Patent Publication Number: US-2023155547-A1

Title: Micro inverter for photovoltaic power generation and photovoltaic power generation system using the same and photovoltaic module array integrated the same

Description:
TECHNICAL FIELD 
     The present disclosure relates to a microinverter for photovoltaic power generation, a photovoltaic power generation system using the same, and a solar cell panel array integrated with the microinverter for photovoltaic power generation, and more specifically, to a microinverter for photovoltaic power generation, a photovoltaic power generation system using the same, and a solar cell panel array integrated with the microinverter for photovoltaic power generation, in which the microinverter is allowed to be easily attached to and detached from individual solar cell panels to facilitate maintenance of the microinverter, and performs Maximum Power Point Tracking (MPPT). 
     BACKGROUND ART 
     A photovoltaic (PV) power generation system is a system that converts sunlight into electric energy, and since there is no mechanical or chemical actions in the energy conversion process and thus the system structure is simple, its maintenance is simple, the lifespan is long as much as about 20 to 30 years, and it is environmentally friendly. 
     In addition, as the power generation scale may be diverse from a small capacity system of several kW to a large capacity system of several hundreds of kW, the photovoltaic power generation system attracts attention in the field of new and renewable energy. 
     In order to transmit power produced by the photovoltaic power generation to a system, a power converter capable of converting direct current to alternating current and tracking the maximum power operating voltage of a solar cell panel is required. The power converter may include a front-end DC-DC converter and a back-end DC-AC inverter. 
     Conventional photovoltaic power generation systems have a problem in that as several solar cell panels are connected to one power controller to reduce manufacturing cost, when generation of photovoltaic power is reduced in a plurality of solar cell panels, the total amount of power generation of the power controller abruptly decreases, and photovoltaic power generation systems integrated in a building, i.e., building integrated photovoltaic (BIPV) which attracts attention recently, have a more serious problem of decreasing power generation efficiency due to a partial shading phenomenon. 
     Accordingly, a new type of small inverters that install one inverter per solar cell module is applied recently. A new technique that emerges in the solar power inverter market, mainly in the US market, is the microinverter. The microinverter is not a centralized system that converts electricity collected by a solar cell panel array from direct current to alternating current, but a distributed system that converts direct current to alternating current in units of modules by installing an inverter in each individual solar cell panel (or each individual solar cell module). 
     However, even the distributed system has a problem in that since it is not easy to attach or detach an inverter by attaching the inverter as a power controller on the rear surface of a solar cell panel by performing silicon bonding, it is not easy to repair or replace a broken inverter. 
     DISCLOSURE 
     Technical Problem 
     Therefore, the present inventive concept has been made in view of the above problems, and it is an object of the present inventive concept to provide a microinverter for photovoltaic power generation, a photovoltaic power generation system using the same, and a solar cell panel array integrated with the microinverter for photovoltaic power generation, in which the problems of partial shading and device aging can be improved as each individual module has a maximum power point tracking (MPPT) control function, and maintenance such as repair, replacement or the like of an inverter can be easily performed by allowing the inverter to be easily attached to and detached from a solar cell panel. 
     Technical Solution 
     To accomplish the above object, according to one aspect of the present inventive concept, there is provided a microinverter for photovoltaic power generation, the microinverter comprising: a case lower plate formed in a plate shape; a case cover configured to cover the case lower plate; and a substrate installed on the case lower plate. 
     In addition, the substrate includes: a first conductor connected to a first solar cell module in parallel; a second conductor connected to a second solar cell module in parallel; a first switch connected to the first solar cell module and the first conductor in parallel; a second switch connected to the second solar cell module and the second conductor in parallel; a shuffling inductor connected between the first and second conductors and the first and second switches; a boost inductor connected to the first solar cell module, the first conductor, and the first switch; a third switch connected to the boost inductor, the second solar cell module, the second conductor, and the second switch; and an MPPT control unit for controlling operation of tracking a maximum power point on the basis of respective voltages of the first solar cell module and the second solar cell module, wherein the MPPT control unit may operate the first switch, the second switch, and the third switch. 
     In addition, the MPPT control unit may include: an MTTP unit for tracking a maximum power point on the basis of respective voltages of the first solar cell module and the second solar cell module; and a voltage adjustment unit for adjusting an output voltage of the MTTP unit. 
     In addition, the first switch and the second switch may operate on the basis of the output voltage of the MPPT unit, and the third switch may operate on the basis of an output voltage of the voltage adjustment unit. 
     In addition, the microinverter may further comprise: a DC voltage device connected to the third switch in parallel; and a rectifying device connected between the third switch and the DC voltage device. 
     In addition, a heat sink may be formed on a surface of the case cover. 
     In addition, the heat sink may be made of heat sink fins. 
     To accomplish the above object, there is provided a microinverter for photovoltaic power generation, the microinverter comprising: a fixed panel attached to a rear surface of a solar cell panel; and a detachable microinverter unit attached to and detached from the fixed panel by screw-coupling. 
     In addition, the fixed panel may be configured to include: a solar cell wire through hole formed for a solar cell wire, which draws out power of the solar cell panel, to pass through; and a plurality of fixing panel nut units formed in an edge area in a cylindrical column shape having a female screw to which a screw is coupled to fix the fixed panel by screw-coupling. 
     The detachable microinverter unit may be configured to include: an inverter box attached to and detached from the fixed panel by screw-coupling as a plurality of double nut units is formed along an edge; a substrate mounted inside the inverter box; and an inverter box cover that covers the inverter box. 
     To accomplish the above object, there is provided a solar cell panel array integrated with a microinverter for photovoltaic power generation, the inverter comprising: the microinverter for photovoltaic power generation; and one or more solar cell panels respectively having a microinverter integrally formed therein, wherein the solar cell panels are connected in parallel by the microinverters for photovoltaic power generation. 
     The solar cell panel may be configured to include a pair of first and second solar cell modules. 
     To accomplish the above object, there is provided a photovoltaic power generation system using a microinverter for photovoltaic power generation, the system comprising: the microinverter for photovoltaic power generation, a solar cell panel having a plurality of solar cell modules installed therein, and a support installed on a rear surface of the solar cell panel to support the solar cell panel, wherein the microinverter for photovoltaic power generation includes: a case lower plate formed in a plate shape; a case cover configured to cover the case lower plate; and a substrate installed on the case lower plate, wherein the substrate includes: a first conductor connected to a first solar cell module in parallel; a second conductor connected to a second solar cell module in parallel; a first switch connected to the first solar cell module and the first conductor in parallel; a second switch connected to the second solar cell module and the second conductor in parallel; a shuffling inductor connected between the first and second conductors and the first and second switches; a boost inductor connected to the first solar cell module, the first conductor, and the first switch; a third switch connected to the boost inductor, the second solar cell module, the second conductor, and the second switch; and an MPPT control unit for controlling operation of tracking a maximum power point on the basis of respective voltages of the first solar cell module and the second solar cell module, wherein the MPPT control unit operates the first switch, the second switch, and the third switch. 
     Advantageous Effects 
     The microinverter for photovoltaic power generation, the photovoltaic power generation system using the same, and the solar cell panel array integrated with the microinverter for photovoltaic power generation according to the present inventive concept provide an effect of remarkably facilitating maintenance of the microinverter and significantly reducing maintenance cost and time by allowing the microinverter to be easily attached to and detached from each individual solar cell panel. 
     In addition, the microinverter for photovoltaic power generation and the solar cell panel array integrated with the microinverter for photovoltaic power generation according to the present inventive concept provide an effect of minimizing degradation of power generation efficiency when sunlight is not radiated on some solar cell panels due to a shade or the like as the solar cell panels, of which the power generation efficiency has been lowered due to the shade or the like, do not affect power generation efficiency of the entire solar cell panel array by connecting the solar cell panels in parallel through the microinverters for photovoltaic power generation. 
     In addition, the microinverter for photovoltaic power generation is affected by the power conversion efficiency only as much as a difference in power at the maximum power point between the solar cell modules, not affected by the power conversion efficiency of the total power of the solar cell modules. Therefore, the microinverter for photovoltaic power generation and the solar cell panel array integrated with the microinverter for photovoltaic power generation according to the present inventive concept have an effect of ultimately increasing conversion efficiency in the entire system. 
     In addition, the photovoltaic power generation system using the microinverter for photovoltaic power generation can be directly coupled to a solar cell panel and a support, and has an effect of easily coupling the same. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    is a perspective view showing a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. 
         FIG.  2    is an exploded perspective view showing a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. 
         FIG.  3    is a view schematically showing a substrate of a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. 
         FIG.  4    is an exemplary view showing implementation of a microinverter substrate for photovoltaic power generation according to an embodiment of the present inventive concept. 
         FIGS.  5  and  6    are views showing the configuration of a photovoltaic power generation system using a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. 
         FIG.  7    is a view showing the configuration of a microinverter for photovoltaic power applied to  FIG.  6   . 
         FIG.  8    is a front perspective view (a) and a rear perspective view (b) showing a solar cell panel array  1  integrated with a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. 
         FIG.  9    is a perspective view showing a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. 
         FIGS.  10  and  11    are views showing the configuration of a photovoltaic power generation system using a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. 
         FIG.  12    is a view showing the configuration of a microinverter for photovoltaic power applied to the solar cell panel  20  of  FIG.  11   . 
         FIG.  13    is a perspective view showing a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. 
         FIG.  14    is an exploded perspective view showing a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. 
         FIG.  15    is a bottom perspective view showing the solar cell panel  20  of  FIG.  10   . 
         FIG.  16    is a perspective view showing a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. 
         FIG.  17    is an exploded perspective view showing a microinverter for photovoltaic power generation of  FIG.  16   . 
         FIG.  18    is a bottom perspective view showing a fixed panel  100 ′. 
         FIG.  19    is a bottom perspective view showing a detachable microinverter unit  200 ′. 
         FIG.  20    is a partial cross-sectional view showing the microinverter for photovoltaic power generation of  FIG.  16   . 
         FIG.  21    is a view schematically showing a substrate of a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. 
         FIG.  22    is an exemplary view showing implementation of a microinverter substrate for photovoltaic power generation according to an embodiment of the present inventive concept. 
     
