Voltage balancer, driving method thereof, and computer-readable recording medium

Abstract

A voltage balancer, a driving method thereof, and a computer-readable recording medium are provided. The method includes, based on a power supply system being in an off-grid state, sensing a first voltage between two terminals of an inverter, a second voltage between one of the two terminals of the inverter and a neutral point located between the two terminals of the inverter, and a third voltage between the other of the two terminals of the inverter and the neutral point; based on the first voltage, turning on at least one pair of switches among a plurality of switches included in the voltage balancer; based on a result of comparing the second voltage with the third voltage, controlling a duty cycle of each driving switch among the plurality of switches that is not turned on; and driving each driving switch based on the controlled duty cycle.

Description

Technical Field

[0001] This invention relates to a voltage balancer and its driving method, as well as a computer-readable recording medium. Background Technology

[0002] Inverters can perform off-grid functionality. Off-grid functionality refers to the inverter's ability to generate the same voltage as the grid voltage in response to continuous loads generated when the grid voltage fails.

[0003] Some countries use two types of grid voltage, such as 240V and 120V. Therefore, inverters can produce 240V and 120V output voltages to perform off-grid functions in response to all types of grid voltages.

[0004] A split-phase inverter can split a 240V output voltage into two 120V output voltages to respond to both the 240V and 120V grid voltages. Split-phase inverters can be used in conjunction with voltage balancers to address load imbalances.

[0005] Load imbalance refers to a state where the power supplied to each terminal of the inverter is uneven due to the different power consumption of the loads connected to each terminal. When the inverter uses a voltage balancer to respond to load imbalance, current flows to the inductors included in the voltage balancer, causing inductor losses. Therefore, a voltage balancer capable of reducing inductor losses is needed.

[0006] The description of the related technology is technical information known to the inventor or obtained during the process of deriving the inventive concept, and should not be considered as having been disclosed prior to the relevant application. Summary of the Invention

[0007] This disclosure provides a voltage balancer and a driving method thereof. This disclosure can provide a voltage balancer with reduced inductor losses and a method for driving the voltage balancer.

[0008] The problems to be solved by the present invention are not limited to those described above. Other problems and advantages of the present invention not mentioned above can be understood through the following description and will become clearer through embodiments of the present invention. Furthermore, it should be understood that the problems and advantages to be solved by the present invention can be achieved by the means and combinations thereof as defined in the appended claims.

[0009] As a technical means to solve the above-mentioned technical problems, a first aspect of this disclosure provides a method for driving a voltage balancer. The method includes: sensing a first voltage between two terminals of an inverter, a second voltage between one of the two terminals of the inverter and a neutral point located between the two terminals of the inverter, and a third voltage between the other terminal of the inverter and the neutral point, based on the power supply system being in an off-grid state; turning on at least one pair of switches among a plurality of switches included in the voltage balancer based on the first voltage; controlling the duty cycle of each drive switch that is not turned on among the plurality of switches based on the result of comparing the second voltage and the third voltage; and driving each drive switch based on the controlled duty cycle.

[0010] A second aspect of this disclosure provides a voltage balancer including a processor configured to: sense a first voltage between two terminals of an inverter, a second voltage between one of the two terminals of the inverter and a neutral point located between the two terminals of the inverter, and a third voltage between the other terminal of the inverter and the neutral point, based on the power supply system being in an off-grid state; based on the first voltage, turn on at least one pair of switches among a plurality of switches included in the voltage balancer; based on a comparison of the second voltage and the third voltage, control the duty cycle of each drive switch that is not turned on among the plurality of switches; and drive each drive switch based on the controlled duty cycle.

[0011] A third aspect of this disclosure may provide a computer-readable recording medium having a program recorded thereon for executing the method of the first aspect of this disclosure on a computer.

[0012] Other aspects, features, and advantages besides those described above will be apparent from the accompanying drawings, claims, and the following detailed description. Attached Figure Description

[0013] The above and other aspects, features, and advantages of certain embodiments of this disclosure will become more apparent from the following description taken in conjunction with the accompanying drawings, in which: Figure 1 This is a schematic diagram illustrating an example of a power supply system; Figure 2 This is a diagram illustrating a voltage balancer along with an off-grid system according to an embodiment; Figure 3 This is a flowchart of a method for driving a voltage balancer according to an embodiment; Figure 4 This is a diagram illustrating a first voltage, a second voltage, and a third voltage that can be sensed by a voltage balancer according to an embodiment; Figure 5This is a diagram showing the internal circuitry of a voltage balancer according to an embodiment; Figure 6 This is a diagram illustrating a method for performing voltage balancing by a voltage balancer according to an embodiment; Figure 7A and Figure 7B This is a diagram illustrating a method for voltage balancing performed by a voltage balancer when the first voltage is positive, according to an embodiment; and Figure 8A and Figure 8B This is a diagram illustrating a method by which a voltage balancer performs voltage balancing when the first voltage is negative, according to an embodiment. Detailed Implementation

[0014] The advantages and features of the present invention, as well as the methods for achieving these advantages and features, will become clear from the following detailed description of the embodiments in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments presented below, but can be implemented in various modes, and it should be understood that all variations, equivalents, and substitutions without departing from the spirit and scope of the invention are included in the embodiments. The following presented embodiments are provided so that this disclosure will be complete and will fully convey the scope of the invention to those skilled in the art. In the description of the invention, certain detailed explanations of related techniques are omitted where it is thought that they may unnecessarily obscure the gist of the invention.

[0015] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. Unless they have a distinctly different meaning in the context, expressions used in the singular encompass expressions used in the plural. In this application, it should be understood that terms such as “comprising,” “including,” and “having” are intended to indicate the presence of features, numbers, steps, actions, components, parts, or combinations thereof disclosed in the specification, and are not intended to exclude the possibility that one or more other features, numbers, steps, actions, components, parts, or combinations thereof may be present or added.

[0016] Some embodiments of this disclosure can be described based on functional block components and various processing steps. Some or all of these functional blocks can be implemented by any number of hardware and / or software components configured to perform a specific function. For example, the functional blocks of this disclosure can be implemented using one or more microprocessors or circuits for a given function. Furthermore, for example, the functional blocks of this disclosure can be implemented using various programming or scripting languages. Functional blocks can be implemented using algorithms that run on one or more processors. The invention can also employ conventional techniques for electronic configuration, signal processing, and / or data processing. The terms “machinery,” “element,” “unit,” and “configuration” can be used broadly and are not limited to mechanical and physical configurations.

[0017] Furthermore, the connecting lines or connecting components shown in the accompanying drawings illustrate only functional and / or physical or circuit connections. In actual devices, connections between components can be represented by functional connections, physical connections, or circuit connections that can be replaced or added.

[0018] This disclosure will be described in detail below with reference to the accompanying drawings.

[0019] Figure 1 This is a schematic example diagram illustrating a power supply system.

[0020] refer to Figure 1 The power supply system 10 may include photovoltaic modules 11, devices 12, loads 14, and / or power distribution equipment 15. The power supply system 10 may be connected to an external power grid 16.

[0021] At least one photovoltaic module 11 can be installed on the roof or exterior wall of a building and can generate electricity. Multiple photovoltaic modules 11 can be connected to form a photovoltaic module array.

