An off-grid island micro-grid controller power supply system and method

Abstract

The application discloses an off-grid island micro-grid controller power supply system and method, which comprises an uninterruptible power supply device and a dual power automatic switching device. One end of the uninterruptible power supply device is connected with a DC input bus and an AC bus respectively. The AC bus is externally connected with an input power supply. The uninterruptible power supply device is connected with the dual power automatic switching device. The dual power automatic switching device is externally connected with a micro-grid controller. The uninterruptible power supply device is used for providing high-quality and reliable AC power supply. The dual power automatic switching device is used for realizing automatic switching of two power supplies. When the uninterruptible power supply device is faulty and the 400V AC bus of the micro-grid is electrified, the dual power switching device can automatically switch to a standby power input loop, so that the micro-grid controller continues to obtain power input, thereby improving the power supply reliability of the whole micro-grid.

Description

Technical Field

[0001] This invention relates to an off-grid island microgrid controller power supply system and method, belonging to the field of microgrid technology. Background Technology

[0002] With the continuous promotion of new energy technologies, many islands far from the mainland that cannot rely on AC mains power are now receiving electricity from these new energy sources. This new energy power input and load output are coordinated and controlled by a microgrid controller to form a microgrid. In existing microgrids, the microgrid controller is powered by an uninterruptible power supply (UPS). However, in actual operation, due to severe corrosion on islands, the failure rate of UPS devices is particularly high, leading to power loss in the microgrid controller and the collapse of the entire microgrid. Summary of the Invention

[0003] The purpose of this invention is to overcome the technical defects of the existing technology, solve the above-mentioned technical problems, and propose an off-grid island microgrid controller power supply system and method. Taking advantage of the relatively constant voltage of the microgrid itself (except for the black start time) and the fact that the dual power supply switching device has few electrical secondary components and is not easily damaged, the power supply circuit of the microgrid controller is optimized.

[0004] The present invention specifically adopts the following technical solution: an off-grid island microgrid controller power supply system, comprising an uninterruptible power supply (UPS) device and a dual-power automatic switching device. One end of the UPS device is connected to a DC input bus and an AC bus, respectively. The AC bus is connected to an external input power source. The UPS device is connected to the dual-power automatic switching device, which is externally connected to the microgrid controller. The UPS device is used to provide high-quality and reliable AC power, and the dual-power automatic switching device is used to realize automatic switching between the two power sources.

[0005] In a preferred embodiment, the input power source includes any one or more of the following: a wind turbine; a photovoltaic system; a diesel generator; or an energy storage system.

[0006] In a preferred embodiment, the uninterruptible power supply device includes a maintenance bypass circuit breaker, a bypass input circuit breaker, a mains input circuit breaker, a DC input circuit breaker, a first isolation transformer, a rectifier, an inverter, a second isolation transformer, a static switch module, a reverse blocking diode, and an AC output circuit breaker.

[0007] The two ends of the maintenance bypass circuit breaker are respectively connected to the AC bus and the dual power supply automatic transfer device. The two ends of the bypass input circuit breaker are respectively connected to the AC bus and the static switch module. One end of the mains input circuit breaker is connected to the AC bus, and the other end of the mains input circuit breaker is sequentially connected to the first isolation transformer, the rectifier, the inverter, the second isolation transformer, and the static switch module. One end of the DC input circuit breaker is connected to the DC input bus, and the other end of the DC input circuit breaker is connected to the reverse-blocking diode and then to the inverter and the rectifier. The two ends of the AC output circuit breaker are respectively connected to the static switch module and the dual power supply automatic transfer device.

[0008] In a preferred embodiment, the dual-power automatic transfer switch includes a main power supply terminal, a backup power supply terminal, and an AC output terminal. The main power supply terminal of the dual-power automatic transfer switch is connected to the AC output circuit breaker, the backup power supply terminal of the dual-power automatic transfer switch is connected to the maintenance bypass circuit breaker, and the AC output terminal of the dual-power automatic transfer switch is connected to the microgrid controller.

