Resonant DC/DC Converter Phase-Shift Control for Wide Voltage Range
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Solution Overview
Problem
Resonant DC/DC converters face a narrow output voltage range, particularly under light load or no load conditions, where the output voltage is restricted by the voltage gain, leading to inefficiencies and increased losses.
Innovation Solution
A resonant DC/DC converter is designed with a phase-shift circuit and a control unit that adjusts the phase shifting angle between 0° and 180° based on output sampling signals, expanding the output voltage range by incorporating a phase-shift circuit within the power conversion unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the switching frequency is increased to obtain smaller voltage gain under light load, then the output voltage range is extended, but the magnetic core loss and conduction loss increase, decreasing efficiency
Solution Approach 1:
The patent applies dynamics by making the duty ratio variable rather than fixed at 50%. The control unit dynamically adjusts the duty ratio of the switching tubes based on load conditions, enabling the converter to maintain optimal efficiency across a wide output voltage range without relying solely on high switching frequencies that increase losses.
2Adaptability or versatility
If the inductance coefficient is reduced to make the voltage gain curve sharper, then smaller high-frequency gain is obtained, but the magnetic core loss and conduction loss increase, decreasing efficiency
Solution Approach 1:
The patent uses dynamic duty ratio adjustment to control the voltage gain instead of relying on a fixed inductance coefficient design. This allows the system to achieve sharp voltage gain control when needed without permanently increasing losses, as the duty ratio can be optimized for each operating condition.
3Adaptability or versatility
If intermittent control mode is used to widen the lower limit of output voltage, then the output voltage range is extended, but the output voltage ripple increases and switching loss of hard conducting increases
Solution Approach 1:
The patent employs continuous duty ratio modulation instead of intermittent control. By dynamically adjusting the duty ratio within a continuous range, the converter can extend the output voltage range while maintaining stable output voltage and avoiding the high ripple and hard switching losses associated with intermittent operation modes.
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 solution effectively widens the output voltage range and reduces losses by optimizing the phase shifting control mode, addressing the limitations of existing resonant converters.
Implementation Method 1
the resonant converter has many advantages, but it still has some drawbacks such as narrow output voltage range
Implementation Method 2
the phase-shift circuit comprises at least a pair of first switching elements S1, S2 and a phase-shift inductance La
Data Source
AI summary
Disclosed is a resonant DC/DC converter, comprising a DC source unit, a power conversion unit, a control unit and an output rectification unit, wherein the power conversion unit comprises a resonance circuit and at least a phase-shift circuit, the phase-shift circuit comprises at least a pair of first switching elements S1, S2 and a phase-shift inductance La, one end of the phase-shift inductance is connected with the bridge node of the first switching element S1, S2, and the other end is coupled to the resonance circuit; the control unit drives each switching element of the power conversion unit, and the switching frequency and the phase shifting angle of the first switching element are calculated according to the feedback signals of the output rectification unit. Further, the resonant DC/DC converter is applicable to series connection solution, which can be extended to more than two circuits in parallel, to achieve intersection; and a phase-shift circuit is added in the resonant DC/DC converter and by adjusting the phase shift angle to drop the output voltage and achieve the adjustment of a wide range of output voltage of the resonant circuit.