[0022] Photovoltaic module 11 can be connected to device 12. For example, at least one device 12 can be connected to each photovoltaic module 11. For example, if one device 12 is connected to each photovoltaic module 11, the number of devices 12 constituting the power supply system 10 can be the same as the number of photovoltaic modules 11.

[0023] Device 12 may correspond to a power regulation system or power conversion system (PCS) that performs power conversion on the power generated from photovoltaic module 11. For example, device 12 may perform certain conversions on the power generated from photovoltaic module 11 and supply the converted power to other components of power supply system 10 (e.g., grid 16 and / or load 14).

[0024] In some embodiments, device 12 may correspond to a module-level power electronic device (MLPE). For example, device 12 may be an optimizer or a microinverter (MI).

[0025] For example, when device 12 is an optimizer, device 12 can regulate the power generated from photovoltaic module 11 and output that power to an inverter (e.g., a string inverter). The current generated by the inverter's conversion (e.g., from direct current (DC) to alternating current (AC)) can be output to grid 16 or load 14.

[0026] For example, when device 12 is an MI, device 12 can convert the power generated from photovoltaic module 11 (e.g., from DC to AC). The current converted by device 12 can be output to grid 16 or load 14.

[0027] As needed, the power supply system 10 may also include a combiner 13. At least some of the devices 12 may be connected to the power distribution equipment 15 via the combiner 13. For example, power outputs from multiple devices 12 may be combined into a single output by the combiner 13 and provided to the power distribution equipment 15.

[0028] Device 12 and power distribution equipment 15 can be connected to a power path excluding combiner 13. At least one device 12 can be connected to power distribution equipment 15 via a power path excluding combiner 13, and at least one other device 12 can be connected to power distribution equipment 15 via combiner 13.

[0029] The combiner 13 can control the voltage, current and / or power output from the device 12 according to the power supply status of the photovoltaic module 11, the device 12 and / or the power grid 16, and can set its operation mode to diagnostic mode, operation mode, etc.

[0030] In some embodiments, the combiner 13 may include an energy management system (EMS) that controls the operation of the combiner 13. The EMS can control the voltage, current and / or power supplied to or output from the combiner 13 according to the power supply status of the photovoltaic module 11, the device 12 and / or the power grid 16, and can set the operating mode of the combiner 13 to a diagnostic mode, an operating mode, etc.

[0031] Load 14 can refer to an object installed in an electricity consumer such as a residence, commercial facility, or factory, and operates by receiving at least one of the energy generated by photovoltaic module 11, energy stored in energy storage system 17, and energy supplied from the power grid 16. For example, when the electricity consumer being supplied with electricity is a residence, load 14 may include household appliances such as a washing machine, refrigerator, or television (TV).

[0032] The power grid 16 may include infrastructure systems for power generation, transmission, and distribution. For example, the power grid 16 may include infrastructure systems such as power plants, substations, and power lines. The power grid 16 may transmit electrical energy generated from power plants to the power supply system 10, or transmit surplus electricity generated in the power supply system 10 to the outside of the power supply system 10.

[0033] For example, commercial electricity transmitted from the power grid 16 via utility poles can be supplied to electricity consumers through transformers. The power supply system 10 can be implemented as an off-grid system that is not connected to the power grid 16.

[0034] The power supply system 10 may also include at least one energy storage system 17. Depending on the needs, the power supply system 10 may also include multiple energy storage systems 17. The energy storage system 17 can receive and store electricity generated by the photovoltaic module 11 and / or electricity transmitted from the power grid 16. The energy storage system 17 can efficiently supply electricity by storing electricity and supplying it to the load 14 when needed.

[0035] The energy storage system 17 may include a battery for storing electricity and a power conversion module. The battery may be equipped with a battery management system (BMS) that monitors the battery's state of charge (SOC), state of health (SOH), voltage and / or current, diagnoses the battery, and performs safety functions such as current blocking.

[0036] The power conversion module can correspond to a PCS used to perform the conversion between the power of the battery and the power of the opposite portion of the battery. For example, the PCS can perform the conversion between the DC of the battery and the AC of the opposite portion. For example, the PCS may include a bidirectional DC / DC converter connected to the battery and converting the voltage, and a bidirectional inverter connecting the DC / DC converter to the outside of the energy storage system 17.

[0037] The energy storage system 17 may also include an EMS for controlling the operation of the energy storage system 17. The EMS can control the voltage, current and / or power supplied to or output from the energy storage system 17 according to the power supply status of the battery and / or the power grid 16, and can set the operating mode of the energy storage system 17 to diagnostic mode, operating mode, etc.

[0038] If needed, an EMS coupled to a component of the power supply system 10 can control not only the operation of that component, but also the operation of another component of the power supply system 10. For example, an EMS coupled to combiner 13 or an EMS coupled to energy storage system 17 can control the operation of both combiner 13 and energy storage system 17.

[0039] The power distribution equipment 15 can provide electrical connections between the components of the power supply system 10 and can control the power flow of the power supply system 10. For example, the power distribution equipment 15 can electrically connect the photovoltaic module 11 to the load 14. For example, the power distribution equipment 15 can be connected to the device 12 connected to the photovoltaic module 11, and thus can electrically connect the photovoltaic module 11 to the load 14. If necessary, the power distribution equipment 15 can be further connected to at least one of the energy storage system 17 and the power grid 16.

[0040] For example, the power distribution equipment 15 may correspond to a switchboard that distributes power in the power supply system 10. For example, the power distribution equipment 15 may correspond to a master service panel (MSP) that distributes power generated from the photovoltaic module 11 to loads such as 14.

[0041] For example, the power distribution equipment 15 may correspond to a main controller that performs power distribution and controls each device 12 in the power supply system 10. For example, the main controller may include switches, circuit breakers, and control units. The switches, circuit breakers, and control units may each be implemented as independent devices, or at least some of the switches, circuit breakers, and control units may be included in a single device.

[0042] The main controller may include a switch that controls the electrical connections between components connected to the main controller, such as device 12 and load 14. For example, the main controller may include a relay or power semiconductor that provides or blocks electrical connections to device 12 and / or energy storage system 17 based on the drive state of each component of the power supply system 10.

[0043] The main controller can perform a rapid shutdown to stop the photovoltaic module 11 from generating electricity in an emergency (e.g., in the event of an overcurrent in the power supply system 10). For this operation, the main controller may include a circuit breaker that interrupts the connection between the device 12 and the load 14.

[0044] The main controller may include a control unit that typically controls the operation of the main controller. The control unit may also control the operation of other components of the power supply system 10 (e.g., device 12 or energy storage system 17) besides the main controller.

[0045] The control unit can control the voltage, current, and / or power output from or supplied to each component based on the power supply status of the photovoltaic module 11, device 12, combiner 13, load 14, grid 16, and / or energy storage system 17. The control unit can also set the operating mode of the main controller, device 12, and / or energy storage system 17 to diagnostic mode, operating mode, etc.

[0046] For example, the control unit can control the photovoltaic module 11, device 12, combiner 13, and / or energy storage system 17 based on the state of the power supply system 10. For example, the control unit can enable the main controller to communicate with another component of the power supply system 10 (e.g., device 12) to control that other component. Communication between the main controller and another component of the power supply system 10 can be performed using power line communication (PLC), but is not limited to this.

