Resistance measuring device

Abstract

A resistance measuring apparatus according to one embodiment of the present invention comprises: a first resistor unit connected between a (+) terminal of a first channel and ground; a second resistor unit connected between the (+) terminal of the second channel and ground; a third resistor unit connected between (-) terminals of the first and second channels and ground; a voltage measurement unit that measures a voltage applied between both ends of the first resistor unit, both ends of the second resistor unit, or both ends of the third resistor unit; and a processing unit that calculates an insulation resistance using resistance values of the first resistor unit, the second resistor unit, and the third resistor unit and a voltage value of one of the first resistor unit, the second resistor unit, or the third resistor unit, in which the first channel and the second channel are connected in parallel.

Description

Technical Field

[0001] The present disclosure relates to a resistance measurement device, and more particularly to a resistance measurement device, a resistance measurement circuit, and a resistance measurement method for measuring the insulation resistance of channels connected in parallel. Background Art

[0002] With the increasing awareness of environmental protection in recent years, there has been a growing interest in methods of generating electricity without emitting pollutants such as carbon dioxide. In particular, due to technological advancements that have made the development and installation costs cheaper, power generation systems using solar energy are becoming increasingly common.

[0003] These solar power generation systems include a plurality of photovoltaic modules in which a plurality of photovoltaic cell units are assembled. The DC power generated from the plurality of photovoltaic modules is converted into AC power by an inverter, and the AC power can be directly used for household and industrial facilities.

[0004] On the other hand, in the case of photovoltaic power generation, there is inevitably a power generation blank period when power generation cannot be sufficiently performed due to weather changes or the absence of sunlight at night. Therefore, in order to compensate for these drawbacks, a photovoltaic power generation system must be provided with a battery to ensure stable power supply.

[0005] A household photovoltaic system including a battery can be configured as shown in Figure 1 When a battery, a battery management system (BMS), and a DC-DC converter are provided inside the battery pack. At this time, when a plurality of photovoltaic power generation panels or a plurality of battery packs are used, it is necessary to maintain the insulation of the plurality of channels connecting these photovoltaic power generation panels or battery packs to achieve stable system operation. A technology capable of accurately and quickly detecting whether insulation is maintained is required. Summary of the Invention

Technical Problem

[0006] The technical problem to be solved by the present disclosure is to provide a resistance measurement device, a resistance measurement circuit, and a resistance measurement method for measuring the insulation resistance of channels connected in parallel.

Solution to the Problem

[0007] To solve the technical problem, a resistance measurement device according to an embodiment of the present disclosure includes: a first resistor unit connected between the (+) terminal of the first channel and the ground; a second resistor unit connected between the (+) terminal of the second channel and the ground; a third resistor unit connected between the (-) terminal of the first channel and the (-) terminal of the second channel and the ground; a voltage measurement unit configured to measure the voltage applied across the two ends of the first resistor unit, the second resistor unit, or the third resistor unit; and a processing unit configured to calculate the insulation resistance by using the resistance values of the first resistor unit, the second resistor unit, and the third resistor unit and the voltage value of one of the first resistor unit, the second resistor unit, and the third resistor unit, wherein the first channel and the second channel are connected in parallel.

[0008] In addition, the processing unit may be configured to: measure the voltages applied across the two ends of the first resistor unit, the second resistor unit, and the third resistor unit in a first state where the first resistor unit has a first resistance value, the second resistor unit has a second resistance value, and the third resistor unit has a third resistance value, measure the voltages applied across the two ends of the first resistor unit, the second resistor unit, or the third resistor unit in a second state where the first resistor unit has a fourth resistance value, the second resistor unit has a fifth resistance value, or the third resistor unit has a sixth resistance value, and calculate the insulation resistance by using the voltage difference between the voltages applied across the two ends of the first resistor unit, the second resistor unit, or the third resistor unit in the first state and the second state.

[0009] In addition, the processing unit may be configured to: change the resistance value of the resistor unit having the maximum voltage across the two ends measured in the first state, and calculate the insulation resistance by using the voltage difference, the voltage of the resistor unit whose resistance value has been changed in the first state, the first resistance value, the second resistance value, the third resistance value, and the changed resistance value.

[0010] In addition, the processing unit may be configured to: compare the insulation resistance with a reference insulation resistance to determine whether the insulation resistance is within a normal range.

[0011] In addition, the insulation resistance may be the total parallel insulation resistance of the first channel and the second channel.

[0012] In addition, the first resistor unit may include a first resistor, a second resistor connected in parallel to the first resistor, and a first switch connected in series to the second resistor. The second resistor unit may include a third resistor, a fourth resistor connected in parallel to the third resistor, and a second switch connected in series to the fourth resistor. And the third resistor unit may include a fifth resistor, a sixth resistor connected in parallel to the fifth resistor, and a third switch connected in series to the sixth resistor.

[0013] In addition, the second resistor, the fourth resistor, and the sixth resistor may have the same resistance value.

