Multi-Input Converter IV Curve Scanning Under Low PV Voltage
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Solution Overview
Problem
Conventional IV curve scanning at the module level for multi-input converters is affected by low PV input voltage, leading to premature termination and incomplete IV curve scanning.
Innovation Solution
An IV curve scanning method and device that determine a starting scanning voltage, starting scanning moment, and scanning voltages at target points for each input converter based on a preset starting voltage, minimum voltage, and number of target scanning points, ensuring at least one input converter's scanning voltage exceeds the target voltage at each point, using an auxiliary power supply and controller to perform the scanning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If IV curve scanning is performed at module level with multi-input converter, then measurement precision is improved, but the scanning is affected by low PV input voltage causing premature termination
Solution Approach 1:
The patent introduces an auxiliary power supply as an intermediary component to provide supplemental voltage to the multi-input converter during IV curve scanning. This mediator ensures that the converter receives sufficient voltage even when PV input voltage is low, preventing premature termination and ensuring complete scanning across all operating conditions.
Solution Approach 2:
The patent dynamically adjusts the operating parameters of the multi-input converter by controlling the duty cycle and switching frequency based on the detected PV input voltage level. When voltage drops below a threshold, the system modifies these parameters to maintain stable operation and complete the scanning process, thereby resolving the contradiction between measurement precision and scanning stability.
2Power
If PV input voltage is too low, then the voltage supplied to multi-input converter is insufficient, but increasing voltage would require additional power supply components
Solution Approach 1:
The auxiliary power supply is designed with multi-functionality: it serves both as a voltage supplement during low-PV conditions and as a standard power source during normal operation. This universal component handles multiple scenarios without requiring separate dedicated circuits, thereby maintaining power supply sufficiency while avoiding excessive device complexity.
Solution Approach 2:
The patent merges the auxiliary power supply function with the existing multi-input converter structure by integrating voltage regulation and control logic into the same control unit. This consolidation approach ensures sufficient voltage supply during low-PV conditions while avoiding the need for separate complex power supply systems, thus balancing power adequacy with structural simplicity.
3Measurement precision
If IV curve scanning is performed sequentially for each input converter, then measurement precision is maintained, but scanning time increases
Solution Approach 1:
The patent implements periodic scanning action where the multi-input converter cycles through each input converter in a predetermined sequence rather than performing continuous sequential scanning. This periodic approach maintains measurement precision by systematically visiting each converter while reducing total scanning time through efficient time-multiplexed operation and parallel data acquisition capabilities.
Data Source
AI summary
An IV curve scanning method and an IV curve scanning device for a multi-input converter are provided. For each of input converters in the multi-input converter, a starting scanning voltage, a starting scanning moment, and scanning voltages at respective target scanning points are so determined based on a preset starting voltage, a minimum voltage and a preset number of the target scanning points that at each of the target scanning points there is at least one of the input converters whose scanning voltage is greater than a target voltage. The IV curve scanning for the input converter is performed based on the starting scanning voltage, the starting scanning moment, and the scanning voltages at respective target scanning points.