Multi-energy hybrid off-grid system with black start function

Abstract

The utility model discloses a multi-energy hybrid off-grid system with a black start function, which belongs to the technical field of energy distribution and comprises an energy storage system, renewable energy generation equipment and a multi-energy management system. A path of voltage flow is led out from the power supply side of a self-protection loop of the energy storage system to serve as a black-start loop of the multi-energy management system, and a fuse FU1, a control switch, a DC-DC power supply module and a DC-AC inverter are connected to the black-start loop in series. The normal starting of the current source is ensured, and the reliability and the stability of the use of the multi-energy hybrid off-grid system are improved; the risk that in an existing off-grid system, due to the dependency relationship between an energy storage system and renewable energy generation equipment, the off-grid system faces power supply interruption when a voltage source loses efficacy is solved.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the energy distribution / energy storage technical field especially relates to a multi -energy mixed connection off -grid system with black start function. BACKGROUND

[0002] The off -grid system is usually composed of the following several main components: energy storage system and renewable energy generation equipment, the energy storage system is the only voltage source in the off -grid system, and the renewable energy generation equipment is the current source of the off -grid system, which specifically contains photovoltaic energy, hydrogen energy, wind energy, water energy and diesel generator.

[0003] In the multi -energy mixed connection off -grid system, although the renewable energy generation equipment including photovoltaic, hydrogen energy and diesel generator can be used as the current source, they cannot independently output power in the absence of voltage source (such as energy storage system). This dependence makes the off -grid system face the risk of power interruption when the voltage source fails. In order to improve the reliability of the system, it is necessary to consider how to realize black start with limited voltage source.

[0004] To this end, the application designs a multi -energy mixed connection off -grid system with black start function. UTILITY MODEL CONTENTS

[0005] The utility model aims at providing a multi -energy mixed connection off -grid system with black start function to solve the problem that the dependence between the energy storage system and the renewable energy generation equipment in the existing off -grid system easily makes the off -grid system face power interruption when the voltage source fails.

[0006] The application provides a multi -energy mixed connection off -grid system with black start function, which comprises an energy storage system, a renewable energy generation equipment and a multi -energy management system, a voltage current is led out from the power side of the self -protection circuit of the energy storage system as the black start circuit of the multi -energy management system, and the black start circuit is serially connected with a fuse FU1, a control switch, a DC-DC power module and a DC-AC inverter.

[0007] As a preferred scheme of the application: the self -protection circuit of the energy storage system contains a fuse FU2, a contactor KM2 and a circuit breaker QF, and the black start circuit is led out from the input end of the contactor KM2.

[0008] As a preferred scheme of the application: the control switch in the black start circuit is any one of manual switch KB, automatic switch or the manual switch KB and automatic switch parallelly connected and constitute the manual-automatic integrated structure.

[0009] As a preferred scheme of the application: when it is an automatic switch, the automatic switch is a contactor KM1.

[0010] As a preferred scheme of the present application: comprising a standby power supply and a static switch STS, one input end of the static switch STS is connected in the black start loop, and the other input end is connected with the standby power supply, thereby forming a parallel two-way power supply circuit, and the static switch STS can be used to switch in the parallel two-way power supply circuit to provide a starting voltage for the multi-energy management system.

[0011] As a preferred scheme of the present application: the multi-energy management system comprises an energy storage battery management module, a judgment module and a control module; the energy storage battery management module is used to monitor the real-time state of charge (SOC) of the energy storage battery in the energy storage system; the judgment module is used to judge whether the current state of charge is within a preset range; and the control module is used to select to start the black start loop according to the judgment result.

[0012] Compared with the prior art, the present application has the following advantages:

[0013] A voltage current is led out from the power supply side of the self-protection circuit of the energy storage system as a black start loop of the multi-energy management system, when the real-time state of charge (SOC) of the energy storage system is lower than a preset value, the self-protection circuit cuts off the output and starts the black start circuit to supply power to the multi-energy management system (the power of the multi-energy management system is very small, and it is a trickle current for the energy storage system, so the limited remaining power can meet the demand), and then the renewable energy generation device is started as a current source by the multi-energy management system to supply power to the load device; it can be seen that the limited remaining power of the energy storage system is used as the starting voltage of the multi-energy management system, which ensures the normal starting of the current source and improves the reliability and stability of the multi-energy hybrid off-grid system; and the dependence relationship between the energy storage system and the renewable energy generation device in the existing off-grid system is solved, so that the off-grid system faces the risk of power supply interruption when the voltage source fails. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 A structure diagram of leading out a voltage current from the power supply side of the self-protection circuit 20 of the energy storage system as a black start loop is provided for the present application.

