Chopper Circuit Control Device for Voltage Stability
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Solution Overview
Problem
In electric trains, when a fault occurs in the voltage converter, the control of semiconductor elements halts, leading to power supply disruptions to load devices, and existing solutions fail to maintain output voltage within a defined range, affecting air-conditioning and lighting equipment.
Innovation Solution
A chopper circuit control device with a range calculator and controller that calculates an operation value range based on input voltage and output voltage command values, using upper and lower limit values to control the duty cycle and maintain output voltage within a defined range, even when faults occur.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If control of semiconductor element halts after fault detection in voltage converter, then overvoltage or undervoltage is prevented, but power supply to load device halts
Solution Approach 1:
The patent changes the control parameter from binary (control halt or no halt) to a continuous adjustment of duty cycle within a calculated safe range. The range calculator determines upper and lower limit duty cycles based on input voltage and output voltage command value, allowing the controller to adjust the duty cycle dynamically while preventing overvoltage/undervoltage conditions, thus maintaining both voltage stability and power supply continuity
Solution Approach 2:
The patent introduces dynamic adjustment of the duty cycle within a calculated safe range rather than static control halt. The range calculator continuously computes safe duty cycle limits based on real-time input voltage and output voltage command value, enabling the controller to dynamically adapt the duty cycle to maintain output voltage within specified range while keeping power supply active
2Reliability
If duty cycle is adjusted to compensate for output voltage deviation, then output voltage stability is improved, but duty cycle may exceed safe range causing overvoltage or undervoltage
Solution Approach 1:
The patent implements feedback control where the controller calculates duty cycle based on deviation between actual output voltage and output voltage command value, then uses range calculator to determine safe upper and lower limit duty cycles. The controller adjusts duty cycle within these calculated limits, creating a feedback mechanism that maintains output voltage stability while preventing overvoltage/undervoltage conditions through bounded adjustment
Solution Approach 2:
The range calculator performs preliminary calculation of safe duty cycle upper and lower limits before the controller adjusts the duty cycle. This preliminary action establishes safety boundaries that prevent overvoltage or undervoltage conditions while allowing the controller to make necessary adjustments within these pre-calculated safe ranges
Data Source
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AI summary
A range calculator (12) calculates an operation value range, which is range of an operation value for controlling a duty cycle of a chopper circuit (4) based on an input voltage and output voltage command value of the chopper circuit (4). A chopper circuit control device (1) controls the duty cycle of the chopper circuit (4) by using an upper limit value of the operation value range when an operation value is greater than or equal to the upper limit value of the operation value range, by using the operation value when the operation value is within the operation value range, and by using a lower limit value of the operation value range when the operation value is less than or equal to the lower limit value of the operation value range.