Resonant Power Converter Current Control for Single-Stage Isolation
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Solution Overview
Problem
Existing power conversion systems require multiple stages for bidirectional power transfer, leading to increased complexity and high magnetic and switch currents, limiting them to low power applications and necessitating additional voltage regulation stages in low noise applications.
Innovation Solution
A single-stage resonant power converter with synchronous average harmonic current control, using a synchronous average harmonic current controller to manage switching and line currents through negative feedback, allowing for efficient bidirectional power transfer and voltage regulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a two-stage power conversion system is used, then galvanic isolation and voltage regulation are achieved, but device complexity and magnetic current increase
Solution Approach 1:
The patent combines the DC-DC conversion and AC inversion functions into a single integrated stage, eliminating the need for separate galvanic isolation and voltage regulation stages. The single-stage resonant power converter performs both power conversion and isolation simultaneously, reducing overall system complexity while maintaining the required galvanic isolation between primary and secondary sides.
2Power
If high magnetic and switch currents are used, then power conversion capability is increased, but the system is limited to low power applications
Solution Approach 1:
The patent employs dynamic resonant switching techniques where the switching frequency is modulated to maintain optimal current levels across varying power conditions. The resonant tank circuit dynamically adjusts its operating point to minimize peak currents while maintaining efficient power transfer, enabling the system to handle higher power levels without requiring excessively high magnetic and switch current ratings.
3Device complexity
If a single-stage converter is used, then device complexity is reduced, but control of switching and line currents becomes difficult
Solution Approach 1:
The patent implements a sophisticated control system with multiple feedback loops that monitor switching currents, line currents, and output voltage in real-time. The controller adjusts switching duty cycles and frequencies based on feedback signals to maintain optimal current waveforms and prevent overcurrent conditions, thereby achieving effective current control despite the simplified single-stage architecture.
4Device complexity
If flyback or auk architecture is used, then parts complexity is minimized, but high magnetic and switch currents are required
Solution Approach 1:
The patent changes the fundamental operating parameters by using resonant switching at optimized frequencies and duty cycles, unlike conventional flyback or auk architectures. By operating in a resonant mode with carefully selected switching parameters, the system achieves lower peak currents for the same power level, thereby extending applicability to higher power applications while maintaining minimal parts complexity.
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 reduces parts complexity and achieves well-controlled switching and load currents in a single stage, enabling efficient bidirectional power transfer and voltage regulation while minimizing synchronous average harmonic currents.
Implementation Method 1
A resonant power converter with synchronous average harmonic current control of switching and line currents
Implementation Method 2
The isolated DC to DC converter stage is usually galvanically isolated to addresses safety and interaction problems
Data Source
AI summary
A synchronous average harmonic current controller is used to simultaneously control line load current and switching transformer current for a resonant power converter. The controller takes its feedback input from a current command and a bridge current sensor which measures total current flowing between the bridge switching nodes. The controller is implemented using an inverting switched capacitor filter. The filter switches two capacitors across the output and inverting node of an error amplifier to integrate and compensate current error synchronously over each half of the fundamental period. The superimposed non-modulated common and modulated difference feedback signals apply duty cycle and phase control which reduces the synchronous average error current. As a result of synchronous average current control of the line load and transformer currents, the primary and secondary bridge have a defined voltage relationship which is straightforward to regulate.