Flexible DC bidirectional buck-boost system architecture method

Abstract

The invention relates to the technical field of direct-current bidirectional buck-boost, in particular to a flexible direct-current bidirectional buck-boost system architecture method, which comprises the following steps that: step 1, the number of battery modules can be flexibly configured for single-cluster batteries: the battery modules are mutually connected to form battery clusters RACK1,..., N, and the battery clusters RACK1,..., N are connected in parallel through the output positive pole and the positive pole of a master control optimizer, so that the battery clusters RACK1,..., N are connected in parallel; the-pole and the-pole are connected in parallel with a common direct-current bus, so that bidirectional energy flow under voltage boosting / voltage reducing is realized; a plurality of battery clusters are connected in parallel to form the battery cluster system, the battery cluster system is used for controlling active balance among the battery clusters, and parallel operation of the battery clusters with different rated voltages can be achieved; and step 3, power isolation: performing power isolation between clusters in the battery cluster system to solve the problem of a wooden barrel short plate effect between the clusters in the battery clusters and greatly improve the actual available capacity of the battery stacks, so that the actual available capacity of the battery stacks can be greatly improved, the scheme is flexible, the application scenarios are diversified, the system stability is improved, and the system reliability is improved. Revenue is increased for clients, and cost is saved.

Description

Technical Field

[0001] The present invention relates to the field of direct current bidirectional buck-boost technology, and in particular to a flexible direct current bidirectional buck-boost system architecture method. Background Art

[0002] Adding a bidirectional main control optimizer to the main control box of a traditional battery cluster can realize bidirectional energy flow under boost / step-down, realize free matching and combination of modules within the battery cluster, and be compatible with flexible combination of battery PACK modules, which is convenient for charge and discharge management and protection of the battery cluster; for multi-cluster parallel battery cluster systems.

[0003] At present, the DC solutions on the market are relatively traditional. When the DC bus of multiple battery clusters is connected in parallel, the inconsistent SOC and voltage lead to unbalanced charging and discharging capacity, as well as bias current and circulating current, resulting in the "short board effect". The inconsistent SOC leads to the inability to fully charge or discharge each battery cluster, and the capacity cannot be fully utilized, and the application scenarios are relatively single. Summary of the invention

[0004] The object of the present invention is to provide a flexible DC bidirectional buck-boost system architecture method to solve the problems raised in the above background technology.

[0005] To achieve the above object, the present invention provides the following technical solution: a flexible DC bidirectional buck-boost system architecture method, comprising the following steps:

[0006] Step 1: The number of battery modules can be flexibly configured in a single battery cluster: the battery modules are connected to form a battery cluster, battery cluster RACK1, ... N, and the + poles are connected in parallel with the + poles, and the - poles are connected in parallel with the - poles to share the DC bus through the output of the main control optimizer, so as to realize the bidirectional flow of energy under boost / buck;

[0007] Step 2, battery cluster system: multiple battery clusters are connected in parallel to form a battery cluster system, which is used to control active balancing between battery clusters and can realize parallel operation of battery clusters with different rated voltages;

[0008] Step 3: Power isolation: Power isolation is performed between clusters in the battery cluster system to solve the "short board effect" between clusters in the battery cluster, greatly improving the actual available capacity of the battery stack.

[0009] Preferably, in the step three, when the DC buses of multiple battery clusters are connected in parallel, the SOC and voltage are inconsistent, resulting in unbalanced charge and discharge capacity, as well as bias current and circulating current, resulting in the short board effect.

[0010] Preferably, a main control box is arranged inside the battery cluster, and the inside of the main control box is connected to the DC bus by input connector B+ / B- terminals, isolating switch, fuse, Hall, main positive KM1, main negative KM2, pre-charge KM3 DC contactor, main control optimizer, main positive KM4 DC contactor and output terminals.

[0011] Preferably, the B+ / B- connection terminal on the left side of the main control box is connected to the battery pack, and passes through the isolating switch, fuse, Hall, main positive KM1, main negative KM2, and pre-charge KM3 DC contactor to the input side of the main control optimizer. The output of the main control optimizer is connected to the output main positive KM4 DC contactor to the P+ / P- output terminal, and the output terminal is connected to the DC bus.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] 1. Adding a master control optimizer in the battery cluster to realize the bidirectional flow of energy under boost / buck to realize the flexible DC bidirectional buck-boost system solution architecture;

[0014] Second, the number of battery modules can be flexibly configured in a single battery cluster;

[0015] 3. Achieve active balancing between battery clusters, and even achieve parallel operation of battery clusters with different rated voltages;

[0016] 4. Solve the "barrel short board effect" between battery clusters and greatly improve the actual available capacity of the battery stack;

[0017] 5. The solution is flexible and has diverse application scenarios, especially suitable for scenarios where the loads of multiple transformers in industrial parks are inconsistent and the loads change frequently. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is the system block diagram of the flexible DC bidirectional buck-boost system architecture.

[0019] Figure 2 Add a main control optimizer primary system diagram for the main control box.