[0047] For example, the control unit can also control the device 12 based on the power generation status of the photovoltaic module 11. For example, the main controller can receive control commands from a server that monitors the power generation status of the photovoltaic module 11, and the control unit can control the device 12 according to the control commands.

[0048] When the power supply from the grid 16 is unstable (e.g., in an off-grid situation), the main controller can supply power to at least some of the loads 14. For example, when the power supply from the grid 16 is unstable, the main controller can preferably supply power generated from the photovoltaic module 11 and / or stored in the energy storage system 17 to standby loads that have a relatively high demand for a stable power supply.

[0049] The power supply system 10 may also include auxiliary power generation devices (e.g., diesel generators) that generate electricity in a manner distinct from separate solar power generation. For example, the auxiliary power generation devices may also be connected to the power distribution equipment 15. When the standby load cannot be handled solely by the photovoltaic modules 11 and energy storage system 17 due to environmental factors such as time zones or weather, the main controller can supply power generated by the auxiliary power generation devices to the standby load.

[0050] The control unit can be implemented by at least one processor. The processor processes commands from a computer program by performing basic arithmetic, logic, and input / output operations. These commands can be provided from the main controller's internal memory or from external devices. The processor can also typically control the operation of other components included in the main controller.

[0051] The processor can perform at least some of the data analysis, processing, and result information generation for performing the operations described above by using at least one of machine learning, neural network, or deep learning algorithms as a rule-based algorithm or artificial intelligence algorithm. Examples of neural networks can include architecture-based models such as convolutional neural networks (CNNs), deep neural networks (DNNs), and recurrent neural networks (RNNs).

[0052] For example, a processor can be implemented as an array of logic gates, or it can be implemented as a combination of a general-purpose microprocessor and a memory that stores programs that can be executed on the microprocessor. For example, a processor can include a general-purpose processor, a central processing unit (CPU), a microprocessor, a digital signal processor (DSP), a controller, a microcontroller, a state machine, etc.

[0053] In some environments, a processor can include an application-specific integrated circuit (ASIC), a programmable logic device (PLD), a field-programmable gate array (FPGA), and so on. For example, a processor can refer to a combination of processing devices, such as a combination of a DSP and a microprocessor, a combination of multiple microprocessors, a combination of one or more microprocessors and a DSP core, or a combination of any other such components.

[0054] The power supply system 10 can be implemented in various forms by combining at least some of the above components.

[0055] Figure 2 This is a diagram illustrating a voltage balancer and an off-grid system according to an embodiment.

[0056] refer to Figure 2 This illustrates an off-grid system 200 comprising an inverter 210, a voltage balancer 220, and a load. The off-grid system 200 may refer to a power supply system 10 that is not connected to the power grid 16, as referenced above. Figure 1 As stated above.

[0057] According to this disclosure, the voltage balancer 220 can be used in a photovoltaic system. In this case, the photovoltaic system can be connected to a reference system. Figure 1 The power supply system 10 described corresponds to, but is not necessarily limited to, this.

[0058] For example, voltage balancer 220 can be included with Figure 1 The inverters in the energy storage system 17 are used in combination. In another example, the voltage balancer 220 according to the embodiment can be located outside the various devices included in the power supply system 10. However, the use of the voltage balancer 220 according to the invention is not limited to the above.

[0059] In the off-grid system 200, the inverter 210 can perform off-grid functions. In this case, the off-grid function can refer to the function of the inverter 210 generating a voltage that is the same as the grid voltage in response to the continuous loads in the off-grid system 200.

[0060] At this point, inverter 210 may include a grid-connected inverter. A grid-connected inverter may refer to inverter 210 used to connect the electricity generated from the photovoltaic system to the power grid 16.

[0061] In the off-grid system 200, the inverter 210 can respond to both 240V and 120V grid voltages. For example, the inverter 210 can respond to both types of grid voltages by using an autotransformer. For instance, an autotransformer can step down the 240V output voltage generated by the inverter to 120V. However, autotransformers have the disadvantages of being large and expensive.

[0062] As another example, inverter 210 can split a 240V output voltage into two 120V output voltages to respond to both a 240V grid voltage and a 120V grid voltage. For instance, a type of split-phase inverter, such as inverter 210, can split a 240V output voltage into two 120V output voltages to respond to different types of grid voltages. See below for reference. Figures 3 to 7B The inverter 210 described in relation to the voltage balancer according to this disclosure may correspond to a split-phase inverter.

[0063] like Figure 2 As shown, the inverter 210 in off-grid mode can be used with the voltage balancer 220.

[0064] Voltage balancer 220 can refer to a device that performs voltage balancing even through the use of internal circuitry to ensure that power is supplied from each terminal of inverter 210. In this case, voltage balancer 220 can be used in conjunction with inverter 210 to perform voltage balancing. Figure 2 The voltage balancer 220 in the reference can be used with the following: Figures 3 to 8B The voltage balancer described corresponds to this.

[0065] In detail, voltage balancer 220 can be used to resolve load imbalance. Load imbalance can refer to a state where the power supplied from each terminal of inverter 210 is unbalanced due to differences in the power consumed by the loads connected to each terminal of inverter 210. In this case, voltage balancer 220 can achieve voltage balance by using internal circuitry to move the unbalanced power. Voltage balance can refer to a state where the difference in power supplied from each terminal of inverter 210 is minimized.

[0066] The internal circuitry of voltage balancer 220 may include elements such as inductors or capacitors. When voltage balancer 220 performs voltage balancing to resolve load imbalances, current may flow through the inductor included in voltage balancer 220. At this time, the current flowing in the inductor may cause inductor losses.

[0067] According to this disclosure, voltage balancer 220 may include multiple inductors to distribute the current flowing through each inductor and reduce inductor losses caused by current. Reference is made below. Figure 5 The internal circuitry of the voltage balancer 220 according to the embodiment is described in detail.

[0068] According to an embodiment, voltage balancer 220 may include a processor.

[0069] The processor can control at least a portion of the operation of the voltage balancer 220.

[0070] For example, the processor can sense a first voltage between two terminals of the inverter 210, a second voltage between one of the two terminals of the inverter 210 and the neutral point located between the two terminals of the inverter 210, and a third voltage between the other terminal of the inverter 210 and the neutral point based on the off-grid status of the power supply system 10. It can turn on at least one switch pair of the plurality of switches included in the voltage balancer 220 based on the first voltage, control the duty cycle of each drive switch among the drive switches that are not turned on based on the comparison result of the second voltage and the third voltage, and drive each drive switch based on the controlled duty cycle.

[0071] In another example, the processor can turn on the first switch pair based on the first voltage being positive.

[0072] In another example, the processor can control the duty cycle of the second switch to be equal to the duty cycle of the third switch based on the fact that the absolute value of the second voltage is equal to the absolute value of the third voltage.

[0073] In another example, the processor can control the duty cycle of the second switch to be greater than the duty cycle of the third switch based on the fact that the absolute value of the second voltage is greater than the absolute value of the third voltage, and can also control the duty cycle of the second switch to be less than the duty cycle of the third switch based on the fact that the absolute value of the second voltage is less than the absolute value of the third voltage.

[0074] In another example, the processor can turn on the second switch pair based on the first voltage being negative.

[0075] In another example, the processor can control the duty cycle of the first switch to be equal to the duty cycle of the fourth switch based on the fact that the absolute value of the second voltage is equal to the absolute value of the third voltage.

