WO2015030453A1 - Micro converter apparatus for photovoltaic energy generation source and controlling method therefor - Google Patents

Abstract

The present invention relates to a micro converter apparatus for photovoltaic modules capable of minimizing an insertion loss and coping with a situation where an overcurrent flows on an inductor, and a controlling method therefor. The micro converter apparatus for photovoltaic modules comprises: a micro converter for varying the path of a current in accordance with a difference in power generated by the photovoltaic modules and then compensating for a current difference among the photovoltaic modules; and a string controller for controlling a duty cycle of the micro converter on the basis of the power generated by the photovoltaic modules outputted from the micro converter and then adjusting the voltage of the photovoltaic modules. The present invention implements at least two micro converters in one box and installs the box in each of at least two modules, and thus, the present invention can implement the minimum number of a micro converter box for adjusting the voltage of the photovoltaic modules and can cope with the situation where an overcurrent flows on an induct in real time.

Description

Micro converter device for solar energy generation source and control method

The present invention relates to a micro converter device for a photovoltaic energy generating source and a control method thereof.

In general, photovoltaic power generation system is a pollution-free and unlimited system of converting solar energy directly into electrical energy, which has recently been spotlighted as renewable energy.

The photovoltaic system is essentially equipped with a photovoltaic module (PV module), and maximum power point tracking (hereinafter referred to as 'MPPT') in the central inverter to increase the photovoltaic efficiency. Do this. Up to thousands of photovoltaic modules are connected to one inverter. Since the output voltage and current of one photovoltaic module is small, the voltage output from a string in which a plurality of photovoltaic modules are connected in series as the input of the inverter (increased output The output current (raised output current) from the plurality of strings connected in parallel with the voltage is supplied.

In this case, since the internal solar modules are connected in series, if one module is deteriorated and outputs less current than other modules in the vicinity, the entire string flows to the current value of the deteriorated solar module. A problem arises. In addition, in a structure in which a plurality of strings are connected in parallel, a problem arises in that the whole is lowered to the lowest voltage even when the voltages of the strings do not match.

The reason why the characteristics of a particular module in the string is deteriorated is due to shadows, dust, fallen leaves, characteristic changes due to deterioration between modules, and the like.

For example, a solar module changes its current-voltage and power-voltage characteristic curves as the amount of solar radiation changes, and if the shadow is partially shadowed inside the string, the shadowed solar modules follow this characteristic curve. The current value drops and thus the current across the string is determined based on the lowest current value.

On the other hand, in recent years, by mounting a micro-converter that performs the maximum power point tracking on a module basis, to some extent compensate for the deterioration of the characteristics of a particular module.

Conventional technology for a photovoltaic device using a micro converter is disclosed in Korean Patent Registration No. 10-1245827. According to the preceding document, in order to improve the energy efficiency and cost savings for the photovoltaic power generation system, each solar module (PV module) is provided with a micro converter, the environment / situation factors of real-time module unit in the micro converter In response to power / environmental monitoring.

FIG. 1 is a diagram illustrating a configuration of a micro converter system in which a maximum power point tracking device and a DC / DC converter are installed in a solar module in a cascade system.

In FIG. 1, reference numeral 10 denotes one solar module, reference numeral 11 denotes a junction box (J / B), reference numeral 12 denotes a micro-converter corresponding one-to-one with the junction box 11.

The micro-converter 12 receives 100% of the output power of the photovoltaic module 10 and adjusts the voltage of the photovoltaic module to be in a maximum power point (MPP) state, and serves to export the power as a string. At this time, the micro-converter 12 itself consumes 2 to 3% of energy. Therefore, in a situation where there is high insolation, no clouds, and no degradation between modules, the production power is lower than when no micro-converter is installed. This is called insertion loss.

In addition, the prior art as described above has a problem that the system price increases because the micro-converter must be installed per module in order to prevent deterioration of the characteristics of a particular module. For example, in the case of 1MW large-scale photovoltaic power plant, about 250 250W photovoltaic modules are used. As such, the micro-converter has a great impact on the system cost.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems, and to provide a micro-converter device for a photovoltaic module and a method of controlling the same, which minimize insertion loss and cope with overcurrent flow. will be.

Another object of the present invention is to provide a micro-converter device for a photovoltaic module and a method of controlling the same, by minimizing the number of installation of the micro-converter mounted to increase the output efficiency, thereby lowering the installation cost of the photovoltaic system.

Another object of the present invention is to reduce the micro-converter box required for the photovoltaic power generation system by making SOC (system on chip) the core function of the micro-converter and overlapping the micro-converter dedicated circuit in one SOC. The present invention provides a micro converter device for a solar module.

The micro-converter device for solar energy source according to one aspect of the present invention is connected to a plurality of solar energy generation source connected in series, the path of the current in accordance with the difference in the production power of the plurality of solar energy generation source A micro converter that compensates for the current deviation between the solar energy generating sources; And a string controller controlling the voltage of the solar energy generation source by controlling the duty cycle of the micro converter based on the production power of the solar energy generation source output from the micro converter.

Here, the micro converter may be connected in parallel with the solar energy generation source.

In addition, the micro-converter may further include a junction box which is combined with a corresponding solar energy generating source to serve as an interface for outputting the output of the corresponding solar energy generating source to another solar energy generating source.

In addition, the micro-converter may include an inductor for current deviation compensation, and a switch installed at one end of the inductor to set a current path.

The micro-converter also transmits voltage and current measurements of the solar energy generation source to the string controller, receives duty cycle control data and operation data transmitted from the string controller, and receives the received duty cycle control data. And a module controller configured to control a duty cycle of the switch or operate in a duty off mode based on the operation data.

The string controller may include: a communication module in communication with the micro converter to receive a voltage and current measurement value of a solar energy generation source and to transmit control data to the micro converter; A maximum power point calculator configured to calculate a maximum power point based on voltage and current values of each solar energy generation source received through the communication module; And a duty controller configured to transmit a duty cycle control signal to the micro converter according to the maximum power point calculated by the maximum power point calculator to adjust the voltage of the solar energy generating source. In this case, the duty controller compares the voltage and current values of each solar module with a reference value to determine whether the duty off and overcurrent, and transmits the duty off data to the micro converter in the duty off mode, the insertion loss Can be removed.

On the other hand, the micro-converter device for a solar energy source according to another aspect of the present invention includes a power controller for controlling the duty based on the maximum power point to follow to maintain a constant output of the solar energy source. The power controller may include a digital processor configured to generate a power control signal according to a maximum power point based first duty control signal based on a voltage detected directly from the solar energy generation source or a second duty control signal received from an external string controller; And an analog processor configured to provide a voltage detected from a solar energy generation source to the digital processor, and generate a control signal for driving an external switch according to a power control signal generated from the digital processor.

In this case, the power controller may be implemented in the form of a system on chip (SOC).

