Inverter Burst Mode for Solar MPP Tracking
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Solution Overview
Problem
Solar panels face inefficiencies in power conversion due to nonlinear relationships between current and voltage, leading to suboptimal performance during changes in solar irradiance and temperature, particularly at low irradiance levels, where conventional methods struggle to efficiently track the maximum power point (MPP) and maintain optimal operation.
Innovation Solution
The apparatus employs a burst mode operation in inverters, storing energy during storage periods and releasing it in bursts to converge towards the MPP, using feedback loops and power measurements to adjust operating parameters, ensuring the inverter operates proximate to the MPP, thereby improving efficiency and rapid convergence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional continuous operation mode is used during low irradiance, then the inverter can continuously convert power, but the system efficiency deteriorates due to inability to track MPP effectively
Solution Approach 1:
The patent implements burst mode operation where the inverter alternates between active power conversion periods and idle periods. During low irradiance conditions, the inverter performs brief burst conversions followed by idle periods, allowing the PV module to return to MPP between bursts. This periodic operation resolves the contradiction by maintaining some power conversion capability while preventing continuous inefficient operation that would lose energy.
Solution Approach 2:
The patent uses preliminary action by performing maximum power point tracking adjustments during idle periods before the next burst conversion. The system proactively re-establishes MPP conditions during non-conversion periods, ensuring that when the next burst occurs, the PV module is optimally positioned for efficient power extraction, thus preventing energy loss during the conversion process.
2Reliability
If MPPT tracking is performed continuously, then the MPP can be maintained, but the response time to irradiance changes increases due to measurement and adjustment delays
Solution Approach 1:
The patent applies periodic action by performing MPP measurements and adjustments only during idle periods between burst conversions, rather than continuously. This allows the system to quickly detect irradiance changes and re-establish MPP during the idle time, significantly improving response speed while maintaining tracking accuracy through focused measurement efforts during relevant periods.
Solution Approach 2:
The system uses self-service by leveraging the natural idle periods that occur during burst mode operation to perform self-adjustment and MPP tracking. Rather than requiring dedicated continuous tracking resources, the inverter uses its own operational pauses to automatically recalibrate and maintain optimal performance, improving response speed without sacrificing reliability.
3Productivity
If the inverter operates at low power during low irradiance, then it can continue generating electricity, but the conversion efficiency deteriorates significantly
Solution Approach 1:
The patent resolves this contradiction by implementing burst mode where the inverter operates at high power during brief active periods followed by idle periods during low irradiance conditions. This periodic operation allows the system to maintain some electricity generation continuity while avoiding the energy waste associated with continuous low-power inefficient conversion. The PV module returns to MPP during idle periods, ensuring optimal efficiency when conversion occurs.
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
This approach enhances the efficiency of solar panel systems by optimizing power conversion, reducing inefficiencies at low irradiance levels and facilitating rapid tracking of the MPP, leading to improved overall system performance and energy output.
Implementation Method 1
a means for storing energy from a DC input current
Implementation Method 2
a means for converting the DC input current to AC output current
Implementation Method 3
a second means for determining a difference in a first power measurement and a second power measurement, producing an error signal indicative of the difference
Data Source
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AI summary
A method and apparatus for converting DC input power to AC output power. The apparatus comprises means for storing energy from a DC input current, means for converting the DC input current to AC output current, means for causing the energy to be stored in and drawn from the means for storing during at least one storage and at least one burst period, respectively, the AC output current greater than the DC input current during the at least one burst period; a first means for determining a maximum power point (MPP) and operating the means for converting proximate the MPP; and a second means for determining a difference in a first and a second power measurement, producing an error signal indicative of the difference, and coupling the error signal to the first means to adjust at least one operating parameter of the means for converting to drive toward the MPP.