Fault detection device

Abstract

A fault detection device according to one embodiment of the present invention includes a plurality of resistors connected in series between both ends of an input terminal of a converter, a sensing circuit that measures a first voltage at one of the nodes between the plurality of resistors, and a processing unit that detects a fault using a change in the first voltage.

Description

[Technical Field]

[0001] The present invention relates to a fault detection device, and more specifically to a fault detection device, a converter, and a battery pack capable of detecting a touch fault. [Background technology]

[0002] Recently, with the growing awareness of environmental protection, there has been a surge in interest in methods for generating electricity without emitting pollutants such as carbon dioxide. In particular, solar power generation systems are becoming increasingly popular due to technological advances that have made the development and installation costs of the technology cheaper.

[0003] Such a solar power generation system consists of multiple photovoltaic cells grouped together to form multiple photovoltaic modules, and the DC power generated from the multiple photovoltaic modules is converted into AC power via an inverter and can be immediately used in homes and industrial facilities.

[0004] On the other hand, solar power generation is subject to power production gaps due to nighttime when there is no sunlight or changes in the weather. To compensate for these shortcomings, solar power generation systems must be equipped with batteries to ensure a stable power supply.

[0005] A home solar system including a battery can be configured as shown in Figure 1. The battery pack can be configured with a battery, BMS, and DC-DC converter. If a problem within the battery pack causes the battery inside the battery pack to come into contact with the battery pack housing, problems can occur in the entire system, and a technology to detect such a fault is required. Summary of the Invention [Problem to be solved by the invention]

[0006] The technical problem to be solved by the present invention is to provide a fault detection device, a converter, and a battery pack that are capable of detecting a touch fault. [Means for solving the problem]

[0007] In order to solve the above technical problems, a fault detection device according to one embodiment of the present invention includes a plurality of resistors connected in series between both ends of an input terminal of a converter, a sensing circuit that measures a first voltage of one of the nodes between the plurality of resistors, and a processing unit that detects a fault using a change in the first voltage.

[0008] In addition, the plurality of resistors may include a first resistor, a second resistor, and a third resistor connected in series in order from the positive terminal to the negative terminal of the input terminal, a node between the first resistor and the second resistor may be connected to a case of the converter, and the sensing circuit may measure the first voltage at the node between the second resistor and the third resistor.

[0009] The sensing circuit may include an inverting amplifier and a non-inverting amplifier to which the first voltage is respectively input, and outputs of the inverting amplifier and the non-inverting amplifier may be applied to the processing unit.

[0010] The amplifier may also include a first low-pass filter that filters the output of the non-inverting amplifier and a second low-pass filter that filters the output of the inverting amplifier, and the output of the non-inverting amplifier and the output of the inverting amplifier may be applied to the processing unit via the first low-pass filter and the second low-pass filter, respectively.

[0011] Furthermore, the processing unit can detect a fault using the difference between the output of the inverting amplifier and the output of the non-inverting amplifier.

[0012] In addition, the output end of the converter is connected to a grid, and the processing unit filters the difference between the output of the inverting amplifier and the output of the non-inverting amplifier using a band-pass filter that filters the frequency band of the grid, and can detect a fault by comparing the magnitude level of the filtered difference between the output of the inverting amplifier and the output of the non-inverting amplifier with a reference level.

[0013] In addition, the processing unit can determine that a failure has occurred if the magnitude level of the difference between the filtered output of the inverting amplifier and the output of the non-inverting amplifier is smaller than the reference level for a predetermined time or longer.

[0014] Furthermore, the processing unit can cut off connection of at least one of the input terminal and the output terminal of the converter when a fault is detected.

[0015] In addition, the converter is a DC-DC converter inside a battery pack, and the processing unit can detect contact or ground fault of the batteries in the battery pack.

[0016] In addition, the converter is a DC-DC converter connected to a solar power generation module, and the processing unit can detect contact or ground fault of at least one of the terminals at both ends of the solar power generation module input terminal of the DC-DC converter.

[0017] In order to solve the above technical problems, a DC-DC converter according to one embodiment of the present invention includes an input terminal connected to a battery or a solar panel, and a fault detection circuit that detects contact or ground fault of at least one terminal at both ends of the input terminal, and the fault detection circuit includes any one of the fault detection devices described above.