[0076] In another example, the processor can control the duty cycle of the first switch to be greater than the duty cycle of the fourth switch based on the fact that the absolute value of the second voltage is greater than the absolute value of the third voltage, and can control the duty cycle of the first switch to be less than the duty cycle of the fourth switch based on the fact that the absolute value of the second voltage is less than the absolute value of the third voltage.

[0077] In another example, the processor may perform operations to update the first voltage, the second voltage, and the third voltage based on the driving of each drive switch, and to turn on the switch pair based on the updated first voltage, the updated second voltage, and the updated third voltage, and the processor may perform operations to control the duty cycle.

[0078] A processor can be implemented using at least one of the following: application-specific integrated circuit (ASIC), digital signal processor (DSP), digital signal processing device (DSPD), programmable logic device (PLD), field-programmable gate array (FPGA), controller, microcontroller, microprocessor, and other electrical units for performing functions.

[0079] In some embodiments, the voltage balancer 220 may be driven by a device that drives the voltage balancer 220. In this case, the device that drives the voltage balancer 220 may include a processor.

[0080] The following text is for reference only. Figures 3 to 7B The various operations of the voltage balancer 220, which can be executed by the processor, are described in detail, as well as terms such as first voltage, second voltage, and third voltage.

[0081] Figure 3 This is a flowchart of a method for driving a voltage balancer according to an embodiment.

[0082] In one embodiment, the voltage balancer 220 may include multiple inductors. In this case, the voltage balancer 220 may be related to the above-mentioned reference. Figure 2The voltage balancer 220 described corresponds to this. According to this disclosure, the voltage balancer 220 may include multiple inductors, thereby reducing the magnitude of the current that can flow through each inductor during the voltage balancing process. Therefore, losses that may occur in the inductors can be reduced.

[0083] As referenced above Figure 2 As described, voltage balancing can mean that voltage balancer 220 even generates power for each terminal of inverter 210 by using internal circuitry.

[0084] According to an embodiment, voltage balancer 220 can be used in conjunction with inverter 210 to perform voltage balancing. In this case, inverter 210 can correspond to a split-phase inverter. A split-phase inverter can refer to inverter 210 that splits a 240V output voltage into two 120V output voltages.

[0085] In one embodiment, the voltage balancer 220 may include multiple switches (e.g., S1, S2, S3, and S4). Alternatively, the switches (S1, S2, S3, and S4) may be divided into switch pairs.

[0086] In an embodiment, the switch pair may include a first switch pair and a second switch pair. The first switch pair includes a first switch S1 and a fourth switch S4 from a plurality of switches, and the second switch pair includes a second switch S2 and a third switch S3 from a plurality of switches. In an embodiment, the first switch S1, the second switch S2, the third switch S3, and the fourth switch S4 may be connected in parallel with each other.

[0087] According to the embodiments, refer to Figure 5 The specific connection relationships of the components included in the internal circuit of the voltage balancer 220 will become clear.

[0088] In summary, according to the present invention, the voltage balancer 220 may include a plurality of inductors and a plurality of switches. Reference is made below. Figure 5 The internal circuitry included in the voltage balancer 220 according to the embodiment is described in detail.

[0089] In operation 310, when the power supply system 10 is in an off-grid state, the processor can sense a first voltage between the two terminals of the inverter 210, a second voltage between one of the two terminals of the inverter 210 and the neutral point located between the two terminals of the inverter 210, and a third voltage between the other of the two terminals of the inverter 210 and the neutral point.

[0090] The fact that the power supply system 10 is in an off-grid state can mean that the power supply system 10 is an off-grid system 200 that is not connected to the power grid 16.

[0091] According to an embodiment, the first voltage may correspond to the voltage between the two terminals of the inverter 210. For example, the first voltage may correspond to a value obtained by subtracting the voltage of one terminal from the voltage of the other terminal of the inverter 210. (See reference...) Figure 2 The voltages at the terminals of inverter 210 are shown as V. live1 and V live2 At this point, the first voltage can be connected to the voltage from V. live1 Subtract V live2 The obtained value corresponds to this.

[0092] According to an embodiment, the second voltage may correspond to the voltage between one of the two terminals of the inverter 210 and the neutral point 510 between the two terminals of the inverter 210. In this case, the neutral point 510 may refer to a reference point symmetrical about the voltages of the two terminals of the inverter 210. (See reference...) Figure 5 The second voltage is shown as V. L1N .

[0093] According to an embodiment, the third voltage may correspond to the voltage between the other terminal of the inverter 210 and the neutral point 510 between the two terminals of the inverter 210. (See reference...) Figure 5 The third voltage is shown as V. L2N .

[0094] The following is for reference. Figure 4 Provide a detailed description of the first to third voltages.

[0095] In operation 320, the processor can turn on at least one pair of switches (S1, S2, S3 and S4) of the voltage balancer 220 based on the first voltage.

[0096] In one embodiment, the processor can turn on the first switch pair when the first voltage is positive. This may be to enable the processor to perform voltage balancing when the first voltage is positive. (See below for reference.) Figure 6 and Figure 7A as well as Figure 7B A method for voltage balancing performed by a processor when the first voltage is positive, according to an embodiment, is described in detail.

[0097] In one embodiment, the processor can turn on the second switch pair when the first voltage is negative. This can be used by the processor according to the embodiment to perform voltage balancing when the first voltage is negative. Reference is made below. Figure 6 and Figure 8A as well as Figure 8B A method for voltage balancing performed by a processor when the first voltage is negative, according to an embodiment, is described in detail.

[0098] In operation 330, the processor can control the duty cycle of each drive switch that is not yet turned on among a plurality of switches based on the result of comparing the second voltage with the third voltage.

[0099] Duty cycle can refer to the percentage of time a switch is on in a single switching cycle. A switching cycle can refer to the time it takes for a switching element to turn on and off once during this period. A drive switch can refer to a switch that is not turned on during operation 320. According to an embodiment, the processor can perform voltage balancing by controlling the duty cycle of each drive switch based on a second voltage and a third voltage.

[0100] In an embodiment, the processor can control the duty cycles of the second switch S2 and the third switch S3 to be the same when the absolute values ​​of the second voltage and the third voltage are the same.

[0101] In this embodiment, the processor can control the duty cycle of the second switch S2 to be greater than the duty cycle of the third switch S3 when the absolute value of the second voltage is greater than the absolute value of the third voltage, and can control the duty cycle of the second switch S2 to be less than the duty cycle of the third switch S3 when the absolute value of the second voltage is less than the absolute value of the third voltage.

[0102] In an embodiment, the processor can control the duty cycles of the first switch S1 and the fourth switch S4 to be the same when the absolute value of the second voltage is the same as the absolute value of the third voltage.

[0103] In this embodiment, the processor can control the duty cycle of the first switch S1 to be greater than the duty cycle of the fourth switch S4 when the absolute value of the second voltage is greater than the absolute value of the third voltage, and can control the duty cycle of the first switch S1 to be less than the duty cycle of the fourth switch S4 when the absolute value of the second voltage is less than the absolute value of the third voltage.

[0104] The following is for reference. Figures 6 to 8B The present invention describes a method, according to an embodiment, for a processor to control the duty cycle of each drive switch based on the result of comparing the absolute value of a second voltage with the absolute value of a third voltage.

