Step-down circuit of inverter and inverter

Abstract

The utility model provides a step-down circuit of an inverter and the inverter. The step-down circuit comprises at least one power tube group, at least one group of radiators, a first hollow power inductor and a second hollow power inductor, the power tube group comprises an upper bridge arm power tube group and a lower bridge arm power tube group which are connected in series; the upper bridge arm power tube group is used for connecting a high-voltage side of a bus, and the lower bridge arm power tube group is used for connecting a low-voltage side of the bus or grounding; the middle of the upper bridge arm power tube group is connected with one end of a first hollow power inductor; the middle of the lower bridge arm power tube group is connected with one end of a second hollow power inductor; the upper bridge arm power tube group and the lower bridge arm power tube group are respectively provided with a first radiator and a second radiator. Heat dissipation channels between heat dissipation fins of the first radiator and the second radiator respectively correspond to the hollow parts of the corresponding hollow power inductors. The step-down circuit of the utility model can flexibly adjust the power tube group and the radiator according to the size of the load, so as to meet the heat radiation requirements of different power sections.

Description

Technical Field

[0001] The embodiments of the present disclosure relate to the technical field, and in particular to a buck circuit of an inverter and an inverter. Background Art

[0002] A PCS is a bidirectional, current-controlled converter that connects an energy storage battery system to the grid or load. It typically consists of a boost circuit, a buck circuit, and an inverter bridge circuit. The boost circuit boosts the DC voltage of the solar cell to the DC voltage required for inverter output control. The buck circuit accurately and rapidly adjusts the voltage, frequency, and power between the grid and the energy storage system, achieving constant power and constant current charging and discharging, smoothing out fluctuating power output and reducing instantaneous power variations. The inverter bridge circuit converts the boosted DC voltage into an AC voltage of a common frequency, shaving peaks and filling valleys. To address the long charging times and alleviate user anxiety about charging and range, the development of high-power charging technology has gained widespread consensus among industry participants both domestically and internationally, and has already achieved commercial application.

[0003] Currently, most high-power inverters in the industry layout the boost circuit, buck circuit and inverter circuit on a single PCB, resulting in concentrated heat. Furthermore, the power tubes and heat sinks cannot be flexibly configured according to the load size. During high-power charging operation or long-term continuous operation at high temperatures, the cooling fan will accelerate, the noise will become louder, and foreign matter such as dust in the air will quickly adhere to the power conversion devices and heat sinks of each circuit, reducing the heat dissipation effect and affecting charging efficiency. For cleaning and maintenance, staff need to disassemble the entire inverter and fan together, making the maintenance process more troublesome. Utility Model Content

[0004] The purpose of the embodiments of the present disclosure is to provide a step-down circuit of an inverter and an inverter, thereby solving the aforementioned problems existing in the prior art.

[0005] In order to achieve the above objectives, the technical solutions adopted in the embodiments of the present disclosure are as follows:

[0006] In one aspect, an embodiment of the present disclosure provides a step-down circuit for an inverter, which is applied to an inverter. The step-down circuit includes: at least one power tube group, at least one heat sink group, a first air-core power inductor, and a second air-core power inductor; the heat sink group includes: a first heat sink and a second heat sink;

[0007] The power tube group includes: an upper bridge arm power tube group and a lower bridge arm power tube group connected in series;

[0008] The upper bridge arm power tube group is used to connect to the high voltage side of the bus, and the lower bridge arm power tube group is used to connect to the low voltage side of the bus or ground;

[0009] The middle of the upper bridge arm power tube group is connected to one end of the first hollow power inductor, and the middle of the lower bridge arm power tube group is connected to one end of the second hollow power inductor; the other end of the first hollow power inductor is used to connect to the positive electrode of the energy storage battery, and the other end of the second hollow power inductor is used to connect to the negative electrode of the energy storage battery;

[0010] A first radiator is provided on the upper bridge arm power tube group, and a second radiator is provided on the lower bridge arm power tube group. The heat dissipation channels between the heat dissipation fins of the first radiator correspond to the hollowness of the first hollow power inductor, and the heat dissipation channels between the heat dissipation fins of the second radiator correspond to the hollowness of the second hollow power inductor.

[0011] Exemplarily, the step-down circuit includes: a power tube group and a heat sink; the upper arm power tube group includes: a first power tube and a second power tube connected in series; the lower arm power tube group includes: a third power tube and a fourth power tube connected in series;

[0012] The drain of the first power tube is used to connect to the high-voltage side of the busbar, the source of the first power tube is connected to the second power tube, the third power tube and the fourth power tube in sequence, the source of the fourth power tube is used to connect to the low-voltage side of the busbar or ground; the neutral line of the busbar is connected between the second power tube and the third power tube;

[0013] The first hollow power inductor is connected between the first power tube and the second power tube, and the second hollow power inductor is connected between the third power tube and the fourth power tube.

[0014] Exemplarily, the step-down circuit includes: two power tube groups connected in parallel and two heat sinks; the two power tube groups are a first power tube group and a second power tube group, and the two heat sinks are a first heat sink group and a second heat sink group, respectively. The first heat sink group and the second heat sink group include two heat sinks.