[0015] Figure 2 A control principle diagram of the black start loop is provided for the present application.

[0016] Figure 3 A control flow diagram of the black start loop is provided for the present application.

[0017] REFERENCE NUMERALS

[0018] 10 is an energy storage battery; 20 is a self-protection circuit; 30 is a multi-energy management system; 31 is an energy storage battery management module; 32 is a judgment module; 33 is a control module; 40 is a standby power supply;

[0019] FU1-FU2 are fuses; KM1-KM2 are contactors; QF is a circuit breaker; STS is a static switch; DC-DC is a DC power supply module; DC-AC is a DC-AC inverter. Detailed Implementation

[0020] The present invention will be further described in detail below with reference to specific embodiments and accompanying drawings. It should be emphasized that the following description is merely exemplary and not intended to limit the scope and application of the present invention.

[0021] This embodiment provides a multi-energy hybrid off-grid system with black-start functionality, including an energy storage system, renewable energy generation equipment, and a multi-energy management system 30. A voltage stream is drawn from the power supply side of the self-protection circuit 20 of the energy storage system as the black-start circuit for the multi-energy management system 30. When the self-protection circuit 20 cuts off the output, this black-start circuit is activated to supply power to the multi-energy management system 30. Since the power of the multi-energy management system 30 is very small, representing a trickle flow for the energy storage system, a limited amount of power is sufficient to meet the demand. A fuse FU1, a control switch, a DC-DC power module, and a DC-AC inverter are connected in series in this black-start circuit. Figure 1 As shown, the control switch is used to control whether the black start circuit is activated. The fuse FU1 is a circuit protection device used to protect the circuit from damage caused by overload and short circuit. The DC-DC power module is a DC power module used to perform voltage conversion and output a stable required voltage. The DC-AC inverter is a DC-AC inverter used to convert DC voltage to AC voltage. The converted voltage supplies power to the control circuits of the energy management system (EMS), battery management system (BMS), and power conversion system (PCS) in the multi-energy management system 30. When these device control circuits are energized, the PCS can be started as a voltage source. After the PCS is started, the photovoltaic, hydrogen energy, and other renewable energy generation devices can be started as current sources.

[0022] Specifically, a voltage current is led out from the power supply side of the self-protection circuit 20 of the energy storage system as the only voltage source in the multi-energy hybrid off-grid system as the black start circuit of the multi-energy management system 30. When the real-time power state (SOC) of the energy storage system is lower than the preset value, the self-protection circuit 20 cuts off the output and starts the black start circuit to supply power to the multi-energy management system 30, and then starts the renewable energy generation device as a current source to supply power to the load device through the multi-energy management system 30. It can be seen that the scheme uses the limited power of the energy storage system as the starting voltage of the multi-energy management system 30, ensures the normal start of the current source, and improves the reliability and stability of the multi-energy hybrid off-grid system. The problem of power supply interruption of the off-grid system when the voltage source fails due to the dependence between the energy storage system and the renewable energy generation device in the existing off-grid system is solved.

[0023] The SOC of the energy storage battery 10 in the traditional energy storage system is generally 5%-95%. When the SOC of the energy storage battery 10 is lower than 5%, the self-protection circuit 20 is automatically cut off. Although the power consumption of the multi-energy management system 30 is small, in order to ensure reliability, the threshold of the self-protection circuit 20 is preferably adjusted to 15%, that is, the SOC of the energy storage battery 10 in the energy storage system is adjusted to 15%-95% for normal operation.

[0024] The self-protection circuit 20 of the energy storage system includes a fuse FU2, a contactor KM2 and a circuit breaker QF. The black start circuit is led out from the input end of the contactor KM2, so as to ensure that the normal use of the black start circuit is not affected after the self-protection circuit 20 is cut off.

[0025] The control switch in the black start circuit is any one of a manual switch KB, an automatic switch or a hand-automatic integrated structure composed of a manual switch KB and an automatic switch in parallel. When it is an automatic switch, the automatic switch is a contactor KM1. In order to improve the flexibility and reliability of use, the control switch is preferably a hand-automatic integrated structure composed of a manual switch KB and an automatic switch in parallel.

