TW202412424A - Rapid shutdown system of energy storage device and method thereof - Google Patents

Abstract

A rapid shutdown system of an energy storage device includes a battery module, a boost circuit, a second switch element and an output circuit. The battery module has a first end and a second end, the boost circuit includes a first switch element and an active or passive switch element, one end of the first switch element is connected to the active or passive switch element, the other end is connected to the second end, and the first switch element is controlled by a first control signal to conduct or not conduct between the first end and the second end. The second switching element has a third end and a fourth end, and the third end is connected to the active or passive switching element. The output circuit has a fifth end and a sixth end, an output voltage exists between the fifth terminal and the sixth terminal, the fifth end is connected to the fourth end, and the sixth end is connected to the second end. The second switch element is controlled by a second control signal to conduct or not conduct between the boost circuit and the output circuit.

Description

Rapid shutdown system for energy storage devices

The present invention relates to a shutdown system, and in particular to a fast shutdown system of an energy storage device.

Energy storage devices are modules such as lithium batteries, solar cells, and fuel cells. In order to improve the safety of energy storage devices, when a safety fault occurs, the energy storage device can be quickly shut down. When the safety fault disappears, the energy storage device can resume power generation. Generally speaking, each photovoltaic module in a solar photovoltaic system needs to be installed with a circuit breaker. When the safety fault disappears, the circuit breaker is reopened so that the photovoltaic module connected to the circuit breaker can output electricity. In other words, the current solar photovoltaic system needs to be equipped with a system controller to achieve a fast shutdown function under regulatory requirements. The additional equipment is a DC circuit breaker, a control logic relay, etc., which increases the construction cost.

The present invention relates to a fast shutdown system of an energy storage device, which can integrate a fast shutdown element into a boost circuit to reduce the construction cost.

According to one aspect of the present invention, a fast shutdown system of an energy storage device is proposed, comprising a battery module, a boost circuit, a second switch element and an output circuit. The battery module has a first end and a second end, and there is a DC voltage between the first end and the second end. The boost circuit includes a first switch element and an active or passive switch element. One end of the first switch element is connected to the active or passive switch element, and the other end is connected to the second end. The first switch element is controlled by a first control signal to conduct or not conduct between the first end and the second end. The second switch element has a third end and a fourth end, and the third end is connected to the active or passive switch element. The output circuit has a fifth end and a sixth end, and there is an output voltage between the fifth end and the sixth end. The fifth end is connected to the fourth end, and the sixth end is connected to the second end. The second switch element is controlled by a second control signal to conduct or not conduct between the boost circuit and the output circuit.

In order to better understand the above and other aspects of the present invention, the following embodiments are specifically described in detail with reference to the accompanying drawings:

The following will be combined with the attached drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the described embodiments are part of the embodiments of the present disclosure, but not all of the embodiments. Based on the embodiments in the present disclosure, all other embodiments obtained by a person of ordinary skill in the art on the premise of being obvious are within the scope of protection of this application. The following is an explanation of the same/similar elements represented by the same/similar symbols.

Please refer to FIG. 1A, which shows a schematic diagram of a rapid shutdown system 100 (rapid shutdown system) of an energy storage device according to an embodiment of the present invention. The rapid shutdown system 100 of the energy storage device includes a battery module 110, a boost circuit 120 including a first switch element 122 and a passive switch element (e.g., a diode 123), a second switch element 130, and an output circuit 140. The battery module 110 has a first terminal A1 and a second terminal A2, and a DC voltage Vi is provided between the first terminal A1 and the second terminal A2. One end of the first switch element 122 is connected to the passive switch element (e.g., the anode A7 of the diode 123), and the other end is connected to the second terminal A2. The first switch element 122 is controlled by a first control signal to conduct or not conduct between the first terminal A1 and the second terminal A2. The second switch element 130 has a third terminal A3 and a fourth terminal A4, and the third terminal A3 is connected to the passive switch element (for example, the cathode A8 of the diode 123). The output circuit 140 has a fifth terminal A5 and a sixth terminal A6, and there is an output voltage Vo between the fifth terminal A5 and the sixth terminal A6. The fifth terminal A5 is connected to the fourth terminal A4, and the sixth terminal A6 is connected to the second terminal A2. The second switch element 130 is controlled by a second control signal to conduct or not conduct between the boost circuit 120 and the output circuit 140.

