charging power demand is relatively low, the charging system 100 may include two AC-DC conversion circuits 110 (such as...). Figure 2 AC-DC converter circuit 1 and AC-DC converter circuit 2) and n DC-DC converter circuits 120 (e.g. Figure 2 The DC-DC converter circuits 1 to 2 (DC-DC converter circuit n) are shown in the diagram. The input terminal of AC-DC converter circuit 1 is connected via a three-phase terminal block (e.g., ...). Figure 2 The U, V, and W terminals of the AC-DC converter circuit are connected to the AC power supply. The positive output terminal of AC-DC converter circuit 1 is connected to the positive DC bus BUS+ through electronic fuse efuse1, and the negative output terminal of AC-DC converter circuit 1 is connected to the negative DC bus BUS- through electronic fuse efuse2. The positive output terminal of AC-DC converter circuit 2 is connected to the positive DC bus BUS+ through electronic fuse efuse3, and the negative output terminal of AC-DC converter circuit 2 is connected to the negative DC bus BUS- through electronic fuse efuse4. DC-DC converter circuits 1 to n are connected in parallel to the negative DC bus BUS- and the positive DC bus BUS+.

[0040] An electronic fuse can be installed to promptly remove an AC-DC converter 110 when its output is short-circuited. However, electronic fuses are typically implemented using integrated circuits, which are expensive and generate significant heat, severely impacting the efficiency of the charging host.

[0041] To better address the aforementioned problems, this application provides a charging system 100, which includes at least two AC-DC converter circuits 110, at least two first fuse groups, at least one DC-DC converter circuit 120, and an auxiliary fuse module 130. Each first fuse group includes two fuses. The input terminal of each AC-DC converter circuit 110 is connected to an AC power source via three-phase terminals (U, V, and W). The positive output terminal of each AC-DC converter circuit 110 is connected to the positive DC bus BUS+ via one fuse from its corresponding first fuse group, and the negative output terminal of each AC-DC converter circuit 110 is connected to the negative DC bus BUS- via the other fuse from its corresponding first fuse group. The positive input terminal of each DC-DC converter circuit 120 is connected to the positive DC bus BUS+, and the negative input terminal of each DC-DC converter circuit 120 is connected to the negative DC bus BUS-. The positive terminal of the auxiliary fuse module 130 is connected to the positive DC bus BUS+, and the negative terminal of the auxiliary fuse module 130 is connected to the negative DC bus BUS-. The auxiliary fuse module 130 is used to output an auxiliary fuse current in the event of a short circuit at the output terminal of at least one AC-DC converter circuit 110, and the auxiliary fuse current is greater than or equal to the short-circuit current at the output terminal of the AC-DC converter circuit 110.

[0042] In this way, the output terminals of multiple AC-DC converter circuits 110 are connected in parallel to the positive DC bus BUS+ and the negative DC bus BUS-, thereby realizing bus pooling.

[0043] The specific topology of the AC-DC converter circuit 110 in this embodiment is not limited, as long as it can realize the conversion function between AC and DC and the boost function of increasing the input voltage, for example, the Vienna topology.

[0044] Furthermore, the number of AC-DC converter circuits 110 and DC-DC converter circuits 120 included in the charging system 100 of this application embodiment is not specifically limited. The number of AC-DC converter circuits 110 can be greater than or less than the number of DC-DC converter circuits 120; that is, one AC-DC converter circuit 110 can correspond to one or more DC-DC converter circuits 120, or one DC-DC converter circuit 120 can correspond to one or more AC-DC converter circuits 110. This application embodiment does not limit this. The following description uses a scenario where the charging system 100 includes two AC-DC converter circuits 110 and two DC-DC converter circuits 120 as an example.

[0045] Figure 3This is another schematic diagram of the charging system provided in an embodiment of this application. In one embodiment, as shown... Figure 3 As shown, the charging system 100 includes an AC-DC converter circuit 1, an AC-DC converter circuit 2, a DC-DC converter circuit 1, a DC-DC converter circuit 2, and an auxiliary fuse module 130. The positive output terminal of the AC-DC converter circuit 1 is connected to the positive DC bus BUS+ through fuse F11, and the negative output terminal of the AC-DC converter circuit 1 is connected to the negative DC bus BUS- through fuse F12. Fuses F11 and F12 are the first fuse group corresponding to the AC-DC converter circuit 1.

