Magnetically Coupled DC Current Sensor Dynamic Drive Voltage
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional isolated DC current sensors with static drive voltages face inefficiencies, such as excessive power consumption and inaccurate measurements due to non-ideal core permeability and leakage inductance, which result in trapezoidal secondary current waveforms rather than ideal square waveforms, leading to incorrect current readings.
Innovation Solution
Implementing a dynamic voltage supply that modulates the amplitude and frequency of the drive voltage in response to the secondary current, ensuring measurements are taken during plateau periods, thereby maintaining efficient power usage and accurate current measurement across varying DC currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a static drive voltage is used in the secondary side of the transformer, then the circuit is simple to implement, but the secondary current waveform becomes distorted (trapezoidal instead of square wave) due to non-ideal core permeability and leakage inductance, leading to inaccurate current measurements
Solution Approach 1:
The patent applies the Dynamics principle by transitioning from a static drive voltage to a dynamic drive voltage system. The drive voltage is continuously adjusted based on feedback from the secondary current measurement, allowing the system to adapt to varying DC current levels and maintain accurate measurements across different operating conditions. This dynamic adjustment compensates for the non-ideal core characteristics that cause waveform distortion.
Solution Approach 2:
The patent implements feedback by measuring the secondary current and using this information to adjust the drive voltage. The feedback mechanism allows the system to detect deviations from the ideal square wave waveform and correct them by modifying the drive voltage accordingly, thereby maintaining measurement accuracy despite non-ideal transformer characteristics.
2Measurement precision
If a high static drive voltage is applied to ensure accurate measurements across all DC current levels, then measurement accuracy is maintained, but power consumption increases excessively
Solution Approach 1:
The system dynamically adjusts the drive voltage amplitude based on the measured DC current level. When the DC current is low, a lower drive voltage suffices for accurate measurement, reducing power consumption. When the DC current is high, the drive voltage is increased to maintain measurement accuracy. This dynamic adaptation eliminates the need to maintain high power consumption levels continuously.
Solution Approach 2:
The patent changes the drive voltage parameter dynamically based on operating conditions. By adjusting the amplitude and frequency of the drive voltage according to the measured secondary current, the system optimizes the balance between measurement accuracy and power consumption, avoiding the excessive power consumption associated with maintaining a constantly high static drive voltage.
3Measurement precision
If the drive voltage frequency is kept low to allow the secondary current to reach a plateau for accurate measurement, then measurement accuracy is improved, but the response time to detect changes in DC current decreases
Solution Approach 1:
The system dynamically adjusts the drive voltage frequency based on the measured DC current level and the observed secondary current waveform characteristics. When measurement conditions permit, the frequency is lowered to ensure the secondary current reaches a plateau for accurate measurement. When rapid response is needed or current levels change, the frequency is increased to improve response time while maintaining adequate measurement accuracy through other compensation mechanisms.
Solution Approach 2:
The patent implements parameter changes by dynamically modifying both the amplitude and frequency of the drive voltage. This allows the system to optimize the trade-off between measurement accuracy and response time by adjusting the frequency parameter according to operating conditions, rather than being constrained to a fixed low frequency.
4Device complexity
If the secondary current waveform is allowed to be non-ideal (trapezoidal) to simplify the circuit, then circuit complexity is reduced, but the current measurement becomes incorrect due to the distorted waveform
Solution Approach 1:
The patent uses feedback to detect the distorted trapezoidal waveform characteristics and adjusts the drive voltage accordingly. By measuring the secondary current and comparing it to the expected ideal waveform, the system can identify deviations caused by non-ideal transformer characteristics and compensate for them through dynamic drive voltage adjustment, maintaining measurement accuracy without requiring complex additional circuitry.
Solution Approach 2:
The system changes the drive voltage parameters (amplitude and frequency) to compensate for the waveform distortion. By adjusting these parameters dynamically, the system can maintain accurate current measurements even when the secondary current waveform deviates from the ideal square wave shape, thereby avoiding the need for complex correction circuits.
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 dynamic drive voltage system enables precise measurement of DC currents by optimizing plateau periods, reducing power consumption, and maintaining accurate readings regardless of DC current levels, thus overcoming the limitations of static drive voltage systems.
Implementation Method 1
The DC current flowing through the primary side generates a field that ultimately induces a current in the secondary side
Data Source
AI summary
A method for measuring current includes passing a DC current through the primary side of a transformer and driving the secondary side of the transformer with an AC voltage, wherein the current in the secondary side of the transformer reaches a plateau. The current in the secondary side of the transformer is measured during the plateau, wherein the measured current is proportional to the DC current.