In addition, the micro-converter device may be arranged in parallel with at least two power controllers. In this case, the two or more power controllers can be operated independently by separating the power source and the ground, respectively.

The digital processing unit may further include: a filter for filtering and averaging the detected voltage and current of the solar energy generation source transferred from the analog processing unit; A host interface for receiving the second duty control signal transmitted from the string controller; A maximum power point tracking unit configured to calculate power based on the voltage and current of the solar energy generation source output from the filter, and generate a solar energy generation source voltage reference value by following the maximum power point based on the calculated power; A duty controller configured to output the first duty control signal such that the solar energy source voltage reference value generated from the maximum power point follower is equal to the actual solar energy source voltage; A multiplexer for selecting and outputting any one of the first duty control signal and the second duty control signal according to a mode of a solar energy generation source; And a PWM signal generator for generating a pulse width modulation (PWM) signal according to the duty control signal output from the multiplexer.

In this case, the micro-converter may include a plurality of communication modules configured to receive the second duty control signal transmitted from the string controller and transmit the received second duty control signal to the power controller; And a plurality of current regulators for compensating for the current deviation and setting the current path.

The micro converter may further include a communication module configured to receive duty data transmitted from the string controller; A main controller generating a duty control signal according to the duty data received from the communication module; A plurality of level shifters for adjusting a level of a duty control signal generated by the main controller and outputting the level control signal to the power controller; And a plurality of current adjusting units configured to compensate for current deviation and set a current path according to the control of the power controller.

On the other hand, the control method of the micro-converter device for a solar energy generation source according to a feature of the present invention

(a) the string controller following the maximum power point based on the voltage of the solar energy generating source transmitted from the micro converter, generating a duty cycle according to the followed maximum power point, and transmitting it to the micro converter; ; (b) When the inductor current inside the micro-converter is overcurrent, the string controller raises the total voltage to lower the current of the inductor or lowers the voltage of the solar energy generating source in which the output power falls, and generates the remaining solar energy. Transmitting a duty value to the micro-converter by calculating a new duty cycle in a direction of raising the voltage of the source; And (c) the string controller retrieving the voltage and current of the solar energy generating source and transmitting duty off data to the micro converter to duty off the micro converter when in the duty off mode.

According to an exemplary embodiment of the present invention, insertion loss can be minimized and coping can be performed even when overcurrent flows through the inductor.

In addition, according to an embodiment of the present invention there is an advantage that the installation cost of the photovoltaic power generation system can be lowered by minimizing the number of installation of the micro-converter mounted to increase the output efficiency.

In addition, according to an embodiment of the invention by reducing the micro-converter box required for the photovoltaic power generation system by making SOC (system on chip) core functions of the micro-converter, and by placing a dedicated micro-converter circuit in one SOC There is an advantage.

In addition, there is an advantage that can reduce the construction cost of the entire photovoltaic system by minimizing the micro converter box required for the photovoltaic system.

1 is a view showing the configuration of a conventional micro-converter system.

2 is a view showing the configuration of a cell, a sub module, and a module described in the embodiment of the present invention.

3 is a diagram illustrating an example of I-V characteristics of a cell, a submodule, and a module.

4 is a block diagram of a micro converter device for a solar module according to the first embodiment of the present invention.

FIG. 5 is a cable connection diagram of the micro-converter device shown in FIG. 3.

6 is a diagram illustrating in detail the configuration of the micro-converter according to the first embodiment of the present invention.

7 is a diagram illustrating a string controller according to a first embodiment of the present invention.

8 to 10 are diagrams showing a modification of the photovoltaic module micro device according to the first embodiment of the present invention.

FIG. 11 is a view showing a result of simulating a micro converter device for a solar module according to the first embodiment of the present invention.

12 is a diagram illustrating a process of controlling the module controller installed in the micro-converter according to the first embodiment of the present invention.

13 is a flowchart illustrating a process of controlling a micro converter in a string controller according to a first embodiment of the present invention.

14 illustrates a pattern of photovoltaic module currents when overcurrent flows through the inductor.

15 is a configuration diagram of a power control unit included in the micro-converter for the solar energy generation source according to the second embodiment of the present invention.

16 is a diagram illustrating in detail a digital processing unit and an analog processing unit of the power control unit according to the second embodiment of the present invention.

17 is a configuration diagram when a power control unit according to a second embodiment of the present invention is applied to a serial micro converter device.

FIG. 18 is a configuration diagram in which a power control unit according to a second embodiment of the present invention is applied to a power deviation processing type micro converter device.

19 is a configuration diagram of a modification in which the power control unit according to the second embodiment of the present invention is applied to a power deviation processing type micro converter device.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In the drawings, parts irrelevant to the description are omitted in order to clearly describe the present invention, and like reference numerals designate like elements throughout the specification.

Hereinafter, a micro converter device for a solar energy generation source and a control method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a diagram illustrating a configuration of a cell, a sub module, and a module described in an embodiment of the present invention, and FIG. 3 is a diagram illustrating I-V characteristics of a cell, a sub module, and a module.

According to an embodiment of the present invention, a plurality of solar cells (for example, 60 or 72) 40 are connected in series to one solar module 60. In the case of partial shadowing of multiple solar cells connected in series, all cells are limited by the output current due to the nature of the series connection. Therefore, the bypass diodes 70 are connected in parallel to each of the submodules 50 in which a predetermined number (for example, 20 or 24) cells are grouped. As a result, even in the case of partial shadows, the power generation of the photovoltaic module can be bypassed, and only the shadowed submodules can be bypassed, resulting in efficient power production.

According to the exemplary embodiment of the present invention shown in FIG. 2, 20 or 24 cells are connected in series to form one submodule, and three submodules having parallel connected bypass diodes are configured as one single module. However, the present invention is not limited thereto and may be configured by changing the number of cells constituting the submodule as necessary. For example, to reduce the number of bypass diodes, 60 cells are determined as one submodule, and one module has one submodule, or 60 submodules are connected by connecting bypass diodes in each cell. It is also possible to configure as a module.

As shown in FIG. 3, since the submodule is a series of one or more cells (called unit cells) in series, the current of the submodule is equal to the current of the unit cell and the magnitude of the submodule. The voltage is equal to the sum of the magnitudes of the voltages of the plurality of unit cells. Similarly, the voltage of one module is equal to the sum of the magnitudes of the voltages of the plurality of submodules, and the current of the module is equal to the current of one submodule.

Cells, sub-modules, and modules described in the embodiments of the present invention are all solar energy generating sources. Hereinafter, for convenience of description, a module or a sub module will be described as an example of a solar energy generation source, but the present invention is not limited thereto, and the present invention can be directly applied to a cell.

4 is a configuration diagram of the micro-converter device for a solar module according to the first embodiment of the present invention, Figure 5 is a cable connection diagram of the micro-converter device shown in FIG.

4 and 5, the micro converter device for a solar module according to the first embodiment of the present invention includes a junction box 120, a micro converter 130, and a string controller 140. Include.