    
    
       
     
       
         
           
               
             
               
                   
               
               
                 DESCRIPTION OF SYMBOLS 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
            
               
                 1: Solar cell panel array 
                   
               
               
                 5: Bus wire 
               
               
                 10: Microinverter for solar power 
               
               
                 generation 
               
               
                 20: Solar cell panel, solar cell plate 
               
               
                 21: First solar cell module 
               
               
                 23: Second solar cell module 
                 30: Support 
               
               
                 100: Case lower plate 
                 100′: Fixed panel 
               
               
                 101: Adhesive (silicon bond) 
                 110: Extended insertion unit 
               
               
                 120: Hinge-coupling unit 
                 130: Fixing panel nut unit 
               
               
                 140: Solar cell wire through hole 
                 180: Solar cell wire 
               
               
                 190: Inverter terminal socket unit 
                 191: Inverter terminal socket 
               
               
                   
                 substrate 
               
               
                 193: Inverter terminal socket 
                 200: Case cover 
               
               
                 200′: Detachable microinverter unit 
                 201: Inverter box cover 
               
               
                 202: Cover flange 
                 210: Heat sink paint layer 
               
               
                 211: Paint 
                 212: Protrusion 
               
               
                 213, 220: Self-assembled particle 
                 230, 215: Heat sink particle 
               
               
                 220′: Inverter box 
                 221: LED unit 
               
               
                 223: Communication antenna 
                 225: AC output port 
               
               
                 230′: Double nut unit 
                 231: Cover nut unit 
               
               
                 233: Fixing flange 
                 234: Through hole 
               
               
                 235: Substrate mounting nut unit 
                 250, 253: Near field communication 
               
               
                   
                 unit 
               
               
                 255: AC output port 
                 290: Inverter terminal socket unit 
               
               
                   
                 through hole 
               
               
                 293: Inverter terminal 
                 300, 700: Substrate 
               
               
                 310: First conductor 
                 320: Second conductor 
               
               
                 330: First switch 
                 340: Second switch 
               
               
                 350: Shuffling inductor 
                 360: Boost inductor 
               
               
                 370: Third switch 
                 380: DC voltage device 
               
               
                 390: Rectifying device 
                 410: First solar cell module 
               
               
                 420: Second solar cell module 
                 S: Screw 
               
               
                   
               
            
           
         
       
     
