Power Compensation Device for Improving the Output of Agricultural Solar Photovoltaic (PV) Power Generation Systems
Patent Information
- Application Number
- KR1020250026309
- Authority / Receiving Office
- KR · KR
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2025-02-28
- Publication Date
- 2026-09-04
Smart Images
Figure PAT00001_ABST
Abstract
Description
Technology Field
[0001] The present invention relates to an output compensation device for solving the problem of output degradation occurring in an agricultural photovoltaic (PV) power generation system that combines agriculture and photovoltaic power generation. More specifically, it is a technology that improves the efficiency of a photovoltaic power generation system by considering changes in sunlight intensity, partial shading, and seasonal influences in a crop cultivation environment. Background Technology
[0002] Agri-PV (Agrivoltaics) systems are designed to perform both agriculture and power generation simultaneously by installing solar panels on farmland. Unlike conventional solar power systems, agri-PV systems require adjustments to the placement, height, light transmittance, and angle of solar panels to accommodate crop cultivation, and partial shading frequently occurs depending on the season and crop growth stage. This is one of the major factors causing a decrease in the power generation efficiency of solar modules.
[0003] Conventional string-type solar power systems generate electricity by connecting multiple solar modules in series. However, if partial shading occurs on some modules, the nature of the series connection structure causes current bottlenecks, resulting in a decrease in overall output. While various output compensation technologies, such as micro-inverters and DC optimizers, have been developed to address this issue, methods optimized for agro-solar environments are currently lacking. Furthermore, existing technologies suffer from insufficient research regarding the optimization of power generation systems that consider crop growth and photosynthetic efficiency. The problem to be solved
[0004] The present invention provides an output compensation device to solve the problems of partial shading and output degradation due to crop growth in an agrophotovoltaic power generation system. Through this, the aim is to maximize solar power generation efficiency while maintaining agricultural productivity. Furthermore, by optimizing the output of solar panels by considering seasonal changes in light conditions and enhancing crop protection functions, it enables sustainable agriculture and energy production. means of solving the problem
[0005] An output compensation device for improving the output of a photovoltaic PV power generation system according to the present invention comprises: a plurality of photovoltaic modules connected in series; an inverter connected to the output terminals of the plurality of photovoltaic modules; a plurality of output compensation devices connected to each of the plurality of photovoltaic modules; and a gateway communicating with the plurality of output compensation devices. In a photovoltaic PV power generation system, the plurality of output compensation devices each comprises: a Wi-Fi mesh module configured to wirelessly communicate with the gateway or the plurality of output compensation devices via a Wi-Fi method; a sensing unit that senses the input voltage and input current of the photovoltaic module and senses its own current output voltage; a microprocessor that collects data from other output compensation devices through the Wi-Fi mesh module to calculate a reference average output current, calculates its own current output current using the input voltage, input current, and current output voltage sensed through the sensing unit, selects an operating mode by comparing the current output current and the current output voltage with a maximum allowable current, a minimum allowable voltage, and a reference average output current, and outputs a control signal according to the selected operating mode; and a PWM controller that outputs a PWM (Pulse Width Modulation) signal according to the control signal of the microprocessor. It may include a gate driver and a power control module that control their own output voltage and output current according to the PWM signal of the PWM controller.
[0006] In some examples, the microprocessor may operate in a CDOWN mode that lowers the output current and raises the output voltage when the current output current is higher than the maximum allowable current.
[0007] In some examples, the microprocessor may output a control signal to increase the duty value of the gate driver in the CDOWN mode.
[0008] In some examples, the microprocessor may operate in a bypass mode that transmits the power produced by the string without the output compensation device intervening when the current output voltage is lower than the minimum allowable voltage.
[0009] In some examples, the microprocessor may output a control signal to transmit the power produced by the solar module in the bypass mode directly to the inverter.
[0010] In some examples, the microprocessor may operate in a CUP mode that increases the output current when the current output current is lower than the reference average output current by a set percentage.
[0011] In some examples, the microprocessor may output a control signal to lower the duty value of the gate driver in the CUP mode.
[0012] In some examples, the microprocessor may operate in a CDOWN mode that lowers the output current and raises the output voltage when the current output current is set percentage higher than the reference average output current.
[0013] In some examples, the microprocessor may operate in an MPPT mode to output at maximum power while adjusting the output voltage and output current with a maximum power tracking algorithm when the current output current is within a set percentage of the reference average output current.
