Power Converter Protection Circuit Using Zener-Triggered Switch Clamping
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Solution Overview
Problem
Existing power converter designs for explosion-proof applications rely on high-power Zener diodes for overvoltage protection, which are limited in availability and costly, necessitating the exploration of alternative cost-effective solutions.
Innovation Solution
A protection circuit comprising a series connection of a reverse-polarized Zener diode and a resistor coupled with a semiconductor switch, where the semiconductor switch is controlled by the voltage potential between the Zener diode and resistor, mimicking the behavior of a high-power Zener diode to limit voltage and current, thereby replacing the need for high-power Zener diodes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high-power Zener diodes are used for overvoltage protection, then overvoltage protection is provided, but availability is limited and cost increases
Solution Approach 1:
The high-power Zener diode is segmented into multiple low-power Zener diodes connected in parallel. Each low-power Zener diode handles a portion of the total current, allowing the use of readily available standard components instead of specialized high-power devices. This segmentation maintains the voltage clamping function while improving availability and reducing cost.
Solution Approach 2:
Multiple low-power Zener diodes are merged in parallel configuration to collectively provide the protection function previously requiring a single high-power device. The combined structure achieves the necessary power handling capability through aggregation of multiple standard components, resolving the availability and cost issues.
2Reliability
If multiple Zener diodes in parallel are used for redundancy, then reliability is improved, but device complexity increases
Solution Approach 1:
The protection function is segmented across multiple parallel Zener diodes, where each diode independently contributes to the overall protection. This segmentation provides inherent redundancy without requiring complex control circuits, as the parallel structure naturally ensures continued protection even if one diode fails.
Solution Approach 2:
The parallel-connected Zener diodes provide self-service redundancy where each diode automatically shares the protection load. The system maintains protection capability through the inherent properties of the parallel configuration without requiring external control or monitoring mechanisms, thus avoiding increased device complexity.
3Ease of manufacture
If standard electronic components are used instead of high-power Zener diodes, then cost is reduced, but electrical and thermal characteristics must be maintained
Solution Approach 1:
The electrical parameters of the standard components are carefully selected and adjusted to match the required characteristics. By choosing appropriate voltage ratings, power dissipations, and thermal management parameters for each standard Zener diode, the collective assembly reproduces the electrical and thermal behavior of a single high-power Zener diode, maintaining reliability while reducing cost.
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 solution effectively provides overvoltage protection using standard electronic components, reducing costs and maintaining comparable electrical and thermal characteristics to high-power Zener diodes, while being compatible with existing power converter designs.
Implementation Method 1
Zener diodes are usually reversed polarized so that they limit the voltage on the voltage supply line to a breakthrough voltage above which the current through the Zener diode steeply increases
Implementation Method 2
The semiconductor switch is configured to become conductive when a voltage over the resistor increases over a threshold voltage
Data Source
Figure 1a
Figure 1b
Figure 2a
AI summary
The present invention relates to a protection circuit (3) for a power converter, particularly for explosion-protection applications, comprising: - a series connection of a reverse-polarized Zener diode (DZ1, DZ2) and a resistor R1, R2) to be coupled between a high and a low potential supply line (L1, L2) of the power converter; - a semiconductor switch (TR1, TR2, NMOS, PMOS) particularly directly coupled between the high and low potential supply line (L1, L2) with its conduction path (channel) wherein a control terminal of the semiconductor switch (TR1, TR2, NMOS, PMOS) is coupled with or controlled by a node between the Zener diode and the resistor (R1, R2).