TWI532296B - Double-port energy storage system and control method thereof - Google Patents

Description

Dual port energy storage system and control method thereof

The present invention relates to a dual port energy storage system and a control method thereof; and more particularly to an energy storage system with dual AC ports and a control method thereof, which can elastically supply various power qualities and simplify the overall structure.

Figure 1 is a schematic diagram showing the architecture of a conventional energy storage system for storing electrical energy. Referring to FIG. 1 , the conventional energy storage system 1 mainly includes a bidirectional power conversion circuit 11 and an electrical energy storage device 12 . The bidirectional power conversion circuit 11 has an AC side and a DC side. The AC side of the bidirectional power conversion circuit 11 is connected to a mains power supply 10 via an AC switch 14, and the DC side of the bidirectional power conversion circuit 11 is connected to the electric energy storage device 12. The AC side of the bidirectional power conversion circuit 11 is further connected to a load 13.

Referring again to FIG. 1, when the mains power supply 10 is normal, and during the off-peak period of the mains supply 10, the AC switch 14 can be selectively operated to close. In this way, the AC power of the commercial power source 10 is converted into DC power by the bidirectional power conversion circuit 11, and the DC power input is stored in the electric energy storage device 12, as indicated by the broken line and the arrow direction in FIG. The electrical energy storage device 12 includes a plurality of batteries or other DC power sources. When the electrical energy storage device 12 completes charging, the power of the commercial power source 10 is selected to be stopped from being input to the electrical energy storage device 12. Further, the power of the commercial power source 10 is selectively supplied to the load 13, as indicated by a broken line and an arrow direction on the first drawing.

Figure 2 is a schematic diagram showing the architecture of a conventional energy storage system for discharging electrical energy when the utility power is normal, which corresponds to the energy storage system of Figure 1. Referring to FIG. 2, when the mains power supply 10 is normal, and during the peak period of the mains supply 10, the AC switch 14 can be selectively operated to be closed, and the power of the mains supply 10 is supplied to the load 13. , as shown in the dotted line on the second figure and the direction of the arrow. In addition, the conventional energy storage system operates the electrical energy storage device 12 to release its stored electrical energy, that is, the direct current electrical energy of the electrical energy storage device 12 is converted into alternating current electrical energy via the bidirectional power conversion circuit 11 to supply power to the load 13, such as the second The dotted line and the direction of the arrow are shown below to achieve the purpose of storing a portion of the power of the load 13 from the peak to store the power supply.

Figure 3 is a schematic diagram showing the structure of a conventional energy storage system for discharging electrical energy when the utility power is abnormal, which corresponds to the state of the released energy of the energy storage system of Figure 2. Please refer to Figure 3, when the mains power supply 10 When an abnormality or malfunction occurs, the AC switch 14 is selectively operated to be turned "open", that is, the commercial power source 10 is turned off. At this time, the conventional energy storage system Only operating the electrical energy storage device 12 to release its stored electrical energy, The DC power of the electrical energy storage device 12 is converted into AC power via the bidirectional power conversion circuit 11 and supplied to the load 13, as indicated by the dashed line and the direction of the arrow in FIG. 3, that is, the load 13 is completely supplied by the electrical energy storage device 12. Required power.

For example, another conventional energy storage system, such as the patent of US Patent No. 7911187, Energy Storage System, discloses an energy storage system comprising a battery charger and a plurality of energy storage devices. The charger is connected to a DC-AC current source [DC-AC current source], the energy storage device is respectively coupled between the battery charger and a plurality of subsystems. Each of this energy The storage device comprises a magnetic capacitor (MCAP) and an over current protection device (OCPD). The magnetic capacitor is charged by the battery charger, and the magnetic capacitor supplies power to the subsystem, and the subsystem is connected to the magnetic capacitor. The overcurrent protection device detects the current flowing from the magnetic capacitor to one of the subsystems to avoid an overcurrent.

