Dynamic Parallel Capacitor Switching for Low-Loss Semiconductor Turn-Off
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing semiconductor switch technologies face challenges in reducing switching losses across a wide operating range, particularly when high and low currents are involved, and there is a need to improve electromagnetic compatibility (EMC) in circuit designs.
Innovation Solution
A circuit unit comprising a semiconductor switch, an auxiliary switch, a capacitor, and a logic unit is used to determine current intensity and control the auxiliary switch based on predefined threshold values, ensuring optimal switching by connecting or disconnecting the capacitor in parallel with the load path to minimize switching losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If an external capacitance is connected in parallel with a semiconductor switch to reduce switching losses at high currents, then switching losses are reduced and EMC is improved, but device complexity increases
Solution Approach 1:
The patent applies dynamics by making the capacitance connection dynamic rather than static. The auxiliary switch controlled by the logic unit dynamically connects or disconnects the external capacitance based on real-time current intensity detection. This allows the system to adapt to varying operating conditions, reducing switching losses when needed while maintaining simpler operation when the capacitance is not required.
Solution Approach 2:
The system implements self-service through the logic unit that automatically detects current intensity and controls the auxiliary switch to connect or disconnect the capacitance without external intervention. The semiconductor switch circuit serves itself by monitoring its own operating conditions and adjusting the capacitance connection accordingly, eliminating the need for external control mechanisms.
2Loss of energy
If a capacitance is connected in parallel with the semiconductor switch to reduce switching losses, then switching losses are reduced, but the circuit complexity and control requirements increase
Solution Approach 1:
The logic unit provides self-service functionality by automatically detecting the current intensity flowing through the semiconductor switch and autonomously controlling the auxiliary switch to connect or disconnect the external capacitance. This eliminates the need for complex external control circuits or manual intervention, as the system monitors and adjusts itself based on its operating conditions.
Solution Approach 2:
The system implements feedback through the logic unit that continuously monitors the current intensity and uses this information to control the auxiliary switch. The detection of current intensity provides feedback about the operating state, which is then used to adjust the capacitance connection, creating a closed-loop control system that optimizes switching losses automatically.
3Loss of energy
If zero volt switching methods are used to reduce switching losses, then switching losses are reduced, but the adaptability to different current ranges is limited
Solution Approach 1:
The patent applies dynamics by making the capacitance connection conditional based on real-time current detection. The logic unit dynamically determines whether to connect the external capacitance based on the detected current intensity, allowing the system to adapt to different current ranges (high, medium, low currents) rather than being fixed to a single operating mode.
Solution Approach 2:
The system changes the parameter of capacitance connection status based on the detected current intensity. By comparing the detected current against a threshold value and adjusting the capacitance connection accordingly, the system adapts its behavior to different current ranges, optimizing performance across varying operating 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 achieves low switching losses across varying currents and improves EMC by optimizing the switching process, particularly at low currents, while maintaining quasi-zero voltage switching.
Implementation Method 1
a capacitor (which may be a single capacitor or may be composed of a plurality of capacitors connected in parallel)
Implementation Method 2
A series circuit consisting of the auxiliary switch and the capacitor is connected in parallel with a load path of the semiconductor switch
Data Source
AI summary
A circuit unit for reducing switching losses of a semiconductor switch. The circuit unit includes: the semiconductor switch, an auxiliary switch, a capacitor, and a logic unit. A series circuit including the auxiliary switch and the capacitor is connected in parallel with a load path of the semiconductor switch. The logic unit is configured to determine, in a switched-on state of the semiconductor switch, a current intensity of an electric current to be switched using the semiconductor switch and flowing along the load path, close the auxiliary switch or to keep it in a closed state before a switch-off operation of the semiconductor switch when the determined current intensity exceeds a predefined current threshold value, and open the auxiliary switch or to keep it in an open state before a switch-off operation of the semiconductor switch when the determined current intensity does not exceed the predefined current threshold value.