Bidirectional Electronic Switch PWM Control for Fault Current Limiting
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Solution Overview
Problem
Existing electronic switches in power supply systems lack the ability to efficiently manage current flow and voltage regulation during faults, often requiring abrupt disconnection which can lead to damage or instability, especially in DC networks.
Innovation Solution
An electronic switch with a semiconductor switch and control circuit using pulse-width modulation to intermittently control the switch, allowing for voltage and current regulation, enabling reduced power transmission and gradual disconnection, thus preventing damage and maintaining system stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mechanical switches are used for protection, then isolation is achieved, but switching speed is slow and current zero is required
Solution Approach 1:
The patent replaces mechanical switching mechanisms with semiconductor switches that can be controlled electronically. This substitution eliminates the need for mechanical movement and current zero crossings, enabling much faster switching speeds and allowing operation in DC networks where mechanical switches are unsuitable.
Solution Approach 2:
The patent employs pulse-width modulation (PWM) to control the semiconductor switch, using periodic switching actions at high frequency. This periodic control allows precise regulation of power transmission while maintaining fast switching capability, resolving the contradiction between switching speed and control precision.
2Reliability
If abrupt disconnection is used during faults, then protection is achieved, but system stability deteriorates and damage occurs
Solution Approach 1:
The patent transitions from static switching (abrupt ON/OFF) to dynamic control using PWM modulation. By continuously adjusting the duty cycle of the semiconductor switch, the system can dynamically respond to fault conditions, gradually reducing power transmission to prevent damage while maintaining system stability through controlled transitions.
Solution Approach 2:
The patent implements controlled impedance matching and damping circuits that are activated before complete disconnection occurs. These circuits provide cushioning protection by absorbing energy and preventing voltage spikes during the transition from connected to disconnected state, thereby protecting components while maintaining system stability.
3Ease of operation
If electronic switches with PWM are used, then current regulation is achieved, but device complexity increases
Solution Approach 1:
The patent implements control circuits that automatically adjust PWM parameters based on feedback from current sensors and system state detection. The system self-regulates without requiring complex external control mechanisms, as the control circuit continuously monitors and adapts switching parameters to maintain optimal current regulation while managing its own complexity through integrated feedback loops.
Data Source
AI summary
An electronic switch includes a current sensor and a semiconductor switch having two semiconductors configured to carry and disconnect a current in both directions, and a control circuit configured to operate the semiconductor switch by pulse-width modulation and to determine a phase control factor of the pulse-width modulation as a function of measurement values of the current sensor such that in fault-free operation, the electronic switch remains in the ON state and that two limit values exist for protection. The electronic switch is operated by pulse-width modulation when a first one of the two limit values is exceeded, and the electronic switch is switched off when a second one of the two limit values, which is greater than the first limit value, is exceeded. The electronic switch is configured to reduce an edge steepness of a switching edge as the phase control factor decreases.