[0014] In addition, the resistance measuring device may include a fourth switch configured to connect the first resistor unit, the second resistor unit, and the third resistor unit to ground.

[0015] To solve the technical problem, a resistance measuring circuit according to an embodiment of the present disclosure includes: a plurality of (+) terminal resistor units connected between the (+) terminal of each of a plurality of channels and ground; a (-) terminal resistor unit connected between the node to which the (-) terminals of the plurality of channels are connected and ground; and a voltage measuring unit configured to measure the voltage applied across at least one of the plurality of (+) terminal resistor units or across the (-) terminal resistor unit, wherein the plurality of channels are connected in parallel.

[0016] In addition, the resistance measuring device may include a processing unit configured to calculate the total parallel insulation resistance of the plurality of channels by using the resistance value of each of the plurality of (+) terminal resistor units, the resistance value of the (-) terminal resistor unit, and one of the voltage values of at least one of the (+) terminal resistor units and the (-) terminal resistor unit.

[0017] In addition, the processing unit may change the resistance value of the resistor unit across which the voltage with the maximum measured value in the first state is applied, and may calculate the total parallel insulation resistance by using the voltage difference measured in the second state when the resistance value is changed, the voltage of the resistor unit whose resistance value is changed in the first state, the resistance value of each of the plurality of (+) terminal resistor units in the first state, the resistance value of the (-) terminal resistor unit in the first state, and the changed resistance value.

[0018] To solve the technical problem, embodiments of the present disclosure include: turning on a switch that connects a resistance measurement circuit connected to a plurality of channels connected in parallel to ground; measuring the voltage between the (+) terminal of each of the plurality of channels and ground and the voltage between the node to which the (-) terminals of the plurality of channels are connected and ground in a first state; changing the resistance value of one of the plurality of (+) terminal resistor units between the (+) terminal of the plurality of channels and ground and the (-) terminal resistor unit between the node to which the (-) terminals of the plurality of channels are connected and ground; and calculating the total parallel insulation resistance of the plurality of channels by using the resistance value of each of the plurality of (+) terminal resistor units, the resistance value of the (-) terminal resistor unit, and one voltage value among the voltage values of at least one of the (+) terminal resistor unit and the (-) terminal resistor unit.

[0019] In addition, changing the resistance value may include changing the resistance value by connecting a resistor having a preset resistance value in parallel to the resistor unit having the maximum measured value across both ends in the first state.

[0020] In addition, calculating the total parallel insulation resistance of the plurality of channels may include: calculating the total parallel insulation resistance by using the voltage value of the resistor unit whose resistance value has changed in the second state in which the resistance value has been changed, the resistance value of the resistor unit whose resistance value has changed in the first state, the resistance value of each of the plurality of (+) terminal resistor units in the first state, the resistance value of the (-) terminal resistor unit in the first state, and the resistance value of the resistor connected in parallel.

[0021] In addition, it may include comparing the total parallel insulation resistance with a reference insulation resistance to determine whether the total parallel insulation resistance is within a normal range.

Advantages of the present invention

[0022] According to embodiments of the present disclosure, even when a plurality of channels are connected in parallel for a photovoltaic power generation panel array or a battery pack, the total parallel insulation resistance can be calculated, thereby detecting single or multiple fault states. In addition, it can be applied under the condition that a single channel or a plurality of channels are connected in parallel, regardless of the number of channels. It can be used not only for photovoltaic power generation systems but also for measuring the insulation resistance of batteries. Therefore, it has excellent scalability. In addition, the insulation resistance can be measured under parallel connection conditions by using a simple measurement circuit, the number of components for relays or switch elements can be reduced, and a separate power source for initially driving the relay or switch is not required. In other words, an accurate insulation resistance value can be calculated only through a simple sequence, which helps to ensure the product competitiveness. Description of the Drawings

[0023] Figure 1 is a diagram for describing a photovoltaic power generation system to which a resistance measurement device according to an embodiment of the present disclosure is applied.

[0024] Figure 2 is a block diagram of a resistance measurement device according to an embodiment of the present disclosure.

[0025] Figures 3 to 5 is a diagram for describing a resistance measurement device according to an embodiment of the present disclosure.

[0026] Figure 6 is a block diagram of a resistance measurement circuit according to an embodiment of the present disclosure.

[0027] Figure 7 is a flowchart of a resistance measurement method according to an embodiment of the present disclosure.

[0028] Figure 8 is a flowchart of a resistance measurement method according to an embodiment of the present disclosure. Detailed implementation manners

[0029] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0030] However, the technical concept of the present disclosure is not limited to some embodiments described herein, but can be implemented in various different forms, and one or more components in the embodiments can be selectively combined or replaced within the scope of the technical concept of the present disclosure for use.

[0031] In addition, unless otherwise defined, the terms (including technical terms and scientific terms) used in the embodiments of the present disclosure have the same meanings as those commonly understood by those of ordinary skill in the art. The meanings of common terms (such as terms defined in a dictionary) can be interpreted in consideration of the context of the related art.

