Photovoltaic inverter

Abstract

The present invention discloses a photovoltaic inverter, including a cabinet and a power module arranged in the cabinet, the power module including an inverter power unit, a first ventilation duct and a second ventilation duct isolated from the first ventilation duct, the inverter power unit is located upstream of the air intake of the first ventilation duct, the first ventilation duct is provided with a first air inlet and a first air outlet, and the second ventilation duct is provided with a second air inlet and a second air outlet. In the photovoltaic inverter provided in the present application, the inverter power unit with a large amount of heat generation adopts an independent air duct for heat dissipation, and is arranged upstream of the first ventilation duct, so that the cold air can dissipate the heat of the inverter power unit in time, thereby improving the heat dissipation efficiency of the inverter power unit.

Description

Technical Field

[0001] The present invention relates to the technical field of electrical equipment, and in particular to a photovoltaic inverter. Background Art

[0002] As the interface device between the solar power generation system and the power grid, the photovoltaic grid-connected inverter must ensure the heat dissipation performance of the inverter power module while ensuring the circuit design and implementation. The heat dissipation performance of the heating module in the photovoltaic inverter has an important impact on the working stability of the entire inverter system, product reliability, and the service life of the power device.

[0003] The specific layout of traditional photovoltaic inverters is relatively complex. In order to ensure the protection level of the whole machine, the advantages of the air duct of the whole machine are sacrificed. The lower side air intake and upper side air outlet are adopted. The devices that are more sensitive to heat (inverter power unit) are placed at the hot air end, and the devices with higher temperature resistance levels (such as reactors) are placed at the cold air end, resulting in lower heat dissipation efficiency of the inverter power unit.

[0004] Therefore, how to improve the heat dissipation efficiency of the inverter power unit is a technical problem that needs to be solved urgently by those skilled in the art. Summary of the invention

[0005] The object of the present invention is to provide a photovoltaic inverter to improve the heat dissipation efficiency of an inverter power unit.

[0006] To achieve the above-mentioned purpose, the present invention provides a photovoltaic inverter, including a cabinet and a power module arranged in the cabinet, the power module including an inverter power unit, a first ventilation duct and a second ventilation duct isolated from the first ventilation duct, the inverter power unit is located upstream of the air intake of the first ventilation duct, the first ventilation duct is provided with a first air inlet and a first air outlet, and the second ventilation duct is provided with a second air inlet and a second air outlet.

[0007] Preferably, it further comprises a reactance unit arranged in the first ventilation duct, wherein only the reactance unit and the inverter power unit are arranged in the first ventilation duct, and along the gas flow direction, the reactance unit is located downstream of the inverter power unit.

[0008] Preferably, a capacitor pool, an AC power distribution unit, and a DC power distribution unit are provided in the second ventilation duct.

[0009] Preferably, the second ventilation duct includes a capacitor pool side duct and a DC side duct, the capacitor pool is provided upstream in the capacitor pool side duct, the AC power distribution unit is provided downstream, and the DC power distribution unit is provided in the DC side duct.

[0010] Preferably, the air inlet of the cabinet is located at the top of the cabinet, the first air inlet and the second air inlet are both located at the top of the power module and connected to the air inlet, and the first air outlet of the first ventilation duct and the second air outlet of the second ventilation duct are both located at the bottom of the cabinet.

[0011] Preferably, the air inlet duct is a side air inlet channel, the side wall of the air inlet duct is arranged in a ring shape around the top circumference of the cabinet, and the side wall of the air inlet duct is provided with a strip-shaped louver air inlet.

[0012] Preferably, the first air inlet is provided with a first fan, the second air inlet is provided with a second fan, and the wind pressure of the first fan is greater than the wind pressure of the second fan, the second ventilation duct is separated from the first ventilation duct by a baffle, and the side air inlet duct portion adjacent to the first air inlet and the side air inlet duct portion adjacent to the adjacent second air inlet are located on two adjacent sides.

[0013] Preferably, the air inlets of the capacitor pool side air duct and the DC side air duct are diagonally arranged, and the air inlet hole of the ventilation duct side wall connected with the capacitor pool side air duct and the DC side air duct is connected with the first air inlet.