[0015] The first power tube group includes: a first upper bridge arm power tube group and a first lower bridge arm power tube group connected in series;

[0016] The first upper bridge arm power tube group includes: a first power tube and a second power tube connected in series, and the first lower bridge arm power tube group includes: a third power tube and a fourth power tube connected in series;

[0017] The drain of the first power tube is used to connect to the high-voltage side of the busbar, the source of the first power tube is connected to the second power tube, the third power tube and the fourth power tube in sequence, the source of the fourth power tube is used to connect to the low-voltage side of the busbar or ground; the neutral line of the busbar is connected between the second power tube and the third power tube;

[0018] The second power tube group includes: a second upper bridge arm power tube group and a second lower bridge arm power tube group connected in series;

[0019] The second upper bridge arm power tube group includes: a fifth power tube and a sixth power tube connected in series, and the second lower bridge arm power tube group includes: a seventh power tube and an eighth power tube connected in series;

[0020] The drain of the fifth power tube is used to connect to the high-voltage side of the busbar, the source of the fifth power tube is connected to the sixth power tube, the seventh power tube and the eighth power tube in sequence, the source of the eighth power tube is used to connect to the low-voltage side of the busbar or ground; the neutral line of the busbar is connected between the sixth power tube and the seventh power tube;

[0021] The first hollow power inductor is connected between the first power tube and the second power tube, and between the fifth power tube and the sixth power tube, and the second hollow power inductor is connected between the third power tube and the fourth power tube, and between the seventh power tube and the eighth power tube;

[0022] The two heat sinks of the first heat sink group are respectively provided on the first power tube, the second power tube, the third power tube and the fourth power tube;

[0023] The two heat sinks of the second heat sink group are respectively arranged on the fifth power tube and the sixth power tube, and the seventh power tube and the eighth power tube.

[0024] Exemplarily, the heat sink provided for the first power tube and the second power tube in the first group of heat sinks and the heat sink provided for the fifth power tube and the sixth power tube in the second group of heat sinks are respectively provided on both sides of the first hollow power inductor, and the heat dissipation channels of the heat dissipation fins on at least opposite sides of the two heat sinks correspond to the hollow core of the first hollow power inductor;

[0025] The heat sink provided on the third power tube and the fourth power tube in the second group of heat sinks and the heat sink provided on the seventh power tube and the eighth power tube in the second group of heat sinks are respectively provided on both sides of the second hollow power inductor, and the heat dissipation channels of the heat dissipation fins on at least one opposite side of the two heat sinks correspond to the hollow core of the second hollow power inductor.

[0026] Exemplarily, according to the charging power of the load, the buck circuit is provided with a corresponding number of power tube groups and heat sinks.

[0027] For example, when the charging power of the load is 50KW~35KW, the step-down circuit is provided with two parallel power tube groups and two radiators; when the charging power of the load is 35KW~15KW, the step-down circuit is provided with one power tube group and one radiator.

[0028] Another aspect of the present disclosure provides an inverter, comprising: the buck circuit of the inverter as described above, a mounting shell, and a heat dissipation structure; the mounting shell has a mounting cavity;

[0029] The heat dissipation structure includes: a support plate, which is detachably arranged in the mounting shell, and the support plate divides the mounting cavity into a first assembly cavity and a second assembly cavity;

[0030] In the first assembly cavity, the step-down circuit is provided on the side wall of the mounting shell opposite to the support plate;

[0031] a fan fixing plate having at least one opening, wherein a fan is provided in the opening, and wherein the fan fixing plate is detachably provided on the support plate;

[0032] The wind direction of the fan is parallel to the wind duct formed by the heat dissipation channels between the heat dissipation fins of at least one group of heat sinks of the step-down circuit and the hollow cores of the corresponding hollow power inductors.

[0033] Exemplarily, the inverter further includes: an inverter bridge circuit and a boost circuit; the inverter bridge circuit is arranged on a side of the support plate facing the buck circuit, and the boost circuit is arranged on a side wall of the mounting shell where the buck circuit is arranged;

[0034] The inverter bridge circuit and the boost circuit are respectively provided with at least one inverter bridge circuit radiator and a boost circuit radiator, and the wind direction of the fan is parallel to the fins of the corresponding radiator.

[0035] Exemplarily, the inverter bridge circuit radiator is respectively arranged opposite to the corresponding boost circuit radiator and the step-down circuit radiator, and a preset heat dissipation channel is provided between the two opposite heat dissipators; the wind direction of the fan is used to be parallel to the corresponding preset heat dissipation channel.

[0036] Exemplarily, one end of the support plate is folded toward the second assembly cavity to form a first folded portion, and the first folded portion is evenly provided with a plurality of first installation openings;

[0037] The fan fixing plate includes: an open accommodating cavity, wherein a side wall in a central region of the accommodating cavity is provided with at least one opening; an end portion of an edge side wall of the accommodating cavity is folded outward to form a second folded portion, wherein the second folded portion is evenly provided with a plurality of second mounting openings;

[0038] The first folding portion corresponds to the second folding portion, and the first mounting opening is fastened to the corresponding second mounting opening by means of bolts.