     DETAILED DESCRIPTION 
     In describing the present inventive concept below, when it is determined that the detailed description of a related well-known function or configuration may unnecessarily obscure the gist of the present inventive concept, the detailed description thereof will be omitted. 
     Since the embodiments according to the concept of the present inventive concept may make various changes and have various forms, specific embodiments will be illustrated in the drawings and described in detail in this specification or application. However, it should be understood that this is not intended to limit the embodiments according to the concept of the present inventive concept to specific disclosed forms, and the present inventive concept includes all changes, equivalents and substitutes included in the spirit and scope of the present inventive concept. 
     When a component is referred to as being “connected” or “coupled” to another component, it should be understood that the component may be directly connected or coupled to another component, but other components may exist therebetween. On the other hand, when a component is referred to as being “directly connected” or “directly coupled” to another component, it should be understood that no other components exist therebetween. Other expressions describing the relationship between components such as “between” and “immediately between” or “adjacent to” and “directly adjacent to”, and the like should be interpreted in the same way. 
     The terms used in this specification are used only to describe specific embodiments, and are not intended to limit the present inventive concept. A singular expression includes a plural expression unless the context clearly dictates otherwise. It should be understood that in this specification, the terms such as “comprise” or “have” are intended to designate presence of embodied features, numbers, steps, operations, components, parts, or a combination thereof, and do not preclude in advance the possibility of presence or addition of one or more other features, numbers, steps, operations, components, parts, or a combination thereof. 
     Hereinafter, a microinverter for photovoltaic power generation according to the present inventive concept will be described in detail with reference to the drawings. 
       FIG.  1    is a perspective view showing a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept,  FIG.  2    is an exploded perspective view showing a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept, and  FIG.  3    is a view schematically showing a substrate of a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. 
     First, referring to  FIGS.  1  and  2   , a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept is configured to include a case lower plate  100  formed in a plate shape; a case cover  200  configured to cover the case lower plate  100 ; and a substrate  300  installed on the case lower plate  100 . 
     Referring to  FIG.  3   , the substrate  300  is configured to include a first conductor  310  connected to a first solar cell module  410  in parallel; a second conductor  320  connected to a second solar cell module  420  in parallel; a first switch  330  connected to the first solar cell module  410  and the first conductor  310  in parallel; a second switch  340  connected to the second solar cell module  420  and the second conductor  320  in parallel; a shuffling inductor  350  connected between the first and second conductors  310  and  320  and the first and second switches  330  and  340 ; a boost inductor  360  connected to the first solar cell module  410 , the first conductor  310 , and the first switch  330 ; a third switch  370  connected to the boost inductor  360  and also connected to the second solar cell module  420 , the second conductor  320 , and the second switch  340 ; and an MPPT control unit  500  for controlling operation of tracking a maximum power point on the basis of respective voltages of the first solar cell module  410  and the second solar cell module  420 . 
     In addition, at this point, it may be configured to operate the first switch  330 , the second switch  340 , and the third switch  370  by the MPPT controller. The MPPT (Maximum Power Point Tracking) means tracking a maximum power point, which is widely used in photovoltaic power generation recently. 
     The MPPT may obtain maximum power by appropriately adjusting the load according to external conditions. The point at which the maximum power is transmitted is called as a maximum power operating point, and the maximum power operating point changes according to external conditions such as solar radiation, temperature, and the like. 
     In the present inventive concept, MPPT control is performed by the MPPT control unit  500 , and as an MPPT control method, there is a Perturb &amp; Observe (P&amp;O) method. The P&amp;O method is a method of finding the maximum power operating point by periodically increasing and decreasing the output voltage of the solar cell module and comparing previous output power with current output power. The P&amp;O method has an advantage in that there is no loss of solar cells as the maximum power point is stable in a situation where solar radiation gradually changes. 
     Additionally, a solar junction box including bypass diodes may be installed in the first conductor  310  and the second conductor  320  of the microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. The solar junction box may prevent reverse current caused by an abrupt change in sunlight. In other words, the solar junction box may prevent damage to the solar cell panel. 
     In summary, the solar junction box may perform the function of a junction box mounted on an existing solar cell module. 
     In the present inventive concept, as shown in  FIG.  3   , the substrate  300  may be configured to include a first conductor  310  connected to a first solar cell module  410  in parallel; a second conductor  320  connected to a second solar cell module  420  in parallel; a first switch  330  connected to the first solar cell module  410  and the first conductor  310  in parallel; a second switch  340  connected to the second solar cell module  420  and the second conductor  320  in parallel; a shuffling inductor  350  connected between the first and second conductors  310  and  320  and the first and second switches  330  and  340 ; a boost inductor  360  connected to the first solar cell module  410 , the first conductor  310 , and the first switch  330 ; a third switch  370  connected to the boost inductor  360  and also connected to the second solar cell module  420 , the second conductor  320 , and the second switch  340 ; and an MPPT control unit  500  for controlling operation of tracking a maximum power point on the basis of respective voltages of the first solar cell module  410  and the second solar cell module  420 . 
     In addition, the substrate may be configured to include a DC voltage device  380  connected to the third switch  370  in parallel; and a rectifying device  390  connected between the third switch  370  and the DC voltage device  380 . 
       FIG.  4    is an exemplary view showing implementation of a microinverter substrate for photovoltaic power generation according to an embodiment of the present inventive concept, and the configuration of the substrate  300  as described above may be implemented as shown in  FIG.  4   . 
     In the present inventive concept, the substrate  300  operates in a buck mode or a boost mode, and determines a voltage duty ratio of the first solar cell module  410  and the second solar cell module  420 . At this point, the buck mode or the boost mode of the substrate  300  is determined according to the direction of inductor current I shuff  of  FIG.  4   . For reference, it means that the output voltage is lower than the input voltage when the substrate  300  operates in the buck mode, and the output voltage is higher than the input voltage when the substrate  300  operates in the boost mode. 
     In the present inventive concept, the sum of the voltages of the first solar cell module  410  and the second solar cell module  420 , i.e., the sum of voltage PV 1  and voltage PV 2 , becomes the input voltage. In the present inventive concept, the maximum power point may be tracked by adjusting deviation of current with a differential power, and since voltage fluctuation in the first solar cell module  410  affects the second solar cell module  420 , the sum of the voltages of the first solar cell module  410  and the second solar cell module  420  becomes the input voltage. 
     In addition, in the present inventive concept, after sensing the voltage and current values of the first solar cell module  410  and the second solar cell module  420 , the maximum power points of the first solar cell module  410  and the second solar cell module  420  may be calculated in the P&amp;O method, and the duty ratio of the first solar cell module  410  and the second solar cell module  420  may be determined through a direct-duty ratio technique. In addition, the command voltage of all solar cell modules including the first solar cell module  410  and the second solar cell module  420  may be applied to V dc . 
     In addition, in the microinverter for photovoltaic power generation according to the present inventive concept, the MPPT control unit  500  may be configured to include an MPPT unit  510  for tracking the maximum power point on the basis of respective voltages of the first solar cell module  410  and the second solar cell module  420 ; and a voltage adjustment unit  520  for adjusting the output voltage of the MTTP unit  510 . 
     In addition, at this point, the first switch  330  and the second switch  340  may be configured to operate on the basis of the output voltage of the MPPT unit  510 , and the third switch  370  may be configured to operate on the basis of the output voltage of the voltage adjustment unit  520 . 
     Here, V con , which is the output voltage of the MPPT unit  510 , may be expressed as shown in [Equation 1]. 
     