[0032] In addition, the terms used in the embodiments of the present disclosure are for the purpose of describing the embodiments and are not intended to limit the present disclosure.

[0033] In this specification, unless otherwise specifically stated in a phrase, the singular form may also include the plural form, and the expression “at least one (or one or more) of A, B, and C” may refer to one or more of all combinations including A, B, and C.

[0034] In addition, when describing components of the embodiments of the present disclosure, terms such as first, second, A, B, (A), (B), etc. may be used. These terms are only intended to distinguish the components from each other and are not intended to limit the nature, order, or sequence of the components.

[0035] When a component is described as "connected", "coupled", or "linked" to another component, it can include not only the case where the component is directly "connected", "coupled", or "linked" to the other component, but also the case where the component is "connected", "coupled", or "linked" through other components between the component and the other component.

[0036] In addition, when a component is described as formed or disposed "on" or "under" each component, the terms "on" or "under" include not only the case where the 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. In addition, when expressed as "on" or "under", based on a component, it can include not only the meaning of the upward direction, but also the meaning of the downward direction.

[0037] Modifications of this embodiment can together include some configurations of the corresponding embodiment and some configurations of other embodiments. That is, the modification can include one embodiment among various embodiments, but some components can be omitted and some components of the corresponding other embodiments can be included. Or, vice versa. The features, structures, effects, etc. to be described in the embodiments are included in at least one embodiment and are not necessarily limited to only one embodiment. In addition, the features, structures, effects, etc. described in each embodiment can be combined or modified by those of ordinary skill in the art and implemented in other embodiments. Therefore, the description of these combinations and modifications should be construed as falling within the scope of the embodiments.

[0038] Figure 1 It is a diagram for describing a photovoltaic power generation system to which a resistance measurement device according to an embodiment of the present disclosure is applied.

[0039] As Figure 1 shown, the photovoltaic power generation system can include a photovoltaic power source 10, an inverter 20, a battery pack 30, and a load 50. However, those of ordinary skill in the art will understand that in addition to Figure 1 the components shown in Figure 1 , other general components can also be included in the photovoltaic power generation system. For example, the photovoltaic power generation system can also include a power grid 40. Alternatively, those of ordinary skill in the art will understand that in other embodiments, some of the components shown in

[0040] The photovoltaic power source 10 may include a plurality of photovoltaic modules in which photovoltaic cell units are assembled, and the photovoltaic cell units in which a P-type semiconductor and an N-type semiconductor are combined generate electricity by using light. Specifically, when light irradiates the photovoltaic cell units, electrons and holes are generated therein. The generated charges move toward the P electrode and the N electrode, and this action generates a potential difference between the P electrode and the N electrode. At this time, when a load is connected to the photovoltaic cell units, current flows. Here, the photovoltaic cell unit refers to the smallest unit for generating electricity, and the photovoltaic cell units are assembled together to form a battery module. The battery modules may form an array connected in series / parallel to form the photovoltaic power source 10.

[0041] The inverter 20 may convert the direct current (DC) power generated from the photovoltaic power source 10 through the photovoltaic effect into alternating current (AC) power, thereby supplying power to the power grid 40 or the load 50. Here, the power grid 40 may refer to a power grid for transmitting and distributing the power generated from the photovoltaic power generation system. On the other hand, due to time factors such as sunrise and sunset or external factors such as weather, the amount of power generated from the photovoltaic power source 10 constantly changes. Therefore, the inverter 20 controls the voltage generated from the photovoltaic power source 10 to find the maximum power and supply the maximum power to the power grid 40. At this time, when the power used to operate the inverter is lower than the output power of the inverter, the inverter 20 may consume power from the power grid 40 in reverse. Of course, in this case, the inverter may block the power flowing into the power grid 40 to prevent power reversal. Therefore, various optimizer control methods are applied to the photovoltaic power generation system so that the operation of the above-mentioned inverter 20 can be performed more effectively and the maximum power can be extracted from the photovoltaic power source 10. Typical maximum power point tracking (MPP) methods for the photovoltaic power source 10 include the perturbation and observation (PO) method, the incremental conductance (IC) control method, and the constant voltage (CV) control method. Here, the PO method is a method of periodically measuring the voltage and current of the photovoltaic power source 10 to calculate the power, and then tracking the MPP by using the power value. The IC control method is a method of measuring the voltage and current generated from the photovoltaic power source 10 and performing control so that the power change rate becomes '0' for the change in the operating point of the terminal voltage of the array. The CV control method is a method of controlling the photovoltaic power source 10 to a constant reference voltage (REF V) regardless of the operating voltage or power of the array. According to each optimizer control method, the power source input from the photovoltaic power source 10 to the inverter may operate as a voltage source or a current source.

