CABLE INTEGRATED SOLAR INVERTER
Systems for converting a standard direct current (DC) power from solar panels into a rectified DC power signal for further conversion into alternating current (AC) power are described herein. In some example embodiments, the systems may include distributed power converters and a grid interface unit connected by a trunk cable. In some example embodiments, the power converters may be embedded in the trunk cable.
1 . A method of converting direct current (DC) power from a plurality of photovoltaic modules into alternating current (AC) power, the method comprising:
receiving one or more DC power signal at a plurality of photovoltaic modules;
converting, via a plurality of distributed power converters, the one or more DC power signal into a rectified sine wave signal, wherein each of the distributed power converters comprises a buck converter; and
converting, via a grid interface unit, the rectified sine wave signal to an AC signal for supply to the power grid, the grid interface unit being electrically connected to the power converters and to a power grid;
wherein each photovoltaic module of the plurality of photovoltaic modules is configured for being electrically connected to a respective distributed power converter of the plurality of distributed power converters, and wherein the photovoltaic modules of the plurality of photovoltaic modules are not connected to one another in series.
2 . The method of claim 1 , the plurality of photovoltaic modules is configured for being connected in series; and wherein each of the distributed power converters is configured for being electrically connected to a respective photovoltaic module of the plurality of photovoltaic modules.
3 . The method of claim 1 , wherein the grid interface unit comprises an unfolding bridge for conversion from the rectified signal to the AC signal for supply to the power grid.
4 . The method of claim 3 , wherein converting the rectified sine wave signal to the AC signal comprises reversing polarity of the rectified sine wave signal on alternate pulses to an AC compatible signal, wherein the unfolding bridge comprises circuitry is configured to function as an H-bridge.
5 . The method of claim 1 , wherein the rectified sine wave signal comprises a half-sine wave.
6 . The method of claim 5 , wherein the half-sine wave comprises a half-wave of one of at least a sinusoidal wave including a sine wave, a cosine wave, a shifted sine wave, or a shifted cosine wave.
7 . The method of claim 1 , further comprising producing, via each of the plurality of power converters, a half-sine wave signal.
8 . The method of claim 7 , further comprising:
producing each respective half-sine wave signal by synchronizing the power converters with each of the plurality of power converters and the grid interface unit; and
adding each of the respective half-sine wave signals in the grid interface unit to form the rectified sine wave signal of a combined output voltage from the plurality of power converters.
9 . The method of claim 1 , further comprising:
synchronizing, via the grid interface unit, the power converters; and
communicating with the power converters through a combined synchronization and communication line in a trunk cable.
10 . The method of claim 1 , wherein the power converters are each configured to produce an individual part of a rectified sine wave signal, such that when combined the individual parts form a full rectified sine wave signal.
11 . The method of claim 1 , further comprising synchronizing the power converters by a combined synchronization and communication signal produced by the grid interface unit, wherein the combined signal includes communication bits.
12 . The method of claim 1 , wherein the grid interface unit comprises a fault detection system, a monitoring system, a synchronization system, and a communication system.
13 . The method of claim 1 , further comprising preventing electrical signals from propagating towards the plurality of power converters and the connected photovoltaic modules via a blocking diode connected in series with the plurality of power converters.
14 . The method of claim 1 , wherein the power converters and the grid interface unit are connected by a trunk cable.
15 . The method of claim 14 , wherein the power converters are embedded in the trunk cable.
16 . The method of claim 14 , wherein each of the plurality of power converter comprises a weather proof cartridge and a housing attached to the trunk cable, the weather proof cartridge configured for removable insertion into the housing.
17 . The method of claim 16 , wherein each power converter housing is embedded in the trunk cable.
18 . The method of claim 14 , further comprising weatherproof housing for housing one or more of the plurality of power converters.
19 . The method of claim 14 , wherein the grid interface unit is located remotely from the plurality of power converters.