Bidirectional DC/DC Converter Voltage Range Expansion
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Solution Overview
Problem
Bidirectional DC/DC converters require wide input and output voltage ranges to efficiently manage the varying battery voltages of electric drive vehicles and commercial power systems, but existing solutions struggle to bidirectionally boost and step down voltages effectively across these ranges.
Innovation Solution
A bidirectional DC/DC converter configuration that includes switching circuits, transformers, rectifying elements, capacitors, and short circuits, controlled by a controller to switch between full-wave rectification and full-wave voltage doubling rectification operations based on voltage magnitude, allowing for bidirectional voltage conversion and expanded voltage ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a bidirectional DC/DC converter uses a transformer with half-bridge and full-bridge switching circuits for electrical insulation, then reliability is improved, but the voltage conversion range is limited and device complexity increases
Solution Approach 1:
The patent employs dynamic switching between half-bridge and full-bridge modes based on voltage magnitude. When input voltage exceeds output voltage, the system switches to full-bridge mode for voltage step-down; when input voltage is lower, it switches to half-bridge mode for voltage step-up. This dynamic operation enables the converter to adapt to wide voltage ranges while maintaining electrical insulation through the transformer.
Solution Approach 2:
The converter circuit is designed to perform multiple functions using the same basic components. The switching circuits can operate in both half-bridge and full-bridge modes, and the rectifier circuits can function in both voltage-doubling and non-voltage-doubling configurations. This multi-functionality allows a single device to handle various voltage conversion scenarios without requiring separate circuits for each mode.
2Adaptability or versatility
If the bidirectional DC/DC converter operates with fixed switching circuit configuration, then device complexity is reduced, but it cannot efficiently handle wide voltage ranges
Solution Approach 1:
The control system dynamically adjusts the switching circuit configuration based on real-time voltage detection. When the input voltage is higher than the output voltage, the system activates full-bridge switching; when input voltage is lower, it switches to half-bridge mode. This dynamic reconfiguration enables efficient operation across wide voltage ranges without requiring multiple fixed circuits.
Solution Approach 2:
The patent changes operational parameters (switching mode, rectifier configuration) based on voltage magnitude conditions. By detecting voltage levels and adjusting the operating mode accordingly, the system optimizes performance for each voltage range while using the same physical hardware, thereby avoiding the need for multiple dedicated circuits.
3Adaptability or versatility
If voltage doubling rectification is always used, then output voltage range is expanded, but loss of energy increases due to additional switching operations
Solution Approach 1:
The rectifier circuit dynamically switches between voltage-doubling and non-voltage-doubling modes based on the relationship between input and output voltages. When input voltage is lower than output voltage requirements, voltage-doubling mode is activated to expand the output range. When input voltage is sufficient, the system operates in non-voltage-doubling mode to minimize switching losses and improve efficiency.
Solution Approach 2:
The system changes the rectification mode parameter based on voltage conditions. By detecting whether voltage doubling is necessary to meet output requirements, the control system adjusts the rectifier operation accordingly, optimizing the balance between voltage range coverage and energy efficiency for each operating condition.
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
Enables efficient bidirectional voltage conversion across wide input and output voltage ranges, supporting both charging and discharging operations of electric drive vehicles by boosting and stepping down voltages as needed, thereby enhancing the functionality of power conditioners in V2H systems.
Implementation Method 1
Power transfer between the first conversion circuit and the second conversion circuit is performed through a transformer
Implementation Method 2
a full-wave rectification operation of applying a full-wave rectification voltage, resulting from full-wave rectification of a voltage across the second winding, to the series circuit of the third and fourth capacitors
Data Source
AI summary
In a discharging operation of a vehicle storage battery, a controller switches between a full-wave rectification operation of full-wave rectify a voltage across a second winding while maintaining a second short circuit in an open state, and a full-wave voltage doubling rectification operation of full-wave voltage doubling rectify a voltage across second winding while maintaining second short circuit in a closed state, based on magnitude relationship between DC voltage across first terminals and DC voltage across second terminals. In a charging operation, controller switches between a full-wave rectification operation of full-wave rectify a voltage across a first winding while maintaining a first short circuit in an open state, and a full-wave voltage doubling rectification operation of full-wave voltage doubling rectify a voltage across first winding while maintaining first short circuit in a closed state, based on magnitude relationship between DC voltage across first terminals and DC voltage across second terminals.