Ideal Diode Bridge Rectifier Circuit with MOSFET Control
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Solution Overview
Problem
Conventional switched-mode power supply devices using a full-wave rectifier bridge suffer from significant forward voltage drops in diodes, leading to wasted power and reduced efficiency, especially in high voltage applications where ideal diode bridge rectifiers with MOSFETs are limited by the gate-to-source voltage rating.
Innovation Solution
A rectifying circuit employing an ideal diode bridge with MOSFETs, controlled by a processor-driven system that measures current and phase to determine conducting settings for the diodes, allowing for efficient conversion of AC to DC voltage while avoiding the limitations of conventional silicon diodes and MOSFET voltage ratings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional silicon diodes are used in the rectifier bridge, then the circuit structure is simple, but the forward voltage drop is high (1.5V or more) causing wasted power and reduced efficiency
Solution Approach 1:
The patent replaces silicon diodes with MOSFETs, changing the fundamental parameter of the switching element. MOSFETs have much lower on-resistance compared to diode forward voltage drop, reducing conduction losses significantly. The controlled switching of MOSFETs enables ideal diode behavior with minimal voltage drop during conduction.
Solution Approach 2:
The patent substitutes the passive diode component with an actively controlled MOSFET system. Instead of relying on the inherent diode forward voltage characteristics, the system uses electronic control to achieve ideal switching behavior, replacing a passive component with an active controlled system.
2Loss of energy
If ideal diode bridge rectifiers using MOSFETs are used, then power efficiency is improved, but the input voltage cannot exceed the gate-to-source voltage rating of the MOSFETs
Solution Approach 1:
The patent divides the high voltage input into multiple lower voltage stages by using a series string of MOSFETs. Each MOSFET experiences only a fraction of the total input voltage, specifically the gate-to-source voltage, while the series combination handles the full high voltage input. This segmentation allows the use of low-voltage-rated MOSFETs in high-voltage applications.
Solution Approach 2:
The patent transitions from a single MOSFET handling the full voltage to multiple MOSFETs arranged in series, adding a dimensional aspect (series configuration) to the circuit topology. This series arrangement distributes the voltage stress across multiple components, enabling high voltage operation while maintaining individual MOSFET voltage ratings.
3Loss of energy
If MOSFETs are used as ideal diode elements, then forward voltage drop is minimized improving efficiency, but complex control circuitry is required to manage on-off transitions
Solution Approach 1:
The patent employs feedback control where the controller monitors the AC input voltage and load conditions, then adjusts the MOSFET switching timing and duration accordingly. This feedback mechanism ensures optimal conduction angles and prevents excessive voltage drops while protecting the MOSFETs from overvoltage conditions, automatically adapting to varying operating conditions.
Solution Approach 2:
The controller pre-establishes the conducting settings for MOSFETs based on detected AC voltage characteristics before the rectification process begins. By determining the appropriate on-off transitions in advance based on voltage phase and magnitude, the system prepares the MOSFETs to switch at optimal moments, minimizing voltage drops and preventing harmful conditions.
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 enhances power supply efficiency by minimizing voltage drops and enabling higher input voltages, as the MOSFETs are controlled to optimize conduction settings, thereby reducing energy loss and improving overall performance.
Implementation Method 1
four ideal diode elements connected in a bridge configuration... each one of the ideal diode elements and configured to drive the corresponding one of the ideal diode elements... converting an alternating current (AC) input voltage from a source to a direct current (DC) output voltage
Data Source
AI summary
There is described a rectifying circuit and method of control thereof. The circuit comprises four ideal diode elements connected in a bridge configuration; four driver units, each one of the driver units connected to a corresponding one of the ideal diode elements and configured to drive the corresponding one of the ideal diode elements; and a controller connected to the driver units and configured for: acquiring a current measurement flowing across the load and a phase measurement of the source; determining, from the current measurement and the phase measurement, corresponding conducting settings for the four ideal diode elements; and outputting at least one control signal to cause the driver units to drive the ideal diode elements in accordance with the conducting settings.