This article defines the methods that Tigo uses to perform inverter compatibility tests and discusses the hurdles that Tigo strives to overcome in an ever-expanding market of solar products.
Criteria for Compatibility Testing
Tigo offers extensive inverter testing to confirm compatibility for our TS4 Flex MLPE products. These tests are conducted under an environment where the full operating condition for both products are met.
We focus on these specific criteria for Inverter compatibility:
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Long-term Operation - Duration and performance under varying voltages (High, low, normal).
Testing the dynamic behavior of both the inverter and TS4 system when the DC output of the array is close to the (lower or higher) thresholds of the inverter's input voltage range, as well as the standard operating conditions at maximum power point, to ensure that neither product shows irregular behavior.
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Shade Testing - Inverter reaction to varying shade conditions (static, dynamic, ultra-dynamic).
Test for optimization and nuisance AFCI tripping in multiple shade environments:
• Static - Constant or persistent shading from a fixed structure or obstacle
• Dynamic - Moving shade conditions (clouds, moving obstacles, etc)
• Ultra-Dynamic - Unexpected shading that changes coverage size and location
These varieties of testing behaviors ensure that Tigo's MLPEs and the Inverter behave as expected when experiencing different shade conditions.
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AFCI (If applicable) - Inverter's AFCI responds when there is an arc condition.
Test to ensure that the Inverter's AFCI behaves as designed and that the pairing of Tigo's MLPEs does not contribute to any false tripping. As long as the Inverter's AFCI meets or exceeds the UL-1699B standard for Arc-Fault tripping, the system should not trip under standard conditions. -
Power cycle - Verify inverter turns on when CCA is on and off when CCA shuts off
This is the fundamental trigger for Tigo's RSD solution (as described below), but it is tested as its own parameter to ensure its merit and effectiveness.
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Rapid shutdown - Verifying the rapid shutdown requirements set by the NEC.
Ensuring that all requirements are met for compliance with UL-1741 and that both products operate as expected during RSD conditions.
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Communication - Verify that communications between the CCA & inverter are functioning.
Reviewing all data points displayed by both the Tigo portal (and the inverter's portal) to ensure that the data paths are functioning and the results are correct.
Inverters that meet or exceed our criteria are then added to Tigo's Compatibility List.
Note: Tests are performed with the standard criteria (above). Any tests of products beyond these standards are not necessary to confirm compatibility.
What are the considerations beyond general compatibility?
The Solar Market is vast and ever-expanding. It is difficult for any company to know what new options are being offered by all of the other international manufacturers. Some Inverter manufacturers may offer tools or components, stating that they are fully compatible with generic MLPE usage.
These options may include:
- Built-in Inverter RSD power supply (for data loggers, etc)
- Automatic activation for critical load outputs (during RSD)
- Enhanced AFCI Software/hardware settings
- Shade optimization or MPPT maintenance software
- Data import connections (for capturing MLPE data and displaying it on their portal)
Any options provided by the Inverter manufacturer are not necessarily a part of Tigo's standard compatibility testing and review process. For this reason, you may find that an inverter can be listed as compatible, but their advertised option does not function as expected, when paired with Tigo MLPEs.
IMPORTANT NOTE - The R&D and QA testing process for any optional inverter enhancements are the responsibility of the Inverter's manufacturer. If you find that an option does not appear to be functioning as expected, please reach out to the Inverter Manufacturer to confirm whether it has been specifically designed and/or tested for usage with Tigo Products.