In detail, the battery module 110 is, for example, a solar photovoltaic module or other type of energy storage module. The photovoltaic module can be composed of a plurality of series/parallel photovoltaic element arrays to output direct current, which can be converted into alternating current by a converter and then output to the power grid. Taking the solar photovoltaic module as an example, the solar photovoltaic module needs to convert the low voltage into a high voltage through a boost circuit 120, and then convert it into an alternating voltage output through a DC/AC converter (not shown). However, the voltage of the series/parallel photovoltaic element array is very high, so the battery module 110 needs to be additionally provided with a fast shutdown system 100 to improve the safety of the energy storage device. When a safety fault occurs, the energy storage device can be shut down quickly, and when the safety fault disappears, the energy storage device can resume power generation.

In this embodiment, the fast shutdown system 100 is integrated into the boost circuit 120, and no additional equipment such as a DC breaker or a control logic relay is required, thereby effectively reducing the construction cost.

As shown in FIG. 1A , the boost circuit 120 includes a boost capacitor C1 and a boost inductor L1 in addition to the first switch element 122 and the diode 123. In addition, the output circuit 140 also includes an output capacitor C2 and an output resistor R1. The output capacitor C2 and the output resistor R1 are connected in parallel between the fifth terminal A5 and the sixth terminal A6 of the output circuit 140.

As shown in FIG. 1A , two ends of the boost capacitor C1 are connected to the first end A1 and the second end A2 of the battery module 110 , respectively. Two ends of the boost inductor L1 are connected to the first end A1 and the anode A7 of the diode 123 , respectively. The first switch element 122 is, for example, a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT), wherein the insulated gate bipolar transistor (IGBT) is a composite semiconductor power element composed of a bipolar junction transistor (BJT) and a MOSFET. The control end (gate G1) of the first switch element 122 is connected to a controller (not shown, such as a microcontroller MCU), and the controller can generate the above-mentioned first control signal (such as a pulse width modulation signal) to turn on or off the first switch element 122. By turning on or off the first switch element 122, the DC voltage Vi generated by the battery module 110 is boosted to the output voltage Vo.

In addition, the diode 123 is a unidirectional conductive element, which only allows current to flow from the anode A7 of the diode 123 to the cathode A8, but does not allow current to flow from the cathode A8 of the diode 123 to the anode A7, thereby blocking the reverse current flowing from the output circuit 140 to the boost circuit 120. The diode 123 can be turned on or off in response to the first switch element 122 being turned on or off.

Please refer to FIG. 1B , when the first switch element 122 is turned on, the voltage at the anode A7 of the diode 123 is lower than the output voltage Vo of the output circuit 140. At this time, the diode 123 is reverse biased and does not conduct. The current I _AV passes through the boost inductor L1 in a clockwise direction. The boost inductor L1 begins to generate a magnetic field to store energy. Therefore, the current I _AV of the boost inductor L1 increases, and the boost capacitor C1 is charged. The output capacitor C2 of the output circuit 140 releases energy to the output resistor R1. The output voltage of the output resistor R1 is Vo, and the current of the output resistor R1 is Io.

Referring to FIG. 1C , when the first switch element 122 is not conducting, the voltage at the anode A7 of the diode 123 is higher than the output voltage Vo of the output terminal. At this time, the diode 123 is forward biased and turned on, the current I _AC of the boost inductor L1 flows to the output circuit 140, and the boost capacitor C1 is discharged. The current I _AV continues to flow through the boost inductor L1 in a clockwise direction, but the current I _AV decreases and charges the output capacitor C2 through the diode 123. The electric energy of the output capacitor C2 increases due to the integration of the electric energy of the battery module 110, the electric energy of the boost capacitor C1, and the electric energy of the boost inductor L1. Therefore, the output capacitor C2 can store more electric energy, thereby boosting the output voltage Vo, and the current Io of the output resistor R1 also increases relatively.

As can be seen from the above description, the boost circuit 120 can boost the DC voltage Vi generated by the battery module 110 to the output voltage Vo and output it through the output circuit 140 by turning on or off the first switch element 122 .

