A dual power seamless transfer system based on dual-cell energy storage converters

Abstract

The present application belongs to the technical field of multi-power supply system application, and particularly relates to a double-power seamless conversion system based on double-unit energy storage converter. The energy storage converter unit system has the ability to adjust voltage, frequency and phase within its own power support range, has the ability to track the voltage, frequency and phase of the grid power supply and keep consistent with the grid power supply when operating in parallel with the grid, and still can uninterruptedly operate and supply power when the grid power supply fails and the energy storage converter unit system operates in parallel with the voltage source mode. The double-unit energy storage converter controlled reorganization flexible system structure is adopted, the system structure change is realized through the control of the controlled power switch, the function structure of the multi-power seamless switching AC / DC / AC and the power supply power supply energy storage converter voltage source parallel operation high efficient uninterrupted power supply function structure are solved, and the controlled switching seamless conversion is realized when the grid power supply fails and is repaired to restore power supply or the standby power supply is connected to supply power.

Description

Technical Field

[0001] This invention belongs to the field of multi-power system application technology, specifically relating to a seamless dual-power conversion system based on a dual-unit energy storage converter. Background Technology

[0002] When two or more power sources supply power to a load, it is usually one power source and one backup, or one power source and multiple backups. When the power supply fails and stops supplying power, another backup power source is put into operation after the power supply is disconnected, resulting in a seamless power supply switching process. More and more load devices require seamless switching between multiple power sources. Especially in application scenarios requiring dual power supply and in grid-connected / off-grid microgrid systems, there is an urgent need to achieve seamless switching between multiple power sources. The well-known UPS uninterruptible power supply system is one of the existing technical solutions. However, the existing UPS uninterruptible power supply system has obvious defects, such as: the power supply always involves AC to DC and DC to AC conversion, resulting in a lot of power loss; the power conversion is carried out by fast electronic switches, which requires a conversion time of several milliseconds to tens of milliseconds, and cannot meet the requirements of equipment that require high-quality power supply.

[0003] It is well known in the industry that energy storage converter unit systems have the ability to regulate voltage, frequency, and phase within their own power support range. When operating in grid-connected mode, they have the ability to track the voltage, frequency, and phase of the grid power supply and maintain consistency with the grid power supply. When operating in grid-connected mode in voltage source mode, energy storage converter unit systems can still operate and supply power without interruption when encountering grid power failures. However, when the faulty grid power supply is restored or another backup power supply is connected and supplies power, the voltage, frequency, and phase are often inconsistent with the current voltage, frequency, and phase of the energy storage converter unit system that is currently supplying power, which will cause the connection and power supply system to fail. Summary of the Invention

[0004] To address the technical challenge of seamless dual-power conversion, this invention proposes a seamless dual-power conversion system based on a dual-unit energy storage converter, comprising: a main power supply, a system control unit, a first energy storage converter module, a first energy storage battery unit, a second energy storage converter module, a second energy storage battery unit, an electrical load, a backup power supply, a main power supply switch, a power line switch between the first and second energy storage converter modules, an electrical load power switch, a backup power supply power switch, a DC bus switch between the first and second energy storage battery units, a power supply line, a DC bus between the first and second energy storage battery units, a DC power line between the first and second energy storage battery units, a DC power line between the first and second energy storage battery units, an AC power line between the first and second energy storage converter modules, an AC power line between the second and third energy storage converter modules, a system bus, an electrical load power line, and a backup power supply power line.

[0005] The main power supply is connected to the power supply line and is connected to the load power line through the main power supply switch, the power supply line switch between the first and second energy storage converter modules, and the load power line is connected to the load through the load power switch, thus forming a power path in which the main power supply directly supplies power to the load.

[0006] The backup power supply is connected to the backup power supply line and the backup power supply line is connected to the power supply line through the backup power supply power switch. It is then connected to the load power line through the power supply line switch between the first and second energy storage converter modules. The load power line is then connected to the load through the load power switch, thus forming a power path where the backup power supply directly supplies power to the load.

[0007] The main power supply is connected to the power supply line and sequentially connects to the first energy storage converter module via the main power supply switch and the AC power line of the first energy storage converter module. From the first energy storage converter module, it sequentially connects to the DC power line of the first energy storage battery unit, the DC bus between the first and second energy storage battery units, the DC bus switch between the first and second energy storage battery units, and the DC power line of the second energy storage battery unit to the second energy storage converter module. Then, the second energy storage converter module sequentially connects to the AC power line of the second energy storage converter module, the power supply line, the load power line, and the load power line to the load through the load power switch, forming a power path in which the main power supply provides seamless and uninterrupted power to the load.