[0042] The load 50 may refer to a product using electric power in real life. For example, the inverter 20 can obtain AC power with a desired voltage and frequency through an appropriate conversion method, switching element, or control circuit, so as to supply power to household appliances in ordinary households or mechanical products in industrial facilities. Additionally, in the case of photovoltaic power generation, when power generation is insufficient due to weather changes or no sunlight at night, there will inevitably be a power generation blank period. Therefore, to make up for these deficiencies, a photovoltaic power generation system must be provided with a battery to ensure 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 include a lithium-ion battery or a nickel-metal hydride battery, but the present disclosure is not necessarily limited to this configuration, and the battery may refer to a battery that can be used semi-permanently through charging. The DC-DC converter is a device that converts the DC power generated by the photovoltaic power source 10 into DC power suitable for the battery, or converts the battery power into power suitable for the power grid. Generally, the DC-DC converter can perform power conversion by converting DC power into AC power and then converting the AC power back into DC power. The BMS can provide a function of protecting against misuse of the battery cells constituting the battery, as well as functions of balancing between the unit cells, measuring the state of charge (SOC), maintaining the temperature, or monitoring the system. Therefore, based on a sensor for measuring the state of the battery cells and a function of receiving the measurement values of the sensor and transmitting the measurement values to the control system of the application product, a circuit can be constructed and controlled to generate an abnormal signal and block or disconnect the power circuit between the battery cells when the temperature and charge state of the system exceed the set values.

[0044] Figure 2 is a block diagram of a resistance measurement device according to an embodiment of the present disclosure, and Figures 3 to 5 is a diagram for describing a resistance measurement device according to an embodiment of the present disclosure.

[0045] The resistance measurement device according to an embodiment of the present disclosure detects the insulation resistance of one or more channels. Here, one or more photovoltaic panels or battery packs can be connected to the channels for which the insulation resistance is to be detected. By detecting the insulation resistance, it can be determined whether the insulation is maintained in the power output from the photovoltaic panel or the battery pack. The photovoltaic panel or battery pack determined to be safe due to maintaining insulation can be connected to a device or circuit intended to supply its power output. That is, the insulation resistance device according to an embodiment of the present disclosure can be used to check whether the insulation resistance remains higher than a reference value before connecting the photovoltaic panel or the battery pack. Here, it is obvious that the device for measuring the insulation resistance connected to the channel can include various devices that require insulation, as well as the photovoltaic panel or the battery pack.

[0046] A resistance measuring device according to an embodiment of the present disclosure can measure the insulation resistance of multiple channels. The multiple channels can be connected in parallel. When the multiple channels are connected in parallel, the safety can be determined by measuring the insulation resistance of the connected channels. Since the insulation resistance can be measured quickly and accurately even when the number of channels connected in parallel increases, the scalability is high. Hereinafter, an embodiment in which two channels are connected in parallel will be described. Obviously, the present disclosure can be applied to one channel or three or more channels.

[0047] A resistance measuring device according to an embodiment of the present disclosure may include a first resistor unit 130, a second resistor unit 140, a third resistor unit 150, a voltage measuring unit 170, and a processing unit 180, and may include one or more switches and one or more memories.

[0048] The first channel 110 and the second channel 120 are connected in parallel, and a photovoltaic power generation panel array or a battery pack may be connected to the first channel 110 and the second channel 120. To measure the insulation resistance, before the power supplied through the first channel 110 and the second channel 120 is connected to the device to be powered, the first resistor unit 130 is connected between the (+) terminal of the first channel 110 and the ground 160, the second resistor unit 140 is connected between the (+) terminal of the second channel 120 and the ground 160, and the third resistor unit 150 is connected between the (-) terminals of the first channel 110 and the second channel 120 and the ground 160. The first resistor unit 130 and the second resistor unit 140 are respectively used to measure the (+) terminal voltage of the channel, while the third resistor unit 150 can be used to measure the (-) terminal voltage of the entire channel.

[0049] The first resistor unit 130 includes a first resistor 131, a second resistor 132 connected in parallel to the first resistor 131, and a first switch 133 connected in series to the second resistor 132. In the first resistor unit 130, when the first switch 133 is off, only the first resistor 131 is connected, and when the first switch 133 is on, the first resistor 131 and the second resistor 132 are connected in parallel. Here, the first resistor 131 may have a first resistance value, and the first resistor 131 and the second resistor 132 connected in parallel may have a fourth resistance value. When connected in parallel, the resistance value decreases, so the fourth resistance value may be less than the first resistance value. The resistance value of the second resistor 132 may be the same as the first resistance value. Alternatively, it is obvious that the resistance value of the second resistor 132 may be greater than or less than the first resistance value.