[0026] In order to further improve the reliability of black start, a standby power supply 40 and a static switch STS are included. One input end of the static switch STS is connected to the black start circuit, and the other input end is connected to the standby power supply 40 to form a parallel two-way power supply circuit. The static switch STS can be switched in the parallel two-way power supply circuit to provide a starting voltage for the multi-energy management system 30. The switching of the static switch STS can be achieved in 10ms, and the phenomenon of intermittent power supply between devices will not occur. It can be understood that the standby power supply 40 can be a conventional UPS standby power supply 40.

[0027] The multi-energy management system 30 comprises a storage battery management module 31, a judgment module 32 and a control module 33, the storage battery management module 31 is used for monitoring the real-time state of charge (SOC) of the storage battery 10 in the storage system; the judgment module 32 is used for judging whether the current state of charge is in the preset range; the control module 33 is used for selecting to start the black start loop according to the judgment result, and the storage battery management module 31, the judgment module 32 and the control module 33 constitute a closed-loop control loop.

[0028] As shown in Figures 2-3 The control principle and flow chart of the black start loop provided by the embodiment are shown in the figure, specifically, the storage battery management module 31 monitors and obtains the SOC index in the storage battery 10 in real time, the judgment module 32 judges whether the current state of charge SOC is in the range of 2%-15%, if yes, the control module 33 disconnects the contactor KM1 to disconnect the self-protection loop 20, at the same time, the contactor KM2 is closed to connect the black start loop, if not, the SOC index in the storage battery 10 is continuously monitored and obtained; in the embodiment, in order to ensure the normal operation of the black start loop, when the judgment module 32 judges that the current state of charge SOC is less than 2%, the control module 33 is controlled to switch the STS action to the standby power supply 40, further ensuring the safe and reliable operation of the black start circuit.

[0029] It can be seen that the embodiment can ensure the normal start of the current source by adding the black start loop and adopting the above control process, and the reliability and stability of the multi-energy hybrid off-grid system are improved.

[0030] It can be understood that the above control process and threshold setting are all parameter configurations and logical judgments in the automatic control field, and the embodiment only illustrates the specific use of the black start loop in the above manner.

[0031] The above is only an embodiment of the utility model, and the specific structure and characteristics of the scheme are not described in detail. It should be pointed out that for those skilled in the art, without departing from the utility model, some improvements can be made, which should also be regarded as the protection range of the utility model, and these will not affect the effect and practicality of the utility model. The protection range claimed in the application should be subject to the content of the claims, and the specific implementation mode and the like in the specification can be used to explain the content of the claims.

Claims

1. A multi-energy hybrid off-grid system with black-start function, comprising an energy storage system, renewable energy generation equipment, and a multi-energy management system, characterized in that: A voltage stream is drawn from the power supply side of the self-protection circuit of the energy storage system as the black start circuit of the multi-energy management system. A fuse FU1, a control switch, a DC-DC power module and a DC-AC inverter are connected in series on the black start circuit.

2. The multi-energy hybrid off-grid system with black-start function according to claim 1, characterized in that: The self-protection circuit of the energy storage system includes a fuse FU2, a contactor KM2, and a circuit breaker QF. The black start circuit is led out from the input terminal of the contactor KM2.

3. The multi-energy hybrid off-grid system with black-start function according to claim 2, characterized in that: The control switch in the black start circuit is any one of the following: manual switch KB, automatic switch, or a manual-automatic integrated structure consisting of a manual switch KB and an automatic switch connected in parallel.

4. The multi-energy hybrid off-grid system with black-start function according to claim 3, characterized in that: When it is an automatic switch, the automatic switch is contactor KM1.

5. The multi-energy hybrid off-grid system with black-start function according to claim 1, characterized in that: It includes a backup power supply and a static switch (STS). One input terminal of the static switch (STS) is connected to the black start circuit, and the other input terminal is connected to the backup power supply, thus forming two parallel power supply circuits. The static switch (STS) can switch between the two parallel power supply circuits to provide start-up voltage for the multi-energy management system.

6. The multi-energy hybrid off-grid system with black-start function according to claim 5, characterized in that: The multi-energy management system includes an energy storage battery management module, a judgment module, and a control module; the energy storage battery management module is used to monitor the real-time state of charge (SOC) of the energy storage batteries in the energy storage system; the judgment module is used to determine whether the current state of charge is within a preset range; and the control module is used to select to start the black start circuit based on the judgment result.

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