Push-Pull Converter Triangular Modulation and Asymmetric Secondary Circuit
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Solution Overview
Problem
Push-pull converters for electric vehicle charging face inefficiencies due to power losses from switching processes and require complex control methods to minimize these losses, particularly in the trapezoidal modulation method.
Innovation Solution
A push-pull converter design with a reduced number of switchable components and a novel modulation method that simplifies control by reducing the complexity of measurement technology, maintaining soft-switching operation across power ranges, and being robust to load fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the trapezoidal modulation method is used to control the push-pull converter, then the battery charging capacity can be adjusted across a broad power range, but power losses from switching processes occur and complex control methods are required
Solution Approach 1:
The patent changes the modulation parameter waveform from trapezoidal to triangular, which fundamentally alters the switching behavior. This parameter change enables continuous soft-switching operation across the entire power range, eliminating switching losses while maintaining broad charging capacity adjustment from 400W to 3300W.
Solution Approach 2:
Instead of using complex time-critical current detection to minimize switching losses in trapezoidal modulation, the patent inverts the approach by using a simplified modulation method that inherently achieves soft-switching without requiring complex control or detection mechanisms.
2Productivity
If the trapezoidal modulation method is used, then power transmission can occur in plateau phases, but a complex control method comprising time-critical current detection is necessary to minimize switching losses
Solution Approach 1:
The patent extracts and eliminates the complex time-critical current detection requirement from the control system. By using triangular modulation, the system achieves effective power transmission without needing the complicated control mechanisms that were necessary for trapezoidal modulation.
Solution Approach 2:
Changing the modulation waveform from trapezoidal to triangular fundamentally simplifies the control requirements. The triangular waveform naturally provides the necessary power transmission capability across different phases without requiring complex detection and control algorithms.
3Adaptability or versatility
If switching devices are used in both semi-bridge circuits, then bidirectional power flow is achieved, but the number of switchable components increases and control complexity increases
Solution Approach 1:
The patent introduces asymmetry in the secondary-side circuit configuration by using only one switching device in one semi-bridge circuit while using diodes in the other semi-bridge circuit. This asymmetric design maintains bidirectional power flow capability while reducing the total number of active switching components and simplifying control.
Solution Approach 2:
Instead of duplicating full switching circuits in both semi-bridges, the patent uses diodes (passive components) to replicate the functionality of one side, eliminating the need for a second active switching device while maintaining bidirectional operation capability.
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 reduces switching losses, simplifies control, and ensures efficient operation in both high and low power ranges, maintaining robustness against load changes without the need for additional safety measures.
Implementation Method 1
a transformer with a primary-side winding and a secondary-side winding, said transformer being designed to receive the first AC voltage on the primary-side winding and to generate a second AC voltage on the secondary-side winding
Data Source
AI summary
A push-pull converter including a primary-side input converter circuit with a plurality of primary-side switching devices in a full-bridge circuit including a transformer being designed to receive the first AC voltage on a primary-side winding and to generate a second AC voltage on a secondary-side winding. The push-pull converter includes a secondary-side output converter circuit to convert the second AC voltage into an output DC voltage, including a first semi-bridge circuit, said semi-bridge circuit including a first secondary-side switching device, a second secondary-side switching device, and a first center tap connected to a first connection of the secondary-side winding. The secondary-side output converter circuit includes a second semi-bridge circuit which includes a first secondary-side diode, a second secondary-side diode, and a second center tap connected to a second connection of the secondary-side winding, said second semi-bridge circuit not including a switchable component.