[0009] In a preferred embodiment, when the mains input circuit breaker of the uninterruptible power supply (UPS) is closed, mains power is supplied sequentially through the first isolation transformer, the rectifier, the inverter, the second isolation transformer, and the static switch module. Then, the AC output circuit breaker closes and supplies power to the microgrid controller via the dual power switching device. When a fault occurs in the circuit containing the mains input circuit breaker, the bypass input circuit breaker closes, and mains power is supplied sequentially through the static switch module. Then, the AC output circuit breaker closes and supplies power to the microgrid controller via the dual power switching device. When a fault occurs in the circuit where the bypass input circuit breaker is located, the DC input circuit breaker closes, receiving the mains power from the DC input bus. The power is then supplied sequentially through the reverse stop diode, the inverter, the second isolation transformer, and the static switch module. Finally, the AC output circuit breaker closes and supplies power to the microgrid controller through the dual power supply switching device. If the uninterruptible power supply device fails, the dual power supply switching device switches to the backup power circuit, the maintenance bypass circuit breaker closes, and the mains power directly supplies power to the microgrid controller through the backup power terminal of the dual power supply switching device.

[0010] This invention also proposes a power supply method for an off-grid island microgrid controller, comprising the following steps:

[0011] Step SS1: The mains input circuit breaker of the uninterruptible power supply is closed, and the mains power of the input power supply is supplied in sequence through the first isolation transformer, rectifier, inverter, second isolation transformer and static switch module, and then the AC output circuit breaker is closed to supply power to the microgrid controller through the dual power supply switching device.

[0012] Step SS2: When a fault occurs in the circuit where the mains input circuit breaker is located, the bypass input circuit breaker closes, and the mains power supply is supplied sequentially through the static switch module, and then the AC output circuit breaker closes to supply power to the microgrid controller through the dual power supply switching device.

[0013] Step SS3: When a fault occurs in the circuit where the bypass input circuit breaker is located, the DC input circuit breaker closes to receive the mains power from the DC input bus. The power is then supplied sequentially through the reverse stop diode, inverter, second isolation transformer, and static switch module. Finally, the AC output circuit breaker closes to supply power to the microgrid controller through the dual power supply switching device.

[0014] Step SS4: If the uninterruptible power supply fails, the dual power switching device switches to the backup power circuit, the maintenance bypass circuit breaker closes, and the mains power input directly supplies power to the microgrid controller through the backup power terminal of the dual power switching device.

[0015] As a preferred embodiment, the method for the uninterruptible power supply device to output mains power is as follows: firstly, the power obtained through the mains input circuit breaker circuit is used; secondly, the power obtained through the bypass input circuit breaker circuit is used; and finally, the power obtained through the DC input circuit breaker circuit is used.

[0016] In a preferred embodiment, the dual-power automatic transfer switch includes a main power supply terminal, a backup power supply terminal, and an AC output terminal. The main power supply terminal of the dual-power automatic transfer switch is connected to the AC output circuit breaker, the backup power supply terminal of the dual-power automatic transfer switch is connected to the maintenance bypass circuit breaker, and the AC output terminal of the dual-power automatic transfer switch is connected to the microgrid controller.

[0017] In a preferred embodiment, the dual power supply switching device uses the power from the main power supply for output when both the main power supply and the backup power supply are powered on; only when the main power supply is powered off does it use the power from the backup power input interface for output.

[0018] In a preferred embodiment, the uninterruptible power supply is used to provide high-quality and reliable AC power, and the dual power automatic switching device is used to realize automatic switching between the two power sources.