[0046] The positive output terminal of AC-DC converter circuit 2 is connected to the positive DC bus BUS+ through fuse F21, and the negative output terminal of AC-DC converter circuit 2 is connected to the negative DC bus BUS- through fuse F22. Fuses F21 and F22 constitute the first fuse group corresponding to AC-DC converter circuit 2.

[0047] The positive input terminal of DC-DC converter circuit 1 is connected to the positive DC bus BUS+, and the negative input terminal is connected to the negative DC bus BUS-. The positive output terminal Vout+ and the negative output terminal Vout- of DC-DC converter circuit 1 are used to connect electrical equipment. The positive input terminal of DC-DC converter circuit 2 is connected to the positive DC bus BUS+, and the negative input terminal is connected to the negative DC bus BUS-. The positive output terminal Vout+ and the negative output terminal Vout- of DC-DC converter circuit 2 are used to connect electrical equipment.

[0048] The positive terminal of the auxiliary fuse module 130 is connected to the positive DC bus BUS+, and the negative terminal is connected to the negative DC bus BUS-. The auxiliary fuse module 130 is used to output an auxiliary fuse current in the event of a short circuit at the output of either AC-DC converter circuit 1 or AC-DC converter circuit 2. This auxiliary fuse current is greater than or equal to the short-circuit current at the output of AC-DC converter circuit 1 and AC-DC converter circuit 2.

[0049] In one embodiment, when the output terminal of AC-DC converter circuit 1 is short-circuited, the output current I2 of AC-DC converter circuit 2 is output from the positive terminal of AC-DC converter circuit 2 and flows sequentially through fuse F21, positive DC bus BUS+, fuse F11, fuse F12, negative DC bus BUS- and fuse F22 before returning to the negative terminal of AC-DC converter circuit 2. The auxiliary fusing current I3 output by auxiliary fusing module 130 is output from the positive terminal and flows sequentially through positive DC bus BUS+, fuse F11, fuse F12, negative DC bus BUS- before returning to the negative terminal of auxiliary fusing module 130, so that the total current flowing through fuse F11 and fuse F12 is I2+I3.

[0050] In this circuit, AC-DC converter 1 and AC-DC converter 2 are typically of the same specifications. Therefore, when other modules cause a short circuit at the output of the AC-DC converter circuit due to a fault, the short-circuit current at the output of AC-DC converter 1 is I1. The current I1 is approximately the same as the short-circuit current I2 at the output of AC-DC converter 2, and is set as I0. Without the auxiliary fuse module 130, the fusing current of fuses F11 and F12 is I0. When the auxiliary fuse module 130 is present, if the auxiliary fusing current I3 is greater than or equal to the short-circuit current (i.e., current I0) at the output of AC-DC converter 1, the total current I2+I3 flowing through fuses F11 and F12 is greater than or equal to the fusing current, thus satisfying the fusing condition and allowing fuses F11 and F12 to fuse.

[0051] In one embodiment, when the auxiliary fuse current I3 is equal to the short-circuit current at the output of AC-DC converter 1, and a short circuit occurs at the output of AC-DC converter 1, the current through fuses F11 and F12 is I2 + I3 = 2I0, which is the fuse Joule integral value W. B =4I0 2 At this time, the Joule integral value W3 = I0 of fuses F21 and F31 is... 2 When the Joule integral value before the arc of the fuse is greater than one-quarter of the Joule integral value before melting, fuses F11 and F12 meet the melting condition, while fuses F21 and F31 are unaffected. The Joule integral value before the arc represents the Joule integral value of the fuse before the molten material melts.

[0052] Therefore, in order to ensure the normal operation of fuses F21 and F31, W3 should be less than the arc-front Joule integral value W of the fuse. A The Joule integral before the arc W AIt is the Joule integral of the short-circuit current absorbed by the fuse before arcing. The time from when the fuse begins to melt until it is completely melted is the arcing time. During the arcing time, the current in the short-circuit circuit gradually decreases to zero. The sum of the pre-arc time and the arcing time is the complete breaking time of the entire circuit, that is, the time from the start of the short circuit to when the fuse is completely melted.

[0053] Furthermore, since the fuses in the same fuse group have the same specifications, the arc-front Joule integral value W of fuse F11 and fuse F12 is... A It should be greater than the Joule integral value W of fuse F11. B One-quarter of it.