[0105] In operation 340, the processor can drive each drive switch based on a controlled duty cycle. According to an embodiment, the processor can achieve voltage balancing through operation 340. Here, voltage balancing can refer to a state that minimizes the difference in power supplied from each terminal of the inverter 210.

[0106] According to this disclosure, since the voltage balancer 220 includes multiple inductors in its internal circuitry, inductor losses that may occur during the voltage balancing process performed by the processor can be reduced.

[0107] For example, during voltage balancing performed by the processor, inductor losses can be reduced by distributing the current that might flow in the inductors to multiple inductors included in the voltage balancer 220. (Reference) Figure 7A , Figure 7B , Figure 8A and Figure 8B The diagram illustrates the current (e.g., 710a, 720a, 710b, 720b, 810a, 820a, 810b and 820b) that may flow in the inductor during the voltage balancing process performed by the processor, according to an embodiment.

[0108] The following is for reference. Figure 5 The internal circuitry of the voltage balancer 220, which includes multiple inductors, is described in detail.

[0109] In this embodiment, the processor can perform operations such as updating a first voltage, a second voltage, and a third voltage based on driving each drive switch, turning on switch pairs based on the updated first voltage, the updated second voltage, and the updated third voltage, and controlling the duty cycle (not shown). In this way, according to this embodiment, the processor can continuously perform voltage balancing.

[0110] The following is for reference. Figures 6 to 8B A method for voltage balancing performed by a processor according to an embodiment is described in detail.

[0111] Figure 4 This is a diagram illustrating a first voltage, a second voltage, and a third voltage that can be sensed by a voltage balancer according to an embodiment.

[0112] Figure 4 The variations of the first voltage 430, the second voltage 440, and the third voltage 450 over time are shown.

[0113] As referenced above Figure 3 As described in operation 310, when the power supply system 10 is in an off-grid state, the processor can sense a first voltage 430 between the two terminals of the inverter 210, a second voltage 440 between one of the two terminals of the inverter 210 and the neutral point 510 between the two terminals of the inverter 210, and a third voltage 450 between the other of the two terminals of the inverter 210 and the neutral point 510.

[0114] At this point, inverter 210 can be referenced above. Figure 2 The inverter 210 described corresponds to this.

[0115] The first voltage 430 can correspond to the voltage between the two terminals of the inverter 210. For example, the first voltage 430 can correspond to a value obtained by subtracting the voltage of one terminal from the voltage of the other terminal of the inverter 210. This can correspond to V. live1 and V live2 The voltages between them are respectively Figure 2 The voltage at the two terminals of the inverter 210 in the circuit. For example, the first voltage can be connected to the voltage from V... live1 Subtract V live2 The obtained value corresponds to this.

[0116] The voltages at the terminals of inverter 210 can have a phase difference from each other. For example, the voltage at one terminal of inverter 210 and the voltage at the other terminal can have a 180-degree phase difference. Therefore, as... Figure 4 As shown, at a specific time, the second voltage 440 and the third voltage 450 can be positive and negative or negative and positive, respectively.

[0117] As referenced above Figure 3 The second voltage 440 can correspond to the voltage between one of the two terminals of the inverter 210 and the neutral point 510 between the two terminals of the inverter 210. Similarly, as referenced above... Figure 3 The third voltage 450 can correspond to the voltage between the other terminal of the inverter 210 and the neutral point 510 between the two terminals of the inverter 210. The neutral point 510 can be a reference point where the voltages of the two terminals of the inverter 210 are symmetrical about each other.

[0118] According to an embodiment, the processor can use a second voltage 440 and a third voltage 450 to control the duty cycle of the drive switch. In this embodiment, the processor can control the duty cycle of the drive switch based on the result of comparing the absolute value of the second voltage 440 with the absolute value of the third voltage 450. In this case, the processor can resolve the voltage imbalance at each terminal of the inverter 210 by performing voltage balancing based on the controlled duty cycle and the moving power.

[0119] Figure 4 The regions 410 and 420 where the first voltage 430 is positive and negative, respectively, are shown.

[0120] When the first voltage 430 is positive, this can mean that the second voltage 440 is positive and the third voltage 450 is negative. In this case, the value obtained by subtracting the negative third voltage 450 from the positive second voltage 440 can be positive, making the first voltage 430 positive.

[0121] In some embodiments, when the first voltage 430 is negative, this can mean that the second voltage 440 is negative and the third voltage 450 is positive. In this case, the value obtained by subtracting the positive third voltage 450 from the negative second voltage 440 can be positive, making the first voltage 430 negative.

[0122] Figure 5 This is a diagram showing the internal circuitry of a voltage balancer according to an embodiment.

[0123] refer to Figure 5 The diagram shows the internal circuitry of the voltage balancer 220, which includes multiple capacitors, multiple switches, and multiple inductors.

[0124] In one embodiment, the voltage balancer 220 may include multiple switches (e.g., S1, S2, S3, and S4). Alternatively, the switches (S1, S2, S3, and S4) may be grouped into multiple switch pairs.

[0125] In an embodiment, the switch pair may include a first switch pair and a second switch pair. The first switch pair includes a first switch S1 and a fourth switch S4 among a plurality of switches, and the second switch pair includes a second switch S2 and a third switch S3 among a plurality of switches. The first switch S1 and the second switch S2 may be connected in parallel with the third switch S3 and the fourth switch S4, respectively.

[0126] refer to Figure 5 According to an embodiment, a plurality of switches (S1, S2, S3, and S4) are shown included in the internal circuitry of the voltage balancer 220. In this case, the first switch S1 and the second switch S2 can be connected in series with each other.

[0127] The third switch S3 and the fourth switch S4 can be connected in series. As mentioned above, the first switch S1 and the second switch S2 can be connected in parallel with the third switch S3 and the fourth switch S4, respectively.

[0128] According to an embodiment, the processor can perform voltage balancing by turning on a switch based on a first voltage to a third voltage.

[0129] In this embodiment, each of the switches (S1, S2, S3, and S4) may correspond to a power semiconductor switch. The power semiconductor switch may be a switchable semiconductor device that can be used to control power flow.

[0130] In an embodiment, the internal circuitry of the voltage balancer 220 may include multiple inductors (e.g., L1 and L2). Thus, when the processor performs voltage balancing, the current flowing through each of the inductors (L1 or L2) can be distributed among the inductors (L1 and L2), thereby reducing losses occurring in the inductors (L1 or L2).

[0131] For example, the internal circuitry of voltage balancer 220 may include a first inductor L1 and a second inductor L2. Therefore, when the processor performs voltage balancing, the current flowing through each of the inductors (L1 and L2) can be shunted, such that half of the total current can flow to either the first inductor L1 or the second inductor L2.

[0132] The power loss that may occur in a particular component can be correlated with the product of the resistance and the square of the current. Therefore, when the voltage balancer 220 according to the embodiment is used, a current corresponding to half of the total current can be applied to each of the first inductor L1 and the second inductor L2, such that the loss occurring in each of the inductors (L1 and L2) can be reduced to one-quarter.

[0133] According to this disclosure, the processor can perform voltage balancing via the internal circuitry of the voltage balancer 220, including inductors (L1 and L2), such as Figure 5 As shown, this enables parallel operation of the inductors (L1 and L2) and reduces losses in the inductors (L1 and L2). In one embodiment, a capacitor (C1) may be connected between the inductors (L1 and L2).