The junction box 120 is combined with the solar module 110 to serve as an interface for outputting the output of the solar module 110 to other solar modules or other devices.

The micro-converter 130 serves to compensate for the current deviation between the solar modules by varying the path of the current according to the difference in the production power of the solar module 110. The micro converter 130 is connected in parallel with the solar module 110, and manages a plurality of solar modules. According to the first embodiment of the present invention, the micro-converter 130 is configured separately from the junction box 120.

The micro-converter 130 is an inductor (L3, L4), the switch (d4, / d4, d3, / d3) is installed at one end of the inductor to set the current path, and the module controller 131 for controlling the duty cycle of the switch It includes.

The string controller 140 adjusts the voltage of the solar module by controlling the duty cycle of the micro-converter 130 based on the production power of the solar module output from the micro-converter 130. do. The string controller 140 performs control in units of strings.

6 is a diagram showing in detail the configuration of the micro-converter 130 according to the first embodiment of the present invention.

As shown in FIG. 6, the micro-converter 130 according to the first embodiment of the present invention includes an inductor L3, L4, a switch d4, / d4, d3, / d3, a module controller 131, and a driver. 132, 133.

The inductors L3 and L4 serve to provide a bypass path for current deviation compensation, and the switches d4, / d4, d3, and d3 are installed at one end of the inductor L3 and L4 so that the current path ( That is, a bypass path through the inductor or a path directly connected between the solar modules) is set.

The module controller 131 transmits the voltage and current measurement values of the solar module to the string controller 140 and based on the duty cycle control data and the operation control data received from the string controller 140, the switch d4, / d3, d3, / d3) to control the duty cycle. In addition, the module controller 131 is connected between the two modules to operate by sending the power deviation of the two modules to the output through the path inside the module controller.

Specifically, the module controller 131 determines the voltage ratio of two modules connected to the module controller, and in a situation in which a mismatch between modules occurs, a power deviation that cannot be transmitted through a serial connection path between modules connected to the module controller 131 is determined. Bypass into the inductor path and add to the output of the string.

The drivers 132 and 133 drive the switches d4, / d3, d3 and / d3 in an on or off state under the control of the module controller 131. At this time, the switches d4 and d3 provided on the left side of the inductor and the switches / d4 and d3 provided on the right side of the inductor operate in opposite directions.

7 is a diagram illustrating a string controller 140 according to a first embodiment of the present invention.

As shown in FIG. 7, the string controller 140 according to the first embodiment of the present invention includes a communication module 141, a maximum power point follower 142, a duty controller 143, and a DC / DC converter 144. ).

The communication module 141 communicates with the micro-converter 130 to receive voltage and current measurement values of the solar module and transmits control data to the micro-converter 130.

The maximum power point follower 142 calculates a maximum power point MPP based on voltage and current values of each solar module received through the communication module 141.

At this time, according to the first embodiment of the present invention, the maximum power point tracking unit 142 calculates power based on the input voltage and current, and follows the maximum power point tracking, such as a commonly used P & 0 (Perturbation & observation) algorithm. The algorithm uses the algorithm to calculate the maximum power point. However, the present invention is not limited to using the P & O algorithm, and various other maximum power point tracking algorithms can be used.

The duty controller 143 adjusts the voltage of the solar module by transmitting a duty cycle control signal to the micro-converter 130 according to the maximum power point calculated by the maximum power point follower 142.

According to the first embodiment of the present invention, the duty controller 143 compares the voltage and current values of each of the solar modules with a reference value to determine whether the duty-off mode and overcurrent, and in the duty-off mode the micro-converter ( 130, the duty off data is transmitted to remove the insertion loss. Specifically, when the duty controller 143 compares the voltage and current values of the photovoltaic modules with the reference value and determines the overcurrent, the duty controller 143 increases the total string voltage while maintaining the duty cycle of the micro-converter 130. Reduce the current in the inductor, or lower the voltage on the shadowed module and increase the voltage on the remaining modules to lower the current in the inductor.

The DC / DC converter 144 adjusts the voltage to enable the solar module to follow the maximum power point. That is, in order to follow the maximum power point, the voltage across the string should be changed to the value selected by the maximum power point algorithm. The DC / DC converter 144 changes the voltage across the string to the value selected by the maximum power point algorithm. Let's do it.

The string controller 140 communicates with all micro converters in a string unit to collect information (voltage and current) and to control all micro converters based on the collected information. Hereinafter, only the control of one micro-converter 130 will be described for convenience of description.

According to the micro-converter device for a solar module according to the first embodiment of the present invention configured as described above, the output of the solar module 110 is connected in series as conventionally, the micro-converter 130 is a solar module 110 ) Is connected in parallel. This structure is such that when there is no difference in current between modules, the solar module 110 operates as if the micro converter 130 does not exist, and the micro converter 130 only operates when there is a difference in production power between the solar modules. By compensating for mismatched current by changing the path of the solar module output to bypass the inductor, the problem of the conventional cascade type micro-converter is improved.

For example, if all of the solar modules in the string output the best power under the same conditions and the currents are the same, the micro-converter enters the duty-off mode without power processing to minimize insertion loss. And if there is a difference in output power between photovoltaic modules in the string, the micro-converters create a new current path and handle it.

The operation of the photovoltaic module micro-converter device according to the first embodiment of the present invention is described in detail as follows.

First, as shown in FIG. 5, the micro converter device for a solar module according to the first embodiment of the present invention includes one micro converter 130 for every two solar modules (for example, PV5 and PV4). It is a form of binding. This can reduce the number of micro-converters compared to the conventional cascade method.

The module controller 131 provided in the micro-converter 130 measures the voltage and current of each solar module, and transmits it to the string controller 140 through an internal communication module (not shown). At this time, according to the first embodiment of the present invention, the communication module of the module controller 131 is implemented as a wireless communication module, but the present invention is not limited thereto and may be implemented as a wired communication module. In addition, when the module controller 131 transmits the voltage and current measurement values of the photovoltaic module to the string controller 140, the module controller 131 transmits the measured values and the unique number (ID) of the corresponding photovoltaic module together to provide the photovoltaic module. Separate. Thus, according to the first embodiment of the present invention, by assigning a unique number (ID) for each photovoltaic module, the string controller 140, which voltage and current measurement value easily received is the voltage, current of which photovoltaic module You will know.

The communication module 141 of the string controller 140 receives voltage and current measurement values of each photovoltaic module transmitted from the plurality of micro-converters 130 and transmits them to the duty controller 143. The duty controller 143 converts the input voltage and current measurement values into corresponding digital voltage and current values, and stores them in the internal memory (not shown) and transmits them to the maximum power point following unit 142.

The maximum power point follower 142 calculates a change amount of the digital measurement voltage and then follows the maximum power point based on the calculated change amount. Here, the maximum power point tracking may be used by adopting a maximum power point tracking method that is usually performed in a solar power installation. The maximum power point thus followed is transferred to the duty controller 143.