[0050] The second resistor unit 140 includes a third resistor 141, a fourth resistor 142 connected in parallel to the third resistor 141, and a second switch 143 connected in series to the fourth resistor 142. In the second resistor unit 140, when the second switch 143 is off, only the third resistor 141 is connected, and when the second switch 143 is on, the third resistor 141 and the fourth resistor 142 are connected in parallel. Here, the third resistor 141 may have a second resistance value, and the third resistor 141 and the fourth resistor 142 connected in parallel may have a fifth resistance value. When connected in parallel, the resistance value decreases, so the fifth resistance value may be less than the second resistance value. The resistance value of the fourth resistor 142 may be the same as the second resistance value. Alternatively, it is obvious that the resistance value of the fourth resistor 142 may be greater than or less than the second resistance value.

[0051] The third resistor unit 150 includes a fifth resistor 151, a sixth resistor 152 connected in parallel to the fifth resistor 151, and a third switch 153 connected in series to the sixth resistor 152. In the third resistor unit 150, when the third switch 153 is off, only the fifth resistor 151 is connected, and when the third switch 153 is on, the fifth resistor 151 and the sixth resistor 152 are connected in parallel. Here, the fifth resistor 151 may have a third resistance value, and the fifth resistor 151 and the sixth resistor 152 connected in parallel may have a sixth resistance value. When connected in parallel, the resistance value decreases, so the sixth resistance value may be less than the third resistance value. The resistance value of the sixth resistor 152 may be the same as the third resistance value. Alternatively, it is obvious that the resistance value of the sixth resistor 152 may be greater than or less than the third resistance value.

[0052] Here, the second resistor, the fourth resistor, and the sixth resistor may have the same resistance value. When the switches in each resistor unit are on and two resistors are connected in parallel, the resistance values of the additional resistors may be the same as each other. In this way, even when the resistance value of any resistor unit changes, the values of the additional resistors used to calculate the resistance value remain the same, making it easier to measure the insulation resistance.

[0053] It may include a fourth switch 161 that connects the first resistor unit 130, the second resistor unit 140, and the third resistor unit 150 to the ground 160. The fourth switch 161 that connects the corresponding resistor unit to the ground 160 can be turned on to measure the insulation resistance. That is, when connecting the initial channel that requires insulation resistance measurement, the fourth switch 161 can be turned on to connect the first resistor unit 130, the second resistor unit 140, and the third resistor unit 150 to the ground 160. When the fourth switch 161 is turned off, the connection between the first resistor unit 130, the second resistor unit 140, and the third resistor unit 150 and the ground 160 is cut off, so the power supply circuit is not affected.

[0054] As Figure 4 shown, the first resistor unit 130 may include a first resistor R_P1, a second resistor R_S, and a first switch S1, and may be connected between the V_IN1(+) terminal of the first channel 110 and the ground PE or FG. The second resistor unit 140 may include a third resistor R_P2, a fourth resistor R_S, and a second switch S2, and may be connected between the V_IN2(+) terminal of the second channel 120 and the ground PE or FG. The third resistor unit 150 may include a fifth resistor R_N, a sixth resistor R_S, and a third switch S_N, and may be connected between the V_IN1(-) terminal of the first channel 110 and the V_IN1(-) terminal of the second channel 120 and the ground PE or FG.

[0055] The ground 160 may be a protective earth (PE) or a frame ground (FG). Here, the PE may be connected to the ground GND or to a safety conductor. The FG is the position with the lowest potential of the device and may be connected to the housing of the device. For example, it may be grounded by connecting to the outer shell of the battery pack (i.e., the chassis of the battery pack). The first channel 110, the second channel 120, and the ground 160 are designed to be insulated from each other, so an insulation resistance is formed between the first channel 110, the second channel 120, and the ground 160.

[0056] The first switch 133, the second switch 143, the third switch 153, and the fourth switch 161 may include various types of switching elements such as relays and semiconductor switching elements (MOSFETs).

[0057] The voltage measurement unit 170 measures the voltage of the first resistor unit 130, the second resistor unit 140, or the third resistor unit 150. The voltage measurement unit 170 may measure the voltage applied across the two ends of the first resistor unit 130, across the two ends of the second resistor unit 140, or across the two ends of the third resistor unit 150. The voltage measured by the voltage measurement unit 170 may be stored in the memory.

[0058] The processing unit 180 calculates the insulation resistance by using the resistance values of the first resistor unit 130, the second resistor unit 140, and the third resistor unit 150 and one of the voltage values of the first resistor unit 130, the second resistor unit 140, and the third resistor unit 150. In order to measure the insulation resistance formed between the first channel 110 and the second channel 120 and the ground 160, the processing unit 180 calculates the insulation resistance by using the resistance values and voltage values of each resistor unit. Here, the insulation resistance may be the total parallel insulation resistance of the first channel 110 and the second channel 120. As described above, the insulation resistance is formed between the first channel 110 and the second channel 120 and the ground 160. At this time, the insulation resistance may be formed as the insulation resistance between the (+) terminal of the first channel 110 and the ground 160, the insulation resistance between the (-) terminal of the first channel 110 and the ground 160, the insulation resistance between the (+) terminal of the second channel 120 and the ground 160, and the insulation resistance between the (-) terminal of the second channel 120 and the ground 160.