[0134] Figure 6 This is a diagram illustrating a method for performing voltage balancing by a voltage balancer according to an embodiment.

[0135] In operation 610, the processor can sense a first voltage, a second voltage, and a third voltage. (See above for reference.) Figure 3 and Figure 4 The first to third voltages have been described, therefore the description of the first to third voltages is omitted.

[0136] In one embodiment, the processor may turn on at least one switch pair of a plurality of switches included in the voltage balancer 220 based on a first voltage.

[0137] In operation 620, the processor can determine whether the first voltage is positive. When the first voltage is positive, this can mean that the second voltage is positive and the third voltage is negative, as referenced above. Figure 4 As mentioned above. Similarly, when the first voltage is negative, this could mean that the second voltage is negative and the third voltage is positive, as referenced above. Figure 4 As stated above.

[0138] At this time, the processor can execute operation 630 when the first voltage is positive, and can execute operation 640 when the first voltage is not positive. Therefore, different switch pairs can be turned on depending on whether the first voltage is positive or not. Therefore, the operation of the voltage balancer 220 when the first voltage is positive can be different from the operation of the voltage balancer 220 when the first voltage is negative.

[0139] Figure 7A and Figure 7B The processor according to an embodiment is shown performing voltage balancing when the first voltage is positive. Figure 8A and Figure 8B The processor according to an embodiment is shown performing voltage balancing when the first voltage is negative.

[0140] The following describes the operation of the processor when the first voltage sensed by the processor is positive.

[0141] In operation 630, the processor can turn on the first switch pair. In an embodiment, when the first voltage is positive, the processor can turn on the first switch pair. At this time, the first switch pair may include a first switch S1 and a fourth switch S4.

[0142] In an embodiment, the processor may control the duty cycle of each of the non-activated drive switches among a plurality of switches based on the result of comparing a second voltage with a third voltage. The method of controlling the duty cycle of each drive switch by the processor is described in detail below with reference to operations 631 to 635.

[0143] In operation 631, the processor can determine whether the absolute values ​​of the second voltage and the third voltage are equal. If the absolute values ​​of the second voltage and the third voltage are equal, the processor can execute operation 635.

[0144] In operation 635, when the absolute value of the second voltage is equal to the absolute value of the third voltage, the processor can control the duty cycle of the second switch S2 to be equal to the duty cycle of the third switch S3. For example, when the absolute value of the second voltage is equal to the absolute value of the third voltage, the processor can control the duty cycle of the second switch S2 and the third switch S3 to 0.5.

[0145] At this point, the duty cycle of each drive switch can be controlled based on power loss. For example, the duty cycles of the drive switches can be controlled to 0.495 and 0.505 respectively to compensate for power loss. Alternatively, the duty cycle of each drive switch can be continuously controlled based on power loss. Similarly, in subsequent operations, the duty cycle of each drive switch can be controlled based on power loss.

[0146] This could mean that within one switching cycle, the time when the first switch S1, the fourth switch S4, and the second switch S2 are turned on is equal to the time when the first switch S1, the fourth switch S4, and the third switch S3 are turned on.

[0147] Figure 7A and Figure 7B This is a diagram illustrating a method for voltage balancing performed by a voltage balancer according to an embodiment when the first voltage is positive. In detail, Figure 7AThis shows that when the first voltage is positive, the first switch S1, the fourth switch S4, and the second switch S2 are connected. Figure 7B This shows that when the first voltage is positive, the first switch S1, the fourth switch S4, and the third switch S3 are turned on.

[0148] In one embodiment, when the processor performs operation 635 to control the duty cycles of the second switch S2 and the third switch S3 to be equal, the processor... Figure 7A The time and processor during the operation are shown as follows Figure 7B The time during the operation shown can be equal within one cycle. This allows voltage balance to be maintained.

[0149] Otherwise, when the absolute value of the second voltage is not equal to the absolute value of the third voltage, the processor can execute operation 632.

[0150] In operation 632, the processor can determine whether the absolute value of the second voltage is greater than the absolute value of the third voltage.

[0151] In this embodiment, when the absolute value of the second voltage is greater than the absolute value of the third voltage, the processor can control the duty cycle of the second switch S2 to be greater than the duty cycle of the third switch S3, and when the absolute value of the second voltage is less than the absolute value of the third voltage, the processor can control the duty cycle of the second switch S2 to be less than the duty cycle of the third switch S3.

[0152] For example, when the absolute value of the second voltage is greater than the absolute value of the third voltage, the processor can execute operation 633. In another example, when the absolute value of the second voltage is less than the absolute value of the third voltage, the processor can execute operation 634.

[0153] In operation 633, the processor can control the duty cycle of the second switch S2 to be greater than the duty cycle of the third switch S3.

[0154] This could mean that within a switching cycle, the time that the first switch S1, the fourth switch S4, and the second switch S2 are on is longer than the time that the first switch S1, the fourth switch S4, and the third switch S3 are on. In this case, within a cycle, the processor... Figure 7A The operation shown can take longer than the processor, such as Figure 7B The operation time is shown. This allows for voltage balance to be achieved.

[0155] In operation 634, the processor can control the duty cycle of the second switch S2 to be less than the duty cycle of the third switch S3.

[0156] This could mean that within a switching cycle, the on-time of the first switch S1, the fourth switch S4, and the second switch S2 is shorter than the on-time of the first switch S1, the fourth switch S4, and the third switch S3. At this time, within a cycle, the processor... Figure 7A The operation time shown can be shorter than that of a processor, such as... Figure 7B The operation time is shown. This allows for voltage balance to be achieved.

[0157] In this embodiment, the processor may drive each drive switch based on a duty cycle. The method of driving each drive switch by a processor based on a controlled duty cycle has been described above with reference to operations 631 to 635, and therefore its detailed description is omitted.

[0158] The following describes how the processor operates when the first voltage sensed by the processor is negative.

[0159] In operation 640, the processor can turn on the second switch pair. In an embodiment, when the first voltage is negative, the processor can turn on the second switch pair. At this time, the second switch pair may include a second switch S2 and a third switch S3.

[0160] As described above with reference to operation 630, according to an embodiment, the processor can control the duty cycle of each drive switch that is not turned on among a plurality of switches based on the result of comparing the second voltage with the third voltage. The method by which the processor controls the duty cycle of each drive switch based on the result of comparing the second voltage with the third voltage is described below with reference to operations 635 and 641 to 644.

[0161] In operation 641, the processor can determine whether the absolute values ​​of the second voltage and the third voltage are equal. In an embodiment, when the absolute value of the second voltage equals the absolute value of the third voltage, the processor can control the duty cycle of the first switch S1 to be equal to the duty cycle of the fourth switch S4. For example, when the absolute value of the second voltage equals the absolute value of the third voltage, the processor can execute operation 635.

[0162] In operation 635, when the absolute value of the second voltage is equal to the absolute value of the third voltage, the processor can control the duty cycle of the first switch S1 to be equal to the duty cycle of the fourth switch S4. For example, when the absolute value of the second voltage is equal to the absolute value of the third voltage, the processor can control the duty cycle of the first switch S1 and the fourth switch S4 to 0.5.

[0163] This means that within one switching cycle, the time that the second switch S2, the third switch S3, and the first switch S1 are on is equal to the time that the second switch S2, the third switch S3, and the fourth switch S4 are on. Therefore, voltage balance can be maintained.

