Primary Side Regulation for Resonant Power Converters
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Solution Overview
Problem
Current power converters, especially those using resonant circuit technologies for medium and high-power applications, face challenges in implementing effective primary side regulation to maintain a constant current output, as existing methods are complex or inadequate for these power ranges.
Innovation Solution
The implementation of a current sense circuit with a transformer coil ratio, sensing resistors, and a voltage reference regulator allows for primary side regulation of a resonant switch mode power converter, using equations to define output current and input current relationships, enabling the controller to adjust the operating frequency and maintain a constant output current over multiple cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If secondary side regulation is used to regulate output current, then constant current can be maintained, but device complexity increases due to opto-couplers and electrical isolation components
Solution Approach 1:
The patent extracts the current sensing function from the secondary side and implements it on the primary side by sensing the input current directly. This eliminates the need for opto-couplers and electrical isolation components while maintaining constant current regulation capability.
Solution Approach 2:
The primary side controller performs multiple functions: it senses the input current, regulates the output current based on the sensed input current, and controls the switching operation. This multi-functionality eliminates the need for separate secondary side sensing components.
2Device complexity
If primary side regulation is used in low-power implementations, then device complexity is reduced, but regulation effectiveness becomes inadequate for medium and high-power implementations
Solution Approach 1:
The patent changes the regulation parameter from secondary current to primary input current. By sensing and regulating based on input current characteristics, the system achieves effective regulation across low, medium, and high-power ranges without requiring different regulation approaches for different power levels.
3Loss of energy
If resonant circuit technologies are used for medium and high-power applications, then power conversion efficiency is improved, but suitable primary side regulation technique becomes unavailable
Solution Approach 1:
The patent implements a feedback mechanism where the input current is sensed and used to regulate the output current. The controller adjusts switching parameters based on the sensed input current to maintain proper output current levels, providing the needed regulation technique for resonant circuit technologies in medium and high-power applications.
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 effectively regulates output current at a constant value across varying power ranges, enhancing the efficiency and precision of power conversion in medium and high-power applications, including those using resonant circuit technologies.
Implementation Method 1
by adjusting the duty cycle (the ratio of the time that the primary coil is 'on' versus the total time the primary coil is both 'on' and 'off' time), the voltages induced in the primary coil and thereby in the output voltage of the transformer may be varied
Data Source
AI summary
Various embodiments of devices, systems, and methods for regulating the output current of a switched mode, resonant power converter using primary side regulation. For at least one embodiment, a circuit for primary side regulation of a constant output current resonant transformer includes a transformer having a first coil with a first terminal and a second terminal. A controller circuit is configured to receive an input voltage and a resonant circuit is coupled to the controller circuit and the first terminal. A current sense circuit is coupled to the second terminal and to the controller circuit. The current sense circuit is configured to detect fluctuations in a sensed resulting voltage potential representative of the output current of the transformer. The current sense circuit is configured to provide a feedback signal to the controller circuit when the sensed resulting voltage potential is greater than a reference voltage.