[0059] As Figure 4 shown, the insulation resistance may be formed as the insulation resistance R_P,EX1 between the V_IN1(+) terminal of the first channel 110 and the ground, the insulation resistance R_N,EX1 between the V_IN1(-) terminal of the first channel 110 and the ground, the insulation resistance R_P,EX2 between the V_IN2(+) terminal of the second channel 120 and the ground, and the insulation resistance R_N,EX2 between the V_IN2(-) terminal of the second channel 120 and the ground.

[0060] At this time, all insulation resistances must be maintained higher than the reference insulation resistance. The reference insulation resistance is the minimum insulation resistance that must be maintained for safety. In the case where even one of the insulation resistances is lower than the reference insulation resistance, it is determined that a failure such as insulation breakdown has occurred, and for safety purposes, the operation of the system needs to be stopped. The processing unit 180 calculates the insulation resistance by using the resistance values and voltage values of each resistor unit to quickly and accurately determine the insulation resistance.

[0061] The above four insulation resistances are formed in a parallel connection. Thus, by calculating the total parallel insulation resistance, it is possible to check whether the insulation is well maintained. When multiple resistors are connected in parallel, the total parallel resistance is less than the minimum resistance value of the corresponding resistors connected in parallel. By utilizing this, the total parallel insulation resistance can be calculated, and it can be determined whether the calculated total parallel insulation resistance is higher than the reference insulation resistance. Thus, it is possible to quickly determine whether the insulation is maintained without calculating the individual insulation resistances. When the total parallel insulation resistance is higher than the reference insulation resistance, it means that the individual insulation resistances are also higher than the reference insulation resistance, so it can be determined that it is operating normally.

[0062] To calculate the total parallel insulation resistance, the processing unit 180 can measure the resistance values and voltage values in two states, and calculate the insulation resistance by applying the voltage division formula in each state.

[0063] First, the processing unit 180 can measure the voltages applied across the two ends of the first resistor unit 130, the second resistor unit 140, and the third resistor unit 150 in a first state where the first resistor unit 130 has a first resistance value, the second resistor unit 140 has a second resistance value, and the third resistor unit 150 has a third resistance value.

[0064] The first state is a state in which the fourth switch 161 is turned on so that the first resistor unit 130, the second resistor unit 140, and the third resistor unit 150 are connected to the ground, while the first switch 133, the second switch 143, and the third switch 153 are turned off so that the first resistor unit 130 has a first resistance value, the second resistor unit 140 has a second resistance value, and the third resistor unit 150 has a third resistance value. In the first state, the voltages applied across the two ends of the first resistor unit 130, the second resistor unit 140, and the third resistor unit 150 are measured.

[0065] Thereafter, in a second state where the first resistor unit 130 has a fourth resistance value, the second resistor unit 140 has a fifth resistance value, or the third resistor unit 150 has a sixth resistance value, the voltages applied across the two ends of the first resistor unit 130, the second resistor unit 140, or the third resistor unit 150 are measured.

[0066] By changing the resistance value of at least one of the first resistor unit 130, the second resistor unit 140, and the third resistor unit 150, the state is changed to a second state different from the first state. In the second state, the voltages applied across the two ends of the first resistor unit 130, the second resistor unit 140, or the third resistor unit 150 can be measured.

[0067] At this time, the insulation resistance can be calculated by using the voltage difference between the voltages applied across the two ends of the first resistor unit 130, the second resistor unit 140, or the third resistor unit 150 in the first state and the second state. The total parallel insulation resistance can be calculated by using the corresponding resistance values and voltage values in the first state and the second state, which are different states.

[0068] When changing to the second state, the processing unit 180 can change the resistance value of the resistor unit with the maximum magnitude of the voltage measured across its two ends in the first state, and can calculate the insulation resistance by using the voltage difference, the voltage of the resistor unit whose resistance value has changed in the first state, the first resistance value, the second resistance value, the third resistance value, and the changed resistance value. By only changing the resistance value of the resistor unit with the maximum voltage measured across its two ends in the first state, fast calculation can be performed, and the voltage difference can be increased by changing the value with a large voltage magnitude. Therefore, the error in calculating the insulation resistance can be reduced.

[0069] The processing unit 180 can measure the insulation resistance in the same way as Figure 5 In the first step, the switches or relays connecting the first resistor unit 130, the second resistor unit 140, and the third resistor unit 150 to the ground PE or FG are changed from the open state to the closed state (S1). In the first state, the positive voltages V_P1 and V_P2 and the negative voltage V_N of each channel are measured (S2). The measured values V_P1_0, V_P2_0, and V_N_0 are stored (S3). By comparing the corresponding measured voltages, the highest voltage is selected from the measured voltages (S4), and the switch of the channel for which the corresponding voltage has been measured is changed from the open state to the closed state (S5). Thereafter, again in the second state, the positive voltages V_P1 and V_P2 and the negative voltage V_N of each channel are measured (S6), and the measured values V_P1_1, V_P2_1, and V_N_1 are stored (S7). The difference V between the voltages measured in the first state and the second state is calculated (S8). Here, V can be calculated as follows.

