Power Conversion Device Protective Controller Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing power conversion devices in electric railway vehicles face challenges in performing protective operations under diverse conditions, as they may not adequately control output power within desired ranges, leading to excessive power input to load devices due to external disturbances or malfunctions.
Innovation Solution
A power conversion device with a protective controller that calculates and compares multiple values corresponding to output and input power to determine when to stop power conversion, ensuring the power remains within target ranges, thereby enabling protective operations under various conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate protective operations are performed for overcurrent, overvoltage, and other events, then the output current can be controlled to match the command value, but the output power may fall outside the desired range due to external disturbances
Solution Approach 1:
The patent implements feedback control by continuously monitoring output power and comparing it with the command value. When the output power deviates from the command value by exceeding a predetermined threshold, the system generates a protective stop signal to halt power conversion. This closed-loop feedback mechanism ensures that both current control precision and power range reliability are maintained.
Solution Approach 2:
The patent introduces an intermediary protective operation unit that acts as a mediator between the power conversion unit and the load. This unit calculates output power, compares it with the command value, and determines whether to generate a protective stop signal. The intermediary unit coordinates the protective operations, ensuring comprehensive power range control while maintaining current control precision.
2Measurement precision
If feedback control is performed based on output current, then the output current approaches the command value, but excessive power input to load devices can occur due to external disturbances
Solution Approach 1:
The system uses dual feedback control: one loop controls output current to match the command value, while another loop monitors output power and compares it with the command value. When power deviation exceeds a threshold, a protective stop signal is generated. This layered feedback approach prevents excessive power input to loads while maintaining current control accuracy.
Solution Approach 2:
The patent applies preliminary anti-action by proactively monitoring output power and comparing it with the command value before excessive power reaches the load. When the output power is determined to be outside the desired range, the system preemptively generates a protective stop signal to prevent harmful excessive power input, rather than reacting after the problem occurs.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
A power conversion device 1 includes a power conversion unit 11 to convert an input power into an output power, a regular controller 15 to perform control of the power conversion unit 11, and a protective controller 16 to perform protective operation of the power conversion unit 11. The regular controller 15, on the basis of current command value in accordance with a target value of an output of the power conversion unit 11 and an output current of the power conversion unit 11, for example, outputs a control signal to control on-off switching of switching elements included in the power conversion unit 11. When at least one value corresponding to the output power of the power conversion unit 11 is not within the target power range determined in accordance with the target value of the output, the protective controller 16 stops the power conversion by the power conversion unit 11.