[0020] Figure 3 2 is a system architecture diagram of an embodiment of the present invention.

[0021] Figure 4 Partial operation data and benefit diagram for the project. DETAILED DESCRIPTION

[0022] In order to deepen the understanding and recognition of the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described and introduced in combination with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments, and are not intended to limit the embodiments in any form. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] See also Figure 1-4 The present invention provides a technical solution: a flexible DC bidirectional buck-boost system architecture method, such as Figure 1 As shown, the following steps are included:

[0024] Step 1, control the number of battery modules: the battery modules are connected to each other to form a battery cluster, battery cluster RACK1, ... N, and the + poles are connected in parallel with the + poles, and the - poles are connected in parallel with the - poles to share the DC bus through the output of the main control optimizer, so as to realize the bidirectional flow of energy under boost / buck;

[0025] Step 2, battery cluster system: multiple battery clusters are connected in parallel to form a battery cluster system, which is used to control active balancing between battery clusters and can realize parallel operation of battery clusters with different rated voltages;

[0026] Step 3: Power isolation: Power isolation is performed between clusters in the battery cluster system to solve the "short board effect" between clusters in the battery cluster, greatly improving the actual available capacity of the battery stack.

[0027] In step three, when the DC buses of multiple battery clusters are connected in parallel, the inconsistent SOC and voltage lead to unbalanced charge and discharge capacity, as well as bias current and circulating current, resulting in the short board effect.

[0028] like Figure 2 As shown, the main control box is set inside the battery cluster, and the main control box is composed of input connector B+ / B- terminals, disconnector, fuse, Hall, main positive KM1, main negative KM2, pre-charge KM3 DC contactor, main control optimizer, main positive KM4 DC contactor and output terminals. The B+ / B- connection terminal on the left side of the main control box is connected to the battery pack, and then passes through the disconnector, fuse, Hall, main positive KM1, main negative KM2, pre-charge KM3 DC contactor to the input side of the main control optimizer. The output of the main control optimizer is connected to the output of the main positive KM4 DC contactor to the P+ / P- output terminal, and the output terminal is connected to the DC bus.

[0029] Figure 3As shown in the figure, it is an embodiment of the present invention. There are 5 2000KVA transformers in the power distribution room of a certain industrial park. The load power of each transformer is different. The flexible DC bidirectional buck-boost system architecture is applicable to the master-controlled battery cluster convergence to form a battery stack, which can be flexibly called to avoid waste of energy storage resources. To make the transformer have remaining available capacity, load absorption, battery discharge depth, discharge efficiency and product form, the energy storage system adopts a power cabinet for each transformer, and the energy storage cabinets converge to form a battery stack, and each power cabinet can call all energy storage cabinets to maximize the utilization of transformer capacity and make charging and discharging more flexible.

[0030] Although the embodiments of the present invention have been shown and described, it should be emphasized that the above description is only an introduction and description of the use of the embodiments of the present invention, and does not limit the present invention in any form. For those of ordinary skill in the art, it can be understood that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. A flexible DC bidirectional buck-boost system architecture method, characterized by: The following steps are involved: Step 1: The number of battery modules can be flexibly configured in a single battery cluster: the battery modules are connected to form a battery cluster, battery cluster RACK1, ... N, and the + poles are connected in parallel with the + poles, and the - poles are connected in parallel with the - poles to share the DC bus through the output of the main control optimizer, so as to realize the bidirectional flow of energy under boost / buck; Step 2, battery cluster system: multiple battery clusters are connected in parallel to form a battery cluster system, which is used to control active balancing between battery clusters and can realize parallel operation of battery clusters with different rated voltages; Step 3: Power isolation: Power isolation is performed between clusters in the battery cluster system to solve the "short board effect" between clusters in the battery cluster, greatly improving the actual available capacity of the battery stack.

2. A flexible DC bidirectional buck-boost system architecture method according to claim 1, characterized in that: In the step three, when the DC buses of multiple battery clusters are connected in parallel, the SOC and voltage are inconsistent, resulting in unbalanced charge and discharge capacity, as well as bias current and circulating current, resulting in the short board effect.

3. A flexible DC bidirectional buck-boost system architecture method according to claim 1, characterized in that: A main control box is arranged inside the battery cluster, and the inside of the main control box is connected to the DC bus by input connector B+ / B- terminals, isolating switch, fuse, Hall, main positive KM1, main negative KM2, pre-charge KM3 DC contactor, main control optimizer, main positive KM4 DC contactor and output terminals.

4. A flexible DC bidirectional buck-boost system architecture method according to claim 3, characterized in that: The B+ / B- connection terminal on the left side of the main control box is connected to the battery pack, and passes through the isolating switch, fuse, Hall, main positive KM1, main negative KM2, and pre-charge KM3 DC contactor to the input side of the main control optimizer. The output of the main control optimizer is connected to the output main positive KM4 DC contactor to the P+ / P- output terminal, and the output terminal is connected to the DC bus.

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