Bidirectional DC/DC Converter Phase Shift Control
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Solution Overview
Problem
Conventional bidirectional DC/DC converters face challenges in preventing reverse current flow during power transmission, leading to increased reactive power and delayed response to changes in power direction or load variations, which hinders swift power adjustments.
Innovation Solution
A DC/DC converter design featuring full-bridge circuits with antiparallel diodes and a control circuit that calculates and adjusts the output duty cycle based on current differences, ensuring zero voltage switching and phase shift corrections to prevent reverse current flow and enhance response speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional bidirectional DC/DC converter control is used, then simple circuit configuration is achieved, but reverse current flow occurs causing increased reactive power and loss
Solution Approach 1:
The control circuit calculates an output duty cycle based on a difference current value between a current detection value and a current command value, implementing feedback control to prevent reverse current flow and reduce reactive power loss while maintaining simple circuit configuration
Solution Approach 2:
The invention changes the control parameter from simple on/off switching to duty cycle control based on current difference calculation, enabling prevention of reverse current flow without complicating the circuit structure
2Power
If conventional DC/DC converter control is used, then basic power transmission is achieved, but response delay occurs due to short-circuit prevention time
Solution Approach 1:
The control circuit calculates the output duty cycle in advance based on the current difference between detection value and command value, enabling swift power adjustments without waiting for short-circuit prevention periods to elapse
Solution Approach 2:
The invention implements dynamic duty cycle control that adjusts switching ratios in real-time based on current feedback, enabling rapid response to load variations and power direction changes while maintaining safe operation
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 effectively reduces losses by preventing reverse current flow over a wide voltage range, enabling swift and reliable power adjustments in response to load variations and changes in power direction.
Implementation Method 1
a transformer; a first converter unit formed by a full-bridge circuit including two bridge circuits each having a plurality of semiconductor switching elements... connected between the first DC power supply and a first winding of the transformer
Implementation Method 2
a first converter unit formed by a full-bridge circuit including two bridge circuits each having a plurality of semiconductor switching elements to which antiparallel diodes are respectively connected
Implementation Method 3
a second reactor connected on an AC input/output line of the second converter unit
Data Source
AI summary
In this DC/DC converter, a first switching circuit is connected between a first winding of a transformer and a DC power supply, and a second switching circuit is connected between a second winding and a battery. A control circuit includes a first circuit for performing feedback control so as to reduce a difference between a detected value and a command value of charge current, and a second circuit for correcting one of control input and output of the first circuit on the basis of the detected value and the command value. In charging the battery, the control circuit controls a phase shift amount of a first diagonal element in the first switching circuit and a phase shift amount of a second diagonal element in the second switching circuit relative to the drive phase of a first reference element in the first switching circuit.