DC-DC Converter ZVS Control via Primary Side Power Detection
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Solution Overview
Problem
Existing DC-DC converters that implement zero voltage switching (ZVS) require complex circuit configurations and control methods, making it difficult to improve productivity and reduce costs.
Innovation Solution
A DC-DC converter design incorporating a first and second full-bridge circuit, a transformer, and an inductance component, with a control circuit capable of executing output angle modulation, frequency modulation, and phase control modes to simplify switching control and reduce switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If power detection and switching control are implemented on both primary and secondary sides to achieve ZVS operations, then switching losses are reduced and high-efficiency power transfer is achieved, but circuit configuration complexity increases and productivity decreases
Solution Approach 1:
The patent extracts the power detection function from the secondary side and implements it only on the primary side. The control method uses primary side power detection combined with duty cycle adjustment to achieve ZVS operations, eliminating the need for secondary side power detection circuits and simplifying the overall system configuration while maintaining energy efficiency.
Solution Approach 2:
The primary side full-bridge circuit is designed to perform multiple functions: power detection, switching control, and ZVS operation achievement. By making the primary side circuit multi-functional, the patent eliminates the need for separate secondary side detection and control circuits, thereby reducing overall system complexity while maintaining high-efficiency power transfer.
2Reliability
If dual-side power detection and duty cycle adjustment are implemented to minimize power difference, then ZVS operations are achieved, but control complexity increases
Solution Approach 1:
The patent removes the secondary side power detection and control functions, retaining only primary side power detection. The control strategy uses primary side duty cycle adjustment to achieve ZVS operations, significantly simplifying the control system while maintaining reliable ZVS operation through careful duty cycle management.
Solution Approach 2:
The patent changes the control parameter from dual-side duty cycle adjustment to primary side duty cycle adjustment only. By modifying the control strategy to rely solely on primary side parameters (power detection and duty cycle), the system achieves ZVS operations with reduced control complexity and fewer required sensors.
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 proposed solution allows for ZVS operations with simple control, suppressing switching losses and heat generation, particularly in the inductor, while maintaining high-efficiency power transfer.
Implementation Method 1
a transformer (T) including a first winding (n1) and a second winding (n2), the first winding being connected to the first full-bridge circuit, and the second winding being connected to the second full-bridge circuit and magnetically coupled to the first winding
Data Source
AI summary
A DC-DC converter has a configuration in which a first full-bridge circuit and a second full-bridge circuit are connected via a transformer and an inductor. A control circuit controls soft switching of each switching element in the first full-bridge circuit and the second full-bridge circuit. An inductor current flowing through an equivalent inductor at a time of switching of turning on or off each switching element is greater than or equal to a threshold current, the equivalent inductor being equivalent to the transformer and the inductor. The control circuit outputs predetermined power by changing a voltage output period of the first full-bridge circuit and a voltage output period of the second full-bridge circuit while fixing the switching frequency and keeping constant a polarity inversion period in which the output of the second full-bridge circuit and the output of the first full-bridge circuit have reverse polarities. This enables performing ZVS operations by simple control and reducing switching losses.