Another conventional energy storage system, such as the patent application of Monitoring Cell in energy storage system, discloses an energy storage system comprising a battery monitoring system, and the energy storage system is connected in series by a plurality of battery cells. composition. The battery monitoring system includes a plurality of monitors that are connected in series to form a chain that includes at least a first monitor and a second monitor. The first monitor is configured to monitor at least one first battery unit of the energy storage system to generate first monitoring data. The second monitor is configured to monitor at least one second battery unit in the energy storage system to generate second monitoring data. The first monitor is configured to transfer the first monitoring data to the second monitor for transmission to a controller.

Another conventional energy storage system, such as the patent management system of the US Patent Publication No. 20110296218, the method of controlling the same, and the energy storage system including the battery management system, discloses an energy storage system including a battery management system. System [BMS], which supplies power in an energy-saving manner to reduce electricity bills.

However, conventional energy storage systems only provide a single AC port function, which does not provide a dual AC port function, so that conventional energy storage systems are limited in use and lack flexibility. Therefore, conventional energy storage systems necessarily have the need to further improve their overall construction and operational control methods. The foregoing patents are only for the purpose of reference to the present invention, and are not intended to limit the scope of the present invention.

In view of the above, the present invention provides a dual port energy storage system and a control method thereof, in order to meet the above technical problems and needs. A dual port energy storage system is provided with a first AC port, a second AC port and a plurality of switches for controlling operation of the plurality of switches, and storing energy stored in the dual port energy storage system via the first AC port and The second AC port outputs a pair of AC ports, and the power quality of the first AC port and the second AC port (eg, voltage, frequency, etc.) is selected not to be affected by the mains or depends on the mains, so the dual port energy storage The system provides different levels of power supply quality via the first AC port and the second AC port. The present invention has the advantage of improving the flexibility of the conventional energy storage system to supply various power qualities. In addition, the dual port energy storage system of the present invention provides dual AC ports to avoid the configuration of two conventional energy storage systems, thereby providing the advantage of a simplified overall configuration.

The main purpose of the preferred embodiment of the present invention is to provide a dual port energy storage system and a control method thereof, which are provided with a first AC port and a second AC port in a dual port energy storage system, and utilize a bidirectional power conversion circuit. And a DC-AC inverter circuit, the stored energy of an electrical energy storage device is formed into a pair of AC ports via the first AC port and the second AC port, so that the commercial power level is provided via the first AC port and the second AC port. Power quality or provide clean and stable power quality to achieve the flexibility to supply a variety of power quality and simplify the overall structure.

In order to achieve the above object, a dual port energy storage system according to a preferred embodiment of the present invention comprises: a bidirectional power conversion circuit having an AC terminal and a DC terminal; a DC-AC inverter circuit having a DC terminal and a DC An AC storage device connected between the DC end of the bidirectional power conversion circuit and the DC end of the DC-AC inverter circuit; a first AC port connected to the DC-AC inverter a second AC port connected between a mains power source or an AC power source and an AC terminal of the bidirectional power conversion circuit; a first switch connected to the mains power source or the AC power source and the two-way a second switch connected between a first connection point formed between the first switch and the AC end of the bidirectional power conversion circuit and the first AC port; a third a switch connected between the mains power source or the AC power source and the second AC port; and a fourth switch connected to a second connection point formed between the second switch and the first AC port and the first Between the two AC ports; wherein when the mains power or the AC power is normal, the first switch and the third switch are selectively closed, and the second switch and the fourth switch are opened, so that the main power or AC power Directly supplying a commercial power level alternating current to the second alternating current port, and operating the two-way power conversion circuit to convert the alternating current power of the mains power source or the alternating current power source into direct current power The storage device is charged, and the DC power of the bidirectional power conversion circuit is converted into a stable AC power supply to the first AC port via the DC-AC inverter circuit; wherein when the commercial power source or the AC power source is normal and the power storage is performed When the device performs discharging, the first switch and the third switch are selected to be kept closed, and the second switch and the fourth switch are maintained to form an open circuit, so that the mains power source or the alternating current power source directly supplies the mains level alternating current to the second An AC port, and the discharge DC power of the electrical energy storage device is converted into the stable AC power to the first AC port via the DC-AC inverter circuit, and the electrical energy storage device is selectively discharged via the bidirectional power conversion circuit Converting DC power into AC power to the mains or AC power; When the mains power source or the AC power source fails or is repaired, the first switch and the third switch maintain an open circuit, and the second switch and the fourth switch maintain a closed state, and are selected to pass through the bidirectional power conversion circuit and the DC The AC inverter circuit converts the discharged DC power of the electrical energy storage device into AC power, and supplies power to the first AC port and the second AC port in parallel.