[0014] Preferably, there are at least two power modules.

[0015] Preferably, two adjacent power modules are distributed in the cabinet in a mirror-symmetrical manner.

[0016] Preferably, there are two power modules, the first ventilation duct and the capacitor pool side duct of the two power modules are located inside, and the DC side duct of the two power modules are located on two opposite sides of the photovoltaic inverter that are arranged back to back.

[0017] Preferably, the side walls of the first ventilation passages of two adjacent power modules are adjacent, and a water retaining ring is circumferentially provided at the first air inlet, and the top of the water retaining ring is lower than the height of the top of the baffle.

[0018] Preferably, a water retaining groove is provided on the air inlet duct facing the first air inlet and the second air inlet, and the water retaining groove is arranged on the inner side of the side wall of the air inlet duct.

[0019] Preferably, the reactance unit and the AC power distribution unit are located in the middle of the lower part of the cabinet, and the AC power distribution unit includes an AC frame circuit breaker and an AC output wiring copper busbar connected to the AC frame circuit breaker.

[0020] Preferably, the AC power distribution unit further includes an AC fuse.

[0021] Preferably, the AC fuse is located above the AC output wiring copper bar, and the AC fuse and the AC output wiring copper bar are both located on the side of the AC frame circuit breaker.

[0022] Preferably, the DC side air ducts of the two power modules are respectively located on the left and right sides of the cabinet, each DC side air duct is provided with a DC power distribution unit, and the inverter power unit is located between the two DC power distribution units.

[0023] Preferably, the capacitor pool is located directly above the AC distribution unit, the inverter power unit is located directly above the reactance unit, and in the same power module, the inverter power unit, the reactance unit, the capacitor pool and the AC distribution unit are all located on the same side of the DC distribution unit.

[0024] In the above technical scheme, the photovoltaic inverter provided by the present invention includes a cabinet and a power module arranged in the cabinet, the power module includes an inverter power unit, a first ventilation duct and a second ventilation duct isolated from the first ventilation duct, the inverter power unit is located upstream of the air intake of the first ventilation duct, the first air inlet of the first ventilation duct and the second air inlet of the second ventilation duct.

[0025] From the above description, it can be seen that in the photovoltaic inverter provided in the present application, the inverter power unit that generates more heat is cooled by an independent air duct and is arranged upstream of the first ventilation duct, so that the cold air can dissipate the heat of the inverter power unit in time, thereby improving the heat dissipation efficiency of the inverter power unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0027] Figure 1 A top view of a photovoltaic inverter provided by an embodiment of the present invention;

[0028] Figure 2 for Figure 1 The A-direction side view of the left power module shown;

[0029] Figure 3 for Figure 2 The schematic diagram of the structure of the power module along the CC direction is shown;

[0030] Figure 4 for Figure 1 The side view of the left power cabinet module is shown in the direction of B;

[0031] Figure 5 A three-dimensional structural diagram of a photovoltaic inverter skeleton provided by an embodiment of the present invention;

[0032] Figure 6 The structure layout diagram of the air inlet position provided by the embodiment of the present invention;

[0033] Figure 7 A diagram showing the installation position of a water retaining trough provided in an embodiment of the present invention;

[0034] Figure 8 A power module cabinet internal unit layout diagram provided by an embodiment of the present invention;

[0035] Fig. 9 A layout diagram of the lower internal units of two power modules provided in an embodiment of the present invention;

[0036] Fig.10 This is a diagram of the internal unit layout of two power modules provided in an embodiment of the present invention.

[0037] in Figure 1-10 Middle: 1. Inverter power unit; 2. Capacitor pool; 3. DC power distribution unit; 4. Air inlet; 5. First fan; 6. Second fan; 7. Second ventilation duct; 8. First ventilation duct; 9. Reactor unit;

[0038] 10. AC power distribution unit; 10-1. AC fuse; 10-2. AC frame circuit breaker; 10-3. AC output wiring copper bar;

[0039] 11. Copper busbar; 12. Baffle; 13. Water retaining ring; 14. Louver air inlet; 15. Water retaining groove; A1. First power module; A2. Second power module. DETAILED DESCRIPTION

[0040] The core of the present invention is to provide a photovoltaic inverter to improve the heat dissipation efficiency of the inverter power unit.

