Resonant Power Converter Controller Using Variable PDM
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Solution Overview
Problem
Current power conversion techniques in information processing equipment face challenges such as poor reduced-load efficiency and low power density due to practical implementation issues and control complexities, particularly with resonant converters, which are reluctant to replace pulse-width modulated (PWM) converters despite their advantages.
Innovation Solution
A control technique for resonant converters that maintains high efficiency and load regulation by exciting the tank circuit with constant frequency, symmetrical voltage or current, and employs an alternative form of pulse density modulation (PDM) to achieve fast transient response with minimal filter size, enabling efficient operation across a wide load range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If traditional pulse density modulation (PDM) is applied to power converters, then high efficiency is achieved through pulsed operation and lossless switching, but size increases and transient performance deteriorates
Solution Approach 1:
The patent applies dynamics by making the PDM period variable rather than fixed. The control circuit dynamically adjusts the period between on-periods based on load conditions, allowing the converter to achieve fast transient response while maintaining high efficiency. This resolves the contradiction by enabling the system to adapt its timing characteristics to different operating conditions.
Solution Approach 2:
The patent changes the parameter of PDM period from a fixed value to a variable parameter that can be adjusted based on load requirements. By varying the period between on-periods, the system optimizes both efficiency and transient response performance, resolving the contradiction between these two opposing requirements.
2Loss of energy
If resonant converters are used instead of PWM converters, then near lossless switching and high switching frequency are achieved, but practical implementation issues increase size and control complexity
Solution Approach 1:
The patent applies self-service by using the resonant converter's own tank circuit characteristics to generate the switching signals. The control circuit leverages the natural resonance of the tank circuit to produce symmetrical square wave signals, eliminating the need for complex external control mechanisms and reducing overall system complexity while maintaining lossless switching.
Solution Approach 2:
The patent makes the tank circuit serve multiple functions: it acts as both the resonant element for lossless switching and the signal generator for controlling the switches. This multi-functionality reduces the need for separate control circuitry, thereby reducing device complexity while preserving the energy efficiency benefits.
3Loss of energy
If resonant converters are used instead of PWM converters, then near lossless switching and high switching frequency are achieved, but practical implementation issues lead to increased size
Solution Approach 1:
The patent merges the function of the tank circuit with the control signal generation function. By using the same tank circuit to both achieve lossless switching and generate the switching signals, the system eliminates the need for separate control components, thereby reducing overall converter size while maintaining 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
The solution achieves high efficiency and reduced filter size, overcoming the drawbacks of traditional PDM by allowing the converter to dictate on and off periods, maintaining zero-voltage or zero-current switching, and optimizing component usage at multi-megahertz frequencies, suitable for portable and mobile systems.
Implementation Method 1
exciting the tank circuit of the converter with a constant frequency, symmetrical voltage or current
Implementation Method 2
the primary switches achieve zero-voltage switching (ZVS), the rectifiers achieve zero-current switching (ZCS)
Implementation Method 3
the primary switches achieve zero-voltage switching (ZVS), the rectifiers achieve zero-current switching (ZCS)
Data Source
AI summary
This invention relates to circuits and methods for controlling a resonant power converter. Control of the power converter may comprise comparing an output voltage or current of the converter to at least one reference voltage or current; enabling primary side switching signals based on a first selected result of the comparison; and disabling primary side switching signals based on a second selected result of the comparison; wherein a primary side switching signal for each primary side switch includes at least one off-on-off transition.