Solar-battery integrated DC system
| DWPI Title: Solar-battery integrated direct current system for controlling current flow on direct current bus regardless of type of inverter and implementing photovoltaic system in parallel with battery system, has inverter that controls alternating current to inverter output terminals |
| Abstract: A DC bus is connected to a PV array, a battery or both, to power a grid connected inverter load on the bus. A system and method is described for controlling current flow on a DC bus regardless of the type of inverter. A converter receives a DC battery voltage. A switching module controls current flow through the converter. A current generator generates a reference current in response to a reference voltage. A comparator connected at the output of the current generator compares the reference current with a battery current and outputs a signal to a controller. The controller generates a reference value. A PWM generator modulates the switch module to control current flow and energy flow between the DC bus and the battery. The current from the DC bus to the inverter is controlled to allow proper grid-connected operation regardless of inverter type. |
| Use: Solar-battery integrated direct current system for controlling current flow on direct current bus regardless of type of inverter and implementing solar photovoltaic system in parallel with a battery system. |
| Advantage: The system implements a solar photovoltaic plus battery energy source that can be tied to a grid using commercially available phototransistor inverters or micro-inverters with arbitrary resource management characteristics including peak power tracking and droop so that the system benefits electrical power consumers through cost savings as well as smaller footprint and simpler grid connection, and thus providing a complete energy storage combination package at a lower cost, and/or as a unit to connect a battery to a grid using commercial off-the-shelf (COTS) inverters intended for solar PV system, or to connect distributed resource using COTS inverters. The system allows the battery, standby power system, and DC/DC converter system to be connected to any inverter. |
| Novelty: The system (102) has a controller (100) that comprises a pair of input terminals (34) for receiving direct current (DC) battery voltage from a battery (30). A switching module controls a bidirectional current flow between the battery and a DC bus. A control path controls the switching module. A comparator is connected at an output of a current generator. A controller module is configured to generate a reference value. A pulse width modulating generator is configured to receive a reference value and modulate the switching module to control the current flow and an energy flow between the DC bus and the battery. The DC bus is connected to a photovoltaic (PV) array (10) and an inverter. The inverter controls alternating current (AC) to inverter output terminals (20). The controller module is a proportional-integral controller. A commercial off-the-shelf (COTS) multi-input inverter is selected from a group consisting of maximum power point tracking and DROOP. |
| Filed: 10/13/2021 |
| Application Number: US17500632A |
| Tech ID: SD 15501.1 |
| This invention was made with Government support under Contract No. DE-NA0003525 awarded by the United States Department of Energy/National Nuclear Security Administration. The Government has certain rights in the invention. |
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