[0041] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and implementation modes.

[0042] Please refer to Figures 1 to 7 .

[0043] In a specific implementation, the photovoltaic inverter provided by the specific embodiment of the present invention includes a cabinet and a power module arranged in the cabinet, the power module includes an inverter power unit 1, a first ventilation duct 8, and a second ventilation duct 7 isolated from the first ventilation duct 8, the inverter power unit 1 is located upstream of the air intake of the first ventilation duct 8, and the first air inlet of the first ventilation duct 8 and the second air inlet of the second ventilation duct 7. Specifically, the heating modules in the cabinet can be connected through a copper bus 11.

[0044] From the above description, it can be seen that in the photovoltaic inverter provided in the specific embodiment of the present application, the inverter power unit 1 that generates more heat adopts an independent air duct for heat dissipation, and is arranged upstream of the first ventilation duct 8, so that the cold air can dissipate the heat of the inverter power unit 1 in time, thereby improving the heat dissipation efficiency of the inverter power unit 1.

[0045] In a specific embodiment, the photovoltaic inverter further includes a reactance unit 9 disposed in the first ventilation duct 8. Only the reactance unit 9 and the inverter power unit 1 are disposed in the first ventilation duct 8. Along the gas flow direction, the reactance unit 9 is located downstream of the inverter power unit 1. Specifically, the reactance unit 9 can be located directly below the inverter power unit 1. Since the reactance unit 9 has a high temperature resistance level, even if the reactance unit 9 is disposed downstream of the inverter power unit 1, it will not cause much impact on the reactance unit 9, thereby improving the heat dissipation efficiency of the whole machine and reducing the failure rate of the whole machine, saving space, and reducing manufacturing costs and customer use costs.

[0046] Specifically, a capacitor pool 2, an AC power distribution unit 10, and a DC power distribution unit 3 are arranged in the second ventilation duct 7. The AC power distribution unit 10 includes an AC fuse and an AC switch. The DC power distribution unit 3 includes a DC switch and a DC fuse. The capacitor pool 2 is specifically a DC capacitor pool.

[0047] The reactance unit 9 and the AC power distribution unit 10 are located in the middle of the lower part of the cabinet.

[0048] The AC distribution unit includes an AC frame circuit breaker 10-2 and an AC output wiring copper bar 10-3 connected to the AC frame circuit breaker 10-2. That is, the AC switch is an AC frame circuit breaker 10-2 (ACB), which has an electric operation function and does not need to be used with an AC contactor, thereby saving device costs.

[0049] Specifically, the AC power distribution unit 10 also includes an AC fuse 10-1 electrically connected between the AC frame circuit breaker 10-2 and the AC output wiring copper bar 10-3 as an optional component to protect the entire internal system of the photovoltaic inverter. Specifically, the AC fuse 10-1 can be located above the AC output wiring copper bar 10-3. Preferably, the AC fuse 10-1 is located directly above the AC output wiring copper bar 10-3. The AC fuse 10-1 and the AC output wiring copper bar 10-3 are both located on the side of the AC frame circuit breaker 10-2. The overall structure is compact, and the length of the copper bar 11 between adjacent components is reduced.

[0050] Specifically, the AC frame circuit breaker 10 - 2 is located between the AC fuse 10 - 1 and the DC distribution unit 3 .

[0051] In a specific embodiment, the second ventilation duct 7 includes a capacitor pool side duct and a DC side duct, wherein a capacitor pool 2 is provided upstream in the capacitor pool side duct, an AC distribution unit 10 is provided downstream, and a DC distribution unit 3 is provided in the DC side duct.

[0052] In a specific embodiment, the air inlet 4 of the cabinet is located at the top of the cabinet, the first air inlet of the first ventilation duct 8 and the second air inlet of the second ventilation duct 7 are both located at the top of the power module and are connected to the air inlet 4, and the first air outlet of the first ventilation duct 8 and the second air outlet of the second ventilation duct 7 are located at the bottom of the cabinet. The top-in and bottom-out heat dissipation method can better improve the heat dissipation efficiency of the whole machine. Of course, in specific use, it can also be set to the bottom of the cabinet for air inlet, top air outlet, or side air inlet and outlet.