[0070] V = V_P1_1 - V_P1_0

[0071] V = V_P2_1 - V_P2_0

[0072] V = V_N_0 - V_N_1

[0073] Thereafter, the total parallel resistance value R_Iso of the insulation resistor is calculated by using the resistance value of the measurement circuit, the initially measured voltage values VP1_0, VP2_0, and VN_0, and V (S9). The total parallel resistance value can be used to determine the insulation resistance result of the PV array or battery pack connected to the channel. That is, in the case of a failure due to insulation breakdown, it can be detected.

[0074] The total parallel resistance value R_Iso can be calculated by using the resistance values and voltage values in the first state and the second state. In the first state and the second state, the difference in the equation V = V_P1_1 - V_P1_0 occurs at the node between the first resistor unit 130, the second resistor unit 140, and the third resistor unit 150, and the total parallel resistance value R_Iso can be calculated based on the difference in the equations in the first state and the second state. The resulting total parallel resistance value R_Iso is equal to the total parallel resistance value obtained by multiplying the first resistor 131, the second resistor 132, the third resistor 141, the fifth resistor 151, and the second resistor 132 by the ratio of V according to the voltage of the resistor unit with the maximum voltage in the first state. That is, the total parallel insulation resistance can be calculated by using the first resistor 131, the second resistor 132, the third resistor 141, the fifth resistor 151, and the voltages in the first state and the second state of the resistor unit with the maximum voltage in the first state.

[0075] The processing unit 180 can compare the calculated insulation resistance with a reference insulation resistance to determine whether the insulation resistance is within the normal range. The calculated insulation resistance can be the total parallel insulation resistance, and when the total parallel insulation resistance is greater than the reference insulation resistance, it can be confirmed that each insulation resistance is greater than the reference insulation resistance, and the insulation remains within the normal range.

[0076] Figure 6 is a block diagram of a resistance measurement circuit according to an embodiment of the present disclosure. According to an embodiment of the present disclosure Figure 6 The detailed description of the resistance measurement circuit corresponding to Figures 1 to 5 the detailed description of the resistance measurement device, so any redundant description thereof is omitted.

[0077] The resistance measurement circuit according to an embodiment of the present disclosure includes a plurality of (+) terminal resistor units 230 connected between the (+) terminals of a plurality of channels 210 and the ground 260, a single (-) terminal resistor unit 250 connected between the node to which the (-) terminals of the plurality of channels are connected and the ground 260; and a voltage measurement unit 270 that measures the voltage applied across at least one of the plurality of (+) terminal resistor units 230 or the (-) terminal resistor unit 250. The plurality of channels 210 are connected in parallel.

[0078] Here, a resistance measurement circuit according to an embodiment of the present disclosure includes a processing unit 280 that calculates the total parallel insulation resistance of a plurality of channels by using the resistance value of each of a plurality of (+) terminal resistor units, the resistance value of a (-) terminal resistor unit, and one of the voltage values of at least one of the (+) terminal resistor units and the (-) terminal resistor unit.

[0079] In addition, the processing unit 280 may change the resistance value of the resistor unit across which the voltage with the maximum measured value in the first state is applied, and may calculate the total parallel insulation resistance by using the voltage difference measured in the second state in which the resistance value is changed, the voltage of the resistor unit whose resistance value is changed in the first state, the resistance value of each of the plurality of (+) terminal resistor units in the first state, the resistance value of the (-) terminal resistor unit in the first state, and the changed resistance value.

[0080] Figure 7 is a flowchart of a resistance measurement method according to an embodiment of the present disclosure, and Figure 8 is a flowchart of a resistance measurement method according to an embodiment of the present disclosure. Figure 7 and Figure 8 The detailed description of each operation in Figures 1 to 5 corresponds to the detailed description of the resistance measurement device in Figure 6 and the insulation resistance detection circuit in

[0081] Therefore, any redundant description thereof is briefly given below.

[0082] In operation S11, in order to measure the insulation resistance of a plurality of channels, a switch that connects the resistance measurement circuit connected to the plurality of channels connected in parallel to the ground is turned on. Here, the plurality of channels may be connected to a plurality of photovoltaic power generation panel arrays or a plurality of battery packs.

[0083] Thereafter, in operation S14, the total parallel insulation resistance of a plurality of channels is calculated by using the resistance value of each of the plurality of (+) terminal resistor units, the resistance value of the (-) terminal resistor unit, and one of the voltage values of the plurality of (+) terminal resistor units and the (-) terminal resistor unit. Here, the total parallel insulation resistance can be calculated by using the voltage value of the resistor unit whose resistance value has changed in the second state where the resistance value has changed, the voltage value of the resistor unit whose resistance value has changed in the first state, the resistance value of each of the plurality of (+) terminal resistor units in the first state, the resistance value of the (-) terminal resistor unit in the first state, and the resistance value of the resistors connected in parallel.