       
         
           
             
               
                 
                   
                     V 
                     con 
                   
                   = 
                   
                     PV 
                     ⁢ 
                     1 
                     ⁢ 
                     _ref 
                     * 
                     
                       1 
                       
                         
                           PV 
                           ⁢ 
                           1 
                           ⁢ 
                           _ref 
                         
                         + 
                         
                           PV 
                           ⁢ 
                           2 
                           ⁢ 
                           _ref 
                         
                       
                     
                   
                 
               
               
                 
                   [ 
                   
                     Equation 
                     ⁢ 
                         
                     1 
                   
                   ] 
                 
               
             
           
         
       
     
     For reference, in  FIG.  4   , V B  is the boost input voltage, I string  is the main string current, V dc  is the DC link, L S  is the inductance of the shuffling inductor  350 , and L B  is the inductance of the boost inductor  360 . 
     As the substrate  300  is configured as described above, the microinverter for photovoltaic power generation according to the present inventive concept may endure of power an amount smaller than that of a conventional photovoltaic inverter that endures output of all the solar cell modules. That is, since the microinverter of the present inventive concept is affected by the power conversion efficiency only as much as a difference in power at the maximum power point between the solar cell modules, not affected by the power conversion efficiency of the total power of the solar cell modules, the conversion efficiency in the entire system finally increases. 
     Additionally, referring to  FIGS.  21  and  22   , in the microinverter for photovoltaic power generation according to the present inventive concept, the substrate  700  may be connected to one solar cell module  430 . 
     Describing in more detail, the substrate  700  may be configured to include a change detection sensor unit  710 , an internal power supply unit  720 , a PWM/MPPT controller  730 , a first protection controller  740 , a near field communication unit  250 , a DC boost unit  750 , a second protection controller  760 , and an AC inverter unit  770 . 
     The change detection sensor unit  710  may be connected to the solar cell module  430  to check the state of the solar cell module  430  at all times. In addition, the change detection sensor unit  710  may recognize a short circuit of the input of the solar cell module  430 , measure a voltage value, and measure a temperature or the like of the surrounding environment. 
     The internal power supply unit  720  may supply power of DC 10V, 5V, 3.3V or the like to the change detection sensor unit  710 , the PWM/MPPT controller  730 , the first protection controller  740 , the near field communication unit  250 , the DC boost unit  750 , the second protection controller  760 , and the AC inverter unit  770 . 
     The PWM/MPPT controller  730  may operate a PWM or MPPT function using a P&amp;O algorithm. 
     The first protection controller  740  may receive measurement values from the change detection sensor unit  710  and protect the solar cell module  430  from damage of external input power. 
     The near field communication unit  250  may transmit information such as the current state of the microinverter, power production performance and the like to the outside. In addition, when a failure or an error occurs in a solar cell panel  20 , the microinverter  10  transmits an identifier for identifying the solar cell panel  20  and information on the type of the failure or error to an external control center, a manager computer, an alarm device, or the like through the near field communication unit, so that the solar cell panel  20  in which the failure or error has occurred may be easily identified and handled. 
     The DC boost unit  750  may boost DC 50V input from the solar cell module  430  to DC 400V for conversion to AC 220V. 
     The second protection controller  760  may recognize power failure, disconnection, overvoltage, or the like for protection of the AC inverter unit  770 , and stop generation of the microinverter when a problem occurs in an externally connected power source. 
     The AC inverter unit  770  may convert DC 400V to AC 220V and supply AC 220V to the outside. In addition, the AC inverter unit  770  may include a power switch  771 , a rectifying unit  772 , an AC inverter  773 , an AC connection inverter  774 , and a grid power unit  775 . 
     The power switch  771  may be connected to external AC 220V to protect an external circuit (grid) and the AC inverter  773  only when the internal boost of the AC inverter  773  is sufficiently achieved. In other cases, the power switch  771  may be separated from the grid. 
     The rectifying unit  772  may smooth the DC power boosted to DC 400V into complete and stable DC power for inverting, and supply the complete and stable DC power to the AC inverter  773 . 
     The AC inverter  773  may convert DC 400V to AC 220V. 
     The AC connection inverter  774  may be used to safely connect AC 220V of the grid to the AC inverter  773 . 
     The grid power unit  775  may be an external part of a meter connected to AC 220V of the grid. 
       FIGS.  5  and  6    are views showing the configuration of a photovoltaic power generation system using a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept, and  FIG.  7    is a view showing the configuration of a microinverter for photovoltaic power applied to  FIG.  6   . 
     Referring to  FIGS.  5  and  6   , a photovoltaic power generation system using a microinverter for photovoltaic power generation according to the present inventive concept is configured to include a microinverter  10  for photovoltaic power generation, a solar cell panel  20  having a plurality of solar cell modules installed therein, and a support  30  installed on the rear side of the solar cell panel  20  to support the solar cell panel  20 .  FIG.  5    shows the front side of the solar cell panel  20 , and  FIG.  6    shows the back side (rear side) of the solar cell panel  20  and the support  30 . 
     That is, in the photovoltaic power generation system using a microinverter for photovoltaic power generation according to the present inventive concept, the microinverter  10  for photovoltaic power generation is configured to include a case lower plate  100  formed in a plate shape; a case cover  200  configured to cover the case lower plate  100 ; and a substrate  300  installed on the case lower plate  100 . The substrate  300  is configured to include a first conductor  310  connected to a first solar cell module  410  in parallel; a second conductor  320  connected to a second solar cell module  420  in parallel; a first switch  330  connected to the first solar cell module  410  and the first conductor  310  in parallel; a second switch  340  connected to the second solar cell module  420  and the second conductor  320  in parallel; a shuffling inductor  350  connected between the first and second conductors  310  and  320  and the first and second switches  330  and  340 ; a boost inductor  360  connected to the first solar cell module  410 , the first conductor  310 , and the first switch  330 ; and a third switch  370  connected to the boost inductor  360  and also connected to the second solar cell module  420 , the second conductor  320 , and the second switch  340 . In addition, at this point, it may be configured to operate the first switch  330 , the second switch  340 , and the third switch  370  by the MPPT controller. 