[0018] In order to solve the above technical problems, a battery pack according to one embodiment of the present invention includes a battery, a DC-DC converter that converts the voltage of the battery, and a fault detection circuit that detects contact or grounding fault of the battery, the fault detection circuit including any one of the fault detection devices described above, and cutting off connection with the outside when contact or grounding fault of the battery is detected. [Effects of the Invention]

[0019] According to the embodiment of the present invention, it is possible to detect a battery power supply contact fault (dielectric breakdown) in a power conversion system for photovoltaic and grid-connected ESS. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a diagram illustrating a photovoltaic power generation system to which a failure detection device according to an embodiment of the present invention is applied;

[0021] [Figure 2] 1 is a block diagram of a fault detection device according to an embodiment of the present invention;

[0022] [Figure 3] 1 is a block diagram of a fault detection device according to an embodiment of the present invention;

[0023] [Figure 4] 1 is a diagram for explaining a fault detection device according to an embodiment of the present invention; [Figure 5] 1 is a diagram for explaining a fault detection device according to an embodiment of the present invention; [Figure 6] 1 is a diagram for explaining a fault detection device according to an embodiment of the present invention; [Figure 7] 1 is a diagram for explaining a fault detection device according to an embodiment of the present invention;

[0024] [Figure 8] 1 is a diagram showing an example of application to which a fault detection device according to an embodiment of the present invention is applied; [Figure 9]1 is a diagram showing an example of application to which a fault detection device according to an embodiment of the present invention is applied;

[0025] [Figure 10] 1 is a block diagram of a DC-DC converter according to an embodiment of the present invention.

[0026] [Figure 11] 1 is a block diagram of a battery pack according to an embodiment of the present invention.

[0027] [Figure 12] 2 is a flowchart of a fault detection method according to an embodiment of the present invention.

[0028] [Figure 13] 2 is a flowchart of a fault detection method according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0029] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0030] However, the technical concept of the present invention is not limited to the described embodiments, but can be realized in various different forms, and one or more of the components of the embodiments can be selectively combined or substituted and used within the scope of the technical concept of the present invention.

[0031] Furthermore, unless otherwise clearly defined and described, terms (including technical and scientific terms) used in the embodiments of the present invention may be interpreted in a meaning that is commonly understood by a person having ordinary knowledge in the technical field to which the present invention belongs, and commonly used terms, such as terms defined in a dictionary, may be interpreted in light of the contextual meaning of the relevant art.

[0032] Furthermore, the terms used in the examples of the present invention are intended to explain the examples and are not intended to limit the present invention.

[0033] In this specification, unless otherwise specified in the phrase, the singular can also include the plural, and when it says "A and (and) at least one (or more) of B and C," it can include one or more of all possible combinations of A, B, and C.

[0034] Furthermore, in describing components of the embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. are used only to distinguish the component from other components, and the terms do not limit the essence, order, or sequence of the components.

[0035] Furthermore, when a component is described as being "coupled," "coupled," or "connected" to another component, it can include not only cases where the component is directly "coupled," "coupled," or "connected" to the other component, but also cases where the component is "coupled," "coupled," or "connected" by another component between the component and the other component.

[0036] Furthermore, when it is described as being formed or disposed "above (above)" or "below (below)" each component, "above (above)" or "below (below)" includes not only the case where two components are in direct contact with each other, but also the case where one or more other components are formed or disposed between the two components. Furthermore, when it is expressed as "above (above)" or "below (below)", it can include not only the upper direction but also the lower direction based on one component.

[0037] Modifications of the present embodiments may include some components of each embodiment and some components of other embodiments. That is, a modification may include one of the various embodiments, but omit some components, and include some components of the corresponding other embodiment. Or vice versa. Features, structures, effects, etc. described in the embodiments are included in at least one embodiment and are not necessarily limited to only one embodiment. Furthermore, features, structures, effects, etc. exemplified in each embodiment may be combined or modified with other embodiments by a person skilled in the art to which the embodiment belongs. Therefore, content related to such combinations and modifications should be interpreted as being included within the scope of the embodiments.

[0038] FIG. 1 is a diagram illustrating a photovoltaic power generation system to which a fault detection device according to an embodiment of the present invention is applied.

[0039] As shown in Fig. 1, the solar power generation system may include a solar power source 10, an inverter 20, a battery pack 30, and a load 50. However, a person skilled in the relevant art will understand that the solar power generation system may further include other general components in addition to the components shown in Fig. 1. For example, the solar power generation system may further include a grid 40. Alternatively, a person skilled in the relevant art will understand that in other embodiments, some of the components shown in Fig. 1 may be omitted.