[0084] In addition, in operation S21, the total parallel insulation resistance can be compared with a reference insulation resistance to determine whether the total parallel insulation resistance is within a normal range.

[0085] On the other hand, embodiments of the present disclosure can be implemented as computer-readable code on a computer-readable recording medium. The computer-readable recording medium includes any type of recording device that stores data readable by a computer system.

[0086] Examples of the computer-readable recording medium include ROM, RAM, CD-ROM, magnetic tape, floppy disk, optical data storage device, etc. In addition, the computer-readable recording medium can be distributed among network-connected computer systems so that the computer-readable code can be stored and executed in a distributed manner. Functional programs, codes, and code segments for implementing the present disclosure can be easily inferred by programmers in the technical field to which the present disclosure pertains.

[0087] Those of ordinary skill in the art will understand that the present disclosure can be implemented in a modified form without departing from its basic features. Therefore, the disclosed method should be considered in an illustrative rather than a restrictive sense. The scope of the present disclosure is indicated in the claims rather than the foregoing description, and all differences within the scope equivalent thereto should be construed as falling within the present disclosure.

Claims

1. A resistance measuring device, comprising: A first resistor unit connected between the positive terminal of the first channel and the ground; A second resistor unit connected between the positive terminal of the second channel and the ground; A third resistor unit connected between the negative terminals of the first channel and the second channel and the ground; A voltage measuring unit configured to measure the voltage applied across the two ends of the first resistor unit, the two ends of the second resistor unit, or the two ends of the third resistor unit; And A processing unit configured to calculate the insulation resistance by using the resistance values of the first resistor unit, the second resistor unit, and the third resistor unit and the voltage value of one of the resistor units among the first resistor unit, the second resistor unit, and the third resistor unit, Wherein, the first channel and the second channel are connected in parallel.

2. The resistance measuring device according to claim 1, wherein, The processing unit is configured to: In a first state where the first resistor unit has a first resistance value, the second resistor unit has a second resistance value, and the third resistor unit has a third resistance value, measure the voltages applied across the two ends of the first resistor unit, the two ends of the second resistor unit, and the two ends of the third resistor unit; In a second state where the first resistor unit has a fourth resistance value, the second resistor unit has a fifth resistance value, or the third resistor unit has a sixth resistance value, measure the voltage applied across the two ends of the first resistor unit, the two ends of the second resistor unit, or the two ends of the third resistor unit; And Calculate the insulation resistance by using the voltage difference between the voltages applied across the two ends of the first resistor unit, the two ends of the second resistor unit, or the two ends of the third resistor unit in the first state and the second state.

3. The resistance measuring device according to claim 2, wherein, The processing unit is configured to: Change the resistance value of the resistor unit with the largest voltage across the two ends measured in the first state; And Calculate the insulation resistance by using the voltage difference, the voltage of the resistor unit whose resistance value has been changed in the first state, the first resistance value, the second resistance value, the third resistance value, and the changed resistance value.

4. The resistance measuring device according to claim 1, wherein, The processing unit compares the insulation resistance with a reference insulation resistance to determine whether the insulation resistance is within a normal range.

5. The resistance measuring device according to claim 1, wherein The insulation resistance is the total parallel insulation resistance of the first channel and the second channel.

6. The resistance measuring device according to claim 1, wherein, The first resistor unit includes a first resistor, a second resistor connected in parallel to the first resistor, and a first switch connected in series to the second resistor, The second resistor unit includes a third resistor, a fourth resistor connected in parallel to the third resistor, and a second switch connected in series to the fourth resistor, The third resistor unit includes a fifth resistor, a sixth resistor connected in parallel to the fifth resistor, and a third switch connected in series to the sixth resistor.

7. The resistance measuring device according to claim 6, wherein, The second resistor, the fourth resistor, and the sixth resistor have the same resistance value.

8. The resistor measurement device according to claim 1, comprising: A fourth switch configured to connect the first resistor unit, the second resistor unit, and the third resistor unit to the ground.

9. A resistor measurement circuit, comprising: A plurality of positive terminal resistor units connected between the positive terminal of each of a plurality of channels and the ground; A negative terminal resistor unit connected between the node to which the negative terminals of the plurality of channels are connected and the ground; And A voltage measurement unit configured to measure the voltage applied between the two ends of at least one of the plurality of positive terminal resistor units or between the two ends of the negative terminal resistor unit, Wherein, the plurality of channels are connected in parallel.

10. The resistor measurement circuit according to claim 9, comprising: A processing unit configured to calculate the total parallel insulation resistance of the plurality of channels by using the resistance value of each of the plurality of positive terminal resistor units, the resistance value of the negative terminal resistor unit, and one of the voltage values of the at least one positive terminal resistor unit and the negative terminal resistor unit.

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