     In addition, in the present inventive concept, the case lower plate  100  may be configured to include an extended insertion unit  110  extended from the case lower plate  100  toward the outside; and a hinge-coupling unit  120  hinge-coupled to the extended insertion unit  110  to be rotatably installed, so that the extended insertion unit  110  may be insert-coupled between the solar cell panel  20  and one side of the support  30 , and the hinge-coupling unit  120  may be rotated and bolt-coupled on the other side of the support  30 . 
       FIG.  8    is a front perspective view (a) and a rear perspective view (b) showing a solar cell panel array  1  integrated with a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept,  FIG.  9    is a perspective view showing a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept,  FIG.  2    is an exploded perspective view showing a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept, and  FIG.  3    is a functional block diagram showing up to the front end of a converter performing MPPT control and DC boosting for AC conversion of the microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. 
     As shown in  FIG.  8   , the solar cell panel array  1  integrated with the microinverter includes solar cell panels  20 , and microinverters  10  for photovoltaic power generation integrally formed in the solar cell panels, and the solar cell panels  20  may be configured to be connected to each other in parallel as the microinverters  10  are connected to the bus wire  5  in parallel. 
     As described above, as the solar cell panels  20  are connected in parallel through the bus wire  5 , the influence on the power generation efficiency of the entire solar cell panel array  1  is minimized even when specific solar cell panels  20  constituting the solar cell panel array  1  are not irradiated with sunlight due to a shade or the like. Generally, compared with a case of connecting the solar cell panels  20  in series, in which the output of the entire solar cell panel array  1  is limited to the power generated by the solar cell panels  20  not irradiated with sunlight due to a shade or the like, or driving of the solar cell panel array  1  is stopped, the problems that occur when the solar cell panels  20  are connected in series do not occur when the solar cell panels  20  are connected in parallel. 
     In addition, the solar cell panels  20  are configured to include a pair of first and second solar cell modules  410  and  420 , and the microinverter  10  is formed to be integrated with the solar cell panel  20  so that the maximum power point of each of the first and second solar cell modules  410  and  420  may be tracked by adjusting deviation of current of the first and second solar cell modules  410  and  420  with a differential power to convert the power generated by the solar cell panel into AC power and output the AC power. 
     Referring to  FIGS.  2  and  9   , in order to perform tracking of the maximum power point described above, the microinverter  10  for photovoltaic power generation according to an embodiment of the present inventive concept is configured to include a case lower plate  100  formed in a plate shape; a case cover  200  configured to cover the case lower plate  100 ; and a substrate  300  installed on the case lower plate  100 . 
     Since the case lower plate  100 , the case cover  200  configured to cover the case lower plate  100 , and the substrate  300  installed on the case lower plate  100  are the same as those described above, detailed description thereof will be omitted. 
     In  FIGS.  3  and  4   , the DC voltage device  380  or V DC  may be a booster or a boosting device such as a chopper circuit or the like for boosting DC power to DC 400V or the like before AC conversion. 
       FIGS.  10  and  11    are views showing the configuration of a solar cell panel  20  integrated with a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept, and  FIG.  12    is a view showing the configuration of a microinverter  10  for photovoltaic power generation applied to the solar cell panel  20  of  FIGS.  10  and  11   . 
     Referring to  FIGS.  10  and  11   , the solar cell panel  20  integrated with a microinverter for photovoltaic power generation according to the present inventive concept is configured to include a microinverter  10  for photovoltaic power generation, a pair of solar cell modules  410  and  420 , and a support  30  installed on the back side of the solar cell panel  20  to support the solar cell modules  410  and  420 .  FIG.  6    shows the front side of the solar cell panel  20 , and  FIG.  7    shows the back side (rear side) of the solar cell panel  20 , the microinverter  10 , and the support  30 . 
     The microinverter  10  of the configuration described above may be configured to further include a near field communication unit  250  such as Wi-Fi, Bluetooth or the like as shown in  FIGS.  11  and  12   . In the case of  FIGS.  11  and  12   , it is shown that a Wi-Fi communication module having a Wi-Fi antenna  253  is configured as the near field communication unit  250 . According to the configuration of the near field communication unit  250  as described above, the microinverter  10  transmits an identifier for identifying a corresponding solar cell panel  20  and information on a failure or error type to an external control center, a manager computer, an alarm device, or the like when a failure or an error occurs in the solar cell panel  20  due to a shade or the like, so that the solar cell panel  20  in which the failure or error has occurred may be easily identified and handled. 
     Describing with reference to  FIG.  9    again, the case cover  200  may be provided with a heat sink paint layer  210  for releasing heat generated inside the microinverter to the outside. 
     The heat sink paint layer  210  is configured to include a paint  211 , self-assembled particles  220 , and heat sink particles  230 . 
     The paint  211  may be a paint having characteristics such as moisture resistance, heat resistance, flame retardancy, fire resistance, and insulation, in which organic binders, lacquer-based resins, diluents, and the like generally used to prevent corrosion are mixed. 
     The self-assembled particles  220  may be configured of self-assembled metal particles including at least one material selected from a group configured of magnetic powders or crystalline graphite powders grown to be aligned in one direction by magnetic fields, tin, indium, bismuth, silver, copper and an alloy thereof self-assembled by heating or applying pressure to have high thermal conductivity. The self-assembled metal particles maintain a uniformly dispersed state in the paint as an oxide film is formed on the surface, and as the self-assembled metal particles form protrusions  212  together with the cured paint  211  as they are self-assembled and grown when the paint  211  mixed with the self-assembled particles  220  and the heat sink particles  230  is applied and thermally treated at a temperature of 120° C. to 250° C., the self-assembled metal particles significantly increase the surface area and, at the same time, perform a heat sink function of releasing heat inside the microinverter  10  to the outside by its own thermal conductivity. 
     As fine protrusions are formed on the surface of the cover  200  as the self-assembled particles  220  grow to be adjacent to each other when a magnetic field, heat or pressure is applied, the total surface area of the heat sink paint layer  210  is significantly increased, and heat sink efficiency is improved significantly. 