[0053] In order to facilitate the entry of gas, the air inlet 4 is a side air inlet channel, the side wall of the air inlet 4 is arranged in a circular shape at the top of the cabinet, and a strip-shaped louver air inlet 14 is opened on the side wall of the air inlet 4. In order to prevent impurities from entering, the air inlet of the air inlet 4 is provided with waterproof and breathable cotton, and specifically, the waterproof and breathable cotton can be arranged at the position of the louver air inlet 14.

[0054] In order to improve the heat dissipation efficiency, preferably, the air inlet of the first ventilation duct 8 is provided with a first fan 5, the air inlet of the second ventilation duct 7 is provided with a second fan 6, and the wind pressure of the first fan 5 is greater than the wind pressure of the second fan 6, the second ventilation duct 7 is separated from the first ventilation duct 8 by a baffle 12, and the side air inlet channel portion adjacent to the first air inlet of the first ventilation duct 8 and the side air inlet channel portion adjacent to the second air inlet of the adjacent second ventilation duct 7 are located on two adjacent side surfaces. Since the first ventilation duct 8 and the second ventilation duct 7 have different requirements for air volume, and since the inverter power module is more sensitive to heat, the wind pressure is larger to avoid damage to the inverter power module by high temperature.

[0055] Specifically, the baffle 12 is a U-shaped baffle disposed at the second air inlet of the second fan 6 and opening toward the side air inlet passage. The baffle 12 is added to the air inlet of the second fan 6 to reduce the wind grabbing situation between the first fan 5 and the second fan 6. In order to prevent external rainwater from entering the second air inlet, the upper surface of the second air inlet is a sloped surface that gradually increases toward the outer wall of the air inlet 4.

[0056] In order to ensure a large air volume of the first fan 5 , preferably, no baffle is provided at the first air inlet of the first fan 5 .

[0057] Specifically, the first fan 5 and the second fan 6 may be centrifugal fans.

[0058] Since the wind pressures of the first fan 5 and the second fan 6 are different, the side air inlet channel portion adjacent to the first air inlet of the first ventilation duct 8 and the side air inlet channel portion adjacent to the second air inlet of the adjacent second ventilation duct 7 are located on two adjacent side surfaces. Specifically, the air inlets of the capacitor pool side air duct and the DC side air duct are arranged diagonally, and the air inlet holes of the ventilation duct side walls connected to the capacitor pool side air duct and the DC side air duct are connected to the air inlet of the first ventilation duct 8. By arranging multiple side walls of the ventilation duct to be connected to the air inlet of the first ventilation duct 8, the air inlet requirements of the first ventilation duct 8 are guaranteed and effective heat dissipation is achieved.

[0059] like Figure 1 As shown, in a specific implementation manner, there are at least two power modules, and preferably, two adjacent power modules are distributed in the cabinet in a mirror-symmetrical manner.

[0060] Specifically, there are two power modules, the first ventilation duct 8 and the capacitor pool side duct of the two power modules are located inside, and the DC side ducts of the two power modules are located on the opposite sides of the photovoltaic inverter. Specifically, the DC side duct is located on the left and right sides of the cabinet length direction, and the first ventilation duct and the capacitor pool side duct are located in the middle of the two DC side ducts. The overall structure is compact. The interiors of two adjacent first ventilation ducts 8 can be connected or not connected, and the interiors of the two capacitor pool side ducts can be connected or not connected.

[0061] In a specific embodiment, the side walls of the first ventilation ducts 8 of two adjacent power modules are adjacent, and a water retaining ring 13 is provided circumferentially of the first air inlet, and the top of the water retaining ring 13 is lower than the top height of the baffle 12. The water retaining ring 13 is provided at the periphery of the first air inlet to prevent external rainwater from entering the first air inlet.