[0014] In some examples, the microprocessor can output a control signal to increase or decrease the duty value of the gate driver in the MPPT mode so that the output power value becomes higher than the previous output power value.
[0015] In some examples, the microprocessor may operate in RS mode to forcibly cut off power when it receives a rapid power cutoff command from the gateway through the Wi-Fi mesh module.
[0016] In some examples, the microprocessor may output a control signal to cut off power output by controlling the duty value of the gate driver in the RS mode. Effects of the invention
[0017] According to the present invention, the problem of output degradation occurring in an agricultural photovoltaic power generation system can be minimized, thereby enabling the coexistence of agriculture and photovoltaic power generation and improving profitability compared to existing photovoltaic power generation systems. In addition, the efficiency of system maintenance can be increased through a real-time data-based output correction function. Brief explanation of the drawing
[0018] FIG. 1 is a schematic diagram illustrating the configuration of a mesh-based wireless communication system among exemplary photovoltaic PV power generation systems according to the present invention. FIG. 2 is a block diagram illustrating the configuration of an output compensation device in an exemplary photovoltaic PV power generation system according to the present invention. FIG. 3 is a table summarizing the operation modes and descriptions of the output compensation device in an exemplary photovoltaic PV power generation system according to the present invention. FIG. 4 is a flowchart illustrating the operation of an output compensation device in an exemplary photovoltaic PV power generation system according to the present invention. FIG. 5 is a schematic diagram illustrating an internal power cutoff method according to the transmission of an emergency cutoff message through a gateway in an output compensation device of an exemplary photovoltaic PV power generation system according to the present invention. Specific details for implementing the invention
[0019] In the technical field to which this invention belongs, a method of installing a small-capacity DC-DC converter (DC optimizer) on each solar module is being developed to address the disadvantages (economic feasibility) of the micro-inverter method. This is a distributed module structure that uses a DC optimizer (distributed converter module) for DC-DC conversion on each PV module to perform primary DC step-up, and then collects the stepped-up DC power to perform secondary DC-AC conversion. This DC optimizer method divides the primary DC-DC converter, which was responsible for Maximum Power Point Tracking (MPPT) and step-up in the conventional centralized string inverter structure, into multiple small-capacity modules, converts each into a DC optimizer, and installs it on each solar module to perform Maximum Power Point Tracking (MPPT) control tailored to the conditions of each module. Therefore, similar to the micro-inverter method, the DC optimizer installed on each individual module can perform Maximum Power Point Tracking (MPPT) control, thereby enabling greater power generation. Since the DC optimizer is a DC-DC converter, it has the advantage of being significantly cheaper than a micro-inverter that converts DC to AC, costing less than half as much, and also has excellent efficiency.
[0020] While DC optimizers (distributed modular converters) have lowered unit costs and improved economic efficiency, they still have several drawbacks that need to be addressed. First, because they utilize a Full Power Processing (FPP) method to convert the total power output from solar panels, they require a minimum capacity of 400 Wdc or more; as the output of high-efficiency panels improves in the future, the capacity of the DC optimizer must also be increased. This contributes to higher supply costs from a supply chain management (manufacturing process) perspective. Furthermore, since DC optimizers maintain a series connection structure to enhance conversion efficiency, current bottlenecks persist due to reduced current output from shaded modules. Switching to a parallel structure would significantly worsen DC-DC conversion efficiency. Most importantly, because the FPP method performs power conversion even when panels are operating normally, conversion losses resulting from the addition of stages are unavoidable. Ultimately, while the use of a distributed system offers the potential for improved power generation efficiency compared to a method using large-capacity centralized power converters, it entails accepting a reduction in efficiency of several percent or more.
[0021] Accordingly, the present invention provides an output compensation device, power compensation device, or PV optimizer (hereinafter referred to as an output compensation device), which is a new photovoltaic power converter structure that is currently being researched to solve the aforementioned problems. The output compensation method according to the present invention includes a method of installing a bypass path in parallel to solve current bottlenecks, calculating the power difference (differential power) between each module and transmitting it as much as possible through a serial connection path, while processing the remainder (differential power) that cannot be processed due to the bottleneck through a parallel connection bypass path.
