Temperature Compensating Element for Accurate Current Sensing
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Solution Overview
Problem
Current current sensing mechanisms in power electronic circuits, such as DC/AC inverters and DC/DC converters, face significant accuracy variations over a wide temperature range (-40° C to 150° C, leading to reduced reliability and increased power loss due to temperature-dependent sense current fluctuations.
Innovation Solution
Incorporating a temperature compensating element with a positive or negative temperature coefficient, such as a resistor, in close proximity to the current sensor, which adjusts resistance based on temperature changes to maintain consistent current sensing accuracy, thereby reducing temperature-induced fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current sensor is used in power electronic circuits, then current sensing capability is provided, but sensing accuracy varies significantly over temperature range
Solution Approach 1:
The patent changes the electrical parameters (resistance, capacitance, or inductance) of the compensating element to counteract temperature-induced variations in the sense current. By selecting an element with appropriate temperature coefficient, the circuit parameters are adjusted dynamically with temperature to maintain constant sensing accuracy across the operating range.
Solution Approach 2:
The compensating element acts as an intermediary component that mediates between the temperature variations and the current sensor. This element is specifically chosen and positioned to counterbalance the temperature effects on the sense current, thereby protecting the measurement accuracy from temperature fluctuations.
2Measurement precision
If temperature compensating element is added, then sensing accuracy over temperature is improved, but device complexity increases
Solution Approach 1:
The compensating element is selected from existing passive components (resistors, capacitors, inductors) that are already part of standard electronic circuits. This allows the temperature compensation function to be integrated into existing circuit designs without adding fundamentally new components, thereby limiting the increase in device complexity.
Solution Approach 2:
The compensating element is positioned in close proximity to the current sensor, specifically at locations where temperature effects are most pronounced. This localized placement ensures that the compensation is applied exactly where needed, rather than requiring system-wide modifications, thus minimizing overall circuit complexity.
3Reliability
If temperature compensating element is added, then sensing accuracy is improved, but additional components and complexity are introduced
Solution Approach 1:
The patent achieves reliability improvement by changing the parameters of existing circuit elements (such as selecting a resistor with specific temperature coefficient) rather than adding complex active compensation circuits. This approach enhances sensing reliability through parameter optimization with minimal additional components.
Solution Approach 2:
The compensating element uses simple, inexpensive passive components that can be easily replaced if needed. These basic elements provide reliable temperature compensation without the complexity and cost of sophisticated active compensation circuits, maintaining high reliability with minimal component count.
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 enables accurate and efficient current sensing with minimal additional complexity, allowing for fast response times and reduced power loss, particularly beneficial for short circuit detection and overload protection in applications like motor drives and air-conditioning compressors.
Implementation Method 1
In order to compensate for temperature dependent variations of the sense current, it is proposed to embed an additional element with appropriate temperature coefficient into the transistor
Data Source
AI summary
An example relates to a circuit comprising an electronic switching element and an temperature compensating element, which is arranged in the vicinity of the electronic switching element.