[0062] like Figures 5 to 7 As shown, specifically, a water retaining groove 15 is provided on the air inlet 4 toward the first air inlet and the second air inlet, and the water retaining groove 15 is provided on the inner side of the side wall of the air inlet 4. Figure 7As shown, the water retaining groove 15 is open at the top, and the bottom end is connected to the louver air inlet 14 of the air inlet 4. Rainwater entering the water retaining groove 15 is discharged through the louver air inlet 14 at the bottom to avoid accumulation in the water groove 15.

[0063] like Figure 1 As shown, the photovoltaic inverter as a whole adopts a mirror-symmetrical structure layout, which is divided into a first power module A1 and a second power module A2. The connection path of the copper bus 11 is as follows: Figure 1 As shown, the path is shorter. Specifically, the copper busbar on the AC output side is compatible.

[0064] In the present application, preferably, in the photovoltaic inverter, except for the inverter power unit 1 and the reactance unit 9, other heat generating devices are located in the second ventilation duct 7. The cold air entering from the top side of the cabinet is introduced into the cavity of the second ventilation duct 7 along the airflow direction of the duct by the second fan 6, and the heat of the heat generating devices in the capacitor pool side duct and the DC side duct are taken away by heat conduction, thereby meeting the heat dissipation of the cavity of the second ventilation duct 7.

[0065] Since the inverter power unit 1 and the reactance unit 9 are located on one side of the middle part of the photovoltaic inverter, and the DC capacitor pool and the AC power distribution are located on the other side of the middle part of the inverter, the air ducts of the two are independent of each other. Such independent air ducts can better utilize the air duct layout according to the heat generation characteristics of each component in the inverter, thereby improving the heat dissipation efficiency of the whole machine and reducing the failure rate of the whole machine.

[0066] like Fig.10 As shown, the DC side air ducts of the two power modules are respectively located on the left and right sides of the cabinet, each DC side air duct is provided with a DC distribution unit 3, and the inverter power unit 1 is located between the two DC distribution units 3. Specifically, the two inverter power units 1 are located at the same height.

[0067] In a specific embodiment, the capacitor pool 2 is located directly above the AC distribution unit 10, and the inverter power unit 1 is located directly above the reactance unit 9. In the same power module, the inverter power unit 1, the reactance unit 9, the capacitor pool 2 and the AC distribution unit 10 are all located on the same side of the DC distribution unit 3.

[0068] Taking the internal unit of a power module as an example, the current direction of the whole machine is: DC distribution unit 3 → capacitor pool 2 → inverter power unit 1 → reactor unit 9 → AC frame circuit breaker 10-2 → AC fuse 10-1 → AC output wiring busbar 10-3. The unit outputs of the two power modules can be connected in parallel or not. Due to the compact layout of the whole machine and the space-saving layout, the connection copper busbar 11 of the whole machine has a shorter path, which can save the cost of the copper busbar 11. Among them, the AC output wiring busbar 10-3 of the two units of the inverter can be selected to be connected in parallel or not, thereby realizing the special customization needs of customers, that is, meeting the low cost demand for the connection of the copper busbar 11 in the photovoltaic inverter and the diversified selection needs of customers.

[0069] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0070] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A photovoltaic inverter, characterized in that: The invention comprises a cabinet and a power module arranged in the cabinet, wherein the power module comprises an inverter power unit (1), a first ventilation duct (8) and a second ventilation duct (7) arranged to be isolated from the first ventilation duct (8), the inverter power unit (1) is located upstream of the air intake of the first ventilation duct (8), the first ventilation duct (8) is provided with a first air inlet and a first air outlet, and the second ventilation duct (7) is provided with a second air inlet and a second air outlet; The second ventilation duct (7) is provided with a capacitor pool (2), an AC power distribution unit (10), and a DC power distribution unit (3); The second ventilation duct (7) comprises a capacitor pool side duct and a DC side duct, the capacitor pool (2) being provided upstream of the capacitor pool side duct, the AC power distribution unit (10) being provided downstream, and the DC power distribution unit (3) being provided in the DC side duct; The air inlet (4) of the cabinet is located at the top of the cabinet, the air inlet (4) is a side air inlet channel, the first air inlet is provided with a first fan (5), and the second air inlet is provided with a second fan (6); The second ventilation duct (7) is separated from the first ventilation duct (8) by a baffle (12), and the side air inlet duct portion adjacent to the first air inlet and the side air inlet duct portion adjacent to the adjacent second air inlet are located on two adjacent side surfaces.