[0164] Figure 8A and Figure 8B This shows that the processor performs voltage balancing when the first voltage is negative.

[0165] In detail, Figure 8A This shows that when the first voltage is negative, the second switch S2, the third switch S3, and the fourth switch S4 are turned on. Figure 8B It shows that when the first voltage is negative, the second switch S2, the third switch S3 and the first switch S1 are turned on.

[0166] In this embodiment, when the processor performs operation 635 to control the duty cycles of the second switch S2 and the third switch S3 to be equal, the processor... Figure 8A The time and processor during the operation are shown as follows Figure 8B The time during the operation shown can be equal within one cycle. Therefore, the voltage at each terminal of the inverter 210 can be kept uniform.

[0167] Otherwise, when the absolute value of the second voltage is not equal to the absolute value of the third voltage, the processor can execute operation 642.

[0168] In operation 642, the processor can determine whether the absolute value of the second voltage is greater than the absolute value of the third voltage.

[0169] In this embodiment, when the absolute value of the second voltage is greater than the absolute value of the third voltage, the processor can control the duty cycle of the first switch S1 to be greater than the duty cycle of the fourth switch S4, and when the absolute value of the second voltage is less than the absolute value of the third voltage, the processor can control the duty cycle of the first switch S1 to be less than the duty cycle of the fourth switch S4.

[0170] For example, when the absolute value of the second voltage is greater than the absolute value of the third voltage, the processor can execute operation 643. In another example, when the absolute value of the second voltage is less than the absolute value of the third voltage, the processor can execute operation 644.

[0171] In operation 643, the processor can control the duty cycle of the first switch S1 to be greater than the duty cycle of the fourth switch S4.

[0172] This could mean that within one switching cycle, the time that the second switch S2, the third switch S3, and the first switch S1 are on is longer than the time that the second switch S2, the third switch S3, and the fourth switch S4 are on. In this case, within one cycle, the processor... Figure 8B The operation shown can take longer than the processor, such as Figure 8A The operation time is shown. This allows for voltage balance to be achieved.

[0173] In operation 644, the processor can control the duty cycle of the first switch S1 to be less than the duty cycle of the fourth switch S4.

[0174] This could mean that within a switching cycle, the on-time of the second switch S2, the third switch S3, and the first switch S1 is shorter than the on-time of the second switch S2, the third switch S3, and the fourth switch S4. At this time, within a cycle, the processor... Figure 8B The operation time shown can be shorter than that of a processor, such as... Figure 8A The operation time is shown. This allows for voltage balance to be achieved.

[0175] In an embodiment, the processor may perform operations (not shown) to update the first voltage, the second voltage, and the third voltage based on driving and turning on each drive switch pair, and operations (not shown) to control the duty cycle based on the updated first voltage, the updated second voltage, and the updated third voltage.

[0176] For example, the processor can repeatedly execute based on the updated first voltage to the updated third voltage. Figure 6 The operation shown is to continuously achieve voltage balance.

[0177] Figure 7A and Figure 7B This is a diagram illustrating a method by which a voltage balancer performs voltage balancing when the first voltage is positive, according to an embodiment.

[0178] refer to Figure 7A This illustrates that when the first voltage is positive, the first switch S1, the fourth switch S4, and the second switch S2 are connected. Figure 7B The diagram shows that when the first voltage is positive, the first switch S1, the fourth switch S4, and the third switch S3 are turned on. According to an embodiment, when the first voltage is positive, the processor can, based on a controlled duty cycle, [control the following actions]: Figure 7A or Figure 7B The operation shown is used to perform voltage balancing.

[0179] As referenced above Figure 6 As stated, when the first voltage is positive and the absolute value of the second voltage is greater than the absolute value of the third voltage, within one cycle, the processor... Figure 7A The operation shown can take longer than the processor, such as Figure 7B The time of the operation shown.

[0180] Similarly, when the first voltage is positive and the absolute value of the second voltage is less than the absolute value of the third voltage, within one cycle, the processor... Figure 7A The operation time shown can be shorter than that of a processor, such as... Figure 7B The time of the operation shown.

[0181] Figure 8A and Figure 8B This is a diagram illustrating a method by which a voltage balancer performs voltage balancing when the first voltage is negative, according to an embodiment.

[0182] refer to Figure 8A This shows that when the first voltage is negative, the second switch S2, the third switch S3, and the fourth switch S4 are turned on. Figure 8B This illustrates that when the first voltage is negative, the second switch S2, the third switch S3, and the first switch S1 are connected. According to an embodiment, when the first voltage is negative, the processor can, based on a controlled duty cycle, [perform actions such as...]. Figure 8A or Figure 8B The operation shown is used to perform voltage balancing.

[0183] As referenced above Figure 6 As stated, when the first voltage is negative and the absolute value of the second voltage is greater than the absolute value of the third voltage, within one cycle, the processor... Figure 8B The operation shown can take longer than the processor, such as Figure 8A The time of the operation shown.

[0184] Similarly, when the first voltage is negative and the absolute value of the second voltage is less than the absolute value of the third voltage, within one cycle, the processor... Figure 8B The operation time shown can be shorter than that of a processor, such as... Figure 8A The time of the operation shown.

[0185] like Figure 7A and Figure 7B as well as Figure 8A and Figure 8B As shown, during the voltage balancing process performed by the processor according to the embodiment, the current flowing in the inductor can be divided into a first current 710a, 710b, 810a or 810b and a second current 720a, 720b, 820a or 820b. At this time, the first current 710a, 710b, 810a or 810b may refer to the current flowing in the first inductor L1. The second current 720a, 720b, 820a or 820b may refer to the current flowing in the second inductor L2. During the voltage balancing process performed by the processor according to the embodiment, the sum of the first current 710a, 710b, 810a or 810b and the second current 720a, 720b, 820a or 820b may be equal to the current that can flow in the inductor.

[0186] refer to Figure 7A and Figure 7B This illustrates that a first current 710a or 710b flows in the first inductor L1, and a second current 720a or 720b flows in the second inductor L2. (Reference) Figure 8A and Figure 8B The diagram shows a first current 810a or 810b flowing in a first inductor L1, and a second current 820a or 820b flowing in a second inductor L2.

[0187] As described above, according to this disclosure, the processor can perform voltage balancing through the internal circuitry of the voltage balancer 220, which includes multiple inductors (L1 and L2), thereby enabling parallel operation of the inductors (L1 and L2) and reducing potential losses in each of the inductors (L1 and L2).

[0188] According to the problem-solving unit of the present disclosure described above, a voltage balancer including multiple inductors and a method for driving the voltage balancer can be provided, thereby reducing losses in the inductors included in the voltage balancer and in the method for driving the voltage balancer.

[0189] The embodiments described above can be implemented as computer programs that can be executed on a computer using various components. The computer programs can be stored on a computer-readable medium.

[0190] At this time, computer-readable media may include magnetic media such as hard disks, floppy disks, or magnetic tapes; optical recording media such as compact disc read-only memory (CD-ROM) or digital versatile disk (DVD); magneto-optical media such as floppy disks; or hardware devices such as ROM, random access memory (RAM), or flash memory, specifically configured to store and execute program instructions.