[0022] The output compensation method processes only the power difference between modules, i.e., differential power. Since it processes power with a smaller power capacity compared to the FPP method, which is a micro-inverter and DC optimizer method, it can lower costs and reduce conversion losses. An important point is that power conversion losses are proportional to the amount of power processed. For example, when processing 100W of power with a power converter having 90% efficiency (FPP), the loss is 10W, and when processing 20W of power (DPP), the loss is reduced to 2W. The output compensation method according to the present invention processes differential power (usually 1 / 4 or less), so it is a method with excellent cost and loss improvement effects.
[0023] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.
[0024] The present inventions are provided to more fully explain the invention to those skilled in the art, and the following examples may be modified in various different forms, and the scope of the invention is not limited to the following examples. Rather, these examples are provided to make the disclosure more faithful and complete and to fully convey the spirit of the invention to those skilled in the art.
[0025] Additionally, in the drawings below, the thickness or size of each layer is exaggerated for convenience and clarity of explanation, and like reference numerals in the drawings refer to like elements. As used herein, the term "and / or" includes any one of the listed items and all combinations of one or more thereof. Furthermore, in this specification, the meaning of "connected" refers not only to cases where Member A and Member B are directly connected, but also to cases where Member C is interposed between Member A and Member B so that Member A and Member B are indirectly connected.
[0026] The terms used herein are for describing specific embodiments and are not intended to limit the invention. As used herein, the singular form may include the plural form unless the context clearly indicates otherwise. Additionally, as used herein, "comprise, include" and / or "comprising, including" specify the presence of the mentioned features, numbers, steps, actions, parts, elements, and / or groups thereof, and do not exclude the presence or addition of one or more other features, numbers, actions, parts, elements, and / or groups.
[0027] Although terms such as "first," "second," etc. are used in this specification to describe various components, parts, regions, layers, and / or parts, it is obvious that these components, parts, regions, layers, and / or parts should not be limited by these terms. These terms are used solely to distinguish one component, part, region, layer, or part from another region, layer, or part. Accordingly, the first component, part, region, layer, or part described below may refer to the second component, part, region, layer, or part without departing from the teachings of the present invention.
[0028] Additionally, the microprocessor and / or other related device or component according to the present invention may be implemented using any suitable hardware, firmware (e.g., application-specific semiconductor), software, or a suitable combination of software, firmware, and hardware. For example, various components of the microprocessor and / or other related device or component according to the present invention may be formed on a single integrated circuit chip or on separate integrated circuit chips. Additionally, various components of the microprocessor may be implemented on a flexible printed circuit film, a tape carrier package, a printed circuit board, or on the same substrate as the microprocessor. Additionally, various components of the microprocessor may be processes or threads running on one or more processors in one or more computing devices, which may execute computer program instructions and interact with other components to perform the various functions mentioned below. Computer program instructions are stored in memory that can be executed in a computing device using a standard memory device, such as random access memory, for example. Computer program instructions may also be stored on other non-transitory computer-readable media, such as CD-ROMs, flash drives, etc. Additionally, those skilled in the art relating to the present invention should recognize that the functions of various computing devices may be combined with one another, integrated into a single computing device, or the functions of a specific computing device may be distributed across one or more other computing devices without departing from exemplary embodiments of the present invention.
[0029] FIG. 1 is a schematic diagram illustrating the configuration of a mesh-based wireless communication system in an exemplary photovoltaic PV power generation system (10) according to the present invention. As shown in FIG. 1, the exemplary photovoltaic PV power generation system (10) according to the present invention may include a plurality of photovoltaic modules (11) (or strings) connected in series, an inverter (12) connected to the output terminals of the plurality of photovoltaic modules (11), a plurality of output compensation devices (100) connected to each of the plurality of photovoltaic modules (11), and a gateway (13) that communicates wirelessly with the plurality of output compensation devices (100).
[0030] In some examples, the gateway (13) can be connected to the router (14) via Ethernet communication, and the router (14) can be connected to the solar PV power generation monitoring server (16) via the internet network (15).
[0031] In some examples, the inverter (12) can be connected to the router (14) via the RTU (17) (Remote Terminal Unit) in an RS485 manner.
[0032] In some examples, the number of solar modules (11) and the number of output compensation devices (100) may be the same. In some examples, each solar module (11) may be connected in series to another solar module (11) via an output compensation device (100) connected thereto. In some examples, each solar module (11) includes a Wi-Fi mesh module (110), so that wireless communication can be made between the gateway (13) or the multiple output compensation devices (100) via Wi-Fi.