The bidirectional power conversion circuit of the preferred embodiment of the present invention is selected from the group consisting of a combined circuit or device having a bidirectional power conversion function.

The DC-AC inverter circuit of the preferred embodiment of the present invention is selected from a circuit or device having a DC-AC conversion function.

In the preferred embodiment of the present invention, the first AC port is connected to a first load.

In the preferred embodiment of the present invention, the second AC port is connected to a second load.

In a preferred embodiment of the present invention, when the mains power source or the AC power source fails, the first switch and the third switch maintain an open circuit, and the second switch and the fourth switch maintain a closed state, so the first AC port and the first port The two AC ports are not interrupted by the mains power supply or AC power failure.

In the preferred embodiment of the present invention, when the bidirectional power conversion circuit or the DC-AC inverter circuit fails or is repaired, the first switch and the second switch are used to form a closed state, so that the first AC port is directly powered by the mains power supply. Or an AC power source for supplying power, and the mains power source or the AC power source directly supplies AC power to the second AC port via the third switch.

In order to achieve the above object, a control method of a dual port energy storage system according to a preferred embodiment of the present invention includes: a dual port energy storage system including a bidirectional power conversion circuit, a DC-AC inverter circuit, an electrical energy storage device, and a first An AC port, a second AC port, a first switch, a second switch, and a a third switch, a fourth switch; the bidirectional power conversion circuit has an AC terminal and a DC terminal, and the DC-AC inverter circuit has an AC terminal and a DC terminal, and the electrical energy storage device is connected to the bidirectional power conversion Between the DC terminal of the circuit and the DC terminal of the DC-AC inverter circuit, the first AC port is connected to the AC terminal of the DC-AC inverter circuit, and the second AC port is connected to a mains power source or an AC power source and The first switch is connected between the AC end of the bidirectional power conversion circuit and the AC power source and the AC end of the bidirectional power conversion circuit, and the second switch is connected to the first switch and the bidirectional power conversion circuit a first switch formed between the first end and the first AC port, the third switch is connected between the mains power source or the AC power source and the second AC port, the fourth switch is connected to the a second connection point formed between the second switch and the first AC port and the second AC port; when the mains power or AC power is normal, the first switch is selected The third switch forms a closed state, and forms an open circuit between the second switch and the fourth switch, so that the mains power source or the AC power source directly supplies a commercial power level alternating current to the second AC port, and operates the bidirectional power conversion circuit to operate the mains power source Or AC power of the AC power source is converted into DC power to charge the power storage device, and the DC power of the two-way power conversion circuit is converted into a stable AC power supply to the first AC port via the DC-AC inverter circuit; When the mains power source or the AC power source is normal and the electric energy storage device is discharging, the first switch and the third switch are selected to be kept closed, and the second switch and the fourth switch are maintained to form an open circuit, so that the mains power source or The AC power source directly supplies the commercial power level alternating current to the second AC port, and converts the discharged DC power of the electrical energy storage device into the stable AC power supply to the first AC port via the DC-AC inverter circuit, and selects via The bidirectional power conversion circuit uses the electric energy storage device The discharge DC power is converted into AC power to be supplied to the utility power source or the AC power source; when the utility power source or the AC power source fails or is repaired, the first switch and the third switch maintain an open circuit, and the second switch and the fourth switch The switch is maintained to be closed, and the discharge DC power of the electrical energy storage device is selected to be converted into AC power via the bidirectional power conversion circuit and the DC-AC inverter circuit, and is supplied in parallel to the first AC port and the second AC port.

