Cascode Switched-Mode Full-Wave Rectifier Reduces Voltage Loss
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Solution Overview
Problem
Bridge rectifiers using diodes are inefficient due to voltage losses from forward diode voltages, resulting in significant power conversion inefficiency, particularly in common power supply circuits with input voltages between 85 and 265 volts.
Innovation Solution
A full-wave rectifier design utilizing cascode circuits with switched-mode rectifying paths, comprising controllable switches formed by cascode circuits of normally-on and normally-off transistors, which connect input paths to output paths during specific half waves of the input voltage, minimizing voltage loss and improving efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If diodes are used in bridge rectifier paths, then the rectifier structure is simple and reliable, but voltage loss increases and conversion efficiency decreases
Solution Approach 1:
The patent changes the operating parameters of the rectifier by using transistors operated in linear region instead of diodes, and by controlling the timing of conduction for each transistor. This allows the rectifier to achieve lower voltage drop while maintaining full-wave rectification functionality through coordinated switching of multiple transistor pairs.
Solution Approach 2:
The rectifier is divided into four separate rectifying paths, each with independently controlled transistor pairs. This segmentation allows each path to be optimized for minimal voltage loss while the coordinated operation of all paths maintains the full-wave rectification function, resolving the contradiction between simplicity and efficiency.
2Productivity
If diodes are used in rectifying paths, then the circuit is simple to implement, but power conversion efficiency deteriorates due to forward voltage drops
Solution Approach 1:
The patent employs dynamically controlled transistors that can adjust their conduction timing and duration based on the input voltage waveform. This dynamic control allows the rectifier to minimize voltage losses during conduction while maintaining high power conversion efficiency, overcoming the static limitations of diode-based rectifiers.
Solution Approach 2:
The coordinated control of transistor pairs Q1-Q2 and Q3-Q4 incorporates feedback mechanisms that respond to the input voltage polarity and magnitude. This feedback enables optimal timing control of each transistor pair, maximizing power conversion efficiency while managing the increased circuit complexity through intelligent control strategies.
Data Source
AI summary
A full-wave rectifier is disclosed. In one embodiment the full-wave rectifier includes two input paths configured to receive an alternating input voltage, two output paths configured to provide a direct output voltage, and four switched-mode rectifying paths that are connected between each of the input paths and each of the output paths, wherein the switched mode rectifying paths are configured to connect a first input path to a first output path and a second input path to a second output path during a first half wave of the input voltage, and to connect the first input path to the second output path and the second input path to the first output path during a second half wave of the input voltage, and wherein the switched-mode rectifying paths include cascode circuits.