[0033] Here, "Mesh" means a network or net, signifying that it is woven together in multiple branches. Therefore, Mesh Wi-Fi (110) (Wi-Fi) refers to Wi-Fi that is woven together in multiple branches. Unlike the generally known "Extended Wi-Fi," this Mesh Wi-Fi (110) enables bidirectional communication between each output compensation device (100), for example, by linking multiple output compensation devices (100) together. For example, multiple output compensation devices (100) can be grouped together to form one large Wi-Fi network. Since Wi-Fi communication with the gateway (13) and separate data transmission and reception occur between each output compensation device (100), communication latency is reduced, and communication speed at the gateway (13) can be increased through much more efficient communication. Additionally, the entire Mesh Wi-Fi (110) can be unified under a single SSID (Wi-Fi name). Therefore, the mesh Wi-Fi (110) can cover a wider range of wireless environments by installing an infinite number of nodes (output compensation devices (100)), and since data is transmitted and received through separate communication routes between each node (output compensation device (100)), it does not affect communication through each gateway (13), thereby optimizing communication speed. In addition, the mesh Wi-Fi (110) has a unified SSID (Wi-Fi name) even when using multiple output compensation devices (100). Furthermore, the mesh Wi-Fi (110) enables uninterrupted Wi-Fi communication through the other node even if, for example, one of two nodes becomes unable to communicate.
[0034] In some examples, the output compensation device (100) according to the present invention is an IoT communication based on a Wi-Fi mesh (110) that senses and controls data of a plurality of output compensation devices (100), and may be a mesh Wi-Fi based communication for solar panel monitoring and control that enables low-cost, miniaturized circuit design by integrating the Wi-Fi mesh (110) into the microprocessor (130) of the output compensation device (100).
[0035] In addition, as described above, the output compensation device (100) according to the present invention may apply a Wi-Fi mesh-based communication concept that enables overcoming wireless communication failures and long-distance communication through communication with multiple nodes rather than a single communication.
[0036] Additionally, the output compensation device (100) according to the present invention may include a Master / Slave module that groups output compensation devices (100) into string units, shares their status values with each other, and transmits them to a server (16) through a gateway (13). It may also include a string unit Wi-Fi mesh Master / Slave module that enables uninterrupted wireless communication by automatically switching the roles of master and slave according to the communication status of the output compensation device (100).
[0037] FIG. 2 is a block diagram illustrating the configuration of an output compensation device (100) in an exemplary photovoltaic PV power generation system (10) according to the present invention. As shown in FIG. 2, each output compensation device (100) may include a Wi-Fi mesh module (110), a sensing unit (120), a microprocessor (130), a PWM controller (140), a gate driver, and a power control module (150). In some examples, the output compensation device (100) may further include a power supply (160) and a watchdog (170).
[0038] The Wi-Fi mesh module (110) may be configured to communicate wirelessly via Wi-Fi between the gateway (13) and a plurality of output compensation devices (100), or between a plurality of output compensation devices (100). In some examples, the Wi-Fi mesh module (110) may be implemented by integrating with a microprocessor (130). Since the configuration and operation of such a Wi-Fi mesh module (110) have already been described above, a redundant description is omitted.
[0039] The sensing unit (120) can sense the input voltage, input current, and current output voltage of the solar module (11). To this end, the sensing unit (120) may include an input voltage sensor (121) that senses the input voltage of the solar module (11), an output voltage sensor (122) that senses the output voltage of the solar module (11), an input current sensor (123) that senses the input current of the solar module (11), and a temperature sensor (124) that senses the temperature of the solar module (11). The analog values sensed through the input voltage sensor (121), the output voltage sensor (122), the input current sensor (123), and the temperature sensor (124) can be converted into digital values through an analog-to-digital converter (125) and then input to a microprocessor (130).
[0040] The microprocessor (130) can collect data (e.g., input voltage, output voltage, input current, and temperature) from another output compensation device (100) through the Wi-Fi mesh module (110) and calculate the average output current of the other output compensation device (100). Here, the average output current of the other output compensation device (100) may be defined as a "reference average output current".
[0041] Additionally, the microprocessor (130) can calculate its "current output current" using the input voltage, input current, and current output voltage sensed through the sensing unit (120).
