Single-Stage Bidirectional Charger Without Electrolytic Capacitors
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Solution Overview
Problem
Conventional electric vehicle on-board chargers with a modular 2-stage structure have limitations in power density, efficiency, volume, and service life due to the use of electrolytic capacitors, and single-stage circuits without electrolytic capacitors face performance issues in wide input/output voltage ranges and require additional components for decoupling.
Innovation Solution
A three-phase and single-phase two-way charger with a single-stage AC-DC converter circuit that integrates multiple components into one core, reducing the number of switching elements and using relays and capacitors for decoupling without separate switches or inductors, enabling direct current charging and improved performance across a wide voltage range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a modular 2-stage structure is used for the charger, then the charging function can be provided, but the power density is limited and the volume is large due to a large number of elements
Solution Approach 1:
The charger is divided into three independent modules (first module, second module, third module), each capable of processing one phase of three-phase power or handling single-phase power. This segmentation allows the system to achieve high power density by distributing components across modules while maintaining functional completeness.
Solution Approach 2:
Each module is designed with multi-functionality to handle both three-phase and single-phase power inputs. The modules can operate independently or in combination, providing universal charging capability that eliminates the need for separate circuits for different power types, thereby reducing overall element count while maintaining high power density.
2Duration of action of stationary object
If electrolytic capacitors are used in the charger, then the charging circuit can be implemented, but the service life is short and the volume is large
Solution Approach 1:
The invention extracts and removes electrolytic capacitors from the charging circuit entirely. By eliminating these components that have limited service life and occupy significant volume, the patent achieves extended charger lifespan and reduced size while maintaining functional performance through alternative circuit design.
Solution Approach 2:
The patent replaces short-lived electrolytic capacitors with long-life solid-state components and circuit topologies that do not require capacitors for basic functionality. This substitution eliminates the need for periodic replacement and reduces volume, directly addressing the service life and size constraints.
3Productivity
If a single-stage structure without electrolytic capacitors is used, then the power density and efficiency are improved, but the performance is poor in wide input/output voltage range and a separate decoupling circuit is required
Solution Approach 1:
The patent implements dynamic voltage adaptation by enabling each module to independently adjust its operation based on input voltage conditions. The modules can dynamically switch between operating modes to handle wide voltage ranges, maintaining high efficiency while adapting to different power sources without requiring separate decoupling circuits.
Solution Approach 2:
The invention changes operational parameters (switching frequencies, voltage levels, current distribution) across the three modules to accommodate wide input/output voltage ranges. By dynamically adjusting these parameters, the system maintains high charging efficiency while achieving versatility across different voltage conditions without additional decoupling circuitry.
4Reliability
If many magnetic bodies are used in the charger, then the charging function can be provided, but the volume and manufacture cost increase
Solution Approach 1:
The patent merges multiple magnetic components (inductors, transformers) into integrated magnetic structures within each module. By combining these functions into unified magnetic bodies, the invention reduces the total volume of magnetic materials while maintaining the reliability of charging operations through consolidated component design.
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 solution provides high efficiency, high density, and reliability with reduced volume and cost, enabling compatibility with single-phase and three-phase power and extending the service life of the charger.
Implementation Method 1
an AC-DC converter connected to an output terminal of each inductor of the noise removal unit to convert an output signal of each inductor into the direct current form
Implementation Method 2
an inverter connected to an output terminal of the ripple removal unit to convert the external power of low frequency component into an alternating current form of high frequency component
Implementation Method 3
a transformer connected to an output terminal of the capacitor to pass an output signal of the capacitor
Implementation Method 4
a ripple removal unit provided with inductors connected in parallel to a first end of an external power supply, which is supplied through the first and second relay switches, to remove a ripple component of the external power
Data Source
AI summary
The present technology discloses a three-phase and single-phase two-way charger. According to a specific example of the present invention, a battery charger having a single-stage structure for a combined use of single-phase and three-phase is implemented without an electrolytic capacitor which lowers the reliability and charging efficiency, to enable a compatible use of single-phase and three-phase external power sources, and to improve charging efficiency and the performance in a wide input/output voltage range by a reduced number of switching elements and a soft switching operation of the switching elements and thus improve the reliability and lifetime. A lightweight charger can be realized by integrating, into a core, at least two of an inductor for removing ripples of the battery charger, a primary side and a secondary side of a transformer, and an inductor for removing noise.