Two-Stage Switching Power Supply for Wide Input Voltage Efficiency
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Solution Overview
Problem
Existing DC-DC converters face inefficiency due to large voltage conversion ratios during steady states, especially when dealing with wide input voltage ranges, leading to increased inefficiency and power loss.
Innovation Solution
A two-stage switching power-supply device configuration featuring a non-insulated boost converter followed by an insulated bridge converter, utilizing a transformer with a primary and secondary winding, an alternating-current voltage generation circuit, and a rectifier circuit, with switching control circuits managing on-duty ratios and frequencies to maintain efficient voltage conversion across varying input voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the input voltage range is set large to handle instantaneous power failure, then the adaptability is improved, but the voltage conversion ratio becomes large during steady state causing efficiency to deteriorate
Solution Approach 1:
The power supply device is divided into two independent converter stages: a first converter (non-insulated type) and a second converter (series resonant type). Each stage handles a portion of the voltage conversion task, allowing the system to accommodate wide input voltage ranges while maintaining efficient operation at each stage independently.
Solution Approach 2:
The first converter acts as an intermediary stage between the input power source and the second converter. It conditions the input voltage to provide a stable intermediate voltage to the second converter, enabling the second converter to operate efficiently regardless of wide variations in input voltage.
2Adaptability or versatility
If the voltage conversion ratio is increased to handle low input voltage during power failure, then the adaptability is improved, but the switching losses increase causing efficiency to deteriorate
Solution Approach 1:
The total voltage conversion ratio is segmented between two converter stages. The first converter handles the initial voltage adjustment, and the second converter performs the final voltage conversion to the output. This segmentation allows each stage to operate at moderate conversion ratios, reducing switching losses in each stage while maintaining the ability to handle wide input voltage ranges.
3Power
If the on-duty ratio is increased to boost voltage during steady state, then the voltage conversion capability is improved, but the switching efficiency deteriorates due to increased switching frequency and losses
Solution Approach 1:
The voltage boosting function is distributed across two converter stages rather than relying on a single stage with high on-duty ratio. The first converter performs initial voltage elevation, and the second converter completes the voltage conversion, allowing both stages to operate with moderate on-duty ratios and maintain high switching efficiency.
Solution Approach 2:
The series resonant converter in the second stage operates at a fixed resonant frequency, providing periodic action that optimizes switching efficiency. This fixed frequency operation allows the converter to maintain high efficiency across varying load conditions and input voltages.
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 configuration allows for highly efficient voltage conversion even with large input voltage ranges, reducing switching losses and maintaining optimal performance by controlling on-duty ratios and frequencies, thus stabilizing output voltage and minimizing power loss.
Implementation Method 1
a rectifier circuit arranged to be connected to the secondary winding and rectify and output to the load a voltage induced in the secondary winding due to magnetic field coupling with the primary winding
Data Source
AI summary
A resonant converter circuit generates an output voltage from an input voltage by switching first and second FETs. A subsequent-stage switching control circuit alternately subjects the first and second FETs in the resonant converter circuit to on/off control with a fixed on-duty ratio and a fixed switching frequency. A boost converter circuit includes an inductor, a smoothing capacitor, and a third FET arranged to switch the energization of the inductor. A previous-stage switching control circuit subjects the third FET in the boost converter circuit to on/off control with a controlled on-duty ratio, and adjusts an output voltage to the resonant converter circuit.