[0054] Furthermore, this application does not limit the material or size of the fuse, as long as it can achieve melting when the current exceeds the set threshold according to the Joule integral relationship.

[0055] In one embodiment, it remains as follows Figure 3 As shown, the auxiliary fuse module 130 includes a first capacitor C1, a second capacitor C2, a first voltage equalizing resistor R1, and a second voltage equalizing resistor R2. The first capacitor C1 and the second capacitor C2 are connected in series between the positive and negative terminals of the auxiliary fuse module 130. The first voltage equalizing resistor R1 is connected in parallel with the first capacitor C1, and the second voltage equalizing resistor R2 is connected in parallel with the second capacitor C2.

[0056] When both AC-DC converter circuit 1 and AC-DC converter circuit 2 are functioning normally, energy can be stored using the power from the DC bus through the first capacitor C1 and the second capacitor C2. The first voltage equalizing resistor R1 and the second voltage equalizing resistor R2 can adjust the voltage across the first capacitor C1 and the second capacitor C2, achieving dynamic voltage balance and preventing damage to the first capacitor C1 and the second capacitor C2 due to bias.

[0057] In one embodiment, the auxiliary fuse module 130 further includes a second fuse group, which comprises two fuses, namely fuse F31 and fuse F32. The positive terminal of the auxiliary fuse module 130 is connected to the positive DC bus BUS+ through fuse F31, and the negative terminal of the auxiliary fuse module 130 is connected to the negative DC bus BUS- through fuse F32. Fuses F31, F32, F11, and F12 are all of the same specification.

[0058] In this way, when the positive and negative terminals of the auxiliary fuse module 130 are short-circuited, the output current of both the AC-DC converter circuit 1 and the AC-DC converter circuit 2 will flow through fuses F31 and F32, so that fuses F31 and F32 can be reliably blown.

[0059] In one embodiment, the charging system 100 further includes a bidirectional DC-DC converter circuit 140 and an energy storage battery 150. The positive terminal of one end of the bidirectional DC-DC converter circuit 140 is connected to the positive DC bus BUS+, and the negative terminal of one end of the bidirectional DC-DC converter circuit 140 is connected to the negative DC bus BUS-. The positive terminal of the other end of the bidirectional DC-DC converter circuit 140 is connected to the positive terminal of the energy storage battery 150, and the negative terminal of the other end of the bidirectional DC-DC converter circuit 140 is connected to the negative terminal of the energy storage battery 150.

[0060] In one embodiment, the charging system 100 may further include a third fuse group. The third fuse group includes two fuses. The bidirectional DC-DC converter circuit 140 connects the positive DC bus BUS+ and the negative DC bus BUS- through the two fuses in the third fuse group. Still as Figure 3 As shown, the positive terminal of one end of the bidirectional DC-DC converter circuit 140 is connected to the positive DC bus BUS+ through fuse F41, and the negative terminal of the other end of the bidirectional DC-DC converter circuit 140 is connected to the negative DC bus BUS- through fuse F42.

[0061] When the input terminal of the bidirectional DC-DC converter circuit 140 is short-circuited, the output current I3 of the auxiliary fuse module 130, the output current I1 of the AC-DC converter circuit 1, and the output current I2 of the AC-DC converter circuit 2 will all flow through fuses F41 and F42, making the total current flowing through fuses F41 and F42 greater than the fusing current of fuses F41 and F42. This ensures that fuses F41 and F42 can reliably blow, thereby removing the faulty bidirectional DC-DC converter circuit 140 and energy storage battery 150 from the charging system 100.

[0062] In the above implementation process, the bidirectional DC-DC converter circuit 140 can be used as part of the charging system or as a load. When the charging system 100 is idle, the bidirectional DC-DC converter circuit 140 charges the corresponding energy storage battery 150 through the AC-DC converter circuit 110.

[0063] In one embodiment, the charging system 100 further includes at least one fourth fuse group. The at least one fourth fuse group is connected in a one-to-one correspondence with the at least one DC-DC converter circuit. Each fourth fuse group includes two fuses. The positive input terminal of each DC-DC converter circuit 120 is connected to the positive DC bus BUS+ through one fuse in the corresponding fourth fuse group, and the negative input terminal of each DC-DC converter circuit 120 is connected to the negative DC bus BUS- through the other fuse in the corresponding fourth fuse group.