[0008] The backup power supply is connected to the backup power supply line and the backup power supply line through the backup power supply power switch. The backup power supply line is connected to the power supply line and the power supply line through the AC power line of the first energy storage converter module. The backup power supply line is connected to the first energy storage converter module. The backup power supply line is connected to the second energy storage converter module through the DC power line of the first energy storage battery unit, the DC bus between the first and second energy storage battery units, the DC bus switch between the first and second energy storage battery units, and the DC power line of the second energy storage battery unit. The backup power supply line is connected to the second energy storage converter module through the AC power line of the second energy storage converter module, the power supply line, the load power line, and the load power line through the load power switch. This forms a power path for the backup power supply to seamlessly switch and provide uninterrupted power to the load.

[0009] The first energy storage battery unit is connected to the first energy storage converter module via the DC power line of the first energy storage battery unit. The first energy storage converter module is sequentially connected to the AC power line of the first energy storage converter module, the power supply power line, the power supply power line switch between the first and second energy storage converter modules, the power line of the electrical load, and the power line of the electrical load is connected to the electrical load through the power switch of the electrical load, thus forming a power path in which the first energy storage battery unit provides uninterrupted power supply to the electrical load.

[0010] The second energy storage battery unit is connected to the second energy storage converter module via the DC power line of the second energy storage battery unit. The second energy storage converter module is sequentially connected to the AC power line of the second energy storage converter module, the power supply power line, the power supply power line switch between the first and second energy storage converter modules, the power line of the electrical load, and the power line of the electrical load is connected to the electrical load through the power switch of the electrical load, thus forming a power path for the second energy storage battery unit to provide uninterrupted power supply to the electrical load.

[0011] The system control unit is connected to the first energy storage converter module, the first energy storage battery unit, the second energy storage converter module, the second energy storage battery unit, the backup power supply, the main power supply switch, the power line switch between the first and second energy storage converter modules, the power load switch, the backup power supply switch, and the DC bus switch between the first and second energy storage battery units via the system bus, forming a control link for a dual-power seamless conversion system based on a dual-unit energy storage converter;

[0012] The control operation mode of the dual-power seamless conversion system based on a dual-unit energy storage converter is as follows:

[0013] When the main power supply is supplying power normally, the system control unit controls the main power supply switch, the power line switch between the first and second energy storage converter modules, and the power load switch to close, and controls the backup power supply switch and the DC bus switch between the first and second energy storage battery units to open, and controls the first energy storage converter module and the second energy storage converter module, at least the second energy storage converter module, to operate in voltage source mode;

[0014] When the main power supply fails and stops supplying power, the second energy storage converter module continues to supply power without interruption. At the same time, the system control unit controls the main power supply switch to open, and the second energy storage converter module continuously supplies power to the electrical load.

[0015] When the main power supply is repaired and has the ability to supply power, the system control unit controls the power line switch between the first and second energy storage converter modules to open, and then controls the main power supply switch to close, thus forming a seamless and uninterrupted main power supply.

[0016] Alternatively, if the main power supply fails while the backup power supply is available, the system control unit will disconnect the power supply line switch between the first and second energy storage converter modules and then close the backup power supply switch, thus enabling seamless backup power supply without interruption.

[0017] The dual-power seamless conversion system based on a dual-unit energy storage converter is characterized in that the power supply line switch between the first and second energy storage converter modules is a normally open controlled power switch.

