Full-Bridge DC-DC Converter With Shared Return to Cut Winding Loss
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional isolated DC-DC converters face inefficiencies due to higher primary-winding area and losses, as well as increased losses in the secondary-side rectifier circuit, which can be attributed to the need for additional components and complex winding configurations.
Innovation Solution
A non-isolated full-bridge converter design with a primary-side inverter and secondary-side rectifier configuration, where the primary-side conduction paths share a common connection to the secondary winding, reducing the number of primary winding turns and minimizing current through the rectifier circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an isolated DC-DC converter configuration is used, then galvanic isolation between input and output is achieved, but primary-winding area and losses increase
Solution Approach 1:
The patent extracts the galvanic isolation function from the transformer coupling and implements it separately through a feedback control mechanism. The converter operates as a non-isolated full-bridge topology where the primary and secondary sides share a common ground, eliminating the need for magnetic coupling while maintaining output stability through voltage sensing and PWM control.
Solution Approach 2:
The patent introduces a feedback control system as an intermediary between the primary and secondary sides. A voltage sensor monitors the output voltage and feeds this information back to the controller, which adjusts the PWM duty cycle to maintain stable output without requiring galvanic isolation through transformer coupling.
2Reliability
If an isolated DC-DC converter configuration is used, then galvanic isolation is achieved, but the number of primary winding turns increases
Solution Approach 1:
The patent removes the transformer component entirely from the isolated converter configuration. The full-bridge inverter directly switches the input voltage without requiring primary windings, thereby eliminating the need for large transformer cores and reducing the overall converter size while maintaining the essential voltage conversion function through PWM control.
Solution Approach 2:
The control circuit acts as an intermediary that replaces the magnetic coupling function. By sensing the output voltage and regulating the PWM duty cycle, the system achieves the voltage transformation and isolation functions that traditionally required extensive primary windings in isolated converters.
3Reliability
If a conventional isolated converter design is used, then output isolation is achieved, but secondary-side rectifier losses increase
Solution Approach 1:
The patent extracts the rectification function from the secondary side and integrates it into the primary-side full-bridge inverter. The four switches in the full-bridge configuration perform both inversion and rectification functions, eliminating the need for separate secondary-side rectifier diodes or MOSFETs and their associated conduction and switching losses.
Solution Approach 2:
The patent merges the inversion and rectification functions into a single full-bridge circuit on the primary side. The same four switches that generate the AC voltage for the load also perform the rectification function through synchronous switching, reducing the total number of power semiconductor devices and minimizing cumulative losses.
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
This design reduces primary-winding area and losses, enhances efficiency by minimizing copper losses and rectifier power loss, thereby lowering costs and improving overall performance.
Implementation Method 1
a transformer having a primary winding and a secondary winding
Implementation Method 2
an output filter connected to an output side of the secondary winding for filtering converter output current to reduce a switching-related AC component
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A non-isolated converter includes a transformer having a primary winding and a secondary winding, a primary-side inverter, a secondary-side rectifier, and an output filter. The primary-side inverter is a full-bridge inverter providing two conduction paths for primary current during ON intervals of a switching cycle. The conduction paths are connected at a low-side common connection directly connected to the output side of the secondary winding, to provide the converter output current as the sum of the primary current and the secondary current during the ON intervals. Because the converter output includes a contribution from primary-side current due to the direct connection, certain advantages may be realized such as reduced primary-winding area/losses and reduced losses in the secondary-side rectifier.