Current Controller for High-Voltage Step-Charge
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Solution Overview
Problem
Network-powered equipment faces limitations in high voltage step charging due to current restrictions, which can lead to excessive losses and undesirable time constraints, and existing solutions are inadequate for managing surge currents and fault conditions, especially in adverse environments.
Innovation Solution
A current controller apparatus with a sensing circuit and a controllable series element that monitors and limits supply current, enabling programmable hiccup mode operation to prevent fault conditions and ensure safe charging of bulk capacitance, using a semiconductor device like a Field Effect Transistor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If constant current charging method is used for large bulk capacitance, then charging current is controlled, but excessive losses occur in the input power switch and charging time becomes unacceptably long
Solution Approach 1:
The patent implements periodic pulsed charging where the power switch operates in discrete on/off cycles. The controller applies current in controlled pulses rather than continuous flow, allowing the bulk capacitance to charge in stages. This periodic operation reduces average power dissipation in the switch while maintaining acceptable charging time by optimizing pulse width and frequency.
Solution Approach 2:
The patent dynamically adjusts the charging current profile by modifying the duty cycle and frequency of pulsed operation. The controller varies the on-time and off-time of the power switch to optimize charging efficiency at different stages of capacitance charging, adapting the current delivery to match the instantaneous charging requirements and minimize losses.
2Productivity
If peak current is increased to charge large bulk capacitance faster, then charging time is reduced, but the power switch operates outside its Safe Operating Area and may be destroyed
Solution Approach 1:
By using periodic pulsed charging with controlled duty cycle, the patent enables faster charging than continuous low-current methods without requiring excessive peak currents. The pulsed operation allows the switch to handle higher instantaneous currents safely by limiting the duration of each pulse, keeping the average stress within Safe Operating Area limits while achieving acceptable charging speed.
Solution Approach 2:
The controller implements preliminary current limiting and staged charging sequences before full power operation. By gradually increasing the charging current in controlled steps and pre-conditioning the bulk capacitance, the system prepares the power switch for higher current operation, preventing immediate overload conditions that would push the device outside its Safe Operating Area.
3Reliability
If hiccup current limiting is implemented to protect against fault conditions, then power switch is protected, but the solution becomes more complex
Solution Approach 1:
The patent integrates multiple functions into the existing pulsed charging control logic. The same controller that manages the periodic charging pulses also implements fault detection, current limiting, and hiccup protection modes. By making the control circuit universal—capable of handling both normal charging operation and fault conditions with a single integrated logic structure—the patent avoids adding separate dedicated protection circuits, thereby limiting the increase in overall system complexity.
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
Effectively manages peak current demand and fault conditions, preventing network power supply overload, allowing efficient charging of bulk capacitance while maintaining the Safe Operating Area of the power switch, and enabling self-monitoring and adaptive operation.
Implementation Method 1
a controllable series element through which supply current flows and which can be rendered non-conductive by the current controller
Data Source
AI summary
An over-current input conditioning limiter is disclosed for remote equipment. The over-current input conditioning limiter includes a current sensing apparatus, a semiconductor switch, and a programmable controller for controlling the peak current drawn from a pair of supply lines. The over-current input conditioning limiter is particularly useful for overcoming voltage collapse and over-current shutdowns of network power supplies feeding remote apparatus known in the art.