Bi-directional DC-to-DC Converter Resonant Control
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Solution Overview
Problem
Conventional bi-directional DC-to-DC converters face challenges in efficiently managing wide voltage ranges, particularly in stepping down voltages below a certain minimum value, and are unable to perform effective bi-directional voltage conversion with stability when voltage varies with charge or discharge states.
Innovation Solution
The DC-to-DC converter employs a control circuit that adjusts switching frequency and pulse waveforms to manage voltage conversion, using a resonant circuit with a transformer having a 1:1 turns ratio, allowing for both step-up and step-down operations by controlling the resonant frequency and duty cycle, thereby stabilizing output voltage across varying input voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional bi-directional DC-to-DC converter uses fixed switching frequency and standard voltage conversion topology, then the circuit structure is simple, but it cannot effectively manage wide voltage ranges or step down voltages below a certain minimum value
Solution Approach 1:
The patent implements dynamic switching frequency adjustment based on voltage conditions. The control circuit detects voltage levels and dynamically changes the switching frequency to optimize performance across different operating conditions, enabling the converter to handle wide voltage ranges including step-down operations below minimum voltage thresholds
Solution Approach 2:
The patent changes the switching frequency parameter adaptively according to the voltage conversion ratio and operating mode. By adjusting this critical parameter, the converter achieves optimal efficiency and voltage control across the full operating range without requiring complex additional circuitry
2Reliability
If the converter operates with fixed duty cycle and switching frequency, then the control system is simple, but it cannot maintain stable output voltage when input voltage varies with charge or discharge states
Solution Approach 1:
The patent employs a feedback control mechanism where the control circuit continuously monitors the output voltage and adjusts the duty cycle and switching frequency accordingly. This closed-loop control ensures stable output voltage despite variations in input voltage during charge and discharge cycles
Solution Approach 2:
The control system dynamically adjusts both duty cycle and switching frequency based on real-time voltage conditions. This dynamic adaptation allows the converter to maintain optimal performance and voltage stability across varying operating conditions without requiring overly complex control architecture
3Productivity
If the converter uses high switching frequency to improve response speed and voltage control, then voltage conversion efficiency improves, but switching losses increase
Solution Approach 1:
The patent dynamically adjusts the switching frequency based on the specific operating conditions and voltage conversion requirements. The control circuit selects optimal frequency levels that balance response speed and switching losses, using higher frequencies when fast response is needed and lower frequencies when efficiency is prioritized
Solution Approach 2:
The switching frequency parameter is changed adaptively according to the voltage conversion ratio and load conditions. This parameter optimization minimizes switching losses while maintaining adequate voltage conversion speed, achieving the best compromise between productivity and energy efficiency
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 approach enables efficient bi-directional voltage conversion, maintaining stability and reducing losses by adjusting switching frequency and duty cycle, allowing the converter to handle wide voltage ranges and ensure reliable operation during charging and discharging.
Implementation Method 1
LC resonant circuit 115 is inserted between a high-voltage-side winding of transformer 109 and high-voltage-side terminals 105 and 107
Implementation Method 2
Transformer 109 is connected between low-voltage-side terminals 101 and 103 and high-voltage-side terminals 105 and 107
Data Source
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AI summary
A DC to DC converter includes: first and second switching elements connected in series at a first connection point between a first input/output terminal and a first ground terminal; third and fourth switching elements connected in series at a second connection point between the first input/output terminal and the first ground terminal; a resonant capacitor and a resonant inductor connected in series between the first and second connection points; fifth and sixth switching elements connected in series at a third connection point between a second input/output terminal and a second ground terminal; seventh and eighth switching elements connected in series at a fourth connection point between the second input/output terminal and the second ground terminal; a transformer; and a control circuit. The transformer has a primary winding connected in series to the resonant capacitor and the resonant inductor between the first and second connection points, and a secondary winding connected in series between the third and fourth connection points. The control circuit is operable to adjust the pulse waveforms for switching the fifth to eighth switching elements when voltage at the second input/output terminal is stepped down and output from the first input/output terminal.