When the voltage controller and the current measurement value for each solar module are input, the duty controller 143 compares the current values of each module to determine the duty off mode of the solar module, extracts the difference, and based on this, It is determined whether the solar module has a duty-off mode. In this case, the condition of the duty-off mode is that all solar modules have the same current value due to the same environmental conditions. In this case, the DC-DC converters of all the micro-converters are duty-off, and the voltage and current values of each module are continuously Observe and return to normal mode if a change in current occurs.

As a result of the determination, in the duty off mode, the duty controller 143 generates operation control data (duty off data) and transmits it to the micro converter 130 through the communication module 141. At this time, operation control data is transmitted to virtually all micro-converters.

The module controller 131 in the micro converter 130 receives and analyzes operation control data. As a result of the analysis, if the operation control data is the duty-off data, the driving of the drivers 132 and 133 is turned off, and only the communication module and the voltage and current sensor module for performing communication with the string controller 140 operate, and the DC-DC The converter operates in a duty off state. When the driving of the drivers 132 and 133 is turned off, the switches d4, / d4, d3, and / d3 associated with them are all turned off, and thus the operation is not performed. That is, when the solar module is in a normal state, the micro converter is operated in the duty off mode, thereby minimizing insertion loss.

Meanwhile, the duty controller 143 of the string controller 140 searches for voltage and current values measured by each solar module to compensate for the difference in power output between the solar modules. A duty cycle for voltage regulation of each solar module is generated based on the maximum power point calculated in 142.

Here, the relation for generating the duty cycle is shown in Equation 1 below.

[Equation 1]

  Where L denotes the inductor, d denotes the duty cycle, and v denotes the measured voltage measured by the solar module.

When the duty cycle according to the output power difference between the solar modules is generated through Equation 1, the duty cycle is transmitted to the micro converter 130 through the communication module 141.

The module controller 131 in the micro-converter 130 receives it, drives the drivers 132 and 133 according to the received duty cycle, and operates the switches of one end of the inductor L3 and L4. At this time, two switches of one end of the inductor operate in opposite directions in normal operation. That is, when the switch d4 is turned on, the switch / d4 is turned off. On the contrary, when the switch d4 is turned off, the switch / d4 is turned on.

The operation of the switch and the inductor change the output path of the power line output from each solar module. According to the change of the output power path, the voltage of the solar module is optimally adjusted, so that compensation is performed according to the output power deviation of the solar module. In detail, in a situation where there is a mismatch between photovoltaic modules, a current having the least insolation flows in the existing current path (ie, a series connection path between modules), and a newly formed current compensation path (that is, through an inductor) In the bypassed path, the current flows by subtracting the existing string current from the maximum power output current of the individual module.

5 and 6, the photovoltaic module micro device according to the first embodiment of the present invention is a micro converter configured separately from the junction box. This case can be used to implement a photovoltaic power generation system by additionally mounting a micro converter to the already installed solar module.

Meanwhile, when the photovoltaic power generation system is installed from the beginning, a micro converter and a junction box may be integrally implemented as a modification of the photovoltaic module micro device according to the first embodiment of the present invention.

For example, as illustrated in FIG. 8, the micro converter and the junction box may be integrally implemented by embedding a micro converter in the junction box 160 that interworks with the solar modules PV1, PV2, and PVN. In this case, the overall operation is the same as that of the micro converter device implemented in FIGS. 4 and 5.

According to the modification illustrated in FIG. 8, a string controller 171 is embedded in the first junction box 170 of the string, and the other junction box 160 communicates with the string controller 171. 161 is built in. The module controller 161 operates in a duty-off state in the duty-off mode, and operates in a state of adjusting the voltage of the solar module according to the duty cycle when a difference in output power between the solar modules occurs. In addition, the module controller 161 also operates in a mode that reduces the overcurrent when the output power difference between the photovoltaic module is severe and an overcurrent flows in a specific inductor.

In addition, as another modification of the photovoltaic module micro device according to the first embodiment of the present invention, as illustrated in FIG. 9, a plurality of sub-modules 311, 312, 313 and the micro-converter 320 may be connected in a series-parallel state (ie, the micro-converter may be connected in parallel with the submodule and may be connected in series between the micro-converters). In FIG. 9, three sub-modules are coupled to one solar module in series, and four output terminals thereof are coupled to the junction box integrated micro-converter 320. In order to combine the four output terminals, the micro-converter 320 includes three inductors L20, L21, and L22 and two switches d20, / d22, respectively connected to both ends of the three inductors L20, L21, and L22. d21, / d21, d22, / d22).

In FIG. 9, reference numeral 321 denotes a module controller, and reference numeral 330 denotes a string controller 330. Since the functions and operations of the module controller 321 and the string controller 330 shown in FIG. 9 are almost the same as those of the module controller 131 and the string controller 140 described with reference to FIG. Omit.

The switch control method of the photovoltaic module micro device shown in FIG. 9 is the same as the switch control method of the photovoltaic module micro device according to the first embodiment of the present invention shown in FIGS. 4 and 5. When the micro-converter in the sub-module unit is implemented as described above, efficiency may be increased as compared to the micro-converter in the solar module unit. In this case, since the number of micro-converters increases compared to the solar module unit, it may cause a disadvantage that the cost increases. Therefore, it is desirable for the designer of the solar module power generation facility to design the solar power generation facility in consideration of this.

In addition, as another modified example of the solar module micro device according to the first embodiment of the present invention, as shown in FIG. Reference numerals 411, 412, and 413 denote submodules, and reference numeral 420 denotes micro converters. According to this structure, the micro-converter 420 operates only between the sub-modules 411, 412, and 413 inside the solar module. Therefore, when viewed from the outside, the structure is the same as a general cascade micro converter. This structure improves performance because it operates in a sub-module unit compared to a cascade of solar modules, and cables can be combined as simply as a cascade structure.

FIG. 11 is a diagram illustrating a simulation result of a photovoltaic module microconverter device according to a first embodiment of the present invention, and calculates a current value flowing through each photovoltaic module when a shadow of a portion of the photovoltaic module in the string is cast. It is. Specifically, FIG. 11 illustrates the result when two adjacent solar modules are shadowed when 8A is produced in a normal solar module and 6A is produced in a shadowed module.

As shown in FIG. 11, when the micro-converter device according to the first embodiment of the present invention is not applied, the current of all modules flows through the imp shade 6A, but according to the first embodiment of the present invention. When the micro-converter device is applied, the current deviation can be compensated, so that each module operates at the maximum power point, and the current value of the string shows the current of Isys (7.33A), which is the average value of each module current. These simulation results show that the micro-converter device according to the first embodiment of the present invention aims to improve efficiency in the photovoltaic power generation facility.

12 illustrates a process of controlling by a module controller installed in a micro-converter of the method for controlling a micro-converter device for a solar module according to the first embodiment of the present invention.