     In addition, the heat sink particles  230  may include heat sink materials such as phyllite, mordenite, Shungite and the like. The heat sink materials of the above configuration may form blend door heat sink particles  230  by 5 to 15 parts by weight of mordenite and 10 to 20 parts by weight of Shungite with respect to 80 to 120 parts by weight of phyllite. At this point, the heat sink particles  230  may be mixed to have XXX. The phyllite is configured in a grain structure of a plate shape (about 5 μm), contains germanium, selenium and the like, and has excellent thermal conductivity, as well as emitting a large amount of far-infrared radiation, which is radiant energy. The mordenite is a mineral configured in a grain structure of a spherical shape (1 to 3 μm) and having an excellent heat absorption function, and performs a function of releasing radiant energy and a function of heat storage and heat reduction by radiation of far-infrared rays. The Shungite is a mineral configured in a grain structure of a cylindrical shape (about 20 μm), emits far-infrared rays, i.e., radiant energy, by a spherical (ball-shaped) fullerene material bonded with 60 or more carbon atoms existing in the Shungite, and has a characteristic of excellent thermal conductivity. In addition, since the fullerene has a characteristic of shielding electromagnetic waves, the Shungite provides a heat sink function and allows further implementation of a function of shielding electromagnetic waves. In the configuration as described above, as the heat sink particles  230  are formed by arranging in order of connecting the mordenite particles of a spherical shape, Shungite particles of a cylindrical shape, mordenite particles of a spherical shape, and phyllite particles of a plate shape on the phyllite particles of a plate shape, minerals having a variety of particle shapes form a heat release structure. In the structure as described above, the phyllite particles of a plate shape emit far-infrared rays and absorb heat by the heat generated from a heat source, and transfer the heat generated from the heat source to the mordenite particles of a spherical shape by thermal conductivity, and the mordenite particles store the transferred heat (provide an effect of enhancing the efficiency of releasing radiant energy) and transfer the heat to the Shungite particles of a cylindrical shape owing to the characteristics of far-infrared radiation and thermal conductivity, and the Shungite particles transfers the heat to the mordenite particles of a spherical shape positioned above owing to the characteristics of far-infrared radiation and thermal conductivity to store the heat, and at this point, since the structure of hollow fullerene particles having carbon bonds of a ball shape in the Shungite particles having a cylindrical shape transfers energy between the fullerene particles by a resonance phenomenon of resonating on the basis of atomic vibration, it may perform faster energy transfer (heat release). The mordenite particles of a spherical shape stores again the transferred heat energy, and finally transfers the energy to the phyllite particles of a plate shape at the terminal owing to the characteristics of far-infrared radiation and thermal conductivity, and as the phyllite particles of a plate shape secure a large heat sink area again and emit far-infrared rays using the heat sink area, heat is released to the outside through an interface penetration using the permeability property of the far-infrared rays (radiant energy), rather than conventional flow of heat through an interface contact with the air. That is, the surface area is significantly increased by the protrusion structure formed by the self-assembled particles  220  of the heat sink paint layer  210  of the present inventive concept, and as the heat is rapidly released to the outside by the self-assembled particles  220  and the heat sink particles  230  configured inside the paint  211 , the heat inside the microinverter  10  is efficiently released to the outside. 
     In addition, in the present inventive concept, the case lower plate  100  may be configured to include an extended insertion unit  110  extended from the case lower plate  100  toward the outside; and a hinge-coupling unit  120  hinge-coupled to the extended insertion unit  110  to be rotatably installed, so that the extended insertion unit  110  may be insert-coupled between the solar cell panel  20  and one side of the support  30 , and the hinge-coupling unit  120  may be rotated and bolt-coupled on the other side of the support  30 . 
     As described above, the solar cell panel array of the present inventive concept may be configured by integrally mounting the microinverter  10  on each solar cell panel  20  and connecting the solar cell panels  20  in parallel. Accordingly, in the case where the solar cell panels are connected in series as shown in the prior art, the overall output is abruptly lowered when a shade, an error or the like occurs in some solar cell panels. However, in the case of the present inventive concept, as the solar cell panels are connected in parallel, the effect of the shade or broken solar cell panels on the output of the entire solar cell panel array is minimized, and thus degradation of the output is significantly lowered, and therefore, power generation can be stably performed even when a shade or an error occurs in some solar cell panels. 
       FIG.  8    is a front perspective view (a) and a rear perspective view (b) showing a solar cell panel array  1  integrated with a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept,  FIG.  13    is a perspective view showing a microinverter for photovoltaic power generation provided with a heat sink according to an embodiment of the present inventive concept,  FIG.  14    is an exploded perspective view showing a microinverter for photovoltaic power generation provided with a heat sink according to an embodiment of the present inventive concept, and  FIG.  3    is a functional block diagram showing up to the front end of a converter performing MPPT control and DC boosting for AC conversion of the microinverter for photovoltaic power generation provided with a heat sink according to an embodiment of the present inventive concept. 
     As shown in  FIG.  8   , the solar cell panel array  1  integrated with the microinverter includes solar cell panels  20  and microinverters  10  for photovoltaic power generation integrally formed in the solar cell panels, and the solar cell panels  20  may be configured to be connected to each other in parallel as the microinverters  10  are connected to the bus wire  5  in parallel. 
     As described above, as the solar cell panels  20  are connected in parallel through the bus wire  5 , the influence on the power generation efficiency of the entire solar cell panel array  1  is minimized even when specific solar cell panels  20  constituting the solar cell panel array  1  are not irradiated with sunlight due to a shade or the like. Generally, compared with a case where when the solar cell panels  20  are connected in series, the output of the entire solar cell panel array  1  is limited to the power generated by the solar cell panels  20  not irradiated with sunlight due to a shade or the like, or driving of the solar cell panel array  1  is stopped, when the solar cell panels  20  are connected in parallel, the problems that occur when the solar cell panels  20  are connected in series do not occur. 
     In addition, the solar cell panels  20  are configured to include a pair of first and second solar cell modules  410  and  420 , and the microinverter  10  is detachably formed to be integrated with the solar cell panel  20  so that the maximum power point of each of the first and second solar cell modules  410  and  420  may be tracked by adjusting deviation of current of the first and second solar cell modules  410  and  420  with a differential power to convert the power generated by the solar cell panel into AC power and output the AC power. 
     Referring to  FIGS.  13  and  14   , in order to perform tracking of the maximum power point described above, the microinverter  10  for photovoltaic power generation according to an embodiment of the present inventive concept is configured to include a case lower plate  100  formed in a plate shape; a case cover  200  having a heat sink configured of heat sink fins formed on the surface to cover the case lower plate  100 ; and a substrate  300  installed on the case lower plate  100 . 
     Since the case lower plate  100 ; the case cover  200  configured to cover the case lower plate  100 ; and the substrate  300  installed on the case lower plate  100  are the same as those described above, detailed description thereof will be omitted. 
