Pulsating bus voltage architecture for high energy consumption production line light storage power system

Abstract

The application provides a pulsating bus voltage architecture of a high-energy-consumption production line light storage power supply system, and relates to the technical field of light storage power supply.The power grid supplies power for high-energy-consumption production line loads via a three-phase transformer and a multi-pulse thyristor, and a bus with pulsating voltage is led out at the output end of the multi-pulse thyristor;the photovoltaic array is connected to the bus through a first DC / DC converter;the first DC / DC converter injects pulsating current in the opposite direction of the voltage pulsation of the bus;the energy storage battery is connected to the bus through a second DC / DC converter, and the second DC / DC converter injects pulsating current in the opposite direction of the voltage pulsation of the bus.The application injects reverse pulsating current when the power supply system of the high-energy-consumption production line loads is connected to the light storage, so that the original AC bus is changed into a bus with voltage pulsation at the connection point, and the light storage power supply is effectively connected to the power supply system of industrial and commercial power supply.

Description

Technical Field

[0001] This invention relates to the field of photovoltaic power storage technology, and more specifically to a pulsating bus voltage architecture for a high-energy-consumption production line photovoltaic power storage system. Background Technology

[0002] In high-energy-consuming industrial production lines such as those for electrolytic copper foil production and MnO2 production, high-power electrolytic power supplies are required. Therefore, the industrial three-phase AC power from the grid needs to be converted into DC power by a three-phase multi-pulse thyristor rectifier circuit to supply the loads involved in electrolysis. Meanwhile, with the development of new energy technologies, photovoltaic power generation and energy storage technologies are increasingly used in industry and commerce. The DC power output from photovoltaic arrays and energy storage batteries needs to be converted back into AC power by an inverter before being connected to the grid to supply power to the loads.

[0003] In existing technical solutions, the design architecture of power systems in industries such as industrial electrolysis for copper foil production and MnO2 production after integration with photovoltaic energy storage is as follows: Figure 1 As shown, the power system adopts an AC bus architecture. The industrial three-phase power from the grid is stepped down by a transformer (such as an adjustable phase-shifting transformer) and rectified by a rectifier (such as a multi-pulse thyristor rectifier) ​​before being supplied to the electrolytic cell for electrolysis. The DC power from both ends of the photovoltaic array is first controlled by a DC-DC converter using MPPT (Maximum Power Point Tracking) to obtain a constant DC voltage. Then, it is converted to AC power by an inverter and connected to the grid via a grid-connected transformer. It can then be rectified to provide energy for the electrolysis reaction, or rectified to provide energy for the energy storage battery, or surplus power can be fed back to the grid. The energy storage battery can receive power from the grid or the photovoltaic array through rectification, or it can transmit the stored energy to the grid through an inverter, or after inversion and rectification, it can supply the stored energy to the electrolytic cell for electrolysis.

[0004] Existing industrial and commercial power supply systems, after being connected to distributed photovoltaic energy storage, adopt a constant DC bus voltage architecture, such as... Figure 2 As shown. However, in power systems for electrolytic copper foil production and MnO2 production, the high electrolytic current required by the high-energy-consuming electrolytic production lines necessitates the use of multi-pulse thyristor rectification technology. However, this technology results in a multi-pulse pulsating characteristic for the bus voltage, which is forcibly clamped by the three-phase grid voltage, preventing the system from adopting a constant DC bus voltage architecture. This creates a technical bottleneck for the integration of photovoltaic and energy storage power sources. The pressing issue is: how to effectively integrate photovoltaic and energy storage power sources into the power system while the bus voltage is clamped into a pulsating state due to multi-pulse thyristor rectification. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a pulsating bus voltage architecture for a high-energy-consumption production line photovoltaic-storage power system, which solves the technical problem that the photovoltaic-storage power system cannot be effectively connected to the power system when the bus voltage is clamped into a pulsating state due to multi-pulse thyristor rectification.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, the present invention provides the following technical solution:

[0009] This invention provides a pulsating bus voltage architecture for a high-energy-consuming production line photovoltaic-storage power system, including a high-energy-consuming production line load, a photovoltaic array, an energy storage battery, a three-phase transformer, a multi-pulse thyristor rectifier, a first DC / DC converter, and a second DC / DC converter;

[0010] Among them, the power grid supplies power to the load of the high-energy-consuming production line through a three-phase transformer and a multi-pulse thyristor, and a bus with pulsating voltage is led out from the output terminal of the multi-pulse thyristor.

[0011] The photovoltaic array is connected to the bus via a first DC / DC converter; the first DC / DC converter injects a pulsating current in the opposite direction to the voltage pulsation of the bus.

