Systems and Methods to Balance Solar Panels in a Multi-panel System

Abstract

Systems and methods to balance currents among a plurality of photovoltaic units connected in series. In aspect, a management unit is coupled between a photovoltaic energy production unit and a string of energy production units. The management unit has an energy storage element (e.g., a capacitor) connected to the photovoltaic energy production unit. The management unit further has a switch to selectively couple to the energy storage element and the photovoltaic energy production unit to the string. The management unit allows the current in the string to be larger than the current in the photovoltaic energy production unit.

What is claimed is: 
     
         1 . A management unit in a photovoltaic energy production system, comprising:
 a circuit to periodically connect and disconnect a solar module to and from a power bus according to a duty cycle, the duty cycle being adjustable to operate the solar module at a maximum power point; and   a controller to receive operating parameters from first management units coupled to the power bus, each of the first management units to determine operating parameters of a respective solar module and transmit the operating parameters of the respective solar module to the controller, the controller to determine duty cycles for the first management units based at least in part on the operating parameters received from the first management units.   
     
     
         2 . The management unit of  claim 1 , wherein the power bus is a serial power bus. 
     
     
         3 . The management unit of  claim 2 , wherein each of the first management units has a switch to periodically connect and disconnect a respective solar module to and from the power bus. 
     
     
         4 . The management unit of  claim 3 , wherein the controller is configured to determine different phases for respective switches in the first management units. 
     
     
         5 . The management unit of  claim 2 , wherein the operating parameters include at least one of: current, voltage, and temperature. 
     
     
         6 . The management unit of  claim 5 , wherein the controller is configured to calculate estimated maximum power points of solar modules connected on the serial power bus, wherein the duty cycles are determined based on the estimated maximum power points of the solar modules. 
     
     
         7 . The management unit of  claim 1 , wherein the management unit has only one output to supply electricity generated by the solar module coupled to the circuit. 
     
     
         8 . The management unit of  claim 1 , wherein the management unit is connected in series with the first management units of solar modules on the serial power bus.