[0039] The beneficial effects of the embodiments of the present disclosure are:

[0040] The step-down circuit of the disclosed embodiment can flexibly configure the power tube and the heat sink according to the charging power of the load to meet the charging and heat dissipation requirements of different power ranges. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 This is a schematic diagram of a buck circuit structure of an inverter provided by an embodiment of the present disclosure;

[0042] Figure 2 1 is a schematic structural diagram of another embodiment of a step-down circuit of an inverter provided by an embodiment of the present disclosure;

[0043] Figure 3 This is a schematic structural diagram of a heat dissipation portion in a buck circuit of an inverter provided by an embodiment of the present disclosure;

[0044] Figure 4 This is a structural schematic diagram of the heat dissipation portion of another embodiment of a buck circuit of an inverter provided by an embodiment of the present disclosure;

[0045] Figure 5 is a control block diagram of an inverter provided by an embodiment of the present disclosure;

[0046] Figure 6 This is a schematic diagram of the internal structure of an inverter provided by an embodiment of the present disclosure without a fan installed;

[0047] Figure 7 This is a schematic diagram of the internal structure of an inverter provided by an embodiment of the present disclosure after a fan is installed;

[0048] Figure 8 1 is a schematic structural diagram of a heat dissipation structure of an inverter provided by an embodiment of the present disclosure;

[0049] Figure 9 The present invention is a schematic structural diagram of a fan fixing plate of an inverter provided in an embodiment of the present disclosure.

[0050] In the figure,

[0051] 100. Buck circuit; 110. First hollow power inductor; 120. Second hollow power inductor; 200. Power tube group; 210. Upper bridge arm power tube group; 220. Lower bridge arm power tube group; 300. Radiator; 310. First radiator; 320. Second radiator; 400. Mounting shell; 500. Heat dissipation structure; 510. Support plate; 511. First folding portion; 512. First mounting port; 520. Fan fixing plate; 521. Accommodating cavity; 522. Opening; 523. Second folding portion; 524. Second mounting port; 530. Fan; 600. Inverter bridge circuit; 700. Boost circuit; 800. Low-power control circuit; 900. Preset heat dissipation channel. DETAILED DESCRIPTION

[0052] In order to make the purpose, technical solutions and advantages of the embodiments of the present disclosure more clear, the embodiments of the present disclosure are further described in detail below with reference to the accompanying drawings. It should be understood that the specific implementation methods described herein are only used to explain the embodiments of the present disclosure and are not intended to limit the embodiments of the present disclosure.

[0053] like Figures 1 to 4 As shown, the embodiment of the present disclosure proposes a buck circuit for an inverter, which is applied to the inverter. The buck circuit 100 includes: at least one power tube group 200, at least one heat sink 300, a first hollow power inductor 110 and a second hollow power inductor 120; a heat sink 300 includes: a first heat sink 310 and a second heat sink 320; the power tube group 200 includes: an upper bridge arm power tube group 210 and a lower bridge arm power tube group 220 connected in series; the upper bridge arm power tube group 210 is used to connect to the high voltage side of the bus, and the lower bridge arm power tube group 220 is used to connect to the low voltage side of the bus or ground; the upper bridge arm power tube group 210 is connected to the first hollow power inductor 110 in the middle. One end of the inductor 110, the middle of the lower bridge arm power tube group 220 is connected to one end of the second hollow power inductor 120; the other end of the first hollow power inductor 110 is used to connect the positive electrode of the energy storage battery, and the other end of the second hollow power inductor 120 is used to connect the negative electrode of the energy storage battery; a first radiator 310 is provided on the upper bridge arm power tube group 210, and a second radiator 320 is provided on the lower bridge arm power tube group 220. The heat dissipation channel between the heat dissipation fins of the first radiator 310 corresponds to the hollow part of the first hollow power inductor 110, and the heat dissipation channel between the heat dissipation fins of the second radiator 320 corresponds to the hollow part of the second hollow power inductor 120.

[0054] In the disclosed embodiment, the energy storage battery is connected to a step-down circuit, and the output of the step-down circuit is connected to a load via a third capacitor C2 and a fourth capacitor C4 on the DC bus. The step-down circuit in the disclosed embodiment further includes a first capacitor C1 and a second capacitor C3. The upper and lower power tube groups are connected to the bus neutral line, and the bus neutral line is connected between the first capacitor C1 and the second capacitor C3. The first capacitor C1 is connected in parallel with some of the power tubes in the upper and lower power tube groups, and the second capacitor C3 is connected in parallel with some of the power tubes in the upper and lower power tube groups. A first heat sink and a second heat sink are respectively positioned above the upper and lower power tube groups to absorb heat generated by the power tubes and carry it away from the inverter with the fan's wind, achieving heat dissipation. The heat dissipation channels between the heat sink fins correspond to the hollow cores of the corresponding hollow power inductors. Thus, the fan-blown wind passes through the heat dissipation channels of the heat sink and the air ducts formed by the hollow cores of the power inductors, dissipating heat generated by the power tubes and the power inductors, thereby improving heat dissipation.

[0055] The buck circuit of the disclosed embodiment is configured with a corresponding number of power tube groups and heat sinks based on the charging power of the load. That is, in a high-power conversion system, by configuring multiple power tubes in parallel, the current carrying capacity can be improved, the output power can be increased, and the heat dissipation function can be improved while increasing the output power. When the charging power of the load is 50KW to 35KW, the buck circuit is configured with two power tube groups and two heat sinks respectively; when the charging power of the load is 35KW to 15KW, the buck circuit is configured with one power tube group and one heat sink respectively. Specifically, when the load charging power is high power, the input voltage of the step-down circuit is 800V, with N, the output is 150V~170V, the output current is 1A~80A, and the output power is 40KW. At this time, two sets of parallel power tube groups and two sets of radiators are set; when the load charging power is low power, the input voltage of the step-down circuit is 800V, with N, the output is 150V~750V, the output current is 25A~130A, and the output power is 20KW. At this time, one set of power tube groups and one set of radiators can be set.

