The best technologies to combat shading in solar panels focus on minimizing the performance losses caused by partial or full shading on cells or modules. These technologies allow solar panels to operate independently or bypass shaded sections to maintain power output. Here are the key solutions:
1. Bypass Diodes
- Most solar panels incorporate bypass diodes to provide an alternate pathway for current when sections of a panel become shaded or faulty.
- These diodes prevent overheating and power loss by allowing current to bypass shaded cell groups within the module.
- Typically, panels have three bypass diodes dividing the panel into groups, minimizing the effect of shading from affecting the entire panel but only a fraction (one-third or less) of it.
2. Half-Cut Cell Technology
- Half-cut solar panels split each solar cell in half, arranging them in two groups functioning in parallel.
- This reduces current and internal resistance, lowers operating temperature, and improves shade tolerance because shading one part does not affect the other half as strongly.
- They effectively reduce power loss due to shading from one-third (traditional panels) to about one-sixth per shaded section.
- Half-cut panels are highly efficient and durable but come with a somewhat higher initial cost.
3. Module-Level Power Electronics (MLPE)
MLPE includes:
- Microinverters: Installed on each panel, microinverters convert DC to AC at the panel level, allowing every panel to operate independently. This prevents shading on one panel from dragging down the entire string’s output and enables panel-level monitoring and optimization.
- Power Optimizers: These DC-DC converters optimize power output of individual panels by adjusting voltage and current, ensuring shaded panels do not reduce the performance of unshaded panels.
- Both MLPE technologies maximize energy harvest in shaded conditions and improve system reliability.
- Microinverters have the advantage of eliminating single points of failure and simplifying system expansion, albeit at a higher initial cost than power optimizers.
4. Stringing Arrangements and Multi-MPPT Inverters
- Designing systems with panels that experience shading placed in separate strings or using inverters with multiple Maximum Power Point Trackers (MPPTs) can reduce shading impacts.
- Multi-MPPT inverters allow different panel strings to operate independently, reducing losses when only some strings are shaded.
- While effective, these approaches are less powerful than MLPE solutions for complex shading scenarios.
5. Emerging and Complementary Technologies
- Bifacial panels capture light from both sides, potentially compensating for some shading effects.
- Future technologies under research include perovskite solar cells, which may be less sensitive to shading and exhibit better performance in low-light conditions, and advanced power electronics with AI-driven optimization to predict and adapt to shading patterns.
Summary Table
| Technology | Description | Benefits | Drawbacks |
|---|---|---|---|
| Bypass Diodes | Internal diodes bypass shaded cell groups | Prevents hotspot damage, partial shading mitigation | Limited to groups of cells |
| Half-Cut Cells | Cells cut in half, arranged in parallel groups | Reduces shading impact, lowers resistance and heat | Higher cost, possible internal defects |
| Microinverters | Inverter per panel | Independent operation, panel-level monitoring | Higher upfront cost |
| Power Optimizers | DC-DC converters per panel | Optimizes output, less shading impact | Additional hardware cost |
| Multi-MPPT Inverters | Inverters with multiple MPPT inputs | Better performance for uneven shading | Less effective than MLPE |
| Bifacial Panels | Capture light from front and back | Potential shading compensation | Installation-dependent benefits |
| Emerging Tech (Perovskite, AI optimization) | New materials and smarter electronics | Potential for superior shading tolerance | Still in development |
In conclusion, the best practical technologies today to combat shading are microinverters and power optimizers (MLPEs) combined with half-cut cell panels and bypass diodes embedded within modules. These solutions allow panels to perform closer to their maximum capacity even when partially shaded and greatly mitigate the power losses caused by complex shading patterns.
Original article by NenPower, If reposted, please credit the source: https://nenpower.com/blog/what-are-the-best-technologies-to-combat-shading-in-solar-panels/