[0012] The energy storage battery is connected to the bus via a second DC / DC converter, which injects a pulsating current in the opposite direction to the voltage pulsation of the bus.

[0013] Preferably, the three-phase transformer includes an adjustable phase-shifting transformer.

[0014] Preferably, the multi-pulse thyristor rectifier includes a twelve-pulse thyristor rectifier.

[0015] Preferably, the first DC / DC converter includes a Boost converter.

[0016] Preferably, the second DC / DC converter is a bidirectional converter.

[0017] Preferably, the bidirectional converter includes a fully controlled Boost converter.

[0018] Preferably, the pulsating current injected into the first DC / DC converter i dcR The calculation methods include:

[0019] i dcR = P m (k) / u dc (k)

[0020] in, u dc (k) represents the first DC / DC converter output port voltage sampled at time k. P m (k) represents the maximum expected power value at time k.

[0021] Preferably, the load of the high-energy-consuming production line includes an electrolytic cell.

[0022] Preferably, the electrolytic cell is used for electrolytic production of copper foil or MnO2.

[0023] Preferably, the energy storage battery includes a lithium battery, a fuel cell, or a supercapacitor.

[0024] (III) Beneficial Effects

[0025] This invention provides a pulsating bus voltage architecture for a high-energy-consumption production line photovoltaic-storage power system. Compared with existing technologies, it has the following advantages:

[0026] This invention injects a reverse-pulsating current when connecting a power system with a high-energy-consuming production line load to a photovoltaic (PV) energy storage system. This transforms the original AC bus into a bus with pulsating voltage at the connection point, enabling effective integration of PV and energy storage power into industrial and commercial power systems. Simultaneously, by injecting a reverse-pulsating current, the original bus requiring a constant DC voltage can be transformed into a bus with pulsating voltage at the connection point. This solution successfully overcomes the technical limitation that PV and energy storage power can only be connected to a constant DC bus, thereby eliminating the need for grid-connected transformers, inverters, and AC transmission lines required for photovoltaic arrays and energy storage batteries, significantly reducing the overall construction cost of the power system. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 Design architecture diagram for integrating photovoltaic and energy storage into the power systems of existing high-energy-consuming production lines such as industrial electrolytic copper foil production and electrolytic MnO2 production;

[0029] Figure 2 A schematic diagram of a constant DC bus voltage architecture for existing industrial and commercial power supply systems after connecting distributed photovoltaic energy storage;

[0030] Figure 3This is a schematic diagram of the pulsating bus voltage architecture of a high-energy-consumption production line photovoltaic-storage power system according to an embodiment of the present invention. Detailed Implementation

[0031] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] This application provides a pulsating bus voltage architecture for a high-energy-consuming production line photovoltaic-storage power system. This solves the technical problem that photovoltaic-storage power supplies cannot be effectively connected to the power system when the bus voltage is clamped into a pulsating state due to multi-pulse thyristor rectification. It enables the injection of reverse pulsating current when the power system of the high-energy-consuming production line load is connected to the photovoltaic-storage system, thereby changing the original AC bus to a bus with a voltage pulsating connection point, breaking through the technical limitation that photovoltaic-storage power supplies can only be connected to a constant DC bus.

[0033] The technical solution in this application is to solve the above-mentioned technical problems, and the general idea is as follows:

[0034] The design architecture of power systems for high-energy-consuming production lines such as industrial electrolytic copper foil production and electrolytic MnO2 production, after being connected to photovoltaic and energy storage, is as follows: Figure 1 As shown. Existing industrial and commercial power supply systems, after being connected to distributed photovoltaic energy storage, adopt a constant DC bus voltage architecture, for example... Figure 2 As shown, the DC bus voltage is stable at 750V.

[0035] The existing technology has the following main drawbacks:

[0036] 1. Adopt Figure 2 In the constant DC bus voltage architecture shown, due to... Figure 1 In the power systems of high-energy-consuming production lines such as electrolytic copper foil production and electrolytic MnO2 production, the bus voltage after rectification by multi-pulse thyristors exhibits multi-pulse pulsation, and this pulsating bus voltage is essentially clamped by the three-phase grid voltage. Therefore, a constant DC bus voltage architecture cannot be adopted. The pressing issue is: how to effectively integrate photovoltaic and energy storage power sources into industrial and commercial power systems, given that the bus voltage is clamped into a pulsating state due to multi-pulse thyristor rectification.