       FIG.  10    is a plan perspective view showing a solar cell panel  20  constituting a solar cell panel array  1  integrated with a microinverter according to an embodiment of the present inventive concept, and  FIG.  15    is a bottom perspective view of the solar cell panel  20  of  FIG.  10   . 
     Referring to  FIGS.  10  and  15   , the solar cell panel  20  integrated with a microinverter for photovoltaic power generation according to the present inventive concept is configured to include a microinverter  10  for photovoltaic power generation, a pair of solar cell modules  410  and  420 , and a support  30  installed on the back side of the solar cell panel  20  to support the solar cell modules  410  and  420 .  FIG.  10    shows the front side of the solar cell panel  20 , and  FIG.  15    shows the back side (bottom side) of the solar cell panel  20 , the microinverter  10 , and the support  30 . 
     That is, in the solar cell panel  20  integrated with a microinverter for photovoltaic power generation according to the present inventive concept, the microinverter  10  for photovoltaic power generation is configured to include a case lower plate  100  formed in a plate shape; a case cover  200  configured to cover the case lower plate  100 ; and a substrate  300  installed on the case lower plate  100 , and as shown in  FIG.  3   , the substrate  300  is configured to include a first conductor  310  connected to a first solar cell module  410  in parallel; a second conductor  320  connected to a second solar cell module  420  in parallel; a first switch  330  connected to the first solar cell module  410  and the first conductor  310  in parallel; a second switch  340  connected to the second solar cell module  420  and the second conductor  320  in parallel; a shuffling inductor  350  connected between the first and second conductors  310  and  320  and the first and second switches  330  and  340 ; a boost inductor  360  connected to the first solar cell module  410 , the first conductor  310 , and the first switch  330 ; a third switch  370  connected to the boost inductor  360  and also connected to the second solar cell module  420 , the second conductor  320 , and the second switch  340 ; a rectifying device  390 ; a DC voltage device  380  such as a DC transformer or the like that boosts DC power to convert into commercial AC power and then outputs the boosted DC power to a DC-AC converter; and an inverter circuit, although not shown in the drawing, for outputting commercial AC power such as 220V-60 Hz or the like by performing DC-AC conversion after receiving the boosted DC power. In addition, at this point, it may be configured to operate the first switch  330 , the second switch  340 , and the third switch  370  by the MPPT controller. 
     The microinverter  10  of the configuration described above may be configured to further include a near field communication unit  253  (see  FIG.  13   ) such as Wi-Fi, Bluetooth or the like, and an AC output port  255 . In the case of  FIGS.  10  and  15   , it is shown that a Wi-Fi communication module having a Wi-Fi antenna is configured as the near field communication unit  253 . According to the configuration of the near field communication unit  253  as described above, the microinverter  10  transmits an identifier for identifying a corresponding solar cell panel  20  and information on a failure or error type to an external control center, a manager computer, an alarm device, or the like when a failure or an error occurs in the solar cell panel  20  due to a shade or the like, so that the solar cell panel  20  in which the failure or error has occurred may be easily identified and handled. In addition, it may be configured to directly connect the solar cell panel to the power system of commercial power by configuring the AC output port  255  as a commercial power plug to be connected to a power socket. 
     Describing with reference to  FIG.  13    again, the case cover  200  has a heat sink  203  configured of heat sink fins  205  on the surface to release the heat generated inside the microinverter to the outside. In addition, a heat sink paint layer  210  for improving the heat sink efficiency by further increasing the surface area of the heat sink  203  may be formed on the surface of the heat sink  203  and the surface of the case lower plate. 
     The heat sink paint layer  210  is configured to include a paint  211 , self-assembled particles  220 , and heat sink particles  230 . 
     Since the paint  211 , the self-assembled particles  220 , and the heat sink particles  230  are the same as those described above, detailed description thereof will be omitted. 
     Hereinafter, a microinverter for photovoltaic power generation according to the present inventive concept will be described in detail with reference to the drawings. 
       FIG.  16    is a perspective view showing a microinverter  10  for photovoltaic power generation according to an embodiment of the present inventive concept,  FIG.  17    is an exploded perspective view showing a microinverter for photovoltaic power generation of  FIG.  16   ,  FIG.  18    is a bottom perspective view showing a fixed panel  100 ′,  FIG.  19    is a bottom perspective view showing a detachable microinverter unit  200 ′, and  FIG.  20    is a partial cross-sectional view showing the microinverter  10  for photovoltaic power generation of  FIG.  16   . 
     As shown in  FIGS.  16  to  20   , the microinverter  10  for photovoltaic power generation (hereinafter, referred to as a ‘microinverter  10 ’) is configured to include a fixed panel  100 ′ attached to the rear surface of the solar cell panel, and a detachable microinverter unit  200 ′ (hereinafter, referred to as a ‘microinverter unit  200 ’) attached to and detached from the fixed panel  100 ′ by screw-coupling. 
     The fixed panel  100 ′ may be configured to include a solar cell wire through hole  140  formed for a solar cell wire  180 , which draws out power of the solar cell panel  20 , to pass through, a plurality of fixing panel nut units  130  formed in an edge area in a cylindrical column shape having a female screw to which a screw S is coupled to fix the fixed panel  100 ′ by screw-coupling, and an inverter terminal socket unit  190  including an inverter terminal socket substrate  191  to which inverter terminal sockets  193  connected to the solar cell wire  180  are attached. 
     As shown in  FIGS.  16  to  18   , the fixed panel  100 ′ is configured to include an extended insertion unit  110  extended from the fixed panel  100 ′ toward the outside; and a hinge-coupling unit  120  hinge-coupled to the extended insertion unit  110  to be rotatably installed, so that the extended insertion unit  110  may be insert-coupled between the solar cell panel  20  and one side of the support  30 , and the hinge-coupling unit  120  may be rotated and bolt-coupled on the other side of the support  30 . After an adhesive  101  for attaching the fixed panel  100 ′ to the rear surface of the solar cell panel  20  is applied to the rear surface of the fixed panel  100 ′ of the configuration described above, the fixed panel  100 ′ may be mounted on the rear surface of the solar cell panel  20  by insert-coupling the extended insertion unit  110  between the solar cell panel  20  and one side of the support  30 , and rotating and bolt-coupling the hinge-coupling unit  120  on the other side of the support  30 . At this point, the adhesive  101  may be a silicone bond or the like. 
     The microinverter unit  200 ′ is configured to include an inverter terminal socket unit through hole  290  having an open top and formed through the bottom surface so that the inverter terminal socket unit  190  of the fixed panel  100 ′ may be inserted inside the microinverter unit  200 ′, an inverter box  220 ′ attached to and detached from the fixed panel  100 ′ by screw-coupling as a plurality of double nut units  230 ′ is formed along the outer edge, a substrate  300  having inverter terminals  293  coupled to the inverter terminal sockets  193 , and mounted inside the inverter box  220 ′, and an inverter box cover  201  that covers the inverter box  220 ′. 