[0056] like Figure 2 and Figure 4As shown, as a specific example of a step-down circuit, the step-down circuit 100 includes: a group of power tube groups 200 and a group of heat sinks 300. The step-down circuit 100 includes: a group of power tube groups 200 and a group of heat sinks 300. The upper arm power tube group 210 includes: a first power tube and a second power tube connected in series, and the lower arm power tube group 220 includes: a third power tube and a fourth power tube connected in series; the drain of the first power tube is used to connect to the high-voltage side of the bus, the source of the first power tube is connected to the second power tube, the third power tube and the fourth power tube in sequence, and the source of the fourth power tube is used to connect to the low-voltage side of the bus or ground; the neutral line of the bus is connected between the second power tube and the third power tube; the first hollow power inductor 110 is connected between the first power tube and the second power tube, and the second hollow power inductor 120 is connected between the third power tube and the fourth power tube.

[0057] Specifically, the drain D of the first power tube is used to connect to the high-voltage side of the bus, the source S of the first power tube is connected to the drain D of the second power tube, and the gate G of the first power tube is grounded; the source S of the second power tube is used to connect to the neutral line of the bus, and the gate G of the second power tube is grounded; the drain D of the third power tube is connected to the source S of the second power tube, the source S of the third power tube is connected to the drain D of the fourth power tube, and the gate G of the third power tube is grounded; the source S of the fourth power tube is used to connect to the low-voltage side of the bus or ground, and the gate G of the fourth power tube is grounded.

[0058] When the step-down circuit is provided with a group of power tubes and a group of heat sinks, the fins on both sides of each heat sink can face the hollow core of the corresponding hollow power inductor. In this way, the channels of the two adjacent fins and the hollow core form an air duct, which blows away the heat generated by the power tubes and power inductors along with the wind from the fan, thereby improving the heat dissipation efficiency.

[0059] like Figure 1 and Figure 3As shown in the figure, as a specific example of a step-down circuit, the step-down circuit includes: two power tube groups connected in parallel and two groups of heat sinks; the two power tube groups are respectively a first power tube group and a second power tube group, and the two groups of heat sinks are respectively a first heat sink group and a second heat sink group, and the first heat sink group and the second heat sink group each include two heat sinks; the first power tube group includes: a first upper arm power tube group and a first lower arm power tube group connected in series; the first upper arm power tube group includes: a first power tube and a second power tube connected in series, and the first lower arm power tube group includes: a third power tube and a fourth power tube connected in series; the drain of the first power tube is used to connect to the high voltage side of the bus, the source of the first power tube is connected to the second power tube, the third power tube and the fourth power tube in sequence, and the source of the fourth power tube is used to connect to the low voltage side of the bus or ground; the neutral line of the bus is connected between the second power tube and the third power tube; the second power tube group includes: a second upper arm power tube group and a second lower arm power tube group connected in series; the second upper arm power tube group The power tube group includes: a fifth power tube and a sixth power tube connected in series; the second lower bridge arm power tube group includes: a seventh power tube and an eighth power tube connected in series; the drain of the fifth power tube is used to connect to the high-voltage side of the bus, the source of the fifth power tube is connected to the sixth power tube, the seventh power tube, and the eighth power tube in sequence, and the source of the eighth power tube is used to connect to the low-voltage side of the bus or to ground; the neutral line of the bus is connected between the sixth power tube and the seventh power tube; the first hollow power inductor is connected between the first power tube and the second power tube, and between the fifth power tube and the sixth power tube, and the second hollow power inductor is connected between the third power tube and the fourth power tube, and between the seventh power tube and the eighth power tube; the two heat sinks of the first group of heat sinks are respectively provided on the first power tube and the second power tube, and on the third power tube and the fourth power tube; the two heat sinks of the second group of heat sinks are respectively provided on the fifth power tube and the sixth power tube, and on the seventh power tube and the eighth power tube.

[0060] The buck circuit of the disclosed embodiment can be applied to a high-power conversion system. By setting multiple power tubes in parallel, the current carrying capacity can be improved and the output power can be increased. Figure 1In the three-level synchronous rectification buck topology, the 800V bus voltage is divided in series by capacitors C2 and C4. The first power tube Q1 and the fifth power tube Q4 in the upper bus are connected in parallel as upper tubes, the second power tube Q2 and the sixth power tube Q3 are connected in parallel as lower tubes, the fourth power tube Q7 and the eighth power tube Q8 in the lower bus are connected in parallel as upper tubes, and the third power tube Q5 and the seventh power tube Q6 are connected in parallel as lower tubes. When laying out the PCB, the first power tube Q1 on the upper bus and the fifth power tube Q4 on the lower bus are placed in a heat sink. On chip A, the upper second power tube Q2 and the lower sixth power tube Q3 are arranged on a heat sink A1; the upper fourth power tube Q7 and the lower third power tube Q5 of the lower bus are arranged on a heat sink B, and the upper eighth power tube Q8 and the lower seventh power tube Q6 are arranged on a heat sink B1. In this way, A and A1 are connected in parallel, and B and B1 are connected in parallel. Radiators A and B can be regarded as the first group of radiators, and radiators A1 and B1 can be regarded as the second group of radiators.