[0018] A dual-power seamless switching system based on a dual-unit energy storage converter utilizes the voltage, frequency, and phase regulation capabilities of the energy storage converter unit system within its own power support range. During grid-connected operation, it can track the voltage, frequency, and phase of the grid power supply and maintain consistency with it. Furthermore, when operating in voltage source mode, the energy storage converter unit system can continue to operate and supply power uninterruptedly even in the event of a grid power failure. Employing a flexible system structure with controlled reconfiguration of the dual-unit energy storage converter, the system structure is changed by controlling a controlled power switch. This solves the functional structure of seamless AC / DC / AC switching between multiple power sources and the efficient uninterrupted power supply function of directly supplying the voltage source of the energy storage converter for parallel operation. It achieves controlled seamless switching when the grid power supply is restored after a failure or when a backup power source becomes available. Attached Figure Description

[0019] Figure 1 This is a schematic diagram illustrating the structural principle of a seamless dual-power conversion system based on a dual-unit energy storage converter. Detailed Implementation

[0020] As an example, a seamless dual-power conversion system based on a dual-unit energy storage converter is described in conjunction with the accompanying drawings. However, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without inventive effort are within the scope of protection of this invention. The technology and solutions of this invention are not limited to the content given in this example.

[0021] like Figure 1As shown, a dual-power seamless conversion system based on a dual-unit energy storage converter includes: a main power supply (1), a system control unit (2), a first energy storage converter module (3), a first energy storage battery unit (4), a second energy storage converter module (5), a second energy storage battery unit (6), an electrical load (7), a backup power supply (8), a main power supply switch (10), a power line switch (11) between the first and second energy storage converter modules, an electrical load power switch (13), and a backup power supply power switch (14). 4) DC bus switch (15) between the first and second energy storage battery units, power supply line (20), DC bus (21) between the first and second energy storage battery units, DC power line (22) of the first energy storage battery unit, DC power line (23) of the second energy storage battery unit, AC power line (24) of the first energy storage converter module, AC power line (25) of the second energy storage converter module, system bus (26), power load line (27), backup power supply line (28), wherein:

[0022] The main power supply (1) is connected to the power supply line (20) and is connected to the load power line (27) through the main power supply switch (10) and the power supply line switch (11) between the first and second energy storage converter modules. The load power line (27) is connected to the load (7) through the load power switch (13), thus forming a power path in which the main power supply (1) directly supplies power to the load (7).

[0023] The backup power supply (8) is connected to the backup power supply line (28) and the backup power supply line (28) is connected to the power supply line (20) through the backup power supply power switch (14) and then connected to the load power line (27) through the power supply power line switch (11) between the first and second energy storage converter modules. The load power line (27) is then connected to the load (7) through the load power switch (13), thus forming a power path in which the backup power supply (8) directly supplies power to the load (7).

[0024] The main power supply (1) is connected to the power supply line (20) and sequentially passes through the main power supply switch (10) and the AC power line (24) of the first energy storage converter module to connect to the first energy storage converter module (3). From the first energy storage converter module (3), the DC power line (22) of the first energy storage battery unit, the DC bus (21) between the first and second energy storage battery units, the DC bus switch (15) between the first and second energy storage battery units, and the second energy storage battery unit... The DC power line (23) of the battery unit is connected to the second energy storage converter module (5), and then the second energy storage converter module (5) is connected in sequence to the AC power line (25), the power supply power line (20), the power load power line (27), and the power load power line (27) is connected to the power load (7) through the power load power switch (13), forming a power path in which the main power supply (1) seamlessly switches and provides uninterrupted power to the power load (7);

[0025] The backup power supply (8) is connected to the backup power supply line (28). The backup power supply line (28) is connected to the power supply line (20) via the backup power supply switch (14). The power supply line (20) is connected to the first energy storage converter module (3) via the AC power line (24) of the first energy storage converter module. The power supply line (20) is connected to the first energy storage converter module (3) via the DC power line (22) of the first energy storage battery unit, the DC bus (21) between the first and second energy storage battery units, and the first and second energy storage batteries in sequence. The DC bus switch (15) between units and the DC power line (23) of the second energy storage battery unit are connected to the second energy storage converter module (5). The second energy storage converter module (5) is then connected to the AC power line (25), power supply power line (20), and power load power line (27) of the second energy storage converter module in sequence. The power load power line (27) is connected to the power load (7) through the power load power switch (13), forming a power path for the backup power supply (8) to seamlessly switch and uninterruptibly supply power to the power load (7).

[0026] The first energy storage battery unit (4) is connected to the first energy storage converter module (3) through the first energy storage battery unit DC power line (22). The first energy storage converter module (3) is sequentially connected to the first energy storage converter module AC power line (24), power supply power line (20), power supply power line switch (11) between the first and second energy storage converter modules, power load power line (27), and the power load power line (27) is connected to the power load (7) through the power load power switch (13), thus forming a power path for the first energy storage battery unit (4) to provide uninterrupted power supply to the power load (7).