[0019] The beneficial effects achieved by this invention are as follows: This invention addresses the technical need to solve the problem of high failure rates of uninterruptible power supply (UPS) devices due to severe corrosion on islands, which leads to power loss in the microgrid controller and subsequent collapse of the entire microgrid. The invention utilizes a UPS device equipped with a mains input circuit breaker, a bypass input circuit breaker, a DC input circuit breaker, a maintenance bypass circuit breaker, and an AC output circuit breaker. The AC output circuit breaker of the UPS is connected to the main power supply terminal of a dual-power switching device, while the maintenance bypass circuit breaker is connected to the backup power supply terminal. The dual-power switching device prioritizes the power source from the main power supply terminal, only using the backup power supply terminal when the main power supply terminal is unavailable. When the main power supply terminal's power is restored, it automatically switches back to the mains input. When the UPS fails and the microgrid's 400V AC bus is energized, the dual-power switching device automatically switches to the backup power input circuit, ensuring the microgrid controller continues to receive power, thereby improving the overall power supply reliability of the microgrid. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the principle topology of an off-grid island microgrid controller power supply system according to the present invention. Detailed Implementation

[0021] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0022] Example 1: As Figure 1 As shown, this invention proposes an off-grid island microgrid controller power supply system, including an uninterruptible power supply (UPS) device and a dual-power automatic switching device. One end of the UPS device is connected to a DC input bus and an AC bus, respectively. The AC bus is connected to an external input power source. The UPS device is connected to the dual-power automatic switching device, which is externally connected to the microgrid controller. The UPS device is used to provide high-quality and reliable AC power, and the dual-power automatic switching device is used to realize automatic switching between the two power sources.

[0023] Optionally, the input power source includes any one or more of the following: a wind turbine; a photovoltaic system; a diesel generator; or an energy storage system.

[0024] Optionally, the uninterruptible power supply device includes a maintenance bypass circuit breaker, a bypass input circuit breaker, a mains input circuit breaker, a DC input circuit breaker, a first isolation transformer, a rectifier, an inverter, a second isolation transformer, a static switch module, a reverse blocking diode, and an AC output circuit breaker.

[0025] The two ends of the maintenance bypass circuit breaker are respectively connected to the AC bus and the dual power supply automatic transfer device. The two ends of the bypass input circuit breaker are respectively connected to the AC bus and the static switch module. One end of the mains input circuit breaker is connected to the AC bus, and the other end of the mains input circuit breaker is sequentially connected to the first isolation transformer, the rectifier, the inverter, the second isolation transformer, and the static switch module. One end of the DC input circuit breaker is connected to the DC input bus, and the other end of the DC input circuit breaker is connected to the reverse-blocking diode and then to the inverter and the rectifier. The two ends of the AC output circuit breaker are respectively connected to the static switch module and the dual power supply automatic transfer device.

[0026] Optionally, the dual-power automatic transfer switch includes a main power supply terminal, a backup power supply terminal, and an AC output terminal. The main power supply terminal of the dual-power automatic transfer switch is connected to the AC output circuit breaker, the backup power supply terminal of the dual-power automatic transfer switch is connected to the maintenance bypass circuit breaker, and the AC output terminal of the dual-power automatic transfer switch is connected to the microgrid controller.

[0027] Optionally, when the mains input circuit breaker of the uninterruptible power supply (UPS) is closed, mains power is supplied sequentially through the first isolation transformer, the rectifier, the inverter, the second isolation transformer, and the static switch module, and then the AC output circuit breaker closes to supply power to the microgrid controller via the dual power switching device; when a fault occurs in the circuit where the mains input circuit breaker is located, the bypass input circuit breaker closes, and mains power is supplied sequentially through the static switch module, and then the AC output circuit breaker closes to supply power to the microgrid controller via the dual power switching device; when the... When a fault occurs in the circuit where the bypass input circuit breaker is located, the DC input circuit breaker closes, receiving the mains power from the DC input bus. The power is then supplied sequentially through the reverse stop diode, the inverter, the second isolation transformer, and the static switch module. Finally, the AC output circuit breaker closes and supplies power to the microgrid controller through the dual power supply switching device. If the uninterruptible power supply device fails, the dual power supply switching device switches to the backup power circuit, the maintenance bypass circuit breaker closes, and the mains power directly supplies power to the microgrid controller through the backup power terminal of the dual power supply switching device.