The bidirectional power conversion circuit of the preferred embodiment of the present invention is selected from the group consisting of a combined circuit or device having a bidirectional power conversion function.

The DC-AC inverter circuit of the preferred embodiment of the present invention is selected from a circuit or device having a DC-AC conversion function.

In the preferred embodiment of the present invention, the first AC port is connected to a first load.

In the preferred embodiment of the present invention, the second AC port is connected to a second load.

In a preferred embodiment of the present invention, when the mains power source or the AC power source fails, the first switch and the third switch maintain an open circuit, and the second switch and the fourth switch maintain a closed state, so the first AC port and the first port The two AC ports are not interrupted by the mains power supply or AC power failure.

In the preferred embodiment of the present invention, when the bidirectional power conversion circuit or the DC-AC inverter circuit fails or is repaired, the first switch and the second switch are used to form a closed state, so that the first AC port is directly powered by the mains power supply. Or an AC power source for supplying power, and the mains power source or the AC power source directly supplies AC power to the second AC port via the third switch.

1‧‧‧ Energy storage system

10‧‧‧mains power supply

11‧‧‧Bidirectional power conversion circuit

12‧‧‧Electric energy storage device

13‧‧‧ load

14‧‧‧AC switch

2‧‧‧Dual Port Energy Storage System

20‧‧‧mains power supply

21‧‧‧Two-way power conversion circuit

22‧‧‧DC-AC inverter circuit

23‧‧‧Electric energy storage device

24‧‧‧First switch

25‧‧‧Second switch

26‧‧‧ Third switch

27‧‧‧fourth switch

28‧‧‧First AC port

29‧‧‧Second AC port

3‧‧‧First load

3'‧‧‧second load

A‧‧‧first connection point

B‧‧‧second connection point

Figure 1: Schematic diagram of the structure of a conventional energy storage system for storing electrical energy Figure.

Figure 2: Schematic diagram of the conventional energy storage system to release electrical energy when the utility power is normal.

Figure 3: Schematic diagram of the structure of the conventional energy storage system for releasing electrical energy when the utility power is abnormal.

Figure 4 is a block diagram showing the architecture of a dual port energy storage system in accordance with a preferred embodiment of the present invention.

Figure 5 is a block diagram showing the architecture of a dual port energy storage system in accordance with a preferred embodiment of the present invention for operating a state of charge of an electrical energy storage device.

Figure 6 is a block diagram showing the architecture of a dual port energy storage system in accordance with a preferred embodiment of the present invention operating in an electrical energy storage device.

Figure 7 is a block diagram showing the architecture of a dual port energy storage system in accordance with a preferred embodiment of the present invention operating in an electrical energy storage device for another discharge state.

In order to fully understand the present invention, the preferred embodiments of the present invention are described in detail below, and are not intended to limit the invention.

The dual port energy storage system and the control method thereof according to the preferred embodiment of the present invention are applicable to various dual port energy storage systems, or even extended to various energy storage systems with multiple ports, such as a residential energy storage system [residential ESS] ], a community-type energy storage system (community ESS) or a commercial energy storage system (commerical ESS), but it is not intended to limit the scope of application of the present invention.

Figure 4 is a block diagram showing the architecture of a dual port energy storage system in accordance with a preferred embodiment of the present invention. Referring to FIG. 4, the dual port energy storage system 2 of the preferred embodiment of the present invention is connected to a mains power source 20 (or an AC power source) for storing the energy input of the utility power source 20 in the dual port energy storage system. 2. Output the stored energy of the dual port energy storage system 2 to the utility power source 20. The preferred embodiment of the present invention uses an alternating current power source to include various new energy sources, such as: too Solar power, wind power, fuel cell or other renewable energy sources. The source of the electrical energy storage device 23 includes various new energy sources such as solar energy, wind energy, fuel cells or other renewable energy sources.