First, in step S11, the module controller in the micro-converter measures the voltage v _k and the current i _k of the solar module and reports it to the string controller.

In step S12, the measured current of each inductor i _Lk is compared with a preset maximum value max. When the current of each inductor is equal to or greater than the maximum value, the flow moves to step S13 to change the duty cycle d _k in the string controller. request. In this case, instead of the micro converter measuring the inductor current (i _Lk ) as a variation, the string controller calculates this to determine the flow of overcurrent to a specific inductor and sends a command to each micro inverter when a duty cycle change command is required. have.

Thereafter, in step S14, it is checked whether the changed duty cycle is received from the string controller, and when the changed duty cycle is received, the process moves to step S15 to change the duty cycle of the switch based on this.

In addition, when a new command is received from the string controller as in step S16 while the switch is operated with the received duty cycle or a new duty cycle is not received, the process moves to step S17 to perform an operation according to the command. Here, the new command may vary, and as an example, it may be a micro converter dutyoff command.

FIG. 13 is a flowchart illustrating a process of controlling a micro converter in a string controller in a method for controlling a micro converter device for a solar module according to a first embodiment of the present invention.

First, in a string controller that controls the micro-converter for adjusting the output path of the solar module in step S21, the specific micro-converter wakes up, and the voltage v _k of the solar module transmitted from the wake-up micro-converter Receive the current i _k .

After the above process is performed for all solar modules (S22), in step S23 the maximum power point is followed based on the received voltage (MPPT), and the duty cycle (d _k) according to the following maximum power point. ) And send it to the micro-converter.

Meanwhile, when some adjacent solar modules in the string are shadowed, overcurrent may flow in the inductor inside the adjacent micro converter. As such, there is a need for a countermeasure when overcurrent flows through a specific inductor.

To this end, in step S24, the current of each inductor is calculated by Equation 2 below.

[Equation 2]

Here, the inductor current as described above can be calculated by the string controller, but it is also possible to directly measure each micro-converter and transmit it to the string controller through the communication module.

Next, it is checked whether the current of the inductor calculated in step S25 is greater than or equal to a preset maximum value (max). When the current of the inductor is greater than or equal to the maximum value, the control unit moves to step S26 to perform a control operation to reduce the current of the inductor. do.

Here, if an overcurrent flows through a specific inductor, the string controller can respond with various policies. The simplest method is to shut down all microconverters, and the other method is to shut down only the microconverter, including the inductor from which the overcurrent has been detected.

In addition, the current of the inductor can be reduced by the following method.

From Equation 2, it can be seen that the current of the inductor i _Ln is determined by d _{L (n-1),} i _n, i _n-1, i _{L (n-2), and} d _n-1 . Therefore, because the string controller knows these values, it is possible to predict mathematically whether the current of the inductor flows above the rated value, and if it exceeds the rated value, the duty cycle of each module controller is left as it is, and the total voltage is increased little by little. Increasing the voltage of the module little by little in the direction of Voc can reduce the current in the inductor because less current flows.

As another method, it is possible to lower the voltage of a module with a low module current to allow more current to flow, and to increase the voltage of the remaining modules as the previous method, so that the current flows small. In this case, according to the newly calculated voltage value Since the duty cycle of each module changes, it must be sent to the microconverter.

14 is a diagram illustrating a pattern of solar module current when an overcurrent flows through the inductor. In other words, if overcurrent flows through a specific inductor, the photovoltaic modules show the shadows that the current is less. From this, when the overcurrent flows through an inductor, the solar module which became the cause is known.

Next, in step S27, it is checked whether the currents of all the solar modules are in the same duty-off mode, and when all the solar modules are in the duty-off mode, the duty is given to the micro-converter to go to step S28 to duty off the micro-converter. Off data will be sent. This duty-off data allows the micro-converter to operate in the duty-off mode, thereby minimizing insertion loss.

According to the first embodiment of the present invention described above, the string controller transmits the duty control data for controlling the duty cycle of the micro-converter to the module controller based on the production power of the solar module output from the micro-converter, the module Although the controller controlled the duty cycle based on the duty cycle data received from the string controller, each module produced without using the string controller and the module controller fixed the duty to a certain set value (for example 0.5) by itself. Fixed duty operation to compensate for current variations is also possible.

The fixed duty method is a method in which the module controller generates a fixed duty (for example, 0.5) by itself without using a string controller. The duty of the module controller determines the voltage ratio of the two connected modules. If the duty is fixed at 0.5, the voltages of the two modules are also fixed. Therefore, since the fixed duty operates at a fixed voltage near the maximum power point without following the maximum power point, the performance is lower than the method of following the maximum power point using the string controller. However, the fixed duty can be implemented at low cost because a string controller is not required and the technical implementation is simple.

The configuration in the case of using such a fixed duty scheme can be easily implemented by, for example, removing the string controller 140 from the structure shown in FIG. Even when the fixed duty method is used, power deviation can be compensated for through the newly formed current compensation path (that is, the path bypassed through the inductor) when there is a mismatch between the solar modules through the operation of the switch and the inductor.

Hereinafter, a micro converter device for a solar module according to a second embodiment of the present invention will be described with reference to FIGS. 15 to 19.

15 is a configuration diagram of a power control unit included in the micro-converter for a solar module according to the second embodiment of the present invention.

As shown in FIG. 15, the power control unit 200 included in the micro-converter according to the second embodiment of the present invention includes first to third power controllers 201, 202, and 203. Here, the first to third power controllers 201, 202, and 203 follow the maximum power point among the components of the micro-converter applied to the general photovoltaic power generation system, and control the duty based on the maximum power point to follow the photovoltaic module. SOC (System on chip) is a part to keep the output constant.

Here, since the internal configurations of the first to third power controllers 201, 202, and 203 are all the same, and the operations are the same, only the first power controller 201 will be described below for convenience of description.

Herein, the power control unit 200 according to the second embodiment of the present invention has been described as being composed of three power controllers. However, the present invention is not limited thereto. ), And the number of power controllers can be determined. When the determined number of power controllers is plural, they may be arranged in parallel.

At this time, each power controller operates independently from the power source and the ground (G). If the power controller and ground are separated and operated independently for each power controller, the number of connection of the solar modules can be freely adjusted when applied to an actual product. For example, when the maximum power controller is used, it can be combined with three solar modules, and when two power controllers are used, the two solar modules can be combined.

The first power controller 201 includes a first digital processor 210 and a first analog processor 240.

The first digital processor 210 generates a power control signal based on a maximum power point based duty control signal tracked from a voltage detected by the solar module or a duty control signal transmitted from a string controller (not shown).

The first analog processor 240 supplies the voltage detected by the solar module to the first digital processor 210 and outputs an external field effect transistor according to the power control signal generated from the first digital processor 210. A gate control signal for driving the FET) is generated.

