EV Converter Control to Suppress Leak-Current Line Voltage
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Solution Overview
Problem
In electrified vehicles, when system main relays (SMRs) disconnect the power storage device from the drive device, leak currents can generate voltage in the electric circuit, leading to erroneous detection or learning during abnormality detection or offset correction processes.
Innovation Solution
The converter is connected to power lines between the SMRs and the drive device, and a control device activates or stops the converter based on voltage applied to these lines, preventing voltage generation due to leak currents by ensuring the converter is stopped when SMRs are disconnected, and activated when they are connected, using a bidirectional DC-DC converter to manage voltage during connection and disconnection processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the converter is disconnected from the power lines between the relays and the drive device, then the risk of voltage generation due to leak current is reduced, but the converter cannot perform abnormality detection or offset learning when the relays are disconnected
Solution Approach 1:
The power lines are segmented into two parts: lines between the relays and converter, and lines between the converter and drive device. The converter is connected to the first segment (power lines from relays) but disconnected from the second segment (power lines to drive device) when relays are open. This segmentation allows the converter to remain powered and functional for detection purposes while preventing leak current from affecting the drive device circuit.
Solution Approach 2:
The converter acts as an intermediary component that can be selectively connected to different parts of the circuit. By maintaining connection to the power lines from the relays while disconnecting from the drive device side, the converter serves as a mediator that enables detection functions without creating harmful voltage paths through the drive device when relays are disconnected.
2Adaptability or versatility
If the converter is connected to the power lines between the relays and the drive device, then the converter can perform abnormality detection and offset learning, but voltage may be generated due to leak current when the relays are disconnected
Solution Approach 1:
The power lines are segmented into two parts: lines between the relays and converter, and lines between the converter and drive device. The converter is connected to the first segment (power lines from relays) but disconnected from the second segment (power lines to drive device) when relays are open. This segmentation allows the converter to remain powered and functional for detection purposes while preventing leak current from affecting the drive device circuit.
Solution Approach 2:
The harmful connection path between the converter and the drive device is extracted or removed when the relays are disconnected. The converter is taken out of the circuit segment that includes the drive device, eliminating the path through which leak current could generate harmful voltage, while maintaining connection to the power supply segment for operational functionality.
3Ease of operation
If a relay is used to connect or disconnect the power storage device and the drive device, then the circuit can be controlled, but leak current in the converter may generate voltage when the relay is disconnected
Solution Approach 1:
The power lines are segmented into two parts: lines between the relays and converter, and lines between the converter and drive device. The converter is connected to the first segment (power lines from relays) but disconnected from the second segment (power lines to drive device) when relays are open. This segmentation allows the converter to remain powered and functional for detection purposes while preventing leak current from affecting the drive device circuit.
Solution Approach 2:
The converter acts as an intermediary component that can be selectively connected to different parts of the circuit. By maintaining connection to the power lines from the relays while disconnecting from the drive device side, the converter serves as a mediator that enables detection functions without creating harmful voltage paths through the drive device when relays are disconnected.
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 configuration effectively suppresses voltage generation in the electric circuit due to leak currents, preventing erroneous detections and malfunctions, and ensuring stable operation by maintaining the converter in a stable state during SMR disconnection and connection processes.
Implementation Method 1
a converter connected to power lines between the relays and the drive device and configured to convert alternating current power supplied from an external power supply into direct current power and charge the power storage device
Implementation Method 2
a converter connected to power lines between the relays and the drive device and configured to convert direct current power in the power storage device into alternating current power and output the alternating current power to an outlet
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
An electrified vehicle (V; Va) includes: a power storage device (10); an electric motor (30) configured to drive a drive wheel (50); a drive device (20) configured to drive the electric motor (30) by using electric power in the power storage device (10); relays (11; 12; 13) configured to connect or disconnect the power storage device (10) and the drive device (20); a converter (110) connected to power lines (PL; NL) between the relays (11; 12; 13) and the drive device (20); and a control device (300) configured to activate the converter (110) or stop the converter (110) when a voltage is applied to the power lines (PL; NL) to which the converter (110) is connected.