Today's photovoltaic power systems are generally comprised of a single photovoltaic module or multiple modules connected by combinations of series and parallel circuits as a photovoltaic array. In the case of a single-module system producing alternating current (AC) power output, the photovoltaic module is connected to the inverter or load through a junction box (J-box) that incorporates a fuse to protect the photovoltaic module if backfeeding from other sources (e g; a power utility or a battery) is possible. The photovoltaic modules used in these systems are configured either with or without a frame. Frameless photovoltaic modules are generally referred to as a laminate. For conventional systems that utilize multiple laminates or modules, the laminates or modules are interconnected via junction boxes or flying leads and external wiring that must be rated sunlight-resistant and sized to carry the rated currents. Some conventional photovoltaic system installations require that the direct current (DC) and AC wiring be installed in properly sized and anchored conduit.
A typical method of interconnecting the DC circuits in a conventional photovoltaic system is to have a J-box at the top of each photovoltaic module that provides the terminal block to connect the module circuit to flying-lead conductors that are then fitted with a connector. The J-box also houses the series or “blocking” diode often required by codes and standards to protect the module, especially if more than two strings of modules are paralleled at the combiner box or at the inverter. The module is often constructed with a bypass diode(s) that is(are) usually required for conventional photovoltaic applications. This arrangement is used to connect modules in series. Modules are connected in series until the summed operating voltage is within the optimum DC voltage window of the central or string inverter. The connections are typically made under the modules by plugging connectors together or at distributed J-boxes. Some installations leave insufficient space to allow the installer to make the connections reliably. The central inverter can generally handle multiple strings of photovoltaic modules that are then wired in parallel in a string-combiner assembly or box before DC power is fed to the inverter.
The AC Photovoltaic (PV) Building Block provides a fully integrated and self-containing AC PV Building Block device and method that allows photovoltaic applications to become true plug-and-play devices. The AC PV Building Block eliminates all DC wiring, the requirement for the fuse, the need for bypass diodes or series diodes, the J-box, and connections. All connections except the final AC connections are part of the integrated package of the invention.
The AC PV Building Block combines, contains, and integrates almost all of the electrical and mechanical elements of a PV system while eliminating the traditional DC voltage concerns of today's PV systems. The building block consists of an innovative module and method by which AC PV power is generated in the form of DC. Furthermore, the DC will be converted to AC, and power will be exported through one or more power conversion and transfer units attached to the module. The Building Block can be used as a PV power source that has only AC power out, and can be used alone or in an array.
The AC PV Building Block can be employed with any size and/or shape of photovoltaic system that provides AC power to: 1) the utility grid, 2) mini-grids utilizing other sources of AC electrical generation often referred to as hybrid systems, or 3) standalone power systems that typically use electrical energy storage and an inverter to supply AC power to off-grid loads such as remote residences, communications stations, emergency lighting, and the multitude of remote energy systems requiring AC power.
Additionally, the invention can be combined to form complete photovoltaic energy systems that use a single or multiple photovoltaic modules where the entire power interconnection, conversion, protection, and combining can take place within a listed or certified structure that also is used to mount, attach, and join photovoltaic modules.