[0040] The solar power source 10 may be composed of multiple photovoltaic modules, each consisting of an array of solar cells. Photovoltaic cells, each consisting of a P-type semiconductor and an N-type semiconductor, generate electricity using light. Specifically, when light shines on a solar cell, electrons and holes are generated inside. The generated charges move to the P and N poles, respectively, creating a potential difference between the P and N poles. When a load is connected to the solar cell, current flows. Here, a solar cell is the smallest unit for generating electricity. Solar cell cells are grouped together to form a battery module, and battery modules can also be connected in series or parallel to form an array to configure the solar power source 10.

[0041] The inverter 20 converts DC (direct current) power generated by the solar power source 10 through the photovoltaic effect into AC (alternating current) power for supply to the grid 40 or the load 50. Here, the grid 40 may refer to a system for transmitting and distributing power generated by a solar power generation system. Meanwhile, the amount of power generated by the solar power source 10 varies depending on time factors such as sunrise and sunset and external factors such as weather. Therefore, the inverter 20 controls the voltage generated by the solar power source 10 to find maximum power and supply it to the grid 40. In this case, if the power required to operate the inverter is lower than the inverter's output power, the inverter 20 may reversely consume power from the grid 40. Of course, in this case, the inverter can block power flowing into the grid 40 to prevent power reversal. Therefore, various optimizer control methods are applied to the solar power generation system to extract maximum power from the solar power source 10 so that the inverter 20 operates more efficiently. Representative maximum power point (MPP) methods for the solar power source 10 include the perturbation and observation (PO) method, the incremental conductance (IC) control method, and the constant voltage (CV) control method. The PO method periodically measures the voltage and current of the solar power source 10, calculates the power, and then tracks the MPP using the power value. The IC control method measures the voltage and current generated by the solar power source 10 and controls the power so that the rate of change in power relative to a change in the operating point of the array terminal voltage is '0'. The CV control method controls the solar power source 10 at a constant reference voltage (ref V) regardless of the operating voltage or power of the array. Depending on each optimizer control method, the power source input from the solar power source 10 to the inverter can operate as a voltage source or a current source.

[0042] The load 50 may refer to a product that uses electricity in a real-life form. For example, the inverter 20 can obtain AC power of a desired voltage and frequency through an appropriate conversion method, switching element, and control circuit, and supply electricity to household appliances or industrial machinery. Furthermore, in the case of solar power generation, there are inevitably gaps in power production due to insufficient power generation at night when there is no sunlight or due to weather changes. Therefore, to compensate for these shortcomings, a battery is essential for a solar power generation system to ensure a stable power supply.

[0043] The battery pack 30 may include at least one of a DC-DC converter, a battery, a battery management system (BMS), and a battery control circuit. The battery may be, but is not limited to, a lithium-ion battery or a nickel-metal hydride battery. It may refer to a battery that can be used semi-permanently by charging. The DC-DC converter converts DC power generated by the solar power source 10 into DC power suitable for a battery or converts battery power into power suitable for the grid. It typically converts DC power into AC power and then converts AC power back into DC power. The battery management system (BMS) may provide functions such as protection against misuse of cells constituting the battery, balancing between unit cells, measuring the state of charge (SOC), maintaining temperature, and system monitoring. Therefore, based on a sensor that measures the cell status and a function that receives and transmits the sensor's measurement value to the control system of the application product, it may generate an abnormal signal and establish and control a circuit that cuts or opens the power circuit between cells when the system temperature and state of charge exceed preset values.

[0044] Fig. 2 is a block diagram of a fault detection device according to an embodiment of the present invention. Fig. 3 is a block diagram of a fault detection device according to an embodiment of the present invention. Figs. 4 to 7 are diagrams for explaining the fault detection device according to an embodiment of the present invention. Figs. 8 and 9 show application examples to which the fault detection device according to an embodiment of the present invention is applied.

[0045] The fault detection device 100 according to an embodiment of the present invention detects faults due to contact or faulty grounding. Contact refers to an input / output terminal being electrically connected to a case (housing) despite being insulated from the case. A ground fault may occur due to insulation breakdown or the like. A faulty ground refers to an abnormal grounding state, such as when the ground terminal contacts a different position than the normal position due to an external impact or the like. Contact or faulty grounding may cause damage to the inside of the device or other connected devices when connecting to a battery or power device, and may also generate an overcurrent, which may lead to a risk of fire, such as an explosion. To prevent this, it is necessary to quickly detect the occurrence of a contact or faulty grounding.

[0046] In order to detect a fault such as a touch fault or a ground fault, the fault detection device 100 according to the embodiment of the present invention comprises a plurality of resistors 110, a sensing circuit 120, and a processing unit .