In FIG. 15, reference numeral 220 denotes a second digital processor, reference numeral 230 denotes a third digital processor, reference numeral 250 denotes a second analog processor, and reference numeral 260 denotes a third analog processor.

FIG. 16 is a diagram illustrating the digital processor 210 and the analog processor 220 of the power controller 200 shown in FIG. 15 in detail.

As shown in FIG. 16, the first digital processor 210 includes a filter 211, a timer 212, a host interface 213, a multiplexer 216, a duty controller 215, and a maximum power point follower ( 214 and PWM signal generator 217.

The filter 211 filters and averages the detection voltage v1 and the current i1 of the photovoltaic module transmitted from the first analog processor 240.

The timer 212 periodically outputs voltage and current data averaged by the filter 211.

The host interface 213 transmits voltage and current data of the photovoltaic module periodically transmitted from the timer 212 to a string controller (not shown), and receives a duty control signal transmitted from the string controller.

The maximum power point follower 214 calculates power based on the voltage and current of the solar module output from the filter 211, and tracks the maximum power point MPP based on the calculated power. Generate a voltage reference value (PV voltage reference value).

The duty controller 215 outputs a duty control signal such that the voltage reference value of the solar module generated from the maximum power point follower 214 is equal to the voltage of the actual solar module.

The multiplexer 216 may include a duty control signal Duty 1 output from the host interface 213 and a duty control signal Duty 2 output from the duty controller 215 according to a mode of the solar module. Select one and print it out.

The PWM signal generator 217 generates a pulse width modulation (PWM) signal according to the duty control signal output from the multiplexer 216.

Meanwhile, the first analog processor 240 includes an analog / digital converter 241 and a FET driver 242.

The analog-to-digital converter 241 converts the analog voltage and current detected by the solar module into digital voltage and current data, and the FET driver 242 in the PWM signal generator 217 of the first digital processing unit 210. The gate control signal (D, / D) for driving the external field effect transistor (FET) is generated according to the generated PWM signal.

The operation of the power control unit according to the second embodiment of the present invention configured as described above will be described in detail as follows.

First, the power control unit 200 according to the second embodiment of the present invention is a conventional solar module type micro-converter device (hereinafter referred to as a "serial structure type micro-converter device") shown in FIG. The present invention is applicable to both the solar module type micro-converter device (hereinafter referred to as a power deviation processing micro-converter device) according to the first embodiment of the present invention.

Therefore, it is necessary to inform the power control unit 200 what the shape of the solar module micro-converter device is applied. To this end, the second embodiment of the present invention uses a signal called a mode. For example, a mode signal of "1" is set in the case of the micro-converter device of the power deviation processing type shown in FIG. 4, and "0" in the case of the micro converter device of the series structure type shown in FIG.

When the mode is a serial structure, an internally generated duty control signal is used instead of an externally acquired value (ie, a value transmitted from a string controller). The operation when the mode is a serial structure will be described as follows.

The analog-to-digital converter 241 of the first analog processing unit 240 converts the analog voltage Vpv and the current Ipv detected from the solar module into digital voltage data and current data corresponding thereto, thereby converting the first digital signal. It transfers to the processing unit 210.

The filter 211 of the first digital processor 210 filters and averages the transmitted voltage data and current data, and averages the averaged voltage data and current data by the timer 212, the maximum power point follower 214, and Transfer to duty controller 215.

The timer 212 regards the input voltage data and current data as voltage and current measurements of the corresponding solar module, and periodically transmits them to the host interface 213. The host interface 213 transmits periodically transmitted voltage and current data to a string controller (not shown) through communication.

The maximum power point tracking unit 214 calculates power based on the input voltage and current, and uses the maximum power point tracking algorithm such as a perturbation & observation (P & O) algorithm commonly used for maximum power point tracking. Follow the power point. The voltage reference value of the photovoltaic module is changed based on the maximum power point that is followed and transferred to the duty controller 215.

The duty controller 215 compares the voltage reference value transmitted from the maximum power point follower 214 with the voltage value of the photovoltaic module, and sets the duty value so that the voltage reference value of the photovoltaic module is equal to the voltage of the actual photovoltaic module. Calculate. The duty control signal Duty2 is transmitted to the multiplexer 216 based on the calculated duty value.

At this time, since the serial structure type mode selection signal is input to the multiplexer 216, the duty control signal Duty 2 output from the duty controller 215 is selected and transmitted to the PWM signal generator 217. The PWM signal generator 217 generates a PWM signal corresponding to the transmitted duty control signal and transmits the PWM signal to the FET driver 242 of the first analog processor 240. Accordingly, the FET driver 242 generates a gate driving signal for controlling the gate of the external FET switch to control the external FET switch, thereby adjusting the voltage of the solar module. Since the adjustment of the solar module is the same as the operation of the micro-converter applied to the conventional photovoltaic system, a detailed description thereof will be omitted.

On the other hand, when the mode is a power deviation processing type, the duty control value transmitted from the external string controller is used as it is without generating a duty control signal internally. In other words, the duty value received from the host interface 213 is transmitted to the multiplexer 216.

At this time, since the power deviation processing type selection signal is input to the multiplexer 216 as a mode signal, the duty control signal Duty 1 transmitted from the host interface 213 is selected and transmitted to the PWM signal generator 217. . The PWM signal generator 217 generates a PWM signal corresponding to the transmitted duty control signal and transmits the PWM signal to the FET driver 242 of the first analog processor 240. Accordingly, the FET driver 242 generates a gate driving signal for controlling the gate of the external FET switch to control the external FET switch, thereby adjusting the voltage of the solar module.

17 is a configuration diagram when a power control unit according to a second embodiment of the present invention is applied to a serial micro converter device.

The micro-converter 600 according to FIG. 17 includes a power control unit 200 for controlling output power of the plurality of solar modules PV1, PV2, and PV2 to generate power.

Herein, the power control unit 200 includes at least two power controllers 201, 202, and 203 composed of a digital processing unit and an analog processing unit. The two or more power controllers are provided in one micro converter box. In this case, the two or more power controllers operate independently by separating the power source and the ground, respectively.

In FIG. 17, reference numeral 210 denotes a first digital processor, 220 denotes a second digital processor, 230 denotes a third digital processor, 240 denotes a first analog processor, 250 denotes a second analog processor, and 260 denotes a third analog processor. The configuration and operation of the first digital processing unit 210 to the third digital processing unit 230 and the first analog processing unit 240 to the third analog processing unit 260 are the same as those of the attached FIG. In the following description, redundant description will be omitted.

Reference numerals 671, 672, and 673 denote current control units, respectively. The current regulators 671, 672, and 673 are composed of one inductor and two switches, and the two switches alternately perform turn-on and turn-off operations, and thus, the voltage and current applied to the inductor. Change your route.

