Electric Vehicle Drive Control Device for Regenerative Power Management
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Solution Overview
Problem
Existing propulsion control systems for electric motor cars face issues with detection errors between voltage detectors in inverter and converter apparatuses, leading to inefficient regenerative power collection and fluctuating operation states, resulting in wasted energy and mechanical brake wear.
Innovation Solution
A propulsion control apparatus that generates charging current commands based on regenerative torque suppression amounts, allowing for efficient collection of regenerative power and stabilizing the operation states of converter and power storage apparatuses, even in multiple apparatus configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If voltage detectors are provided in both inverter apparatus and converter apparatus to detect overhead wire voltage, then voltage detection capability is improved, but detection error between the two detectors causes inconsistent control decisions and reduces system reliability
Solution Approach 1:
The patent merges the voltage detection function into a single location (inverter apparatus) and eliminates the duplicate detector in the converter apparatus. The inverter apparatus alone detects the overhead wire voltage and communicates this information to the converter apparatus, ensuring both apparatuses use the same detection data for control decisions, thereby eliminating detection errors while maintaining voltage detection capability.
Solution Approach 2:
The inverter apparatus is given a dual function: it both drives the motor and detects the overhead wire voltage. By making the voltage detection universal to the system through the inverter apparatus, the patent eliminates the need for separate detection in the converter apparatus, ensuring consistent control decisions across both apparatuses.
2Reliability
If regenerative braking force is suppressed to prevent overhead wire voltage rise, then overhead wire voltage stability is improved, but mechanical brake wear increases and regenerative power is wasted
Solution Approach 1:
The patent implements a feedback control mechanism where the inverter apparatus continuously monitors overhead wire voltage and communicates this information to the converter apparatus. The converter apparatus adjusts its regenerative power absorption in real-time based on the detected voltage level, allowing the system to maintain voltage stability while maximizing regenerative power utilization without unnecessary mechanical brake intervention.
Solution Approach 2:
The patent dynamically changes the operating parameters of the converter apparatus based on overhead wire voltage conditions. When voltage is normal, the converter apparatus absorbs maximum regenerative power; when voltage rises above thresholds, it reduces absorption gradually. This parameter adjustment allows the system to maintain voltage stability while minimizing energy waste and reducing mechanical brake wear.
3Productivity
If multiple converter apparatuses with independent voltage detectors are used in a train formation, then system redundancy is improved, but operation state fluctuation increases due to detection errors
Solution Approach 1:
The patent merges the voltage detection function across multiple converter apparatuses by having them all rely on the single detector in the inverter apparatus. Each converter apparatus receives the same voltage detection information from the inverter, ensuring consistent operation states while maintaining system redundancy through multiple power storage apparatuses.
Solution Approach 2:
The patent creates equipotentiality in information distribution by ensuring all converter apparatuses in the train formation receive identical voltage detection data from the inverter apparatus. This equalizes the operational basis for all converter apparatuses, eliminating fluctuations caused by detection errors while preserving system redundancy.
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
This solution enables efficient regenerative power collection and reduces the frequency of mechanical brake operation, thereby minimizing wear and improving energy utilization in electric motor cars.
Implementation Method 1
This power storage system includes a converter apparatus that performs DC-DC conversion and a power storage apparatus including a power storage device such as a secondary battery or an electric double layer capacitor
Data Source
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AI summary
A propulsion control apparatus for an electric motor car includes: an inverter apparatus connected to a DC power supply; a motor connected to an output of the inverter apparatus; a converter apparatus connected to an input of the inverter apparatus; and a power storage apparatus connected to an output of the converter apparatus. The propulsion control apparatus for an electric motor car is configured to discharge a part of power running power or regenerative power of the motor from the power storage apparatus or charge a part of the power running power or the regenerative power in the power storage apparatus. The converter apparatus includes a converter control unit that generates, based on a regeneration state signal as a signal indicating a suppression state of the regenerative power or regenerative torque or regenerative current equivalent to the regenerative power, a charging current command value, which is a command value of an electric current with which the converter apparatus charges the power storage apparatus, generates a charging and discharging current command value of the converter apparatus based on the charging current command value, and performs control.