Power Converter Mode Switching for Voltage Control
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Solution Overview
Problem
The existing power supply systems lack a flexible voltage control function between power storage units and an electric power line, making it difficult to maintain efficient operation across varying load conditions, and existing power converters do not adequately describe the selection of operation modes for efficient power conversion.
Innovation Solution
A power supply system with a power converter connected across multiple DC power supplies and an electric power line, featuring a control device that selectively controls operation modes, including series direct connection and voltage controlling modes, to adjust output voltage and optimize efficiency by managing the charging and discharging of DC power supplies based on voltage commands and load conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the power supply system uses series direct connection mode to maintain efficiency, then energy loss is reduced, but voltage control flexibility deteriorates when supply voltage decreases
Solution Approach 1:
The power converter dynamically switches between series direct connection mode and voltage controlling mode based on real-time voltage conditions. When supply voltage is sufficient, series direct connection mode is used for efficiency; when voltage decreases, voltage controlling mode activates to restore voltage levels, providing adaptive response to changing conditions
Solution Approach 2:
The system changes operational parameters by switching connection modes: in series direct connection mode, the full series voltage is applied; in voltage controlling mode, the connection is reconfigured to provide voltage boosting through the power converter, thereby adjusting the effective voltage parameter according to load requirements
2Reliability
If the power converter operates in voltage controlling mode to maintain sufficient voltage, then voltage supply reliability is improved, but system complexity increases
Solution Approach 1:
The power converter is designed with multi-functionality to perform both series direct connection operation and voltage controlling operation using the same hardware components. This universal design avoids the need for separate voltage boosting equipment, maintaining reliability while limiting complexity growth
Solution Approach 2:
The power converter acts as an intermediary device that mediates between the series-connected power supplies and the load. It provides voltage control functionality without requiring direct modification of the power supply units themselves, isolating complexity to a single controllable component
3Loss of energy
If the system switches between series connection and parallel connection modes to optimize efficiency, then energy efficiency is improved, but control complexity increases
Solution Approach 1:
The control device continuously monitors voltage levels and power supply conditions, using feedback signals to automatically determine when to switch between series direct connection mode and voltage controlling mode. This closed-loop control optimizes efficiency while automating the decision-making process to manage control complexity
Solution Approach 2:
The control system automatically manages mode switching based on predetermined voltage thresholds and operational conditions without requiring manual intervention. The system self-regulates by detecting voltage drops and autonomously transitioning to voltage controlling mode, then returning to series direct connection mode when conditions improve
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 system improves overall efficiency by allowing flexible selection of operation modes, ensuring sufficient voltage supply to the load and minimizing losses across different usage conditions, while effectively managing the power distribution between DC power supplies.
Implementation Method 1
the power converter is configured to control an output voltage on the electric power line by operating with one operation mode being selectively applied among a plurality of operation modes different in a manner of power conversion between the plurality of DC power supplies and the electric power line
Data Source
AI summary
A power converter has a series direct connection mode of keeping on/off of a plurality of switching elements to maintain the state where first and second DC power supplies different in amount of voltage change with respect to input/output of the same amount of electric power are connected in series with an electric power line connected to a load, and a voltage controlling mode of controlling an output voltage on the electric power line to be a voltage command value by controlling on/off of the plurality of switching elements. In the voltage controlling mode, between time tx and ta, the sum of voltages of the first and second DC power supplies is matched with the voltage command value by controlling the output voltage by means of charging/discharging between the first and second DC power supplies. After time ta, the series direct connection mode is applied.