[0191] Computer programs may be specifically designed and configured for this disclosure, or may be known and available to those skilled in the art of computer software. Examples of computer programs may include machine code created by a compiler and high-level language code that can be executed on a computer using an interpreter.

[0192] The specific implementations described herein are illustrative examples of embodiments and are not intended to limit the scope of the embodiments in any way. For brevity, conventional electronic components, control systems, software development, and other functional aspects of the system may be described in detail. Furthermore, the connecting lines or connecting members between components shown in the accompanying drawings are merely illustrative of functional connections and / or physical or electrical connections. In actual devices, connections between components may be represented by functional connections, physical connections, or electrical connections that can be replaced or added. Moreover, no component is essential to the practice of this invention unless it is specifically described as "essential" or "critical."

[0193] In the context of describing embodiments (particularly in the context of the appended claims), the terms “a” and “an” and “the”, and similar designations, shall be interpreted to cover both the singular and the plural. Furthermore, unless otherwise stated herein, the description of value ranges herein is intended only as a way of abbreviating each individual value falling within that range, and each individual value is incorporated into the specification as if it were described separately herein.

[0194] Unless otherwise stated herein or clearly contradicted by the context, all methods described herein may be performed in any suitable order. The invention is not necessarily limited to the described order of operations. Unless otherwise required, the use of any or all examples or language (e.g., “such as”) provided herein is intended only to illustrate the invention and does not constitute a limitation on the scope of the invention. Many modifications and adaptations will be apparent to those skilled in the art without departing from the spirit and scope of the appended claims or their equivalents.

[0195] Therefore, the spirit of the present invention should not be limited to the above embodiments, and the scope of the appended claims and the scope of their equivalents or modifications are included within the spirit of the present invention.

Claims

1. A method for driving a voltage balancer, the method comprising: Based on the power supply system being in an off-grid state, a first voltage between two terminals of the inverter, a second voltage between one of the two terminals of the inverter and a neutral point located between the two terminals of the inverter, and a third voltage between the other terminal of the inverter and the neutral point; Based on the first voltage, at least one switch pair among the plurality of switches included in the voltage balancer is turned on; Based on the result of comparing the second voltage with the third voltage, the duty cycle of each drive switch that is not turned on among the plurality of switches is controlled; as well as Each drive switch is driven based on the controlled duty cycle.

2. The method according to claim 1, wherein, The voltage balancer includes multiple inductors.

3. The method according to claim 1, wherein, The at least one switch pair includes a first switch pair and a second switch pair, the first switch pair including a first switch and a fourth switch from the plurality of switches, and the second switch pair including a second switch and a third switch from the plurality of switches. The first switch and the second switch are connected in parallel with the third switch and the fourth switch, respectively.

4. The method according to claim 3, wherein, Turning on the at least one switch pair includes: turning on the first switch pair based on the first voltage being positive.

5. The method according to claim 4, wherein, Controlling the duty cycle includes: based on the fact that the absolute value of the second voltage is equal to the absolute value of the third voltage, controlling the duty cycle of the second switch to be equal to the duty cycle of the third switch.

6. The method according to claim 4, wherein, Controlling the duty cycle includes: Based on the fact that the absolute value of the second voltage is greater than the absolute value of the third voltage, the duty cycle of the second switch is controlled to be greater than the duty cycle of the third switch; and Based on the fact that the absolute value of the second voltage is less than the absolute value of the third voltage, the duty cycle of the second switch is controlled to be less than the duty cycle of the third switch.

7. The method according to claim 3, wherein, Turning on the at least one switch pair includes: The second switch pair is activated based on the first voltage being negative.

8. The method according to claim 7, wherein, Controlling the duty cycle includes: Based on the fact that the absolute value of the second voltage is equal to the absolute value of the third voltage, the duty cycle of the first switch is controlled to be equal to the duty cycle of the fourth switch.

9. The method according to claim 7, wherein, Controlling the duty cycle includes: Based on the fact that the absolute value of the second voltage is greater than the absolute value of the third voltage, the duty cycle of the first switch is controlled to be greater than the duty cycle of the fourth switch; and Based on the fact that the absolute value of the second voltage is less than the absolute value of the third voltage, the duty cycle of the first switch is controlled to be less than the duty cycle of the fourth switch.

10. The method according to claim 1, further comprising: The first voltage, the second voltage, and the third voltage are updated based on the driving of each drive switch; as well as The switching on of the at least one switch pair and the control of the duty cycle are performed based on the updated first voltage, the updated second voltage, and the updated third voltage.

11. A computer-readable recording medium having a program recorded thereon, the program being used to cause a computer to perform the method according to any one of claims 1 to 10.

12. A voltage balancer, the voltage balancer comprising a processor, the processor being configured to: Based on the power supply system being in an off-grid state, the system senses a first voltage between two terminals of the inverter, a second voltage between one of the two terminals of the inverter and a neutral point located between the two terminals of the inverter, and a third voltage between the other terminal of the inverter and the neutral point. Based on the first voltage, at least one switch pair among the plurality of switches included in the voltage balancer is turned on; Based on the result of comparing the second voltage with the third voltage, the duty cycle of each drive switch that is not turned on among the plurality of switches is controlled; as well as Each drive switch is driven based on the controlled duty cycle.

13. The voltage balancer according to claim 12, wherein, The at least one switch pair includes a first switch pair and a second switch pair, the first switch pair including a first switch and a fourth switch from the plurality of switches, and the second switch pair including a second switch and a third switch from the plurality of switches. The first switch and the second switch are connected in parallel with the third switch and the fourth switch, respectively.

14. The voltage balancer according to claim 13, wherein, The processor is also configured to turn on the first switch pair based on the first voltage being positive.

15. The voltage balancer according to claim 14, wherein, The processor is also configured to control the duty cycle of the second switch to be equal to the duty cycle of the third switch based on the absolute value of the second voltage being equal to the absolute value of the third voltage.

16. The voltage balancer according to claim 14, wherein, The processor is also configured to: Based on the fact that the absolute value of the second voltage is greater than the absolute value of the third voltage, the duty cycle of the second switch is controlled to be greater than the duty cycle of the third switch; as well as Based on the fact that the absolute value of the second voltage is less than the absolute value of the third voltage, the duty cycle of the second switch is controlled to be less than the duty cycle of the third switch.

17. The voltage balancer according to claim 13, wherein, The processor is also configured to turn on the second switch pair based on the first voltage being negative.

18. The voltage balancer according to claim 17, wherein, The processor is further configured to control the duty cycle of the first switch to be equal to the duty cycle of the fourth switch, based on the fact that the absolute value of the second voltage is equal to the absolute value of the third voltage.

19. The voltage balancer according to claim 17, wherein, The processor is also configured to: Based on the fact that the absolute value of the second voltage is greater than the absolute value of the third voltage, the duty cycle of the first switch is controlled to be greater than the duty cycle of the fourth switch; as well as Based on the fact that the absolute value of the second voltage is less than the absolute value of the third voltage, the duty cycle of the first switch is controlled to be less than the duty cycle of the fourth switch.

20. The voltage balancer according to claim 12, wherein, The processor is also configured to: The first voltage, the second voltage, and the third voltage are updated based on the driving of each drive switch; as well as The at least one switch pair is turned on and the duty cycle is controlled based on the updated first voltage, the updated second voltage, and the updated third voltage.

Images