[0047] A plurality of resistors 110 are connected in series between both ends of the input terminal 210 of the converter, a sensing circuit 120 measures a first voltage at one of the nodes between the plurality of resistors 110, and a processing unit 130 detects a fault using a change in the first voltage.

[0048] The input terminal 210 may be a connection terminal of the converter. Although it is called an input terminal, it may also be an input / output terminal where power is input and output. The input terminal 210 may include both a positive terminal and a negative terminal. Here, the converter may be a converter used in a solar power generation system, a DC-DC converter included in a battery pack of the solar power generation system, or a DC-DC converter connected to a solar power generation panel. It goes without saying that the converter may also be applied to converters of various other devices that input and output power.

[0049] The plurality of resistors 110 includes a first resistor 111, a second resistor 112, and a third resistor 113 connected in series from the positive terminal to the negative terminal of the input port 210. A node between the first resistor 111 and the second resistor 112 is connected to a case 220 of the converter, and the sensing circuit 120 can measure the first voltage at a node between the second resistor 112 and the third resistor 113. To detect whether a contact fault occurs in one of the positive and negative terminals, the first voltage is measured between a resistor connecting the positive and negative terminals. To detect a change in the first voltage due to contact with the case 220, the terminal between the first resistor 111 and the second resistor 112 is connected to the case 220. Therefore, the voltage at the node between the first resistor 111 and the second resistor 112 is equal to the case 220, and the case 220 may correspond to the lowest voltage of a device to which the converter is attached. The first voltage is measured by sensing the voltage at the terminal between the second resistor 112 and the third resistor 113 .

[0050] The sensing circuit 120 measures a first voltage and includes a non-inverting amplifier 121 and an inverting amplifier 122, to which the first voltage is input, and transmits the outputs of the inverting amplifier 122 and the non-inverting amplifier 121 to the processing unit 130. The converter input terminal 210 may be connected to a battery or a solar panel, and the converter output terminal may be connected to the grid. The grid uses AC voltage and has a trigonometric waveform with a constant frequency rather than a constant voltage value. For example, the grid may have a frequency of 60 Hz in a single-phase line-to-line (LL) system or a frequency of 50 Hz in a single-phase line-to-neutral (LN) system. This may affect the voltage at both terminals of the converter input terminal, causing ripples. Furthermore, under normal conditions, the first voltage has a predetermined offset value but fluctuates at a predetermined frequency. In this case, if a contact fault occurs between the positive terminal or the negative terminal of the input terminal 210, the value of the first voltage may vary depending on whether the positive terminal or the negative terminal contacts the case 220. Therefore, to detect both cases, the first voltage is not used as is, but is transmitted to the processing unit 130 via the inverting amplifier 122 and the non-inverting amplifier 121. Here, the inverting amplifier 122 and the non-inverting amplifier 121 each act as a buffer, with the non-inverting amplifier 121 having the same phase and the inverting amplifier 122 having an inverted phase.

[0051] The amplifier includes a first low pass filter (LPF) 123 that filters the output of the non-inverting amplifier 121 and a second low pass filter 124 that filters the output of the inverting amplifier 122, and the output of the non-inverting amplifier 121 and the output of the inverting amplifier 122 can be applied to a processing unit 130 via the first low pass filter 123 and the second low pass filter, respectively. Although the output of the non-inverting amplifier 121 and the output of the inverting amplifier 122 may contain noise, the noise can be removed via the low pass filters so that only the required signal can be applied to the processing unit 130.

[0052] The processing unit 130 may be a micro control unit (MCU) as shown in FIG. 4, and may receive signals via an analog-to-digital converter (ADC) so that the processing unit 130 can use the corresponding values. That is, the output of the non-inverting amplifier 121 and the output of the inverting amplifier 122, which have passed through low-pass filters (LPFs) 123 and 124, may be received via ADC1 (131) and ADC2 (132), respectively. The processing unit 130 may detect a fault using the difference between the output of the inverting amplifier and the output of the non-inverting amplifier. The output of the inverting amplifier and the output of the non-inverting amplifier have opposite phases, and therefore may be represented by a trigonometric waveform having a predetermined phase regardless of the offset value of the first voltage, regardless of the offset value.