[0064] Still Figure 3As shown, the positive input terminal of DC-DC converter circuit 1 is connected to the positive DC bus BUS+ through fuse F13, and the negative input terminal of DC-DC converter circuit 1 is connected to the negative DC bus BUS- through fuse F14. The positive input terminal of DC-DC converter circuit 2 is connected to the positive DC bus BUS+ through fuse F23, and the negative input terminal of DC-DC converter circuit 2 is connected to the negative DC bus BUS- through fuse F24.

[0065] In order to ensure that the fuse blows when a short circuit occurs at the input terminal of the DC-DC converter circuit 120, while the AC-DC converter circuit 110 operates normally, it is necessary to ensure that the Joule integral of the fuse in the fuse group corresponding to the DC-DC converter circuit 120 is less than the Joule integral before the arc of the fuse in the fuse group corresponding to the AC-DC converter circuit 110.

[0066] In one embodiment, each AC-DC converter circuit 110 in the charging system 100 also corresponds to a fifth fuse group, which includes three fuses. The first input terminal of each AC-DC converter circuit 110 is connected to the first fuse in the fifth fuse group, the second input terminal of each AC-DC converter circuit 110 is connected to the second fuse in the fifth fuse group, and the third input terminal of each AC-DC converter circuit 110 is connected to the third fuse in the fifth fuse group.

[0067] Still Figure 3 As shown, the first input terminal of AC-DC converter circuit 1 is connected to terminal U via fuse F51, the second input terminal of AC-DC converter circuit 1 is connected to terminal V via fuse F52, and the third input terminal of AC-DC converter circuit 1 is connected to terminal W via fuse F53. Similarly, the first input terminal of AC-DC converter circuit 2 is connected to terminal U via fuse F54, the second input terminal of AC-DC converter circuit 2 is connected to terminal V via fuse F55, and the third input terminal of AC-DC converter circuit 2 is connected to terminal W via fuse F56.

[0068] The above method can be used to protect the AC-DC converter circuit 110 from input damage, preventing the failure of the AC-DC converter circuit 110 from spreading to the power grid.

[0069] Figure 4 This is another schematic diagram of the charging system provided in an embodiment of this application. In one embodiment, as shown... Figure 4As shown, the auxiliary fuse module 130 can also use a supercapacitor C3 for energy storage. One end of the supercapacitor C3 is connected to the positive terminal of the auxiliary fuse module 130, and the other end is connected to the negative terminal of the auxiliary fuse module 130. Based on this, the number and structure of the AC-DC converter circuit 110 and the DC-DC converter circuit 120 in the charging system 100 can be referenced. Figure 3 The principles are extended here, and the embodiments of this application will not be described in detail.

[0070] In one embodiment, when the charging system 100 includes a greater number of AC-DC converter circuits 110 and / or DC-DC converter circuits 120, the fuse protection principle for short circuits at the output terminals of each AC-DC converter circuit 110 or the input terminals of each DC-DC converter circuit 120 is the same as described above. Figure 3 The descriptions of some parts are similar, and the embodiments in this application will not be repeated here.

[0071] In summary, this application provides a charging system 100, applied in the field of energy technology. The charging system 100 includes at least two AC-DC converter circuits 110, at least two first fuse groups, at least one DC-DC converter circuit 120, and an auxiliary fuse module 130. Each first fuse group includes two fuses. The input terminal of each AC-DC converter circuit 110 is connected to an AC power source. The positive output terminal of each AC-DC converter circuit 110 is connected to the positive DC bus BUS+ through one fuse in its corresponding first fuse group. The negative output terminal of each AC-DC converter circuit 110 is connected to the negative DC bus BUS- through the other fuse in its corresponding first fuse group. The positive input terminal of the DC-DC converter circuit 120 is connected to the positive DC bus BUS+, and the negative input terminal of the DC-DC converter circuit 120 is connected to the negative DC bus BUS-. The positive terminal of the auxiliary fuse module 130 is connected to the positive DC bus BUS+, and the negative terminal is connected to the negative DC bus BUS-. The auxiliary fuse module 130 is used to output an auxiliary fuse current in the event of a short circuit at the output terminal of the AC-DC converter circuit 110. This auxiliary fuse current is greater than or equal to the short-circuit current at the output terminal of the AC-DC converter circuit 110. Based on this, the AC-DC converter circuit with a short circuit at its output can be removed more reliably when multiple AC-DC converter circuits are connected in parallel to the DC bus.