Please refer to FIG. 2, which shows a schematic diagram of a fast shutdown system 100' of an energy storage device according to another embodiment of the present invention. The difference between this embodiment and the above-mentioned embodiment is that the diode 123 is replaced by an active switch element 124. The active switch element 124 is, for example, a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT). The control end (gate G3) of the active switch element 124 is connected to a controller (not shown, such as a microcontroller MCU), and the controller can generate a control signal (such as a pulse width modulation signal) to turn the active switch element 124 on or off.

When the first switch element 122 is turned on, the active switch element 124 is controlled to be non-conductive, just like the diode 123 is reverse biased and non-conductive. At this time, the output capacitor C2 of the output circuit 140 releases energy to the output resistor R1, the output voltage of the output resistor R1 is Vo, and the current of the output resistor R1 is Io. When the first switch element 122 is not turned on, the active switch element 124 is controlled to be turned on, just like the diode 123 is forward biased and turned on. At this time, the output capacitor C2 can store more electrical energy, thereby boosting the output voltage Vo, and the current Io of the output resistor R1 is also relatively increased.

In addition, please refer to Figures 1A and 2, the third terminal A3 of the second switch element 130 is connected to the cathode A8 of the diode 123 (see Figure 1A) or to one end of the active switch element 124 (see Figure 2), and the fourth terminal A4 is connected to the fifth terminal A5 of the output circuit 140. The second switch element 130 is, for example, a metal oxide semiconductor field effect transistor (MOSFET) or an insulated gate bipolar transistor (IGBT), and the control terminal (gate G2) of the second switch element 130 is connected to a controller (not shown, such as a microcontroller MCU), and the controller can generate a second control signal (such as a pulse width modulation signal) to turn on or off the second switch element 130. The fast shutdown system 100 is turned on or off by turning on or off the second switch element 130.

In addition, referring to FIG. 1A , the second switch element 130 can form a bidirectional cutoff switch element group with the diode 123, or the second switch element 130 can form an insulated gate bipolar transistor (IGBT) with the diode 123. Referring to FIG. 2 , the second switch element 130 can form a source-to-source MOSFET switch element group with the active switch element 124. In other words, the second switch element 130 can be integrated with the boost circuit 120 as a fast turn-off element to reduce the construction cost.

Please refer to FIG. 3, which shows the waveforms of the first switch element 122, the diode 123, the second switch element 130 and the inductor current I _AV . When the first switch element 122 is turned on, the diode 123 is reverse biased (non-conducting); and when the first switch element 122 is not conducting, the diode 123 is forward biased (conducting). Therefore, the waveforms of the first switch element 122 and the diode 123 in the same cycle are opposite to each other. In addition, the waveform of the inductor current I _AV also increases or decreases relatively as the first switch element 122 is turned on or off. In addition, when the second switch element 130 is turned on, the fast turn-off system 100 is not turned on, so the waveform of the inductor current I _AV is not affected. When the second switch element 130 is not turned on, the fast turn-off system 100 is turned on, and the inductor current I _AV between the boost circuit 120 and the output circuit 140 is blocked, so the inductor current I _AV cannot be output.

Please refer to Figures 4 and 5, which respectively show schematic diagrams of rapid shutdown systems 101 and 101' of energy storage devices according to two other embodiments of the present invention.

The fast shutdown system 101, 101' of the energy storage device includes a battery module 110, a boost circuit 120 including a first switch element 122 and an active or passive switch element (123, 124), a second switch element 130 and an output circuit 140. The battery module 110 has a first terminal A1 and a second terminal A2, and a DC voltage Vi is provided between the first terminal A1 and the second terminal A2. One end of the first switch element 122 is connected to the active or passive switch element (123, 124), and the other end is connected to the second terminal A2. The first switch element 122 is controlled by a first control signal to conduct or not conduct between the first terminal A1 and the second terminal A2. The second switch element 130 has a third terminal A3 and a fourth terminal A4, and the fourth terminal A4 is connected to the second terminal A2. The output circuit 140 has a fifth terminal A5 and a sixth terminal A6, an output voltage Vo is present between the fifth terminal A5 and the sixth terminal A6, the fifth terminal A5 is connected to the active or passive switch element (123, 124), and the sixth terminal A6 is connected to the third terminal A3 of the second switch element 130. The second switch element 130 is controlled by a second control signal to conduct or not conduct between the boost circuit 120 and the output circuit 140.

