Power Converter Multi-Threshold Switching to Reduce Rectification Loss
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Solution Overview
Problem
Existing power converting apparatuses face efficiency decreases due to increased losses in switching elements when current values become large, as they continue to flow current through switching elements, leading to higher losses and reduced efficiency.
Innovation Solution
A power converting apparatus with a reactor, bridge circuit, current detecting unit, and control unit that uses multiple current thresholds to control the ON/OFF states of switching elements, allowing current to flow through switching elements when losses are low and parasitic diodes when current is high, thereby minimizing overall losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If current flows through switching elements, then low current losses are achieved, but high current losses increase and efficiency decreases
Solution Approach 1:
The patent applies parameter changes by switching between two different operational modes based on current magnitude. When current is small, the system operates in synchronous rectification mode with switching elements ON to minimize conduction losses. When current exceeds a threshold, the system switches to diode rectification mode to avoid quadratic loss increase. This dynamic parameter change optimizes energy loss across different operating conditions.
Solution Approach 2:
The patent implements dynamics by making the rectification mode adaptable rather than fixed. The control unit dynamically determines whether to use synchronous rectification or diode rectification based on real-time current detection. This dynamic switching allows the system to adapt to varying load conditions and maintain optimal efficiency across different current levels.
2Reliability
If switching elements are used for rectification, then synchronous rectification performance is achieved, but efficiency decreases when current value becomes large
Solution Approach 1:
The patent changes the operational parameter of the rectification circuit based on current magnitude. For small currents, synchronous rectification with MOSFETs provides low conduction losses. For large currents exceeding the threshold, the system switches to diode rectification to prevent quadratic loss increase. This parameter-based switching maintains reliable rectification performance while optimizing efficiency across different current levels.
Solution Approach 2:
The patent effectively creates two different rectification pathways: synchronous rectification using switching elements for low-current conditions and diode rectification for high-current conditions. The control unit selects the appropriate pathway based on current detection, allowing the system to copy the behavior of the most efficient rectification method for each operating condition.
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 approach reduces or prevents efficiency decreases by ensuring current flows through elements with lower losses, maintaining high efficiency across varying current values.
Implementation Method 1
a reactor (2) including a first terminal and a second terminal, the first terminal being connected to an alternating-current power supply; a bridge circuit (3) connected to the second terminal of the reactor (2)... converting an alternating-current voltage output from an alternating-current power supply into a direct-current voltage
Implementation Method 2
a current detecting unit (6) detecting a current from the alternating-current power supply
Data Source
AI summary
A power converting apparatus includes: a reactor that includes a first terminal and a second terminal, the first terminal being connected to an alternating-current power supply; a bridge circuit that is connected to the second terminal of the reactor, includes at least one or more switching elements, and converts an alternating-current voltage output from the alternating-current power supply into a direct-current voltage; a power-supply current detecting unit that detects a current from the alternating-current power supply; and a control unit that controls ON and OFF of the switching elements depending on a current value detected by the power-supply current detecting unit, in which two or more current thresholds for controlling ON and OFF of the switching elements are included.