Referring to FIG. 4 again, the dual port energy storage system 2 of the preferred embodiment of the present invention includes a bidirectional power conversion circuit 21, a DC-AC inverter circuit 22, an electrical energy storage device 23, and a first switch 24. a second switch 25, a third switch 26, a fourth switch 27, a first AC port 28 and a second AC port 29. Controlling the operation of the bidirectional power conversion circuit 21, the DC-AC inverter circuit 22, and the electrical energy storage device 23 by using the first switch 24, the second switch 25, the third switch 26, and the fourth switch 27 in a closed or open manner, so that The electric energy storage device 23 performs electric energy storage or stores the electric energy through the first AC port 28 and the second AC port 29 to appropriately output or parallelly output AC electric energy to provide various levels of power supply quality.

Referring to FIG. 4 again, the bidirectional power conversion circuit 21 has an AC terminal (left side) and a DC terminal (right side), and the DC-AC inverter circuit 22 has a DC terminal (left side) and an AC terminal. 〔Right〕. The electrical energy storage device 23 is connected between the DC terminal of the bidirectional power conversion circuit 21 and the DC terminal of the DC-AC inverter circuit 22. The bidirectional power conversion circuit 21 can also be selected from a combined circuit or device having a bidirectional power conversion function. In contrast, the DC-AC inverter circuit 22 can also be selected from a circuit or device having a DC-AC conversion function. In addition, the first AC port 28 and the second AC port 29 are appropriately disposed in the dual port energy storage system 2 . The dual port energy storage system 2 is connected to a first load 3 and a second load 3' via the first AC port 28 and the second AC port 29, respectively.

Referring to FIG. 4 again, the first switch 24 is connected to the mains power source 20 or the AC power source and the bidirectional power conversion circuit 21. Between the streams. The first switch 24 is an AC switch, which may be selected from various mechanical devices, such as a relay or a magnetic contactor, or may be selected from various solid-state devices. For example, an anti-parallel thyristor or an insulated gate bipolar transistor (IGBT).

Referring to FIG. 4 again, the second switch 25, the third switch 26, and the fourth switch 27 are an AC switch, which may be selected from various mechanical components, such as relays or electromagnetic contactors, or may be selected from various types. Solid-state components, such as reverse-connected thyristors or isolation gate transistors. The second switch 25 is connected between a first connection point a formed between the first switch 24 and the AC terminal of the bidirectional power conversion circuit 21 and the first AC port 28. The third switch 26 is connected between the mains power source 20 or the AC power source and the second AC port 29. The fourth switch 27 is connected between a second connection point b formed between the second switch 25 and the first AC port 28 and the second AC port 29.

FIG. 5 is a block diagram showing the architecture of a dual port energy storage system in accordance with a preferred embodiment of the present invention for operating a state of charge of an electrical energy storage device, corresponding to the dual port energy storage system 2 of FIG. Referring to FIG. 5, the first operational state of the dual port energy storage system 2 is: when the mains power source 20 or the AC power source is normal, the first switch 24 and the third switch 26 are selected to be closed, and The second switch 25 and the fourth switch 27 are formed as an open circuit, so that the commercial power source 20 or the AC power source directly supplies a commercial power level alternating current to the second AC port 29 [second load 3'], as shown by the dotted line on FIG. And the direction of the arrow is displayed, and the bidirectional power conversion circuit 21 is operated to convert the AC power of the commercial power source or the AC power source into DC power to charge the energy storage device 23, and the DC power exchange device 22 is further used to The DC power of the bidirectional power conversion circuit 21 is converted into a stable AC power supply to the first AC port 28 [first Load 3], as indicated by the dotted line and arrow direction in Figure 5. Therefore, when the commercial power source 20 or the AC power source is normal, the power quality of the second load 3' is determined by the commercial power source 20 or the AC power source. In addition, the power quality of the first load 3 is independent of the mains power source 20 or the AC power source, and is determined by the DC-AC inverter circuit 22, so that interference of the mains power source 20 or the AC power source can be avoided, that is, supplied to the The power quality of the first load 3 is a clean and stable power source. Therefore, the present invention can determine that the load must be selectively connected to the first AC port 28 or the second AC port 29 according to the power quality requirements of the first load 3 and the second load 3'.