[0053] The processing unit 130 filters the difference between the output of the inverting amplifier and the output of the non-inverting amplifier using a band pass filter (BPF) that filters the frequency band of the grid, and compares the magnitude level of the filtered difference between the output of the inverting amplifier and the output of the non-inverting amplifier with a reference level to detect a fault. Since the frequency of the difference between the output of the inverting amplifier and the output of the non-inverting amplifier is affected by the frequency of the grid, the processing unit 130 removes the offset of the first voltage through the difference between the output of the inverting amplifier and the output of the non-inverting amplifier, and then filters the difference between the output of the inverting amplifier and the output of the non-inverting amplifier using a band pass filter (BPF) that filters the frequency band of the grid. This removes noise and allows only the signal for fault detection to be used. The processing unit 130 then calculates the magnitude level of the voltage difference between the filtered output of the inverting amplifier and the output of the non-inverting amplifier and compares it with a reference level. When a touch fault or ground fault occurs, the connection to the case 220 reduces fluctuations in the first voltage due to the influence of the grid. That is, when the magnitude level of the difference voltage between the filtered output of the inverting amplifier and the output of the non-inverting amplifier decreases, the processing unit 130 compares it with a reference level, and if the magnitude level of the difference voltage between the filtered output of the inverting amplifier and the output of the non-inverting amplifier is smaller than the reference level, it can be determined that a fault has occurred. The reference level can be determined by design or simulation results, or can be set by the user.

[0054] The processing unit 130 may determine a fault if the magnitude level of the difference between the filtered output of the inverting amplifier and the output of the non-inverting amplifier is smaller than the reference level for a predetermined time or longer. The magnitude level of the difference between the filtered output of the inverting amplifier and the output of the non-inverting amplifier may temporarily become smaller than the reference level for a short period of time due to a change in the configuration of the grid or a part of the overall system. Even in such a case, the system may continue to operate in a safe mode without immediately determining a fault. If the determination time is temporary, the system may continue to operate without determining a fault. The time period for determining whether a fault has occurred may be set to a minimum time that does not cause damage to the battery, etc., and may be determined through design or simulation, or may be set by the user.

[0055] The processing unit 130 may disconnect at least one of the input and output terminals of the converter when a fault is detected. If it is determined that a fault has occurred through the fault determination, the processing unit 130 may disconnect at least one of the input and output terminals of the converter connected to a device that may be damaged by contact in order to prevent the device from being damaged. The input or output terminal of the converter may be connected to a circuit breaker. Here, the circuit breaker may include a switch or may be a CB (Circuit Breaker). Alternatively, the circuit breaker may include various devices capable of disconnecting a connection, such as a relay.

[0056] The process of detecting a touch fault and disconnecting the connection when a touch fault is detected may be performed as shown in Figure 5. When a circuit breaker (CB) is connected, it senses a first voltage and receives the output of the inverting amplifier and the output of the non-inverting amplifier using an inverting amplifier and a non-inverting amplifier. The difference between the output of the inverting amplifier and the output of the non-inverting amplifier is calculated. The grid frequency is determined based on the grid type, and the difference between the output of the inverting amplifier and the output of the non-inverting amplifier is filtered using a bandpass filter that filters the corresponding band. The magnitude level of the difference between the filtered output of the inverting amplifier and the output of the non-inverting amplifier is then calculated (V_g_BPF Magnitude Calculation), and the calculated magnitude level (V_g_m) is compared with a reference level (V_g_level). If the magnitude level (V_g_m) is greater than the reference level (V_g_level), it is determined that no touch fault or grounding fault has occurred, and the system is activated. If the magnitude level (V_g_m) is below the reference level (V_g_level) for a predetermined time (T_s), it is determined that a touch fault or ground fault has occurred, and the CB is shut off for safety reasons.

[0057] Figure 6 is a graph showing the results of fault detection when the fault detection device detects a battery touch fault, but the grid type is LL and has a frequency of 60 Hz, and Figure 7 is a graph showing the results of fault detection when the grid type is LN and has a frequency of 50 Hz. The first voltage V_g has a different value when a fault occurs depending on whether it is connected to the positive or negative terminal, but it can be seen that the magnitude level of the difference BPF (ADC1-ADC2) between the filtered output of the inverting amplifier and the output of the non-inverting amplifier becomes small regardless of the V_g value. In other words, it can be seen that by detecting a touch fault using the difference between the filtered output of the inverting amplifier and the output of the non-inverting amplifier, it is possible to detect a touch fault regardless of the grid type or the location where the touch fault occurs.

