Photovoltaic Device

Abstract

The invention relates to a tandem PV cell group (1) having two PV cells (11, 21) of different cell types. A separate power electronic unit (31, 32) is assigned to each of the PV cells in such a manner that a voltage generated in the particular PV cell or the corresponding power yield can be supplied to the assigned power electronic unit. The power electronic units can be operated independently of one another with the aid of a control device (40) in such a manner that each PV subsystem having one of the PV cells in each case and the power electronic unit assigned to the particular PV cell operates at the optimum operating point thereof. For this purpose, the control device can operate in such a manner that, during operation of the power electronic unit of each PV subsystem, a product of the power yield and the cell voltage of the PV cell assigned to the particular power electronic unit is at a maximum.

1 . A photovoltaic (PV) device comprising:
 a multi-PV cell group including at least one first PV cell of a first cell type and one second PV cell of a second cell type, wherein the first cell type and the second cell type differ from one another, and wherein each PV cell of the one first PV cell and the one second PV cell is configured to provide an electric cell voltage under light incidence on the respective PV cell;   power electronics including a separate first power electronics unit that is assigned to the one first PV cell and a separate second power electronics unit that is assigned to the one second PV cell, wherein the electric cell voltage generated in the respective PV cell and a corresponding current yield are feedable to a separate power electronics unit of the separate first power electronics unit and the separate second power electronics unit assigned to the respective PV cell; and   a controller configured to control the power electronics,   wherein the separate first power electronics unit and the separate second power electronics unit are operable independently of one another via the controller, such that each PV subsystem, each of which includes the one first PV cell or the one second PV cell and the power electronics unit assigned to the respective PV cell, operates at a respective optimum operating point.   
     
     
         2 . The PV device of  claim 1 , wherein the controller is further configured to control, during operation of the the respective separate power electronics unit, such that a product of the current yield and the cell voltage of the respective PV cell assigned to the respective separate power electronics unit is at a maximum. 
     
     
         3 . The PV device of  claim 2 , wherein the controller is further configured to adjust, during the control of the respective separate power electronics unit, an input resistance of the respective power electronics unit, such that a product of the current yield and the cell voltage of the respective PV cell assigned to the respective power electronics unit is at a maximum. 
     
     
         4 . The PV device of  claim 1 , further comprising a sensor device, the sensor device comprising:
 a first sensor configured to determine temperatures of the one first PV cell and the one second PV cell, determine an ambient temperature of the multi-PV cell group, or a combination thereof, wherein one or more parameters describing the temperatures, the ambient temperature, or the temperatures and the ambient temperature are fed to the controller as a first input variable, a second input variable, or the first input variable and the second input variable, respectively;   a second sensor configured to determine a light intensity incident on the PV device, wherein a parameter describing the light intensity is fed to the controller as a third input variable;   a sensor configured to determine a spectrum of a light incident on the PV device, wherein a parameter describing the spectrum is fed to the controller as a fourth input variable; or   any combination thereof,   wherein the controller is further configured to control the separate first power electronics unit and the separate second power electronics unit based on the first input variable, the second input variable, the third input variable, the fourth input variable or any combination thereof fed thereto.   
     
     
         5 . The PV device of  claim 4 , wherein the controller is further configured to perform the control, such that, depending on the first input variable, the second input variable, the third input variable, the fourth input variable, or the respective combination thereof for each power electronics unit of the separate first power electronics unit and the separate second power electronics unit, an input resistance is determined and set such that a product of the current yield and the cell voltage of the PV cell assigned to the respective power electronics unit is at a maximum. 
     
     
         6 . The PV device of  claim 1 , wherein the first cell type and the second cell type are selected such that a PCE maxima of the first cell type and a PCE maxima of the second cell type lie in different spectral ranges. 
     
     
         7 . The PV device of  claim 1 , wherein the one first PV cell is a perovskite-based PV cell, the one second PV cell is a silicon-based PV cell, or a combination thereof. 
     
     
         8 . The PV device of  claim 7 , wherein the controller is further configured to control the respective power electronics unit assigned to the perovskite-based PV cell such that hysteresis of output variables of the first PV cell is compensated. 
     
