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 solar inverter system for converting direct current (DC) power from a plurality of photovoltaic modules into alternating current (AC) power, the solar inverter system comprising:
a plurality of photovoltaic modules;
a plurality of distributed power converters configured for being connected in series, wherein each of the distributed power converters is configured for being electrically connected to a respective photovoltaic module of the plurality of photovoltaic modules, and wherein each of the distributed power converters comprises a buck converter configured for converting a DC power signal received from the a respective photovoltaic module into a rectified sine wave signal; and
a grid interface unit configured to be electrically connected to the power converters and to a power grid, wherein the grid interface unit is configured to convert the rectified sine wave signal produced by the plurality of converters to an AC signal for supply to the 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 solar inverter system 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.
3. The solar inverter system of claim 2 , wherein the unfolding bridge comprises circuitry configured to function as an H-bridge to reverse polarity of the rectified sine wave signal on alternate pulses to an AC compatible signal.
4. The solar inverter system of claim 1 , wherein the rectified sine wave signal comprises a half-sine wave.
5. The solar inverter system of claim 4 , 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.
6. The solar inverter system of claim 1 , wherein each of the one or more power converters each produces a half-sine wave signal.
7. The solar inverter system of claim 6 , wherein the power converters are synchronized with each of the plurality of power converters and the grid interface unit to produce each respective half-sine wave signal and configured such that their respective half-sine wave signals are added in the grid interface unit to form the rectified sine wave signal of a combined output voltage from the plurality of power converters.
8. The solar inverter system of claim 1 , wherein the grid interface unit is configured to synchronize the power converters and communicate with the power converters through a combined synchronization and communication line in the trunk cable.
9. The solar inverter system 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.
10. The solar inverter system of claim 1 , wherein the power converters are synchronized by a combined synchronization and communication signal produced by the grid interface unit, wherein the combined signal includes communication bits.
11. The solar inverter system of claim 1 , wherein the grid interface unit further comprises a fault detection system, a monitoring system, a synchronization system, and a communication system.
12. The solar inverter system of claim 1 , further comprising a blocking diode connected in series with the plurality of power converters, such that electrical signals are prevented from propagating towards the plurality of power converters and the connected photovoltaic modules.
13. The solar inverter system of claim 1 , wherein the power converters and the grid interface unit are connected by a trunk cable.
14. The solar inverter system of claim 13 , wherein the power converters are embedded in the trunk cable.
15. The solar inverter system of claim 13 , 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.
16. The solar inverter system of claim 15 , wherein each power converter housing is embedded in the trunk cable.
17. The solar inverter system of claim 13 , further comprising weatherproof housing for housing one or more of the plurality of power converters.
18. The solar inverter system of claim 13 , wherein the grid interface unit is located remotely from the plurality of power converters.