CLLC Converter Frequency Compensation for Ripple-Stable Charging
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Solution Overview
Problem
Power converting apparatuses with CLLC resonant converters face issues due to the reflection of ripple components in DC voltage, affecting charging current stability and reducing the service life of electronic components.
Innovation Solution
A power converting apparatus with a first and second bridge switching circuit, a transformer circuit, and a switching frequency control circuit that generates a compensation frequency to adjust the switching frequency of the bridge switching circuits, reducing the ripple component influence through bandpass filtering and frequency control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a power factor correction circuit is used to increase the power factor value and provide DC voltage to a CLLC resonant converter, then the power factor is improved, but the ripple component in the DC voltage is reflected to the output terminal, affecting charging current stability
Solution Approach 1:
The patent employs a feedback mechanism where the switching frequency control circuit continuously monitors the DC voltage input to the CLLC resonant converter and dynamically adjusts the switching frequency in response to detected ripple components. This closed-loop control ensures that the converter maintains stable operation despite ripple variations from the power factor correction circuit, thereby resolving the contradiction between achieving high power factor and maintaining charging current stability
Solution Approach 2:
The patent changes the switching frequency parameter dynamically based on the detected ripple conditions. By adjusting the switching frequency in response to ripple amplitude variations, the system optimizes the operating point of the CLLC resonant converter to minimize the impact of ripple on output stability, thus resolving the contradiction between power factor improvement and current stability
2Ease of manufacture
If the amplitude of the ripple increases, then the power factor correction performance is improved, but the stress on the CLLC resonant converter increases, decreasing the service life of electronic components
Solution Approach 1:
The switching frequency control circuit uses feedback to detect ripple amplitude and dynamically adjusts the switching frequency to keep the CLLC resonant converter operating within safe stress limits. This prevents excessive stress on electronic components even when ripple amplitude increases, thereby extending component service life while maintaining power factor correction performance
Solution Approach 2:
The system transitions from a static switching frequency to a dynamic switching frequency that adapts in real-time to ripple conditions. This dynamic adjustment allows the converter to optimize performance while avoiding excessive stress on components, resolving the contradiction between power factor correction effectiveness and component longevity
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
Stabilizes the output current and voltage, thereby prolonging the service life of the power converting apparatus by effectively suppressing the ripple component's impact.
Implementation Method 1
The switching frequency control circuit performs bandpass filtering on the DC voltage according to a frequency of the input AC signal to generate a ripple signal with a ripple frequency
Implementation Method 2
The transformer circuit includes an input side circuit and an output side circuit, and the input side circuit is coupled to the first bridge switching circuit
Implementation Method 3
The resonant inductor and the resonant capacitor are connected in series between the secondary winding and the second bridge switching circuit
Data Source
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AI summary
A power converting apparatus (100) and a converting method thereof are provided. A power converting apparatus (100) includes a transformer circuit (108) and a bridge switching circuit coupled to an input side circuit (114) of the transformer circuit (108). A switching frequency control circuit (110) generates a compensation frequency (fcps) according to an input voltage of the bridge switching circuit and adjusts a switching frequency of the bridge switching circuit based on the compensation frequency (fcps).