In FIGS. 4A and 5, except that the configuration of the second switch element 130 is different from that of the second switch element 130 in FIGS. 1A and 2, the other elements are substantially the same and will not be described again. Referring to FIG. 4A, the second switch element 130 has a third terminal A3 and a fourth terminal A4. The third terminal A3 is connected to the sixth terminal A6 of the output circuit 140, and the fourth terminal A4 is connected to the second terminal A2 of the battery module 110. The second switch element 130 and the diode 123 are respectively connected to the two ends of the output capacitor C2. The second switch element 130 can form a bidirectional cutoff switch element group with the diode 123, or the second switch element 130 can form an insulated gate bipolar transistor (IGBT) with the diode 123.

Please refer to FIG. 4B , when the first switch element 122 is turned on, the diode 123 is reverse biased and does not conduct. Please refer to FIG. 4C , when the first switch element 122 is not turned on, the diode 123 is forward biased and conducts. The control method is the same as that shown in FIG. 1B and FIG. 1C , and will not be repeated here.

In addition, referring to FIG. 5 , the second switch element 130 and the active switch element 124 are connected to two ends of the output capacitor C2 respectively. The second switch element 130 and the active switch element 124 can form a bidirectional cutoff switch element set.

According to the above description, the present invention provides a fast shutdown method for the fast shutdown system 100, 100', 101, 101' of the energy storage device. In a normal state, a first control signal is input to control (e.g., a gate voltage signal) the first switch element 122 to be turned on or off, wherein when the first switch element 122 is turned on, the active or passive switch elements 123, 124 are not turned on; when the first switch element 122 is not turned on, the active or passive switch elements 123, 124 are turned on. When the system determines that a safety fault occurs in the battery module 110, a second control signal (e.g., a gate voltage signal is lowered) is input to control the second switch element 130 so that the second switch element 130 is not conducting between the boost circuit 120 and the output circuit 140; when the system determines that the safety fault of the battery module 110 disappears, a second control signal (e.g., a gate voltage signal is increased) is input to control the second switch element 130 so that the second switch element 130 is conducting between the boost circuit 120 and the output circuit 140.

The fast shutdown system of the energy storage device of the above embodiment of the present invention is integrated into the boost circuit, and does not require additional equipment such as a DC breaker or a control logic relay, thereby effectively reducing the construction cost.

In summary, although the present invention has been disclosed as above by way of embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention belongs can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be subject to the scope defined in the attached patent application.

100, 100', 101, 101': Fast shutdown system of energy storage device 110: Battery module 120: Boost circuit 122: First switch element 123: Diode 124: Active switch element 130: Second switch element 140: Output circuit A1: First terminal A2: Second terminal A3: Third terminal A4: Fourth terminal A5: Fifth terminal A6: Sixth terminal A7: Anode A8: Cathode C1: Boost capacitor C2: Output capacitor L1: Boost inductor R1: Output resistor G1, G2, G3: Gate Vi: DC voltage Vo: Output voltage I _AV : Inductor current Io: Output current

FIG. 1A is a schematic diagram of a fast shutdown system of an energy storage device according to an embodiment of the present invention; FIG. 1B and FIG. 1C are schematic diagrams of a first switch element when it is conducting and when it is not conducting, respectively; and FIG. 2 is a schematic diagram of a fast shutdown system of an energy storage device according to another embodiment of the present invention; FIG. 3 is a waveform diagram of the first switch element, the diode/active switch element, the second switch element, and the inductor current; FIG. 4A and FIG. 5 are schematic diagrams of a fast shutdown system of an energy storage device according to another two embodiments of the present invention, respectively; and FIG. 4B and FIG. 4C are schematic diagrams of a first switch element when it is conducting and when it is not conducting, respectively.

100: Rapid shutdown system of energy storage device

110:Battery module

120: Boost circuit

122: First switch element

123: Diode

130: Second switch element

140: Output circuit

A1: First end

A2: Second end

A3: The third end

A4: The fourth end

A5: The fifth end

A6: The sixth end

A7: Anode

A8: cathode

C1: boost capacitor

C2: output capacitor

L1: boost inductor

R1: output resistor

G1,G2: Gate

Vi: DC voltage

Vo: output voltage

Claims (20)