[0061] According to the combination of the on and off states of the two power tube groups, the buck circuit can have the following four working states (a) to (d):

[0062] (a) Operating State 1: Switches Q1, Q4, Q7, and Q8 are on, while switches Q2, Q3, Q5, and Q6 are off. The input power (bus) charges C1 and C3 through the circuit formed by inductors L1, L2, Q1, Q4, Q7, and Q8, while also providing energy to the load. Power transistors are also known as switching transistors. (b) Operating State 2: Switches Q1, Q4, Q5, and Q6 are on, while Q2, Q3, Q7, and Q8 are off. The circuit formed by inductors L1, L2 and Q1, Q4, Q5, and Q6 provides energy to the load. (c) Operating State 3: Switches Q2, Q3, Q7, and Q8 are on, while Q1, Q4, Q5, and Q6 are off. The circuit formed by inductors L1, L2, Q2, Q3, Q7, and Q8 provides energy to the load. (d) Working state 4: Switches Q2, Q3, Q5, and Q6 are turned on, while switches Q1, Q4, Q7, and Q8 are turned off. Inductors L1, L2, C1, and C3 provide energy to the load.

[0063] In practical applications, when the load power is large, such as 40KW, use A and A1, B and B1. When the load power is small, such as 20KW, use A and B or A1 and B1. The heat sink and power tube are reasonably matched and combined to reflect flexible configuration. The control strategy of the two-stage energy storage converter of the three-level topology of the embodiment of the present disclosure is: As mentioned above, DC / DC is a bidirectional three-level buck-boost circuit, which is used to widen the input voltage range of the energy storage transformer and control the bidirectional flow of energy storage battery power to realize charging and discharging functions. Its control block diagram is as follows: Figure 5As shown in the figure: Pref is the setpoint power value of the energy storage battery; positive values ​​represent discharge, negative values ​​represent charge; Ubat is the energy storage battery voltage; ibat is the sampled battery output current. The DC / DC control strategy adopts single-loop current control. A traditional PI controller is used to control the energy storage battery output current to follow the setpoint, achieving bidirectional power flow. As previously mentioned, the control signals of the upper and lower groups of switches in a three-level DC / DC system differ by half a switching cycle. That is, the carriers of the modulation components PWM1 and PWM2 differ by 180°, controlling Q1, Q4, Q2, Q3, Q5, Q6, and Q7, Q8, respectively. When Pref is positive, the DC / DC system operates in a boost mode, with the energy storage battery discharging at a constant current and power flowing from the energy storage to the grid. At this time, the PWM pulse signal controls switches Q2, Q3, Q7, and Q8, while Q1, Q4, Q5, and Q6 are locked. Only the diodes connected in parallel with them provide freewheeling. When Pref is a negative value, the DC / DC operates in the buck state and the energy storage battery is charged at a constant current. Power flows from the grid to the energy storage. At this time, the PWM pulse signal controls the operation of the switches Q1, Q4, Q5, and Q6. Q2, Q3, Q7, and Q8 are in a locked state, and only the diodes connected in parallel with them play a freewheeling role.

[0064] The heat sink of the disclosed embodiment includes a fixing plate and a plurality of parallel cooling fins disposed on either side of one end of the fixing plate. The fixing plate's other end, adjacent to the cooling fins on either side, forms a reserved space for accommodating power tubes. The fixing plate's other end is used to secure the step-down circuit to the PCB, minimizing the area occupied by the step-down circuit. The cooling fins can be extended or shortened as needed.

[0065] like Figure 3 As shown, the heat sink provided on the first power tube and the second power tube in the first group of heat sinks and the heat sink provided on the fifth power tube and the sixth power tube in the second group of heat sinks are respectively provided on both sides of the first hollow power inductor, and the heat dissipation channels of the heat dissipation fins on at least one opposite side of the two heat sinks correspond to the hollow core of the first hollow power inductor; the heat sink provided on the third power tube and the fourth power tube in the second group of heat sinks and the heat sink provided on the seventh power tube and the eighth power tube in the second group of heat sinks are respectively provided on both sides of the second hollow power inductor, and the heat dissipation channels of the heat dissipation fins on at least one opposite side of the two heat sinks correspond to the hollow core of the second hollow power inductor.

[0066] That is, when the step-down circuit is provided with two parallel power tube groups and two heat sinks, heat sink A of the first heat sink group and heat sink B of the second heat sink group are respectively arranged on either side of the first hollow power inductor, and heat sink A1 of one heat sink group and heat sink B1 of the second heat sink group are respectively arranged on either side of the second hollow power inductor. At least the fins on the side opposite to heat sink A and heat sink B are opposite to the hollow core of the first hollow power inductor, and at least the fins on the side opposite to heat sink A1 and heat sink B1 are opposite to the hollow core of the second hollow power inductor. This allows the heat dissipation channel between two adjacent heat sink fins to connect with the hollow core of the hollow power inductor to form an air duct, thereby improving heat dissipation efficiency.