[0027] The second energy storage battery unit (6) is connected to the second energy storage converter module (5) through the DC power line (23) of the second energy storage battery unit. The second energy storage converter module (5) is sequentially connected to the AC power line (25) of the second energy storage converter module, the power supply power line (20), the power supply power line switch (11) between the first and second energy storage converter modules, the power load power line (27), and the power load power line (27) is connected to the power load (7) through the power load power switch (13), thus forming a power path for the second energy storage battery unit (4) to provide uninterrupted power supply to the power load (7).

[0028] The system control unit (2) is connected to the first energy storage converter module (3), the first energy storage battery unit (4), the second energy storage converter module (5), the second energy storage battery unit (6), the backup power supply (8), the main power supply switch (10), the power line switch between the first and second energy storage converter modules (11), the power load switch (13), the backup power supply power switch (14), and the DC bus switch between the first and second energy storage battery units (15) via the system bus (26), thus forming a dual-power seamless conversion system control link based on the dual-unit energy storage converter;

[0029] The control operation mode of the dual-power seamless conversion system based on a dual-unit energy storage converter is as follows:

[0030] When the main power supply (1) is supplying power normally, the system control unit (2) controls the main power supply switch (10), the power line switch (11) between the first and second energy storage converter modules, and the power load switch (13) to close, and controls the backup power supply switch (14) and the DC bus switch (15) between the first and second energy storage battery units to open, and controls the first energy storage converter module (3) and the second energy storage converter module (5), of which at least the second energy storage converter module (5) operates in voltage source mode;

[0031] When the main power supply (1) fails and stops supplying power, the second energy storage converter module (5) continues to supply power and operates continuously. At the same time, the system control unit (2) controls the main power supply switch (10) to open, and the second energy storage converter module (5) continuously supplies power to the electrical load (7).

[0032] When the main power supply (1) is repaired and has the ability to supply power, the system control unit (2) controls the power supply line switch (11) between the first and second energy storage converter modules to disconnect, and then controls the main power supply switch (10) to close, so that the main power supply (1) can be seamlessly put into operation and supply power without interruption.

[0033] Or, if the main power supply (1) fails and the backup power supply (8) has the ability to supply power, the system control unit (2) controls the power supply line switch (11) between the first and second energy storage converter modules to disconnect, and then controls the backup power supply power switch (14) to close, so that the backup power supply (8) can be seamlessly put into operation and supply power without interruption.

[0034] A dual-power seamless switching system based on a dual-unit energy storage converter is characterized in that the power line switch (11) between the first and second energy storage converter modules is a normally open controlled power switch.

[0035] A dual-power seamless switching system based on a dual-unit energy storage converter utilizes the voltage, frequency, and phase regulation capabilities of the energy storage converter unit system within its own power support range. During grid-connected operation, it can track the voltage, frequency, and phase of the grid power supply and maintain consistency with it. Furthermore, when operating in voltage source mode, the energy storage converter unit system can continue to operate and supply power uninterruptedly even in the event of a grid power failure. Employing a flexible system structure with controlled reconfiguration of the dual-unit energy storage converter, the system structure is changed by controlling a controlled power switch. This solves the functional structure of seamless AC / DC / AC switching between multiple power sources and the efficient uninterrupted power supply function of directly supplying the voltage source of the energy storage converter for parallel operation. It achieves controlled seamless switching when the grid power supply is restored after a failure or when a backup power source becomes available.

