Control Bus Power Supply With Dynamic Current Limiting
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Solution Overview
Problem
Connecting an additional power supply device to a control bus in infrastructure systems can result in current exceeding the maximum limit defined by the applicable standard, potentially damaging connected devices.
Innovation Solution
A power supply device with a short-switching circuit, measurement circuit, and control circuit that dynamically adjusts the output current based on the measured current and standard limits, ensuring the total current on the control bus never exceeds the specified maximum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an additional power supply device is connected to the control bus to maintain system availability, then the system can continue operating during maintenance, but the total current may exceed the maximum limit defined by the control bus standard, potentially damaging connected devices
Solution Approach 1:
The patent applies preliminary action by performing a short-circuit test before the additional power supply device starts providing current. The control circuit temporarily short-circuits the control bus to measure the sum of maximum supply currents of already connected power supply devices, then uses this measurement to calculate and set an appropriate maximum supply current limit for the additional device, preventing current overload before it occurs
Solution Approach 2:
The patent implements feedback by using the measurement circuit to continuously monitor the current state of the control bus and feed this information back to the control circuit. The control circuit adjusts the maximum supply current of the additional power supply device based on the measured current from other devices, ensuring the total current never exceeds the standard limit
2Object-affected harmful factors
If the maximum supply current is fixed at the standard limit, then current overload is prevented, but additional power supply devices cannot be connected after installation
Solution Approach 1:
The patent applies dynamics by making the maximum supply current of the additional power supply device adjustable rather than fixed. The control circuit dynamically determines the maximum supply current based on the measured current from other connected power supply devices, allowing the system to adapt to different numbers of connected devices while preventing current overload
Solution Approach 2:
The patent implements parameter changes by modifying the maximum supply current parameter of the additional power supply device based on the actual system state. The control circuit changes the current parameter from a fixed value to a dynamically adjusted value calculated from the measured current of other devices, enabling both overload prevention and post-installation connectivity
Data Source
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AI summary
A power supply device for a control bus comprises a power supply circuit configured to output an adjustable current to the control bus, and a short-switching circuit configured to selectively apply a short circuit to the control bus. The power supply device further comprises a measurement circuit configured to measure a current on the control bus when the short circuit is applied to the control bus. A control circuit of the power supply device is configured to control the short-switching circuit and the power supply circuit, and the control circuit is configured to determine the adjustable current based on the measured current on the control bus. The invention also includes a method for controlling the power supply device and a driver device including the power supply device for the control bus.