Current Sensing Device Diode Voltage Compensation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current sensing accuracy in eco-friendly vehicles, such as electric and hybrid vehicles, is compromised due to temperature-induced errors in diodes used in current transformers, leading to inaccuracies in current measurement.
Innovation Solution
A current sensing device that includes a temperature sensor, a current sensing unit, and a central processing unit (CPU) to compensate for temperature-related errors in diode forward voltage by storing operation voltages in a map and adjusting the sensing current accordingly, thereby enhancing sensing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a current transformer with diodes is used for current sensing, then current sensing capability is achieved, but temperature-induced errors occur due to diode forward voltage changes
Solution Approach 1:
The system uses a temperature sensor to continuously monitor the temperature of the current transformer and feeds this information back to the CPU. The CPU then adjusts the sensing current based on the temperature feedback, creating a closed-loop system that compensates for diode forward voltage changes and maintains accurate current measurement across varying temperatures.
Solution Approach 2:
The system changes the operating parameters of the current sensing circuit by adjusting the sensing current magnitude based on temperature conditions. The CPU modifies the reference voltage or current levels in response to temperature sensor readings, thereby compensating for the temperature-dependent characteristics of the diodes in the current transformer.
2Measurement precision
If temperature compensation is implemented using a temperature sensor and CPU, then current sensing accuracy is improved, but device complexity increases
Solution Approach 1:
The CPU serves multiple functions: it processes the raw current sensing data, reads temperature sensor data, performs temperature compensation calculations, and outputs corrected current values. By making the CPU multi-functional, the system avoids adding separate dedicated compensation circuitry, thereby limiting the increase in device complexity while still achieving accurate temperature-compensated current measurement.
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 significantly reduces current sensing errors, improves the accuracy of input and output current monitoring, and strengthens overcurrent protection functions, leading to more precise power management and reduced product size and cost.
Implementation Method 1
a current transformer (CT) configured to sense the input current of the power converter
Implementation Method 2
a temperature sensor configured to sense a temperature of a power converter
Data Source
AI summary
A current sensing apparatus includes: a temperature sensor configured to sense a temperature of a power converter; a current sensing unit configured to sense an input current of the power converter; and a central processing unit (CPU) configured to control an operation of the power converter in response to the sensed temperature of the power converter and the sensed input current of the power converter. The CPU includes a compensation unit configured to store, upon receiving an indication of the sensed temperature of the power converter from the temperature sensor, an operation voltage of at least one diode included in the current sensing unit in a map, and to compensate for an error of a sensing current based on the stored operation voltage when the current sensing unit senses the input current.