     
         9 . The PV device of  claim 1 , wherein the controller is further configured to execute the control of the separate first power electronics unit and the separate second power electronics unit such that aging of a respective PV cell, soiling of the multi-PV cell group, or a combination thereof is compensated. 
     
     
         10 . A method for operating a photovoltaic (PV) device, the PV device including a multi-PV cell group, the multi-PV cell group including at least one first PV cell of a first cell type and one second PV cell of a second cell type, wherein the first cell type and the second cell type differ from one another, and wherein each PV cell of the one first PV cell and the one second PV cell provides an electric cell voltage under light incidence on the respective PV cell, the PV device further including power electronics, the power electronics including a separate first power electronics unit that is assigned to the one first PV cell and a separate second power electronics unit that is assigned to the one second PV cell, wherein an electric cell voltage generated in the respective PV cell and a corresponding current yield are fed to a separate power electronics unit of the separate first power electronics unit and the separate second power electronics unit assigned to the respective PV cell, the PV device further including a controller for controlling the power electronics, the method comprising:
 operating, by the controller, the separate first power electronics unit and the separate second power electronics unit independently of one another, such that each PV subsystem, each of which has a respective PV cell of the one first PV cell and the one second PV cell and the separate power electronics unit assigned to the respective PV cell, operates at an optimum operating point of the receptive PV subsystem.   
     
     
         11 . The method of  claim 10 , wherein during the operating of the separate power electronics unit of each PV subsystem, the respective separate power electronics unit is controlled, such that a product of a current yield and a cell voltage of the PV cell assigned to the respective separate power electronics unit is at a maximum. 
     
     
         12 . The method of  claim 11 , further comprising:
 controlling the respective separate power electronics unit; and   adjusting an input resistance of the respective separate power electronics unit during the controlling of the respective separate power electronics unit, such that the product of the current yield and the cell voltage of the PV cell assigned to the respective separate power electronics unit is at a maximum.   
     
     
         13 . The method of  claim 10 , wherein the PV device further comprising a sensor device, the method further comprising:
 determining, by the sensor device, temperatures of the one first PV cell, the one second PV cell, or the one first PV cell and the one second PV cell, determining, by the sensor device, an ambient temperature of the multi-PV cell group, or determining, by the sensor device, the temperatures of the one first PV cell, the one second PV cell, or the one first PV cell and the one second PV cell and determining, by the sensor device, the ambient temperature of the multi-PV cell group, wherein one or more parameters describing the temperatures, the ambient temperature, or the temperatures and the ambient temperature are fed to the controller as a first input variable, a second input variable, or the first input variable and the second input variable, respectively;   determining, by the sensor device, a light intensity incident on the PV device, wherein a parameter describing the light intensity is fed to the controller as a third input variable; and   determining a spectrum of a light incident on the PV device, wherein a parameter describing the spectrum is fed to the controller as a fourth input variable; or   any combination thereof,   wherein the separate first power electronics unit and the separate second power electronics unit are controlled based on the first input variable, the second input variable, the third input variable, the fourth input variable, or any combination thereof fed to the controller.   
     
     
         14 . The method of  claim 13 , wherein the control is executed, such that, depending on the first variable, the second variable, the third variable, the fourth variable, or the respective combination thereof, for each power electronics unit of the separate first power electronics unit and the separate second power electronics unit, that input resistance is determined and set such that the product of the current yield and the cell voltage of the PV cell assigned to the respective power electronics unit is at a maximum. 
     
     
         15 . The method of  claim 10 , wherein the separate first power electronics unit and the separate second power electronics unit are controlled such that influences caused by aging of a respective PV cell, influences caused by soiling of the multi-PV cell group, or the influences caused by aging of the respective PV cell and the influences caused by soiling of the multi-PV cell group are compensated. 
     
     
         16 . The PV device of  claim 5 , wherein the controller is configured to perform the control based on lookup tables or in a model-based manner. 
     
     
         17 . The method of  claim 14 , wherein the control is executed based on lookup tables or in a model-based manner.