Auxiliary Power Supply Switching for PV Inverter Night Operation
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Solution Overview
Problem
In photovoltaic power generation systems, there is a need for an efficient auxiliary power supply that can operate independently of solar power generation, such as at night, to drive inverters and other components, as existing solutions often result in unnecessary power consumption and electromagnetic interference (EMI) due to inefficient switching between power sources.
Innovation Solution
An auxiliary power supply device comprising a first unit powered by a photovoltaic module, a second unit powered by the grid, and a driving unit that controls the second unit based on the photovoltaic module's voltage, allowing efficient switching between the two sources to minimize unnecessary power consumption and EMI, with features like sensing, comparison, and feedback mechanisms to optimize operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the auxiliary power supply device uses a single power source that operates continuously, then the device can always provide auxiliary power, but unnecessary power consumption and EMI occur when the power source is not needed
Solution Approach 1:
The patent implements dynamic switching between different power sources (photovoltaic module and grid) based on real-time voltage conditions. The driving unit activates or deactivates the second auxiliary power supply unit according to whether the photovoltaic module voltage is above or below a threshold, allowing the system to adapt its power supply configuration to current conditions rather than operating continuously with a fixed configuration.
2Loss of energy
If the auxiliary power supply device switches between multiple power sources, then power efficiency is improved, but EMI is generated due to switching operations
Solution Approach 1:
The patent employs feedback control through the driving unit that continuously monitors the photovoltaic module voltage and adjusts the operation of the second auxiliary power supply unit accordingly. When the photovoltaic voltage is sufficient (above threshold), the feedback signal deactivates the second power supply unit, eliminating unnecessary switching and associated EMI. When voltage is insufficient (below threshold), the feedback signal activates the second unit to ensure continuous auxiliary power supply.
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 solution enables efficient generation of auxiliary power by switching off unused units, reducing power losses and improving EMI characteristics, ensuring reliable operation of power conversion devices regardless of solar power availability.
Implementation Method 1
a first auxiliary power supply unit which receives power applied from a photovoltaic module and generates auxiliary power therefrom
Implementation Method 2
a sensing unit for sensing a voltage of the photovoltaic module
Implementation Method 3
a comparator for comparing the sensed voltage of the photovoltaic module with a reference voltage
Data Source
AI summary
The present invention relates to an auxiliary power supply device for generating auxiliary power of a power conversion device, the auxiliary power supply device comprising: a first auxiliary power supply unit which receives power applied from a photovoltaic module and generates auxiliary power therefrom; a second auxiliary power supply unit which receives power applied from a grid and generates auxiliary power therefrom; and a driving unit which can selectively drive the second auxiliary power supply unit according to the magnitude of voltage of the photovoltaic module. Accordingly, the present invention has an advantage in that an auxiliary power supply can be normally operated even in an environment where photovoltaic power generation is not performed.