[0037] 2. Existing power systems for high-energy-consuming production lines such as those producing copper foil and MnO2 via photovoltaic (PV) and energy storage systems, after being connected to PV and energy storage, utilize the existing AC bus architecture. The electricity generated by the PV arrays needs to pass through a DC-DC converter (MPPT), inverter, and transformer before being connected to the grid. From the grid, it then undergoes transformation via a phase-shifting adjustable voltage transformer and a multi-pulse thyristor rectifier before reaching the electrolytic cells, the main power load of the factory. Similarly, the electricity generated by the PV arrays also needs to pass through a DC-DC converter (MPPT), inverter, and transformer before being connected to the grid. From the grid, it then undergoes transformation via a transformer and rectifier before being stored in energy storage batteries. The stored energy then needs to be transformed by an inverter and transformer to reach the grid, and from the grid, it undergoes transformation via a phase-shifting adjustable voltage transformer and a multi-pulse thyristor rectifier before reaching the electrolytic cells, the main power load of the factory. In other words, when existing power systems for electrolytic copper foil production and electrolytic MnO2 production are connected to photovoltaic and energy storage systems, the power transmission path between the photovoltaic array, energy storage battery, and electrolytic cell load is too long, and the power undergoes too many transformation stages. The voltage goes through boost and buck stages in sequence, resulting in unnecessary transformations, which leads to increased construction costs, reduced transmission efficiency, and wasted power.

[0038] To address the aforementioned issues, when connecting power systems from high-energy-consuming production lines such as those used for electrolytic copper foil production and MnO2 production to photovoltaic (PV) and energy storage systems, a reverse-pulsating current is injected. This transforms the original AC bus into a bus with pulsating voltage at the connection point, enabling effective integration of PV and energy storage power into industrial and commercial power systems. Furthermore, by injecting a reverse-pulsating current, the bus, which originally required a constant DC voltage connection, can be modified to have a voltage-pulsating connection point. This solution successfully overcomes the technical limitation that PV and energy storage power can only be connected to a constant DC bus, thereby eliminating the need for grid-connected transformers, inverters, and AC transmission lines required for photovoltaic arrays and energy storage batteries, significantly reducing the overall construction cost of the power system.

[0039] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0040] This invention provides a pulsating bus voltage architecture for a high-energy-consumption production line photovoltaic-storage power system, such as... Figure 3 As shown, the pulsating bus voltage architecture includes a high-energy-consuming production line load, a photovoltaic array, an energy storage battery, a three-phase transformer, a multi-pulse thyristor rectifier, a first DC / DC converter, and a second DC / DC converter.

[0041] Among them, the power grid supplies power to the load of the high-energy-consuming production line through a three-phase transformer and a multi-pulse thyristor, and a bus with pulsating voltage is led out from the output terminal of the multi-pulse thyristor.

[0042] The photovoltaic array is connected to the bus via a first DC / DC converter; the first DC / DC converter injects a pulsating current in the opposite direction to the voltage pulsation of the bus.

[0043] The energy storage battery is connected to the bus via a second DC / DC converter, which injects a pulsating current in the opposite direction to the voltage pulsation of the bus.

[0044] It should be noted that, in Figure 3 In the context of high-energy-consuming production lines, electrolytic cells serve as an example. Electrolytic cells can be used to electrolyze copper foil, MnO2, and hydrogen. Other examples of high-energy-consuming production line loads include coal chemical production lines, ceramic production lines, and fertilizer production lines.

[0045] The following is a detailed description of each component in the pulsating bus voltage architecture:

[0046] The three-phase transformer can be an adjustable phase-shifting transformer, and the multi-pulse thyristor rectifier can be a twelve-pulse thyristor rectifier. The first DC / DC converter connected to the photovoltaic array can be a Boost converter that injects reverse pulsating current into the pulsating bus voltage to achieve MPPT and track the pulsating bus voltage. The second DC / DC converter connected to the energy storage battery can be a Boost converter that replaces the traditional Boost diode with a fully controlled switch to inject reverse pulsating current into the pulsating bus voltage to achieve bidirectional flow of energy and track the pulsating bus voltage at the connection point. In specific implementations, the energy storage battery can take various forms such as lithium batteries, fuel cells, and supercapacitors. Furthermore, it should be noted that this pulsating bus voltage architecture is not only applicable to photovoltaic arrays but also suitable for other forms of DC power supplies.