[0028] Example 2: The present invention also proposes a power supply method for an off-grid island microgrid controller, comprising the following steps:

[0029] Step SS1: The mains input circuit breaker of the uninterruptible power supply is closed, and the mains power of the input power supply is supplied in sequence through the first isolation transformer, rectifier, inverter, second isolation transformer and static switch module, and then the AC output circuit breaker is closed to supply power to the microgrid controller through the dual power supply switching device.

[0030] Step SS2: When a fault occurs in the circuit where the mains input circuit breaker is located, the bypass input circuit breaker closes, and the mains power supply is supplied sequentially through the static switch module, and then the AC output circuit breaker closes to supply power to the microgrid controller through the dual power supply switching device.

[0031] Step SS3: When a fault occurs in the circuit where the bypass input circuit breaker is located, the DC input circuit breaker closes to receive the mains power from the DC input bus. The power is then supplied sequentially through the reverse stop diode, inverter, second isolation transformer, and static switch module. Finally, the AC output circuit breaker closes to supply power to the microgrid controller through the dual power supply switching device.

[0032] Step SS4: If the uninterruptible power supply fails, the dual power switching device switches to the backup power circuit, the maintenance bypass circuit breaker closes, and the mains power input directly supplies power to the microgrid controller through the backup power terminal of the dual power switching device.

[0033] Optionally, the uninterruptible power supply (UPS) outputs mains power in the following ways: firstly, it obtains power from the circuit where the mains input circuit breaker is located; secondly, it obtains power from the circuit where the bypass input circuit breaker is located; and finally, it obtains power from the circuit where the DC input circuit breaker is located.

[0034] Optionally, the dual-power automatic transfer switch includes a main power supply terminal, a backup power supply terminal, and an AC output terminal. The main power supply terminal of the dual-power automatic transfer switch is connected to the AC output circuit breaker, the backup power supply terminal of the dual-power automatic transfer switch is connected to the maintenance bypass circuit breaker, and the AC output terminal of the dual-power automatic transfer switch is connected to the microgrid controller.

[0035] Optionally, the dual power supply switching device uses the power from the main power supply for output when both the main power supply and the backup power supply are powered; it only uses the power from the backup power supply input interface for output when the main power supply is powered off.

[0036] Optionally, the uninterruptible power supply is used to provide high-quality and reliable AC power, and the dual power automatic switching device is used to realize automatic switching between the two power sources.

[0037] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An off-grid island microgrid controller power supply system, characterized in that, The system includes an uninterruptible power supply (UPS) and a dual-power automatic transfer switch. One end of the UPS is connected to a DC input bus and an AC bus, respectively. The AC bus is connected to an external power input. The UPS is connected to the dual-power automatic transfer switch, which is externally connected to a microgrid controller. The UPS provides high-quality and reliable AC power, and the dual-power automatic transfer switch enables automatic switching between the two power sources. The uninterruptible power supply device includes a maintenance bypass circuit breaker, a bypass input circuit breaker, a mains input circuit breaker, a DC input circuit breaker, a first isolation transformer, a rectifier, an inverter, a second isolation transformer, a static switch module, a reverse blocking diode, and an AC output circuit breaker. The maintenance bypass circuit breaker is connected to the AC bus and the dual power supply automatic transfer device at both ends, respectively. The bypass input circuit breaker is connected to the AC bus and the static switch module at both ends, respectively. One end of the mains input circuit breaker is connected to the AC bus, and the other end of the mains input circuit breaker is connected in sequence to the first isolation transformer, the rectifier, the inverter, the second isolation transformer, and the static switch module. One end of the DC input circuit breaker is connected to the DC input bus, and the other end of the DC input circuit breaker is connected to the reverse-blocking diode and then to the inverter and the rectifier, respectively. The AC output circuit breaker is connected to the static switch module and the dual power supply automatic transfer device at both ends, respectively. The dual-power automatic switching device includes a main power supply terminal, a backup power supply terminal, and an AC output terminal. The main power supply terminal of the dual-power automatic switching device is connected to the AC output circuit breaker, the backup power supply terminal of the dual-power automatic switching device is connected to the maintenance bypass circuit breaker, and the AC output terminal of the dual-power automatic switching device is connected to the microgrid controller.