     The double nut unit  230 ′ is configured to include a cover nut unit  231  formed at one side to screw-couple the inverter box cover, and a fixing flange  233  formed to be extended from the lower end of the cover nut unit  231  in the lateral direction to have a through hole  234  formed to communicate with the fixing panel nut unit  130 , and screw-coupled to the fixed panel  100 ′ by a screw S. 
     An LED unit  221  for displaying the driving state of the inverter  10 , a communication antenna  223  for communication, and an AC output port  225  for outputting AC power on which power control is performed after power is generated by sunlight are formed on one side of the inverter box  220 ′. 
     As shown in  FIG.  5   , the substrate  300  is configured to receive power generated by the solar cell panel  20  through the inverter terminals  293  coupled to the inverter terminal sockets  193  of the inverter terminal socket unit  190 , and output AC power through the AC output port  225  by performing power control such as MPPT control, DC-AC conversion, power factor control or the like. In addition, the substrate  300  may include a communication module therein so that the microinverter  10  may transmit driving state information to a management server or the like. 
     The communication antenna  223  and the communication module may be configured to perform near field communication such as Wi-Fi, Bluetooth or the like. As the communication antenna and the communication module are provided, the microinverter  10  transmits an identifier for identifying a corresponding solar cell panel  20  and information on a failure or error type to an external control center, a manager computer, an alarm device, or the like when a failure or an error occurs in the solar cell panel  20  due to a shade or the like, so that the solar cell panel  20  in which the failure or error has occurred may be easily identified and handled. 
       FIG.  3    is a functional block diagram showing up to the front end of a converter performing MPPT control and DC boosting for AC conversion of the microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. 
       FIG.  8    is a front perspective view (a) and a rear perspective view (b) showing a solar cell panel array  1  integrated with a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept, and  FIG.  6    is a rear view showing a solar cell panel integrated with a microinverter for photovoltaic power generation according to an embodiment of the present inventive concept. 
     As shown in  FIGS.  6  and  8   , the solar cell panel array  1  integrated with the microinverter includes solar cell panels  20  and microinverters  10  for photovoltaic power generation integrally formed in the solar cell panels, and as the microinverters  10  are connected to the bus wire  5  in parallel, the solar cell panels  20  may be configured to be connected to each other in parallel. 
     As described above, as the solar cell panels  20  are connected in parallel through the bus wire  5 , the influence on the power generation efficiency of the entire solar cell panel array  1  is minimized even when specific solar cell panels  20  constituting the solar cell panel array  1  are not irradiated with sunlight due to a shade or the like. Generally, compared with a case where when the solar cell panels  20  are connected in series, the output of the entire solar cell panel array  1  is limited to the power generated by the solar cell panels  20  not irradiated with sunlight due to a shade or the like, or driving of the solar cell panel array  1  is stopped, when the solar cell panels  20  are connected in parallel, the problems that occur when the solar cell panels  20  are connected in series do not occur. 
     In addition, the solar cell panels  20  are configured to include a pair of first and second solar cell modules  410  and  420 , and the microinverter  10  is formed to be integrated with the solar cell panel  20  so that the maximum power point of each of the first and second solar cell modules  410  and  420  may be tracked by adjusting deviation of current of the first and second solar cell modules  410  and  420  with a differential power to convert the power generated by the solar cell panel into AC power and output the AC power. 
     Referring to  FIGS.  6  and  8   , the solar cell panel  20  integrated with a microinverter for photovoltaic power generation according to the present inventive concept is configured to include a microinverter  10  for photovoltaic power generation, a pair of solar cell modules  410  and  420 , and a support  30  installed on the back side of the solar cell panel  20  to support the solar cell modules  410  and  420 .  FIG.  8    shows the front side of the solar cell panel  20 , and  FIG.  6    shows the back side (rear side) of the solar cell panel  20 , the microinverter  10 , and the support  30 . 
     When the microinverter  10  of the above configuration is mounted on the rear surface of the solar cell panel  20 , the microinverter  10  is fixed on the rear surface of the solar cell panel  20  of the fixed panel  100 ′ by applying an adhesive on the bottom surface of the fixed panel  100 ′ first, insert-coupling the extended insertion unit  110  between the solar cell panel  20  and one side of the support  30  on the rear surface of the solar cell panel  20 , and rotating and bolt-coupling the hinge-coupling unit  120  on the other side of the support  30 . 
     Thereafter, as the screw S is inserted through the fixing flange  233  of the double nut unit  230 ′ of the inverter box  220 ′ and then screw-coupled to the fixing panel nut unit  130 , the inverter box  220 ′, in which the substrate or the like is mounted, may be detachably mounted on the fixed panel  100 ′. At this point, as the inverter terminals  293  are forcibly insert-coupled to the inverter terminal sockets  193 , the substrate  300  and the solar cell panel  20  electrically communicate each other. 
     Then, the open top of the inverter box  220 ′ is covered with the inverter box cover  201  and tightly sealed by inserting a screw through a cover flange  202  formed to have a through hole in the edge of the inverter box cover  201 , and screw-coupling the screw S to the cover nut unit  231 . 
     As described above, as the present inventive concept may easily attach and detach the detachable microinverter unit  200 ′ including the inverter box  220 ′ and the inverter box cover  201  using screws, repair and replacement may be easily performed, and thus maintenance of the microinverter  10  can be performed remarkably easily. 
     It is obvious that various fastening members such as bolts or screws may be applied as the screw. 
     Describing with reference to  FIG.  16    again, a heat sink paint layer  210  for releasing the heat generated inside the microinverter to the outside may be formed on the outer surfaces of the inverter box cover  201  and the inverter box  220 ′. 
     The heat sink paint layer  210  is configured to include a paint  211 , self-assembled particles  213 , and heat sink particles  215 . 
     Since the paint  211 , the self-assembled particles  220 , and the heat sink particles  230  are the same as those described above, detailed description thereof will be omitted. 
     In addition, as the heat sink paint effectively releases the heat inside the inverter to the outside, there is an effect of remarkably lowering occurrence of a failure of the inverter caused by the heat. 
     Although the technical spirit of the present inventive concept described above has been described in detail in the preferred embodiments, it should be noted that the above-described embodiments are for illustrative purposes and not to limit the present inventive concept. In addition, those skilled in the art may understand that various embodiments are possible within the scope of the technical spirit of the present inventive concept. Therefore, the true technical protection scope of the present inventive concept should be defined by the technical spirit of the appended claims.