[0067] In an inverter applicable to the buck circuit of the disclosed embodiment, the boost circuit, the buck circuit, and the inverter circuit are independently arranged on three different PCBs and independently fixed. The independent buck circuit is equipped with two independent heat sinks distributed in parallel on the PCB to form an independent air duct in conjunction with the power inductor. The first power tube Q1, the second power tube Q2, the fourth power tube Q7, and the third power tube Q5 form group A; the sixth power tube Q3, the fifth power tube Q4, the eighth power tube Q8, and the seventh power tube Q6 form group B. When high power is required, both groups are installed. When low power is required, only the first power tube group and the first heat sink group A and B, or the second power tube group and the second heat sink group A1 and B1, are installed and fixed to the lower fixing plate.

[0068] The embodiment of the present disclosure flexibly configures the power tube group and heat sink in the step-down circuit according to the charging power of the load, thereby meeting the heat dissipation requirements of charging in different power ranges.

[0069] like Figure 6 As shown, another aspect of the embodiment of the present disclosure provides an inverter, which includes: a buck circuit 100 of the inverter as described above, a mounting shell 400 and a heat dissipation structure 500; the mounting shell 400 has a mounting cavity; the heat dissipation structure 500 includes: a support plate 510, which is detachably arranged in the mounting shell 400, and the support plate 510 divides the mounting cavity into a first assembly cavity and a second assembly cavity; in the first assembly cavity, the buck circuit is arranged on the side wall of the mounting shell 400 opposite to the support plate 510; a fan fixing plate 520, which has at least one opening 522, and a fan 530 is arranged in the opening 522, and the fan fixing plate 520 is detachably arranged on the support plate 510; the wind direction of the fan 530 is parallel to the air duct formed by the heat dissipation channel between the heat dissipation fins of at least one group of radiators of the buck circuit 100 and the hollow core of the corresponding hollow power inductor.

[0070] The fan of the inverter in this disclosed embodiment corresponds to the radiator. The fan's wind direction is parallel to the heat dissipation channel and the air duct formed by the hollow core of the corresponding hollow power inductor to improve heat dissipation efficiency. Adapting fans in different numbers or positions for blowing and exhausting air meets the heat dissipation requirements of high-power charging inverters in different power ranges. The independent fan mounting plate facilitates removal and cleaning of dust from the fan blades.

[0071] The charging distribution circuit design of the inverter in the embodiment of the present disclosure is suitable for high-power charging. The inverter includes a boost circuit, a buck circuit, and an inverter bridge circuit. The three circuits are independently arranged on three different PCB boards. Among them, the independent buck circuit can be equipped with two independent sets of heat sinks and power inductors to form an independent air duct. The power tubes and heat sinks can be flexibly configured according to the size of the battery load, and the fan can be removably fixed using an independent fan fixing plate. The inverter's housing, or mounting housing, includes an upper outer shell, a lower outer shell, a front panel shell, a rear panel shell, a middle fixed support plate, and an independent fan mounting plate. Inside the mounting housing are independent inverter bridge circuit mounting plates and independent fan mounting plates. The middle fixed support plate holds the inverter bridge circuit PCBA. The lower outer shell is used to hold the boost and buck circuit PCBAs. The fan mounting plate has holes for fans and filters. The fan mounting plate is fixed to the outer edge of the middle fixed support plate. When in use, the independent fan mounting plate blows air into the inverter to dissipate heat and facilitates subsequent removal of the fan mounting plate to clean dust and other foreign matter from the fan blades. The front and rear panel shells both utilize a large-area matrix of honeycomb holes. The lower outer shell is enclosed by three outer shells. The mounting housing, formed by the upper outer shell, lower outer shell, front panel shell, and rear panel shell, contains an installation cavity.

[0072] like Figure 6 As shown, as a specific example of an inverter, the inverter further includes: an inverter bridge circuit 600 and a boost circuit 700; the inverter bridge circuit 600 is arranged on a side of the support plate 510 facing the buck circuit, and the boost circuit 700 is arranged on the side wall of the mounting shell 400 where the buck circuit is arranged; the inverter bridge circuit 600 and the boost circuit 700 are respectively provided with at least one inverter bridge circuit radiator and a boost circuit radiator, and the wind direction of the fan 530 is parallel to the fins of the corresponding radiator.

[0073] The boost circuit, buck circuit, and inverter bridge circuit of the inverter of the disclosed embodiment are independently arranged on different PCBs, distributing the heat dissipation area. The boost circuit and buck circuit can be installed on the same side wall of the mounting housing, with the heat sinks arranged parallel to each other.

[0074] like Figure 6 and Figure 7As shown, the inverter further includes: a low-power control circuit 800 , which is arranged on an independent PCB and on a support plate 510 located in the second assembly cavity.

[0075] like Figure 6 As shown, as a specific example of an inverter, the inverter bridge circuit radiator is respectively arranged opposite to the corresponding boost circuit radiator and the radiator of the buck circuit 100, and a preset heat dissipation channel is provided between the two opposite heat sinks; the wind direction of the fan 530 is used to be parallel to the corresponding preset heat dissipation channel 900.

[0076] The radiators are arranged relative to each other, which can save fans and improve the heat dissipation effect of fans.