[0072] Those skilled in the art will understand that, for the sake of convenience and brevity, the specific working processes of the systems, devices, and modules described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here.

[0073] In the several embodiments provided in this application, it should be understood that the disclosed apparatus can be implemented in other ways. For example, the apparatus embodiments described above are merely illustrative; multiple modules or components may be combined or integrated into another system, or some features may be omitted or not performed.

[0074] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A charging system, characterized in that, The charging system includes: At least two AC-DC converter circuits and at least two first fuse groups, each first fuse group including two fuses, the input terminal of each AC-DC converter circuit is used to connect to an AC power supply, the positive output terminal of each AC-DC converter circuit is connected to a positive DC bus through one fuse in a corresponding first fuse group, and the negative output terminal of each AC-DC converter circuit is connected to a negative DC bus through another fuse in a corresponding first fuse group; At least one DC-DC converter circuit, wherein the positive input terminal of the DC-DC converter circuit is connected to the positive DC bus, and the negative input terminal of the DC-DC converter circuit is connected to the negative DC bus; An auxiliary fuse module is provided, wherein the positive terminal of the auxiliary fuse module is connected to the positive DC bus, and the negative terminal of the auxiliary fuse module is connected to the negative DC bus. The auxiliary fuse module is used to output an auxiliary fuse current when the output terminal of the AC-DC converter circuit is short-circuited. The auxiliary fuse current is greater than or equal to the short-circuit current at the output terminal of the AC-DC converter circuit.

2. The charging system according to claim 1, characterized in that, The auxiliary fuse module includes a first capacitor, a second capacitor, a first voltage equalizing resistor, and a second voltage equalizing resistor. The first capacitor and the second capacitor are connected in series between the positive terminal and the negative terminal of the auxiliary fuse module. The first voltage equalizing resistor is connected in parallel with the first capacitor, and the second voltage equalizing resistor is connected in parallel with the second capacitor.

3. The charging system according to claim 1, characterized in that, The auxiliary fuse module includes a supercapacitor, one end of which is connected to the positive terminal of the auxiliary fuse module, and the other end of which is connected to the negative terminal of the auxiliary fuse module.

4. The charging system according to any one of claims 1 to 3, characterized in that, The auxiliary fuse module also includes a second fuse group, which includes two fuses; The positive terminal of the auxiliary fuse module is connected to the positive DC bus through one of the fuses in the second fuse group, and the negative terminal of the auxiliary fuse module is connected to the negative DC bus through another fuse in the second fuse group.

5. The charging system according to claim 4, characterized in that, The second fuse group and the first fuse group are fuse groups of the same specifications.

6. The charging system according to any one of claims 1 to 5, characterized in that, The charging system also includes a bidirectional DC-DC converter circuit and an energy storage battery, wherein the energy storage battery is connected to the positive DC bus and the negative DC bus through the bidirectional DC-DC converter circuit.

7. The charging system according to claim 6, characterized in that, The charging system also includes a third fuse group, which includes two fuses. The bidirectional DC-DC converter circuit is connected to the positive DC bus through one of the fuses in the third fuse group, and the bidirectional DC-DC converter circuit is connected to the negative DC bus through the other fuse in the third fuse group.

8. The charging system according to any one of claims 1 to 7, characterized in that, The charging system further includes at least one fourth fuse group, which is connected one-to-one with the at least one DC-DC converter circuit. Each fourth fuse group includes two fuses. The positive input terminal of the DC-DC converter circuit is connected to the positive DC bus through one of the fuses in the fourth fuse group, and the negative input terminal of the DC-DC converter circuit is connected to the negative DC bus through the other fuse in the fourth fuse group.

9. The charging system according to claim 8, characterized in that, The fusing Joule integral value of the fuse in the fourth fuse group is less than the arc-precession Joule integral value of the fuse in the first fuse group.

10. The charging system according to any one of claims 1 to 9, characterized in that, When the number of AC-DC converter circuits is greater than or equal to three, the pre-arc Joule integral value of the fuse in the first fuse group is greater than one-quarter of the fusing Joule integral value of the fuse in the first fuse group.

Images