Bi-directional DC/DC Converter With H-Bridge Modules
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Solution Overview
Problem
There is a need for advanced battery charging and testing systems that can efficiently manage power transfer between high and low voltage systems, particularly for electric vehicles and hybrid electric vehicles, to optimize charging efficiency and accurately simulate battery characteristics for testing purposes.
Innovation Solution
A bi-directional DC/DC converter system with multiple modules connected in parallel, featuring H-bridge configurations, transformer isolation, and hysteretic control, along with current sensing and control mechanisms to manage power flow and simulate battery behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If multiple modules are connected in parallel for power transfer, then power transfer efficiency is improved, but device complexity increases
Solution Approach 1:
The DC/DC converter is divided into multiple identical modules connected in parallel, where each module contains primary and secondary H-bridge circuits with transformers. This segmentation allows independent control of each module while achieving high power transfer efficiency through parallel operation, resolving the contradiction between efficiency improvement and complexity increase.
Solution Approach 2:
The system incorporates feedback control mechanisms where the controller receives information about the power transfer state and adjusts the switching of H-bridge circuits accordingly. This feedback enables optimized power transfer efficiency across different operating conditions while maintaining manageable system complexity through automated control.
2Manufacturing precision
If H-bridge configuration with transformer isolation is used, then power transfer control precision is improved, but device complexity increases
Solution Approach 1:
Transformers are introduced as intermediary components between the primary and secondary H-bridge circuits, providing galvanic isolation and enabling precise control of power transfer. The transformer isolation allows independent optimization of primary and secondary sides while maintaining precise control over the power transfer characteristics.
Solution Approach 2:
The system employs asymmetric H-bridge configurations where the primary and secondary sides have different numbers of switching devices and different control strategies. This asymmetry allows optimized control precision for each side's specific requirements while managing overall system complexity through specialized design.
3Speed
If hysteretic control is used for driving switches, then response speed is improved, but manufacturing precision requirements increase
Solution Approach 1:
The hysteretic control implements periodic switching action by comparing the output voltage with a reference voltage and toggling the switches accordingly. This periodic action provides fast response to load changes while the hysteresis band tolerates certain manufacturing variations in component parameters, resolving the contradiction between response speed and precision requirements.
4Measurement precision
If current sensing and feedback control are implemented, then battery simulation accuracy is improved, but device complexity increases
Solution Approach 1:
Current sensing components measure the actual current flowing to the battery, and this information is fed back to the controller which adjusts the power transfer to achieve accurate battery simulation. This feedback mechanism enables high simulation accuracy by continuously correcting for deviations from the target battery characteristics.
Solution Approach 2:
The system replaces complex mechanical battery testing equipment with electronic control and simulation circuitry. By using electronic current sensing and control algorithms, the system achieves accurate battery simulation without the mechanical complexity of physical test benches and measurement equipment.
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 enables efficient bi-directional power transfer and accurate battery simulation, optimizing charging efficiency and supporting the testing of electric vehicle batteries by precisely controlling current and voltage parameters.
Implementation Method 1
a transformer isolating the primary set of switches from the secondary set of switches
Data Source
AI summary
A bi-directional DC/DC converter includes at least one module having a module input for providing a bi-directional module input current, and a module output with an output inductor for providing a bi-directional module output current. A transformer has a primary winding wound around a transformer core and connected to the module input, and a secondary winding wound around the core and connected to the module output. A primary set of switches is connected in an H-bridge configuration between the module input and the primary winding. And, a secondary set of switches is connected in an H-bridge configuration between the module output and the secondary winding. A current sensing component senses the module output current. A hysteretic control drives the primary set of switches to control flux. The hysteretic control drives the secondary set of switches to control the module output current as a function of the sensed module output current.