[0077] like Figures 7 to 9 As shown, as a specific example of a support plate, one end of the support plate 510 is folded toward the second assembly cavity to form a first folded portion 511, and the first folded portion 511 is evenly provided with a plurality of first mounting ports 512; the fan fixing plate 520 includes: an accommodating cavity 521 with an open opening, and the side wall of the central area of ​​the accommodating cavity 521 is provided with at least one opening 522; the end of an edge side wall of the accommodating cavity 521 is folded outward to form a second folded portion 523, and the second folded portion 523 is evenly provided with a plurality of second mounting ports 524; the first folded portion 511 corresponds to the second folded portion 523, and the first mounting port 512 is fastened to the corresponding second mounting port 524 by bolts.

[0078] The support plate and the fan fixing plate of the embodiment of the present disclosure are detachably connected, so that the fan can be cleaned by only removing the fan fixing plate without separating the fan from the inverter.

[0079] The disclosed embodiment increases the heat dissipation area by arranging independent heat dissipation mechanisms for a boost circuit, a buck circuit, and an inverter circuit inside the mounting shell. The independent buck circuit is equipped with two sets of independent heat sinks that cooperate with the power inductor to form an independent air duct, which effectively disperses heat. The power devices and heat sinks can be flexibly configured according to the size of the load. An independent fan system is installed on the outer edge of the middle fixed support plate. When in use, the fan speed is adjusted by a controller according to the inverter working conditions to achieve the purpose of accelerating heat dissipation and reducing noise by blowing air. When cleaning, the fixed cover can be removed, and the fan fixing plate of the fan mechanism can be taken out from the inside of the mounting shell. Foreign matter such as dust on the fan blades can be cleaned without completely separating the fan and the fixing plate. The process is relatively convenient and quick.

[0080] The embodiment of the present disclosure fixes the cooling fan and the filter on an independent fan fixing plate, and then fixes them to the outer edge of the middle fixed support plate. When in use, air is blown or exhausted inside the inverter to achieve the purpose of heat dissipation, and it is convenient to clean and remove dust or other foreign matter on the fan later.

[0081] During use, the independent heat sink of the step-down circuit is combined with the power inductor to form an independent air duct and applied to the inverter. The fan and inverter circuit are connected together. After the inverter is turned on, the controller will adjust the fan speed according to the internal operating temperature to achieve the purpose of heat dissipation and noise reduction. During this process, the filter can block larger foreign objects, while some dust and other foreign objects will adhere to the fan. When cleaning, remove the fan fixing plate from the inverter, install it back on the inverter after cleaning, and then continue to use the machine.

[0082] The above is only a preferred implementation of the embodiment of the present disclosure. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the embodiment of the present disclosure. These improvements and modifications should also be considered within the scope of protection of the embodiment of the present disclosure.

Claims

1. A step-down circuit for an inverter, applied to an inverter, characterized in that: The step-down circuit (100) comprises: at least one power tube group (200), at least one heat sink group (300), a first hollow power inductor (110), and a second hollow power inductor (120); the heat sink group (300) comprises: a first heat sink (310) and a second heat sink (320); The power tube group (200) comprises: an upper bridge arm power tube group (210) and a lower bridge arm power tube group (220) connected in series; The upper bridge arm power tube group (210) is used to connect to the high voltage side of the busbar, and the lower bridge arm power tube group (220) is used to connect to the low voltage side of the busbar or to ground; The upper bridge arm power tube group (210) is connected to one end of the first hollow power inductor (110) in the middle, and the lower bridge arm power tube group (220) is connected to one end of the second hollow power inductor (120) in the middle; the other end of the first hollow power inductor (110) is used to connect to the positive electrode of the energy storage battery, and the other end of the second hollow power inductor (120) is used to connect to the negative electrode of the energy storage battery; A first radiator (310) is provided on the upper bridge arm power tube group (210), and a second radiator (320) is provided on the lower bridge arm power tube group (220); the heat dissipation channels between the heat dissipation fins of the first radiator (310) correspond to the hollowness of the first hollow power inductor (110), and the heat dissipation channels between the heat dissipation fins of the second radiator (320) correspond to the hollowness of the second hollow power inductor (120).

2. The step-down circuit according to claim 1, wherein: The step-down circuit (100) comprises: a power tube group (200) and a heat sink (300); the upper bridge arm power tube group (210) comprises: a first power tube and a second power tube connected in series; the lower bridge arm power tube group (220) comprises: a third power tube and a fourth power tube connected in series; The drain of the first power tube is used to connect to the high-voltage side of the busbar, the source of the first power tube is connected to the second power tube, the third power tube and the fourth power tube in sequence, the source of the fourth power tube is used to connect to the low-voltage side of the busbar or ground; the neutral line of the busbar is connected between the second power tube and the third power tube; The first hollow power inductor (110) is connected between the first power tube and the second power tube, and the second hollow power inductor (120) is connected between the third power tube and the fourth power tube.

