DC/DC Converter Reactor Step-Up Ratio Extension
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Solution Overview
Problem
Existing DC/DC converters that perform both step-up and step-down operations using a single transformer face limitations, as the transformation ratio set for step-down operations restricts the ability to perform step-up operations at a ratio larger than the transformer's step-up ratio, especially when the high-voltage battery's voltage decreases.
Innovation Solution
The DC/DC converter employs a transformer with a reactor to enable step-up operations beyond the transformer's step-up ratio by using the reactor to store and release magnetic energy, allowing the voltage of the low-voltage battery to be increased even when the high-voltage battery's voltage is at its minimum, and utilizes MOSFETs with parasitic diodes for efficient switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the transformation ratio of the transformer is set in consideration of step-down operation, then step-down operation can be performed effectively, but step-up operation at a transformation ratio larger than the set transformation ratio becomes impossible
Solution Approach 1:
The reactor is designed to serve multiple functions: it enables step-up operation beyond the transformer's rated ratio, allows direct coupling with the high-voltage battery when not needed, and provides inrush current suppression. This multi-functionality resolves the contradiction by making the system adaptable to both step-down and extended step-up operations without requiring separate components for each function.
Solution Approach 2:
The system dynamically switches between different operational modes by controlling the coupling and decoupling of the reactor with the high-voltage battery. During step-up operation, the reactor is coupled to extend the transformation ratio; during normal operation, it is decoupled to maintain the transformer's rated performance. This dynamic reconfiguration allows the system to adapt its transformation ratio based on operational requirements.
2Device complexity
If a single transformer is used for both step-down and step-up operations, then device complexity is reduced, but the transformation ratio is restricted to be equal for both operations
Solution Approach 1:
The reactor is designed to serve multiple functions: it enables step-up operation beyond the transformer's rated ratio, allows direct coupling with the high-voltage battery when not needed, and provides inrush current suppression. This multi-functionality resolves the contradiction by making the system adaptable to both step-down and extended step-up operations without requiring separate components for each function.
Solution Approach 2:
The system dynamically switches between different operational modes by controlling the coupling and decoupling of the reactor with the high-voltage battery. During step-up operation, the reactor is coupled to extend the transformation ratio; during normal operation, it is decoupled to maintain the transformer's rated performance. This dynamic reconfiguration allows the system to adapt its transformation ratio based on operational requirements.
3Use of energy by moving object
If the high-voltage battery voltage decreases to minimum value, then energy availability is reduced, but the low-voltage battery still needs to be charged
Solution Approach 1:
The system changes the transformation ratio parameter dynamically by coupling the reactor during step-up operation. When the high-voltage battery voltage is at its minimum, the reactor is coupled to achieve a higher effective transformation ratio, ensuring that the stepped-up voltage remains sufficient to charge the low-voltage battery. This parameter adjustment maintains charging capability despite varying input voltage conditions.
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
Enables efficient step-up and step-down operations, ensuring the low-voltage battery can be charged and powered even when the high-voltage battery's voltage is at its minimum, and prevents inrush currents by charging a smoothing capacitor before switching relays, effectively managing voltage ratios and current flow.
Implementation Method 1
employs a transformer with a reactor to enable step-up operations beyond the transformer's step-up ratio by using the reactor to store and release magnetic energy
Implementation Method 2
The DC/DC converter includes a transformer, a first switch element, a first diode, a first capacitor, a second switch element, a second diode, a second capacitor
Data Source
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AI summary
A DC/DC converter is able to step down a voltage value of a high-voltage battery, and is able to step up a voltage value of a low-voltage battery. The low-voltage battery is a battery that provides a lower voltage value than the high-voltage battery. The DC/DC converter includes a transformer, a third diode and a reactor. The transformer includes a first coil and a second coil. The first coil is connected to the low-voltage battery. The second coil is connected to the high-voltage battery. An anode of the third diode is connected to one end of the first coil. One end of the reactor is connected to a cathode of the third diode, and the other end of the reactor is connected to a positive electrode terminal of the low- voltage battery.