EV Power Supply Relay Control for Reduced Loss
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Solution Overview
Problem
The existing power supply systems for electric vehicles with multiple power storage devices connected in parallel experience increased power loss due to the number of relays used, which reduces energy efficiency.
Innovation Solution
A power supply system with a power control unit, first and second power storage devices, and switches that selectively form different power feed paths based on input/output current, using a third switch for charging, to minimize relay power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple relays are used to connect power storage devices in parallel, then the power supply capacity is increased, but the power loss increases and energy efficiency decreases
Solution Approach 1:
The patent implements dynamic relay control where the controller selectively turns relays ON or OFF based on real-time power supply demands and system state. Instead of keeping all relays permanently ON to maintain parallel connection capability, the system dynamically activates only the necessary relays, thereby reducing power loss while maintaining the ability to scale power capacity when needed.
Solution Approach 2:
The system changes the operational parameters of relays by controlling their ON/OFF states based on varying power requirements. The controller adjusts which relays are active depending on the current power demand, transforming the static relay configuration into a dynamic parameter-controlled system that optimizes between power capacity and energy efficiency.
2Adaptability or versatility
If multiple relays are turned ON to connect power storage devices, then the power feed flexibility is improved, but the fixed power feeding paths increase power loss
Solution Approach 1:
The patent creates dynamic power feeding paths by controlling relays to be selectively ON or OFF based on system needs. The controller can reconfigure which power storage devices are connected to the load in real-time, maintaining path flexibility while avoiding the energy waste associated with permanently active relays and fixed connection paths.
3Reliability
If relays with large current capacity are used, then the reliability is improved, but the power consumption of relays increases
Solution Approach 1:
The system dynamically selects which relays to activate based on the actual current load requirements. High current-capacity relays are only turned ON when large current flow is actually needed, rather than remaining permanently active. This dynamic activation strategy maintains system reliability when high power is required while minimizing relay power consumption during normal operation.
Data Source
Figure 1
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Figure 5
AI summary
First and second system main relays (SMR1, SMR2) are connected between a first power storage device (11) and a second power storage device (12), respectively, and a first power line (PL1, PL2). First and second relays (CHR1, CHR2) for charging are connected between first and second power storage devices (11, 12), respectively, and a second power line (PL2, NL2). A control device (100) selectively forms any of a first power feed path (PA) formed by connecting each of the first and second power storage devices (11, 12) to the first power line (PL1, NL1), and a second power feed path (PB1, PB2) formed by connecting, to the first power line (PL1, NL1), one of the first and second power storage devices (11, 12) connected in parallel when the first and second relays (CHR1, CHR2) are turned ON, thereby ensuring a power feed path to the load.