The micro-converter device illustrated in FIG. 17 includes three power controllers 201, 202, and 203 serving as a micro-converter in one micro-converter 600, and include three solar modules PV1, PV2, PV3) can be controlled. Therefore, the number of micro-converter boxes can be reduced by one-third in the construction of the photovoltaic system, thereby lowering the total cost of the photovoltaic system.

FIG. 18 is a configuration diagram in which a power control unit according to a second embodiment of the present invention is applied to a power deviation processing type micro converter device.

When the power control unit shown in FIG. 15 is applied to the power deviation processing type micro-converter device, the micro-converter device for the photovoltaic module has a path of current depending on the difference in the production power of the plurality of photovoltaic modules PM1, PM2, PM3. It includes a micro converter 700 to compensate for the current deviation between the solar modules.

In this case, the micro-converter 700 receives a duty control signal transmitted from a power control unit 200 and a string controller (not shown) to control the output power of the plurality of solar modules PM1, PM2, PM3. A plurality of communication modules 710, 720, 730 to deliver to the power control unit 200, and a plurality of current control unit (740, 750, 760) to compensate for the current deviation and to set the current path.

Herein, the power control unit 200 includes at least two power controllers 201, 202, and 203 composed of a digital processing unit and an analog processing unit. The two or more power controllers are provided in one micro-converter box, and each power controller operates independently of a power source and a ground.

The operation in the case where the micro converter configured as described above is applied to the power deviation processing type micro converter device will be described as follows.

The first to third communication modules 710, 720, and 730 receive a duty control value for voltage adjustment of the photovoltaic module from a string controller (not shown) and transmit it to the power controller 200. The power control unit 200 uses the duty control value generated based on the duty control value received through the first to third communication modules 710, 720, and 730 or the voltage and current values detected from the internal solar module. To adjust the voltage of the solar module.

The first to third current controllers 740, 750, and 760 compensate for the current deviation and set the current path under the control of the power controller 200 to adjust the current. That is, one current controller 740 is provided with an inductor L for current deviation compensation and switches d1 and / d1 installed at one end of the inductor L to set a current path, and are controlled. In response to the data, the switches d1 and / d1 are controlled to adjust the current of the solar module.

18 is a structure in which one micro converter box can manage four solar modules PV1 to PV4. Therefore, the number of micro-converter boxes can be reduced to one-quarter in the construction of a photovoltaic system, further lowering the overall cost of the photovoltaic system.

19 is a configuration diagram of another modification in which the power control unit according to the second embodiment of the present invention is applied to a power deviation processing type micro converter device.

When the power control unit shown in FIG. 15 is applied to the power deviation processing type micro-converter, the micro-converter device for the photovoltaic module is configured to route the current according to the difference in the production power of the plurality of photovoltaic modules PV1, PV2, PV3. It includes a micro converter 800 that is variable to compensate for the current deviation between the solar modules.

In this case, the micro-converter 800 is a communication module 810 for receiving duty data transmitted from a string controller (not shown), and a main controller for generating a duty control signal according to the duty data received from the communication module 810. 820, a plurality of level shifters 870 and 880 for adjusting the level of the duty control signal generated by the main controller 820, the duty generated by the main controller 820 and the level shifters 870 and 880. A power control unit 200 for controlling the output power of the plurality of solar modules (PM1, PM2, PM3) in accordance with the control signal, a plurality of compensation for the current deviation in accordance with the control of the power control unit 200 and setting a current path And a current regulator 840, 850, 860.

Herein, the power control unit 200 includes at least two power controllers 201, 202, and 203 composed of a digital processing unit and an analog processing unit. In addition, the two or more power controllers 201, 202, and 203 are provided in one micro converter box, and each power controller operates independently by separating power and ground.

The operation in the case where the micro converter configured as described above is applied to the power deviation processing type micro converter device will be described as follows.

The communication module 810 receives a duty control value for adjusting the voltage of the solar module from a string controller (not shown) and transfers it to the main controller 820.

The main controller 820 transmits a duty control signal to the power control unit 200 according to the duty control value received from the communication module 810. In this case, since the power control unit 200 is composed of three power controllers 201, 202, and 203, one power controller 203 may output the duty control signals Cd3, v3, and i3 output from the main controller 820. The remaining power controllers 202 and 203 use the control signals Cd2, v2 and i2 output from the first level shifter 870 and the control signals Cd1 and v1 output from the second level shifter 880. , i1).

In this case, the control signals Cd2, v2, and i2 and the control signals Cd1, v1 and i1 are respectively output from the main controller 520 by the first level shifter 870 and the second level shifter 880. This signal is generated by synchronizing the duty control signal with the level.

Thereafter, the first to third current adjusting units 840, 850, and 860 compensate for the current deviation under the control of the power controller 200 and set a current path to adjust the current. That is, one current controller 840 includes an inductor L for current deviation compensation and switches d1 and / d1 installed at one end of the inductor L to set a current path, and are inputted to the control unit. In response to the data, the switches d1 and / d1 are controlled to adjust the current of the solar module.

The configuration as shown in FIG. 19 is a structure in which one micro-converter box can manage four solar modules in the same manner as the configuration in FIG. 18. Therefore, the number of micro-converter boxes can be reduced to one-quarter in the construction of a photovoltaic system, further lowering the overall cost of the photovoltaic system.

As described above, the principle of the present invention has been described through the embodiments or modifications of the present invention, but the present invention is not limited thereto, and various modifications are made within the scope of the claims and the detailed description of the invention and the accompanying drawings. It is possible to carry out by doing this, and this also belongs to the scope of the present invention.

That is, the principles of the present invention may include everything that can be implemented by suitable and reasonable modifications of the device or system. For example, the photovoltaic module mainly described in the embodiment of the present invention represents a representative example of a solar energy generation source, so in some cases, the solar module may be a solar submodule or a cell unit that is another solar energy generation source. It would be possible to broaden the scope and apply the same principles of the invention.

The present invention is applied to a photovoltaic device. In particular, the number of micro-converter boxes for adjusting the voltage of the photovoltaic module may be minimized, and the present invention may be effectively applied to a photovoltaic device for coping with an overcurrent flowing in the inductor.