2. The off-grid island microgrid controller power supply system according to claim 1, characterized in that, The input power source includes any one or more of the following: a wind turbine; a photovoltaic system; a diesel generator; or an energy storage system.

3. The off-grid island microgrid controller power supply system according to claim 1, characterized in that, When the mains input circuit breaker of the uninterruptible power supply (UPS) is closed, mains power is supplied sequentially through the first isolation transformer, the rectifier, the inverter, the second isolation transformer, and the static switch module. Then, the AC output circuit breaker closes and supplies power to the microgrid controller via the dual-power automatic transfer switch. When a fault occurs in the circuit containing the mains input circuit breaker, the bypass input circuit breaker closes, and mains power is supplied sequentially through the static switch module. Then, the AC output circuit breaker closes and supplies power to the microgrid controller via the dual-power automatic transfer switch. When the bypass input circuit breaker closes, the mains power is supplied sequentially through the static switch module. Finally, the AC output circuit breaker closes and supplies power to the microgrid controller via the dual-power automatic transfer switch. When a fault occurs in the circuit where the circuit breaker is located, the DC input circuit breaker closes, receiving the mains power from the DC input bus. The power is then supplied sequentially through the reverse stop diode, the inverter, the second isolation transformer, and the static switch module. Finally, the AC output circuit breaker closes and supplies power to the microgrid controller through the dual power automatic transfer switch. If the uninterruptible power supply (UPS) fails, the dual power automatic transfer switch connects the backup power circuit, the maintenance bypass circuit breaker closes, and the mains power directly supplies power to the microgrid controller through the backup power terminal of the dual power automatic transfer switch.

4. A power supply method for an off-grid island microgrid controller, characterized in that, Includes the following steps: Step SS1: The mains input circuit breaker of the uninterruptible power supply is closed, and the mains power of the input power supply is supplied sequentially through the first isolation transformer, rectifier, inverter, second isolation transformer, and static switch module. Then, the AC output circuit breaker is closed and the power is supplied to the microgrid controller through the dual power automatic switching device. Step SS2: When a fault occurs in the circuit where the mains input circuit breaker is located, the bypass input circuit breaker closes, and the mains power supply is supplied sequentially through the static switch module, and then the AC output circuit breaker closes to supply power to the microgrid controller through the dual power automatic switching device. Step SS3: When a fault occurs in the circuit where the bypass input circuit breaker is located, the DC input circuit breaker closes to receive the mains power from the DC input bus. The power is then supplied sequentially through the reverse stop diode, inverter, second isolation transformer, and static switch module. Finally, the AC output circuit breaker closes to supply power to the microgrid controller through the dual power automatic switching device. Step SS4: If the uninterruptible power supply device fails, the dual power automatic transfer device switches to the backup power circuit, the maintenance bypass circuit breaker closes, and the mains power of the input power supply is directly supplied to the microgrid controller through the backup power terminal of the dual power automatic transfer device. When the uninterruptible power supply (UPS) outputs mains power, it prioritizes the power obtained from the circuit where the mains input circuit breaker is located, then the power obtained from the circuit where the bypass input circuit breaker is located, and finally the power obtained from the circuit where the DC input circuit breaker is located. The dual-power automatic switching device selects the power from the main power supply for output when both the main power supply and the backup power supply are powered; it only selects the power from the backup power supply for output when the main power supply fails.

5. The power supply method for an off-grid island microgrid controller according to claim 4, characterized in that, The dual-power automatic transfer switch includes a main power supply terminal, a backup power supply terminal, and an AC output terminal. The main power supply terminal of the dual-power automatic transfer switch is connected to the AC output circuit breaker, the backup power supply terminal of the dual-power automatic transfer switch is connected to the maintenance bypass circuit breaker, and the AC output terminal of the dual-power automatic transfer switch is connected to the microgrid controller.

6. The power supply method for an off-grid island microgrid controller according to claim 4, characterized in that, The uninterruptible power supply device is used to provide high-quality and reliable AC power, and the dual power automatic switching device is used to realize automatic switching between the two power sources.

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