FIG. 6 is a block diagram showing the architecture of a dual port energy storage system operating in a state of discharge of an electrical energy storage device according to a preferred embodiment of the present invention, which corresponds to FIG. Referring to FIG. 6, the second operation state of the dual port energy storage system 2 is: when the mains power supply 20 or the AC power supply is normal and the electrical energy storage device 23 discharges, the first switch 24 is selected. The third switch 26 is maintained to form a closed state, and the second switch 25 and the fourth switch 27 are maintained to form an open circuit, so that the commercial power source 20 or the AC power source directly supplies the commercial power level alternating current to the second AC port 29 [the second load 3 '], as indicated by the dashed line and the direction of the arrow in FIG. 6, and the discharged DC power of the electrical energy storage device 23 is converted into the stable AC power to the first AC port 28 via the DC-AC inverter circuit 22. [First load 3], as indicated by the lower right dotted line and the direction of the arrow in FIG. 6, and the discharge DC power of the electrical energy storage device 23 is converted into AC power via the bidirectional power conversion circuit 21 to be supplied to the commercial power supply 20 Or AC power, as shown by the lower left dotted line and the direction of the arrow in Figure 6.

Figure 7 is a block diagram showing the architecture of a dual port energy storage system in accordance with a preferred embodiment of the present invention operating in an electrical energy storage device for another state of discharge, corresponding to Figures 5 and 6. Referring to FIG. 7, the third operational state of the dual port energy storage system 2 is: when the mains power supply 20 or the alternating current power supply is normal and the electrical energy storage device 23 discharges, Selecting the first switch 24 and the third switch 26 to form an open circuit, and forming the second switch 25 and the fourth switch 27 to be closed, so that the mains power source 20 or the AC power source stops supplying power to the first AC port 28 and the second The AC port 29 is configured to convert the discharged DC power of the electrical energy storage device 23 into AC power via the bidirectional power conversion circuit 21 and the DC-AC inverter circuit 22, and supply power to the first AC port 28 [first load 3] in parallel. As shown by the lower right dotted line and the direction of the arrow in Fig. 7, and the parallel supply of power to the second AC port 29 [second load 3'], as shown in the lower left and upper dashed lines and the direction of the arrow in Fig. 7.

Referring to FIG. 7 again, the fourth operating state of the dual port energy storage system 2 is: when the mains power source 20 or the AC power source fails, the first switch 24 and the third switch 26 maintain an open circuit. The second switch 25 and the fourth switch 27 are maintained to be closed, so that the first AC port 28 [the first load 3] and the second AC port 29 [the second load 3'] are not protected by the mains power source 20 or the AC. Power is interrupted due to power failure. At this time, the present invention can selectively convert the discharged DC power of the electrical energy storage device 23 into AC power via the bidirectional power conversion circuit 21 and the DC-AC inverter circuit 22, and supply the power to the first AC port 28 in parallel [the first load 3], as shown by the lower right dotted line and the direction of the arrow in Fig. 7, and the parallel supply of power to the second AC port 29 [second load 3'], as shown in the lower left and upper dashed lines and the direction of the arrow in Fig. 7.

Referring to FIG. 5 again, the fifth operational state of the dual port energy storage system 2 is: when the bidirectional power conversion circuit 21 or the DC-AC inverter circuit 22 fails or is repaired, the first A switch 24 and a second switch 25 are closed to enable the first AC port 28 [the first load 3] to be directly powered by the mains supply 20 or an AC power source. At this time, the commercial power source 20 or the AC power source directly supplies AC power to the second AC port 29 [second load 3'] via the third switch 26, as indicated by a broken line and an arrow direction on the fifth drawing.

The foregoing preferred embodiments are merely illustrative of the invention and the technical features thereof, and the techniques of the embodiments can be carried out with various substantial equivalent modifications and/or alternatives; therefore, the scope of the invention is subject to the appended claims. The scope defined by the scope shall prevail. The copyright limitation of this case is used for the purpose of patent application in the Republic of China.