3. The step-down circuit according to claim 1, wherein: The step-down circuit (100) comprises: two power tube groups (200) connected in parallel and two heat sink groups (300); the two power tube groups are respectively a first power tube group and a second power tube group; the two heat sink groups are respectively a first heat sink group and a second heat sink group; the first heat sink group and the second heat sink group each comprise two heat sinks; The first power tube group includes: a first upper bridge arm power tube group and a first lower bridge arm power tube group connected in series; The first upper bridge arm power tube group includes: a first power tube and a second power tube connected in series, and the first lower bridge arm power tube group includes: a third power tube and a fourth power tube connected in series; The drain of the first power tube is used to connect to the high-voltage side of the busbar, the source of the first power tube is connected to the second power tube, the third power tube and the fourth power tube in sequence, the source of the fourth power tube is used to connect to the low-voltage side of the busbar or ground; the neutral line of the busbar is connected between the second power tube and the third power tube; The second power tube group includes: a second upper bridge arm power tube group and a second lower bridge arm power tube group connected in series; The second upper bridge arm power tube group includes: a fifth power tube and a sixth power tube connected in series, and the second lower bridge arm power tube group includes: a seventh power tube and an eighth power tube connected in series; The drain of the fifth power tube is used to connect to the high-voltage side of the busbar, the source of the fifth power tube is connected to the sixth power tube, the seventh power tube and the eighth power tube in sequence, the source of the eighth power tube is used to connect to the low-voltage side of the busbar or ground; the neutral line of the busbar is connected between the sixth power tube and the seventh power tube; The first hollow power inductor (110) is connected between the first power tube and the second power tube, and between the fifth power tube and the sixth power tube, and the second hollow power inductor (120) is connected between the third power tube and the fourth power tube, and between the seventh power tube and the eighth power tube; The two heat sinks of the first heat sink group are respectively provided on the first power tube, the second power tube, the third power tube and the fourth power tube; The two heat sinks of the second heat sink group are respectively arranged on the fifth power tube and the sixth power tube, and the seventh power tube and the eighth power tube.

4. The step-down circuit according to claim 3, wherein: The heat sink provided on the first power tube and the second power tube in the first heat sink group and the heat sink provided on the fifth power tube and the sixth power tube in the second heat sink group are respectively provided on both sides of the first hollow power inductor (110), and the heat dissipation channels of the heat dissipation fins on at least one opposite side of the two heat sinks correspond to the hollow core of the first hollow power inductor (110); The heat sinks of the second group of heat sinks provided on the third power tube and the fourth power tube and the heat sinks of the second group of heat sinks provided on the seventh power tube and the eighth power tube are respectively provided on both sides of the second hollow power inductor (120), and the heat dissipation channels of the heat dissipation fins on at least one opposite side of the two heat sinks correspond to the hollow core of the second hollow power inductor (120).

5. The step-down circuit according to any one of claims 1 to 4, characterized in that: According to the charging power of the load, the step-down circuit (100) is provided with a corresponding number of power tube groups and heat sinks.

6. The method according to claim 5, characterized in that When the charging power of the load is 50KW to 35KW, the step-down circuit (100) is provided with two parallel power tube groups and two heat sinks; when the charging power of the load is 35KW to 15KW, the step-down circuit (100) is provided with one power tube group (200) and one heat sink (300).

7. An inverter, characterized in that: The inverter comprises: a step-down circuit (100) of the inverter according to any one of claims 1 to 6, a mounting shell (400), and a heat dissipation structure (500); the mounting shell (400) has a mounting cavity; The heat dissipation structure (500) comprises: a support plate (510) detachably arranged in the installation shell (400), wherein the support plate (510) divides the installation cavity into a first assembly cavity and a second assembly cavity; In the first assembly cavity, the step-down circuit is provided on a side wall of the mounting shell (400) opposite to the support plate (510); A fan fixing plate (520) has at least one opening (522), a fan (530) is provided in the opening (522), and the fan fixing plate (520) is detachably provided on the support plate (510); The wind direction of the fan (530) is parallel to the wind duct formed by the heat dissipation channels between the heat dissipation fins of at least one group of heat sinks of the step-down circuit (100) and the hollow cores of the corresponding hollow power inductors.

8. The inverter according to claim 7, characterized in that: The inverter further comprises: an inverter bridge circuit (600) and a boost circuit (700); the inverter bridge circuit (600) is arranged on a side of the support plate (510) facing the buck circuit (100), and the boost circuit (700) is arranged on a side wall of the mounting shell (400) where the buck circuit is arranged; The inverter bridge circuit (600) and the boost circuit (700) are respectively provided with at least one inverter bridge circuit radiator and a boost circuit radiator, and the wind direction of the fan (530) is parallel to the fins of the corresponding radiator.

9. The inverter according to claim 8, characterized in that: The inverter bridge circuit radiator is respectively arranged opposite to the corresponding boost circuit radiator and the radiator of the buck circuit (100), with a preset heat dissipation channel being provided between the two opposite heat dissipators; the wind direction of the fan (530) is used to be parallel to the corresponding preset heat dissipation channel (900).

10. The inverter according to claim 9, characterized in that: One end of the support plate (510) is folded toward the second assembly cavity to form a first folded portion (511), and the first folded portion (511) is evenly provided with a plurality of first installation openings (512); The fan fixing plate (520) comprises: an open accommodating cavity (521), wherein the side wall of the central region of the accommodating cavity (521) is provided with at least one opening (522); an end portion of an edge side wall of the accommodating cavity (521) is folded outward to form a second folding portion (523), and the second folding portion (523) is evenly provided with a plurality of second mounting openings (524); The first folding portion (511) corresponds to the second folding portion (523), and the first mounting opening (512) is fastened to the corresponding second mounting opening (524) by means of bolts.

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