Photovoltaic Module Interleaved Converter Junction Box
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Solution Overview
Problem
Existing photovoltaic modules face challenges in stably outputting alternating current (AC) voltage, particularly in reducing the size of the junction box while maintaining high-power AC voltage output, which affects the thickness and efficiency of the module.
Innovation Solution
A photovoltaic module with a power conversion module that includes at least three interleaving converters, a capacitor, and an inverter unit, where the controller adjusts switching periods and phase differences to operate in critical conduction mode, allowing for reduced circuit device size and increased efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional power conversion circuits are used, then the junction box can convert DC to AC, but the junction box thickness increases and power conversion efficiency decreases
Solution Approach 1:
The power conversion module is divided into multiple interleaved converter circuits (first converter circuit, second converter circuit, third converter circuit) that operate in parallel. Each converter circuit processes a portion of the power conversion task independently, allowing the system to achieve high power conversion efficiency while maintaining a compact junction box structure through distributed processing.
Solution Approach 2:
The interleaved converter circuits operate with different switching frequencies and phase shifts. By periodically switching the power conversion operations across multiple circuits with staggered timing, the system reduces current ripple and thermal stress, thereby improving overall power conversion efficiency without requiring larger components that would increase junction box thickness.
2Length of stationary object
If the junction box size is reduced, then the module thickness decreases, but the ability to maintain high-power AC voltage output is compromised
Solution Approach 1:
The power conversion functionality is segmented into multiple interleaved converter circuits that share the total power conversion load. This allows the system to maintain high AC voltage output power capability while using smaller individual converter components, thus reducing the overall junction box thickness without sacrificing power output capability.
Solution Approach 2:
Multiple converter circuits are merged into a single integrated power conversion module within the junction box. By combining the functions of multiple converters that operate in parallel with interleaved switching, the system achieves high-power AC voltage output from a compact integrated structure, maintaining power capability while reducing junction box thickness.
3Productivity
If switching frequency is increased to improve response speed, then power conversion efficiency improves, but switching losses increase
Solution Approach 1:
The total switching burden is segmented across multiple interleaved converter circuits operating at different phases. Each converter operates at a manageable switching frequency, distributing the switching losses across multiple components rather than concentrating them in a single high-frequency switch, thereby improving response speed while controlling overall switching losses.
Solution Approach 2:
The converter circuits employ periodic switching with optimized duty cycles and phase shifts. By using periodic switching actions with appropriate timing, the system achieves fast power conversion response while allowing sufficient time for energy recovery and minimizing peak switching losses through controlled periodic operation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution enables stable AC voltage output with reduced junction box thickness and improved power conversion efficiency, preventing power output reduction and current distortion.
Implementation Method 1
a solar cell that directly converts photovoltaic energy into electrical energy using a semiconductor device
Implementation Method 2
a power conversion module to convert direct current voltage supplied from the solar cell module into alternating current voltage
Data Source
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AI summary
A photovoltaic module is discussed. The photovoltaic module includes a solar cell module including a plurality of solar cells and a junction box attached to a rear surface of the solar cell module, the junction box including a power conversion module to convert direct current (DC) voltage supplied from the solar cell module into alternating current (AC) voltage and to output the AC voltage, wherein the power conversion module included at least one bypass diode to receive the DC voltage from the solar cell module, a converter unit to power-convert the DC voltage from the at least one bypass diode, the converter unit including at least three interleaving converters, a capacitor to store voltage output from the converter unit, and an inverter unit to output the AC voltage using the voltage stored in the capacitor. Consequently, it is possible to stably output AC voltage.