2‧‧‧Dual Port Energy Storage System

20‧‧‧mains power supply

21‧‧‧Two-way power conversion circuit

22‧‧‧DC-AC inverter circuit

23‧‧‧Electric energy storage device

24‧‧‧First switch

25‧‧‧Second switch

26‧‧‧ Third switch

27‧‧‧fourth switch

28‧‧‧First AC port

29‧‧‧Second AC port

3‧‧‧First load

3'‧‧‧second load

A‧‧‧first connection point

B‧‧‧second connection point

Claims (14)

A dual-port energy storage system comprising: a bidirectional power conversion circuit having an AC terminal and a DC terminal; a DC-AC inverter circuit having a DC terminal and an AC terminal; and an electrical energy storage device Connected between the DC terminal of the bidirectional power conversion circuit and the DC terminal of the DC-AC inverter circuit; a first AC port connected to the AC terminal of the DC-AC inverter circuit; and a second AC port Connected between a mains power source or an AC power source and an AC terminal of the bidirectional power conversion circuit; a first switch connected between the mains power source or the AC power source and the AC end of the bidirectional power conversion circuit; a switch connected between a first connection point formed between the first switch and the AC end of the bidirectional power conversion circuit and the first AC port; a third switch connected to the mains power source or the AC power source and Between the second AC ports; and a fourth switch connected between a second connection point formed between the second switch and the first AC port and the second AC port; When the mains power source or the AC power source is normal, the first switch and the third switch are formed to be closed, and the second switch and the fourth switch are formed to be open, so that the mains power source or the AC power source directly supplies a mains level alternating current Providing a first quality AC power source to the second AC port, and operating the bidirectional power conversion circuit to convert the AC power of the mains power source or the AC power source into DC power to charge the power storage device, And converting the DC power of the bidirectional power conversion circuit into a stable AC power supply to the first AC port via the DC-AC inverter circuit, that is, the first AC port supplies a second quality AC power source, and the first The quality of the quality AC power source is not the same as the quality of the second quality AC power source to provide different quality AC power sources; When the mains power source or the AC power source is normal and the electric energy storage device is discharging, the first switch and the third switch are selected to be kept closed, and the second switch and the fourth switch are maintained to form an open circuit, so that the mains power source Or the AC power source directly supplies the commercial power level alternating current to the second AC port, that is, the second AC port still supplies the first quality AC power source, and converts the discharge DC power of the electric energy storage device via the DC-AC inverter circuit The stable AC power is supplied to the first AC port, that is, the first AC port still supplies the second quality AC power, and the selected DC power conversion device converts the discharged DC power into the AC power supply via the bidirectional power conversion circuit. To the mains power source or the AC power source; wherein when the mains power source or the AC power source fails or is repaired, the first switch and the third switch maintain an open circuit, and the second switch and the fourth switch maintain a closed state, and the selection is via The bidirectional power conversion circuit and the DC-AC inverter circuit put the electric energy storage device DC power into AC power, the AC power supply in parallel to said first port and a second AC port, at which time the first port and the second AC supply both AC port of the second AC power quality. The dual port energy storage system of claim 1, wherein the bidirectional power conversion circuit is selected from the group consisting of a combined circuit or device having a bidirectional power conversion function. The dual port energy storage system of claim 1, wherein the DC-AC inverter circuit is selected from a circuit or device having a DC-AC conversion function. The dual port energy storage system of claim 1, wherein the first AC port is connected to a first load. The dual port energy storage system of claim 1, wherein the second AC port is connected to a second load. According to the dual-port energy storage system of claim 1, wherein the first switch and the third switch maintain an open circuit when the mains power source or the AC power source fails, and the second switch and the fourth switch maintain the formation. Closed, so the first AC port and the second AC port are interrupted from power supply due to the mains power or AC power failure. The dual port energy storage system of claim 1, wherein when the bidirectional power conversion circuit or the DC-AC inverter circuit fails or is repaired, the first switch and the second switch are used to form a closed state, The first AC port is directly powered by the mains power source or the AC power source, and the mains power source or the AC power source directly supplies AC power to the second AC port via the third switch. A control method for a dual port energy storage system, comprising: a dual port energy storage system comprising