Auxiliary Power Supply Control for Weak-Source Power Conversion
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Solution Overview
Problem
In weak-source scenarios, such as early morning, evening, or cloudy and rainy days, photovoltaic modules produce weak output energy, leading to instability in downstream devices due to repeated startups and failures of auxiliary power supplies.
Innovation Solution
A power conversion device with an auxiliary power supply, load, and controller that dynamically adjusts connections and voltages based on voltage thresholds to stabilize the system, preventing repeated startups and enhancing reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the downstream device is connected when the output voltage of the photovoltaic module is within the normal startup voltage range, then the downstream device can be started, but the input voltage of the downstream device is pulled down causing the auxiliary power supply to fail and the device cannot work properly
Solution Approach 1:
The controller detects whether the input voltage meets the startup condition before the downstream device is connected. Only when the input voltage is sufficient to support the auxiliary power supply does the controller allow connection. This preliminary detection and conditional connection prevents the voltage pull-down effect that causes auxiliary power supply failure.
2Reliability
If the output voltage of the photovoltaic module is weak in the morning, evening, or on cloudy days, then the downstream device cannot be started, but connecting it anyway causes repeated startups and failures of the auxiliary power supply
Solution Approach 1:
The controller continuously monitors the input voltage and provides feedback to determine whether the auxiliary power supply can operate stably. When the input voltage is insufficient (weak source scenario), the controller prevents connection to avoid repeated startups and failures. This feedback mechanism ensures the auxiliary power supply only operates when conditions are favorable.
3Ease of operation
If the downstream device is connected with insufficient input energy, then the device can be connected, but the auxiliary power supply cannot work properly and must restart repeatedly
Solution Approach 1:
Before connecting the downstream device, the controller performs a preliminary detection to determine whether the input voltage meets the startup condition. This preliminary action ensures that connection only occurs when the input energy is sufficient to support stable operation of the auxiliary power supply, preventing repeated startups and failures.
Data Source
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AI summary
This application provides a power conversion device and a method for controlling the power conversion device. An input end and an output end of the power conversion device are respectively connected to a direct current power supply and a device load. The power conversion device includes an auxiliary power supply, a first load, a power conversion circuit, and a controller. When an output voltage of the auxiliary power supply in operation is greater than or equal to a first voltage threshold, the controller controls the first load to be connected to the power conversion device, so that the output voltage of the auxiliary power supply decreases. When the output voltage of the auxiliary power supply is greater than or equal to a second voltage threshold after the first load is connected to the power conversion device, the controller controls the first load to be disconnected from the power conversion device, and controls the output voltage of the auxiliary power supply to be a first target output voltage. The first voltage threshold is less than the second voltage threshold. According to this application, stability of the auxiliary power supply in operation may be improved.