Propulsion Controller Filter Capacitor Voltage for EMI Suppression
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Solution Overview
Problem
In propulsion controllers for railway vehicles, the switching between asynchronous and synchronous modes based on filter capacitor voltage and main motor speed can lead to unintended increases in electromagnetic noise, especially during constant speed brake operations.
Innovation Solution
A propulsion controller with a filter capacitor, inverter, power consumption circuit, and controller that performs mode switching control and power consumption control. The controller adjusts the target value of the filter capacitor voltage to shift the operating point from synchronous to asynchronous mode, reducing electromagnetic noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If synchronous mode is used for constant speed brake operation, then the operation can be maintained at constant frequency, but electromagnetic noise increases
Solution Approach 1:
The invention changes the filter capacitor voltage parameter dynamically during constant speed brake operation. By adjusting the voltage command value to increase the filter capacitor voltage above the switching threshold, the system forces mode switching from synchronous to asynchronous mode, thereby eliminating electromagnetic noise while maintaining constant frequency operation through the asynchronous PWM control
2Adaptability or versatility
If mode switching is performed based on filter capacitor voltage and main motor speed, then the propulsion controller can adapt to different operating conditions, but unintended increases in electromagnetic noise occur
Solution Approach 1:
The invention introduces feedback control by continuously monitoring the filter capacitor voltage and comparing it with a switching threshold. The controller adjusts the voltage command value based on this feedback to maintain the filter capacitor voltage above the threshold during constant speed brake operation, ensuring the system remains in asynchronous mode and preventing unintended electromagnetic noise generation
Solution Approach 2:
The invention makes the filter capacitor voltage dynamic rather than fixed. By continuously adjusting the voltage command value during operation, the system can adaptively maintain the operating point in the asynchronous mode region, preventing unintended mode switching and electromagnetic noise while preserving the adaptability to different operating conditions
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 solution effectively suppresses unintended increases in electromagnetic noise by controlling the operating point to favor the asynchronous mode, thereby reducing noise levels during operations like constant speed brake operations.
Implementation Method 1
a filter capacitor (7) that smooths a voltage of power supplied from an overhead contact line (1) via a line breaker (31, 32)
Implementation Method 2
an inverter (8) that applies an alternating-current voltage at a variable voltage and a variable frequency to a main motor (9) by pulse width modulation control
Implementation Method 3
a power consumption resistor (52) connected in series with the switching element (51), and is connected in parallel with the inverter (8)
Data Source
AI summary
A propulsion controller includes a controller that performs mode switching control and power consumption control, on the basis of a filter capacitor voltage and a main motor speed. The mode switching control switches between an asynchronous mode and a synchronous mode. The power consumption control causes power consumption resistor of a brake chopper circuit to consume regenerative power generated when a main motor operates as a generator. The controller controls an operating point, depending on the position of which the asynchronous mode and the synchronous mode are switched, to a desired position by changing a target value of the filter capacitor voltage controlled by the power consumption control.