Multi-Phase Isolated Resonant Converter for Wide Voltage Range
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Solution Overview
Problem
Resonant converters face limitations in achieving a wide input/output voltage range due to large conduction losses and temperature increases caused by high RMS currents, which restrict their maximum power delivery capability, especially in high-power applications like electric vehicles and data centers.
Innovation Solution
The implementation of a multi-phase isolated resonant converter with a controller using a combination of variable switching frequency, duty ratio, and delay-time control, allowing for step-up voltage conversion ratio and reduced switching frequency range, thereby minimizing driving and switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If resonant converters operate at high power levels, then power delivery capability increases, but conduction losses and temperature increases occur due to high RMS currents
Solution Approach 1:
The patent divides the converter into multiple phases (dual-phase or multi-phase configuration), where each phase handles a portion of the total power. This segmentation reduces the RMS current per phase while maintaining total power delivery capability, thereby reducing conduction losses and thermal stress on individual components.
Solution Approach 2:
The patent introduces phase shifting between primary and secondary sides as an additional control dimension. By controlling the phase difference between primary and secondary switchings, the converter can regulate output voltage while distributing current more evenly across phases, reducing peak currents and associated conduction losses.
2Power
If resonant converters operate at high power levels, then power delivery capability increases, but temperature increases occur due to high RMS currents
Solution Approach 1:
The multi-phase configuration segments the thermal load across multiple parallel paths. Each phase operates at lower current levels, generating less heat individually, and the distributed architecture improves overall thermal management and reduces peak temperatures.
3Adaptability or versatility
If conventional resonant converters are used, then simple control is maintained, but wide input/output voltage range cannot be achieved
Solution Approach 1:
The patent implements dynamic control where the phase shift between primary and secondary sides is continuously adjusted based on the desired voltage conversion ratio. This dynamic phase control enables the converter to adapt to wide input/output voltage ranges while maintaining efficient operation across different operating conditions.
Solution Approach 2:
The patent changes the operating parameters by introducing controllable phase shift as an additional degree of freedom. By varying the phase difference between primary and secondary switchings, the converter can achieve different voltage conversion ratios, expanding its adaptability range.
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 a wider range of voltage conversion ratios, reduces conduction losses, and enhances the power delivery capability of resonant converters, addressing the limitations of conventional resonant converters in high-power applications.
Implementation Method 1
a resonant converter uses a resonant-tank circuit to shape voltage or current waveforms, or both, to minimize switching losses and to allow high frequency operations without compromising conversion efficiency
Implementation Method 2
the resonant-tank circuit includes resonant inductor L P and capacitors C P and C S connected in series through a transformer TR
Implementation Method 3
In order to minimize conduction losses, low on-resistance metal-oxide-semiconductor field effect transistors (MOSFETs) can be utilized as the secondary side rectifiers instead of diodes
Data Source
Figure 1A~1B
Figure 2A~2B
Figure 3A~3B
AI summary
The present disclosure provides a single- and multi-phase DC/DC converter (300) and a control method thereof that can offer a wide range of voltage conversion ratio by substantially reducing the switching frequency (fS) range, thereby resulting in performance improvement. Reduction in the switching frequency range is achieved by controlling the output voltage or current (VOUT, IOUT) with a combination of variable duty ratio (D), variable frequency, and delay-time control.