[0047] Meanwhile, the photovoltaic maximum power point tracking strategy for this pulsating bus voltage architecture is as follows:

[0048] High-frequency sampling obtains the photovoltaic array port voltage U pv (k) Port Current I pv (k) Output port voltage of DC / DC converter u dc (k) Output port current i dc (k). Then, the sampled data points are processed using the control frequency of MPPT. U pv (k) and I pv (k) Calculate the average to obtain U pva (k) and I pva (k). After averaging...U pva (k) and I pva (k) Calculate the current output power of the photovoltaic array P pv (k). The current photovoltaic array output power will then be... P pv (k) and the previous time step (k-1) calculated P pv Compare (k-1) and if they are equal, then the maximum expected power value is... P m (k) compared to P m If (k-1) remains constant, then increasing it will affect the expected maximum power value. P m (k) compared to P m (k-1) increase ΔP If it is reduced, the maximum expected power value will be... P m (k) compared to P m (k-1) decreases ΔP ,in ΔP This is the step size for power regulation, a control parameter that can be selected based on actual conditions such as system power and regulation speed. This control parameter can be a constant value or a dynamically changing value. The maximum expected power value at that moment is obtained. P m (k) after, according to i dcR = P m (k) / u dc (k) The reference value for the reverse current that the DC / DC converter needs to inject into the bus can be calculated. i dcR and compared with the actual output port current obtained by high-frequency sampling. i dc (k) Compare to obtain the current error i error (k) can be fed into the output current PI controller to obtain the control duty cycle d of the DC / DC converter as a feedback control quantity, and then the cycle will return to the beginning to perform the next round of sampling and control.

[0049] In summary, compared with existing technologies, it has the following beneficial effects:

[0050] 1. When connecting the power system of a high-energy-consuming production line to the photovoltaic energy storage system, a reverse pulsating current is injected, thereby changing the original AC bus to a bus with voltage pulsation at the connection point, so as to realize the effective connection of the photovoltaic energy storage power supply to the power system of industrial and commercial electricity.

[0051] 2. The electrical energy from photovoltaic arrays and energy storage batteries does not need to go through the original multiple sets of AC transformers, inverters and rectifiers for conversion, and does not go through AC lines for transmission. This reduces the losses in the power conversion and transmission links, improves the efficiency of the power system, and reduces the waste of electrical energy.

[0052] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0053] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A pulsating bus voltage architecture for a high-energy-consumption production line photovoltaic-storage power system, characterized in that, This includes high-energy-consuming production line loads, photovoltaic arrays, energy storage batteries, three-phase transformers, multi-pulse thyristor rectifiers, first DC / DC converters, and second DC / DC converters; Among them, the power grid supplies power to the load of the high-energy-consuming production line through a three-phase transformer and a multi-pulse thyristor, and a bus with pulsating voltage is led out from the output terminal of the multi-pulse thyristor. The photovoltaic array is connected to the bus via a first DC / DC converter; the first DC / DC converter injects a pulsating current in the opposite direction to the voltage pulsation of the bus. The energy storage battery is connected to the bus via a second DC / DC converter, and the second DC / DC converter injects a pulsating current that is opposite to the voltage pulsation direction of the bus. When the power system is connected to the photovoltaic storage, by injecting a pulsating current that is opposite to the voltage pulsation direction of the bus into the first DC / DC converter and the second DC / DC converter, the bus that originally needed to be connected to a constant DC voltage is transformed into a bus with voltage pulsation characteristics at the connection point. Pulsating current injected into the first DC / DC converter i dcR The calculation methods include: i dcR = P m (k) / u dc (k) in, u dc (k) represents the first DC / DC converter output port voltage sampled at time k. P m (k) represents the maximum expected power at time k.

2. The pulsating bus voltage architecture of the high-energy-consumption production line photovoltaic-storage power system as described in claim 1, characterized in that, The three-phase transformer includes an adjustable phase-shifting transformer.

3. The pulsating bus voltage architecture of the high-energy-consuming production line photovoltaic-storage power system as described in claim 1, characterized in that, The multi-pulse thyristor rectifier includes a twelve-pulse thyristor rectifier.

4. The pulsating bus voltage architecture of the high-energy-consumption production line photovoltaic-storage power system as described in claim 1, characterized in that, The first DC / DC converter includes a Boost converter.

5. The pulsating bus voltage architecture of the high-energy-consuming production line photovoltaic-storage power system as described in claim 1, characterized in that, The second DC / DC converter is a bidirectional converter.

6. The pulsating bus voltage architecture of the high-energy-consuming production line photovoltaic-storage power system as described in claim 5, characterized in that, The bidirectional converter includes a fully controlled Boost converter.

7. The pulsating bus voltage architecture of the high-energy-consuming production line photovoltaic-storage power system as described in any one of claims 1 to 6, characterized in that, The high-energy-consuming production line load includes an electrolytic cell.

8. The pulsating bus voltage architecture of the high-energy-consuming production line photovoltaic-storage power system as described in claim 7, characterized in that, The electrolytic cell is used to electrolyze copper foil or to electrolyze MnO2.

9. The pulsating bus voltage architecture of the high-energy-consuming production line photovoltaic-storage power system as described in any one of claims 1 to 6, characterized in that, The energy storage battery includes a lithium battery, a fuel cell, or a supercapacitor.

Images