Claims

1. A dual power seamless transfer system based on dual cell energy storage inverters, comprising: The main power supply, the system control unit, the first energy storage inverter module, the first energy storage battery unit, the second energy storage inverter module, the second energy storage battery unit, the electric load, the standby power supply, the main power supply switch, the power line on-off switch between the first and second energy storage inverter modules, the electric load power switch, the standby power supply power line, the DC bus on-off switch between the first and second energy storage battery units, the power supply power line, the DC bus between the first and second energy storage battery units, the first energy storage battery unit DC power line, the second energy storage battery unit DC power line, the first energy storage inverter module AC power line, the second energy storage inverter module AC power line, the system bus, the electric load power line, and the standby power supply power line, wherein: The main power supply is connected to the power supply power line, and is connected to the electric load power line through the main power supply switch and the power line on-off switch between the first and second energy storage inverter modules, and the electric load power line is connected to the electric load through the electric load power switch, thereby forming a power path in which the main power supply directly supplies power to the electric load; The standby power supply is connected to the standby power supply power line, and is connected to the power supply power line through the standby power supply power line and the standby power supply power switch, and is connected to the electric load power line through the power line on-off switch between the first and second energy storage inverter modules, and the electric load power line is connected to the electric load through the electric load power switch, thereby forming a power path in which the standby power supply directly supplies power to the electric load; The main power supply is connected to the power supply power line, and is connected to the first energy storage inverter module through the main power supply switch and the first energy storage inverter module AC power line, and the first energy storage inverter module is connected to the second energy storage inverter module through the first energy storage battery unit DC power line, the DC bus between the first and second energy storage battery units, the DC bus on-off switch between the first and second energy storage battery units, and the second energy storage battery unit DC power line, and the second energy storage inverter module is connected to the power supply power line through the second energy storage inverter module AC power line, and the power supply power line is connected to the electric load power line, and the electric load power line is connected to the electric load through the electric load power switch, thereby forming a power path in which the main power supply directly supplies power to the electric load without interruption; The standby power supply is connected with the standby power supply power line and the standby power supply power line is connected with the power supply power line through the standby power supply power switch, and the power supply power line is connected with the first energy storage inverter module through the first energy storage inverter module AC power line, and the first energy storage inverter module is sequentially connected with the first energy storage battery unit DC power line, the first and second energy storage battery unit DC bus, the first and second energy storage battery unit DC bus on-off switch, the second energy storage battery unit DC power line and the second energy storage inverter module, and then the second energy storage inverter module is sequentially connected with the second energy storage inverter module AC power line, the power supply power line, the power load power line and the power load through the power load power switch, thereby forming an uninterrupted power supply path for the power load by the standby power supply. The first energy storage battery unit is connected with the first energy storage inverter module through the first energy storage battery unit DC power line, and the first energy storage inverter module is sequentially connected with the first energy storage inverter module AC power line, the power supply power line, the first and second energy storage inverter module power line on-off switch, the power load power line and the power load through the power load power switch, thereby forming an uninterrupted power supply path for the power load by the first energy storage battery unit. The second energy storage battery unit is connected with the second energy storage inverter module through the second energy storage battery unit DC power line, and the second energy storage inverter module is sequentially connected with the second energy storage inverter module AC power line, the power supply power line, the first and second energy storage inverter module power line on-off switch, the power load power line and the power load through the power load power switch, thereby forming an uninterrupted power supply path for the power load by the second energy storage battery unit. The system control unit is connected with the first energy storage inverter module, the first energy storage battery unit, the second energy storage inverter module, the second energy storage battery unit, the standby power supply, the main power supply switch, the first and second energy storage inverter module power line on-off switch, the power load power switch, the standby power supply power switch and the first and second energy storage battery unit DC bus on-off switch through the system bus, thereby forming a double power seamless conversion system control link based on the double-unit energy storage inverter. The control operation mode of the double power seamless conversion system based on the double-unit energy storage inverter is as follows: When the main power supply is normally powered, the system control unit controls the main power supply switch, the first and second energy storage inverter module power line on-off switch and the power load power switch to be closed, controls the standby power supply power switch and the first and second energy storage battery unit DC bus on-off switch to be opened, and controls the first energy storage inverter module and the second energy storage inverter module, at least the second energy storage inverter module, to operate in voltage source mode. When the main power supply fails to stop power supply, the second energy storage converter module operates uninterruptedly, and the system control unit controls the main power supply switch to be turned off, so that the second energy storage converter module uninterruptedly supplies power to the power load; When the main power supply fails to stop power supply, the second energy storage converter module operates uninterruptedly, and the system control unit controls the main power supply switch to be turned off, so that the second energy storage converter module uninterruptedly supplies power to the power load; When the main power supply fails to stop power supply, the second energy storage converter module operates uninterruptedly, and the system control unit controls the main power supply switch to be turned off, so that the second energy storage converter module uninterruptedly supplies power to the power load; 2. The dual power seamless transfer system based on dual cell energy storage inverter according to claim 1, characterized in that The first and second energy storage converter modules are connected in series through the power supply power line switch. The first and second energy storage converter modules are connected in series through the power supply power line switch.

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