A fast shutdown system for an energy storage device, comprising: a battery module having a first end and a second end; a boost circuit, comprising a first switch element and an active or passive switch element, one end of the first switch element is connected to the active or passive switch element, and the other end is connected to the second end, and the first switch element is controlled by a first control signal to conduct or not conduct between the first end and the second end; a second switch element having a third end and a fourth end, and the third end is connected to the active or passive switch element; and an output circuit having a fifth end and a sixth end, and an output voltage is provided between the fifth end and the sixth end, the fifth end is connected to the fourth end, and the sixth end is connected to the second end, wherein the second switch element is controlled by a second control signal to conduct or not conduct between the boost circuit and the output circuit. A fast shutdown system as described in claim 1, wherein the boost circuit further includes a boost capacitor and a boost inductor, the two ends of the boost capacitor are respectively connected to the first end and the second end, and the two ends of the boost inductor are respectively connected to the first end and the active or passive switching element. A fast shutdown system as described in claim 1, wherein the passive switching element is a diode. A fast shutdown system as described in claim 3, wherein when the first switching element is turned on, the diode is reverse biased and does not conduct; when the first switching element is not conducting, the diode is forward biased and conducts. A fast shutdown system as described in claim 3, wherein the second switch element and the diode form a bidirectional cutoff switch element set or an insulated gate bipolar transistor. A fast shutdown system as described in claim 1, wherein the active switching element is a metal oxide semiconductor field effect transistor (MOSFET). A fast shutdown system as described in claim 7, wherein the second switch element and the active switch element form a MOSFET switch element group with source terminals connected to each other. A fast shutdown system as described in claim 1, wherein the output circuit includes an output capacitor and an output resistor, and the output capacitor is connected in parallel with the output resistor between the fifth terminal and the sixth terminal of the output circuit. A fast shutdown system for an energy storage device, comprising: a battery module having a first end and a second end; a boost circuit, comprising a first switch element and an active or passive switch element, one end of the first switch element is connected to the active or passive switch element, and the other end is connected to the second end, and the first switch element is controlled by a first control signal to conduct or not conduct between the first end and the second end; a second switch element having a third end and a fourth end, and the fourth end is connected to the second end; and an output circuit having a fifth end and a sixth end, and an output voltage is provided between the fifth end and the sixth end, the fifth end is connected to the active or passive switch element, and the sixth end is connected to the third end of the second switch element, wherein the second switch element is controlled by a second control signal to conduct or not conduct between the boost circuit and the output circuit. A fast shutdown system as described in claim 9, wherein the boost circuit further includes a boost capacitor and a boost inductor, the two ends of the boost capacitor are respectively connected to the first end and the second end, and the two ends of the boost inductor are respectively connected to the first end and the active or passive switching element. A fast shutdown system as described in claim 9, wherein the passive switching element is a diode. A fast shutdown system as described in claim 11, wherein when the first switching element is turned on, the diode is reverse biased and non-conducting; when the first switching element is not conducting, the diode is forward biased and turned on. A fast shutdown system as described in claim 11, wherein the second switch element and the diode form a bidirectional cutoff switch element set or an insulated gate bipolar transistor. A fast shutdown system as described in claim 10, wherein the active switching element is a metal oxide semiconductor field effect transistor (MOSFET). A fast shutdown system as described in claim 9, wherein the first switching element and the second switching element are metal oxide semiconductor field effect transistors (MOSFETs). A fast shutdown system as described in claim 9, wherein the output circuit includes an output capacitor and an output resistor, and the output capacitor is connected in parallel with the output resistor between the fifth terminal and the sixth terminal of the output circuit. A fast shutdown method for a fast shutdown system of an energy storage device as described in claim 1 or 9, comprising: Inputting a first control signal to control the first switch element to be conductive or non-conductive, wherein when the first switch element is conductive, the active or passive switch element is non-conductive; when the first switch element is non-conductive, the active or passive switch element is conductive; and Inputting a second control signal to control the second switch element, so that the second switch element is conductive or non-conductive between the boost circuit and the output circuit. A fast shutdown method as described in claim 17, wherein the passive switching element is a diode, and the second switching element and the diode form a bidirectional cutoff switching element group or an insulated gate bipolar transistor. A fast shutdown method as described in claim 17, wherein the second switch element and the active switch element form a MOSFET switch element group with source terminals connected to each other. A fast shutdown method as described in claim 17, wherein the second switch element and the active switch element form a bidirectional cutoff switch element set.