[0058] The converter may be a DC-DC converter inside the battery pack, and in this case, the processing unit 130 can detect battery contact or ground fault of the battery pack. As shown in FIG. 8, the battery pack may include a battery and a converter, and the fault detection device can detect contact caused by contact between the cases of both ends of the input terminal connected to the battery of the DC-DC converter inside the battery pack. The output terminal of the battery pack may be connected to the grid via an inverter (PCS), and when a fault is detected, the CB connected to the output terminal of the battery may be opened to cut off the connection between the inverter and the grid. The connection between the battery and the DC-DC converter may also be cut off.

[0059] The converter may be a DC-DC converter connected to a solar power generation module, and in this case, the processing unit 130 can detect contact or ground fault of at least one terminal of both ends of the input terminal of the DC-DC converter to the solar power generation module. As shown in Figure 9, the solar power generation system may include a converter and an inverter, and the fault detection device can detect contact fault caused by contact between both ends of the input terminal of the DC-DC converter connected to the solar power generation module (PV module) and the cases inside the module of the solar power generation system. The output terminal of the solar power generation system may be connected to the grid, and can cut off the connection with the solar power generation module when a fault is detected.

[0060] As described above, by detecting the first voltage using a plurality of resistors and a sensing circuit and comparing it with a reference level using the first voltage, it is possible to detect faults such as contact or ground faults. This can be used to detect contact (dielectric breakdown) faults in battery power supplies of power conversion systems for solar and grid-connected ESS.

[0061] FIG. 10 is a block diagram of a DC-DC converter according to an embodiment of the present invention.

[0062] A DC-DC converter 1000 according to an embodiment of the present invention includes an input terminal 210 connected to a battery or a solar panel, and a fault detection circuit that detects contact or ground fault of at least one terminal of both ends of the input terminal. A detailed description of the fault detection circuit of the DC-DC converter 1000 according to an embodiment of the present invention corresponds to the detailed description of the fault detection device in Figures 1 to 9, so the overlapping description will be briefly given below.

[0063] The DC-DC converter 1000 of the present invention is connected to a battery or a solar power generation panel via an input terminal 210, converts the input power, and outputs the converted power. The DC-DC converter 1000 may be a DC-DC converter included in a battery pack, in which case power is input from the battery, converted, and output, and the output power may be transmitted to a grid via an inverter. Alternatively, conversely, power may be applied from a solar power generation panel or the grid, converted, and then used to charge the battery. The DC-DC converter 1000 may be a DC-DC converter included in a solar power generation module, in which power generated by a solar power generation panel is input, converted, and output, and the output power may be transmitted to a grid via an inverter or used to charge a battery.

[0064] The fault detection circuit detects a contact or ground fault of at least one terminal of an input terminal of a DC-DC converter, and may include a plurality of resistors 110 connected in series between the input terminals of the converter, a sensing circuit 120 measuring a first voltage of one of the nodes between the plurality of resistors, and a processing unit 130 detecting a fault using a change in the first voltage.

[0065] Here, the plurality of resistors may include a first resistor, a second resistor, and a third resistor connected in series from the positive terminal to the negative terminal of the input port 210, a node between the first resistor and the second resistor may be connected to a case of the converter 1100, and the sensing circuit 120 may measure the first voltage at the node between the second resistor and the third resistor. The sensing circuit 120 may include an inverting amplifier and a non-inverting amplifier to which the first voltage is respectively input, and outputs of the inverting amplifier and the non-inverting amplifier may be applied to the processing unit 130.

[0066] The circuit also includes a first low-pass filter that filters the output of the inverting amplifier and a second low-pass filter that filters the output of the non-inverting amplifier, and the output of the inverting amplifier and the output of the non-inverting amplifier may be applied to the processing unit 130 via the first low-pass filter and the second low-pass filter, respectively, and the processing unit 130 may detect a fault using the difference between the output of the inverting amplifier and the output of the non-inverting amplifier.

[0067] The output terminal of the converter is connected to a grid, and the processing unit 130 filters the difference between the output of the inverting amplifier and the output of the non-inverting amplifier using a band-pass filter that filters the frequency band of the grid, and detects a fault by comparing the magnitude level of the filtered difference between the output of the inverting amplifier and the output of the non-inverting amplifier with a reference level. The processing unit 130 may determine that a fault has occurred if the magnitude level of the filtered difference between the output of the inverting amplifier and the output of the non-inverting amplifier is smaller than the reference level for a predetermined period of time or longer. When a fault is detected, the processing unit 130 may disconnect at least one of the input terminal and the output terminal of the converter, thereby protecting the entire system.