[0042] Additionally, the microprocessor (130) can compare the current output current and current output voltage with a preset maximum allowable current, a preset minimum allowable voltage, and the reference average output current described above to select one of the preset various operation modes and output a control signal according to the selected operation mode to the PWM controller (140).
[0043] The PWM controller (140) can generate a PWM (Pulse Width Modulation) signal according to the control signal of the microprocessor (130) and output it to the gate driver and power control module (150).
[0044] The gate driver and power control module (150) can control the output voltage and output current of itself (output compensation device (100)) according to the PWM signal of the PWM controller (140). In some examples, the gate driver (150) may be for controlling a GaN semiconductor switching element.
[0045] The power supply (160) can provide a DC voltage to the microprocessor (130), for example, approximately 3.3V to approximately 80V. The watchdog (170) can transmit a reset signal to the microprocessor (130) or receive a kick signal from the microprocessor (130).
[0046] In this way, the output compensation device (100) according to the present invention can share power production data of each solar module (11) with one another via Wi-Fi mesh-based wireless communication. Here, since the voltage entering the inverter (12) is connected in series, it can be the sum of the voltages of the solar modules (11), and the current can be the lowest value among the output currents of the solar modules (11). Therefore, in order to maximize the power input to the inverter (12), it is important to reduce the deviation of the output currents of the solar modules (11). Accordingly, the output compensation device (100) according to the present invention operates / controls in the following operation mode to maximize the power entering the inverter (12), and this is explained below.
[0047] FIG. 3 is a table summarizing the operation modes and descriptions of the output compensation device (100) in an exemplary photovoltaic PV power generation system (10) according to the present invention. As shown in FIG. 3, the output compensation device (100), specifically, the microprocessor (130), may include approximately 7 operation modes. Here, FIG. 1 and FIG. 2 are referenced together.
[0048] In some examples, the bypass mode may include a mode in which the power produced by the solar module (11) is transmitted directly to the inverter (12) without the intervention of the output compensation device (100).
[0049] In some examples, the CC mode may include a mode that outputs to the inverter (12) with a fixed current.
[0050] In some examples, the CV mode may include a mode that outputs to the inverter (12) at a fixed voltage.
[0051] In some examples, the MPPT mode may include a mode that outputs to the inverter (12) at maximum power by adjusting the voltage and current using a maximum power estimation algorithm.
[0052] In some examples, the CUP mode may include an operation mode that forcibly increases the current output to the inverter (12) when the output current is lower than that of other solar modules (11).
[0053] In some examples, the CDOWN mode may include an operation mode in which, when the output current is higher than that of other solar modules (11), the current output is forcibly lowered and the voltage is increased and output to the inverter (12).
[0054] In some examples, the RS mode may include a mode that receives a rapid cutoff command transmitted by the gateway (13) and forcibly cuts off the power supply to the inverter (12).
[0055] FIG. 4 is a flowchart illustrating the operation of an output compensation device (100) in an exemplary photovoltaic PV power generation system (10) according to the present invention. Here, FIG. 1, FIG. 2 and FIG. 3 are to be referenced together.
[0056] As illustrated in FIG. 4, the output compensation device (100), specifically / or, the microprocessor (130), can perform steps 1 through 5, and once started, steps 2 through 5 can be repeated.
[0057] Step 1: Start
[0058] When the solar module (11) is first operated, the output compensation device (100) can be configured to select a bypass mode and output a maximum voltage to the inverter (12).
[0059] Step 2: Sensing
[0060] The output compensation device (100) senses the input voltage, input current coming from the solar module (11), and the output voltage output through the output compensation device (100) through the input voltage sensor (121), input current sensor (123), and output voltage sensor (122).
[0061] Here, the output compensation device (100) can calculate the output current value using the values of the input voltage, input current, and output voltage.
[0062] Additionally, the output compensation device (100) can sense the board temperature of the output compensation device (100) using the temperature value sensed through the temperature sensor (124).
[0063] Step 3: Collect External Output Compensator Node Data
[0064] The output compensation device (100) collects data from another output compensation device (100) through the Wi-Fi mesh module (110). Additionally, the output compensation device (100) calculates the average output current of the other output compensation device (100).
[0065] Step 4: Set Operation Mode
[0066] In some examples, the output compensation device (100) changes to or selects the CDOWN mode described above when the current output current exceeds a preset maximum allowable current.