a bidirectional power conversion circuit, a DC-AC inverter circuit, an electrical energy storage device, a first AC port, and a second AC port a first switch, a second switch, a third switch, and a fourth switch; the bidirectional power conversion circuit has an AC terminal and a DC terminal, and the DC-AC inverter circuit has an AC terminal and a DC current The power storage device is connected between the DC end of the bidirectional power conversion circuit and the DC end of the DC-AC inverter circuit, and the first AC port is connected to the AC end of the DC-AC inverter circuit, and the second The AC port is connected between a mains power source or an AC power source and an AC end of the bidirectional power conversion circuit, and the first switch is connected between the mains power source or the AC power source and the AC end of the bidirectional power conversion circuit, the second The switch is connected between a first connection point formed between the first switch and the first end of the bidirectional power conversion circuit and the first AC port, and the third opening Connected between the mains power source or the AC power source and the second AC port, the fourth switch is connected between a second connection point formed between the second switch and the first AC port and the second AC port When the mains power source or the AC power source is normal, the first switch and the third switch are formed to be closed, and the second switch and the fourth switch are formed to be open, so that the mains power source or the AC power source directly supplies a utility level alternating current Providing a first quality AC power source to the second AC port, and operating the bidirectional power conversion circuit to operate the mains power supply or Converting the AC power of the power source into DC power to charge the power storage device, and converting the DC power of the bidirectional power conversion circuit into a stable AC power to the first AC port via the DC-AC inverter circuit, that is, The first AC port is supplied with a second quality AC power source, and the quality of the first quality AC power source is different from the quality of the second quality AC power source to provide different quality AC power sources; when the mains power source or the AC power source is normal and When the electric energy storage device performs discharging, the first switch and the third switch are selected to be kept closed, and the second switch and the fourth switch are maintained to form an open circuit, so that the mains power source or the alternating current power source directly supplies the mains level alternating current to The second AC port, that is, the second AC port, still supplies the first quality AC power, and converts the discharged DC power of the electrical energy storage device into the stable AC power to the first through the DC-AC inverter circuit. An AC port, that is, the first AC port still supplies the second quality AC power source, and the selected The two-way power conversion circuit converts the discharged DC power of the electrical energy storage device into AC power to the mains power source or the AC power source; when the mains power source or the AC power source fails or performs maintenance, the first switch and the third switch are maintained Forming an open circuit, the second switch and the fourth switch are maintained to form a closed state, and selecting to discharge the discharged DC power of the electrical energy storage device into AC power via the bidirectional power conversion circuit and the DC-AC inverter circuit, and supplying the power in parallel to the first The AC port and the second AC port are both supplied by the first AC port and the second AC port. The control method of the dual port energy storage system according to claim 8 , wherein the bidirectional power conversion circuit is selected from the group consisting of a bidirectional power conversion circuit or a combined circuit or device having a bidirectional power conversion function. The control method of the dual port energy storage system according to claim 8, wherein the DC-AC inverter circuit is selected from a circuit or device having a DC-AC conversion function. According to the dual port energy storage system described in claim 8 The control method, wherein the first AC port is connected to a first load. The control method of the dual port energy storage system according to claim 8 , wherein the second AC port is connected to a second load. According to the control method of the dual port energy storage system described in claim 8, wherein the first switch and the third switch maintain an open circuit when the mains power source or the AC power source fails, the second switch and the fourth switch The switch remains closed, so that both the first AC port and the second AC port are interrupted from power supply due to the mains power or AC power failure. The control method of the dual port energy storage system according to claim 8 , wherein the first switch and the second switch are used when the bidirectional power conversion circuit or the DC-AC inverter circuit fails or performs maintenance Forming a closed state, the first AC port is directly powered by the mains power source or the AC power source, and the mains power source or the AC power source directly supplies the alternating current to the second AC port via the third switch.