2. The photovoltaic inverter according to claim 1, characterized in that: It also includes an inductor unit (9) arranged in the first ventilation duct (8), wherein only the inductor unit (9) and the inverter power unit (1) are arranged in the first ventilation duct (8), and along the gas flow direction, the inductor unit (9) is located downstream of the inverter power unit (1).

3. The photovoltaic inverter according to claim 1, characterized in that: The first air inlet and the second air inlet are both located at the top of the power module and are connected to the air inlet duct (4); the first air outlet of the first ventilation duct (8) and the second air outlet of the second ventilation duct (7) are both located at the bottom of the cabinet.

4. The photovoltaic inverter according to claim 3, characterized in that: The side wall of the air inlet duct (4) is arranged in a ring shape around the top of the cabinet, and a strip-shaped louver air inlet (14) is provided on the side wall of the air inlet duct (4).

5. The photovoltaic inverter according to claim 4, characterized in that: The wind pressure of the first fan (5) is greater than the wind pressure of the second fan (6).

6. The photovoltaic inverter according to claim 5, characterized in that: The air inlets of the capacitor pool side air duct and the DC side air duct are arranged diagonally, and the air inlet hole of the ventilation duct side wall connected with the capacitor pool side air duct and the DC side air duct is connected with the first air inlet.

7. The photovoltaic inverter according to claim 5, characterized in that: There are at least two power modules.

8. The photovoltaic inverter according to claim 7, characterized in that: And two adjacent power modules are distributed in the cabinet in a mirror-symmetrical manner.

9. The photovoltaic inverter according to claim 7, characterized in that: There are two power modules, the first ventilation duct (8) and the capacitor pool side duct of the two power modules are located inside, and the DC side ducts of the two power modules are located on two opposite sides of the photovoltaic inverter.

10. The photovoltaic inverter according to claim 8, characterized in that: The side walls of the first ventilation passages (8) of two adjacent power modules are adjacent, and a water retaining ring (13) is provided circumferentially of the first air inlet, with the top of the water retaining ring (13) being lower than the height of the top of the baffle (12).

11. The photovoltaic inverter according to claim 8, characterized in that: The air inlet duct (4) is provided with a water retaining groove facing the first air inlet and the second air inlet, and the water retaining groove is arranged on the inner side of the side wall of the air inlet duct (4).

12. The photovoltaic inverter according to claim 8, characterized in that: It also includes a reactance unit (9) arranged in the first ventilation duct (8), the reactance unit (9) and the AC power distribution unit (10) are located in the middle of the lower part of the cabinet, and the AC power distribution unit includes an AC frame circuit breaker (10-2) and an AC output wiring copper busbar (10-3) connected to the AC frame circuit breaker (10-2).

13. The photovoltaic inverter according to claim 12, characterized in that: The AC power distribution unit (10) further comprises an AC fuse (10-1) electrically connected between the AC frame circuit breaker (10-2) and the AC output wiring copper busbar (10-3).

14. The photovoltaic inverter according to claim 13, characterized in that: The AC fuse (10-1) is located above the AC output wiring copper bar (10-3), and both the AC fuse (10-1) and the AC output wiring copper bar (10-3) are located on the side of the AC frame circuit breaker (10-2).

15. The photovoltaic inverter according to claim 12, characterized in that: The DC side air ducts of the two power modules are respectively located on the left and right sides of the cabinet, each DC side air duct is provided with a DC power distribution unit (3), and the inverter power unit (1) is located between the two DC power distribution units (3).

16. The photovoltaic inverter according to any one of claims 1 to 15, characterized in that: It also includes an inductor unit (9) arranged in the first ventilation duct (8), the capacitor pool (2) is located directly above the AC distribution unit (10), the inverter power unit (1) is located directly above the inductor unit (9), and in the same power module, the inverter power unit (1), the inductor unit (9), the capacitor pool (2) and the AC distribution unit (10) are all located on the same side of the DC distribution unit (3).

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