[0068] The converter 1000 may be a DC-DC converter inside a battery pack, and the processing unit 130 may detect contact or ground fault of the battery of the battery pack, or the converter 1000 may be a DC-DC converter connected to a solar power generation module, and the processing unit 130 may detect contact or ground fault of at least one terminal of both ends of an input terminal of the DC-DC converter to the solar power generation module.

[0069] FIG. 11 is a block diagram of a battery pack according to one embodiment of the present invention.

[0070] A battery pack 1100 according to an embodiment of the present invention includes a battery 1110, a DC-DC converter 1000 that converts the voltage of the battery 1110, and a fault detection circuit that detects contact or ground fault of the battery 1110. A detailed description of the DC-DC converter 1000 and the fault detection circuit of the battery pack 1100 according to an embodiment of the present invention corresponds to the detailed description of the fault detection device in Figures 1 to 9 and the DC-DC converter in Figure 10, so the overlapping description will be briefly described below.

[0071] The battery pack 1100 of the present invention converts the power of the battery 1110 located inside by the DC-DC converter 1000 and outputs the converted power, and the output power can be transmitted to the grid via an inverter. Alternatively, conversely, power can be applied from a solar panel or the grid, and the applied power can be converted to charge the battery.

[0072] The fault detection circuit detects contact or ground fault of at least one terminal of the battery 1110. The fault detection circuit may include a plurality of resistors 110 connected in series between the two ends of the battery 1110, a sensing circuit 120 measuring a first voltage of one of the nodes between the plurality of resistors, and a processing unit 130 detecting a fault using a change in the first voltage.

[0073] Here, the plurality of resistors may include a first resistor, a second resistor, and a third resistor connected in series in order from the positive terminal to the negative terminal of the input port 210, a node between the first resistor and the second resistor may be connected to a case of the battery pack 1100, and the sensing circuit 120 may measure the first voltage at the node between the second resistor and the third resistor. The sensing circuit 120 may include an inverting amplifier and a non-inverting amplifier to which the first voltage is respectively input, and outputs of the inverting amplifier and the non-inverting amplifier may be applied to the processing unit 130.

[0074] The circuit also includes a first low-pass filter that filters the output of the inverting amplifier and a second low-pass filter that filters the output of the non-inverting amplifier, and the output of the inverting amplifier and the output of the non-inverting amplifier may be applied to the processing unit 130 via the first low-pass filter and the second low-pass filter, respectively, and the processing unit 130 may detect a fault using the difference between the output of the inverting amplifier and the output of the non-inverting amplifier.

[0075] The output terminal of the converter is connected to a grid, and the processing unit 130 filters the difference between the output of the inverting amplifier and the output of the non-inverting amplifier using a band-pass filter that filters the frequency band of the grid, and detects a fault by comparing the magnitude level of the difference between the filtered output of the inverting amplifier and the output of the non-inverting amplifier with a reference level. The processing unit 130 may determine that a fault has occurred if the magnitude level of the difference between the filtered output of the inverting amplifier and the output of the non-inverting amplifier is lower than the reference level for a predetermined time or longer. When a fault is detected, the processing unit 130 may shut off a circuit breaker (CB), which is connected to the output terminal of the battery pack 1100 and controls on / off of a connection to the outside, thereby protecting the entire system.

[0076] Fig. 12 is a flowchart of a fault detection method according to an embodiment of the present invention, and Fig. 13 is a flowchart of a fault detection method according to an embodiment of the present invention. Detailed explanations of each step in Fig. 12 and Fig. 13 correspond to the detailed explanations of the fault detection devices in Fig. 1 to Fig. 11, so overlapping explanations will be explained briefly below.

[0077] In order to detect a contact or ground fault of a battery or a solar panel connected to the input terminal of the DC-DC converter, in step S11, a first voltage is sensed from a fault detection circuit connected across the input terminal.

[0078] The fault detection circuit may include a plurality of resistors connected in series between both ends of the battery, a sensing circuit for measuring a first voltage at one of nodes between the plurality of resistors, and a change in the first voltage to detect a fault. The plurality of resistors may include a first resistor, a second resistor, and a third resistor connected in series in order from a positive terminal to a negative terminal of the input terminal, the node between the first resistor and the second resistor being connected to a case of the converter, and the sensing circuit may measure the first voltage at the node between the second resistor and the third resistor.

