Resonant Power Converter Control Using Rectified Current Ramp
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Solution Overview
Problem
Existing resonant power converters suffer from power loss and increased circuit complexity due to the use of resistors for voltage division, which also results in poor transient response capability.
Innovation Solution
A high-efficiency resonant power converter is designed using full-wave rectification of the resonant current signal to generate a ramp signal, which, along with a compensation signal, is used to control the switching of high-side and low-side transistors independently, enhancing transient response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resistors are used for voltage division to generate bias signals, then the resonant power converter can operate with proper transistor biasing, but additional power loss occurs and circuit complexity increases
Solution Approach 1:
The patent extracts and eliminates the voltage division resistors (R1 and R2) from the circuit. Instead of using resistive division to generate bias signals, the invention uses the resonant capacitor voltage directly through a different control mechanism, removing the energy-consuming resistive elements while maintaining proper transistor biasing control
Solution Approach 2:
The resonant capacitor Cr serves multiple functions: it provides the resonant function for power conversion and simultaneously serves as the reference for generating bias signals. This multi-functionality eliminates the need for separate voltage division resistors, reducing both power loss and circuit complexity
2Ease of operation
If voltage division and biasing circuits are used to generate higher and lower bias signals, then transistor control is achieved, but circuit complexity increases and transient response capability deteriorates
Solution Approach 1:
The complex voltage division and biasing circuitry is extracted and removed. The patent uses a simplified approach where the resonant capacitor voltage is directly utilized with optional buffering, eliminating multiple resistors and biasing components while maintaining effective transistor control
Solution Approach 2:
Instead of generating bias signals through voltage division and then processing them, the invention inverts the approach by using the resonant capacitor voltage directly as the reference signal for control, optionally through a buffer, thereby simplifying the control signal generation path
3Reliability
If voltage division circuits are used to generate bias signals, then transistor biasing is achieved, but transient response capability becomes poor
Solution Approach 1:
The resistive voltage division circuit is extracted and removed, eliminating the inherent delay and signal degradation associated with resistive networks. The direct use of resonant capacitor voltage provides faster, cleaner signal transitions that improve transient response while maintaining reliable transistor biasing
Solution Approach 2:
The control signals are generated in advance based on the resonant capacitor voltage before the switching events occur, allowing the transistors to be properly biased and ready for switching. This preliminary signal preparation eliminates delays in transient response
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 reduces power consumption, simplifies the circuit, and significantly improves the transient response capability of the resonant power converter.
Implementation Method 1
a resonant circuit, including a resonant inductor, a primary winding of a transformer, and a resonant capacitor, wherein the resonant inductor, the primary winding of the transformer, and the resonant capacitor are serially coupled to each other, and wherein the first transistor and the second transistor are configured to switch the resonant circuit to generate a resonant current for converting an input voltage into an output voltage
Implementation Method 2
The resonant power converter of the present invention achieves this goal by full-wave rectifying the resonant-related signal of the resonant current, and subsequently processing the rectified signal, such as by integration or differentiation, to generate a ramp signal
Data Source
AI summary
A resonant power converter includes: a first and a second transistors, configured to form a half-bridge circuit; a resonant circuit including a resonant inductor, a primary winding of a transformer, and a resonant capacitor, which are serially coupled to each other, and wherein the first and the second transistors are configured to switch the resonant circuit to generate a resonant current for converting an input voltage into an output voltage; and a conversion control circuit configured to generate a ramp signal based on the resonant current, and to generate a first drive signal and a second drive signal based on the ramp signal and a compensation signal related to the output voltage. The first drive signal and the second drive signal are respectively used to control the first transistor and the second transistor. During a signal period of the ramp signal, the ramp signal monotonically increases or monotonically decreases.