[0067] In some examples, the output compensation device (100) switches to or selects a bypass mode when the current output voltage is lower than a preset minimum allowable voltage.
[0068] In some examples, the output compensation device (100) changes to or selects CUP mode when the current output current is less than or equal to a set percentage of the reference average current of another output compensation device (100) node.
[0069] In some examples, the output compensation device (100) changes to or selects CDOWN mode when the current output current is greater than or equal to the reference average current of another output compensation device (100) node by a set percentage.
[0070] In some examples, the output compensation device (100) changes to or selects MPPT mode when the current output current is within a set percentage of the reference average current of other output compensation device (100) nodes.
[0071] In some examples, the output compensation device (100) changes to or selects RS mode when a rapid power cutoff command is received from the gateway.
[0072] Step 5: Control Step
[0073] In some examples, the output compensation device (100) can be controlled to transmit the power produced by the solar module (11) directly to the inverter (12) in bypass mode.
[0074] In some examples, the output compensation device (100) can control the output current value to be lowered by lowering the duty value of the gate driver (150) in CUP mode and output to the inverter (12).
[0075] In some examples, the output compensation device (100) can control the output current value to be increased by increasing the duty value of the gate driver (150) in CDOWN mode and output to the inverter (12).
[0076] In some examples, the output compensation device (100) can control the output to the inverter (12) in MPPT mode by increasing or decreasing the duty value of the gate driver (150) so that the value of the output power (=output voltage × output current) is higher than the previously calculated value.
[0077] In some examples, the output compensation device (100) can cut off power output to the inverter (12) by controlling the duty of the gate driver (150) in RS mode.
[0078] FIG. 5 is a schematic diagram illustrating an internal power cutoff method in which an emergency cutoff message is transmitted via a gateway (13) in an output compensation device (100) of an exemplary photovoltaic PV power generation system (10) according to the present invention. As shown in FIG. 5, the gateway (13) can transmit an emergency cutoff message to the output compensation device (100) of a specific photovoltaic module (11) via a Wi-Fi mesh module (110). Then, the output compensation device (100) that receives the emergency cutoff message turns off the connection switch (110A) so that the power output of the corresponding photovoltaic module (11) to the inverter is cut off.
[0079] The above description is merely one embodiment for implementing an output compensation device for improving the output of an exemplary photovoltaic PV power generation system according to the present invention. The present invention is not limited to the above-described embodiment, and the technical spirit of the present invention extends to the scope in which various modifications can be made by anyone with ordinary knowledge in the field to which the invention belongs, without departing from the gist of the invention as claimed in the following patent claims. Explanation of the symbols
[0081] 10; Solar PV power generation system 11; Solar module (or string) 12; inverter 13; Gateway 14; Router 15; Internet network 16; server 17; RTU 100; output compensation device 110; Wi-Fi mesh module 120; Sensing unit 121; Input voltage sensor 122; Output voltage sensor 123; Input current sensor 124; temperature sensor 125; Analog-to-Digital Converter 130; microprocessor 140; PWM controller 150; Gate driver and power control module 160; Power supply 170; Watchdog
Claims
Claim 1 A photovoltaic PV power generation system comprising: a plurality of photovoltaic modules connected in series; an inverter connected to the output terminals of the plurality of photovoltaic modules; a plurality of output compensation devices connected to each of the plurality of photovoltaic modules; and a gateway communicating with the plurality of output compensation devices, wherein each of the plurality of output compensation devices comprises: a Wi-Fi mesh module configured to wirelessly communicate via Wi-Fi between the gateway or the plurality of output compensation devices; a sensing unit that senses the input voltage and input current of the photovoltaic module and senses its own current output voltage; a microprocessor that collects data from other output compensation devices through the Wi-Fi mesh module to calculate a reference average output current, calculates its own current output current using the input voltage, input current, and current output voltage sensed through the sensing unit, selects an operating mode by comparing the current output current and the current output voltage with a maximum allowable current, a minimum allowable voltage, and a reference average output current, and outputs a control signal according to the selected operating mode; and a PWM controller that outputs a PWM (Pulse Width Modulation) signal according to the control signal of the microprocessor. An output compensation device comprising a gate driver and a power control module that control its own output voltage and output current according to the PWM signal of the PWM controller.