[0079] Then, in step S12, a magnitude level of the difference between the inverted and non-inverted values ​​of the first voltage is calculated and compared with a reference level to detect the presence or absence of a fault. The sensing circuit includes an inverting amplifier and a non-inverting amplifier to which the first voltage is respectively input, and the presence or absence of a fault can be detected using the outputs of the inverting amplifier and the non-inverting amplifier. Here, the sensing circuit includes a first low-pass filter that filters the output of the inverting amplifier and a second low-pass filter that filters the output of the non-inverting amplifier, and the outputs of the inverting amplifier and the non-inverting amplifier can be applied through the first low-pass filter and the second low-pass filter, respectively, and the fault can be detected using the difference between the outputs of the inverting amplifier and the non-inverting amplifier.

[0080] The output terminal of the converter is connected to a grid, and a difference between the output of the inverting amplifier and the output of the non-inverting amplifier is filtered using a band-pass filter that filters the frequency band of the grid, and a fault can be detected by comparing the magnitude level of the filtered difference between the output of the inverting amplifier and the output of the non-inverting amplifier with a reference level. In this case, if the magnitude level of the filtered difference between the output of the inverting amplifier and the output of the non-inverting amplifier is smaller than the reference level for a predetermined time or longer, it can be determined that a fault has occurred.

[0081] If a fault is detected in step S12, the connection to the outside can be cut off in step S21. When a fault is detected, the CB (Circuit Breaker), which is a circuit breaker that controls the on / off of the connection to the outside, can be cut off to protect the system.

[0082] Meanwhile, embodiments of the present invention may be embodied as computer-readable codes on a computer-readable recording medium, including all types of recording devices that store data that can be read by a computer system.

[0083] Examples of computer-readable recording media include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, etc. Computer-readable recording media can be distributed among computer systems connected via a network, and computer-readable code can be stored and executed in a distributed manner. Functional programs, codes, and code segments for implementing the present invention can be easily construed by programmers skilled in the art to which the present invention pertains.

[0084] Those skilled in the art will understand that the present invention may be embodied in various modified forms without departing from the essential characteristics of the above description. Therefore, the disclosed method should be considered in an illustrative rather than a restrictive sense. The scope of the present invention is defined by the claims, not the foregoing description, and all differences within the scope of the claims should be construed as being within the scope of the present invention.

Claims

1. a plurality of resistors connected in series across the input terminal of the converter; a sensing circuit for measuring a first voltage at one of the nodes between the plurality of resistors; a processing unit that detects a fault using a change in the first voltage.

2. The plurality of resistors a first resistor, a second resistor, and a third resistor connected in series in this order from the positive terminal to the negative terminal of the input terminal; a node between the first resistor and the second resistor is connected to a case of the converter; The fault detection device of claim 1 , wherein the sensing circuit measures the first voltage at a node between the second resistor and the third resistor.

3. The sensing circuit includes: an inverting amplifier and a non-inverting amplifier to which the first voltage is respectively input; The fault detection device according to claim 1 , wherein the output of the inverting amplifier and the output of the non-inverting amplifier are applied to the processing unit.

4. a first low-pass filter for filtering the output of the non-inverting amplifier; a second low-pass filter for filtering the output of the inverting amplifier; 4. The fault detection device according to claim 3, wherein the output of the non-inverting amplifier and the output of the inverting amplifier are applied to the processing unit via the first low-pass filter and the second low-pass filter, respectively.

5. The processing unit 4. The fault detection device according to claim 3, wherein a fault is detected using a difference between the output of said inverting amplifier and the output of said non-inverting amplifier.

6. the output end of the converter is connected to a grid; The processing unit filtering the difference between the output of the inverting amplifier and the output of the non-inverting amplifier using a bandpass filter that filters the frequency band of the grid; 6. The fault detection device according to claim 5, wherein a magnitude level of the difference between the filtered output of the inverting amplifier and the output of the non-inverting amplifier is compared with a reference level to detect a fault.

7. The processing unit 7. The fault detection device according to claim 6, wherein it is determined that a fault has occurred when the magnitude level of the difference between the filtered output of the inverting amplifier and the output of the non-inverting amplifier is smaller than the reference level for a predetermined time or longer.

8. The processing unit 2. The fault detection device according to claim 1, wherein upon detection of a fault, at least one of the input and output terminals of the converter is disconnected.

9. the converter is a DC-DC converter inside a battery pack; The processing unit The fault detection device according to claim 1 , wherein the fault detection device detects a contact or a ground fault of the battery of the battery pack.

10. the converter is a DC-DC converter connected to a photovoltaic power generation module, The processing unit 2. The fault detection device according to claim 1, wherein the fault detection device detects contact or ground fault of at least one terminal of both ends of the photovoltaic power generation module input terminal of the DC-DC converter.

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