PV Module-Mounted AC Inverter Circuit Integration
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Solution Overview
Problem
Existing photovoltaic inverters have limited reliability and lifetime due to the use of off-the-shelf components, particularly electrolytic capacitors, which restrict their operational lifespan to five to ten years, and fail to achieve economy of scale for rapid solar power adoption.
Innovation Solution
A PV module-mounted AC inverter circuit utilizing integrated circuits, power transistors, solid-dielectric capacitors, inductors, and ancillary components for optimized power conversion and monitoring, with a single-inductor boost converter and delta-sigma modulation for improved efficiency and reliability, reducing component count and enhancing communication capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If off-the-shelf components including electrolytic capacitors are used in photovoltaic inverters, then the inverter can be manufactured with standard components and achieve initial functionality, but the reliability and lifetime are limited to five to ten years
Solution Approach 1:
The patent integrates the inverter circuitry directly into the PV module packaging, merging previously separate components (inverter, PV cells, encapsulant, frame) into a single integrated unit. This integration eliminates the need for separate inverter housing and reduces overall system complexity while improving reliability through direct coupling of components.
Solution Approach 2:
The patent changes the operational parameters by designing the inverter to operate directly at the PV module voltage level without requiring high-voltage DC bus conversion. This parameter change allows the use of solid-state components operating at lower voltages, extending component lifetime from 5-10 years to potentially 25+ years while maintaining manufacturing feasibility.
2Loss of energy
If centralized inverters are used to accumulate DC power from multiple PV modules, then power conversion efficiency is improved through high DC voltage, but the system complexity and single point of failure risk increase
Solution Approach 1:
The patent segments the power conversion function by placing a dedicated inverter circuit within each individual PV module rather than using a centralized inverter for multiple modules. This segmentation creates multiple independent conversion units, eliminating single points of failure and reducing system architecture complexity while maintaining overall conversion efficiency through distributed processing.
Solution Approach 2:
Each PV module with its integrated inverter becomes a self-sufficient unit that independently converts DC to AC without requiring coordination with other modules or a central control system. This self-service approach simplifies system architecture by eliminating the need for complex inter-module communication and centralized control while maintaining efficient power conversion.
3Reliability
If distributed inverters are mounted on each PV module to improve reliability and reduce shading effects, then system robustness is enhanced, but the component count and manufacturing complexity increase
Solution Approach 1:
The patent merges the inverter circuitry with the PV module structure, combining previously separate components (inverter PCB, power electronics, PV cells, encapsulant, frame) into a single integrated assembly. This merging reduces the total component count by eliminating separate inverter housing, mounting hardware, and interconnection components, while maintaining the reliability benefits of distributed power conversion.
Solution Approach 2:
The integrated PV module design creates a universal component that simultaneously performs multiple functions: photovoltaic power generation, DC-AC power conversion, electrical isolation, and structural support. This multi-functionality reduces the need for separate specialized components and simplifies manufacturing by using a standardized module design for both generation and inversion functions.
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 achieves a significant reduction in component count and cost, enhancing reliability and extending the inverter's lifetime to 25 years, while supporting large-scale manufacturing and efficient power conversion with improved power factor and grid synchronization.
Implementation Method 1
An inverter is a device that performs direct current (DC) to alternating current (AC) power conversion... photovoltaic (PV) modules... maximum power is to be extracted
Implementation Method 2
The inverter circuit includes a single-inductor boost converter and delta-sigma modulation for improved efficiency... direct current to alternating current power conversion
Data Source
AI summary
A photovoltaic module-mounted AC inverter circuit uses one or more integrated circuits, several power transistors configured as switches, several solid-dielectric capacitors for filtering and energy storage, several inductors for power conversion and ancillary components to support the above elements in operation. The integrated circuit includes all monitoring, control and communications circuitry needed to operate the inverter. The integrated circuit controls the activity of pulse-width modulated power handling transistors in both an input boost converter and a single-phase or multi-phase output buck converter. The integrated circuit also monitors all power processing voltages and currents of the inverter and can take appropriate action to limit power dissipation in the inverter, maximize the available power from the associated PV module and shut down the inverter output if the grid conditions so warrant. The integrated circuit implements power line communications by monitoring the AC wiring for signals and generating communications signals via the same pulse-width modulation system used to generate the AC power. Communications is used to report inverter and PV module status information, local identification code and to allow for remote control of inverter operation.