Claims (24)

1. A micro converter connected to a plurality of solar energy generation sources connected in series and compensating for current deviation between the solar energy generation sources by varying a path of a current according to a difference in the production power of the plurality of solar energy generation sources; And

   And a string controller configured to adjust the voltage of the energy generating source by controlling the duty cycle of the micro converter based on the production power of the solar energy generating source output from the micro converter. Converter device.
2. The micro-converter device for solar energy source according to claim 1, wherein the micro-converter is connected in parallel with the solar energy source.
3. The method of claim 1, further comprising a junction box, coupled with the corresponding solar energy generating source, serving as an interface for outputting the output of the corresponding solar energy generating source to another solar energy generating source. Micro converter device for solar energy generation source.
4. The method of claim 1,

   The solar energy generating source is a solar module, the micro-converter device for a solar energy generating source.
5. The method of claim 1,

   The solar energy generating source is a solar sub-module or a solar cell micro-converter device for a solar energy generating source, characterized in that.
6. The method of claim 1, wherein the micro converter

   Inductors provide bypass paths for current deviation compensation

   A switch installed at one end of the inductor to set a current path;

   Transmit voltage and current measurements of the solar energy generation source to the string controller, receive duty cycle control data and operation data transmitted from the string controller, and based on the received duty cycle control data and the operation data And a module controller for controlling the duty cycle of the switch or operating in a duty off mode.
7. 7. The micro-converter device of claim 6, wherein the micro-converter further comprises a driver for driving the switch on or off under the control of the module controller.
8. The method of claim 7, wherein the module controller is

   If there is no mismatch of production power between the solar energy generating sources, a current flows through a series connection path between the solar energy sources, and there is a miss of production power between the solar energy generating sources. And if there is a match, controlling the current to flow through the bypass path through the inductor.
9. The method of claim 1, wherein the string controller

   A communication module in communication with the micro converter to receive voltage and current measurements of a solar energy generation source and to transmit control data to the micro converter;

   A maximum power point calculator configured to calculate a maximum power point based on voltage and current values of each solar energy generation source received through the communication module; And

   And a duty controller for transmitting a duty cycle control signal to the micro converter according to the maximum power point calculated by the maximum power point calculator to adjust the voltage of the solar energy source. Micro Converter Unit.
10. The method of claim 9,

    The string controller

    And a DC / DC converter for adjusting the voltage such that the solar energy generating source maintains the maximum power point following.
11. The method of claim 9, wherein the duty controller compares the voltage and current values of the respective solar energy generating sources with a reference value to determine whether the duty-off or over-current is present, and transmits the duty-off data to the micro converter in the duty-off mode. Microconverter device for solar energy generation sources, characterized by eliminating insertion loss.
12. 10. The method of claim 9, wherein the duty controller compares the voltage and current values of the respective solar energy generating sources with a reference value to determine the overcurrent, and increases the total voltage while maintaining the duty cycle of the micro converter to increase the current of the inductor. Micro converter device for a solar energy source, characterized in that for reducing.
13. The method of claim 9, wherein the duty controller compares the voltage and current values of each of the solar energy generating sources with a reference value and determines that the current is an overcurrent, and lowers the voltage of the first solar energy generating source and A micro-converter device for a solar energy source, characterized in that to reduce the current of the inductor by adjusting the duty to increase the voltage.
14. In the control method of the micro-converter apparatus for solar energy generation sources of any one of Claims 1-13,

    (a) the string controller following the maximum power point based on the voltage of the solar energy generating source transmitted from the micro converter, generating a duty cycle according to the followed maximum power point, and transmitting it to the micro converter; ;

    (b) When the inductor current inside the micro-converter is overcurrent, the string controller raises the total voltage to lower the current of the inductor or lowers the voltage of the solar energy generating source in which the output power falls, and generates the remaining solar energy. Transmitting a duty value to the micro-converter by calculating a new duty cycle in a direction of raising the voltage of the source; And

    (c) the string controller retrieving the voltage and current of the solar energy generating source and transmitting duty off data to the micro converter to duty off the micro converter when in the duty off mode. A control method of a micro-converter device for a solar energy source.
15. A microconverter device for controlling power of a plurality of solar energy generating sources,

    The micro-converter device is connected to a plurality of solar energy generating sources connected in series, and compensates for the current deviation between the solar energy generating sources by varying the path of the current according to the difference in the production power of the plurality of solar energy generating sources. Includes a micro converter,

    The micro converter

    An inductor providing a bypass path for current deviation compensation;

    A switch installed at one end of the inductor to set a current path;

    A driver for driving the switch to an on or off state; And

    Determining whether there is a mismatch in production power between the solar energy generating sources based on the voltage and current measurement values of the solar energy generating source, and transmitting a control signal to the driver based on the determination result. Micro-converter device for solar energy generation source comprising a module controller.
16. The method of claim 15,

    The module controller is fixed in duty,

    If there is no mismatch of production power between the solar energy generating sources, a current flows through a series connection path between the solar energy sources, and there is a miss of production power between the solar energy generating sources. And if there is a match, controlling the current to flow through the bypass path through the inductor.
17. A microconverter device for controlling power of a plurality of solar energy generating sources,

    The micro-converter device includes a power controller that controls the duty based on the maximum power point that is followed to maintain a constant output of the solar module.

    The power controller

    A digital processor configured to generate a power control signal according to a first duty control signal based on a maximum power point tracked from a voltage directly detected from the solar energy generation source or a second duty control signal received from an external string controller; And

    For the solar energy generation source including an analog processor for providing a voltage detected from the solar energy generation source to the digital processor, and generates a control signal for driving an external switch in accordance with the power control signal generated from the digital processor. Micro converter device.
18. 18. The micro-converter device of claim 17, wherein the power controller is implemented in the form of a system on chip (SOC).
19. 18. The micro-converter device for solar energy generation of claim 17, wherein the micro-converter device is arranged with at least two power controllers in parallel.
20. 20. The micro-converter device of claim 19, wherein the two or more power controllers operate independently from each other by a separate power source and ground.
21. The method of claim 17,

    The digital processing unit

    A filter for filtering and averaging the detected voltage and current of the solar energy generation source transmitted from the analog processor;

    A host interface for receiving the second duty control signal transmitted from the string controller;

    A maximum power point tracking unit configured to calculate power based on the voltage and current of the solar energy generation source output from the filter, and generate a solar energy generation source voltage reference value by following the maximum power point based on the calculated power;

    A duty controller configured to output the first duty control signal such that the solar energy source voltage reference value generated from the maximum power point follower is equal to the actual solar energy source voltage;

    A multiplexer for selecting and outputting any one of the first duty control signal and the second duty control signal according to a mode of a solar energy generation source; And

    And a PWM signal generator for generating a pulse width modulation (PWM) signal in accordance with the duty control signal output from the multiplexer.
22. The method according to any one of claims 17 to 21,

    The micro-converter is connected to a plurality of solar energy generation sources connected in series and compensates for the current deviation between the solar energy generation sources by varying the path of the current according to the difference in the production power of the plurality of solar energy generation sources. A microconverter device for a solar energy source.
23. The method of claim 22, wherein the micro-converter

    A plurality of communication modules configured to receive the second duty control signal transmitted from the string controller and transmit the received second duty control signal to the power controller; And

    And a plurality of current regulators for compensating for current deviation and setting a current path.
24. The method of claim 22, wherein the micro-converter

    A communication module for receiving the duty data transmitted from the string controller;

    A main controller generating a duty control signal according to the duty data received from the communication module;

    A plurality of level shifters for adjusting a level of a duty control signal generated by the main controller and outputting the level control signal to the power controller; And

    And a plurality of current regulators for compensating the current deviation and setting a current path under the control of the power controller.

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